Deep Panuke Offshore Gas Development. Comprehensive Study Report

Transcription

1 Deep Panuke Offshore Gas Development Comprehensive Study Report October 2002

2 DEEP PANUKE OFFSHORE GAS DEVELOPMENT COMPREHENSIVE STUDY REPORT Prepared By: EnCana Energy Corporation 7 th Floor, Royal Centre 5161 George Street Halifax, Nova Scotia B3J 1M7 Prepared for: Canada-Nova Scotia Offshore Petroleum Board 6 th Floor, TD Centre 1791 Barrington Street Halifax, NS B3J 3K9 October 2002

3 EXECUTIVE SUMMARY EnCana Corporation (EnCana) proposes to develop the Deep Panuke Offshore Gas Development Project (the Project). The Project is intended to develop a significant natural gas reservoir located offshore on the Scotian Shelf, approximately 175 km southeast of Goldboro, Nova Scotia (NS), and 250 km southeast of Halifax. The Project will enable EnCana to exercise its rights under, and obtain economic benefit from, the licences issued to it under the Canada-Nova Scotia Offshore Petroleum Resources Accord Implementation Act and Canada-Nova Scotia Offshore Petroleum Resources Accord Implementation (Nova Scotia) Act. The proximity of the Deep Panuke discovery to existing infrastructure serving growing energy markets in Canada and the United States is one of the foundations of the Project. This document is the Comprehensive Study Report (CSR) required for this Project under the Canadian Environmental Assessment Act (CEAA). The Responsible Authorities (RAs) for this Project include: the Canada-Nova Scotia Offshore Petroleum Board (CNSOPB) (lead RA); the National Energy Board; Fisheries and Oceans Canada; Industry Canada; and Environment Canada. The preparation of the CSR was delegated to EnCana pursuant to Section 17 of the CEAA. The CSR has been prepared to meet the environmental assessment requirements under the CEAA and the scope of the assessment prepared for the Project under a Memorandum of Understanding (MOU) between the RAs, the Canadian Environmental Assessment Agency (CEA Agency) and the Province of Nova Scotia. The CSR is based on a series of documents filed in an application with the CNSOPB referred to collectively as the Development Plan Application (DPA). The DPA, while not critical to reading and understanding the CSR, contains additional detail that may interest some readers. The DPA comprises six volumes, as follows: Project Summary (DPA Volume 1); Development Plan (DPA Volume 2); Canada-Nova Scotia Benefits Plan (DPA Volume 3); Environmental Impact Statement (EIS) (DPA Volume 4); Socio-Economic Impact Statement (SEIS) (DPA Volume 5); and Public Consultation Report (PCR) (DPA Volume 6). In accordance with the MOU and scope of the environmental assessment, EnCana submitted a draft CSR, in addition to the DPA documents, to the signatory parties and the public for review and comment. The CNSOPB, as lead RA, coordinated comments from the RAs and Expert Federal Authorities, as well as comments from the public. The Nova Scotia Department of Environment and Labour (NSDEL) ES-i

4 coordinated provincial comments and provided them to the CNSOPB. These comments were forwarded to EnCana for consideration in the preparation of a revised CSR. A response document (Addendum 1) was prepared to respond specifically to these comments and was filed with the CNSOPB in September 2002 as a supporting document to the DPA. The CSR has been revised in consideration of these comments. This CSR is based on the analysis presented in the EIS (DPA Volume 4) and SEIS (DPA Volume 5) and updated as necessary to reflect Project updates and comments received during the review of the DPA and draft CSR. Current Project design consists of three bottom-founded platforms in a water depth of approximately 40 m. The wellhead platform will be dedicated to dry wellheads, the wellhead control system, and production manifolds. The production platform will contain all power generation and processing equipment; this equipment is designed to process 400 MMscfd of natural gas at peak production with turndown capabilities as the Deep Panuke field declines. A third platform, the accommodations (utility/quarters) platform, will contain utilities, a helicopter landing pad, refueling station and crew accommodations. The three platforms will be interconnected by pedestrian/service bridges. The gas processing system will consist of equipment necessary for separation, measurement, dehydration, and hydrocarbon dew point control. Deep Panuke is considered to be a sour gas reserve with raw gas containing approximately 0.2% hydrogen sulphide (H 2 S). Gas sweetening equipment will, therefore, also be required. Full gas processing will be conducted offshore through application of an amine unit to remove H 2 S and carbon dioxide (CO 2 ) (acid gas). The acid gas will be injected under compression to a dedicated disposal well in an approved geological formation. Condensate produced during offshore processing will be consumed on the production platform as the primary fuel; any surplus condensate will be injected into a disposal well. Market-ready gas will be produced offshore and transported via subsea pipeline to Goldboro, Nova Scotia to an interconnection with the Maritimes & Northeast Pipeline (M&NP) main transmission pipeline for transport to markets in Canada and the Northeast United States. EnCana s onshore facilities will consist of the physical components necessary for interconnection of EnCana s natural gas pipeline with M&NP facilities. The production life of the Project is anticipated to be 11.5 years, with a design life of 25 years. A description of the Project including reservoir description, Project components, Project activities and schedule are presented in Section 2. Alternatives to the described Project, and alternative means of carrying out the Project, are presented in Section The capital cost of Project construction is estimated to be $1.1 billion. The annual operating cost of the Project is estimated to be $60 million, of which just over $31 million will be material purchasing. Project development is anticipated to involve 2,805 person years of work (approximately 3,787 short term jobs of which 40% are estimated to accrue to Nova Scotians). The production phase is estimated to generate an average of 3,159 person years of employment over the life of the Project (approximately 312 ES-ii

5 jobs, 91% of which are estimated to accrue to Nova Scotians). Regional and local economic benefits are presented in Section 7.2. It is anticipated that the proposed Project will produce minor routine emissions and discharges typical of other oil and gas projects currently proposed and/or operating in the Canadian offshore including: air emissions from power generation and routine flaring; drilling waste; produced water; deck drainage; sewage; noise; and light. EnCana will strive to reduce all wastes and discharges in order to promote efficient operation. EnCana will ensure compliance with all applicable regulations and company standards for discharge limits including those specified in the Offshore Waste Treatment Guidelines (NEB et al. 1996, and updates). Routine Project emissions and discharges are described in Section 2.7, with atmospheric emissions and produced water dispersion modeling results presented in Appendix C. EnCana has reviewed the various potential malfunctions and accidental events that may occur during the Project including platform spills, malfunction of the acid gas management system, blowouts and pipeline ruptures. Spill risk has been modeled to determine the probability and extent of such events. EnCana has incorporated design features and procedures to virtually eliminate or minimize the risk of major releases. EnCana will also develop and implement safety, spill response and contingency plans to reduce adverse environmental effects in the unlikely event of such incidents. Potential accidents and malfunctions, spill risk and probability, and spill release behavior are presented in Section 3. Emergency response and contingency planning commitments are described in Section 4 and Appendix D. The biophysical impact assessment (Section 6) focuses on environmental issues of greatest concern, known as Valued Environmental Components (VECs). An issues scoping process was undertaken to identify VECs most appropriate for this assessment. This scoping included: stakeholder consultation; regulatory issues and guidelines; research; and professional judgement of the Study Team. As a key component of Project planning and assessment, EnCana has conducted an extensive program of public consultation with stakeholder groups, and discussions with First Nations and Aboriginal groups. This program and ongoing initiatives are summarized in Section 5. The objectives of this program are to: provide information about the Project in a timely fashion; provide opportunities for identification of issues and concerns; seek technical advice; and develop mutually beneficial relationships throughout the life of the Project. The public consultation program focused on key stakeholder groups including: regulatory agencies; local municipalities and regional development authorities; nearshore fishing interests; offshore fishing interests; residents and businesses in the Guysborough County area; scientists; environmental non-governmental organizations; and the general public. Dialogue with several First Nations and Aboriginal organizations has also been initiated to determine Project related issues and concerns among their members. Issues and concerns identified ES-iii

6 through the consultation and discussion process have been considered in Project planning, design and the impact assessment. The following VECs were selected for the assessment: Air Quality; Marine Water Quality; Marine Benthos; Marine Fish; Marine Mammals (Whales and Seals); Marine Related Birds Sable Island; and Onshore Environment. Impact assessment methodology including issues scoping and VEC selection rationale is described in Section 6.2. Potential Project interactions, assessment boundaries, evaluation criteria, impact analysis, mitigative measures and proposed monitoring are presented for each VEC in Section 6.3. EnCana is committed to a high level of environmental protection through Project design and mitigation measures. Some of these key voluntary environmental management features proposed for the Project include: injection of waste acid gas into a secure geological formation to greatly reduce potential atmospheric emissions of greenhouse ga ses and sulphur compounds; a target for dispersed oil in produced water discharges lower than regulatory requirements; no marine discharge of non-aqueous drill muds and associated cuttings; energy conservation measures including waste heat recovery and use of produced condensate for offshore power generation; the use of an existing offshore pipeline corridor; a pipeline designed to minimize interference with fishing activity; no nearshore pipeline construction during the lobster fishing season (April 19 to June 20) which also covers the period when the endangered Roseate Tern typically prospects for nests and lays eggs on nearby Country Island (May 1 June 20); routing of the onshore portion of pipeline to avoid sensitive areas such as wetlands and major stream crossings; and implementing codes of practice for environmentally sensitive areas - Sable Island, Country Island and the Gully. ES-iv

7 Table 9.1 in Section 9 summarizes commitments made by EnCana in its DPA and CSR to ensure there will be no significant adverse residual environmental effects as a result of the Deep Panuke Project. EnCana will also implement several environmental management documents such as: Environmental Management Plan; Environmental Protection Plans; Environmental Effects Monitoring Plan; Waste Management Plan; Chemical Management Plan; Spill Response Plan; Alert/Emergency Response Contingency Plan; Fisheries Compensation Plan; and Decommissioning Plan. In general, any potential adverse environmental effects from routine Project activities will be short-term, highly localized, and/or of low magnitude. Non-significant adverse effects include: impacts on air quality from routine air emissions; impacts on water quality from routine effluents; temporary disturbance to benthic habitat from WBM drill waste discharges and pipeline installation; and minor habitat loss and disturbance associated with installation of the onshore pipeline and facilities. These effects can be effectively mitigated to non-significant levels through the application of technically and economically feasible measures, standard offshore oil and gas industry procedures, and adherence to regulatory guidelines. Section 4 and Appendix D contain information on EnCana s environmental management framework and outlines for environmental plans. Appendix E contains environmental codes of practice adopted by EnCana for Sable Island, the Gully, and Country Island. The effects from routine Project construction, operation and decommissioning activities are therefore predicted to be not significant for all VECs. In the unlikely event of a well blowout or piping break resulting in the release of large amounts of raw gas or acid gas, significant adverse effects on air quality may occur. Such an event could have health and safety consequences for platform workers and passengers on vessels downwind. Design prevention measures, rendering such an event extremely unlikely, and emergency response contingency planning, will further reduce the likelihood that workers or others would be seriously affected by emissions. In general, spill modeling indicates that accidental releases of hydrocarbon from the Project will dissipate quickly without widespread effects; for example, a spill from a blowout would not reach Sable Island. The socio-economic impact assessment focuses on socio-economic issues of greatest concern: the economy; environment; infrastructure; and social factors. These issues are considered for each of the potentially affected geographical areas, including: the Halifax Regional Municipality (HRM); service and landfall communities; and the offshore area. Mitigation is proposed where appropriate, to reduce potential adverse socio-economic effects. ES-v

8 The proposed Project will bring significant benefits to the economy of Nova Scotia, specifically 3,220 direct and indirect jobs and a $154 million contribution to household income during development. The Project will also bring considerable socio-economic benefits to HRM. It is not considered likely that the Project will cause significant adverse socio-economic effects, provided proposed mitigation measures noted in this report are implemented. To enhance the benefits that may accrue, particularly to the landfall areas and service communities, EnCana will establish a procedure to notify the municipalities, Chambers of Commerce and appropriate regional development authorities, prior to and during the construction period, of the products and services that are required. Effects of the environment on the Project are not considered to be significant. Project facilities will be designed and installed based on the appropriate environmental design criteria to ensure the safety and the integrity of these facilities during severe environmental conditions. Monitoring and/or contingency planning will also serve to minimize any adverse effects. In conclusion, the Deep Panuke Project is not likely to cause significant adverse environmental effects. The Project will contribute to the development of the offshore oil and gas industry in Atlantic Canada by establishing a viable facility and operation that will reduce adverse environmental effects to acceptable levels through the use of technically and economically feasible design and mitigation measures. ES-vi

9 TABLE OF CONTENTS Page No. EXECUTIVE SUMMARY...ES-i 1 INTRODUCTION Project Overview Purpose and Need for the Project Regulatory and Planning Context Scope of the Assessment Project Study Area PROJECT DESCRIPTION Reservoir Description Project Infrastructure Components Offshore Platforms Subsea Equipment Offshore Pipeline Onshore Pipeline and Facilities Construction and Installation Offshore Production Facilities Subsea Pipeline Onshore Facilities and Pipeline Development Well Construction Operations Production Support and Servicing Project Safety Zones Onshore Facilities Decommissioning and Abandonment Project Schedule Emissions and Discharges Air Emissions Noise Emissions Electromagnetic Emissions TOC-i

10 2.7.4 Drill Waste Discharges Effluent Discharges Naturally Occuring Radioactive Material (NORM) Non-Hazardous Solid Wastes Hazardous Materials and Waste Environmental and Safety Protection Systems Equipment Inspection and Maintenance Pipeline Leak Prevention Blowout Prevention Safeguards Project Alternatives Alternatives to the Project Alternative Means of Carrying Out the Project MALFUNCTIONS AND ACCIDENTAL EVENTS Potential Malfunctions and Accident Events Platform-based Spills Collisions Malfunction of Acid Gas Management System Blowout Releases Pipeline Releases Effects of the Environment on the Project Marine Spill Risk and Probability Platform-based Spills Blowouts Onshore Pipeline Risk Accident Scenarios Hazards Risks Subsea Pipeline Risk Deep Panuke Risk Exposure General Comparison of Gas and Oil Pipeline Accident Frequencies Prediction for Deep Panuke Marine Spill Release Behaviour Platform-based Spills Blowouts TOC-2

11 4 HEALTH, SAFETY AND ENVIRONMENTAL MANAGEMENT Health, Safety and Environment Corporate Statement Operations Risk Management System Environment, Health and Safety (EHS) Management System Stakeholder Consultation Programs PUBLIC CONSULTATION PROGRAM Consultation Program Objectives Consultation Activities Public Consultation Phases Phase I - Preliminary Stakeholder Communications Phase II Consultation on the Project Description and Issues Scoping Phase III Consultation on Project Revisions and Environmental Assessment Phase IV - Ongoing Communication Aboriginal Communications Phase I Preliminary Communications Phase II Communication on the Project Description and Issues Scoping Phase III Project Revisions and Environmental Assessment Phase IV Ongoing Communications Integration of Issues and Concerns into Project Planning Integration into Project Planning BIOPHYSICAL ASSESSMENT Ecological Setting Marine Physical Environment Marine Biological Environment Onshore Environment Summary of Special Status Species Impact Assessment Methodology Issues Scoping and Selection of Valued Environmental Components Potential Interactions Between Project Activities and Valued Environmental Components Environmental Effects Assessment Framework Cumulative Effects Assessment Follow-Up and Monitoring Sustainable Use of Renewable Resources TOC-3

12 6.2.7 Summary of Residual Environmental Effects Assessment Biophysical Impact Assessment Air Quality Marine Water Quality Marine Benthos Marine Fish Marine Mammals (Seals and Whales) Marine Related Birds Sable Island Onshore Environment Cumulative Effects Summary SOCIOECONOMIC ASSESSMENT Approach and Methodologies Socio-economic Context Provincial Profile Halifax Regional Municipality (HRM) Guysborough County Landfall Communities Service Communities The Offshore Socio-economic Impact Assessment National and Provincial: Benefits and Impacts Halifax Regional Municipality: Benefits and Impacts Service Communities: Guysborough, Sherbrooke and Antigonish: Benefits and Impacts Guysborough County and Landfall Communities: Benefits and Impacts The Offshore Area: Benefits and Impacts Cumulative Effects Summary Cumulative Impacts in HRM Cumulative Impacts in Service Communities Cumulative Impacts at Landfall Cumulative Socio-Economic Impacts Offshore Summary of Socio-Economic Cumulative Benefits and Impacts EFFECTS OF THE ENVIRONMENT ON THE PROJECT Climate Change TOC-4

13 8.2 Icebergs and Sea Ice Impacts Superstructure Icing Extreme Water Levels Tsunamis Seismicity Sediment Transport and Seabed Stability Biofouling Summary SUMMARY AND CONCLUSIONS REFERENCES CITED Literature Cited Personal Communications GLOSSARY... Glossary-1 LIST OF TABLES Table 1.1 Document Concordance with Scope of the Environmental Assessment (CNSOPB et al. 2001b) Table 2.1 Typical Composition of Drilling Muds for Deep Panuke Table 2.2 Acid Gas Injection System Composition and Flow Table 2.3 Produced Water Chemistry from Musquodoboit Drill Stem Test Table 2.4 Produced Water Production Rates Table 2.5 Surplus Condensate Table 2.6 Routine Project Emissions/Effluents Table 2.7 Natural and Development Related Underwater Noise Levels Table 2.8 Typical Construction Equipment Noise Table 2.9 Deep Panuke Potential Drilling Waste Discharge Summary Table 2.10 Substructure Development Alternatives Table 2.11 Topside Development Alternatives Table 2.12 Total Number of Platforms Development Alternatives Table 2.13 Re-Use of Existing Platform Development Alternatives TOC-5

14 Table 2.14 Location of Processing Development Alternatives Table 2.15 Acid Gas Handling Development Alternatives Table 2.16 Produced Water Disposal Alternatives Table 2.17 Condensate Handling Alternatives Table 2.18 SBM/EMOBM Cuttings Disposal Alternatives Table 3.1 Reported Spill Volumes from Nova Scotia Offshore Oil and Gas Industry Offshore Nova Scotia ( ) Table 3.2 Predicted Number of Blowouts and Spills for the Deep Panuke Project Table 5.1 Stakeholders Contacted During Phase I Table 5.2 Integration of Key Issues Overview Table 6.1 Sediment Chemistry at the Deep Panuke Well Site Table 6.2 Benthic Macroinvertebrates Observed Within the Cohasset Project Fields and at the Deep Panuke Well Site Table 6.3 Species Observed Along the Nearshore Pipeline Corridor Table 6.4 Life Stages of Fish Species Occurring in the Study Area Table 6.5 Cetaceans Observed on the Scotian Shelf (estimated mean numbers per 100 km 2 ) Table 6.6 Temporal Distribution of Seabirds Likely to be Found Offshore within the Study Area Table 6.7 Species of Special Status that May Occur in the Study Area Table 6.8 Selection of Valued Environmental Components Table 6.9 Definition and Scope of the VECs Table 6.10 Summary of Potential Interactions Between Project Activities and VECs Table 6.11 Nova Scotia Air Quality Regulations (Environment Act) and Canadian Environmental Protection Act Ambient Air Quality Objectives Table 6.12 Typical Air Emissions for Construction and Operation Equipment Table 6.13 Summary of Air Emissions During Project Operation (Normal and Upset Conditions) Table 6.14 Atmospheric Effects from Normal Production (Acid Gas Injection) Table 6.15 Atmospheric Effects from Equipment Maintenance and Upset of Acid Gas System (Acid Gas Flaring) Table 6.16 Nova Scotia GHG Emissions (1997) by Sector Table 6.17 Upset Conditions Acid Gas Flaring H 2 S TOC-6

15 Table 6.18 Upset Conditions Acid Gas Flaring SO Table 6.19 Upset Condition Acid Gas Venting CH Table 6.20 Upset Condition Acid Gas Venting H2S Table 6.21 Acid Gas Injection Well Blowout (Production Phase) H2S Table 6.22 Production Well - Subsea Blowouts Raw Gas CH Table 6.23 Production Well - Subsea Blowout Raw Gas H2S Table 6.24 Production Well - Surface Blowout Raw Gas - CH Table 6.25 Production Well - Surface Blowout Raw Gas - H2S Table 6.26 Residual Environmental Effects Assessment Matrix: Air Quality Table 6.27 Residual Environmental Effects Summary: Air Quality (All phases) Table 6.28 Residual Environmental Effects Assessment Matrix: Marine Water Quality Table 6.29 Residual Environmental Effects Summary: Marine Water Quality (All phases) Table 6.30 Residual Environmental Effects Assessment Matrix: Marine Benthos Table 6.31 Residual Environmental Effects Summary: Marine Benthos (All phases) Table 6.32 Residual Environmental Effects Assessment Matrix: Marine Fish Table 6.33 Residual Environmental Effects Summary: Marine Fish (All phases) Table 6.34 Residual Environmental Effects Assessment Matrix: Marine Mammals Table 6.35 Residual Environmental Effects Summary: Marine Mammals (All phases) Table 6.36 Residual Environmental Effects Assessment Matrix: Marine Related Birds Table 6.37 Residual Environmental Effects Summary: Marine Related Birds (All phases) Table 6.38 Residual Environmental Effects Assessment Matrix: Sable Island Table 6.39 Residual Environmental Effects Summary: Sable Island (All phases) Table 6.40 Residual Environmental Effects Assessment Matrix: Onshore Environment Table 6.41 Residual Environmental Effects Summary: Onshore Environment (All phases) Table 7.1 Project Linkages to Impacts Table 7.2 Aboriginal People in Nova Scotia and Guysborough County Table 7.3 Numbers of Fishermen by Port, Table 7.4 Development Phase Cost Summary by Component Table 7.5 Halifax Regional Municipality: Residual Impacts Table 7.6 Service Communities: Guysborough, Sherbrooke and Antigonish: Residual Impacts Table 7.7 Guysborough County / Landfall Communities: Residual Impacts TOC-7

16 Table 7.8 Table 9.1 Offshore: Residual Impacts Deep Panuke Project Summary of Commitments LIST OF FIGURES Figure 1.1 Project Location Map Figure 2.1 Generalized Stratigraphy of the Scotian Shelf Figure 2.2 Proposed Project Components Figure 2.3 Proposed Offshore Pipeline Route Figure 2.4 Proposed Offshore Pipeline Route (Detail #1) Figure 2.5 Proposed Offshore Pipeline Route (Detail #2) Figure 2.6 Onshore Pipeline Corridor Figure 2.7 Plot Plan for Typical Onshore Facilities Figure 2.8 Typical Production Well Schematic Figure 2.9 Typical Acid Gas Injection Well Schematic Figure 2.10 Simplified Process Flow Diagram Figure 4.1 Deep Panuke Environmental Management Framework Figure 6.1 Past, Present and Existing Offshore Project and Exploration Wells Relative to Deep Panuke Project Area Figure 6.2 Generation of Marine Sounds and Reception of Sound by Animals in the Ocean Environment Figure 7.1 Socio-economic Assessment Methodology Figure 7.2 Average Catch per NAFO Unit Area LIST OF APPENDICES Appendix A Appendix B Appendix C Appendix D Appendix E Appendix F Memorandum Of Understanding On Environmental Assessment Process For The Deep Panuke Project Scope Of The Environmental Assessment For The Proposed Pancanadian Energy Corporation (PanCanadian) Deep Panuke Gas Development Project December 18, 2001 (Revised February 15, 2002) Dispersion Modeling Information On Encana s Proposed Environmental Management Documents EnCana Codes of Practice for Sable Gully, Sable Island, and Country Island Water Quality Data TOC-8