A support for an underwater pipeline, in particular configured to elevate an underwater pipeline on a bed of a body of water, with a connecting frame configured to fit to a portion of underwater pipeline extending along a longitudinal axis; and at least two legs, which are hinged to the connecting frame, and movable between a contracted configuration and an extended configuration in which they extend crosswise to the underwater pipeline to rest on the bed of the body of water.

A method for governing the elevation, attitude and structural integrity of a pressure-containing vessel in a body of liquid counterbalances flotation and incompressible ballast mediums against each other in separate serial compartments. Varying the quantity of incompressible ballast medium allows control of the elevation and attitude of the vessel. If the flotation medium is compressible, varying the quantity of flotation medium allows control of the ambient pressure of the vessel. The method facilitates floating and towing and laying of an undersea pipeline on, to and at a deep water site.

A method for governing the elevation, attitude and structural integrity of a pressure-containing vessel in a body of liquid counterbalances flotation and incompressible ballast mediums against each other in separate serial compartments. Varying the quantity of incompressible ballast medium allows control of the elevation and attitude of the vessel. If the flotation medium is compressible, varying the quantity of flotation medium allows control of the ambient pressure of the vessel. The method facilitates floating and towing and laying of an undersea pipeline on, to and at a deep water site.

A method is provided for installing a pipeline on the seabed from a marine pipelaying vessel, including initiation, pipelaying, and abandonment of the pipeline. An embodiment of the abandonment of the pipeline includes halting pipelaying and engaging a hang-off clamp with the pipeline at a position below one or more tensioners, transferring the weight onto the hang-off clamp and holding the seagoing pipeline in the firing line, severing the pipeline, connecting the initiation cable to the lower end of the pipeline held by the one or more tensioners, transferring pipeline tension onto the initiation cable, releasing the one or more tensioners, so that a section of the pipeline is held in the firing line between the pipeline diverter and the initiation cable, vacating the firing line by at least displacing both the pipeline diverter and the initiation cable sheave and thereby displacing said section of the pipeline from the firing line, arranging the A&R cable in the firing line, connecting the A&R cable to the upper end of the seagoing pipeline held in the firing line, releasing the hang-off clamp, and operating the A&R winch and thereby lowering the pipeline onto the seabed.

Method is for operating fluid-processing plant configured to generate and store pressurized fluid, and spaced apart from body of water. Method includes: (A) positioning variable-buoyancy assembly in body of water in such way that buoyancy force urges variable-buoyancy assembly to move toward surface of body of water; (B) positionally anchoring, at least in part, non-collapsible fluid-line assembly underground in such way that non-collapsible fluid-line assembly extends, at least in part, into body of water; (C) fluidly connecting, via non-collapsible fluid-line assembly, fluid-processing plant and variable-buoyancy assembly together in such way that non-collapsible fluid-line assembly conveys pressurized fluid between fluid-processing plant and variable-buoyancy assembly; and (D) transmitting an anchoring force, via non-collapsible fluid-line assembly, from ground to variable-buoyancy assembly in such way that anchoring force substantially counteracts buoyancy force acting on non-collapsible fluid-line assembly, and anchoring force substantially urges variable-buoyancy assembly to remain below surface of body of water.

A system includes a foundation with a post mounted on the foundation top surface and a pipe module configured to couple to the foundation. The pipe module has a yoke to cooperate with the post to engage the pipe module with the foundation. The pipe module is connected to the end of a pipeline and is configured to slide along the foundation responsive to longitudinal and angular movements of the end of the pipeline. A method includes deploying a foundation subsea and securing the foundation to a seafloor. The foundation has a post. The method includes deploying the pipe module via the pipeline suspended by a pipe module installation machine. The pipe module has a yoke. The method includes engaging the yoke with the post, paying out the pipeline to lower the yoke, and lowering and engaging the pipe module with the foundation.

A system includes a foundation with a post mounted on the foundation top surface and a pipe module configured to couple to the foundation. The pipe module has a yoke to cooperate with the post to engage the pipe module with the foundation. The pipe module is connected to the end of a pipeline and is configured to slide along the foundation responsive to longitudinal and angular movements of the end of the pipeline. A method includes deploying a foundation subsea and securing the foundation to a seafloor. The foundation has a post. The method includes deploying the pipe module via the pipeline suspended by a pipe module installation machine. The pipe module has a yoke. The method includes engaging the yoke with the post, paying out the pipeline to lower the yoke, and lowering and engaging the pipe module with the foundation.

A method of joining a first pipe section to a second pipe section includes positioning the two pipe sections in an end-to-end configuration to define therebetween a joint to be welded, measuring the degree of alignment of the pipe sections when they are in the end-to-end configuration in a position ready for welding, ascertaining the relative movement required of the pipe sections in order to improve their alignment, effecting the relative movement so ascertained, and welding together the two pipe sections. The method may include the use of geometric data of the end of the pipes in order to ascertain the relative movement required of the pipe sections. A control unit may be used to calculate, using such data, a target orientation that lines up the pipe sections. The measuring step may be performed using, for example, a laser or a camera and backlight.

A marine pipeline installation vessel and a method are provided for laying an offshore rigid pipeline in the sea, the vessel at least being adapted to carry out the rigid reel lay method. The vessel includes at least one vertical storage reel for the storage of a spooled rigid pipeline. A left and right reel support structure are provided to support the weight of the at least one storage reel. The left and right support structures are embodied to form a pivoting structure allowing an angular adjustment of the horizontal reel axis about a vertical axis to alter the angular position of the at least one storage reel.

This device comprises a drum (42) to be driven in rotation about a central axis (B-B′), wherein the drum (42) defines a circumferential casing (50) for winding the elongate element around the central axis (B-B′), wherein the elongate element is intended to form at least one turn around the central axis (B-B′) on the circumferential casing (50). It comprises a mechanism (44) for driving the turn(s) of the elongate element along the circumferential casing (50). The drive mechanism (44) comprises at least one assembly (80) following movement of the turn in a direction of movement (D) forming a non-zero angle with the local axis of the turn, taken at a contact region of the turn on the movement assembly (80).