Don Field Decommissioning Programme (pdf, 7.8MB) null - BP

DON-BP-001Don Field Decommissioning ProgrammeThe offshore work programme for decommissioning will typically have the followingmain phases: Pre-decommissioning Surveys Field AbandonmentThis phase includes tasks performed before the abandonment of the wells andincludes:– Flushing, disconnecting and recovering infield flowlines to isolate each well fromthe Don manifold and ultimately Thistle (flushing, disconnection and isolation taskscompleted in 2009)– Disconnecting and recovering control and chemical umbilicals to isolate each wellfrom the Don manifold and ultimately Thistle– Disconnecting pipelines from the subsea manifold after the pipelines have beenflushed and cleaned to the required level of cleanliness– Recovering flexiweight mattresses and grout bags at the Don manifold and Thistle– Recovering the production and water injection tie-in spoolpieces and valves atThistle and the Don manifold, water injection pipeline tie-in tee etc (refer toSection 10 for further details)– Recovering the Don manifold by DSV and cutting the manifold piles 3m below theexisting seabed level– Cutting out and recovering sections of pipe that emerge out of the seabed back tostable buried pipe, so that there is no possibility of a snagging hazard– Removing all features from the umbilicals (umbilicals cut back and buried)– Performing over-trawlability trials on grout formwork that will be left in situ andmade safe for other users of the sea– Performing a survey to identify any debris remaining on the seabed that mightaffect other users of the sea and removal of debris, if required Well AbandonmentReservoir abandonment and recovery of xmas treesThe programme plan will be updated during execution. This update will reflectperformance, technology developments, market capability and resource availability.2 References[13.1] DECC Guidance Notes – Decommissioning of Offshore Oil and Gas Installationsand Pipelines under the Petroleum Act 1998, http://www.decc.gov.uk/.Schedule13-2 May 2011