BISSO MARINE ADVANCED BURIAL & BACKFILL PLOUGH

Transcription

1 BISSO MARINE APR 2016

2 PIPELINE PLOUGH BURIAL & BACKFILL Throughout most US Territorial Waters, US Federal and State Governmental regulations require marine, offshore and subsea pipelines to be buried. This requirement exists to assure protection of in situ pipelines from external sources of damage from trawling boards, commercial fishing gear, anchors and contact with vessels etc. Pipeline burial provides on bottom stability protection which further mitigates environmental and/or safety risks generated from the effects of hydrodynamic factors including tides, waves and currents resulting in scouring, resonation, vertical and/or horizontal movement of pipelines which are simply laid on the seafloor. Other than for the safety and security of on bottom stability, the burial of marine, offshore and subsea pipelines can also provide thermal resistance related to reductions of hydrates in natural gas pipelines and paraffin wax deposits in oil pipelines. The burial of pipelines also mitigates risks associated with free span vortex induced vibrations. The BISSO MARINE Advanced Burial Plough can either Pre-Trench a trench in which a pipeline can be laid, or the plough can be placed on top of a previously laid pipeline; then pulled by a DP vessel or a moored barge, to Post- Trench the pipeline. Once a pipeline is in the trench, the burial plough is converted to backfill mode and then pulled over the pipeline which then directs the mound of trenched spoil, back into the trench to cover the pipeline. US Waters Burial Depth Standards for pipelines: Standard Gulf of Mexico Depth of cover 3 feet to top of pipe Standard Northeast US Depth of cover 4 feet to top of pipe Effects Of Burial Methods On The Marine Ecosystems: Turbidity Cloudiness or haziness of a fluid caused by a large volume of particulate that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality. Ploughing Minimal turbidity* Conventional Dredging & Rock or Soil Dumping Moderate Turbidity* Jetting & Pumping Significant Turbidity* *The seafloor s particulate size and weight are the determining factor of the concentration level of turbidity Turbidity primarily impacts marine flora and fauna in the following Oceanic Zones: Pelagic Creatures living in the open ocean in water column Benthopelagic Creatures living above seafloor near the sea floor Benthic Creatures living onthe seafloor Filter feeders: sponges, cnidarians (jellyfish, anemones, coral), mollusks (clams, oysters, mussels, scallops, snail, squid, octopus),arthropods (crab, shrimp, lobster), echinoderms (starfish, urchin) are particularly susceptible to turbidity. BISSO MARINE is cognizant of the varying and vital marine ecosystems and believes in a responsible balance between operational and environmental awareness.

3 PRE-PLOUGHING SURVEY & PLANNING Before a proper ploughing operation can be performed a feasible pipeline corridor must be established, historical metocean and local vessel data must be collected and a proper geophysical and hydrographical surveys must be done to fully understand the following: The historical wind, surface conditions, climate and storm frequency information The ocean wave, current and tide information The bathymetry and topography of the area Identify soil classification and densities, sub-surface The nature and composition of the seafloor along the ploughing route Identify seafloor obstructions, hazards and anomalies Specific historical and current surface vessel and other marine activities From the collection of geophysical, metocean, hydrographical and local vessel data, engineering must be performed to better understand the challenges of ploughing operations in specific areas. The processed data will determine and identify: Pre-ploughing route seafloor preparations (clearance of large boulders, sunken vessels etc.) Achievable burial depths (identify challenging or changing soil conditions and any sub-bottom limestone, coral or rock layers) Determine feasible and preferred methods of plough propulsion (pulling from a moored or a DP asset) Identify optimal operational timeframes by determining the most favorable operational windows Surface congestion areas and prohibited or restricted industrial activity zones From the processed geophysical, metocean, hydrographical and local vessel data subsequent engineering can establish safe and successful operational strategies, identify and estimate required plough pulling forces and estimated ploughing speeds. Safe and successful ploughing operations, methods and performances can only be realistically estimated after a proper evaluation is performed.

4 PLOUGH CONFIGURATIONS The only US based, owned and operated Pipeline Burial Plough ALL ploughing in US waters must be performed by Coastwise Eligible US Flagged assets governed by 46 U.S.C The environmentally friendly BISSO MARINE Advanced Burial and Backfill Pipeline Plough is a uniquely designed to be a Pre-Trenching, Post-Trenching Burial and Backfill plough mitigating minimal turbidity, seafloor or water column impact. This unique design uses the one chassis for two very different functions which reduces the footprint, weight and expense of mobilizing two different ploughing tools: one for burial and a separate for backfill. The conversion between the two different functions is easily done in about 72 hours at or near the work site by first placing the plough on the deck of a barge, vessel or at a shoreside facility; then by removing the plough share and mouldboard unit and installing the two backfill blades. The plough can rapidly be transported worldwide by ship or moved by tug and barge. During a project the plough can be transported on the deck of a derrick materials barge and launched and handled by an attending lift vessel. The plough is installed on a pipeline with diver or ROV assistance and observation. Once the Plough is safely on a pipeline, All operations are remotely controlled via an umbilical using electronic monitoring and operational control systems to monitor plough shares position, towing/pulling forces, pitch, roll, water depth, trench depth, vertical and horizontal forces on the pipeline, pipeline tracking, Mesotechand system diagnostics.

5 PLOUGH SPECIFICATIONS Maximum Ø pipe diameter (through plough) 36 (915mm) Fully Variable Trenching Depth Depends on Soils Vane Shear and Bollard Pull Force Ploughing speed Variable < 750 (.24 km) to > 6,500 (2 km) Per Day, Depending on Soils Pre-Trenched/Single Pass Burial Depth 7 (84 )(2.13m)* Cover Depth 3 (.91m) Top of Pipe - up to 48 Ø total OD ** Cover Depth 4 (1.21m) Top of Pipe - up to 36 Ø total OD ** V-Trench with 35 Slope up to 4.5 (1.37m) & 25 Slope from 4.5 (1.37m) to 7 (2.13m) Weight: 116 st (105 mt) dry / 100 st (90 mt) submerged / 56 st (50mT) With Air Buoyancy Stable on 105 psf (5 kpa) Vane Shear Soils Without Excessive Plough Sinkage or Bouyancy Requirement Designed For Glacial Till and High Vane Shear Soils Operational Water Depth ~10 (~3.04m) to 300 (91.4m) *** Designed for 220 st (199.5 mt) Sustained Pull / up to 275 st (250 mt) Exceptional Load - Ploughing*** Designed for 165 st (150 mt) Sustained Pull / up to 220 st (200 mt) Exceptional Load - Backfill*** * Can be modified for deeper burial depth ** Exact number of passes depends on seafloor composition confirmed by geotechnical survey *** Shallow depths are dictated by Barge/Vessel draft, bollard pull and access, NOT plough functionality

6 PLOUGH SPECIFICATIONS continued Vertical Tow Angle 0-15 / Horizontal Tow Angle Within 5 of Straight Ahead Pipe Support Capacity: 33 st (30 mt) Vertical / 16.5 st (15 mt) Lateral Fore and Aft Pipe Handling Roller System 33 st (30 mt) Plough Shares and Pipe Handling Roller System Are Hydraulically Controlled With Fail Safe Opening Systems Ploughed Trench to Depth Of 7 (2.13m) Has Backfill Return of > 90% of Trenched Spoil Four Point Lift Arrangement Umbilical 1000 (300m) x 1.5 (38mm) Double Steel Wire Armored Surveillance: Up to 6 Cameras and 5 Sonar Heads, Pipe Tracking and Mesotech Available ADVANTAGES: Pre-Trenching & Post-Trenching Capabilities Backfill of Trench with Ploughed Overburden Minimal Environmental Impact and Turbidity Mitigation On Board Electronic Pipe Monitoring Available Winch pulled or DPII towed Maximum Operational Dimensions: (22.73m) width (backfilling) (23.7m) length (ploughing) (8.77m) height (ploughing) 11 9 (3.58m) plough share opening (2.57m) aft opening between backfill blades

7 PLOUGH OPERATIONAL MONITORING The performance of the plough is monitored from a control station which provides the operator with real time data. The pipeline is monitored for stresses and the plough can provide the operator with exact force loads before a problem occurs. In addition to monitoring the forces on the pipeline and the depth of burial, the plough is equipped with sensors to monitor trench conditions and conditions out in front of and behind the plough.

8 INITIATING PIPELINE OPEN SHARES FRONT VIEW

9 INITIATING PIPELINE CLOSED SHARES FRONT VIEW

10 PLOUGHING TO BURIAL DEPTH

11 PLOUGHING TO BURIAL DEPTH

12 PLOUGH BACKFILL ADJUSTMENTS PLOUGHING TO BACKFILL PIPELINE

13 PLOUGHING TO BACKFILL PIPELINE

14 EXTREME SHALLOW WATER PLOUGHING

15 SUPPORTING PIPELINE PLOUGHING US Flagged D/B BOAZ supporting ploughing operations Northeastern US