The invention concerns a process and a device for laying a subsea pipeline according to the J-lay or S-lay method wherein straight sections are mounted onshore, dried and degassed then closed by plugs. The sections are loaded on a pipe-laying ship, are separated from their plugs before the welding. At the welding of each bulkhead a short pumping is operated to reduce the pressure in the part of the annulus located between the two last bulkheads and then the opening leading to the annulus are sealed.

A method of providing motion compensation of a subsea package with a synthetic rope comprising attaching the synthetic rope to the subsea package, supporting a first gripper with a wire rope from a winch capable of motion compensation control characteristics and gripping the synthetic rope with the first gripper, supporting a second gripper with a second wire rope, and repeating the following sequence: lowering the first gripper, the synthetic rope, and the subsea package a first distance, gripping the synthetic rope with the second gripper, releasing the first gripper from the synthetic rope, raising the first gripper the first distance, gripping the synthetic rope with the first gripper, releasing the second gripper from the synthetic rope, such that when the subsea package is lowered proximate the subsea landing location the winch capable of operating with motion compensation characteristics can operate to compensate for the vessel motion and smoothly lower the subsea package to the subsea landing location.

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 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.

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).

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).

An integrity monitoring system for a lined pipeline is provided for monitoring the integrity of a polymer liner in a host pipe. Methods and apparatus are described by which a lined pipeline is provided with such an integrity monitoring system. Sensor cable is able to bridge a joint between sections at lined pipe, for example by routing the sensor cable across the joint via a channel in an electrofusion fitting or by connecting successive lengths of sensor cable via pass-throughs in an electrofusion fitting. Advantageously, the sensor cable is disposed within a continuous annulus between linings and host pipes, and the continuous annulus is maintained across pipe joints using electrofusion fittings.

An integrity monitoring system for a lined pipeline is provided for monitoring the integrity of a polymer liner in a host pipe. Methods and apparatus are described by which a lined pipeline is provided with such an integrity monitoring system. Sensor cable is able to bridge a joint between sections at lined pipe, for example by routing the sensor cable across the joint via a channel in an electrofusion fitting or by connecting successive lengths of sensor cable via pass-throughs in an electrofusion fitting. Advantageously, the sensor cable is disposed within a continuous annulus between linings and host pipes, and the continuous annulus is maintained across pipe joints using electrofusion fittings.