Contents. Liberator Phase 1 Field Development Environmental Statement

Transcription

1 September 2017

2 Contents Details... 7 Non-Technical Summary Introduction The Liberator Phase 1 Field Development Project Background and Purpose i3 Energy s Environmental Awareness Scope of the EIA Legislation and Policy The Project Description Consideration of Alternatives Process Well selection strategy Selection of processing facilities Selection of pipeline specifications and routes Drilling Description Nature of reservoir Drilling strategy Vertical seismic profiling (VSP) Drill rig Well design Mud system and cuttings Cementing and other chemicals Well testing and clean up Well suspension Well workovers and interventions Subsea Pipeline and Umbilical New pipeline Umbilical requirements

3 Gas lift Seabed preparation Pipeline and umbilical lay Tie-in installation Pipeline and umbilical protection and crossings Pipeline and spool pre-commissioning Umbilical pre-commissioning Operations and maintenance Host Modifications Production Production profiles Produced water Power generation, venting and flaring Vessel Requirements Decommissioning Environmental Description Introduction Physical Environment Weather and sea conditions Bathymetry and seabed conditions Biological Environment Benthos Fish and shellfish Seabirds Marine mammals Conservation Offshore conservation Coastal conservation Species Socio-Economic Environment Oil and gas activity Offshore wind farms Commercial fisheries

4 Telecommunication cables Military activity Shipping Archaeology and other infrastructure EIA Methodology EIA Overview Environmental Issues Identification (ENVID) Stakeholder Engagement Environmental Significance Overview Baseline characterisation and receptor identification Impact definition Receptor definition Consequence and significance of potential impact Residual impacts Cumulative and In-Combination Impact Assessment Transboundary Impact Assessment Habitats Regulation Appraisal (HRA) Data Gaps and Uncertainties Baseline data Project data Potential for Impact Impact Assessment Introduction Discharges to Sea Description and quantification of impact Mitigation Cumulative and in-combination impact assessment Transboundary impact assessment Decommissioning Protected sites Residual impact Seabed Disturbance

5 Description and quantification of impact Mitigation Cumulative and in-combination impact assessment Transboundary impact assessment Decommissioning Protected sites Residual impact Underwater Noise Description and quantification of impact Mitigation Cumulative and in-combination impact assessment Transboundary impact assessment Protected sites Residual impact Residual impact Other Sea Users Description and quantification of impact Mitigation Cumulative and in-combination impact assessment Transboundary impact assessment Decommissioning Residual Impact Atmospheric Emissions Description and quantification of impact Mitigation Cumulative and in-combination impact assessment Transboundary impact assessment Decommissioning Protected sites Residual impact Accidental Events Description and quantification of impact Mitigation

6 Cumulative and in-combination impact assessment Transboundary impact assessment Socio-economic vulnerability to spills Decommissioning Protected sites Residual impact Environmental Management Conclusions Introduction Scottish National Marine Plan Protected Sites Cumulative/In-combination and Transboundary Impacts Environmental Impacts Final Remarks References Appendix A ENVID Matrix Appendix B Supporting Data for Accidental Events Assessment Appendix C Environmental Commitments

7 Details Section A: Administrative Information A1 Project Reference Number Please confirm the unique ES identification number for the project. Number: D/4199/2017 A2 - Applicant Contact Details Company name: i3 Energy Contact name: Stuart Mcilroy Contact title: HSEQ Manager A3 - ES Contact Details (if different from above) Company name: Contact name: Contact title: A4 - ES Preparation Please confirm the key expert staff involved in the preparation of the ES: Name Company Title Relevant Qualifications/Experience Stuart McIlroy i3 Energy HSEQ Chartered Member of The Institution of Manager Occupational Safety and Health Kenneth Couston A5 - Licence Details Xodus Group EIA Delivery Lead 36 years experience in HSE in oil and gas MSc in health, safety and risk with environmental management IEMA Practitioner a) Please confirm licence(s) covering proposed activity or activities Licence number(s): P1987 b) Please confirm licensees and current equity 9 years experience as environmental consultant Undergraduate and postgraduate degree in environmental discipline Licensee i3 Energy 100% Percentage Equity 7

8 Section B: Project Information B1 - Nature of Project a) Please specify the name of the project. Name: Liberator Phase 1 Field Development b) Please specify the name of the ES (if different from the project name). Name: c) Please provide a brief description of the project. The Liberator Phase 1 Field Development comprises a simple arrangement of two wells located in UKCS Blocks 13/23d and 13/24a, approximately 64 km from the south Moray coast in the South Halibut Basin of the Moray Firth. i3 Energy is proposing to develop the Liberator field via two single wells, one close to an existing manifold (part of the Repsol Sinopec-operated Blake field) and one approximately 2 km from the same manifold. Produced fluids from the two Liberator wells will co-mingle with fluids from wells drilled into the Blake field from the Blake manifold. These co-mingled fluids are processed by the Repsol Sinopec operated Bleo Holm Floating Production, Storage and Offloading vessel. B2 - Project Location a) Please indicate the offshore location(s) of the main project elements (for pipeline projects please provide information for both the start and end locations). Quadrant number(s): 13 Block number(s): 23d, 24a Latitude: Longitude (W / E): N, W (Blake manifold) Distance to nearest UK coastline (km): 64 Which coast? England / Wales / Scotland / NI Distance to nearest international median line (km): 171 Which line? UK / Norway B3 - Previous Applications If the project, or an element of the project, was the subject of a previous consent application supported by an ES, please provide details of the original project Name of project: Date of submission of ES: Identification number of ES: 8

9 EIA Quality Mark This (ES), and the Environmental Impact Assessment (EIA) carried out to identify the significant environmental effects of the proposed development, was undertaken in line with the EIA Quality Mark Commitments. The EIA Quality Mark is a voluntary scheme, operated by the Institute of Environmental Management and Assessment (IEMA), through which EIA activity is independently reviewed, on an annual basis, to ensure it delivers excellence in the following areas: EIA Management; EIA Team Capabilities; EIA Regulatory Compliance; EIA Context & Influence; EIA Content; EIA Presentation; and Improving EIA Practice. To find out more about the EIA Quality Mark please visit 9

10 Non-Technical Summary Introduction This (ES) presents the findings of the Environmental Impact Assessment (EIA) conducted by i3 Energy for the development of the Liberator field through two wells that will tie-back to the existing Blake manifold and be processed through the existing Bleo Holm Floating Production Storage and Offloading unit (FPSO). This proposal is termed The Liberator Phase 1 Field Development. The expected life of field is seven years and there will be no requirement to extend the stay of the Bleo Holm FPSO beyond that already approved. The Liberator wells will be located in UKCS Blocks 13/23d and 13/24a, approximately 64 km from the south Moray coast in the South Halibut Basin of the Moray Firth (Figure 1). Drilling is expected to commence in April 2018 with first oil expected in the second half of 2018, although tie-in of the second well and production start-up from this well may not occur until August Figure 1 Location of the Liberator field 10

11 Environmental Management The management of environmental risks associated with i3 Energy s activities is integral with the business decision making process. Environmental hazards are identified at all stages for the Liberator Phase 1 Field Development and are assessed and managed via ongoing monitoring and Integrated Management System (IMS). Managing Environmental issues associated with the Liberator Phase 1 Field Development Project are important to i3 Energy; as a new operator in the North Sea, the company is keen to demonstrate awareness of the environmental requirements and to have an environmental management system that supports the development and commitments associated with the submission of a formal Environmental Statement. 11

12 Consideration of Alternatives The development option selected for the Liberator Phase 1 Field Development was arrived at following a documented option evaluation and selection process. The selection process took cognisance of environmental, health and safety, technical, Project execution and commercial issues and risks and included a comprehensive value assurance review. Well engineering studies demonstrated that two drill centres were optimal for the Project, balancing drilling cost and risk against subsea infrastructure costs. The subsurface work programme demonstrated that two wells, one at each drill centre, provided the optimum reserves recovery solution. Early in the screening process for processing facilities, two host options were identified as viable for the Liberator Phase 1 Field Development: Option 1: Wells to be tied in to the Blake manifold with fluids returned to the Bleo Holm FPSO for processing; and Option 2: Wells to be tied in to a new subsea manifold with fluids returned to a new FPSO for processing. Following review of the options against i3 Energy technical and commercial screening criteria, it was determined that the preferred option was Option 1. This option was thus approved by the Board of Directors of i3 Energy and is presented as the selected option in this ES. Options for the location of the second well were evaluated with the technical risk of drilling the western extremity of the reservoir from the Blake manifold being compared to the additional cost and impact of drilling from a technically more secure location 2 km to the west. After careful evaluation, the western location was calculated to present the most efficient and highest chance of drilling success. Drilling Operations The Liberator reservoir will be developed with deviated wells using the Ocean Guardian or similar drilling rig. The selected rig will be a semisubmersible, with an eight chain anchor pattern for maintaining position whilst drilling. The Liberator reservoir will be developed by the drilling of two wells, L1 and L2. L1 will be drilled close to the existing Blake manifold and tied back to it via a short pipeline and umbilical (consisting of rigid spool pieces and jumpers 1 ), both of which will be trenched. L2 will be drilled approximately 2 km west of the Blake manifold and tied back to the existing Blake manifold via a 2 km rigid or flexible pipeline and separate control umbilical. Drilling is expected to commence in Both wells will be of a similar design and each well will be drilled to approximately 3,782 m. The well will be drilled in four sections of successively smaller diameters. The well will be directionally drilled, meaning it will deviate progressively further from vertical, with last 1 A spool or spool piece is a short prefabricated and shaped rigid pipeline section used to connect or tie in a pipeline to a manifold or other infrastructure. A jumper is a similar structure but is used to transport chemicals and to transfer electronic controls. 12

13 section orientated horizontally to allow a horizontal completion in the oil-producing zone. Different types of mud are planned to be used for different parts of the wells. The top two sections will be drilled without a marine riser in place, and seawater and bentonite will be pumped in to remove cuttings and keep the hole clean. Cuttings and bentonite from these top hole sections will be discharged to sea from the top of the hole at the seabed. The next section will be drilled with either a water based mud (WBM) or a low toxicity oil based mud (LTOBM). If WBM is used, the cleaned cuttings will be discharged overboard. If LTOBM is used, the cleaned cuttings will be stored in skips and shipped to shore for treatment and disposal. The deepest section will be drilled with WBM, with cleaned cuttings discharged overboard. Steel casings will be installed in the wells to provide structural strength to support the subsea trees, isolate unstable formations and different formation fluids and separate different wellbore pressure regimes. Each steel casing will be cemented into place, which will provide a structural bond and an effective seal between the casing and surrounding rock formation. Prior to production, each well will be cleaned up to remove any waste and debris remaining in the well to prevent damage to the pipeline or topsides production facilities. A well test may then be conducted at the drill rig to obtain reservoir information and fluid samples. During well clean up and testing, up to 2,000 tonnes of oil may be produced per well. Oil produced during well testing will be flared. Any gas produced during well testing will also be flared; flared gas is not expected to exceed approximately 200 tonnes per well. Subsea Operations Installation of structures at Well L1 will commence in July 2018 and installation of the trenched production pipeline and the control umbilical to Well L2 is expected to be completed between Q1 and Q Subsea trees (structures to control the flow of oil and gas made up of pipework and valves within a supporting steel framework) will be installed on top of the wellheads during drilling operations. The subsea tree provides a mechanism for flow control and well entry. Both wells will have a sub-surface safety valve installed which is an isolation device that is hydraulically operated and fail-safe closed. During the drilling phase, the subsea trees will be controlled from the drill rig, whilst during production the subsea trees will be remotely controlled from the Bleo Holm FPSO via control umbilicals. The trees on both wells will incorporate a Scottish Fishermen s Federation (SFF) approved fishing-friendly tree protection structure similar to those installed over other infrastructure in the area, able to resist loads from potential fishing interactions whilst minimising risk to fishing vessels. Well L1 will be tied into the Blake manifold using a 6" diameter 100 m spool and an approximately 4.5" diameter 100 m control jumper, both of which will be surface-laid. A 6" production pipeline of approximately 2 km length will run between the L2 well and the L1 well, where it will be tied in to the L1 production spool. An approximately 4.5" diameter control umbilical of approximately 2 km length that will provide electrical supply, hydraulic fluids and chemicals will also run between the L2 well and the L1 well, where it will be tied in to the control jumper running between L1 and the Blake manifold. The other ends of the 13

14 pipeline and umbilical at the L2 well will be tied into the well using a suitable spool and jumper. Approximately 100 concrete mattresses, each measuring 3 m by 6 m by 0.5 m will be required to secure and protect the spools and jumpers. It is estimated up to five sections of rock, each measuring 20 m long by 2 m wide may be needed to prevent the pipeline from buckling. A recent geophysical and geotechnical survey has been carried out along the proposed pipeline and umbilical route, to enable finalisation of route design taking into account any seabed features or obstructions that could impede installation. A pre-lay ROV survey will be carried out prior to installation to re-check the route to determine whether any new obstructions have appeared. During installation, boulders may need to be moved outside of the pipeline and umbilical corridors. Figure 2 shows a schematic of the Liberator Phase 1 Field Development. Figure 2 Liberator Phase 1 Field Development layout schematic i3 Energy is considering injecting gas at high pressure into the base of the wells to mix with the produced hydrocarbons. This inflow of gas has the effect of reducing the density of the fluids, assisting with their delivery to the top of well. If the decision is made to use gas lift, a gas lift spool of approximately 100 m length will be installed on the seabed between the Blake manifold and Well L1. A steel pipeline of 2" or 4" diameter will run between Well L1 and Well L2, being installed in the same trench as the umbilical. Production Operations At present the assumption is that there will be no requirement to modify the Blake manifold, the pipeline and umbilical between Blake and the Bleo Holm FPSO, and any of the topsides processing system at the Bleo Holm FPSO. As such, no impact assessment has been conducted 14

15 on the transport of fluids between the Blake manifold and the Bleo Holm FPSO, or onwards transport of those fluids from the Bleo Holm FPSO. However, the processing of produced fluids from the Liberator field may result in changes in fuel use and produced water discharge from the Bleo Holm FPSO. Production will come online in 2018, with approximately 9,560 barrels (1,091 tonnes 2 ) of oil and 70,400 standard metres cubed (Sm 3 ) of gas produced per day. Production will peak in 2020 at approximately 15,600 barrels of oil (1,990 tonnes) and 105,300 Sm 3 of gas per day, before steadily declining over the remainder of the projected field life of seven years. Environment Baseline Information about the environment at the Liberator field and its surroundings was collated to allow an assessment of those features that might be affected by the proposed drilling, installation, operation and decommissioning activities. The key sensitivities of the areas are summarised below in Table 1. Table 1 Environmental sensitivities in the area of the Liberator field Seabed associated species Fish and Environmental sensitivity Survey work carried out around the Liberator field found that water depth within the area surveyed varied between 100 m in the east and 135 m in the southwest. Occasional depressions 10 m to 130 m across and up to 3 m deep have been found across the survey area. The seabed was poorly sorted fine sand to very poorly sorted coarse silt with some areas of gravel. In terms of the European Nature Information System (EUNIS) broad-scale habitat classification, the seabed type at both well locations is deep circalittoral sand. Analysis of samples taken revealed a fairly rich, generally evenly distributed community. Polychaete worms were the most abundant taxa at all stations, in particular Prionospio dubia, Paramphinome jeffreysii and Galathowenia oculata which occurred ubiquitously and accounted for 29% of all adults identified. Dominance of polychaetes worms is typical from North Sea sediments where they are expected to represent at least 50% of macrofaunal species in a sample; therefore the total contribution in these samples was slightly higher than expected for the fine sandy sediment present. Observed epifauna included low densities of seapens. Although faunal burrows were present, megafauna was sparse and consisted mainly of polychaetes, starfish, brittlestars, urchins, jellyfish, corals, anemones hermit crabs, fish and molluscs. The Liberator field is located in an area that is utilised as a spawning and nursery ground by cod, herring, lemon sole, Norway lobster, Norway pout, sandeel, sprat and whiting, as a spawning ground for plaice, and as a nursery ground for anglerfish, blue whiting, European hake, haddock, ling, mackerel, spotted ray and spurdog. Many species, whether pelagic or demersal by nature, including sprat, whiting, cod, lemon sole, Norway pout, and plaice spawn into the water column over large areas and so their eggs and juveniles are unlikely to be significantly impacted by the proposed operations in the Liberator field. Herring are indicated as spawning in the Liberator field in the months of August and September. The characteristic that distinguishes this species from others is that it requires a specific benthic habitat on which to lay its eggs, and such habitat is very limited and only occurs in relatively small areas.. A herring spawning ground assessment indicated there was no potential for herring spawning in the Liberator field. 2 Oil conversions calculated using a conversion factor of barrels per tonne. 15

16 Seabirds Marine mammals Conservation Other sea users Environmental sensitivity In the Liberator field, the sensitivity of seabirds to surface oiling varies from low to high throughout the year, being lowest in July and August and highest in February. Seabirds are most vulnerable to oil spills during moulting, when they become flightless and spend a lot of time on the sea surface. As the Liberator field is located a significant distance from shore, seabirds are unlikely to congregate here in high densities at any time of the year, even during moulting. Six cetacean species are likely to occur within the vicinity of the Liberator field: harbour porpoise, bottlenose dolphin, white-beaked dolphin, Atlantic white-sided dolphin, killer whale and minke whale. The harbour porpoise and the white-beaked dolphin are the most frequently recorded cetaceans in the vicinity of the Liberator field with sightings in eight months of the year which is reflective of those being the most abundant and widely distributed cetaceans in the North Sea. There is one proposed site of conservation interest located at a distance of 36 km from the Liberator field, which is the Southern Trench. It has been proposed for MPA designation for the presence of minke whales in high relative density compared to wider Scottish territorial waters, as well as for its frontal zones that create hotspots of pelagic biodiversity, its shelf deeps representing potential nursery areas for certain fish species, and finally for its burrowed muds which is home to the Norway lobster and giant seapens. There is no other site of conservation interest within 40 km of the Liberator field. A total of 61 juveniles of the ocean quahog (a long-lived species of clam) was found across fifteen of the twenty samples and nine of the ten stations. This species is on the OSPAR (2008) list of threatened and/or declining species in the North Sea and is also listed as a Feature of Conservation Importance and Priority Marine Feature. The Development area appears to support burrowing infauna and low densities of sea pens, which may be consistent with the Priority Marine Feature Burrowed mud. However the area is not included in any of the current areas of search for this feature, and as such it is unlikely to represent an outstanding example of the feature. Surveys indicate that the Liberator field does not support any Annex I habitat. The area is not known to support any other features of conservation importance. The Liberator field is located in International Council for Exploration for the Seas statistical rectangle 45E8. Although fished by UK and international vessels, this rectangle is rated as low in terms of fishing value and effort. There are several active oil and gas fields in the vicinity. The closest active infrastructure to the Liberator field are related to the Blake, Ross and Captain fields. Shipping density is low in the area surrounding the Liberator field. Environmental Impact Methodology Offshore activities can involve a number of environmental interactions and impacts due, for example, to operational emissions and discharges and general disturbance. The objective of the EIA process is to incorporate environmental considerations into the Project planning, to ensure that best environmental practice is followed and, ultimately, to achieve a high standard of environmental performance and protection. The process also allows for any potential concerns identified by stakeholders to be addressed appropriately. In addition, it ensures that the planned activities are compliant with legislative requirements and i3 Energy s Environment policy. The main processes used to identify which potential impacts this EIA should concentrate on were environmental issues identification (ENVID), based on the accumulated experience of 16

17 relevant engineers and environmental specialists, and agreed through consultation with the main offshore regulator the Offshore Petroleum Regulator for Environment and Decommissioning (OPRED) and its advisors: Marine Scotland, the Joint Nature Conservation Committee (JNCC) and the Scottish Fishermen s Federation (SFF). Together, these approaches led to the following key issues being identified for assessment: Discharges to sea, such as cuttings and chemicals; Seabed disturbance, such as through rig anchoring, use of mattresses, rock placement, pipeline and umbilical installation and drilling discharges; Underwater noise, and potential effects on marine mammals; Interactions with other sea users; Atmospheric emissions; and, Accidental events. To help inform these assessments, the following supporting studies were also conducted: Site-specific seabed survey to assess the possible presence of habitats and species of conservation importance; and Accidental hydrocarbon release modelling, to facilitate assessment of the impacts from worst case scenarios regarding accidental spills of either light oil or diesel fuel. Discharges to Sea Discharges to sea during the drilling phase of the Project include drilling mud, cuttings, cement and clean-up and well test chemicals. Discharges from the subsea infrastructure include chemicals in treated seawater, used initially within the pipeline system (including spools, manifolds and umbilicals) for cleaning and integrity testing through the installation and commissioning phases. There will be no new discharge streams to sea during production, with associated incremental produced water discharge resulting in increased chemical and hydrocarbon discharge to sea. These discharges may lead to potential impacts to the seabed or water column through the following mechanisms: Increased suspended solids in the water column; Settlement of cuttings and muds on the seabed; and Potential toxic impacts from the chemical additives within the discharges. The biota in the Liberator field is not expected to be particularly sensitive to chemical toxicity or physical disturbance from the anticipated discharges, and are expected to recover quickly from disturbance. Chemicals used will be selected for their low toxicity, and produced water will be treated to ensure the oil in water content is less than 30 mg/l. Chemical discharges will be subject to further assessment and modelling under the Offshore Chemical Regulations 2002 (as amended). Potential impacts are expected to be intermittent and short-term. Discharges associated with the Liberator Phase 1 Field Development will not occur within or affect any protected site. 17

18 Considering the characteristics of the potential discharges, the low sensitivity of the receptor species and the potential for recovery, the consequence of the potential impact due to discharge of cuttings to the seabed and to the water column is therefore considered to be low and not significant for all phases of the project. Seabed Disturbance The drilling of two wells is likely to be conducted using a semi-submersible drill rig. This will be moored using eight anchors. The maximum anchor spread radius at each well location will be 2,500 m, of which approximately 1,000 m is estimated to lie on the seabed. A small area of seabed where each anchor is placed will be compressed as the anchors sink into the seabed. Consequently, the placement of the anchors and mooring lines will cause localised direct damage to the habitats and species at the point of placement, whilst the movement of the associated lines as they sweep back and forth across the seabed whilst the rig is in position will abrade the seabed and associated benthic communities. Physical disturbance is also likely to be caused during installation of the wellheads, pipeline, umbilical, gas lift line, spools and jumpers as well as by mattresses and/or rock laid for protection purposes which can cause mortality or displacement of benthic species in the direct footprint. The significance of direct habitat loss or mortality of sessile seabed organisms depends on the footprint of the area of disturbance, the level of tolerance of the affected habitat and species to direct disturbance, the conservation value of the affected habitat or species and the uniqueness of the affected habitats or species assemblages to the area. In addition to the direct loss and/or disturbance of benthic habitats within the Liberator Phase 1 Field Development footprint, seabed disturbance around the footprint periphery will also potentially lead to indirect impacts through the smothering of benthic species and habitats due to sediment suspension and re-settlement. Rock placed on the seabed, installation of subsea facilities, and installation and retrieval of anchors associated with the drill rig is likely to result in some sediment suspension and re-settlement. Exposure to higher than normal loads of suspended sediment has the potential to negatively affect adjacent habitats and species. The re-settlement of sediments can result in the smothering of epifaunal benthic species. Most of the area affected by seabed disturbance will only be impacted temporarily, with recolonisation from the surrounding area and from the water column driving a swift recovery. There will be a very small area that will experience a long-term change in the distribution of species present, but this area is negligible when compared to the available similar habitat in the surrounding area. There were no protected habitats identified in the Project area during seabed surveys, and the sediment type within the Project area is widespread in the surrounding area, suggesting that the sensitivity of the benthos in the area is low and the potential for recovery following disturbance is high. It is possible that there will be existing drill cuttings accumulations from previous wells located around the Blake manifold. Disturbance of these cuttings accumulations during Liberator Phase 1 Field Development could cause further small impacts on the seabed via smothering as described above. Any existing drill cuttings will be identified prior to commencement of 18

19 operations, and installation work will be routed to avoid disturbance and resuspension of this material. Considering all of the above, noting that there will be no impact on protected sites or on species from protected sites and that the footprint of the Project for the life of field (anticipated at seven years) will be localised, the residual consequence of seabed disturbance is ranked as low and therefore not significant. Underwater Noise Many species found in the marine environment use sound to understand their surroundings, track prey and communicate with members of their own species. Some species, mostly toothed whales, dolphins and porpoise, also use sound to build up an image of their environment and to detect prey and predators through echolocation. The potential impacts of industrial noise on species may include impacts to hearing and displacement of the animals themselves and potential indirect impacts which may include displacement of prey species or stress. Noise sources that have been identified as likely to occur during the Liberator Phase 1 Field Development and which, depending on the specific nature of the sources, could cause injury or disturbance to marine mammals and fish are limited to vessel (from engines and propellers) and vertical seismic profiling (VSP), should it become apparent during drilling that reservoir conditions are significantly different to what is currently expected. Noise emissions from vessels are not expected to cause injury. However, they may be sufficiently loud for marine mammals and fish to find the noise a nuisance and to remove themselves from the area for the duration of activities. Such exclusion might be considered significant if it occurred for extended periods of time in areas that were important for breeding or feeding (which does not apply to the Liberator field). Mitigation measures to reduce the potential for injury and disturbance to marine mammals from VSP will include pre-shoot searches by a qualified marine mammal observer, delay of operations to allow sighted animals to leave the area, and soft-starts (gradually increasing the power) of the air gun at the beginning of operations and following suspension of operations for more than 10 minutes. The rig will make use of anchors to hold position, eliminating the need to maintain station using noisy dynamic positioning thrusters. Noise emissions from vessels are not expected to be sufficient to cause physical injury to marine mammals. Whilst there is the potential for noise from VSP operations to cause injury, it is expected that the proposed mitigation measures will ensure there are no marine mammals within the potential injury zone, and the possibility of injury to marine mammals will therefore be eliminated. The only potential impact that could therefore potentially occur is through changes to behaviour, within a few hundred metres of the VSP source. However, it is unlikely that many, if any, marine mammals would be present within the zone during operations, not least because VSP would not commence if there were any marine mammals identified within the zone. There is a possibility that vessel noise and VSP could disturb and / or injure small numbers of fish within a few hundred metres of the sound source. However, given the large and 19

20 widespread populations of the fish species expected to be encountered in the Liberator field, it is not expected that vessel noise or VSP would result in population level impacts on fish. Although most vessel use will occur during the drilling and installation periods, there is likely to be a limited requirement for vessel use during maintenance activities. The residual impact will therefore occur intermittently over the seven year life of the Liberator Phase 1 Field Development, and is unlikely to be distinguishable from the existing level of impact arising from operations at Blake. Considering all of the above, the residual impact of the noise emitted by the Liberator Phase 1 Field Development is categorised as low and is therefore not significant. Interactions with Other Sea Users Use of the sea by both the oil and gas and the fishing industries brings with it the potential for interactions. Impacts arising from this interaction can include direct and indirect exclusion of fishing and shipping from certain areas, damage to fishing gear from seabed debris and obstacles, and damage to oil and gas industry subsea facilities by fishing gear. Although there will be an increase in the number of vessels in the area during installation and commissioning phases of the Liberator Phase 1 Field Development, these activities will only be of a relatively limited duration. Fishing and other shipping activity in the Development area is of low intensity, reducing the potential for interaction. Standard communication and notification procedures will be in place to ensure that all vessels operating in the area are aware of the activities, including the presence of the drilling rig and associated vessels. Whilst the drill rig is on location in the Liberator field, a temporary safety exclusion zone of 500 m radius will be maintained. The purpose of this safety exclusion zone is to ensure the safety of all personnel involved in the drilling activities and to minimise the risk of collisions between the vessels involved with the drilling activities and other vessels in the area. Following the drill rig going off site, an exclusion zone of 500 m radius around the L2 drill centre will be maintained throughout the seven years of anticipated field life. The L1 well will be located within an existing 500 m safety zone. The pipelay, rock placement and associated support vessels will exclude other sea users around their immediate vicinity, but only for the very short period of time (60 days maximum) these vessels are working on location. The residual risk on other sea users by the Liberator Phase 1 Field Development will be low and is therefore not significant. Atmospheric Emissions The emission of gases to the atmosphere from the Liberator Phase 1 Field Development could potentially result in impacts at a local, regional, transboundary and global scale. Local, regional and transboundary issues include the potential generation of acid rain from nitrogen and sulphur oxides (NOx and SOx) released from combustion, and the human health impacts of ground level nitrogen dioxide (NO2), sulphur dioxide (SO2), both of which will be released from combustion) and ozone (O3), generated via the action of sunlight on NOx and volatile 20

21 organic compounds (VOCs). On a global scale, concern with regard to atmospheric emissions is increasingly focused on global climate change. Atmospheric emissions from the Liberator Phase 1 Field Development during drilling, installation and commissioning will be related largely to fuel consumption by the drill rig, installation vessels and helicopters and flaring activities during the well clean-up and possible well testing. Emissions during the operational phase will mostly be those resulting from any increased fuel use at the Bleo Holm FPSO in order to process the additional production from Liberator. Any releases from drilling, installation and commissioning vessels will be transitory, whilst emissions from operational activities will be intermittent throughout the seven years anticipated for field life. The Liberator field is too remote from other industrial activities (including other offshore oil and gas activity) for there to be any likely cumulative effects in terms of local air quality. Whilst there will be some increase in fuel use at the existing Bleo Holm FPSO, the additional potential emissions are sufficiently low that no cumulative impact on local air quality is expected. The drilling activities associated with the Liberator Phase 1 Field Development will be at closest approximately 171 km from the UK/Norway median line; therefore, there will be no significant transboundary impacts. Overall, the assessment shows that the potential emissions from the Liberator Phase 1 Field Development will likely have a limited cumulative effect in the context of the release of greenhouse gases (GHGs) into the environment and their contribution to global climate change (i.e. will no cumulative or transboundary impact). Considering all of the above, including that there will be no impact on protected sites or on species from protected sites, the residual risk of atmospheric emissions from the Liberator Phase 1 Field Development will be low and is therefore not significant. Accidental Events The risk of an accidental hydrocarbon spillage to the sea is often one of the main environmental concerns associated with oil-industry activities. Spilled hydrocarbons at sea can have a number of environmental and economic impacts, the most conspicuous of which are on seabirds and coastal areas. The actual impacts depend on many factors, including the volume and type of hydrocarbon spilled, the sea and weather conditions at the time of the spill, and the oil spill response. At Liberator the expected hydrocarbon is likely to be gas and light oil; therefore the expected hydrocarbon for this Project has been assumed (on a worst-case basis) to be light oil, and the following single event has been identified as having the potential to cause a hydrocarbon spill: Uncontrolled well blow-out at Liberator L1 (30,341 m 3 oil over 84 days at a variable flowrate representing the maximum flow from the well over the blowout period). Well blowout modelling based on this scenario indicated that: The shortest arrival time for oil to beach in the UK was 2 days in the spring season; 21

22 There was a high probability (90-100%) of oil crossing the UK/Norway transboundary line within three days in the winter season; The probability of shoreline oiling was generally less than 30% for most areas; and The areas at most risk are expected to be in Scotland, specifically Grampian (up to 70% probability within 2 days) and Orkney (up to 40% probability within 2.5 days). The consequences of a significant release of hydrocarbons from the Liberator Phase 1 Field Development, which is located approximately 64 km from shore, will vary depending on factors such as wind speed and direction and sea state, as well as the time of year and the length of coastline affected. Whilst the potential consequences of a well blowout are severe, the likelihood of a well blowout occurring during operations in the Liberator field is remote. The most likely spill risk is associated with hose failure during transfer of drilling mud, diesel and chemicals during drilling operations. These spills are expected to be small in volume and procedures will be in place to reduce the risk and consequence of any spill, in particular written procedures, regular inspection of equipment and provision of spill kits. Even with comprehensive prevention measures in place (including a device called a blowout preventer, which can seal, control and monitor a well), the residual risk of a spill remains, and integral to offshore operations is the formulation of detailed and fully tested contingency response plans. i3 Energy has in place a range of response/mitigation measures to address such risks. All drilling activities will be covered by approved Oil Pollution Emergency Plans. The Oil Pollution Emergency Plan sets out the responses required and the available resources for dealing with all spills. The planning, design and support of all activities for the Liberator Phase 1 Field Development will aim to eliminate or minimise potential environmental risks. As described, these impacts are being mitigated through the equipment design, spill risk reduction measures and provision of appropriate spill response arrangements. i3 Energy s Integrated Management System (IMS) processes are in place to ensure that these mitigation commitments are implemented and monitored. Considering the controls described above and the mitigation measures that will be put in place, the residual risk will be very low and is therefore considered to be not significant. Decommissioning i3 Energy will review decommissioning best practice closer to the point at which the Project will be decommissioned. Full consideration will be given to available decommissioning options, including reuse and removal. Mitigation and Controls As described above, a number of mitigation measures that have been developed to ensure that the potential impact from the Liberator Phase 1 Field Development is not significant. Development of mitigation measures has considered whether or not seasonal sensitivities are 22

23 sufficiently great to drive scheduling commitments. The commitments identified as part of this environmental impact assessment will be incorporated into an Environmental Management Plan for the Project and will evolve and be updated at each stage of the Project, continuing through the execution and operational phases. Conclusions The Liberator Phase 1 Field Development EIA has considered the objectives and marine planning policies of the Scottish National Marine Plan across the range of policy topics including natural heritage, air quality, cumulative impacts and oil and gas. i3 Energy considers that the Liberator Phase 1 Field Development is in broad alignment with such objectives and policies. The i3 Energy IMS will ensure that measures described in this to minimise and mitigate against environmental impact will be delivered by the project through the establishment of an environmental management plan for the installation, commissioning production operations and decommissioning of the Liberator Phase 1 Field Development. Overall, it is concluded that the limited geographical scale of Phase 1 of the Development (limited to two wells) and the limited temporal scale of Phase 1 of the Development (life of field is anticipated to be seven years), combined with the proposed mitigation measures, mean that the Liberator Phase 1 Field Development will not result in any significant long-term environmental impacts. 23

24 Acronyms for the Non-Technical Summary EIA ENVID ES EUNIS FOCI FPSO GHGs IMS JNCC km LTOBM NOx NO 2 O 3 OPRED OSPAR ROV SFF Sm 3 SO 2 SOx UK VOCs VSP WBM Environmental Impact Assessment Environmental Issues Identification European Nature Information System Feature of Conservation Importance Floating Production Storage and Offloading Greenhouse Gases Integrated Management System Joint Nature Conservation Committee kilometres Low Toxicity Oil Based Mud Nitrous Oxides Nitrogen Dioxide Ozone Offshore Petroleum Regulator for Environment and Decommissioning Oslo Paris Convention Remotely Operated Vehicle Scottish Fishermen s Federation Standard cubic metres Sulphur Dioxide Sulphur Oxides United Kingdom Volatile Organic Compounds Vertical Seismic Profiling Water Based Mud 24

25 1 Introduction 1.1 The Liberator Phase 1 Field Development The Liberator field is located in United Kingdom Continental Shelf (UKCS) Block 13/23d, approximately 64 km from the south Moray coast in the South Halibut Basin of the Moray Firth (Figure 1-1). The Liberator field was discovered in 2013 and is not currently exploited for the production of oil and gas. Figure 1-1 Location of the Liberator field 1.2 Project Background and Purpose Oil and gas production and development company i3 Energy acquired 100% of the operating licence and working interest from Dana Petroleum and now intends to develop the first phase 25

26 of the Liberator field, called the Liberator Phase 1 Field Development, through two wells in UKCS Blocks 13/23d and 13/24a that will tie-back to the existing Blake manifold (Figure 1-2) and be processed through the existing Bleo Holm Floating Production Storage and Offloading unit (FPSO) (Figure 1-3). The anticipated seven year life of field for the Liberator Phase 1 Field Development will not require the Bleo Holm FPSO to remain on station longer than is currently approved. i3 Energy is considering the possibility of developing the Liberator field through a further phase of the overall field development. Such a development would be subject to further field development planning and environmental assessment process and is not discussed further herein. 26

27 Figure 1-2 Proposed Liberator wells in context of existing in relation to existing Blake manifold and Bleo Holm FPSO Figure 1-3 The existing Bleo Holm FPSO, on which produced fluids will be processed (Bluewater, 2017) The Liberator Phase 1 Field Development has a number of potential economic benefits for the UK: Generation of additional revenue to the UK Government from increased oil and gas production; Contribution to the security of the UK s energy supply; On a local and national scale, the Project may secure or add to the onshore and offshore employment in the area, in particular during the drilling and installation phases; and Extended use of the existing production infrastructure which may facilitate future developments in the area. Front End Engineering Design (FEED) for the Project is scheduled to be completed in early 2018, following which Detailed Design will continue through early Offshore activities are scheduled to begin with drilling of well L1 in May 2018 and both wells will be drilled and completed by the end of August First oil is expected to be produced from well L1 in Q3 of Well L2 will be drilled and suspended whilst the pipeline and umbilical to the Blake manifold are laid and commissioned, which should be completed in Q2 2019, at which point well L2 will be brought online. The preliminary schedule for the Liberator Phase 1 Field Development is summarised as follows: Drilling of well L1 May to July 2018; 27

28 Tie-in of well L1 July to August 2018; Drilling of well L2 July to August 2018; Suspension of well L2 end of August 2018; Pipelay and tie-in of well L2 up to one year following the end of drilling; and First oil Q i3 Energy s Environmental Awareness The management of environmental risks associated with i3 Energy s activities is integral with the business decision making process. Environmental hazards are identified at all stages for the Liberator Phase 1 Field Development and are assessed and managed via ongoing monitoring and IMS. Managing environmental issues associated with the Liberator Phase 1 Field Development Project are important to i3 Energy; as a new operator in the North Sea, the company is keen to demonstrate awareness of the environmental requirements and to have an environmental management system that supports the development and commitments associated with the submission of a formal. The commitments of i3 Energy regarding environmental management are described in Figure 1-4 below. Further details on how environmental commitments made in this ES will be taken forward into execution of the Liberator Phase 1 Field Development are given in Section Scope of the EIA The overall aim of the EIA is to assess the potential environmental impacts that may arise from the Liberator Phase 1 Field Development and to identify the measures that will be put in place to reduce these potential impacts. The EIA process is integral to the Project, assessing potential impacts and alternatives, and identifying design and operational elements to help reduce the potential impacts of the Project as far as reasonably practical. The process also provides for stakeholder involvement so that issues can be identified and addressed as appropriate at an early stage, and helps to ensure planned activities comply with environmental legislative requirements and with i3 Energy s environmental policy. The EIA scope covers installation, commissioning and operational activities, and decommissioning of the Project over which i3 Energy has operational control. Specifically, the EIA has considered routine and accidental events associated with: Drilling, well testing of and production from the two Liberator wells and associated structures; Installation, operation and maintenance of the new pipeline, umbilical and spools; Incremental impacts at the Bleo Holm FPSO as a result of production from the Liberator field; and Decommissioning of the Liberator field (including the wells, gas pipeline and umbilical). At present the assumption is that there will be no requirement to modify the Blake manifold, the pipeline and umbilical between Blake and the Bleo Holm FPSO, and any of the topsides 28

29 processing system at the Bleo Holm FPSO. As such, no impact assessment has been conducted on the transport of fluids between the Blake manifold and the Bleo Holm FPSO, or onwards transport of those fluids from the Bleo Holm FPSO. However, the processing of produced fluids from the Liberator field may result in changes in fuel use and produced water discharge from the Bleo Holm FPSO and these aspects have been considered in the EIA. This ES reports the EIA process and the results of the assessment. The scope of the EIA was developed during consultation and an Environmental Issues Identification (ENVID) workshop (refer to Chapter 4). Full details of the method applied during the EIA process are described in Chapter 4. Figure 1-4 i3 Energy environmental policy 29

30 1.5 Legislation and Policy The EIA reported in this ES has been carried out in accordance with the requirements of the Offshore Petroleum Production and Pipelines (Assessment of Environmental Effects) Regulations 1999, as amended (including by the Offshore Production and Pipe-lines (Environmental Impact Assessment) (Amendment) Regulations 2017). These Regulations require the undertaking of an EIA and the production of an ES for certain types of offshore oil and gas developments likely to have a significant impact on the environment. An EIA is mandatory for any offshore oil and gas development that is expected to produce more than 500 tonnes of oil per day or more than 500,000 m 3 gas per day. An EIA is also required for pipelines greater than 40 km in length or with an overall diameter of more than 800 mm. The Liberator Phase 1 Field Development triggers an EIA on the grounds of oil production. There are a number of other key regulatory drivers applicable to the Project, with the key legislation being: The Petroleum Act 1998; The Petroleum Licensing (Production) (Seaward Areas) Regulations 2008; Energy Act 2008, as amended; The Offshore Petroleum Activities (Conservation of Habitats) Regulations 2001, as amended; The Offshore Marine Conservation (Natural Habitats &c.) Regulations 2007, as amended; The Offshore Petroleum Activities (Oil Pollution Prevention and Control) Regulations 2005, as amended; The Offshore Chemical Regulations 2002, as amended; The Merchant Shipping (Prevention of Pollution by Garbage) Regulations 1998; The Merchant Shipping (Oil Pollution Preparedness, Response & Co-operation Convention) Regulations 1998; The Merchant Shipping (Prevention of Air Pollution from Ships) Regulations 2008 (as amended); Oil Pollution Preparedness, Response and Co-operation Convention Regulations 1998 as amended; The Offshore Installations (Emergency Pollution Control) Regulations 2002; The Marine and Coastal Access Act 2009; The Marine (Scotland) Act 2010; The Marine Strategy Regulations 2010 (which implement the European Marine Strategy Framework Directive); and 30

31 Offshore Installations (Offshore Safety Directive) (Safety Case etc.) Regulations The EIA Regulations require that the EIA should consider the likely significant impacts of a project on the environment. The scope of the EIA is informed by a number of different processes, including an environmental issues identification (ENVID) workshop and consultation with stakeholders. Following this, the decision-making process related to defining whether or not a project has the potential to cause significant impact on the environment, this is the core principle of the EIA process. The EIA Regulations themselves do not provide a specific definition of significance, but they indicate that the methods used for identifying and assessing potential impacts should be transparent and verifiable. A defined methodology has been adopted by i3 Energy to make the assessment as objective as possible. In addition, European Union Directive 92/43/EEC on the conservation of natural habitats and of wild flora and fauna, more commonly known as the Habitats Directive, provides protection to European sites (Special Areas of Conservation, SACs), and the Birds Directive (Special Protection Areas, SPAs), collectively referred to as Natura 2000 or European sites. Under Article 6(3) of the Habitats Directive, any plan or project which is not directly connected with or necessary to the management of a European site but would be likely to have a significant impact on such a site, either individually or in-combination with other plans and projects, shall be subject to an appropriate assessment of its implications for the European site in view of the site s conservation objectives. The Habitats Directive applies the precautionary principle to these sites and projects can only be permitted when it is ascertained that there will be no adverse impact on the integrity of any European-designated site(s). Where adverse impacts are identified a project may only be permitted in the absence of alternative solutions if there is an Imperative Reason of Overriding Public Interest (IROPI) for the project to go ahead. Where this is the case, Member States are required to take all compensatory measures necessary to ensure that the overall coherence of the Natura 2000 network is protected. For offshore areas ( nautical miles (nm) from the coast) the requirements of the Habitats Directive are transposed through the Offshore Marine Conservation Natural Habitats Regulations (2007) as amended. In accordance with these Regulations, the impacts of a project on the integrity of a European site are assessed and evaluated as part of the Habitat Regulations Appraisal (HRA) process. Relevant information required for the HRA process is provided in Chapter 5. In an analogous process, the Marine (Scotland) Act and the Marine and Coastal Access Act require the potential for significant risk to the conservation objectives of Nature Conservation Marine Protected Areas (NCMPAs) and Marine Conservation Zones (MCZs) respectively, to be assessed. As for the HRA process, the relevant information is presented in Chapter 5. The Scottish Government adopted the National Marine Plan in early 2015 (Scottish Government, 2015) to provide an overarching framework for marine activity in Scottish waters, with an aim to enable sustainable development and the use of the marine area in a way that protects and enhances the marine environment whilst promoting both existing and emerging industries. This is underpinned by a core set of general policies which apply across existing 31

32 and future development and use of the marine environment; policies of particular relevance to the Liberator Phase 1 Field Development include: General planning principle: There is a presumption in favour of sustainable development and use of the marine environment when consistent with the policies and objectives of the Plan; Economic benefit: Sustainable development and use which provides economic benefit to Scottish communities is encouraged when consistent with the objectives and policies of this Plan; Natural heritage: Development and use of the marine environment must: o Comply with legal requirements for protected areas and protected species. o Not result in significant impact on the national status of Priority Marine Features. o Protect and, where appropriate, enhance the health of the marine area. Noise: Development and use in the marine environment should avoid significant adverse effects of manmade noise and vibration, especially on species sensitive to such effects; Air quality: Development and use of the marine environment should not result in the deterioration of air quality and should not breach any statutory air quality limits; Engagement: Early and effective engagement should be undertaken with the general public and interested stakeholders to facilitate planning and consenting processes; and Cumulative impacts: Cumulative impacts affecting the ecosystem of the Marine Plan area should be addressed in decision-making and Plan implementation. Sectoral policies are also outlined in the Plan where a particular industry brings with it issues beyond those set out in the general policies. Specifically for the Liberator Phase 1 Field Development, oil and gas objectives and policies are of relevance; these are detailed in Chapter 7, along with comment on the degree to which the Project is aligned with such objectives and policies. 1.6 The Key elements of this ES include the following: A non-technical summary of the ES; Description of the background to the Project; role of the EIA and legislative context (this chapter); Description of the Project and alternatives considered (Chapter 2); Description of the environment and identification of the key environmental sensitivities which may be impacted by the Project (Chapter 3); 32

33 Description of the methods used to identify and evaluate the potential environmental impacts, including consultation undertaken during the EIA (Chapter 4); Detailed assessment of key potential impacts, including assessment of potential cumulative and transboundary impacts (Chapter 5); Description of the environmental management measures (Chapter 6); and Conclusions (Chapter 7). The ES is submitted to The Offshore Petroleum Regulator for Environment and Decommissioning (OPRED), part of the Department for Business, Energy and Industrial Strategy (BEIS) to inform the decision on whether or not the Project may proceed, based on the residual levels of potential impact. This ES is subject to formal public consultation. 33

34 2 Project Description 2.1 Consideration of Alternatives Process The development option selection for the Liberator Phase 1 Field Development was based on minimising environmental, health and safety, technical, Project execution and commercial risk and impact. Although the Project EIA doesn t commence until later in the design process, environmental considerations were part of the concept selection process. Well selection strategy Well engineering studies demonstrated that two drill centres were optimal for the Project, balancing drilling cost and risk against subsea infrastructure costs. The subsurface work programme demonstrated that two wells, one at each drill centre, provided the optimum reserves recovery solution. Review of the nearby offset well 3 designs showed that the most common well architecture was a slim hole design consisting of a 30 conductor, 13⅜ surface casing and 9⅝ production casing. An alternative full hole design incorporating a 20 surface casing was also considered. Review of existing slim-hole and standard offset wells records indicated that the slim-hole design would allow wells to be drilled with fewer formation stability issues whilst drilling the long open-hole sections. The option of drilling traditional wells using a closed circulating system was also considered, but this option was associated with increased safety risks and increased time and cost due to the requirement to handle additional large diameter tubing and undertake more pipe trips. It was therefore decided to select a slim hole design using pump and dump (meaning drilling fluids would be displaced to the seabed) as a mitigation method if wellbore instability is encountered. Using a slim-hole design instead of a traditional design should result in less chance of wellbore instability, and therefore less chance of additional material needing to be circulated out of the hole onto the seabed. When compared to a traditional full returns well, the slim-hole design generates a smaller volume of cuttings and requires less drilling mud and cement to be used. If the borehole stability model shows that the formation stability risk is greater than has been assumed, the well design will require further analysis. i3 Energy is considering using gas lift to assist in maintaining production rates once the fluid column in the wells is no longer able to flow at sufficient rates naturally (possibly after around 3 years) or if the wells are no longer able to re-start naturally after any shutdown. Gas lift is already provided by the Bleo Holm FPSO to the adjacent Blake wells, and the L1 and L2 wells will have appropriate internal valving and pipework installed to allow lift gas to be delivered if required. 3 Offset wells are existing wells close to the proposed drilling location that can provide information on subsurface geology and pressures. 34

35 Selection of processing facilities Early in the screening process for processing facilities, two options were identified as viable for the Liberator Phase 1 Field Development: Option 1: Wells to be tied in to the Blake manifold with fluids produced to the Bleo Holm FPSO for processing; Option 2: Wells to be tied in to a new subsea manifold with fluids produced to a new FPSO for processing. Following review of the options against i3 Energy technical and commercial screening criteria, it was determined that the preferred option was Option 1. This option was thus approved by the i3 Energy Board of Directors and is presented as the selected option in this ES. Selection of pipeline specifications and routes Options for the location of the second well were evaluated with the technical risk of drilling the western extremity of the reservoir from the Blake manifold being compared to the additional cost and impact of drilling from a technically more secure location 2 km to the west. After careful evaluation, the western location was calculated to present the most efficient and highest chance of drilling success. The pipeline from the second well is planned to run directly to its tie-in point close to the first well. The line will be buried throughout the majority of its length with concrete mattressing protecting the exposed sections near the tie-in points at each end of the line. 2.2 Drilling Description Nature of reservoir The Liberator field is located 1 km west of the Blake Channel Field and shares the same high quality Captain sand reservoir, oil type, and initial oil water contact. The reservoir quality of the Captain sandstone is exceptional, with an estimated 95% of the reservoir producing economically recoverable oil, an average porosity of 30% and permeability in the 2,000 3,000 m depth range. In the area beyond the Liberator field, the Captain channel is oriented NNW- SSE and is around 3 km wide. The Liberator field is an elongated NW-SE reservoir with an expected maximum oil column of approximately 80 feet above the oil water contact. An extension of the Liberator reservoir, named Liberator NE lies just 1.5 km to the north within the same Captain sand channel. The Liberator reservoir will be developed with horizontal wells (meaning the producing parts of the wells will be orientated horizontally or near-horizontally) and will be produced under a combination of natural reservoir pressure and the ongoing water injection from the nearby Blake field. The Liberator reservoir and extension are estimated to contain over 56 million standard barrels (MMstb) of oil in place. The Liberator Phase 1 Field Development is planned to recover approximately 20 MMstb of oil. 35

36 Fluid samples from the Liberator field exhibit 30.3 degrees gravity on the American Petroleum Institute scale, with a low Gas-to-Oil Ratio; fluids are of identical quality to that of the Blake Field. The Liberator field is underlain by a massive and very high quality aquifer which supports production from a number of fields in the Outer Moray Firth area. Reservoir pressure will remain sufficiently close to original pressure for production to continue without the need for water or gas injection. Drilling strategy Liberator will be developed by the drilling of two wells, L1 and L2. L1 will be drilled close to the existing Blake manifold and tied back via rigid spool pieces, which may be stored on the seabed temporarily during installation. Spools for the L1 well would be stored within the existing 500 m safety zone around the Blake manifold. L2 will be drilled approximately 2 km west of the Blake manifold and tied back to the manifold via a trenched and buried 2 km rigid or flexible pipeline and control umbilical and associated spool pieces. Drilling of the Liberator wells is expected to commence in April 2018 and be completed by the end of June Vertical seismic profiling (VSP) VSP is included as contingency only and will only be used if it becomes apparent during drilling that the reservoir conditions are significantly different from what is expected. It will be known if VSP is required once approximately 2,500 ft (762 m) of the final, horizontal well section has been drilled. If VSP is required, a geophone (noise detector) would be conducted into the hole on drill-pipe and an air-gun (noise source) would be suspended in the water below a support vessel. The geophone would be run into the hole and periodically locked against the side of the wellbore to record impulses from the air-gun. For the vertical part of the well, the support vessel would be located next to the rig. As the well deviates from vertical, the vessel would track above it to ensure the source remains in the vertical position above the geophone in the well. It is expected that up to 25 stations would be required, with one shot fired per station. VSP operations are expected to take up to 36 hours per well. Drill rig The drilling rig used will be a semisubmersible unit. The likely option is the Ocean Guardian (Figure 2-1), which will make use of an eight chain anchor pattern to remain in a fixed position whilst drilling. If this rig is specific unavailable, a rig of similar anchoring specification will be used (i.e. rigs will not hold station using dynamic positioning). The drill rig will carry a blowout preventer (BOP) which will be installed on the wellhead when drilling with a riser in place and during well completion and testing. The function of the BOP is to prevent uncontrolled flow from the well by closing in the well at the seabed if required. The BOP is made up of a series of hydraulically operated rams that can be closed in an emergency from the drill floor and from a safe location elsewhere on the drill rig. 36

37 Figure 2-1 Image of the Ocean Guardian (Diamond Drilling, 2015) Well design The Liberator reservoir is expected to be uniform in nature and the two wells will therefore be of a similar design. Liberator will be developed initially by a single horizontal production well (L1) drilled from the vicinity of the Blake production well cluster and deviated to land in the Liberator reservoir approximately 12.2 m (40 ft) above the oil water contact. It is intended to complete a 1,128 m (3,700 ft) horizontal section in the reservoir. Sand screens will be installed across the reservoir section to prevent sand entering the wellbore whilst allowing fluids to flow, and a simple flow control system may be installed to encourage flow from the toe of the well (the very end of a horizontal well) initially. Table 2-1 provides the diameter, length and drilling rate for the Liberator wells whilst Figure 2-2 shows the expected well design. Table 2-1 Expected parameters for the Liberator wells Well section Drilling parameter Diameter (inches) ½ 12 ¼ 8 ½ Length (feet) 232 2,985 4,470 4,297 Length (m) ,310 Drilling rate (m per hour)

38 STRATIGRAPHY STRAT DEPTH CASING DESIGN INC COLUMN TOPS Formation (Not to scale) TVDRKB MDRKB MD-RKB MSL Mean Sea Level 83 ft 83 ft 83 ft Sea bed 0 30" ft Dornoch 1470 ft 1470 ft Lista 2262 ft 2267 ft 13 3/8" casing 2,140 ft Maureen 3054 ft 3078 ft Ekofisk 3351 ft 3387 ft Tor 3549 ft 3596 ft 3,640 ft 13 3/8" /8" casing 6,610 ft Hidra 4839 ft 5151 ft Top Completion Rodby 5029 ft 5502 ft 7,970 ft /8" Captain 5300 ft 8083 ft 8,110 ft /2" Sandscreen Well 12,945 ft 90 Figure 2-2 Liberator well casing design 38

39 Mud system and cuttings Muds used to drill the various hole sections of a well have a number of functions, including: Maintenance of downhole pressure to avoid formation fluids flowing into the wellbore (also called a kick ); Removal of drill cuttings from the drill bit to permit further drilling and transporting cuttings to the surface cuttings handling equipment; Lubricating and cooling the drill bit, bottom hole assembly and drilling string; and Deposition of an impermeable mudcake on the walls of the well bore, which seals and stabilises the open hole formations. Drilling fluids can consist of various materials including weighting agents and other chemicals to achieve the required weight, viscosity, gel strength, fluid loss control and other characteristics to meet the technical requirements of drilling and completing the well. Generally, drilling fluids can be divided into two categories based on their base fluid types: Water-based mud (WBM), where the base fluid is water; and Oil-based mud (OBM), where the base fluid is an emulsion of water droplets distributed within an oil (includes low toxicity oil based mud). Various chemicals can be added to either type of drilling fluid to achieve specific results, which are mainly driven by formation pore pressures and fracture gradients, downhole temperatures, geological characteristics etc. Different types of mud are planned to be used for different well sections. The top two sections (36" and 17½") will be drilled open-hole, without a riser in place. Seawater and regular bentonite sweeps will be pumped downhole to aid cuttings removal and keep the hole clean. Cuttings from these sections will be discharged directly to the seabed. Subsequent sections will be drilled with a riser in place, meaning mud and cuttings will be returned to the drilling rig topsides, where they will be separated from the mud using shale shakers so that the mud can be re-used. The 12¼" section will be drilled with either WBM or low toxicity oil based mud (LTOBM). If WBM is used, the separated cuttings will be discharged overboard. If LTOBM is used, separated cuttings will be stored in skips and shipped to shore for treatment and disposal. The 8½" section will be drilled with WBM, with separated cuttings discharged overboard. Table 2-2 details the drilling mud requirements for one well; the requirements for L1 and L2 are expected to be the same. It is assumed that WBM will be used for all sections as this is a worst case in terms of discharges to sea (i.e. LTOBM would not be discharged to sea if used). 39

40 Table 2-2 Estimated tonnages of drilling mud components per well Mud/fluid (name) Component Discharges per section 30" 17½" 12¼" 8½" Seawater KCl WBM KCl glycol KCl with sweeps WBM WBM Bentonite (t) Barite (t) Calcium carbonate (t) Total mud discharges for one well (t) Total cuttings discharges for one well (t) Total discharge for one well 4 (t) 1,500 4,700 3,500 3,000 Cementing and other chemicals Steel casings will be installed in each well section to provide structural strength to support the subsea trees, isolate unstable formations and different formation fluids and separate different wellbore pressure regimes. Each steel casing will be cemented into place, which will provide a structural bond and an effective seal between the casing and surrounding rock formation. During cementing operations, excess cement may be pumped, which would be discharged to sea. To limit unnecessary discharge of cement, it is anticipated that all cement will be mixed as required, but as a worst-case for this assessment it has been assumed that, for each well, up to 60 m 3 (108 tonnes) of cement could be discharged to sea (under the relevant chemical permit). All chemicals to be used within the cement will be selected based on their technical specifications and environmental performance. Chemicals with substitution warnings (i.e. those identified by UK authorities as requiring phase out over time) will be avoided where technically possible. The cementing chemicals to be used have not yet been determined but will be selected using the well operator s chemical management and selection policy. Chemicals to be used during well completion (the point at which the downhole equipment is assembled to enable production from the well) will be limited to a maximum of 70 m 3 of sodium chloride (NaCl) brine per well. Well testing and clean up Prior to production, both wells will be cleaned up to remove any waste and debris and prevent damage to the pipeline or topsides production facilities. Well tests may then be conducted to obtain reservoir information and fluid samples. Fluids produced from well testing will flow 4 This includes PLONOR substances, added substances and water. PLONOR substances are those on the OSPAR List of Substances/Preparations Used and Discharged Offshore which are considered to Pose Little or No Risk to the environment. 40

41 back to the semi-submersible drilling rig. The likely sequence of events for well testing and clean-up will be as follows: Open well and flow; Capture and test water/hydrocarbon interface fluids. If oil in water concentration is equal to or below 30 mg/l, discharge fluid overboard in accordance with the oil discharge permit that will be in place. If oil in water concentration is above 30 mg/l, filter fluids until they are below 30 mg/l for overboard discharge; Monitor and record the amount of water and suspended solids in the produced fluids to calculate the basic sediment and water specification; Flow well for a test period of up to 96 hours; and Close well in, ready for production. During well clean up and testing, up to 2,000 tonnes of oil may be produced per well. Oil produced during well testing will be flared over a maximum period of 96 hours. Any gas produced during well testing will also be flared; flared gas is not expected to exceed 200 tonnes per well. Well suspension Well L2 is likely to be drilled and subsequently suspended in line with Oil and Gas UK guidelines. Once the subsea pipeline and umbilical are installed, the well will be re-entered and production from the well will commence. Well workovers and interventions The Liberator wells have been designed with a minimum planned intervention philosophy for the anticipated seven year life of the wells. However, it is recognised that remedial well interventions could be necessary in the case of equipment failure. In this case, wireline intervention using a slickline or electrical cable to lower tools into the well may be performed from a light well intervention vessel (this is a smaller vessel than a traditional semi-submersible drill rig or ship). Coiled tubing intervention, where a long metal pipe instead of an electrical cable is used, would require a semi-submersible drill rig. 2.3 Subsea An overview of the proposed subsea layout is shown in Figure 2-3. Further detail on each of the components is given in the subsequent sections of this chapter. Installation of subsea structures, pipeline and umbilical is expected to commence in July 2018 and to be completed in August

42 Figure 2-3 Liberator field layout schematic Subsea trees, designed to control flow will be installed on top of the wellheads by the drilling rig. The subsea tree is the main barrier between the reservoir and the environment, and also provides a mechanism for flow control and well entry. All wells will have a sub-surface safety valve installed which is an isolation device that is hydraulically operated and fail-safe closed. During completion operations, the subsea trees will be controlled from the drill rig, whilst during production the subsea trees will be remotely controlled from the Bleo Holm FPSO via control umbilicals. Hydraulic fluid will be the same as is currently used in the Bleo Holm control system. The trees on both wells will incorporate an SFF approved fishing-friendly tree protection structure able to resist the bollard pull (pulling force) generated by potential fishing gear interactions whilst posing minimal risk to fishing vessels. Including the protection structures, each tree will have a seabed footprint of 7.87 m x 7.87 m and have a height above the seabed of 5.08 m. 2.4 Pipeline and Umbilical New pipeline A 6" production pipeline of approximately 2 km length will run between L2 and the L1 well, where it will be tied in using a spool. This pipeline will transport produced fluids from Well L2 to the L1 tie-in spool, and onward to the Bleo Holm FPSO. There is no requirement for a new pipeline for Well L1, whose production will tie directly into the existing Blake manifold by way of a production spool of approximately 100 m length. 42

43 A subsea multi-phase flowmeter will also be installed either just downstream of the tie-in point of the L2 well into the L1 production spool or just upstream of the Blake production manifold. This meter will be used to determine the total fluid flow from the Liberator Phase 1 Field Development being delivered to the Blake subsea facilities. Power and signals to and from the subsea multi-phase flow meter will be provided using the L1 control umbilical or by direct connection to the Blake subsea manifold. Umbilical requirements A 4.5" control umbilical of approximately 2 km length will run between L2 and L1, where it will tie into the control jumper that will be installed between L1 and the Blake manifold. The umbilical will deliver the chemical, electrical, control and communications services from the Bleo Holm FPSO via the Blake manifold to Well L2. A short 4.5" umbilical of approximately 100 m length will be installed between the L1 well and the Blake manifold. Gas lift i3 Energy is considering injecting gas at high pressure into the base of the wells to mix with the produced hydrocarbons. This inflow of gas has the effect of reducing the density of the fluids, assisting with their delivery to the top of well. If the decision is made to use gas lift, a gas lift spool of approximately 100 m length will be installed on the seabed between the Blake manifold and Well L1. A steel pipeline of 2" or 4" diameter will run between Well L1 and Well L2, being installed in the same trench as the umbilical. Seabed preparation Geophysical and geotechnical survey has been carried out along all pipeline and umbilical routes and the routes will be finalised prior to installation, taking into account any seabed features that could obstruct or impede installation. A pre-lay remotely operated vehicle (ROV) survey will be carried out prior to installation to determine whether any new obstructions have appeared. During installation, boulders may need to be moved outside of the pipeline and umbilical corridors. Pipeline and umbilical lay It is anticipated that the pipeline and umbilical (and gas lift line if required) will be laid in two separate trenches using a water jet and allowed to naturally backfill with soil (Figure 2-4). Water jet trenching involves directing jets of water into the sediment in order to fluidise the sediment and allow the pipeline to sink through the sediment slurry into the bottom of the trench. Trenches are expected to be separated by approximately 50 m. Further work will be undertaken to determine if the pipeline and umbilical can be laid in the same trench. At the ends of the trenches, the pipeline and umbilical will come out onto the seabed by way of an open sloped end to the trench (the trench ends will be protected with mattresses). Production spools and jumpers will cover the untrenched distances (approximately 100 m at each end) between the ends of the pipeline and umbilical and the tie-in points. 43

44 Figure 2-4 Illustration of likely trench and backfill method for pipeline and umbilical installation The pipeline and umbilical are expected to be laid by a reel-lay vessel (Figure 2-5). The pipeline and umbilical will be wound onto a reel (like cotton wound onto a spool) on the quayside and transferred by a reel-lay vessel to site. The end of the pipeline and umbilical will be temporarily anchored to the seabed at one end of the route, either at the Blake manifold or at Well L2, and the reel-lay vessel will move off. The pipeline and umbilical (whichever is being installed at that point) unwinds from the reel on the vessel, passes down through the water column, and comes to rest on the seabed. The installation vessel position will be controlled by dynamic positioning (DP) and will not require anchors. Figure 2-5 Illustration of a reel lay vessel in operation Tie-in installation A dive support vessel (DSV) will carry out the installation of the spools and jumpers used to tie the pipeline and umbilical in at each end. The entire 100 m length of each of the spools and jumpers cannot be lifted from the DSV in one go, so shorter sections will instead be transferred by vessel crane to the seabed. Divers will connect the sections of spool or jumper together. Once the spools and jumpers are installed, concrete mattresses (such as shown in Figure 2-6) will be placed along the length of the spools and jumpers to both provide protection and ensure they remain in place. Approximately three production spools (two at Well L1 and one at Well 44

45 L2) and three jumpers (two at Well L1 and one at Well L2) each 100 m in length will require protection, which equates to approximately 100 mattresses. If gas lift is determined to be required, three further spools of 100 m length each will be installed, with a further approximately 50 mattresses installed.. Figure 2-6 Example of a typical concrete mattress used in offshore developments (3 m x 6 m x 0.5 m) Once the pipeline and umbilical are laid, the route of each will be visually inspected by ROV to confirm its location. Pipeline and umbilical protection and crossings For the pipeline, burial will assist in protection against upheaval buckling, where temperature changes can cause the pipeline to bend and move. However, it is possible that targeted rock placement will be needed at specific locations in order to ensure the pipeline remains within the trench. If rock placement is required, the arrangement of rock cover is likely to be similar to the illustration shown in Figure 2-7. For the purposes of this assessment, it has been assumed that five locations will require treatment, each with berms 20 m long and 2 m wide. Figure 2-7 Example of possible likely targeted rock placement for mitigation of upheaval buckling 45

46 The pipeline and umbilical (and the gas lift line, if installed) from the L2 well will require to cross the Blake to Ross main field flowlines and umbilical. These consist of three trenched corridors containing a 16" production pipeline and umbilical in one trench, a 12" production pipeline in one trench and a 12" water injection and 6" gas lift pipeline in the third trench. These crossings will be protected by construction of simple approximately eight spot rock berms of approximately 10 m x 5 m (and 1 m height) that will elevate the L2 flowline, umbilical and gas lift line over them. Rock will then be placed on the L2 flowline, umbilical and gas lift flowline to provide protection. This overtrawlable construction is illustrated in Figure 2-8. It is possible that a combination of mattresses and rock will be used (as shown in Figure 2-3), but such an arrangement would occupy the same footprint as a solution that involved only rock. Figure 2-8 Example of likely rock placement for crossings Pipeline and spool pre-commissioning In advance of the production pipeline being readied to carry produced fluids, a series of precommissioning activities will be undertaken. i3 Energy expects that the pipeline and production spools will be pressure- and leak-tested together once installed using seawater treated with biocide, corrosion inhibitor and oxygen scavenger. The pipeline and production spools will then be de-watered (fluids will be pushed to the Bleo Holm FPSO for treatment in the produced water system) and filled with glycol, ready for production from the wells. In total, it is expected that up to 312 m 3 of treated seawater will be passed from the Liberator production system to the Bleo Holm FPSO for treatment and discharge. If the gas lift line is installed, leak testing will be carried out prior to the line being made operational. Nitrogen gas will be injected into the pipeline (most likely from the Bleo Holm FPSO and the pressure recorded at set intervals, to ensure there is no loss of the gas (which would indicate a leak). Umbilical pre-commissioning The hydraulic cores of the umbilical and jumpers will be filled with hydraulic control fluid prior to operation. The hydraulic fluid will remain in the umbilical and jumper cores during operation of the Liberator field, with small, intermittent discharges of up to 10 l occurring during opening and closing of the hydraulic valves (these valves are opened and closed to start and stop the flow of chemicals into the well/produced fluids). Although the hydraulic fluid has not yet been selected, it will be water-based and biodegradable and used under appropriate chemical permit. 46

47 The chemical cores of the umbilical and three jumpers will be filled prior to operation. Chemicals will remain in the umbilical cores until operation commences, at which point they will be used to treat the produced fluids, entering the Bleo Holm process system for discharge with produced water over the field life of seven years. Although the chemicals have not been specifically identified at this point, production chemicals typically include hydrate inhibitor (such as methanol) to stop solids forming within the fluids, corrosion inhibitor to maintain integrity of the production pipeline and scale inhibitor to prevent build-up of solids on the internal surfaces of the production pipeline. Operations and maintenance The hydraulic valve system on subsea infrastructure may incorporate a discharge to sea system, which could mean some fluid being discarded when valves are opened and closed. Such hydraulic fluid is expected to be water-based and biodegradable. During its anticipated seven year operational lifetime, the pipeline and umbilical will be subject to a number of inspections to ensure continued integrity. External inspection will be carried out using a combination of ROV/autonomous operated underwater vehicle and towed sonar. The frequency of such maintenance will be determined by ongoing risk assessment. The pipeline has been designed to allow for operational pigging 5, but this is not expected to be required. 2.5 Host Modifications Pipework, spools and umbilicals from the combined L1 and L2 wells will be tied in to existing flanges on the Blake manifold. At present the assumption is that there is no requirement to make modifications to the Blake manifold other than installing suitable isolation valves at the pipeline connection points. No other modifications are anticipated to any of the other existing infrastructure associated with the Blake field or the Bleo Holm FPSO. The seven year field life anticipated for the Liberator Phase 1 Field Development will not require the Bleo Holm FPSO to remain on site longer than is currently approved. 2.6 Production Production profiles Production will come online in 2018, with approximately 9,560 barrels (1,091 tonnes 6 ) of oil and 70,400 Sm 3 of gas produced per day. Production will peak in 2020 at approximately 15,600 barrels of oil (1,990 tonnes) and 105,300 Sm 3 of gas per day, before steadily declining over the remainder of the projected field life of seven years. The predicted combined production profile for the Liberator field is presented in Table 2-3, Figure 2-9 and Figure Figure 2-11 shows the projected Liberator oil production stacked on top of the existing permitted Bleo Holm production throughput (from the Ross and Blake fields), illustrating that the Liberator field coming online will result in an increase in Bleo Holm 5 Pigging is when a structure called a pig is forced through the pipeline to clean and inspect the internal surfaces. 6 Oil conversions calculated using i3 supplied conversion factor of stb per tonne. 47

48 production throughout the seven year life of the Liberator Phase 1 Field Development. The production profiles presented herein are the highest predictions (called P10 ). Daily production is averaged for each calendar year presented. Table 2-3 Liberator Phase 1 Field Development production figures (P10, or high case) Year Oil rate (t/d) Gas rate (Sm 3 /d) Water rate (m 3 /d) ,331 70, , , , , ,670 88, ,401 74, ,176 62, , ,500 Oil production (tonnes/day) 2,000 1,500 1, Year Figure 2-9 Liberator Phase 1 Field Development oil production profile 48

49 140, ,000 Gas production (Sm 3 /day) 100,000 80,000 60,000 40,000 20, Year Figure 2-10 Liberator Phase 1 Field Development gas production profile 4,000 3,500 Oil production (tonnes/day) 3,000 2,500 2,000 1,500 1, Year Bleo Holm oil production (t/day) Liberator oil production (t/day) Figure 2-11 Liberator Phase 1 Field Development oil production in the context of existing Bleo Holm production 49

50 Produced water Produced water will be treated in the existing system of the Bleo Holm FPSO and either reinjected into the Blake reservoir or treated to reduce the oil content below the regulatory limits (see below) and discharged overboard. On the basis of the high case oil and gas production estimates, water production from the Liberator wells is expected to increase from 7 m 3 /d in 2018, peaking at 584 m 3 /d in 2024 (Figure 2-12). Whilst produced water from the Liberator Phase 1 Field Development will increase the overall produced water volume handled at Bleo Holm, produced water from the Liberator Phase 1 Field Development will represent only between 0.15 and 9.0% of produced water processed by the FPSO. The total produced water processed at the Bleo Holm FPSO will be within the existing capacity of the system (up to approximately 15,900 m 3 per day), with no modifications to the system required. 8,000 7,000 Liberator Bleo Holm Water rpoduction (m 3 /day) 6,000 5,000 4,000 3,000 2,000 1, Year Figure 2-12 Liberator produced water profile in the context of produced water processed by Bleo Holm (from fields other than Liberator) The following regulatory requirements will continue to be met at Bleo Holm once Liberator production is brought on line: The use and/or discharge of all production chemicals will be subject to risk assessment and permitting under the Offshore Chemicals Regulations; Oil in water discharge via the produced water system will be within the existing approved limits, which currently include: o A maximum monthly average of oil (dispersed) in water content of 30 mg/l or less; o A maximum daily measurement of 42 mg/l; and o The maximum concentration not to exceed 100 mg/l at any time. 50

51 Power generation, venting and flaring Production at the Liberator field will slightly increase the overall power requirement at Bleo Holm, resulting in increased fuel use. This has been assumed to be an increase in fuel use of 10% from historical fuel use at Bleo Holm. The historical and expected fuel use figures are detailed in Table 2-4. Table 2-4 Fuel use required to process Liberator produced fluids in the context of historical and forecast fuel use at the Bleo Holm FPSO Bleo Holm fuel use Liberator fuel use Total fuel use Year (tonnes) (tonnes) (tonnes) ,249 N/A 19, ,567 N/A 22, ,098 N/A 20, ,908 1, , onwards 8 20,908 2,091 22,999 Apart from the base load flare required for the safe and efficient operation of the process and flare systems under normal operating conditions, gas is flared on Bleo Holm only during emergency pressure relief, during periods of process instability typically after start up and shut down, or for brief periods during unavailability of the gas compression system. The production from the Liberator field will not significantly change the current operating conditions at Bleo Holm with respect to flaring. There will be no additional routine flaring associated with processing of Liberator fluids, the gas will be processed along with Blake and Ross produced gas to export quality from start-up. The Bleo Holm installation does not currently vent gas and there will be no changes to this venting requirement as a result of Liberator production. 2.7 Vessel Requirements The vessels expected to be involved in the drilling, installation, commissioning and operation of the Liberator field are described in Table 2-5. Helicopters will also be required for transportation of personnel during installation and commissioning, and it is estimated that 58 flights will be required during the period it takes to drill and complete both wells. There will be no additional ongoing operational helicopter requirement beyond current demand at Bleo Holm as a result of Liberator production coming on stream. 7 Assumed to be for a maximum of 6 months of the year only. 8 These are the assumed annual totals for 2019 onwards for the life of the Liberator field. 51

52 Table 2-5 Estimated vessel types and number of days 9 required for the Liberator Phase 1 Field Development Drilling Drilling Operation Vessel type Number of days Semi-submersible drilling rig Anchor handling Anchor handling vessel 138 Emergency response and rescue (ERRV) Safety vessel 121 Supply Supply vessel 181 Subsea installation Pre-lay survey Survey vessel 4 Survey and light construction vessel support Survey vessel 4 Pipelay Pipelay vessel 9 Umbilical and gas lift line lay Pipelay vessel 6 Pipeline trenching Trenching vessel 6 Umbilical and gas lift line trenching Trenching vessel 3 Tie-in DSV 10 Rock placement for mitigation of upheaval buckling Lay mattresses and commissioning activities Rock vessel placement 17 5 DSV 9 Guard vessel Guard vessel 20 Operation Inspection and maintenance of subsea structures Survey vessel 15 days 10 over seven years 9 Includes mob/demob, transit and working time. 10 The frequency of inspection and maintenance will be defined as part of the Pipeline Integrity Management System process. However, for the purposes of this impact assessment, it has been assumed that one survey lasting three days will occur shortly after production and every two years thereafter for a maximum of 7 years (i.e. until predicted end of field life). 52

53 2.8 Decommissioning Once production from the Liberator field becomes irrevocably uneconomic, permission will be sought for production to cease. Decommissioning of oil and gas facilities in the UK is regulated under the Petroleum Act 1998, as amended by the Energy Act The UK s international obligations on decommissioning are governed principally by the Oslo-Paris Convention for the Protection of the Marine Environment of the North-East Atlantic (OSPAR Convention). DECC s Guidance on the Content of Offshore Oil and Gas Field Development Plans states in accordance with the UK's international obligations, all installations emplaced after 9 February 1999 must be completely removed to shore for reuse, recycling or final disposal on land. DECC (2011) provides specific guidance on decommissioning activities; Figure 2-13 shows the process leading to approval of a decommissioning programme. The DECC (2011) guidance is currently being updated by BEIS. At the onset of the decommissioning phase i3 Energy will adhere to the decommissioning guidance that is current at the time. Figure 2-13 Decommissioning approach The two production wells will be plugged and abandoned at the end of field life (anticipated to be seven years). It is likely that cement plugs will be set across the reservoir sections, across casing shoes and in the conductor casing, and that the conductor casing will be cut below the seabed. The well abandonment will follow legislation and guidelines applicable at the time. i3 Energy will recover the spools and any supporting structures (e.g. mattresses) at the end of field life. The OSPAR provisions do not apply to pipelines; however, DECC (2011) guidance sets out UK policy on pipeline decommissioning. The decommissioning strategy for the pipeline and umbilical will depend on a number of factors including, the availability of suitable technology and the potential environmental, safety and cost implications of decommissioning methods at the end of field life, approximately seven years after production commences. The ultimate intention is to leave the seabed of the development area in such a condition that it will pose no risk to the marine environment or to other sea users, and the development has been designed with this intention in mind. No development decisions have knowingly been taken that will preclude this goal. Prior to the end of field life there may well be changes to the statutory decommissioning requirements as well as advances in technology and knowledge. i3 Energy will aim to utilise recognised industry standard environmental practice during all decommissioning operations in line with the legislation and guidance in place at the time of decommissioning. Discussions on 53

54 what may be required will be held with the Regulator as early as possible before decommissioning commences. Prior to the decommissioning process, re-use and recycling alternatives will be considered where feasible to reduce the potential for materials having to go to landfill. In advance of the decommissioning process an inventory of Project equipment will be made and the potential for further reuse will be investigated. As an integral component of the decommissioning process, i3 Energy will undertake a study to comparatively assess the technical, financial, health, safety and environmental aspects of decommissioning options, for which a further EIA may be required. Responsibility for decommissioning the Blake manifold, the pipelines and umbilicals between the Blake manifold and the Bleo Holm FPSO, and the Bleo Holm FPSO itself will remain with the Blake field Operator (currently Repsol Sinopec) and the FPSO owner (currently Bluewater). 54

55 3 Environmental Description 3.1 Introduction This section describes the main characteristics of the offshore environment in the vicinity of the Liberator field, with particular attention being given to those aspects that may be sensitive to, or affected by, the proposed operations. This description draws on a number of data sources including published papers on scientific research in the area and site-specific studies. i3 Energy has conducted a new environmental baseline and habitat survey in summer As the survey has only recently been completed, analysis of samples collected has not yet been undertaken and the preparation of the environmental baseline and habitat assessment reporting is still ongoing. As such, the results of the survey were not available to inform this EIA. However, i3 Energy and survey environmentalists have together reviewed the initial survey data and consider the initial results to support the habitat definitions given by the previous survey work that serves as the basis for the benthic assessment. 3.2 Physical Environment Weather and sea conditions The anti-clockwise movement of water through the North Sea and around the CNS region is driven largely through the influx of water from the Atlantic, entering the northern North Sea (NNS) north of Shetland and via the Fair Isle Channel, and the main outflow northwards along the Norwegian coast. This inflow from the Atlantic flows south along the Scottish and English coasts, with offshoot currents heading off east across the North Sea. Against this background of tidal flow, the direction of residual water movement in the CNS is generally to the southeast (DTI, 2001a). Offshore tidal current velocities in the region are relatively consistent between 0.5 knots and 1.0 knots (0.25 to 0.51 m/s) during mean spring tides (BODC, 1998). Historical Meteorological Office wind data for the CNS region ( ) show that winds are dominated by those from the south south-west and south, although they can occur from all directions. Speeds throughout the year equate to moderate to strong breezes (6-13 m/s) on average, with speeds frequently reaching in excess of 17.5 m/s between November and March (DTI, 2001a).The average wave height in the CNS region follows a gradient decreasing from the northern area of the Fladen/Witch Ground to the southern area of the Dogger Bank. In the North the mean wave height ranges from m whilst in the south it ranges from m. Wave heights remain low ( m) along the CNS coastline (NMPI, 2017). McBreen et al. (2011) shows wave energy at the seabed at the Liberator location to be low (<1.2 N/m 2 ) and tidal streams to be defined as low (<0.5 m/s). The average mean significant wave height in the vicinity of the Liberator field ranges from 1.81 to 2.1 m whilst the annual mean wave power ranges from 18.1 to 24 kw/m (NMPI, 2017). Bathymetry and seabed conditions The North Sea is a large shallow sea with a surface area of around 750,000 km 2. Water depths gradually deepen from south to north (between approximately 40 m at the Dogger Bank and 100 m at the Fladen/Witch Ground (DTI, 2001a). The main topographic features in the CNS are the Dogger Bank, a large sublittoral sandbank submerged through sea-level rise located in the south-west corner of the region, marking a division between the southern North Sea (SNS) 55

56 and CNS, and the Fladen/Witch Ground, a large muddy depression generally considered to define the northern extent of the CNS (DTI, 2001a). The Norwegian Trough, a deep water channel extending from the mouth of the Baltic Sea to the Norwegian Sea occurs to the east of the Norwegian/UK median line (DTI, 2001a). Seabed sediments in the CNS generally comprise a veneer of unconsolidated terrigenous and biogenic deposits, generally significantly less than 1 m thick (Andrews et al., 1990). DECC (2009) reports that sand and slightly gravelly sand covers much of the bed of the CNS region and occurs within a wide range of water depths from the shallow coastal zone to 110 m in the north and to below 120 m in isolated deeps in the centre known as the Devil s hole (DECC, 2009; JNCC, 2010). Sediments may have a significant mud content, particularly in basins and in deeper waters to the north. Coastal areas in the region support a more varied range of intertidal and seabed habitats (DTI, 2004). Recent mapped information (JNCC, 2010) indicates benthic sediments in the CNS to consist largely of sand or muddy sand, with smaller isolated areas of coarse sediment or mud and sandy mud. The seabed sediments of the Moray Firth Basin are mainly Holocene in origin, and their distribution reflects both the glacial history of the area and the present hydrographic regime. The Liberator field lies in an area of seabed which is characterised as muddy sand and sand (Andrews et al., 1990). Rig site surveys conducted by Gardline at the Liberator field in 2013 have contributed to the current understanding of the environmental baseline (Gardline, 2013a; Gardline, 2013b; Gardline, 2013c). A shallow geophysical survey was carried out covering an area of 4.5 km x 3.9 km over a total distance of km, as well as a 2D High Resolution Seismic survey which covered an area measuring 2.25 km x 2.00 km and a total distance of km (Gardline, 2013a). Single beam and multi-beam echo sounders, side scan sonar, magnetometer, pinger, sparker, environmental camera/grab and high resolution seismic equipment were used (Gardline, 2013a). The 2013 survey did not cover the site of the Blake manifold or the Liberator L1 well location. Survey data covering these sites is however available from an older site survey conducted in 2006 (Gardline, 2006). This work comprised a shallow analogue geophysical survey covering an area of 4 km x 4 km over a total distance of km and an environmental baseline and habitat assessment survey. Single beam and multi-beam echo sounders, side scan sonar, magnetometer, pinger and environmental camera/grab equipment were used. The geophysical data and the habitat assessment report prepared from this survey data is available and has been used in this report (see below). The areas covered by the Gardline (2006) and Gardline (2013a) surveys, and the area expected to be covered by new survey work planned for summer 2017 are presented in Figure

57 Figure 3-1 Summary of surveys conducted and planned in the Liberator field The water depth across the Gardline (2013a) survey area ranges from m lowest astronomical tide (LAT) in the east to m LAT in the southwest, the seabed gradient is 1.7. (Figure 3-2). The seabed is irregular across the survey area, with some prominent NNW- SSE orientated linear shoals and a large NNW-SSE orientated deep in the west, which coincides with the presence of Forth Formation sediments in the shallow subsurface. Occasional depressions 10 m to 130 m across and up to 3 m deep have been found across the survey area, the origin of these features is unknown. Increased gradients are often observed within the survey area on the edges of the seabed irregularities, with a maximum gradient of 7 on the side of the linear shoal to the west and northwest of the proposed Liberator location. No obstructions or hazards to drilling have been observed within the survey area or the 57

58 Liberator field (Gardline, 2013a). Conditions around the Blake manifold and the proposed L1 well location are similar, with water depth ranging from 86.0 m LAT m LAT and water depth broadly increasing from the southeast to the northwest of the survey area (Gardline, 2006). The seabed is irregular with shoals and depressed and elevated areas lending the seabed a hummocky appearance (Gardline, 2006). Figure 3-2 Bathymetry of the Liberator field (Note: the well locations shown in this figures are obsolete and the new well locations are shown in have now changed to those shown in Figure 3-1. Survey stations refer to those from Gardline (2013a) and not from the most recent 2017 survey work, results of which are pending) 58

59 The Gardline (2013b) environmental baseline survey consisted of capturing seabed imagery using a shallow water digital stills camera and video at 10 stations selected across the survey area using a random stratified methodology followed by the collection of four sediment samples with a 0.1 m 2 Day grab at each of the 10 stations on Figure 3.1 (Gardline, 2013b). Grab sampling observations were consistent with seabed imagery, describing samples as silty sand at each station. Particle size analysis allowed classifying particles at all stations as muddy sand under the Modified Folk Classification. Sediments were described as poorly sorted very fine sand under the Wentworth classification of mean sediment grain size, apart from station ENV5 described as poorly sorted fine sand, and stations ENV1 and ENV2 described as very poorly sorted coarse silt. It was found that fine material (<63 µm) silt and clay composed 21.1 to 41.0% of the sediment at each station, with the two highest proportions of fines recorded at stations ENV1 and ENV2, within the deepest western section of the survey area. Gravel sized material (>2 mm) accounted for a negligible <0.1% at all stations. Sediment characteristics were correlated to water depth across the survey area and overall considered representative of the expected variation in this area of the northern North Sea. Total organic matter (TOM) following removal of carbonates ranged from 0.9 to 2.2% with total organic carbon (TOC) ranging from 0.22 to 0.48% across the survey area (Gardline, 2013b). Side-scan sonar, seabed photography and particle size analysis of samples collected during the Gardline (2006) survey indicated the seabed around the Blake manifold and L1 well location is similar to that identified in Gardline (2013a). Sediments were identified as poorly sorted fine to medium slightly silty sand (Figure 3-3). An exception was identified at the south of the site where a change in seabed reflectivity was interpreted as an area where Holocene sand cover is very thin or absent and a silty clay seabed was predicted, although no samples were taken to ground-truth this interpretation. The European Environment Agency s habitat type data showed that the proposed locations for both wells are positioned in areas classified as deep circalittoral sand (EEA, 2017). A herring Clupea harengus spawning ground assessment was undertaken by Gardline at each of the stations in Figure 3-2. This revealed that the survey area was not suitable for herring spawning as the area is too deep, with strong currents and no accumulation of coarse material nor evidence of well-sorted gravels forming raised banks, which are the preferred herring spawning substrate and seabed type (Gardline, 2013c). Hydrocarbon analyses revealed concentrations largely representative of the very fine sandy sediments of the northern North Sea (NNS) with Total Hydrocarbon (THC) concentrations varying from 1.1 µg.g -1 to 4.7 µg.g -1. Mean THC concentration was comparable to or lower than the comparison Gardline (2009; 2012) surveys with all concentrations lower than the mean background threshold for the NNS (UKOOA, 2001). The total polycyclic aromatic hydrocarbon (PAH) concentrations were higher and more variable than those sampled in the previous Gardline 2009 and 2012 surveys. THC, total n- alkanes and total PAH were significantly correlated with sediment characteristics across the survey area, indicating natural variations of these compounds associated with sediment type. 59

60 Hydrocarbon concentrations were found to be typical of North Sea background concentrations and representative of the wider area by comparison with other surveys. Metals were extracted from the sediment samples for analysis, which showed levels broadly comparable with nearby surveys (Gardline, 2009; Gardline, 2012). Barium (Ba) concentrations ranged between 363 µg.g -1 and 406 µg.g -1 and were above the UKOOA (2001) mean concentration for the North Sea but within the UKOOA (2001) 95 th percentile threshold. The concentrations of Ba were comparatively lower in the deeper western part of the survey area where slightly finer sediments were recorded. All metals were within their apparent effect threshold at all 10 stations. All metals were below their background concentrations (BCs) (OSPAR, 2005) with the exception of cadmium (Cd) at stations ENV1 and ENV2. These results indicated that concentrations of As, Cd, Cr, Cu, Hg, Ni, Pb and Zn were typical of a pristine environment for these metals described by OSPAR (2005) as sites with concentrations typical of a remote, undisturbed environment. There was no evidence of gas hazard and no significant faults were observed within the survey area. Occasional boulder/debris and linear debris items were observed within the survey area. Occasional minor magnetometer anomalies were found but none lie in the vicinity of any of the debris observed on side scan sonar data. Consequently, no seabed obstructions or hazards to drilling were observed at the proposed Liberator location (Gardline, 2013b). 60

61 Figure 3-3 Seabed features within the vicinity of the Liberator location (note well location has now changed) (Gardline, 2013b) 61

62 3.3 Biological Environment Benthos The biota living near, on or in the seabed is collectively termed benthos. The diversity and biomass of the benthos is dependent on a number of factors including substrata (e.g. sediment, rock), water depth, salinity, the local hydrodynamics and degree of organic enrichment. The species composition and diversity of the benthos or macrofauna found within sediments is commonly used as a biological indicator of sediment disturbance or contamination. In order to identify macrofaunal communities during the Gardline (2013a) survey, three 0.1 m 2 faunal samples were taken at each station, two of these were analysed and one kept in storage as a spare. A total of 9,477 individuals representing 282 taxa were identified in the 20 samples analysed from the 10 stations, and 1,462 (15%) of these individuals from 38 taxa were juveniles. Juvenile brittlestars (Ophiuroidea), molluscs (Abra spp.) and polychaetes (Ampharetidae) were within the top ten most abundant records across the survey area and accounted for 63% of the juveniles dataset and 10% of the total number of individuals. Further analysis showed that the presence of a high number of juveniles did not significantly affect the measures of diversity as the full dataset (including juveniles) and the adult dataset (excluding juvenile records) were over 95% similar. Analysis of the samples revealed a fairly rich, generally evenly distributed community (Gardline, 2013c). Polychaetes were the most abundant taxa at all stations in both adult and full datasets, 73% and 66% respectively. The polychaetes Prionospio dubia, Paramphinome jeffreysii and Galathowenia oculata dominated the adult communities, and were found to be ubiquitous across the survey area, accounting for 29% of all adults identified. Dominance of polychaetes is typical from North Sea sediments where they are expected to represent at least 50% of macrofaunal species in a sample; therefore the total contribution in these samples was slightly higher than expected for the fine sandy sediment present (Gardline, 2013b). The polychaete Paramphinome jeffreysii was the most abundant species in the survey area and is considered to be tolerant to hydrocarbon contamination (Gardline, 2013c). Its abundance was considered as natural and representative of the wider area and not attributed to hydrocarbon concentrations. Galathowenia oculata was the second most abundant species found in the samples. It is commonly found in sublittoral sandy muds and is thought to be intolerant to hydrocarbon contamination. Therefore the abundant presence of this organism backs up the impression of the absence of significant contamination in the sediments sampled at the Liberator location. In addition, the presence of the polychaetes Diplocirrus glaucus and Prionospio cirrifera also indicate a low level of contaminants as these taxa are sensitive to some metals (Gardline, 2013c). Other typical species of the North Sea were abundant, such as the polychaete Owenia fusiformis and the juvenile ophiuroid brittlestars. There was no localised super-abundance of any taxa. In the full dataset, molluscs were the second most represented group followed by crustaceans and echinoderms, at all stations except stations 7 and 8 where echinoderms were present in higher numbers than crustaceans. The least abundant groups comprised sixteen taxa of which four were the phyla Sipuncula (peanut worm), three from Cnidaria (sea anemones and sea 62

63 pens), two from Chordata (Ascidiacea: sea squirt) and one each from Foraminifera, Platyhelminthes (flatworms), Nemertea (ribbon worm), Priapulida (priapulid worm), Annelida, Phoronida (horseshoe worm) and Hemichordata (Enteropneusta: acorn worm) (Gardline, 2013c). A total of 61 juveniles of ocean quahog Arctica islandica (a species of clam) was found across fifteen of the twenty samples and nine of the ten stations. This is on the OSPAR (2008) list of threatened and/or declining species in the North Sea and also listed as a Feature of Conservation Importance (FOCI) and Priority Marine Feature (PMF) under Marine Conservation Zone (MCZ) guidance (Natural England and Joint Nature Conservation Committee, 2010; Marine Coastal Access Act 2009; Marine Scotland Act 2010). This species was also found in the 2009 and 2012 surveys with 23 juveniles identified, and one adult and fourteen juveniles, respectively. The differences between surveys are attributed to natural spatial and temporal variations. Spawning events for this species should be completed by early October, with settlement occurring for up to several months (Gardline, 2013c). Benthic surveys (Gardline, 2006; Gardline, 2013a) showed the presence of seapens (Virgularia sp. and P. phosphorea) and indicated the seabed was burrowed by infauna. (Figure 3-4 and Figure 3-5 The area therefore has the potential to qualify as the PMF and MPA search feature Burrowed mud and the OSPAR (2008) threatened or declining habitat Seapen and burrowing megafauna communities. Gardline (2013c) indicated that the low density of seapens and the sparse occurrence of visible megafauna was unlikely to qualify the area as OSPAR (2008) habitat, the definition of which includes conspicuous populations of seapens, although it could still qualify as a PMF. The Liberator field does not however fall within any of the extensive current areas of search for Burrowed mud (SNH and JNCC, 2012), and as such is unlikely to be designated as an MPA. The exclusion of the Liberator field from the MPA areas of search suggests that the Liberator field does not support any outstanding examples of this feature. Additional survey work scheduled for 2017 will however provide further information on the possible presence of this feature. Within the Gardline (2006) survey area, bioturbation was evident in the form of occasional circular and elliptical burrows, casts and tracks. Visible fauna included paguridae (hermit crabs), echinoidea (urchins), ophiuroidae (brittlestars), pisces (fish), cnidaria (sea pens) and mollusca (gastropods such as conch). Seabed imagery, acoustic data and seabed samples from the Gardline (2013a) and the Gardline (2006) surveys provided no evidence of the presence of any Annex I habitats within the survey area. The predominant habitat in the area is deemed to correspond to the features Continental shelf muds and Continental shelf sands defined in the Marine Scotland Feature Activity Sensitivity Tool (FEAST). The environmental baseline report associated with the Gardline (2006) survey covering the Blake manifold and Liberator L1 well locations is not available (although the habitat assessment is available as summarised above). It is expected that, given the similarities in the bathymetry, seabed features and habitats identified in the Gardline (2013a) and Gardline (2006) surveys, the benthos will be similar across both survey areas and the results of the 63

64 Gardline (2013) survey data can reasonably be used as a proxy for conditions close to the Blake manifold and L1 well. Similarities in seabed sediments and epifauna at the two survey sites are demonstrated by seabed photography from the Gardline (2013a) survey presented in Figure 3-4 and seabed photography from the Gardline (2006) survey presented in Figure 3-5. Figure 3-4 Photographs of the typical seabed type and fauna from the Project area (station ENV 4) (Gardline, 2013b) Figure 3-5 Further photographs of the typical seabed type and fauna from the Project area (stations ENV 2 and 4) (Gardline, 2006) Fish and shellfish A number of commercially important fish species are present in the vicinity of the Liberator field. Fish and shellfish populations are vulnerable to impacts from offshore installations such as hydrocarbon pollution and exposure to aqueous effluents, especially during the egg and juvenile stages of their lifecycles (Bakke et al., 2013). The North Sea is historically important for its fish stocks with fishing occurring throughout the year. The Liberator field (ICES rectangle 45E8) is located within spawning grounds for plaice Pleuronectes platessa. Certain species use the area for both spawning activities and as a nursery ground including: cod Gadus morhua, herring, lemon sole Microstomus kitt, Norway lobster Nephrops norvegicus, Norway pout Trisopterus esmarkii, sandeel Ammodytes marinus, sprat Sprattus sprattus and whiting Merlangus merlangus. The Liberator field also lies within 64

65 nursery grounds for anglerfish Lophius piscatorius, blue whiting Micromesistius poutassou, European hake Merluccius merluccius, haddock Melanogrammus aeglefinus, ling Molva molva, mackerel Scomber scombrus, spotted ray Raja montagui and spurdog Squalus acanthias (Coull et al., 1998; Ellis et al, 2012). The following species are also listed as Scottish PMFs; Anglerfish, blue whiting, cod, ling, Norway pout, herring, whiting, mackerel and sandeels (SNH, 2014a). Fisheries sensitivity maps produced by Aires et al. (2014) for Marine Scotland Science detail the likelihood of aggregations of fish species in the first year of their life (i.e. group 0 or juvenile fish) occurring around the UKCS. The sensitivity maps indicate that the probability of aggregations of juvenile cod, haddock, whiting, Norway pout, herring, mackerel, horse mackerel Trachurus trachurus, sprat, blue whiting, plaice, sole (all true soles 11 ), European hake and anglerfish in the area of the proposed operations as being low. Spawning grounds are typically regarded as being of higher sensitivity to oil and gas activity than nursery grounds (Cefas, 2001). The operations coincide with peak spawning periods for Norway lobster and sprat along with spawning periods for cod, herring, lemon sole, Norway pout and whiting. Spawning areas for most species are not rigidly fixed and fish may spawn earlier or later from year to year (Coull et al., 1998); therefore mapped areas are indicative at a fairly high level. Many species, whether pelagic or demersal by nature, including sprat, whiting, cod, lemon sole, Norway pout, and plaice spawn into the water column over large areas and so their eggs and juveniles are unlikely to be significantly impacted by the proposed drilling operations in the Liberator field. Herring are indicated as spawning in the Liberator field in the months of August and September. The characteristic that distinguishes this species from others is that it requires a specific benthic habitat on which to lay its eggs, and such habitat is very limited and only occurs in relatively small areas. As described in in Section 3.1.2, the herring spawning ground assessment undertaken at each of the stations revealed that the survey area was not suitable for herring spawning (Gardline, 2013b). However, there are two species in the Liberator field, namely Norway lobster and sandeel, which use the seabed directly for spawning. Norway lobster is widely distributed on muddy substrata throughout the north-east Atlantic (Sabatini and Hill, 2008), and is indicated in Table 3-1 as spawning all year round. Sandeels are indicated as spawning in the Liberator field in the months of November to February. However, Marine Scotland has indicated that February to June is a period of concern for seismic surveys in Blocks 13/23 and 13/24 (OGA, 2016). 11 True soles includes all members of the family Solelidae. 65

66 Table 3-1 Fish spawning and nursery times in Liberator field (ICES rectangle 45E8) (Coull et al., 1998; Ellis et al., 2012) Species Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Anglerfish N N N N N N N N N N N N Blue whiting N N N N N N N N N N N N Cod S/N S/N S/N S/N N N N N N N N N European hake N N N N N N N N N N N N Haddock N N N N N N N N N N N N Herring N N N N N N N S/N S/N N N N Lemon sole N N N S/N S/N S/N S/N S/N S/N N N N Ling N N N N N N N N N N N N Mackerel N N N N N N N N N N N N Norway lobster S/N S/N S/N S/N S/N S/N S/N S/N S/N S/N S/N S/N Norway pout S/N S/N S/N S/N N N N N N N N N Plaice S S S S Sandeel S/N S/N N N N N N N N N S/N S/N Spotted ray N N N N N N N N N N N N Sprat N N N N S/N S/N S/N S/N N N N N Spurdog N N N N N N N N N N N N Whiting N S/N S/N S/N S/N S/N N N N N N N S = Spawning, Peak Spawning, N = Nursery, N = High intensity nursery area, SN = Spawning and nursery, Blank = No data, Seabirds Much of the North Sea and its surrounding coastline and offshore waters are internationally important breeding and feeding habitats for seabirds. Seabirds are not normally adversely affected by routine offshore oil and gas operations on the UKCS; however, in the unlikely event of an oil spill, birds are vulnerable to oiling from surface pollution. This can cause direct toxicity through ingestion, and/or hypothermia as a result of feather damage (JNCC, 1999). In general, seabirds feeding or resting on the sea surface are those most vulnerable to waterborne pollution. The aerial habits of fulmar and gulls, together with their large populations and widespread distribution, reduce their vulnerability to oil related pollution. The offshore distribution and abundance of seabirds varies over the year, being lower during the breeding season when many species return to shore to nest. The offshore distribution outside the breeding season is mostly driven by the availability of food (DECC, 2009). The distance birds will travel from their colonies for food varies greatly between species and this influences 66

67 offshore distribution. Non-breeding birds may be found foraging further offshore than breeding birds. Breeding seabird numbers of some species have shown a long-term decline, most probably as a result of a shortage of key prey species such as sandeels associated with changes in oceanographic conditions (Baxter et al., 2011). The Joint Nature Conservation Committee (JNCC) has released the latest analysed trends in abundance, productivity, demographic parameters and diet of breeding seabirds, from the Seabird Monitoring Programme (JNCC, 2016a). The new data provides at-a-glance UK population trends as a % of change in breeding numbers from complete censuses. From the years , the following population trends for species known to use the Liberator field have been recorded: northern fulmars Fulmarus glacialis (-31%), black legged kittiwakes Rissa tridactyla (-44%) and common guillemots Uria aalge (+5%). Seabird abundance decreases in offshore waters following the winter period (December to February) when large numbers of seabirds start to return to their coastal colonies for the breeding season (April to June). During this breeding period, high numbers of breeding seabirds are linked to their colonies and adjacent coastal waters for feeding. Generally, vulnerability is lowest during the pre-breeding and breeding months, increasing as the breeding season ends and birds disperse into offshore waters. After the breeding season ends in June, large numbers of moulting auks (common guillemot, razorbill Alca torda and Atlantic puffin Fratercula arctica) disperse from their coastal colonies and into the offshore waters from July onwards resulting in peak numbers of seabirds during the summer. In addition to auks, black legged kittiwake, northern gannet Morus bassanus, and northern fulmar, are also present in sizable numbers during the post breeding season. At this time, birds are particularly vulnerable to oil pollution as the adults are rendered flightless due to moulting and the juveniles are not able to fly, therefore they spend a lot of time on the water s surface, significantly increasing their vulnerability to oil pollution on the water surface, i.e. chemical or oil spills. Northern fulmars, black-legged kittiwakes and northern gannet are highly pelagic and capable of travelling long distances to forage. These species are also adaptable, opportunistic feeders, and are sometimes found scavenging around fishing vessels. Oil & Gas UK commissioned a series of seabird surveys to assess the distribution and abundance of both onshore and offshore seabird populations. From these surveys the Seabird Oil Sensitivity Index (SOSI) has been compiled to assess the possible threat of surface pollution to seabirds (JNCC, 2016b). This index is based on the following information: The amount of time spent in the water; The extent to which species are reliant on the marine environment; and The rate at which the population is able to recover with low numbers. The most abundant seabird species found in the Liberator field are northern fulmar, blacklegged kittiwake and common guillemot. Herring gulls Larus argentatus, glaucous gull Larus hyperboreus and great black-backed gulls Larus marinus are known to use the area in winter (DECC, 2009). 67

68 The sensitivity of seabirds to surface oil pollution in the region of the Liberator is presented in Figure 3-6 and Figure 3-7. Table 3-2 presents the SOSI for Blocks 13/23, 13/24 and the surrounding blocks, but blocks containing no data have been populated using the method provided by JNCC (JNCC, 2016b). Given that operations are planned between October and January, these data indicate that the proposed operations at the Liberator well in Block 13/23 are due to take place over a time where sensitivity is low to high, whereas the sensitivity index at the well in Block 13/24 is low to very high during this period. The planned operations at the Liberator field are approximately 64 km from the nearest coastline, and is therefore remote from sensitive seabird breeding areas on the coast. Figure 3-6 Seabird Oil Sensitivity Index at the Liberator wells (January to June) (JNCC, 2016b) 68

69 Figure 3-7 Seabird Oil Sensitivity Index at the Liberator wells (July to December) (JNCC, 2016b) 69

70 Table 3-2 Seabird Oil Sensitivity Index in Blocks 13/23, 13/24 and adjacent blocks Shaded = Blocks populated using the highest index from adjacent months within the same block, according to JNCC s recommendations (JNCC, 2016b) Block Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec 13/ / / / / / / / / / / / Key to sensitivity Marine mammals Cetaceans 1= extremely high, 2 = very high, 3 = high, 4 = medium, 5 = low A total of 19 species of cetacean have been recorded in UK waters (Reid et al., 2003). Sightings of cetacean have been recorded in the vicinity of the Liberator field (Hammond et al., 2004; Reid et al., 2003). Table 3-3 describes the behaviour of the species that are most likely to occur in the project area. Rarer species that are occasionally observed in the North Sea include fin whale Balaenoptera physalus, long-finned pilot whale Globicephala melas, Risso s dolphin Grampus griseus and the short beaked common dolphin Delphinus delphis (NMPI, 2017; Reid et al., 2003). Table 3-3 Occurrence of cetaceans likely to be most regularly observed in the vicinity of the Liberator field (Hammond et al., 2004; Reid et al., 2003) Species Harbour porpoise Phocoena phocoena White-beaked dolphin Description of occurrence Harbour porpoises are frequently seen across the North Sea all year long and are confined to shelf waters. They typically occur in small groups of 2 to 3 individuals but they may aggregate when feeding resources are good. They do not appear to migrate. White-beaked dolphins are frequently seen in the central and northern North Sea, they are present all year round in the UK near-shore waters 70

71 Species Lagenorhynchus albirostris Bottlenose dolphin Tursiops truncatus Minke whale Balaenoptera acutorostrata Atlantic dolphin white-sided Lagenorhynchus acutus Killer whale Orcinus orca Description of occurrence at depths of m, but are observed more frequently between June and October. They are usually found in small groups of 10 or less, but have also been observed in large groups of 50 and more. Bottlenose dolphins are usually seen in groups of 2 to 25, and occasionally much larger groups in deeper waters. They are common near-shore the North-East Scotland, and in the UK the greatest numbers have been observed between July and October, but are present nearshore all year long. Minke whales are distributed in the northern and central North Sea, at water depths of 200 m or less, and are often sighted single or in pairs, and sometimes aggregate into larger groups of up to 15 individuals when feeding. Additionally, they appear to return to the same seasonal feeding grounds. The Atlantic white-sided dolphins are mostly confined to the North Atlantic but have been observed in the North Sea in a number of surveys, particularly in the western part of the North Sea. Their presence is seasonal and peaks between May and September. They are usually observed in groups of tens to hundreds, sometimes up to 1,000 offshore, forming subgroups of 2-15 individuals. Killer whales are widely distributed across the North Sea all year round. They are seen in both inshore waters (April to October) and the deeper continental shelf (November to March) and appear to move inshore to target seals seasonally. The harbour porpoise and the white-beaked dolphin are the most frequently recorded cetaceans in the vicinity of the Liberator field with sightings in eight months of the year which is reflective of those being the most abundant and widely distributed cetaceans in the North Sea (Reid et al., 2003). In the UK there are two known resident populations of bottlenose dolphins, one of which is in the Moray Firth (Thompson et al., 2011). This local population is typically restricted to the inner Moray Firth, and along the north-east coast of Scotland. The inner Moray Firth has been designated as a Special Area of Conservation (SAC) due to the presence of this species. Sightings of bottlenose dolphin in and around the Liberator field have only been recorded in low numbers (JNCC, 2016a) and are rarely seen outside coastal waters though it is thought that they may move offshore during winter (Hammond et al., 2004). The following species are also listed as Scottish PMFs: Atlantic white-sided dolphin, bottlenose dolphin, harbour porpoise, killer whale, white-beaked dolphin, long-finned pilot whale and minke whale (SNH, 2014a). The harbour porpoise is protected under Annex II of the EU Habitats Directive (92/43/EEC as amended by 97/62/EC). Based on the available information, Blocks 13/23 and 13/24 have low cetacean density and is not considered to be significant for feeding, breeding, nursery or migrating cetaceans. The mobile nature of cetaceans means it is unlikely there will be any potentially significant impacts to marine mammals from the proposed drilling activities at the Liberator wells. 71

72 Pinnipeds Five species of pinnipeds have been identified in the North Sea: grey seal Halichoerus grypus, harbour seal Phoca vitulina, harp seal Phoca groenlandica, hooded seal Cystophora cristata and ringed seal Pusa hispida (Jones et al., 2013). However, only two of these species live and breed in the UK, namely the grey and harbour seal, both of which are protected under Annex II of the EU Habitats Directive and are listed as Scottish PMFs (SNH, 2014a). The bearded, ringed, harp and hooded seals are Arctic species, and have generally only been sighted on an occasional basis in Scottish waters. The Sea Mammal Research Unit (SMRU) regularly monitors Scottish seal populations using aerial survey techniques around the Scottish coastline, but these surveys do extend to offshore regions where, in particular, grey seals have been equipped with satellite relay data loggers in order to study their movements and foraging areas (e.g. SCOS, 2014; SMRU, 2011). The JNCC Seabirds at Sea Team (SAST) has also been recording seals during surveys in the Atlantic Margin (Pollock et al., 2000). Approximately 38% of the world s grey seals breed in the UK with 88% of these breeding at colonies in Scotland with the main concentrations in the Outer Hebrides and in Orkney. Birth rates have grown since the 1960s, although population growth is levelling off (SCOS, 2014). In the case of harbour seals, approximately 30% of the world s population are found in the UK. Following significant population declines due to disease in 1988 and 2002, harbour seal numbers on the English east coast have been rising since 2009 (SCOS, 2014). Grey and harbour seals will feed both in inshore and offshore waters depending on the distribution of their prey, which changes both seasonally and annually. Both species tend to be concentrated close to shore, particularly during the pupping and moulting season. Harbour seals haul out every few days on tidally exposed areas of rock, sandbanks or mud. Pupping and moulting seasons occur from May to August, during which time seals will be ashore more often than at other times of the year (Hammond et al., 2004). Seal tracking studies from the Moray Firth have indicated that the foraging movements of harbour seals are relatively local compared to grey seals, and are generally restricted to within a km range of their haulout sites (SCOS, 2014). The movements of grey seals can involve larger distances than those of the harbour seal, and trips of several hundred kilometres from one haul-out to another have been recorded (SMRU, 2011). The Liberator well is approximately 64 km from the nearest landfall so it is unlikely that significant numbers of seals will be found in the vicinity of the proposed operations. This is confirmed by a study carried out by SMRU, which analysed telemetry data of both grey and harbour seals in the UK spanning 1991 to The density maps generated from this work predict (on an annual basis) that seal density in the vicinity of the Liberator field is zero to one harbour seal and one to five grey seals per 25 km 2 (Jones et al., 2013). 72

73 3.4 Conservation Offshore conservation The closest site of conservation interest to the Liberator field is the proposed Southern Trench NCMPA located on the south Moray Firth coast 36 km to the south-west of the Liberator field (Figure 3-8). It has been proposed for MPA designation for the presence of minke whales in high relative density compared to wider Scottish territorial waters, as well as for its frontal zones that create hotspots of pelagic biodiversity, its shelf deeps representing potential nursery areas for certain fish species, and finally for its burrowed muds which is home to the Norway lobster and giant seapens. There is no other site of conservation interest within 40 km of the Liberator field. Both the Braemar Pockmarks SAC (187 km North East from the Liberator field) and the Scanner Pockmarks SAC (138 km east from the Liberator field) are designated due to the presence of submarine structures made by leaking gases (JNCC, 2016c). However, given the distance, it is considered unlikely that this site will be affected by the proposed operations. The surveys undertaken at the Liberator field location revealed silty sand habitats, composed mainly of fine materials, silt and mud (Gardline, 2013b). In total, 61 juvenile ocean quahog A. islandica were identified in the 2013 survey (Gardline, 2013c). A. islandica is on the OSPAR (2008) list of threatened and/or declining species in the North Sea and also listed as a Feature of Conservation Importance (FOCI) and Priority Marine Feature (PMF) under Marine Conservation Zone (MCZ) guidance (Natural England and Joint Nature Conservation Committee, 2010; Marine Coastal Access Act 2009; Marine Scotland Act 2010). Spawning events for this species should be completed by early October, with settlement occurring for up to several months (Gardline, 2013c). Whilst A. islandica is known in the area from previous surveys, the current core distribution of this species in the central North Sea is the Fladen Ground (OSPAR, 2009). As discussed in Section 3.3.1, the area has the potential to qualify as the PMF and MPA search feature Burrowed mud. The Liberator field does not however fall within any of the current areas of search for Burrowed mud (SNH and JNCC, 2012), and as such is unlikely to be designated as an MPA. As discussed in Section 3.2.2, the environmental baseline survey conducted in the vicinity of the Liberator well in 2013 did not provide any evidence of environmentally sensitive habitats or features protected under Annex I of the EU Habitats Directive. It also determined that there is no potential for herring spawning grounds across the survey area as it is too deep, has strong currents and there is no accumulation of coarse material or evidence of well-sorted gravels forming raised banks which is preferred herring spawning habitat (Gardline, 2013b). 73

74 Coastal conservation The closest designated site of conservation interest is the Noss Head NCMPA, located 98 km west of the Liberator field (Figure 3-8). It has been designated to protect horse mussel beds that provides shelter for young fish and crabs, and solid foundation for soft corals, sea firs and tube worms (SNH, 2014b). The East Caithness Cliffs Nature Conservation (NC) MPA and is located at 98.5 km from the Liberator field in the west (Figure 3-8). It is designated to protect black guillemots Cepphus grille (SNH, 2014c). The Moray Firth SAC is located 122 km SW from the Liberator field (Figure 3-8) and is designated for the presence of sandbanks which are slightly covered by sea water at all time under the Annex I Habitats list, and the presence of bottlenose dolphins Tursiops truncatus under the Annex II species list (JNCC, 2016c). However, given the distance and records of sightings of bottlenose dolphin in and around the Liberator field being low (Reid et al., 2003) it is considered unlikely that this site will be affected by the proposed operations. Figure 3-8 Conservation designations in the vicinity of the Liberator field 74

75 Species Grey seals, harbour seals, harbour porpoise and bottlenose dolphin are currently protected under Annex II of the EU Habitats Directive. The inner Moray Firth area has been designated as an SAC due to the presence of bottlenose dolphins; however, bottlenose dolphins are unlikely to be recorded in vicinity of the Liberator wells for most of the year as discussed in Section Bottlenose dolphins are anticipated to move away from areas of disturbance. Harbour and grey seals may be present at the Liberator wells location but their presence is likely to be in low numbers as discussed in Section The only Annex II species regularly recorded in the Liberator well area is the harbour porpoise, however due to their mobile nature they are likely to move away and not be adversely affected by the proposed drilling operations. Bottlenose dolphins are also listed as Scottish PMFs, along with Atlantic white-sided dolphin, bottlenose dolphin, harbour porpoise, killer whale, white-beaked dolphin and minke whale (SNH, 2014a). The occurrence of these species in the Liberator field is detailed in Section Some commercially important fish species occupying the Liberator field are listed as Scottish PMFs: Anglerfish, blue whiting, cod, ling, Norway pout, herring, whiting, mackerel and sandeels (SNH, 2014a). Section describes whether these species occupy the area as spawning or nursery grounds. Non-commercially important fish species of conservation value that are found in UK waters include the European sturgeon Acipenser sturio, which is relatively rare and the common whitefish Coregonus lavaretus both of which qualify for protection under Annex II of the Habitats Directive. Other important species of conservation value include the basking shark Cetorhinus maximus, tope Galeorhinus galeus and porbeagle Lamna nasus. None of these species are recorded in significant densities in the CNS and occur only in small numbers throughout the North Sea during periods of peak zooplankton abundance. Therefore, it is considered unlikely that any of these species will be significantly affected by operations at the Liberator field. Additionally the ocean quahog, A. islandica, listed by OSPAR as an endangered and/or declining species and under the MCZ guidance as a FOCI and PMF, was found across 15 of the 20 samples and 9 of the 10 stations during the 2013 site survey of the Liberator location. Ocean quahog is commonly found within this area of the North Sea (Gardline, 2013c). Aggregations are typically found buried in sediment from the shoreline to depths of approximately 400 m, and can be found on both sides of the North Atlantic and the Baltic region, including within the Liberator region. Ocean quahog is a long-lived bivalve species, with a very slow growth rate, irregular recruitment and high juvenile mortality rates, factors contributing to the overall sensitivities of the population from human activities i.e. seabed disturbance. The inclusion of the ocean quahog on the OSPAR list is attributed to an observed decline in the population, sensitivities and direct threat from seabed disturbance. Management options proposed by OSPAR include limiting seabed disturbance attributed to human activity in the vicinity of ocean quahog aggregations (OSPAR, 2009). 75

76 3.5 Socio-Economic Environment Oil and gas activity Oil and gas development in the outer Moray Firth is sparse compared with other oil and gas areas of the UKCS, although it is not far from extensively developed areas of the CNS. Figure 3-9 illustrates proximity to details the oil and gas activities in the vicinity of the Liberator field. Figure 3-9 Existing infrastructure around the Liberator field 76

77 Offshore wind farms There are four offshore wind farms (OWF) in the outer Moray Firth, namely Telford, MacColl, Stevenson and Beatrice forming the Moray Offshore Renewables Ltd. Area (MORL, 2016) located approximately 68 km to the west of the Liberator field. Commercial fisheries The Liberator field is located in ICES rectangle 45E8 in ICES area IVa; according to the Marine Scotland statistics, the area is primarily targeted for demersal species but shellfish and pelagic species are also landed from this area. Based on statistical data from 2015, landings by vessels into Scotland for ICES rectangle 45E8 (Table 3-4) were dominated by demersal fish which accounted for 82% of the value and 92% of the landed weight. Shellfish accounted for almost 18% of the value and 8% of landed weight, whilst pelagic species accounted for less than 1% of both value and live weight landed (Scottish Government, 2016). Comparing 2015 data with historical data for ICES rectangle 45E8, 2015 data follows a similar trend (NMPI, 2017). In terms of landed weight, haddock was the most landed species comprising 44% of landings, it was also the most valuable species landed accounting for 32% of the landings value for Monks and anglers were also important species in terms of landing value accounting for 28% of the landing value for 2015 (Scottish Government, 2016). Table 3-4 Live weight and value of fish and shellfish from ICES rectangle 45E8 (Scottish Government, 2016) Species type Value ( ) Live weight (tonnes) Value ( ) Live weight (tonnes) Value ( ) Live weight (tonnes) Value ( ) Live weight (tonnes) Value ( ) Live weight (tonnes) Demersal 2,767,639 1,974 2,225,651 1,777 1,092,452 1, , , Pelagic ,059,810 1,630 43, Shellfish 593, , , , ,956, Total 3,360,809 2,153 3,032,769 2,028 1,345,915 1,124 2,707,173 2,392 2,983,855 1,434 In 2015, 830 days were spent fishing in ICES rectangle 45E8 as detailed in Table 3-5. Fishing occurred throughout the year with peaks in effort occurring in September and October. Trawls were the dominant gear type in ICES rectangle 45E8 in 2015 comprising 92% of effort. Seine nets were also used 6% of the time, and dredging accounted for 2% of the effort (Scottish Government, 2016). Fishing intensity in ICES rectangle 45E8 is considered low for pelagic and low to moderate for demersal fisheries in comparison with other areas of the North Sea (Kafas et al., 2012). Furthermore, total effort recorded for ICES rectangle 45E8 is considered relatively low in comparison to the UK total, representing 0.66% of the UK total recorded in 2015 (Scottish Government, 2016). Although commercial fishing in ICES rectangle 45E8 has increased slightly from 2013 to 2014, overall effort in the area is still considered to be low for the majority of the year (Scottish Government, 2016). Comparing 2015 data with historical data for ICES rectangle 45E8, effort in the rectangle 77

78 decreased from however has increased again in recent years (NMPI, 2017). SFF has advised that, historically, the area is most heavily fished in June and early July, with the potential for a substantial number of fishing vessels passing through the development area. This pattern of increased fishing activity in summer months is reflected by the effort data given in Table 3.6, although the latest year for which data are available (2015) saw peak effort in September and October. Table 3-5 Number of days fished per month (all gears) in ICES rectangle 45E8 (Scottish Government, 2016) Year Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec Total D ,069 Note: Monthly fishing effort by UK vessels landing into Scotland: green = days fished, yellow = , orange = , red = 301. Fishing intensity is considered low to moderate for both demersal and pelagic fisheries in comparison with other areas of the North Sea (Kafas et al., 2012). Telecommunication cables There are no telecommunication cables in the vicinity of the Liberator field (KIS-ORCA, 2017). Military activity Block 13/23 and Block 13/24 are not designated as Ministry of Defence (MoD) training grounds (OGA, 2016). Shipping The Liberator field is located in an area defined as having low shipping density (DECC, 2009). The area is mainly used by cargos and oil tankers (DTI, 2001b). Archaeology and other infrastructure Few artefacts of archaeological interest have been recovered from the offshore area within which the Liberator field sits and it is not considered to be an archaeologically rich area. Surveys to date (e.g. Gardline, 2006, Gardline, 2013) have not recorded any wrecks, although SFF have advised that one wreck may sit close to the proposed pipeline route. 12 Table total includes disclosive data thus does not match the numbers in the table. 78

79 4 EIA Methodology 4.1 EIA Overview Offshore activities can involve a number of environmental interactions and impacts due, for example, to operational emissions and discharges and general disturbance. The objective of the EIA process is to incorporate environmental considerations into the Project planning, to ensure that best environmental practice is followed and, ultimately, to achieve a high standard of environmental performance and protection. The process also allows for any potential concerns identified by stakeholders to be addressed appropriately. In addition, it ensures that the planned activities are compliant with legislative requirements and i3 Energy s Environmental policy. 4.2 Environmental Issues Identification (ENVID) The main objective of the ENVID process is to identify the key potential environmental issues requiring discussion and assessment within the EIA, and to agree practicable measures (mitigation) to eliminate or minimise harm to the environment. Development of mitigation measures has considered whether or not seasonal sensitivities are sufficiently great to drive scheduling commitments. The ENVID process was initiated at an early stage within the Project and formed an integral part of the engagement phase with the relevant consultees. The ENVID process was kept under review through the EIA, with mitigation revised as understanding of the Project increased and as consultation continued. The key issues that were assessed in this ES are therefore a combination of issues identified as significant during the early ENVID process (including ENVID workshop, the output of which is detailed in Appendix A), issues of importance raised by consultees (detailed in Section 4.3), and issues that have become clearer with enhanced Project definition. 4.3 Stakeholder Engagement A consultation meeting was held in the early stages of the project; attendees from OPRED, Marine Scotland and JNCC were present. A second consultation meeting was held with the fishing industry (SFF). Overall, the consultees were satisfied with the proposed approach to the EIA, the key environmental issues and potential impacts identified for assessment, and the supporting studies proposed to facilitate assessment. The issues raised through this process have been considered and addressed during the course of the EIA to date, and are summarised in Table

80 Table 4-1 Summary of issues raised during consultation responses, and details of how these have been addressed by the Project OPRED Issues raised Comments on issues raised and ES section in which addressed i3 Energy should discuss the alternatives considered for the Project. This should include a review of the technical feasibility and cost in addition to how the potential environmental impacts of each option was compared. It is recognised that the timing of the 2017 baseline survey work precludes the inclusion of the preliminary findings in the ES. i3 Energy should justify the use of historical surveys in lieu of the 2017 results. Once available, 2017 results should be used to inform future permits. The quoted production figures over the life of the Liberator field (oil, gas, water, and sand, as appropriate) must be the same as those quoted in the final Field Development Plan (FDP). The figures should present the best case (i.e. highest) predicted production levels for any emissions and discharges. A description of how alternatives have been considered by i3 Energy is given in Section 2.1. The latest currently available survey data for the development area has been reviewed by environmental specialists. The latest (2013) survey confirmed to all current best practice guidance for environmental seabed surveys. It was noted that a very short section of the proposed pipeline route from Well L2, close to the Blake manifold, was not covered. This gap will be closed by the 2017 survey work. However, seabed survey data from 2006 (Gardline, 2006) did cover the Blake manifold. Results from that survey indicate that the seabed in the immediate vicinity of the Blake manifold is the same (silty sand) as that found in the 2013 survey area. Given both surveys report the same seabed conditions, and as both reports state the homogeneity of the project area, it is concluded that a robust impact assessment can be undertaken using the latest survey data available. Additionally, i3 Energy and survey environmentalists have together reviewed the initial survey data and consider the initial results to support the habitat definitions given by the previous survey work that serves as the basis for the benthic assessment. As such, Section 3.2 outlines the survey data and Section 5 presents the results of the subsequent impact assessment. The figures presented in Section 2.6 represent the base case (called P10 ) production figures, and reflect those presented in the FDP. 80

81 OPRED (continued) Issues raised Comments on issues raised and ES section in which addressed i3 Energy should provide a likely significant effect assessment arising from the development for major accidents. The impact assessment also needs to incorporate the requirements of the amended EIA Directive, which recognises interplay with the OPEP and OSD in considering which accidents could lead to a likely significant impact. Any modelling presented to support the assessment should describe the worst case fate and release and present relevant mitigation. The ES should state that if mattresses are used, i3 Energy will use the most appropriate mattress, given the length of time and type of environment the mattress is going to be used in. If polypropylene mattresses are to be used BEIS would expect them all to be recovered at the time of decommissioning. The ES should reference human health issues, including emissions to air and water, accidental events and natural disasters The ES should reference predicted effects of climate change. Within each impact assessment (Section ), the likely significant effect on protected sites has been described, as relevant. Within the accidental events assessment in Section 5.7, a description is given of how the relevant scenarios for spill modelling have been selected. This selection process has included consideration of the developing need for ESs to support both OPEP and OSD activities. A description of the mattresses is given in Section 2.4. It is currently assumed that concrete mattresses will be used, which may or may not be bound with polypropylene rope. i3 Energy recognises that such mattresses may require removal at the time of decommissioning and will consider this in the context of the regulatory regime in force at the time of decommissioning. Human health impacts from routine and accidental events were considered during the EIA and were determined to largely require no further assessment within the EIA process, especially since activities will be managed to meet industry requirements for safe operations. Section 5.6 describes possible local air quality issues associated with the Project. Accidental events have been assessed fully in Section 5.7. It is considered that the implication of any natural disasters affecting the offshore region, such as an earthquake or extreme sea conditions, would most likely be the accidental events described in Section 5.7 and are not thus considered separately. Mitigation relevant to minimise the risk of accidental events occurring from operational failure is likely to be appropriate in limiting the likelihood of such natural disasters. Section 5.6 describes possible issues related to climate change. 81

82 OPRED (continued) Issues raised Comments on issues raised and ES section in which addressed The ES should include a table outlining environmental commitments and details of how these will be monitored/audited to ensure compliance. Information regarding how plans for decommissioning the Liberator field have been incorporated into the design process should be presented. The impact assessment should include a cumulative impact assessment at both the project level and in relation to neighbouring development. Marine Scotland When assessing the impact of drill cuttings discharge, any comparison to the literature should include information on the relative volumes and types of cuttings discharges, and of similarities or otherwise in environmental conditions such as geographical location, water depth, tidal exposure. The ES should include information on the type of protection around the infrastructure, whether they will be fishing friendly (where snagging could still occur) or overtrawlable (safe for trawling). The ES should note whether the integrity of existing Blake pipelines is also suited to an extended field life or whether these are likely to require replacement. Commitments to mitigate impact and/or control issues are given throughout the ES. Appendix C includes a summary table of those commitments. Section 6 outlines i3 Energy s Integrated Management System (IMS) and provides details of how commitments will be implemented. The extent to which decommissioning has been dealt with in design is explained in Section 2.8. Each impact assessment (Section ) has a dedicated section that assesses the potential impact from cumulative sources. The impact assessment in Section 5 details the expected likely impact of drill cuttings. The assessment is supported by both a robust literature review and expert judgement to understand how the limited discharges from the two single wells could impact upon the seabed. Discharge of cuttings with respect to water column impacts is considered in Section 5.2. The trees used will be SFF approved, fishing friendly and incorporate protection structures able to resist loads in excess of the bollard pull generated by fishing vessels active in the area. In conjunction with the owners of the Blake infrastructure, i3 Energy can advise that the integrity of the existing infrastructure is sufficient to mean that no replacement of any existing infrastructure is required as a result of the Liberator Phase 1 Field Development. 82

83 Issues raised Marine Scotland (continued) Comments on issues raised and ES section in which addressed Use should be made of the NMPi online data resource, and specifically of the most recently added map layers relating to various aspects of fisheries and fishing effort. The ES should use the Feature Activity Sensitivity Tool (FEAST) to be used to assist in describing the likely impacts on species of conservation concern or species indicative of conservation habitats. JNCC JNCC noted the availability of the latest online data including Ocean Biogeographic Information System Spatial Ecological Analysis of Megavertebrate Populations (OBIS SEAMAP), and offered assistance and advice regarding recent data sources. Use should be made of the latest seabird sensitivity to oil pollution data. SFF The area is most heavily fished June to early July with the potential for a lot of fishing vessel movement SFF advised that the wellhead protection structure is expected to be fishing friendly rather than over-trawlable, due to the likely size. SFF advised that the underlying seabed material could be clay and, if disturbed by V trenching, could create a high clay berm that is problematic to fishing The environment description in Sections 3.2, 3.3 and outlines how NMPI has been used to inform not only the fisheries assessment but also physical and biological descriptions. The assessment of protected sites that is included within each relevant impact assessment in Section has made use of FEAST, as appropriate. The review of environmental sensitivities undertaken for the ES has included consideration of a large number of data sources, including OBIS SEAMAP. It was decided that there was more relevant, receptor specific data available, and as such the most relevant available data sources are presented in the environmental baseline and impact assessment. Specifically for seabirds, the environment description (Section 3.3.3) presents the latest sensitivity data (JNCC, 2016c) and the assessment of accidental events (Section 5.7) has given consideration to the predicted sensitivity. This information has been incorporated into the baseline description of fishing activity given in Section i3 Energy recognises this input to design and has considered the likely impacts on fisheries users from deploying such a fishing friendly design. i3 Energy expect to deploy a water jet to trench the pipeline and umbilical, such that there will be no development of clay berms. The potential impact of the proposed activities on fishing is assessed in Section

84 SFF (continued) Issues raised Comments on issues raised and ES section in which addressed SFF noted that there is a wreck possibly positioned on the proposed pipeline route. All i3 Energy propose to scope out impacts resulting from produced water discharge, emissions to atmosphere from operational fuel use and flaring on the FPSO, and operational waste generation by FPSO, if reported volumes and characteristics are no different or less that existing figures. i3 Energy propose to carry out a qualitative assessment of underwater noise impacts rather than undertaking propagation modelling, since experience with Vertical Seismic Profiling surveys have shown that the only likely impacts are disturbance or avoidance. This is due to the fact that the zone of potential physical injury is extremely small in these models, and also much smaller than the zone monitored by marine mammal observers implementing the JNCC mitigation measures. i3 Energy propose to carry out oil spill modelling for worst-case oil spill incident (well blowout) plus loss of marine diesel fuel inventory (rig or FPSO), and proposal to not model loss of containment from the ~2 km pipeline from Well L2 to Blake. If bringing Liberator on stream extends the life of the FPSO this should be made clear in the ES and impacts should be assessed. This information has been incorporated into the baseline description of archaeological features given in Section This approach was agreed by consultees. However, it was determined during the EIA that produced water discharge from the Bleo Holm FPSO was likely to increase over the life of the Project (not just as a result of Liberator fluids) and this potential impact is assessed in Section 5. Operational waste generation is anticipated to be entirely within existing handling capacity and no further consideration is given to this. The qualitative assessment method was agreed by consultees. A full impact assessment of VSP is given in Section 5.4, with appropriate mitigation built into the assessment of residual impact. The modelling approach was agreed by consultees. A full impact assessment is given in Section 5.7. Following review of the modelling for the well blowout scenario it was decided that this scenario was by far the worst case, and additional modelling for a diesel release would not add further value to the assessment. Diesel release has therefore been assessed qualitatively in Section Future permit applications will be supported by additional modelling if required. There is no change to the expected life of the FPSO and this issue is not considered further in the EIA. 84

85 All (continued) Issues raised Comments on issues raised and ES section in which addressed The environment baseline should include information on other sea users, specifically cultural heritage information (including wrecks), together with military practice and exercise areas and shipping/other vessels. 4.4 Environmental Significance Overview This baseline information is presented in Section 3 and any relevant potential environmental impact described in Section The decision process related to defining whether or not a project is likely to significantly impact on the environment is the core principle of the EIA process; the methods used for identifying and assessing potential impacts should be transparent and verifiable. The method presented here has been developed by reference to the Institute of Ecology and Environmental Management (IEEM) guidelines for marine impact assessment (IEEM, 2010), the Marine Life Information Network (MarLIN) species and ecosystem sensitivities guidelines (Tyler-Walters et al., 2001), guidance provided by Scottish Natural Heritage (SNH) in their handbook on EIA (SNH, 2013) and by The Institute of Environmental Management and Assessment (IEMA) in their guidelines for EIA (IEMA, 2016). The EIA provides an assessment of the environmental effects that may result from a project s impact on the receiving environment. The terms impact and effect have different definitions in EIA and one drives the other. Impacts are defined as the changes resulting from an action, and effects are defined as the consequences of those impacts. In general, impacts are specific, measureable changes in the receiving environment (volume, time and/or area); for example, were a number of marine mammals to be disturbed following exposure to vessel noise emissions. Effects (the consequences of those impacts) consider the response of a receptor to an impact; for example, the effect of the marine mammal/noise impact example given above might be exclusion from an area caused by disturbance, leading to a population decline. The relationship between impacts and effects is not always so straightforward; for example, a secondary effect may result in both a direct and indirect impact on a single receptor. There may also be circumstances where a receptor is not sensitive to a particular impact and thus there will be no significant effects/consequences. For each impact, the assessment identifies a receptor s sensitivity and vulnerability to that effect and implements a systematic approach to understand the level of impact. The process considers the following: Identification of receptor and impact (including duration, timing and nature of impact); Definition of sensitivity, vulnerability and value of receptor; Definition of magnitude and likelihood of impact; and 85

86 Assessment of consequence of the impact on the receptor, considering the probability that it will occur, the spatial and temporal extent and the importance of the impact. If the assessment of consequence of impact is determined as moderate or major, it is considered a significant impact. Once the consequence of a potential impact has been assessed it is possible to identify measures that can be taken to mitigate impacts through engineering decisions or execution of the project. This process also identifies aspects of the project that may require monitoring, such as a postdecommissioning survey at the completion of the works to inform inspection reports. For some impacts significance criteria are standard or numerically based. For others, for which no applicable limits, standards or guideline values exist, a more qualitative approach is required. This involves assessing significance using professional judgement. Despite the assessment of impact significance being a subjective process, a defined methodology has been used to make the assessment as objective as possible and consistent across different topics. The assessment process is summarised below. The terms and criteria associated with the impact assessment process are described and defined; details on how these are combined to assess consequence and impact significance are then provided. Baseline characterisation and receptor identification In order to make an assessment of potential impacts on the environment it was necessary to firstly characterise the different aspects of the environment that could potentially be affected (the baseline environment). The baseline environment has been described in Section 3 and is based on desk studies combined with additional site-specific surveys where required. Information obtained through consultation with key stakeholders was also used to help characterise specific aspects of the environment in more detail. Where data gaps and uncertainties remained (e.g. where there are no suitable options for filling data gaps), as part of the EIA process these have been documented and taken into consideration as appropriate as part of the assessment of impact significance (Section 4.3.5). The EIA process requires identification of the potential receptors that could be affected by the Project (e.g. marine mammals, seabed species and habitats). High level receptors are identified within the impact assessments (Section 6). Impact definition Impact magnitude Determination of impact magnitude requires consideration of a range of key impact criteria including: Nature of impact, whether it be beneficial or adverse; Type of impact, be it direct or indirect etc.; Size and scale of impact, i.e. the geographical area; Duration over which the impact is likely to occur i.e. days, weeks; 86

87 Seasonality of impact, i.e. is the impact expected to occur all year or during specific times of the year e.g. summer; and Frequency of impact, i.e. how often the impact is expected to occur. Each of these variables are expanded upon in Table 4-2 to Table 4-5 to provide consistent definitions across all EIA topics. In each impact assessment, these terms are used in the assessment summary table to summarise the impact, and are enlarged upon as necessary in any supporting text. With respect to the nature of the impact (Table 4-2), it should be noted that all impacts discussed in this ES are adverse unless explicitly stated. Table 4-2 Nature of impact Nature of impact Beneficial Adverse Definition Advantageous or positive effect to a receptor (i.e. an improvement). Detrimental or negative effect to a receptor. Table 4-3 Type of impact Type of impact Direct Indirect Cumulative Definition Impacts that result from a direct interaction between the Project and the receptor. Impacts that are actually caused by the introduction of Project activities into the receiving environment. E.g. The direct loss of benthic habitat. Reasonably foreseeable impacts that are caused by the interactions of the Project but which occur later in time than the original, or at a further distance from the proposed Project location. Indirect impacts include impacts that may be referred to as secondary, related or induced. E.g. The direct loss of benthic habitat could have an indirect or secondary impact on by-catch of non-target species due to displacement of these species caused by loss of habitat. Impacts that act together with other impacts (including those from any concurrent or planned future third party activities) to affect the same receptors as the proposed Project. Definition encompasses in-combination impacts. Table 4-4 Duration of impact Duration Short term Temporary Definition Impacts that are predicted to last for a short duration (e.g. less than one year). Impacts that are predicted to last a limited period (e.g. a few years). For example, impacts that occur during the decommissioning activities and which do not extend beyond the main activity period for the works or which, due to the timescale for 87

88 Duration Prolonged Permanent Definition mitigation, reinstatement or natural recovery, continue for only a limited time beyond completion of the anticipated activity Impacts that may, although not necessarily, commence during the main phase of the decommissioning activity and which continue through the monitoring and maintenance, but which will eventually cease. Impacts that are predicted to cause a permanent, irreversible change. Table 4-5 Frequency of impact Frequency Continuous Intermittent Description Impacts that occur continuously or frequently. Impacts that are occasional or occur only under a specific set of circumstances that occurs several times during the course of the Project. This definition also covers such impacts that occur on a planned or unplanned basis and those that may be described as periodic impacts. Table 4-6 Geographical extent of impact Geographical extent Local Regional National Description Impacts that are limited to the area surrounding the proposed Project footprint and associated working areas. Alternatively, where appropriate, impacts that are restricted to a single habitat or biotope or community. Impacts that are experienced beyond the local area to the wider region, as determined by habitat/ecosystem extent. Impacts that affect nationally important receptors or protected areas, or which have consequences at a national level. This extent may refer to either Scotland or the UK depending on the context. Transboundary Impacts that could be experienced by neighbouring national administrative areas. International Impacts that affect areas protected by international conventions, European and internationally designated areas or internationally important populations of key receptors (e.g. birds, marine mammals) Impact Magnitude Criteria Overall impact magnitude requires consideration of all impact parameters described above. Based on these parameters, magnitude can be assigned following the criteria outlined in Table 88

89 4-7. The resulting effect on the receptor is considered under vulnerability and is an evaluation based on scientific judgement. Table 4-7 Impact magnitude criteria Magnitude Major Moderate Minor Negligible Positive Criteria Extent of change: Impact occurs over a large scale or spatial geographical extent and /or is long term or permanent in nature. Frequency/intensity of impact: high frequency (occurring repeatedly or continuously for a long period of time) and/or at high intensity. Extent of change: Impact occurs over a local to medium scale/spatial extent and/or has a prolonged duration. Frequency intensity of impact: medium to high frequency (occurring repeatedly or continuously for a moderate length of time) and/or at moderate intensity or occurring occasionally/intermittently for short periods of time but at a moderate to high intensity. Extent of change: Impact occurs on-site or is localised in scale/spatial extent and is of a temporary or short term duration. Frequency/intensity of impact: low frequency (occurring occasionally/intermittently for short periods of time) and/or at low intensity. Extent of change: Impact is highly localised and very short term in nature (e.g. days/ few weeks only). An enhancement of some ecosystem or population parameter. Notes: Magnitude of an impact is based on a variety of parameters. Definitions provided above are for guidance only and may not be appropriate for all impacts. For example an impact may occur in a very localised area (minor to moderate) but at very high frequency/intensity for a long period of time (major). In such cases informed judgement is used to determine the most appropriate magnitude ranking and this is explained through the narrative of the assessment Impact likelihood for unplanned and accidental events The likelihood of an impact occurring for unplanned/accidental events is another factor that is considered in this impact assessment (Table 4-8). This captures the probability that the impact will occur and also the probability that the receptor will be present and is generally based on knowledge of the receptor and experienced professional judgement. Consideration of likelihood is described in the impact characterisation text and used to provide context to the specific impact being assessed in topic specific chapters as required. 89

90 Table 4-8 Probability of accidental events occurring Likelihood category Likely More than once per year Accidental event probability Event likely to occur more than once on the facility Possible One in 10 years Could occur within the life time of the Project Unlikely One in 100 years Event could occur within life time of 10 similar facilities. Has occurred at similar facilities. Remote One in 1,000 years Similar event has occurred somewhere in industry or similar industry but not likely to occur with current practices and procedures. Extremely remote One in 10,000 years Has never occurred within industry or similar industry but theoretically possible Overview Receptor definition As part of the assessment of impact significance it is necessary to differentiate between receptor sensitivity, vulnerability and value. The sensitivity of a receptor is defined as the degree to which a receptor is affected by an impact and is a generic assessment based on factual information whereas an assessment of vulnerability, which is defined as the degree to which a receptor can or cannot cope with an adverse impact is based on professional judgement taking into account an number of factors, including the previously assigned receptor sensitivity and impact magnitude, as well as other factors such as known population status or condition, distribution and abundance Receptor sensitivity Example definitions for assessing the sensitivity of a receptor are provided in Table

91 Table 4-9 Sensitivity of receptor Receptor sensitivity Very high High Medium Low Negligible Definition Receptor with no capacity to accommodate a particular effect and no ability to recover or adapt. Receptor with very low capacity to accommodate a particular effect with low ability to recover or adapt. Receptor with low capacity to accommodate a particular effect with low ability to recover or adapt. Receptor has some tolerance to accommodate a particular effect or will be able to recover or adapt. Receptor is generally tolerant and can accommodate a particular effect without the need to recover or adapt Receptor vulnerability Information on both receptor sensitivity and impact magnitude is required to be able to determine receptor vulnerability as per Table Table 4-10 Vulnerability of receptor Receptor vulnerability Very high High Medium Low Negligible Definition The impact will have a permanent effect on the behaviour or condition on a receptor such that the character, composition or attributes of the baseline, receptor population or functioning of a system will be permanently changed. The impact will have a prolonged or extensive temporary effect on the behaviour or condition on a receptor resulting in long term or prolonged alteration in the character, composition or attributes of the baseline, receptor population or functioning of a system. The impact will have a short term effect on the behaviour or condition on a receptor such that the character, composition, or attributes of the baseline, receptor population or functioning of a system will either be partially changed post development or experience extensive temporary change. Impact is not likely to affect long term function of system or status of population. There will be no noticeable long term effects above the level of natural variation experience in the area. Changes to baseline conditions, receptor population of functioning of a system will be imperceptible. It is important to note that the above approach to assessing sensitivity/vulnerability is not appropriate in all circumstances and in some instances professional judgement has been used 91

92 in determining sensitivity. In some instances it has also been necessary to take a precautionary approach where stakeholder concern exists with regard to a particular receptor. Where this is the case, this is detailed in the relevant impact assessment in Section Receptor value The value or importance of a receptor is based on a pre-defined judgement based on legislative requirements, guidance or policy. Where these may be absent, it is necessary to make an informed judgement on receptor value based on perceived views of key stakeholders and specialists. Examples of receptor value definitions are provided in Table Table 4-11 Receptor value Value of receptor Very high High Medium Definition Receptor of international importance (e.g. United Nations Educational, Scientific and Cultural Organisation (UNESCO) World Heritage Site (WHS)). Receptor of very high importance or rarity, such as those designated under international legislation (e.g. EU Habitats Directive) or those that are internationally recognised as globally threatened (e.g. IUCN red list). Receptor has little flexibility or capability to utilise alternative area. Best known or only example and/or significant potential to contribute to knowledge and understanding and/or outreach. Receptor of national importance (e.g. NCMPA, MCZ). Receptor of high importance or rarity, such as those which are designated under national legislation, and/or ecological receptors such as United Kingdom Biodiversity Action Plan (UKBAP) priority species with nationally important populations in the study area, and species that are near-threatened or vulnerable on the IUCN red list. Receptor provides the majority of income from the Project area. Above average example and/or high potential to contribute to knowledge and understanding and/or outreach. Receptor of regional importance. Receptor of moderate value or regional importance, and/or ecological receptors listed as of least concern on the IUCN red list but which form qualifying interests on internationally designated sites, or which are present in internationally important numbers. Any receptor which is active in the Project area and utilises it for up to half of its annual income/activities. Average example and/or moderate potential to contribute to knowledge and understanding and/or outreach. 92

93 Value of receptor Low Negligible Receptor of local importance. Definition Receptor of low local importance and/or ecological receptors such as species which contribute to a national site, are present in regionally. Any receptor which is active in the Project area and reliant upon it for some income/activities. Below average example and/or low potential to contribute to knowledge and understanding and/or outreach. Receptor of very low importance, no specific value or concern. Receptor of very low importance, such as those which are generally abundant around the UK with no specific value or conservation concern. Receptor of very low importance and activity generally abundant in other areas/ not typically present in the Project area. Poor example and/or little or no potential to contribute to knowledge and understanding and/or outreach Overview Consequence and significance of potential impact Having determined impact magnitude and the sensitivity, vulnerability and value of the receptor, it is then necessary to evaluate impact significance. This involves: Determination of impact consequence based on a consideration of sensitivity, vulnerability and value of the receptor and impact magnitude; Assessment of impact significance based on assessment consequence; Mitigation; and Residual impacts Assessment of consequence and impact significance The sensitivity, vulnerability and value of receptor are combined with magnitude (and likelihood, where appropriate) of impact using informed judgement to arrive at a consequence for each impact, as shown in Table The significance of impact is derived directly from the assigned consequence ranking. Table 4-12 Assessment of consequence Assessment consequence Major Description (consideration of receptor sensitivity and value and impact magnitude) Impacts are likely to be highly noticeable and have long term effects, or permanently alter the character of the baseline and are likely to disrupt the function and status/value of the receptor population. They may have broader systemic consequences (e.g. Impact significance Significant 93

94 Assessment consequence Moderate Low Negligible Positive Description (consideration of receptor sensitivity and value and impact magnitude) to the wider ecosystem or industry). These impacts are a priority for mitigation in order to avoid or reduce the anticipated effects of the impact. Impacts are likely to be noticeable and result in prolonged changes to the character of the baseline and may cause hardship to, or degradation of, the receptor population, although the overall function and value of the baseline/ receptor population is not disrupted. Such impacts are a priority for mitigation in order to avoid or reduce the anticipated effects of the impact. Impacts are expected to comprise noticeable changes to baseline conditions, beyond natural variation, but are not expected to cause long term degradation, hardship, or impair the function and value of the receptor. However, such impacts may be of interest to stakeholders and/or represent a contentious issue during the decision-making process, and should therefore be avoided or mitigated as far as reasonably practicable Impacts are expected to be either indistinguishable from the baseline or within the natural level of variation. These impacts do not require mitigation and are not anticipated to be a stakeholder concern and/or a potentially contentious issue in the decisionmaking process. Impacts are expected to have a positive benefit or enhancement. These impacts do not require mitigation and are not anticipated to be a stakeholder concern and/or a potentially contentious issue in the decision-making process. Impact significance Significant Not significant Not significant Not significant Mitigation Where potentially significant impacts (i.e. those ranked as being of moderate impact level or higher in Table 4-12) are identified, mitigation measures must be considered. The intention is that such measures should remove, reduce or manage the impacts to a point where the resulting residual significance is at an acceptable or insignificant level. For impacts that are deemed not significant (i.e. low, negligible or positive in Table 4-12), there is no requirement to adopt specific mitigation. However, mitigation can be adopted in such cases to ensure impacts that are predicted to be not significant remain so. Section 8 provides detail on how any mitigation measures identified during the impact assessment will be managed. Residual impacts Residual impacts are those that remain once all options for removing, reducing or managing potentially significant impacts (i.e. all mitigation) have been taken into account. 94

95 4.5 Cumulative and In-Combination Impact Assessment The European Commission has defined cumulative impact as being those resulting from incremental changes caused by other past, present or reasonably foreseeable actions together with the project (European Commission, 1999). As outlined in studies by the European Commission (1999) and US CEQ (1997), identifying the cumulative impacts of a project involves: Considering the activities associated with the project; Identifying potentially sensitive receptors/resources; Identifying the geographic and time boundaries of the cumulative impact assessment; Identifying past, present and future actions which may also impact the sensitive receptors/resources; Identifying impacts arising from the proposed activities; and Identifying which impacts on these resources are important from a cumulative impacts perspective. To assist the assessment of cumulative and in-combination impacts, a review of existing developments (including oil and gas, cables and renewables) that could have the potential to interact with the Project was undertaken; the output of this review is reported in the Environment Description (Section 3). The impact assessment has considered these projects when defining the potential for cumulative and in-combination impact (Section 5). This includes, where appropriate, reference to existing fields producing through the Bleo Holm FPSO. 4.6 Transboundary Impact Assessment The impact assessment presented in Section 6 contains sections which identify the potential for, and where appropriate, assessment of transboundary impacts. For the Liberator Phase 1 Field Development, this is less of an issue than for some North Sea developments, considering that it lies 170 km from the UK/Norway median line. 4.7 Habitats Regulation Appraisal (HRA) Under Article 6.3 of the Habitats Directive, it is the responsibility of the Competent Authority to make an Appropriate Assessment of the implications of a plan, programme or in this case project, alone or in combination, on a Natura site (SAC or SPA) in view of the site s conservation objectives and the overall integrity of the site. As part of the assessment of impacts on key receptors, for those receptors that are a qualifying feature of a Natura site, relevant information on SACs or SPAs has also been provided as part of the impact assessment process. This information will then be used by the Competent Authority to determine the need for, and subsequently carry out (if required), an appropriate assessment of the Project. For offshore areas ( nm) the requirements of the Habitats Directive are transposed through the Offshore Marine Conservation Natural Habitats Regulations (2007) as amended. 95

96 In accordance with these Regulations, the impacts of a project on the integrity of a European site are assessed and evaluated as part of the HRA process. In an analogous process, the Marine (Scotland) Act and the Marine and Coastal Access Act require the potential for significant risk to the conservation objectives of NCMPAs and MCZs (respectively) being achieved to be assessed. 4.8 Data Gaps and Uncertainties Baseline data The North Sea has been extensively studied, meaning that this EIA has been able to draw on a significant volume of published data. This bank of published data has been supplemented by a site survey studies that have previously been undertaken within the Project area. Additionally, i3 Energy has commissioned specific site-survey work to confirm the existing understanding of the environmental baseline. This survey campaign, which covered environmental baseline and habitat assessment, has now been completed for the Project area. However, the data collected are currently being analysed and the information collected has not been available to inform this EIA. This is recognised as a current gap in the EIA but, as outlined in Section 4.3, it is not considered to compromise the robustness of the EIA itself. i3 Energy will make use of the information that has been collected in any permits applications that are prepared following the survey results being reported. Project data It should be recognised that, until further engineering study work has been completed, it is not possible to definitively state the final design for the structures, pipelines and umbilicals to be installed subsea. To account for this uncertainty, worst case assumptions have been made, and where key uncertainties exist they have been outlined within the relevant section of the impact assessment (Section 6). Similarly, until further detailed work has been undertaken on how the Bleo Holm FPSO will handle the fluids from the Liberator field, assumptions regarding fuel use, flaring and produced water handling have to have been made. These assumptions are clearly outlined in the relevant sections of this ES (primarily Sections 2 and 5). Potential for Impact When evaluating and characterising potential impacts that could be associated with the Project, a variety of inputs are used, including baseline environmental data, modelling results, estimation of emissions and Project footprint. These inputs carry varying levels of uncertainty and conservatism and although potential impacts may occur, they are not certain to occur (for example, there is some uncertainty in marine mammal response to certain noise emissions). As such, all the potential impacts (whether predicted, residual, cumulative and in-combination or transboundary) described in this ES are to a greater or lesser extent potential impacts which may or may not occur. 96

97 5 Impact Assessment 5.1 Introduction The key issues identified for assessment during the EIA process are detailed in Table 5-1. The impact assessment for each of these topics is presented in the following sections. It is important to note that many of the potential operational impacts associated with the Liberator Phase 1 Field Development will be managed through the existing permits that the Bleo Holm FPSO currently holds. Table 5-1 Potential impacts to be assessed during the EIA process Potential impact Discharges to sea Physical presence: Seabed disturbance Underwater noise Other sea users Atmospheric emissions Accidental events Description Discharge of drilling muds, cuttings, cementing and completion chemicals from drilling operations, routine chemical use and discharge to sea during pipeline installation and commissioning and discharge of produced water during operation, resulting in changes in water quality, localised and temporarily increased suspended solid concentrations, and possible impacts to organisms in the water column. Direct loss of benthic species and seabed habitat, wider indirect disturbance to the benthic environment through the suspension and re-settlement of sediments and introduction of new habitat resulting from drill cuttings settling on the seabed, installation of structures, use of anchors and placement of rock and mattresses. Possible disturbance of drill cuttings that may already be present close to the Blake manifold. Possible disturbance to marine mammals and fish through noise from vessel use. For the small-scale nature of the proposed drilling and installation activities, the noise emissions are of little concern for cetaceans and they are not considered further in this assessment as a standalone emission. However, they have been considered as part of the assessment of cumulative noise emissions. Potential temporary interference with shipping and fishing activities during installation, loss of access to seabed for fisheries on a temporary or permanent basis, increased risk of vessel collisions through the presence of vessels during installation activities Contribution to global greenhouse gases through emission of carbon dioxide (CO 2 ) and generation of acid rain from oxides of nitrogen (NOx) and sulphur (SOx) resulting from fuel use during installation and from flaring during drilling, from vessel use during installation and operation, and from fuel use and flaring at the Bleo Holm FPSO. Potential for toxicity and smothering impacts to marine and coastal species and habitats through the release of hydrocarbons and chemicals from a well blowout or pipeline inventory loss and accidental release of fuel or chemicals from the drill rig. 97

98 5.2 Discharges to Sea Overview Description and quantification of impact Discharges to sea during the drilling phase of the Project will include mud, cuttings, cement and wellbore completion and well test chemicals. Discharges due to installation of subsea infrastructure will include chemicals used in pipeline flooding and cleaning, and installation and commissioning of spools, manifolds and umbilicals. There will be no discharge other than of nitrogen gas during commissioning of the gas lift line. Discharges during production from the Liberator field will be handled within the existing capacity of the Bleo Holm FPSO, with an incremental increase in overall oil discharge expected as a result of the increase in the volume of produced water being handled. The above discharges may lead to potential impacts on the seabed or water column through the following mechanisms: Increased suspended solids in the water column; Settlement of cuttings and muds on the seabed; and Potential toxic impacts from hydrocarbons and chemical additives discharged. The potential for smothering, habitat change, sediment loading near the seabed and interference with seabed fauna caused by drilling discharges is discussed in Section 5 and not discussed further here. This section focuses on the potential for water column impacts from the discharge of material from the wellbores and pipeline installation and commissioning activities, as well as from the incremental oil discharge during production from the Liberator field Drilling mud, cuttings and cement discharges As discussed in Section 2.2, the two proposed wells will be drilled mainly using WBM. There is a possibility that LTOBM will be used for the 12¼ꞌꞌ section, but in this instance returned cuttings would be skipped and shipped to shore and there would be no discharge of LTOBM or contaminated cuttings to sea. Likewise, WBM cuttings contaminated with reservoir hydrocarbons will be retained and shipped to shore for treatment and disposal. Assuming as a worst case that all sections are drilled with WBM, a combined total of approximately 3,025 tonnes of WBM and cuttings, and 108 tonnes of cement may be discharged from each well. Of these totals, 1,375 tonnes of WBM and cuttings and 108 tonnes of cement would be discharged at the seabed during riserless drilling and cementing operations, with a further 1,650 tonnes of WBM and cuttings (but no cement) discharged from the drill rig topsides once the marine riser is in place Chemical discharges Chemicals will be required to clean up and complete the well once drilling is complete. These chemicals will be returned to the drilling rig, and are likely to be contaminated with reservoir fluids and drilling mud. Material returned from the well during wellbore cleanup and completion will be processed on the drilling rig to ensure that only liquids that contain less than 30 mg/l oil in water are being discharged overboard. 98

99 Pipeline, jumper and spool installation and commissioning will require chemicals to inhibit and dye seawater used for pressure testing. Once pressure and leak testing is complete the lines will be flushed with glycol or diesel in preparation for production startup, at this point seawater and chemicals from the lines will be discharged to sea. Routine chemical use and discharge during field operation will involve small amounts of hydraulic fluid for valve operation. These discharges are expected to be on an extremely small scale and are not expected to have a significant impact, therefore they are not discussed further here. Use and discharge of operational chemicals will be managed by i3 Energy to meet the conditions within the chemical permit and the requirements of the Offshore Chemical Regulations Produced water discharge Operational discharges of produced water will occur as part of the current Bleo Holm process. There will be no requirement to modify any chemical use in the produced water system as part of the Liberator field production coming online. In addition to continuation of the currently permitted chemical use and discharge in the Bleo Holm produced water system, it is expected that the produced water system at Bleo Holm will discharge small volumes of oil up to a maximum average of 30 mg/l. The production profiles for the Liberator Phase 1 Field Development that are shown in Section 2.6 show what is called the P10, which presents what is considered to be at the upper estimates of the most probable production values. However, it is important to consider the production estimates associated with the lower oil and gas estimates, since they often show a higher water production (since in those circumstances the reservoir has less oil and gas in it, and more water). Estimated discharge of produced water associated with both the low and high oil and gas production cases is shown in Table 5.2. In both cases, the oil tonnage that could be discharged to sea via the produced water system over the expected seven year life of the Liberator Phase 1 Field Development is likely to be very small. 99

100 Table 5-2 Estimated Liberator Phase 1 Field Development oil quantity discharged via produced water stream over the seven year life of field (based on P10 figures) assuming 30 mg/l oil in water Overboard discharge of produced water (m 3/ day) Estimated oil discharge (tonnes/year) assuming 30 mg/l oil in water concentration High Oil and Gas Low Oil and Gas Production Case Production Case Year High Oil and Gas Low Oil and Gas Production Case Production Case Potential impacts Drilling discharges directly to the seabed are expected to result in limited water column sediment loading within a few metres of the top of the well bore. Discharges from the rig topsides are likely to form a plume in the water column as discharged material disperses out with the prevailing current, which is likely to change direction with the tide several times over the discharge period. This is likely to result in a moderately large volume of water experiencing an increased sediment load. Increased water sediment load may cause interference with feeding, respiration and orientation of marine fauna. It may also cause physical irritation by abrading protective mucous coatings and increase susceptibility to parasites and infections. Mobile fauna are likely to exhibit avoidance behaviour and avoid the sediment plume. Plankton, which cannot effectively control its geographical location (although many species undertake vertical migration) may be impacted by increased sediment loads, which may cause behavioural change (lack of feeding) or even mortality in some individuals. This impact however is not considered significant as the impact will be short-lived and on a small scale when set against the large plankton population and available habitat in the wider area, and naturally high mortality rates. The potential for toxic impacts on water column receptors from drilling, installation and operational discharge depends on many factors including the sensitivity of the receptor organism (which can vary widely between species), the toxicity of the chemicals used, the concentration of the chemicals and hydrocarbons in the discharge stream and the duration of the discharge. The biota in the Liberator field is not expected to be particularly sensitive to chemical or hydrocarbon discharges. Chemicals identified for use at the Liberator field will be selected for their low toxicity wherever possible. Fluids and associated chemicals returned from the wellbores and flushed from the pipelines will be treated on the rig topsides to ensure the oil in water concentration is <30 mg/l prior to discharge, and this treatment will tend to remove oil-based chemicals. The chemicals that are eventually discharged will be rapidly diluted in the water column. Bakke et al. (2013) suggests that the majority of effects observed 100

101 from the release of drilling muds is physical stress, although chemical toxicity cannot be ruled out. Effects are expected to be restricted to a radius of 1 2 km from the discharge point (Bakke et al., 2013). Chemical use and discharge will be permitted under the Offshore Chemical Regulations, and the permitting process will require an individual risk assessment for each chemical prior to discharge. Hydrocarbon discharge within the produced water stream will be managed in line with current Bleo Holm processing and will not exceed permitted levels. Mitigation A number of management and mitigation measures will be adopted by i3 Energy to reduce, where possible, the potential impacts of Project discharges to sea: Maximise efficient use and recovery of drilling mud; No discharge of LTOBM or LTOBM contaminated cuttings to sea; A rig audit will be conducted to ensure rig is in compliance with all relevant guidelines and legislation; Environmental risk assessment as part of Offshore Chemical Regulations approval process, and identification of measures to reduce risk including chemical selection procedures, will be carried out to obtain approval for chemical use prior to operations commencing; Oil in water discharge will be within the existing permitted limits for the Bleo Holm FPSO, as follows: o A maximum monthly average of oil (dispersed) in water content of 30 mg/l or less; o The maximum concentration not to exceed 100 mg/l at any time; and o Quantity of dispersed oil in produced water discharged must not exceed 1 tonne in any 12 hour period. Seasonal sensitivities of potential receptors are not considered to be sufficiently variable to mean seasonal mitigation commitments are of value. Cumulative and in-combination impact assessment Discharges to sea during the Project will occur intermittently and will be short-term. Drilling discharges will occur between April 2018 and August 2018, and subsea infrastructure installation and commissioning discharges will occur by the end of August The limited quantities of material discharged, the intermittent nature of the discharge and the proposed mitigation measures are likely to limit the potential impacts. Although there is no confirmation at the time of writing, there may be other well drilling programmes or field development activities planned for the same period as the Liberator Phase 1 Field Development. Given the limited impact expected from the Liberator Phase 1 Field Development, the development will not contribute significantly to cumulative impacts associated with discharges to sea from other projects. 101

102 There are a number of other producing oil and gas fields within and close to the North Sea area in which Liberator sits, and some of these will be discharging chemicals and hydrocarbons to sea via produced water discharge; this includes fields producing through the Bleo Holm FPSO. The extremely limited additional chemical and hydrocarbon discharge expected as a result of production from the Liberator field coming online means that cumulative impacts with other existing developments is not expected. Transboundary impact assessment The Liberator field is located 171 km away from the closest (UK/Norway) transboundary line. Given the limited impacts expected, it is extremely unlikely that there will be any transboundary impact from the proposed operations. Decommissioning There will be limited potential for decommissioning activities to negatively impact the marine environment through discharges to sea. It is possible that there may be some re-suspension of deposited cuttings during the removal of wellhead infrastructure but recovery and recolonisation would be expected to occur rapidly. The mitigation measures described in this chapter with respect to selection and optimisation of chemical use will also apply to the decommissioning process and chemical risk assessments will be conducted in line with the applicable regulations at the time. Considering the above, the potential impacts from decommissioning are thus likely to be no greater in magnitude to those experienced during drilling and installation and thus not significant. Protected sites The conclusions on the impacts presented in this chapter have taken account of protected sites as relevant. It is important to note, however, that discharges associated with the Liberator Phase 1 Field Development will not occur within any SAC, SPA, NCMPA or MCZ. It is considered unlikely, given the small scale of the proposed development, that the discharges will spread far enough to interact with any protected or proposed protected areas, the closest of which is the proposed Southern Trench MPA located 36 km away. As such, there is considered to be no Likely Significant Effect on SACs, SPAs, NCMPAs and MCZs and hence no impact on any conservation objectives or site integrity. Seabed impacts from discharges to sea are discussed in Section 5.3, and therefore the FEAST tool has not been used in this section. 102

103 Residual impact Receptor Sensitivity Vulnerability Value Magnitude Biological features of the water column Low Low Low Minor Rationale The information in the Environment Description (Section 3) has been used to assign the sensitivity, vulnerability and value of the receptor as follows. Inhabitants of the water column around the discharge locations will have some tolerance to accommodate the effects of increased sediment load and sensitivity is considered low, with no particularly sensitive species known to use the area. As potential impacts are not likely to affect the long term function of a system or a population, there will be no noticeable long term effects above the level of natural variation experienced in the area and vulnerability is low. The fish populations in the Project area are characterised by species typical of the central North Sea, with some spawning and nursery regions for commercially important fish and shellfish species occurring in the vicinity of the Project area. There appear to be low densities of marine reptiles, cetaceans and seals within the Project area. There are no designated or proposed sites of conservation interest in the Project area. None of the survey work undertaken in the Project area has identified any habitats or species that are of specific conservation significance. Value is therefore defined as low. The impact magnitude is minor because any chemicals that may be discharged will be negligible in volume and have a low marine toxicity ranking. The total volume of hydrocarbons that may be discharged during operational is very low, and will be at concentrations below recognised marine discharge toxicity thresholds. Consequence Low Impact significance Not significant. 5.3 Seabed Disturbance Description and quantification of impact The drilling of both wells will be conducted using a semi-submersible drill rig. The rig will be moored using 8 anchors. The maximum anchor spread radius will be 2,500 m. The anchors will be connected to the drilling rig by anchor chains, of which approximately 1,000 m of each chain is expected to lie on the seabed during drilling operations. A small area of seabed where each anchor is placed will be compressed as the anchors sink into the seabed. Consequently, the placement of the anchors will cause localised direct damage to the habitats and species at the point of placement, whilst the movement of the anchor chains as they sweep back and forth across the seabed will affect the benthos for as long as the anchor chains remain in position. Physical disturbance is also likely to be caused during installation of the wellheads, pipeline, umbilical, spools and jumpers as well as by mattresses and rock laid for crossing and protection purposes. These items can cause mortality or displacement of benthic species in the direct footprint of the disturbance. Table 5-3 quantifies the area of seabed that may be directly and indirectly impacted by the Project through disturbance or covering of the seabed by temporary or permanent infrastructure. As a precautionary estimate, it has been assumed that sediment 103

104 re-suspension and settlement will occur within an area twice that of the direct footprint. This approximation has been adapted from Rogers (1990) where indirect disturbance from dredging was reported to affect an area approximately six times larger than the direct impact area. The seabed current regime in the Liberator field is relatively quiescent and any sediment particles are likely to settle quickly. Although finer particles may remain suspended for some time before resettling, the relatively low bottom currents in the Liberator field suggest they will not be carried particularly far. An indirect impact area of twice the direct impact area is therefore expected to be appropriate. In addition to interference with the seabed through temporary and permanent introduction of equipment, further seabed disturbance may be caused by the distribution of material from the wellbores onto the seabed. As outlined in Section 5.2, the Project will be developed by the drilling of two wells. The first two sections of each well (36" and 17½") will be drilled before a marine riser is installed. This means that all drilling fluids, rock cuttings and residual cement returns from these two sections will be discharged directly onto the seabed in the immediate vicinity of the wells. The deeper sections of the well (the 12¼ꞌꞌ and 8½" sections) will be drilled with a marine riser in place, meaning material will be returned to the drilling rig. Both sections may be drilled using WBM, in which case cuttings will be separated from the mud at the platform topsides and discharged overboard. The 12¼ꞌꞌ section may alternatively be drilled using LTOBM, in which case no discharge will occur from this section. An estimate of the drill cuttings and WBM that will be generated/used and subsequently discharged to sea for one well is presented in Table 5-4. The discharges for both wells combined are discussed in the text below. 104

105 Table 5-3 Predicted areas of direct and indirect long-term and short-term seabed impact Short-term disturbance of the seabed Parameter Direct area (km 2 ) Indirect area (km 2 ) Anchors at L Anchors at L x 2.5 km chains at L1, each abrading an area of seabed assumed to be 1,000 m x 10 m x 2.5 km chains at L2, each abrading an area of seabed assumed to be 1,000 m x 10 m Total short-term Long-term presence of infrastructure on the seabed (note that the indirect area of disturbance will be temporary) L1 subsea tree and protection structures (7.87 m x 7.87 m) L2 subsea tree and protection structures (7.87 m x 7.87 m) Buried pipeline of 2 km length with assumed trenching width of 1 m Buried umbilical and gas lift line of 2 km length with assumed trenching width of 1 m Crossing (assumed to be 100 m x 10 m) x production, umbilical and gas lift spools (100 m x m each) covered by a total of 153 mattresses (6 m x 3 m). Rock placement to prevent upheaval buckling (estimated 5 berms required of 20 m x 2 m each) Total long-term Total Table 5-4 Estimate of cuttings and WBM discharged from one well Cuttings generated WBM discharged Section Discharge point (tonnes) (tonnes) 36ꞌꞌ Seabed ½ꞌꞌ Seabed ¼" Drilling rig topsides (for WBM option only) ½" Drilling rig topsides Total 1,000 2,025 The figures in Table 5-4 indicate that for both wells combined, a total of 6,050 tonnes of mud and cuttings will be discharged to sea, with 2,750 tonnes deposited straight to the seabed (for 105

106 the 36" and 17½" sections) and up to 3,300 tonnes discharged overboard from the drilling rig. In addition to drill cuttings, it is expected that for both wells combined, up to 216 tonnes of excess cement will be discharged to the seabed during cementing operations. It is not possible with the available data to predict exactly what the dimensions of any area of disturbance will be. Experience suggests that the disturbed area is likely to consist of a clearly defined central mound of drill cuttings and mud around each wellhead, extending no more than 50 m from the wellhead. The maximum height of the central pile is likely to be in the region of 1 2 m close to the wellhead, reducing to around 0.1 m no more than 50 m from the wellhead. Outside this central area there is likely to be a wider area that is subject to very light levels of deposition which are expected to be hard to detect bathymetrically. WBM, cement and cuttings that are discharged to the seabed are not expected to cause significant toxic effects. Potential effects are expected to be crushing, smothering and habitat loss. These impacts are the same as those expected for the other types of seabed disturbance discussed above, and the potential impacts from both sources are therefore discussed together below. The significance of direct habitat loss or mortality of sessile seabed organisms 13 depends on the footprint of the area of disturbance, the level of tolerance of the affected habitat and species to direct disturbance, the conservation value of the affected habitat or species and the uniqueness of the affected habitats or species assemblages to the area. At the source of disturbance, fauna may be crushed and injured or killed by the placement of structures, rock or mattresses, or by the discharge of consolidated material (like cement) from the wellbore. Mobile epifauna may move away from the impacted area; sessile epifauna and infauna are therefore more likely to be impacted. More mobile species of infauna may be able to work their way back through layers of deposited to the surface. If sedimentary habitat is covered by impenetrable material for the long term (for example by rock placement or a structure such as a manifold), that area of habitat is lost for use by the indigenous marine fauna, although it may provide additional habitat for epifauna that require a hard attachment point, leading to a slight change in the species distribution in the area. In addition to habitat loss and direct mortality and injury caused by crushing or burial, further impacts such as smothering of benthic species and habitats may be caused by re-suspension and re-settlement of seabed sediment, and discharge of material from the wellbore to the seabed. Rock placed on the seabed, installation of subsea facilities, especially the trenching of the pipeline and umbilical/gas lift line, and installation and retrieval of anchors associated with the drill rig is likely to result in some sediment suspension and re-settlement. Exposure to higher than normal loads of suspended sediment has the potential to negatively affect habitats and species in adjacent areas that are not directly damaged by crushing and burial. The resettlement of sediments can result in the smothering of epifaunal benthic species (Gubbay, 13 Sessile refers to an organism that is anchored to a substrate, and which cannot move about freely. 106

107 2003), with the degree of impact related to their ability to clear particles from their feeding and respiratory surfaces. Obligate filter feeding organisms (for example hydroids and bryozoans) that rely on suspended particles for food may be more vulnerable to potential smothering impacts than deposit-feeding organisms. Filter feeding structures may become clogged with increased suspended solids in the water column just above the seabed and therefore feeding could be temporarily limited. The sea pens present in the area (P. phosphorea and Virgularia sp., Gardline, 2013b) may be vulnerable to this type of impact, although both P. phosphorea and V. mirabilis are capable of withdrawing into the sediment when disturbed, which may reduce intolerance and improve recoverability (Hill and Wilson, 2000; Jones, 2008). Defra (2010) states that impacts arising from sediment re-suspension are short-term (generally over a period of a few days to a few weeks), Due to the short-term and one off nature of drilling activities, any increase in suspended solids near the seabed is not expected to persist for more than a day following cessation of operations. After deposition, particulate material on the seabed will be subject to re-distribution through the action of seabed currents. In the southern North Sea, where seabed currents are more energetic, drill cuttings piles often do not persist as they are rapidly re-suspended and redistributed over a wide area. In the Liberator field, however, seabed kinetic energy is considered low (McBreen et al., 2011) and it is therefore expected that re-distribution by water currents will be a very gradual process. In areas that have received a thin covering of additional material, either from re-suspension of seabed sediments or from deposition of material from the wellbore, it is expected that deposited material will be worked in to the existing seabed sediments by sediment reworkers, thereby gradually returning the seabed to a condition similar to its unimpacted state. The actions of sediment reworkers are unlikely to make a discernible difference to any cuttings piles however. Recolonisation of impacted areas is expected to occur from populations in the surrounding area. Hard-surfaced items such as manifolds or areas of rock are likely to become colonised through larval attachment from the water column, and will eventually support a fauna distinct from that found in the surrounding sediments. Any drill cuttings piles that are formed will also be colonised, but these too will likely show some differences from the fauna supported by the surrounding sediments. The mix of WBM, cuttings and set cement is not expected to be toxic, but it will have a different particle size distribution and present a different bathymetric profile to the surrounding area, encouraging colonisation by different species, or at least with different species being dominant. In conclusion, there will be direct impacts to the benthic community, however most of the affected area will only be impacted temporarily, with recolonisation from the surrounding area and from the water column driving a swift recovery. There will be a very small area that will experience a long-term change in the distribution of species present, but this area is negligible when compared to the available similar habitat in the surrounding area. There were no protected habitats identified in the Project area during seabed surveys, and the sediment type within the Project area is widespread in the surrounding area, suggesting that the sensitivity of the benthos in the area is low and the potential for recovery following disturbance is high. 107

108 It is possible that there will be existing drill cuttings accumulations from previous wells located around the Blake manifold. Disturbance of these cuttings accumulations during Liberator Phase 1 Field Development could cause further small impacts on the seabed via smothering as described above. Mitigation of this potential impact is described in Mitigation A number of management and mitigation measures will be adopted by i3 Energy to reduce, where possible, the potential impacts of the Project on benthic habitats and species: A detailed anchor pattern for the drilling rig will be developed prior to mobilisation; this will take account of any environmental sensitivities identified close to the drilling locations; Should the drill rig need to leave the site, for example due to a break in activity over winter, on its return the same anchor pattern will be used where possible to minimise the area of seabed disturbed; The volumes and locations of rock and mattress protection will be refined during Detailed Design to reduce the footprint on the seabed to the extent practicable; During rock placement activities a fall pipe system held a few metres above the seabed will be used to ensure accurate placement and minimise the area of seabed disturbed; The pipeline, umbilical and gas lift line may be installed in the same trench if considered technically feasible, this will be considered in future design work; and Any drill cuttings accumulations near the Blake manifold will be identified prior to commencing drilling operations; installation work will be routed to avoid any accumulations and prevent re-suspension of cuttings material. Seasonal sensitivities of potential receptors are not considered to be sufficiently variable to mean seasonal mitigation commitments are of value. Cumulative and in-combination impact assessment DECC (2009) identifies that the sources of cumulative physical disturbance to the seabed associated with oil and gas activities include drill rigs, wellhead placement and recovery, subsea template and manifold installation, umbilical and pipeline installation and trenching and decommissioning of infrastructure. Of these, pipelay is considered to account for the largest spatial extent. The Liberator Phase 1 Field Development is predicted to cause direct disturbance of 0.17 km 2 and indirect disturbance of 0.34 km 2 of seabed. The majority of this area is likely to be affected only in the short term, and the area affected is extremely small compared to available similar habitat in the vicinity of the Project. As illustrated in Section 3.5.1, there are a number of established oil and gas fields in proximity to the Liberator field (including the Blake and Ross fields), but the ongoing seabed impacts caused by these projects is likely to be very small (i.e. installation has been completed and ongoing operational impacts on the seabed are minimal). The most damaging activity taking place in the area is almost certainly use of bottom-fishing gear by fishing vessels. This is highlighted by the OSPAR background documents for A. 108

109 islandica (OSPAR, 2009) and seapen and burrowing megafauna communities (OSPAR, 2010), both of which identify beam trawling / bottom trawling as the main threat to the species / habitat assessed. In contrast, OSPAR (2010) identifies habitat loss through infrastructure development, including offshore oil and gas, as a low scale threat. Fishing vessels spent 762 days trawling and 19 days dredging in ICES rectangle 45E8 in The majority of landings 92% of the total landed weight were of demersal species (Scottish Government, 2016), indicating the majority of the trawling days recorded comprised bottom-trawling. In comparison with the seabed disturbance caused by this activity, impacts from the Liberator Phase 1 Field Development will be negligible, and make an insignificant contribution to any cumulative impact. Transboundary impact assessment The Offshore Energy SEA for UKCS waters (DECC, 2009) states that seabed impacts are unlikely to result in transboundary effects and even if they were to occur, the scale and consequences of the environmental effects in the adjacent state territories would be less than those in UK waters and would be considered unlikely to be significant. Liberator is located approximately 171 km from UK/Norway median line; direct and indirect seabed impacts will not extend this far from the Project and transboundary impacts will not occur. Decommissioning Any potential impacts that decommissioning operations (e.g. removal of Liberator infrastructure) may have through seabed disturbance will occur in an area that already experienced seabed disturbance during the installation operations. The potential impacts from decommissioning operations are likely to be similar in magnitude to those experienced during installation and thus not significant. Protected sites Marine Scotland s FEAST tool indicates that the habitat features expected in the area may show a low to moderate sensitivity to increased levels of siltation, a moderate to high sensitivity to change in seabed type and a moderate sensitivity to surface and sub-surface abrasion and penetration. Habitat assessment conducted in the Project area identified low densities of the seapens P. phosphorea and Virgularia sp., as well as numerous faunal burrows. The density of both features was too low to qualify as the protected habitat seapen and burrowing megafauna community identified in OSPAR (2008). Whilst the seabed may be consistent with the PMF and MPA search feature Burrowed mud, extensive search areas for this feature have already been designated in the North Sea, and none of them correspond with the Liberator Phase 1 Field Development. It is therefore unlikely that the Liberator Phase 1 Field Development will have a significant impact on the PMF. As such it is considered unlikely that the sensitivities indicated by the FEAST tool would translate to a significant impact on any protected sites or features. An assessment of the site s potential as a herring spawning ground found there was no potential for herring spawning in the Project area (Gardline, 2013b). 109

110 Residual impact Receptor Sensitivity Vulnerability Value Magnitude Benthos Low Low Negligible Minor Rationale The information in the Environment Description (Section 3) has been used to assign the sensitivity, vulnerability and value of the receptor as follows. The sensitivity of seabed habitats and species to disturbance is expected to be low, with an absence of protected species / habitats and wide availability of similar habitat in the surrounding area. Disturbance is expected to be extremely localised, with very limited impacts on a faunal community that is expected to show low sensitivity to disturbance and rapid recovery. Most impacts are expected to be short term, with prolonged impacts occurring over a very limited area. The Project activities are expected to be negligible in terms of cumulative and in-combination impacts. Mitigation measures will be used to further reduce the level of impact. Consequence Low Impact significance Not significant 5.4 Underwater Noise Introduction Description and quantification of impact Underwater sound is generated by natural sources such as rain, breaking waves and marine life, including whales, dolphins and fish (termed ambient sound). Industrial use of the marine environment adds additional sound from numerous sources including shipping, oil and gas exploration and production, aircraft and military activity. In this assessment, sound is used as a term for anything that an individual animal can hear. The term noise is used in this assessment to mean sound that may have some form of potential impact (for example, it may affect behaviour). Whilst all noise is also sound, not all sound is considered noise. Many species found in the marine environment use sound to understand their surroundings, track prey and communicate with members of their own species. Some species, mostly toothed whales, dolphins and porpoise, also use sound to build up an image of their environment and to detect prey and predators through echolocation. Exposure to natural sounds in the marine environment may elicit responses in marine species; for example, harbour seals have been shown to respond to the calls of killer whales with anti-predator behaviour (Deecke et al., 2002). In addition to responding to natural sounds, marine species such as fish and marine mammals may also respond to man-made sound. The potential impacts of industrial noise on species may include impacts to hearing, displacement of the animals themselves and potential indirect impacts which may include displacement of prey species. Whilst there is a lack of species specific information collected under controlled or well-documented conditions, enough evidence exists for fish and marine mammals to suggest that sound may have a potential biological impact and that noise from man-made sources may affect animals to varying degrees 110

111 depending on the sound source, its characteristics and the susceptibility of the species present (e.g. Nowacek et al., 2007, report this specifically for cetaceans). As well as potential behavioural impacts of noise, marine mammals and fish exposed to an adequately high sound source may experience a temporary shift in hearing ability (termed a temporary threshold shift; TTS) (e.g. Finneran et al., 2005). In some cases, the source level may be sufficiently high such that the animal exposed to the sound level might experience physical damage to the hearing apparatus and the shift may not be reversed; in this case there may be a permanent threshold shift (PTS) (Southall et al., 2007), and the animal could be considered as being injured. Noise sources that have been identified as likely to occur during the Liberator Phase 1 Field Development and which, depending on the specific nature of the sources, could cause injury or disturbance to marine mammals and fish are limited to vessel use and limited VSP activity, as outlined in Section 2. The drill rig will use anchors to maintain station and there is thus no requirement for ongoing use of dynamic positioning Vessels and marine mammals Noise emissions from vessels occur continuously during operation of the vessel, appearing louder as animals approach the vessels, and appearing quieter as animals move away. Such continuous noise sources are generally of less concern than intermittent sources (e.g. such as seismic conducted during exploration activities) where relatively high doses of noise can be received by animals over a very short period of time with little warning. In terms of the typical noise emissions from the vessels to be deployed in the installation activities, a review of the literature suggests that they will be in the range db re 1 1 m (e.g. Hannay et al., 2004, MacGillivray and Racca, 2006, McCauley, 1998). Published thresholds at which injury (defined as permanent shift in hearing ability) might occur for marine mammals (Southall et al., 2007) suggest that noise emissions of in excess of 215 db re 1 1 m would be required for injury to occur VSP and marine mammals Sound emissions from VSP activity could theoretically cause injury to marine mammals, given that a review of peak emissions from such activity suggests they could be above the Southall et al. (2007) proposed threshold of 230 db re 1 1 m. However, sound emissions from VSP activity are typically considered to be less problematic for marine mammals than for other forms of seismic activity, since there is generally only a single, small airgun deployed (JNCC, 2010). Additionally, VSP activity for the Liberator Phase 1 Field Development is only expected to last for 36 hours per well, further reducing the potential to significantly disturb marine mammals Fish Popper and Hawkins (2014) outline the possibility of fish being affected by various noise emitting industries, of which oil and gas is one. In the same way as marine mammals can be affected, it is possible that fish could be injured or disturbed if noise emissions are sufficiently high (e.g. De Robertis and Handegard, 2012). However, installation and support vessels will be slow moving and fish will not experience any sudden bursts of sounds, such that they may choose to move away, thus avoiding injury. For VSP, the emissions could be considered 111

112 intermittent (even if the noise source is continuous), but the sound levels are likely to be low. Even if some fish were to be injured by the emissions, many millions of individuals make up most species populations (e.g. Mood and Brooke, 2010) and limited injury is not likely to result in significant impacts at the population level. Similarly, should the noise emissions disturb fish, the short-term movement away from the short-term activities would not constitute a largescale movement by individuals of a species and would be highly unlikely to result in population level impacts. Mitigation The primary measure of reducing potential impact will be to limit the duration of the noise emitting activities; for example, vessels will only be deployed where necessary and limited as far as is practicable during installation activities. i3 Energy will adhere to JNCC guidelines for reducing the potential for injury and disturbance to marine mammals from VSP activity (JNCC, 2017), which include: A suitably trained marine mammal observer (MMO) will conduct a pre-shooting search over a 30 minute period prior to the commencement of VSP. This will involve a visual assessment to determine if any marine mammals are within a 500 m monitoring zone (measured from the location of the VSP). Should operations cease for ten minutes or more, a search will be undertaken before the re-commencement of activities; Should any marine mammals be detected within 500 m of the VSP operations, these operations will be delayed until marine mammals have moved outside the mitigation zone. In this case, there will be a 20 minute delay from the time of the last marine mammal sighting to the commencement of activities; The VSP will be powered up slowly over 20 minutes in order to give marine mammals time to leave the area. Build-up of power will occur in uniform stages to provide a constant ramp-up in amplitude. These soft start procedures will also be undertaken if the operations are stopped for at least 10 minutes, to allow for checking of the visual observation zone to determine if any marine mammals have entered the area whilst the VSP activities were suspended. If marine mammals have re-entered the observation zone, restart of the operations will be delayed until 20 minutes after the last sighting of the marine mammal; and If VSP is required to commence in sub-optimal conditions for visual monitoring, consideration will be given to using passive acoustic monitoring (PAM) in addition to MMOs. Use of PAM in conditions that are sub-optimal for visual monitoring enhances the probability of detecting marine mammals (when vocalising), reducing the likelihood of potential negative impacts. Seasonal sensitivities of potential receptors are not considered to be sufficiently variable to mean seasonal mitigation commitments are of value. 112

113 Cumulative and in-combination impact assessment It is possible that the various noise sources associated with the Liberator Phase 1 Field Development activities (i.e. multiple vessels operating at the same time, or VSP occurring at the same time as vessels being used) could result in an impact to marine mammals and fish. However, noise levels will be sufficiently low that injury is not expected for marine mammals. Potential disturbance zones are likely to be small and, for the most part, highly limited in temporal extent. For fish, the potential for injury or disturbance to result in any detectable changes at the population level is very low. Cumulative impact from sources within the Liberator Phase 1 Field Development are therefore not expected. In the context of the number of vessels that use the North Sea for fishing, shipping, passenger transport, oil and gas activity, recreation and others, which will all emit noise, the scale of the additional in-field time required for vessels associated with the Liberator Phase 1 Field Development is clearly limited (see Section 2.7). In theory, any project that regularly emits underwater noise has the potential to act cumulatively with the Liberator Phase 1 Field Development this includes the ongoing operation of the Bleo Holm FPSO. Cetacean and fish populations are free-ranging and longdistance movement is likely to be frequent, and in some cases predictable through seasonal migration (e.g. mackerel; ICES, Undated). Any animal experiencing a noise from the Liberator Phase 1 Field Development is likely to belong to a much wider ranging population and there is the potential for that same animal to subsequently come into contact with noise from activates related to other unrelated projects. However, potential injury and disturbance impacts resulting from any individual element of the Liberator Phase 1 Field Development are not expected to be significant (e.g. animals will not be excluded from the area), and significant cumulative impact from an animal encountering noise emissions from multiple activities within a short period of time is therefore considered highly unlikely. Transboundary impact assessment The Liberator field is approximately 171 km from the UK/Norway median line. Given the noise sources involved in the project, direct transboundary impact from noise emissions will not occur. However, marine mammals and fish are free-ranging animals and any impact that occurs in UK waters is likely to occur on animals that belong to a much wider ranging population and thus likely to cross median lines. Such a potential impact could qualify as a transboundary impact. However, since injury and disturbance from the limited operations associated with the Liberator Phase 1 Field Development are not expected to result in significant impact to any population, potential transboundary impacts are also therefore considered not significant. Protected sites As described in Section 3, only one species listed on Annex II of the Habitats Directive is likely to occur in the Liberator field; this is the harbour porpoise (bottlenose dolphin are generally found only within the 20 m depth contour). For harbour porpoise, animals making use of the Southern North Sea candidate SAC may also make use of the Liberator field; harbour porpoise within the North Sea are known to form one biogeographical population that spans the North 113

114 Sea as a whole (JNCC, 2015). However, there is expected to be no injury to harbour porpoise from the Project activities, and no effect of disturbance at the population level. As such, there will be no Likely Significant Effect on this protected site. It is possible that vessel transits nearshore could overlap with bottlenose dolphin and grey and harbour seal use of an area (i.e. the other Annex II marine mammal species found in the UKCS), but the presence by vessels in such areas would be highly limited in temporal extent and there would be no significant effect on any nearby protected sites. This assessment also considers there to be no potential for underwater noise emissions to interact with protected features of an NCMPA or MCZ (primarily as there are no sites designated for features that may be affected by noise emissions close to the Liberator field) and there is therefore no significant risk to the conservation objectives of any NCMPA or MCZ. The FEAST tool indicates that the seabed habitats expected in the area are not sensitive to noise disturbance Vessels Residual impact Noise emissions from vessels are not expected to cause injury. However, they may be sufficiently loud for marine mammals to find the noise a nuisance and to remove themselves from the area for the duration of activities. Such exclusion might be considered significant if it occurred for extended periods of time in areas that were important for breeding or feeding (which does not apply to the Liberator field; see Section 3). Southall et al. (2007) note that behavioural reactions to noise by marine mammals are by no means consistent across species or individuals, and it is difficult to therefore state specific thresholds for impact. However, considering published data on noise emissions from vessels against possible thresholds for disturbance (e.g. NMFS, 2005, Southall et al., 2007) it is clear that there is the potential for animals to be disturbed to some degree. It is important to note that behavioural changes such as moving away from an area for short periods of time, reduced surfacing time, masking of communication signals or echolocation clicks, vocalisation changes and separation of mothers from offspring for short periods, do not necessarily imply that detrimental effects will result for the animals involved (JNCC, 2010b). Temporarily affecting a small proportion of a population for a limited period of time would be unlikely to result in population level effects and would be considered to be trivial. In contrast, affecting a large proportion for a long period of time may be considered non-trivial. The majority of vessels will be on site for a matter of a few days; the only vessel that will remain longer will be the drilling rig, but this will be anchored during drilling. In the context of low number of marine mammals likely to be found in the Liberator field, the likelihood of significant disturbance is low. There will be vessel use in nearshore waters as vessels transit to and from the offshore field but the time spent in nearshore waters will be extremely limited and the likelihood of significant disturbance is low VSP With the mitigation measures that will be used for the VSP (Section 5.4.2), the potential impact zone for injury to cetaceans and pinnipeds is expected to be eliminated, since there would be no marine mammals within 500 m of the sound source. 114

115 The only potential impact that could therefore potentially occur is through changes to behaviour, within a few hundred metres of the VSP source. However, it is unlikely that many, if any, marine mammals would be present within the zone during operations, not least because VSP would not commence if there were any marine mammals identified within the zone. The small potential impact zone means that the noise emissions would not represent a barrier to wider, regional movements of marine mammals. In addition, VSP activity at a well would be likely to extend to only 36 hours. With only two wells in the development, VSP would, in a worst case, last for only 72 hours over the approximately 138 days during which drilling will be conducted Fish In terms of the potential impacts on fish, a review of published potential impact zones from continuous and pulsed sound suggest they are likely to be limited to tens or hundreds of metres from the noise source, if any responses do occur (e.g. De Robertis and Handegard, 2012, Chevron, 2013, Mueller-Blenkle et al., 2010, Schulze and Ring Pettersen, 2007). Whilst estimates of fish populations are generally not available, it is likely that many millions of individuals make up most species populations (e.g. Mood and Brooke, 2010). The injury to small numbers of fish would not constitute a large scale reduction in population and the movement of fish tens or hundreds of metres away from a vessel or VSP activity would not constitute large scale movement by individuals of a species (in any case, fish are constantly moving from location to location). As such, vessel noise and VSP would be highly unlikely to result in population level impacts. Residual impact Receptor Sensitivity Vulnerability Value Magnitude Marine mammals Low Low Low Minor Fish Low Low Negligible Minor Rationale The information in the Environment Description (Section 3) has been used to assign the sensitivity, vulnerability and value of the receptor as follows. Both receptor groups have some tolerance to accommodate the limited effects that vessel use and very restricted VSP activity could give rise to (i.e. no injury but some minor disturbance within a few hundreds of metres of the source) and are ranked as low in terms of sensitivity. As there is expected to be no change at the population level for either receptor group, the impact is not likely to affect long term function or status of any population and the vulnerability can also be considered low. In terms of value, marine mammals found at the site are considered for protection under European legislation but as they do not belong to protected sites around the Project area they can be classed as low value. For fish, species found at the site are generally abundant around the UKCS and are not afforded any specific conservation protection. As such, they can be classed as negligible value. For magnitude, any possible impact on either receptor group is expected to be highly localised in scale and of a temporary nature. On this basis, a magnitude of minor is assigned. Consequence Low Impact significance Not Significant 115

116 5.5 Other Sea Users Description and quantification of impact As discussed in Section 3.5, the proposed development is in an area of low shipping density, with no military activity, oil and gas development, renewables developments, cables or pipelines in close proximity, with the exception of the existing Blake and Ross fields. As such, the only receptor expected to be affected by the proposed development is commercial fishing vessels. Temporary and life of field exclusion Whilst each well is being drilled, a temporary safety zone of 500 m will be maintained around each drilling site. The purpose of this safety zone is to ensure the safety of all personnel involved in the drilling activities and to minimise the risk of collisions between the vessels involved with the drilling activities and other vessels in the area. Following the drill rig going off site, an exclusion zone of 500 m radius around the L2 well will be maintained throughout the anticipated seven year life of the Liberator Phase 1 Field Development. The purpose of this safety zone is to limit the potential for interaction between the subsea infrastructure and demersal fishing gear. The L1 well will be located within an existing 500 m exclusion zone that protects the Blake Development. The pipelay, rock placement and associated support vessels will exclude other sea users around their immediate vicinity but only for a very short period of time (60 days maximum). Given that fishing intensity in the area has been estimated to be low (Scottish Government, 2016), a negligible impact on the fishing sector is expected. Snagging risk Interrogation of data from The Marine Accident Investigation Branch shows there have been 15 sinkings resulting from snagged fishing gear between 1989 and 2014, resulting in 26 fatalities. There is potential for fishing gear to snag on the well trees or the new pipeline, umbilical and gas lift lines. To minimise snagging risk, both well trees will be protected by fishing friendly protection structures, and the pipeline, umbilical and gas lift line will be buried in trenches and, where necessary, covered by rock placement. Mattresses will protect the areas where the pipeline, umbilical and gas lift line exit the trenches. There is the potential for the formation of mounds on the seabed due to the deployment and recovery of the drill rig anchors. Over-trawling such anchor mounds with fishing gear could result in sediment being retained in fishing nets, with potential damage of nets and equipment and affecting catches, as well as posing a threat to the safety of the vessel. These mounds are most likely to form in areas where sediments at or near the surface contain heavy clay. The seabed sediments across the majority of the Liberator field comprise silty sand, with occasional clay outcrops. Consequently anchor mounds in the Liberator field are likely to persist only in the short term. Trenching in clay soils may give rise to clay berms at the edges of trenches, which may pose a hazard to fishing vessels. There is at least one recorded incident of a fishing vessel being sunk in the North Sea following snagging of gear on a clay trenching berm (Marine Accident 116

117 Investigation Branch, 2006). Surveys of the development area (Gardline, 2006) indicated occasional clay occurring outcrops, although it is not known whether any of these are on the proposed route between Well L1 and Well L2. Mitigation A number of mitigation measures will be employed to reduce the impact on other sea users: During installation the number of vessels and length of time they are required on site will be reduced as far as practicable through careful planning of the installation activities; A safety zone of 500 m in radius will be established around the drill rig during drilling and around each drill centre for the life of the Liberator Phase 1 Field Development; A standby and support vessel will operate during the period that the drill rig is in place. These vessels will ensure that other sea users are aware of the presence of the anchor spread outside of the drill rig safety zone; Information on the location of subsea infrastructure and vessel operations will be communicated to other sea users (via the United Kingdom Hydrographic Office) through the standard communication channels including Kingfisher, Notice to Mariners and Radio Navigation Warnings; Infrastructure will be marked as hazards on admiralty charts and entered into the Fishsafe system so that it may be avoided by fishing vessels; Consultation will be undertaken with relevant authorities and organisations with the aim of reducing potential interference impacts resulting from Project activities as far as practicable. A fishery liaison strategy will be developed and implemented; Regular maintenance and pipeline, umbilical and gas lift route inspection surveys will be undertaken; Subsea tree protection structures will be designed to be fishing friendly, and will be in place at Well L2 during its period of suspension; The majority of the pipeline, umbilical and gas lift line will be buried, eliminating snag risk (the lines will exit trenches close to each end of the route); Should wells be abandoned, wellheads will be cut off below the seabed leaving the seabed free of infrastructure that could pose a snagging risk to fishing gear; and Trenching will be conducted using a water jet to slurrify the sediment and allow the pipeline, umbilical and gas lift line to sink into the seabed without removing material from the trench, therefore no berm will be created that could create a snagging hazard. Seasonal sensitivities of potential receptors are not considered to be sufficiently variable to mean seasonal mitigation commitments are of value. 117

118 Cumulative and in-combination impact assessment Due to the low levels of shipping activity in the Project area, the wide expanse of water available to navigate in, the limited number of vessels to be deployed for the installation activities and since there will be no additional surface infrastructure installed (i.e. the Liberator field will tie-back to the existing Bleo Holm FPSO), it is not anticipated that there will be any significant cumulative impacts with respect to vessel collision risk. DECC (2009) report that exclusion from an area and snagging risk from oil and gas activities are cumulative to those resulting from natural obstructions, shipwrecks and other debris. However, the area of seabed exclusion during the life of the Liberator Phase 1 Field Development will be small in comparison with the total fishing area available and will be largely temporary and thus the impact is likely to be low. Moreover, there are estimated to be 457 safety zones in the central and northern North Sea on the UKCS (UKOilAndGasData, 2017) and this project will add only one exclusion zone to an area where fishing intensity is low and where fishermen are used to responding to ongoing oil and gas production. Consequently, there is not expected to be a significant cumulative impact. Transboundary impact assessment The area in which the Project is located is regularly fished by vessels of other nations and any effect on their landings could constitute a transboundary impact. However, the potential impact on fisheries is considered not significant and it is therefore unlikely that the Project will result in any transboundary impacts. Decommissioning Any potential impacts on other sea users regarding collision risk and temporary exclusion from the Project area that decommissioning operations may have will occur at a similar level to impacts during installation operations. Removal or appropriate decommissioning in situ of Project infrastructure during decommissioning will act to remove any potential snag risk. 118

119 Residual Impact Receptor Sensitivity Vulnerability Value Magnitude Fisheries Low Low Low Minor Other sea users, except fisheries Negligible Negligible Negligible Minor Rationale The information in the Environment Description (Section 3) has been used to assign the sensitivity, vulnerability and value of the receptor as follows. Fisheries are expected to be tolerant to short-term interference (low sensitivity) and given the low intensity of fishing in the area, it is unlikely that drilling activities or long-term exclusion zones around the wells will have an impact on the fishing sector (low vulnerability). Since fishing intensity is estimated to be low, the value of residual impact is defined as low. Given that the area excluded to fishing is small compared with the total available fishing area and that the area around the Liberator field is already exploited for its oil and gas reserves meaning that fishermen are used to avoiding it, the magnitude of residual impact is estimated to be minor. Sea users other than fisheries relates to shipping, which is of low intensity in the Project area. It is therefore capable of accommodating any short term interference (negligible sensitivity) without changing behaviour (negligible vulnerability), this makes limited use of the Liberator field (negligible value) and only very localised effects are expected (minor magnitude). On this basis, the consequence is low and the impact not significant. Consequence Low Impact Significance Not significant 5.6 Atmospheric Emissions Description and quantification of impact The emission of gases to the atmosphere from the Liberator Phase 1 Field Development could potentially result in impacts at a local, regional, transboundary and global scale. Local, regional and transboundary issues include the potential generation of acid rain from nitrogen and sulphur oxides (NOx and SOx) released from combustion, and the human health impacts of ground level nitrogen dioxide (NO2), sulphur dioxide (SO2), both of which will be released from combustion) and ozone (O3), generated via the action of sunlight on NOx and volatile organic compounds (VOCs). On a global scale, concern with regard to atmospheric emissions is increasingly focused on global climate change. The Intergovernmental Panel on Climate Change (IPCC) in its fourth assessment report states that Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas (GHG) concentrations. Climate change projections included in the IPCC report for Europe and Africa forecast a temperature increase of between 2.3 C and 5.3 C in the period from 2080 to GHGs include water vapour, carbon dioxide (CO2), methane (CH4), nitrous oxides (N2O), O3 and chlorofluorocarbons. The most abundant GHG is water vapour, followed by CO2. IPCC (2007) reports a 35% increase in CO2 concentrations compared to pre-industrial concentrations and states that the combustion of fossil fuels is the primary contributor. 119

120 Atmospheric emissions from the Liberator Phase 1 Field Development during the commissioning phase will be related largely to fuel consumption by the drill rig, installation vessels and helicopters (Section 2.7) and flaring activities if well testing is carried out (Section 2.6.3). During the operational phase emissions will occur primarily due to the increased fuel gas requirement of the Bleo Holm FPSO to process Liberator production. There is not expected to be any additional flaring at Bleo Holm from the Liberator field coming online as the gas will be of export quality. A summary of predicted atmospheric emissions for the Liberator Phase 1 Field Development is provided in Table 5-5. Table 5-5 Atmospheric emissions from the Liberator Phase 1 Field Development (fuel use and emissions factors derived from Institute of Petroleum (2000) and Environmental and Emissions Monitoring System (EEMS, 2008)) Activity Source Details Drilling and completion Subsea installation Emissions (tonnes) CO2 CO NOx N2O SO2 CH4 VOC CO2e 14 Drill rig 138 days 22, ,515 Anchor handling vessel Safety vessel Supply vessel Helicopter use Well testing Survey vessel Survey and light construction vessel Pipelay vessel Pipelay vessel Trenching vessel 17 days days 1, , days 2, , trips for drilling campaign Two well tests not lasting more than 96 hours each Pre-lay survey 4 days Support - 4 days Pipelay 9 days Umbilical lay 6 days Pipeline trenching 6 days , , Carbon dioxide equivalent (CO 2-e ) is a term for describing different greenhouse gases in a common unit. For any quantity and type of greenhouse gas, CO 2-e signifies the amount of CO 2 which would have the equivalent global warming impact. 120

121 Activity Source Details Trenching vessel DSV Rock placement vessel DSV Guard vessel Maintenance Survey Vessel Umbilical trenching 3 days Tie-in 10 days Upheaval buckling mitigation 5 days Lay mattresses and commissioning activities 9 days Emissions (tonnes) CO2 CO NOx N2O SO2 CH4 VOC CO2e days Inspection and maintenance 15 days days 2, , days 5, ,846 Fuel use at Bleo Holm attributable to Liberator days 5, , days 5, , days 5, , days 5, , days 5, ,846 Total 15 83, ,150 Mitigation i3 Energy will take appropriate steps to ensure the following: All vessels will comply with the Merchant Shipping (Prevention of Air Pollution from Ships) (Amendment) Regulations 2014; 15 There may be minor discrepancies between the totals row and the sums of the individual line items due to rounding errors. The totals row captures the emissions from each line item to several decimal points. 121

122 All combustion equipment will be subject to regular monitoring and inspections to ensure an effective maintenance regime is in place, ensuring all combustion equipment runs as efficiently as possible; Operations will be carefully planned to reduce vessel numbers and the duration of operations; All vessels will have the appropriate UK Air Pollution Prevention or International Air Pollution Prevention certificates in place as required; The duration of well testing will be limited as far as is practicable to reduce the requirement to flare; and Operational fuel use and flaring will be managed by the existing permits in place at the Bleo Holm FPSO and in line with existing monitoring and maintenance procedures in place on the facility. Seasonal sensitivities of potential receptors are not considered to be sufficiently variable to mean seasonal mitigation commitments are of value. Cumulative and in-combination impact assessment Local Air Quality Throughout the drilling, installation, commissioning and operation of the Liberator Phase 1 Field Development there will be atmospheric emissions, which may or may not have local or regional (including transboundary) effects. Any releases from drilling, installation and commissioning vessels will be transitory, whilst emissions from operational activities will be intermittent throughout the life of the field. The Liberator field is too remote from other industrial activities (including other offshore oil and gas activity) for there to be any likely cumulative effects in terms of local air quality or health impacts. Whilst there may be an increase in fuel use at the existing Bleo Holm FPSO, the additional potential emissions are sufficiently low that no cumulative impact on local air quality is expected. The drilling activities associated with the Liberator Phase 1 Field Development are sufficiently far from the Scottish coast (64 km) and UK/Norway median line (171 km) that there will be no significant coastal or transboundary impacts Global Climate Change To understand the potential impact from the atmospheric emissions associated with the Liberator Phase 1 Field Development, it is useful to set the emissions in the context of wider UK emissions (and not only in context of emissions in the local area). Whilst, an exact figure for offshore emissions in UK waters does not exist, the contribution of emissions from shipping activities can be summed with oil and gas industry emissions to provide a benchmark against which the Liberator Phase 1 Field Development can be considered. The latest available total annual CO2 emissions estimate from oil and gas exploration and production is 12,585,700 tonnes (for 2014, Oil and Gas UK, 2015) and the latest total annual CO2 emissions estimate for UK shipping is approximately 11,000,000 tonnes (for 2013, DECC, 2015, cited in Committee on Climate Change, 2015a), giving a total of 23,585,700 tonnes of CO2. Emissions from the 122

123 drilling and completion, installation and operation of the Liberator Phase 1 Field Development are estimated to be approximately 83,075 tonnes of CO2, which will contribute approximately 0.39% of the atmospheric emissions associated with UK offshore shipping and oil and gas activities. Whilst this is a very small percentage of current UK offshore emissions, the UK Government has set a target of reducing the UK s overall GHG emissions by 80% by 2050 as part of the Climate Change Act 2008 and a series of phased budgets have been implemented (Table 5-6), with the 5th carbon budget setting a 57% reduction by As such, it is likely that the total annual emissions from the UK will decline over the life of the Liberator Phase 1 Field Development and it is important therefore to examine how the Liberator Phase 1 Field Development will sit within the context of declining UK emissions. Table 5-6 UK Carbon Budget Budget Annual carbon budget % reduction below base year (1990) 1 st carbon budget (2008 to 2012) 3,018 million tonnes (Mt) CO 2 e 23% 2 nd carbon budget (2013 to 2017) 2,782 MtCO 2 e 29% 3 rd carbon budget (2018 to 2022) 2,544 MtCO 2 e 35% by th carbon budget (2023 to 2027) 1,950 MtCO 2 e 50% by th carbon budget (2028 to 2032) 1,765 MtCO 2 e 57% by 2030 Table 5-7 presents Liberator Phase 1 Field Development CO2e emissions against UK carbon budgets. Table 5-7 Liberator Phase 1 Field Development CO2e emissions against UK carbon budget Emission item Carbon accounting period 2018 to to 2027 UK carbon budget for period (tonnes CO 2 e) 2,544,000,000 1,950,000,000 Liberator Phase 1 Field Development emissions for period (tonnes CO 2 e) Liberator Phase 1 Field Development CO 2 e emissions as % of UK budget 79,458 13, <0.001 The large majority of emissions from the Liberator Phase 1 Field Development (approximately 85%) occurs in the 3rd UK carbon budget period from For this carbon budget period, the UK s total carbon budget is 2,544 MT CO2e. The total estimated Liberator Phase 1 Field Development CO2e emissions for this five year period is equal to approximately 0.003% of the whole UK budget, a very small component of the overall emissions in the UK. It should also be noted that, to an extent, the additional CO2 emissions from the Liberator Phase 1 Field Development will be offset by reducing emissions associated with currently declining production in other UK oil and gas fields. 123

124 Overall, this assessment shows that the potential emissions from the Liberator Phase 1 Field Development will likely have a limited cumulative effect in the context of the release of GHGs into the environment and their contribution to global climate change (i.e. the Development will not lead to a significant cumulative or transboundary impact). Transboundary impact assessment The Liberator field is located approximately 171 km from the UK/Norway median line. Due to this distance there are expected to be no significant transboundary impacts as a result of changes in air quality in the Liberator field. The impact assessment presented above for cumulative impact demonstrates that the Liberator Phase 1 Field Development activities will make no significant contribution to UK emissions to the global atmosphere. As such, there will be no significant transboundary impacts. Decommissioning At the end of field life, the Liberator Phase 1 Field Development will be decommissioned. The decommissioning process will generate atmospheric emissions both directly from cessation operations and associated vessel traffic, and indirectly through the reuse and recycling of materials (e.g. steel). It is not possible at this stage to fully quantify the likely atmospheric emissions, and exact emissions will depend on the removal technologies available at that time, as well as the regulatory requirements. It is anticipated that atmospheric emissions are likely to be limited compared to those seen during installation and commissioning activities since the main source of emissions during the commissioning stage is from the drilling rig (Section 5.6.1). Protected sites Atmospheric emissions associated with the Liberator Phase 1 Field Development will not occur within any SAC, SPA, NCMPA or MPA. The atmospheric emissions are expected to represent a very small percentage of UK emissions and there is considered to be no cumulative impact from the Project with regards to the potential impact on protected sites. As such there is considered to be no Likely Significant Effect on SACs and SPAs and hence no impact on conservation objectives or site integrity. This assessment also considers there to be no potential for atmospheric emissions to interact with protected features of an NCMPA or MPA and there is therefore no significant risk to the conservation objectives of any NCMPA or MPA. No impact is expected on the seabed habitat features identified in FEAST. Residual impact Given the temporally restricted nature of the majority of the atmospheric emissions from the Project and taking into account the distance that the Liberator field is from any potentially sensitive receptors, it is not expected that atmospheric emissions will negatively impact local air quality. In terms of global climate change (i.e. cumulative and transboundary impacts), the Liberator Phase 1 Field Development will add a relatively small increment to the overall offshore emissions of the UK and the release of GHG into the environment and their contribution to global warming will be negligible or minor in relation to those from the wider offshore industry and outputs at a national or international level. Any cumulative impact is therefore considered not to have a direct impact on climate change. 124

125 Considering all of the above, including that there will be no impact on protected sites or on species from protected sites, the residual consequence of atmospheric emissions is ranked as negligible. As the majority of emissions will occur during the drilling and installation phases and the only operational emissions will be the limited flaring and maintenance activities, the frequency is defined as infrequent. As a result the residual risk of atmospheric emissions from the Liberator Phase 1 Field Development will be negligible and is therefore not significant. Receptor Sensitivity Vulnerability Value Magnitude Atmosphere Low Low Low Minor Rationale The information in the Environment Description (Section 3) has been used to assign the sensitivity, vulnerability and value of the receptor as follows. On the basis that the atmosphere has the capacity to accept the emissions without change, the receptor sensitivity is ranked as Low. As the sensitivity is ranked as low and the magnitude is ranked as minor, vulnerability is considered to be low. A ranking of low has been assigned to the value of the receptor as there are no air quality issues identified in the vicinity and the impact will only impact on a small area of the atmosphere in the immediate vicinity of the Liberator field. In a global climate context, the anticipated emissions from the Project activities are limited. Considering this, including that effects unlikely to be discernible or measurable, the magnitude of impact is ranked as minor. On this basis, the consequence is negligible and the impact not significant. Consequence Negligible Impact significance Not significant 5.7 Accidental Events Introduction Description and quantification of impact The potential impact of any accidental hydrocarbon and chemical release will be determined by the characteristics of the release of hydrocarbons or chemicals, its weathering properties, the direction of travel and whether environmental sensitivities lie in its path. These environmental sensitivities will have spatial and temporal variations. Therefore, the likelihood of any accidental release having a potential impact on the environment must consider the likelihood of the release occurring against the probability of that hydrocarbon or chemical reaching a sensitive area and the environmental sensitivities present in that area at the time of hydrocarbon or chemical release Sources and likelihood of occurrence Blowout and well releases Primary well control is the process which maintains a hydrostatic pressure in the wellbore greater than the pressure of the hydrocarbons in the formation being drilled via a drilling fluid/mud. If the formation pressure is greater than the hydrostatic pressure of the drilling fluid in the wellbore the well will flow and the hydrocarbons will enter into the wellbore. If the primary well control fails this flow may be stopped by closing the BOP, which is the initial stage of secondary well control. Secondary well control is completed by circulating out the 125

126 hydrocarbons and displacing the wellbore to the new kill weight drilling fluid / mud. If primary and secondary well control fail, a blowout may occur. A surface blowout is defined as an uncontrolled flow of formation hydrocarbons from the reservoir to the surface which occurs as a result of loss of primary (hydrostatic pressure) and secondary (BOP) well control, and may lead to the potential for release of hydrocarbons to the environment. An underground blowout is when downhole pressure exceeds the fracture pressure of a formation and hydrocarbons flow into the weaker formation. A well release is defined as formation hydrocarbons flowing from the well when flow was not intended, but only when flow was subsequently stopped by use of the barrier system that was available on the well at the time that the incident started as such, the quantities of hydrocarbons released during a well release are usually much smaller than during a blowout. The proposed Liberator wells will be drilled from a semi-submersible drill rig. Whilst historical data for frequency of blowouts from drill rigs on the UKCS between 1990 and 2007 (Table B 1, Appendix B) do not provide information on the severity of the event or whether the blowout or well leak led to an oil accidental release, they do provide an indication of overall frequency of blowouts in the UKCS. Between 1990 and 2007, blowout frequency was incidents per year. Blowouts are extremely rare events in modern drilling (Oil & Gas UK, OGUK, 2009; Table B 2, Appendix B); whilst over 6,000 development wells drilled on the UKCS between 1980 and 2010 (UKOOA, 2010), International Association of Oil & Gas Producers (IOGP, 2010) report that only 34 development drilling blowouts were recorded over the same period (and those blowouts also included a number in the Norwegian sector of the North Sea). Based on IOGP (2010) analysis (detailed in Table B 3 in Appendix B) and on the probability definitions in Table 4.8 in Section 4, the likelihood of a blowout is considered remote, and a well release is considered unlikely. Nevertheless, as the consequence of a hydrocarbon release of any nature is potentially significant, i3 Energy will implement rigorous measures to reduce the potential for a failure of well control and ensure effective response should an incident occur (these are detailed in Section 5.7.2). Drill rig accidental releases The proposed wells will be drilled from a semi-submersible drill rig. Potential accidental releases from drill rigs may be caused by mechanical failure, operational failure or human error, and release sources include drilling muds, oil and chemicals and hydraulic fluids. During the period 2001 to 2007, 172 years of operational activity were logged by drill rigs on the UKCS with no accidental releases greater than 100 tonnes recorded. The majority of accidental releases recorded were less than 1 tonne (Table B 4, Appendix B). The most common types of accidental release from drill rigs were found to be associated with drilling (42%); 94% of which were less than 1 tonne. The second most common type of release was from maintenance/operational activities (27%), with 97% of these less than 1 tonne. In addition to accidental releases generally being small volumes, the number and frequency of accidental releases has declined in recent years (Table B 5, Appendix B). 126

127 Other than blowouts, the types of credible accidental loss scenarios associated with the drill rig which could result in the greatest environmental impact could be collision, explosion or vessel grounding (although the latter is unlikely to be associated with the Liberator Phase 1 Field Development), which could result in a total loss of hydrocarbon inventory. The largest fuel inventories will be associated with the drill rig, although it is unlikely that the maximum storage capacity of marine diesel would be maintained for any extended period. In terms of collision with drill rigs, available data indicate a reduction in the frequency of such incidents between 1990 and 2007 (Table B 6, Appendix B). Subsea tie-backs Of all accidental releases reported from subsea tie-back facilities between 1975 and 2007, the majority (over 70%) were less than 1 tonne (TINA Consultants Ltd pers. comm., 2013) (detailed in Appendix B). Pipelay and other support vessel accidental releases Potential sources of accidental releases from pipelay and support vessel operations include: Upsets in bilge treatment systems; Storage tank failure of lube oils, fuel oil (diesel), oil-based mud, base oil and chemicals; Accidental release during maintenance activities including equipment removal and lubrication; Refuelling and cargo loading operations in port; and Damage sustained during a collision, grounding or fire. The most frequently reported accidental releases from vessels are associated with upsets in bilge treatment systems and are usually small (<1 tonne). The most recent Advisory Committee on Protection of the Sea (ACOPS) report on discharges to sea states that in 2014, approximately 73% of accidental chemical releases involved PLONOR chemicals, which are considered to pose little or no risk to the environment (ACOPS, 2015). No chemicals that are included in the OSPAR list of chemicals for priority action (i.e. those which are considered to pose the greatest potential impact) were released and none of the releases were recorded as having resulted in a significant environmental impact Behaviour of hydrocarbons at sea The potential environmental impact of an accidental hydrocarbon release depends on a wide variety of factors, which include: Release volume; Type of hydrocarbon released; Direction of travel of the release; Weathering properties of the hydrocarbon; 127

128 Any environmental sensitivities present in the path of the release (these may change with time); and Sensitivity of the impacted locations. The Oil Spill Contingency and Response (OSCAR) model has been developed by Sintef to model the fate of accidentally released hydrocarbons at sea. It has a built-in oil database, containing over 110 oils, along with various gridded wind and current files, originally produced by the Norwegian Met Office. OSCAR is a three-dimensional model, designed to predict the fate of oil particles at the surface, sub-surface and once dissolved. OSCAR calculates and records the distribution in three physical dimensions, plus time, of a contaminant on the water surface, along shorelines, in the water column, and in the sediments. The model is capable of undertaking both stochastic and deterministic modelling: The stochastic mode is used to estimate the likelihood of particular trajectories occurring, based on historical wind speed and direction data. Stochastic models, often called probability models, show the probability of where an oil spill may migrate from the spill source under different environmental conditions. The model computes a series of trajectories under various wind and current conditions from the historic wind records and current records. These results are combined a probability density map of the spatial likelihood of oil occurrence; and The deterministic mode is used to predict the route of a hydrocarbon slick over time, and to estimate the oil weathering profile, under specific meteorological conditions. Modelling outputs include the trajectory of the slick and mass balance estimates over time (i.e. the slick volume and how much oil is estimated to have dispersed, emulsified or evaporated). In essence, deterministic modelling investigates whether or not, and how quickly, oil might beach under a constant (typically worst-case) wind speed and direction. Seasonal (winter December to February, spring March to May, summer June to August and autumn September to November) stochastic modelling using OSCAR was undertaken in line with the latest Oil Pollution Emergency Plans (OPEP) guidance (DECC, 2015). A minimum of 100 runs were performed for each season, with the historical meteorological data used to inform the model spanning a period of 7 years from The accidental release scenarios modelled for the Project are detailed in Table 5-8. In line with current regulatory and industry commentary and experience with worst-case scenario identification, the following assumptions have been made whilst undertaking the modelling for the Liberator Phase 1 Field Development: Interactions: all scenarios are run with the assumption that there is no response from any party, operator, local or national government. This approach is taken in order to view the worst-case predictions of a spill and should be used as guidance only to build and define oil spill contingency and response plans; and Timeframes: all modelled runs were given 10 days following cessation of release. 128

129 In order to set limits for when the spilled hydrocarbon can be considered insignificant in the environment, the following thresholds have been used: A minimum surface oil thickness threshold of 0.3 μm has been used for all modelled scenarios in line with BEIS guidance; and No such threshold was applied for shoreline oiling. No modelling of diesel release from the FPSO or drill rig has been conducted. The estimated combined total diesel inventory of the drill rig (1,178 m 3 ) and of the Bleo Holm FPSO (3,121 m 3 ) comprises a much smaller volume of hydrocarbons than that associated with well blowout (30,341 m 3 ). Diesel is much more volatile than the crude oil expected from Liberator, and in the event of a diesel inventory spill, the majority of the diesel would be expected to evaporate within a few days, before reaching any sensitive coastlines. Diesel has a lower specific gravity than crude oil, and would be expected to float on the sea surface, meaning there would be no interactions expected with seabed habitats, and the hydrocarbons would be constantly exposed to weathering and evaporation. The only potential impact of a diesel release in the Liberator field is likely be on seabirds located relatively close to the Project location, and any impacts that did occur would be much reduced compared to those associated with crude oil from a well blowout on the same receptors. The well blowout scenario is therefore considered to be the worst case, and it is not envisaged that any potential impacts will be overlooked through omission of diesel release modelling. Table 5-8 Summary of accidental release scenarios modelled for the Project Scenario No. Scenario description 1 Well blowout at Liberator L1 well using the highest unconstrained well flow rate for 84 days Hydrocarbon type Release volume Crude oil 30,341 m 3 oil over 84 days (variable flowrate) Modelled depth of release Surface, followed by subsea Model type Stochastic Scenario 1: Well blowout at L1 The surface probability of contamination is presented in Figure 5-1. Surface minimum arrival time of released hydrocarbon is illustrated in Figure 5-2. The minimum crossing times to all relevant median lines are shown in Table 5-9. Modelling indicated that there was a probability of % of oil crossing the UK/Norway transboundary line within five days of release (or three days in winter). The probability of oil crossing any other transboundary lines was less than 30%. 129

130 Table 5-9 Shortest time to reach and probability ( 1%) of surface oil ( 0.3 μm) crossing median line Shortest time to reach and probability ( 1%) of surface oil ( 0.3 μm) crossing median line Median line Dec Feb Mar May Jun Aug Sep Nov Norway 3 days 5 days 5 days 5 days Denmark 13 days >20 days >20 days >20 days Sweden >20 days >20 days >20 days >20 days Germany >20 days >20 days >20 days >20 days Netherlands >20 days - >20 days Faroes - >20 days

131 Probability of Surface Oiling Meeting or Exceeding 0.3 μm Dec - Feb Mar - May Jun - Aug Figure 5-1 Sep - Nov Scenario 1 well blowout: surface probability of contamination (above 0.3 μm thick) 131

132 Arrival Time of Surface Oil Dec - Feb Mar - May Jun - Aug Figure 5-2 Sep - Nov Scenario 1 well blowout: surface arrival time (above 0.3 μm thick) The shortest arrival time for oil beaching on North Sea coastlines in each season is presented in Table The probability of shoreline oiling is generally less than 30% for most areas; the areas at most risk are expected to be Grampian (up to 70% probability within 2 days) and Orkney (up to 40% probability within 2.5 days). 132