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

Don Field Decommissioning ProgrammeDON-BP-0011 IntroductionThis section describes the Decommissioning Programme 2 (as detailed in Section 1Paragraph 4) for the Don Field oil production and water injection pipelines, and thecontrol and chemical injection umbilicals, under the Petroleum Act 1998 [10.1]. Theprogramme has been prepared in line with the Department of Energy and ClimateChange (DECC) Decommissioning Guidance Notes [10.2].The pipelines and umbilicals are no longer required, and no potential commercial use canbe foreseen for them at their present locations. The 8in water injection pipeline (PL599)has known internal corrosion defects and the 8in production pipeline (PL598) wouldrequire to be intelligently pigged to determine its condition if further use could be found.The 3in chemical injection umbilical (PL600) is blocked and not fit for purpose and the 4incontrol umbilical has known electrical continuity problems.The pipelines and umbilicals are discussed separately in this section, which also: Describes the techniques that could be used to decommission the pipelinesand umbilicals Describes the pipelines and umbilicals, and their histories Describes the present condition of the pipelines and umbilicals, and any cleaning thatmay be required Identifies the potential decommissioning options Discusses the approach and method used to select the decommissioning optionsincluding a summary of the assessment of the various aspects based on which therecommended options were selected Recommends a decommissioning option for each item to be decommissionedBased on the similarity of the two 8in steel pipelines and the two umbilicals respectively,the two 8in steel pipelines are discussed together in Paragraph 5 and the two umbilicalsin Paragraph 6.2 Applicable Techniques for Decommissioning thePipelines and Umbilicals2.1 Options for Leave In Situ2.1.1 Leave In Situ with No Remedial WorkIt may be acceptable to leave pipelines and umbilicals in situ without any remedialaction, subject to suitable burial and environmental conditions. The assessment wascarried out based on the inspection history to date, combined with stable soil andenvironmental conditions. This is to confirm that the burial status will remain and thepipelines give no further threat to other sea users after being decommissioned.PipelinesMay 2011 10-1