Offshore pipeline laying system and method for raising and lowering a subsea pipeline and one or more accessories it includes

Abstract

The present invention relates to a marine pipeline laying system (1) and method for lowering and / or raising a subsea pipeline and one or more accessories (30) it comprises, said system (1) comprising: pipeline entry into the water Device (10), pipe clamps (6a, 6b), accessory connection device and controlled load lifting device (19). The accessory handling device (20) is configured to include an accessory transport track (21) and a cart (23) adapted to engage and support one of the one or more accessories such that the accessory The operating device (20) is adapted to engage said accessory in an engaged position, to position said accessory at a pipe connection location above a pipe clamp (6a, 6b) in a working line (11), wherein said accessory Can be connected to the pipe and support and allow movement of the accessory between an engaged position and a pipe connection position.

Description

technical field

[0001] The present invention relates to a marine pipeline laying system and method for lowering and / or raising a subsea pipeline and one or more accessories comprised by the subsea pipeline. Background technique

[0002] In most subsea pipelines to be laid it is necessary to install accessories, also known as assemblies on the ends of the pipeline and / or at one or more intermediate positions along the pipeline. These attachments are often very large and heavy, and are generally designed to be welded to the pipe. Examples of such accessories are: primary assemblies, pipe end termination facilities (PLETs), branch pieces, inline SLED assemblies, inline manifolds, pipe valves, tee assemblies with support structures and anti-settling plates.

[0003] Such pipe fittings should normally be welded in line with the pipe. The attachment typically has pipe connection parts at its opposite ends to connect subsea pipes to these pipe connection parts. However, it is al...

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