Mitigation Of Buckling In Subsea Pipelines
AssigneeSubsea 7 Norway AS
InventorsChristian Linde OLSEN, Fartein Thorkildsen
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Abstract
A subsea pipeline (14) has a friction-reducing outer coating, treatment or finish (30) that extends along discrete regions mutually spaced along the length of the pipeline. During laying, curvature is imparted to the pipeline (14) along its length, for example by the residual curvature method or by snake-lay, to create expansion loops (26) of increased curvature relative to intermediate portions (28) of the pipeline (14) that join those loops (26). Each of the loops (26) is coincident with a respective one of the regions that bear the friction-reducing outer coating, treatment or finish (30). This facilitates lateral movement of the loops (26) relative to the seabed (16) to mitigate and control buckling in use of the pipeline (14).
Claims23
A method of laying a subsea pipeline, the method comprising:
- launching the pipeline from an installation vessel, the pipeline having a friction-reducing outer coating, treatment or finish extending along discrete regions that are mutually spaced along the pipeline;
- and
- imparting curvature to the pipeline along its length during laying to create expansion loops of increased curvature relative to intermediate portions of the pipeline that join those loops, each of those loops being coincident with a respective one of the discrete regions.
The method of any preceding claim, comprising imparting said curvature to the pipeline by steering the installation vessel along a corresponding course during laying.
A method of making a subsea pipeline, the method comprising applying a friction-reducing outer coating, treatment or finish to a pipeline made of steel, said outer coating, treatment or finish extending along two or more discrete regions that are mutually spaced along the pipeline.
A subsea pipeline laid with curvature along its length, the pipeline comprising expansion loops of increased curvature relative to intermediate portions of the pipeline that join those loops, wherein the loops are coincident with respective discrete regions of the pipeline each having a friction-reducing outer coating, treatment or finish, said regions being mutually spaced apart along the length of the pipeline.
Dependencies are inferred from the claim text.