A pipeline laying ship and an improved method of laying a pipeline in a marine environment is disclosed. The pipeline laying ship is a dynamically positioned barge or self-propelled dynamically positioned vessel with a hull having a deck area that supports a pair of reels. The reels are independently rotatable, and are position to generally port and starboard relative to one another. A pipe joint storage area is provided for containing multiple joints of pipe. One or more pipeline welding stations are provided on the deck next to the reels, the pipeline welding stations being positioned to join the joints of pipe together to form an elongated pipeline that can be wound upon a selected reel of said pair of reels. A tower is provided for guiding the elongated pipeline as it is unwound from a selected reel, the tower including at least a bend controller, a straightener and a tensioner. The welding stations and tower are each transversely and movably mounted upon the hull between the port and starboard positions that enable a pipeline to be welded and then wound upon either of the reels and to be unwound from either of the reels for launching to the sea bed via the tower.

Reel type pipeline laying ship and method

A method for installing an accessory onto a pipeline to be laid on the seabed, includes launching the pipeline from a first position of a tower in which the tower is at an angle α with respect to the vertical; stopping the launch of the pipeline, and hanging off the launched pipeline in a hang off module; positioning an accessory in a tower firing line; attaching the accessory to the launched pipeline in the hang off module and to at least one AR suspending the accessory and the launched pipeline from an AR disengaging the hang off module from the launched pipeline; pivoting the pipeline launch tower to an accessory launch position in which the tower is at an angle γ that differs substantially from angle α, such that a pipeline launch trajectory is created which is large enough to launch the accessory and the launched pipeline with the A&R system.

Marine pipeline installation system and methods

A pipe-laying vessel for S-laying a pipeline is provided, the vessel defining a pipe-laying path extending along the vessel. The vessel includes one or more track tensioners disposed along the pipe-laying path, and a travelling clamp assembly, including a clamp mounted for movement along a length of the pipe-laying path. The vessel may also include a fixed clamp assembly located on the pipe-laying path for clamping the pipeline in a fixed position on the pipe-laying path. At least one of the clamp assemblies may include a load bearing structure and a clamp wherein a downstream-facing portion of the clamp is in an abutting relationship with an upstream-facing portion of the load bearing structure such that a downstream force exerted, in use, by the pipeline on the clamp is transmitted to the load bearing structure.

Underwater pipe-laying

A system for direct electric heating of a subsea pipeline is disclosed in the form of a pipe-in-pipe flowline having an electrically conductive outer carrier pipe and an electrically conductive inner pipe or flowline arranged longitudinally, substantially concentrically within the outer pipe. An annulus is defined between the inner and outer pipes and a pipe insulating joint assembly structurally joins, but electrically insulates, the inner and outer pipes at a first end of the subsea pipeline. A power input provided on the surface facilities is electrically connected across the inner and outer pipes at the first end of the pipeline, and an electrical pathway completes the circuit by connecting the inner and outer pipes at the second end of the pipeline.

Direct electric pipeline heating

A marine pipelay vessel 10 is equipped with pipe laying apparatus 12. Mounted on a main support structure (22, figure 4) are a pipe supporting tower 18, a connecting station 14 for connecting together pipe sections 100, eg by welding, and a movable clamp (60, figure 4) for launching the pipeline, while a static clamp 58 is mounted on a hang-off structure. The main support structure and the hang-off structure are movable in a fore-and-aft direction, independently of each other. The static clamp 58 releasably secures the upper end of a previously launched pipe section, so that the lower end of the next pipe section to be launched from the tower 18 can be aligned with it for connection thereto. The pipe 100 is gripped alternately by the static clamp 58 and movable clamp (60, figure 4), to allow the pipe 100 to be launched from the vessel 10 in a stepwise manner by means of a repeating cycle in which the static clamp 58 is applied to the pipeline whilst the movable clamp (60, figure 4) is being raised to its uppermost stroke position, then transferring the load of the pipeline from the static clamp 58 to the movable clamp (60, figure 4), and then lowering the movable clamp (60, figure 4) to its lowermost stroke position. This process can be repeated until the required pipelength has been laid. Preferably, the mobile clamp (60, figure 4) and pipe supporting tower 18 are pivotally mounted on the main support structure (22, figure 4), while the static clamp 58 is pivotally mounted on the hang-off structure.

Marine pipelay system

An apparatus for near vertical laying of pipeline offshore. A support frame and movable deck on a lay vessel support a tower at the desired angle for pipe laying. The tower has a travel block that is movable between open and closed positions for receiving a pipe section and supporting the weight of the pipe or pipeline. The travel block is adapted for movement along the length of the tower for raising or lowering the pipe and pipeline. A pedestal that is movable between open and closed positions for receiving a pipe section and supporting the weight of the pipeline is positioned near the bottom of the tower and adapted to transfer the weight of the pipeline from the travel block to the pedestal without the need to open the travel block. A strongback with adjustable clamps is used to grasp a pipe section from a ready rack and transfer the pipe section into the tower for addition of the pipe section to the pipeline. The strongback is guided into and up the tower by rails. A stinger extends down from the lower end of the tower and is provided with clamps to grip the pipeline during operations. The main portion of the stinger may be pivoted up adjacent the lay vessel when pipe laying operations are not in progress.

Wilkins Jesse Ray

Papers

Apparatus for near vertical laying of pipeline

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