Subsea 7 Limited

Coflexip

Subsea 7 Contracting (uk) Limited

John Duncan Cruickshank

Herv&eacute; De Varax

Jean-Baptiste Pose

A turntable assembly for performing welding or other operations in a pivotably-mounted J-lay tower is disclosed. The assembly includes an annular turntable supported by a base frame to turn about a pipe string in use and a tilt-compensating mechanism acting on the base frame to level the turntable as the tower pivots in use. The tilt-compensating mechanism includes at least one support that is driveable up and down with respect to the tower. In the embodiment disclosed, the support is a carriage movable along an upright track that pivots with the tower.

Welding and other operations during J-lay pipelaying

A method of abandoning a pipeline during subsea pipelaying from a pipelay vessel includes suspending the pipe string from a tendon element of an abandonment string and engaging further tendon elements to an upper end of the abandonment string while lowering the pipe string to a handover depth. At the handover depth, tension is applied via a wire to the top of the pipe string at an acute angle to the launch axis. This deflects the pipe string from the launch axis into axial alignment with the wire to transfer the weight load of the pipe string to the wire, whereupon the abandonment string can be decoupled from the pipe string. Recovery of the pipeline from the seabed can be effected by a reverse process.

Improvements relating to abandonment and recovery of pipelines

An elongate sling section is disclosed. The elongate sling is cooperable with like sling sections to form a sling for use in abandonment or recovery of a pipeline. The sling section includes end-pieces at five opposite ends and complementary connector formations associated with each respective end-piece. Each connector formation is cooperable, in use when forming a sling, with a complementary connector formation of a neighbouring sling section in the sling. The sling section further includes a tensile load-bearing sling element extending between the end-pieces and a sleeve around the sling element.

Abandonment and recovery of pipelines

A vessel for laying rigid tubular pipes has two vertically upright wheels for storing tubular pipe which is wound with plastic deformation. An inclinable laying davit is arranged approximately above a moon pool. An arched chute deflects the pipe at the top of the davit, followed down the davit by a pipe-straightener and tensioner. The mid-planes of the two adjacent wheels face approximately towards the davit, and the mid-planes intersect in the vertical longitudinal mid-plane of the vessel.

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Woodlands of Durris, United Kingdom

John Duncan Cruickshank