Pipelaying
AssigneeAcergy France SAS
InventorsRomain Mille, Cesar Bourgeois
Life of this patent
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Abstract
An accessory is disclosed for a subsea pipeline such as an in-line tee having a rigid pipe support frame defining a pipe course and at least one carriage arranged to support a pipe or a fitting attached to a pipe. The carriage is movable with respect to the frame in a direction generally parallel to the pipe course. The carriage is attached to the frame via at least one angularly movable connection that allows a pipe or fitting supported by the carriage to tilt locally with respect to the frame as the pipe bends during laying. Pipe stiffness is therefore independent from the stiffness of the accessory. The stiffened section of the pipe is limited to a short length of the carriage. This is compatible with the small bending radius of the pipe on a stinger.
Claims48
A pipeline for laying subsea following fabrication on a surface vessel, the pipeline comprising:
- a rigid pipe that can be bent during laying;
- and
- an accessory attached in line with the pipe such that the accessory can be laid with the pipe into water and can touch down on the sea bed with the pipe, the accessory comprising:
- a foundation including one or more mudmats arranged to rest on the sea bed when the pipe is laid and movable with respect to the frame between a folded position and a deployed position,
- a rigid pipe support frame attached to the foundation defining a pipe course;
- and
- at least one carriage arranged to support the pipe or a fitting attached to the pipe, the at least one carriage being movable with respect to the frame in a direction generally parallel to the pipe course;
- wherein at least one angularly movable connection acting between the pipe or fitting and the frame allows the pipe or fitting supported by the at least one carriage to tilt locally with respect to the frame as the pipe bends during laying.
A method of laying a subsea pipeline from a vessel, comprising:
- overboarding an accessory attached in line with a rigid pipe directly or via a pipe fitting and that is longitudinally rigid in relation to the pipe, the pipe being movable longitudinally with respect to the in-line accessory when laid and being able to be bent during laying and the in-line accessory being able to be laid with the pipe into water and being able to touch down on the sea bed with the pipe and the accessory comprising
- a foundation including one or more mudmats arranged to rest on the sea bed when the pipe is laid and movable with respect to the frame between a folded position and a deployed position;
- attaching a rigid pipe support frame to the foundation;
- causing the pipe to bend about a center of curvature above or below the pipe;
- and
- accommodating said bending of the pipe by permitting angular movement of the pipe or the fitting where attached to the in-line accessory, by at least one angularly movable connection acting between the pipe or fitting and a frame of the in-line accessory wherein the accessory is installed with the pipe on the surface vessel.
Dependencies are inferred from the claim text.