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

DON-BP-001Don Field Decommissioning Programme2.2 Subsea Wells RecoveryOn completion of well plugging operations, the xmas trees will be recovered and thenear-surface tubing and casing strings plugged and removed. The conductor strings willbe severed approximately 3m below the seabed. Xmas trees and guide baseswill be recovered.All recovered materials will be transported to shore for recycling.2.3 Don Manifold RecoveryIn line with the OSPAR Decision 98/3 [7.3] the Don manifold will be recovered in thefollowing stages:(1) Make the manifold hydrocarbon free.(2) Attach recovery rigging to the manifold and cut the two piles 3m below theexisting seabed level.(3) Recover the manifold by mobile drilling rig or DSV (exact details of the manifoldrecovery shall be provided by the removal contractor).3 Pipelines, Flowlines and UmbilicalsThe recommended option for the 8in production and water injection pipelines, and the3in chemical injection and 4in control umbilicals between Thistle and the Don manifold is‘leave in situ with selected recovery’ as these lines are trenched and fully buried.Pipeline and umbilical Northern Leg Gas Pipeline (NLGP) crossings will be deferred untilthe NLGP is decommissioned and the materials within the Thistle 500m zone will bedeferred until the Thistle is decommissioned.All flowlines and jumpers between the Don manifold and the wellheads willbe recovered.Refer to Section 10 for further details of the selected removal and disposal optionchosen for the pipelines, flowlines and umbilicals.4 Protection FeaturesIt is proposed that the following features are removed and disposed of onshore [7.4]: All features located within the immediate vicinity of the Don manifold All features located on the 3in chemical Injection umbilical All features located on the 4in control umbilical All grout bags and flexiweight mattresses on the 8in pipelines near the Don manifold(refer to Section 6 Figure 6.3, Areas 4 and 5)Selected Removal and Disposal Options7-4 May 2011