Methods of laying subsea pipeline (1300) on a seafloor comprising: providing a pipe laying vessel (1100), placing a spooling structure assembly (1200) on the seafloor, and laying the subsea pipeline (1300) in a loop around the spooling structure assembly and associated systems.

A carrier vehicle carries an unmanned subsea vehicle along an elongate body from a topside location to a subsea location. The carrier vehicle comprises a support structure configured to carry the unmanned subsea vehicle, and a translation mechanism comprising gripper arms connected to the support structure for causing the carrier vehicle to translate along the elongate body using a handover-hand action. The carrier vehicle can carry the subsea vehicle through a region of turbulence, such as a splash zone. This removes the need for special launch equipment to be installed on the platform to use the subsea vehicle.

A flexible deployment system is used to deploy subsea/downhole well equipment or modules from a multi-purpose vessel without requiring a moon pool and a derrick or tower. The deployment system may include the vessel and a deployment frame disposed on the vessel. The deployment frame includes a protruding section extending as a cantilever beyond an external edge of the vessel, and the protruding section includes an aperture formed therein to facilitate construction of the well equipment or modules through the protruding section. The deployment system also includes an actuation assembly coupled to the protruding section to selectively transition the protruding section to a collapsed, split, or retracted orientation out of a deployment path of the well equipment or modules. The system allows for controlled deployment of well equipment or modules including at least a string of downhole tools or tubulars coupled end to end from the side of the vessel in a single trip.

The invention relates to a vessel comprising a moonpool, a firing line hoist system, a stationary main deck for storing equipment and/or tubulars, and a mobile working deck having a front deck section and a rear deck section. The working deck can be moved between a working position and a transporting position. A rear deck lift system is provided for lifting and lowering a rear deck section between the working position and the transporting position. A front deck guide system is provided for guiding a front deck section in a substantially horizontal direction between the working position and the transporting position.

The invention relates to a vessel comprising a moonpool, a firing line hoist system, a stationary main deck for storing equipment and/or tubulars, and a mobile working deck having a front deck section and a rear deck section. The working deck can be moved between a working position and a transporting position. A rear deck lift system is provided for lifting and lowering a rear deck section between the working position and the transporting position. A front deck guide system is provided for guiding a front deck section in a substantially horizontal direction between the working position and the transporting position.

A self-propelled integrated ship for transporting and installing immersed tubes of an underwater tunnel comprises a first ship body and a second ship body which are parallel with each other, a connection structure is arranged between the first ship body and the second ship body; the first ship body, the second ship body and the connection structure are provided with hauling and hoisting devices, a loading space is formed between the first ship body and the second ship body and below the connection structure; a to-be-installed member is arranged in the loading space and is connected with the ship; and the first ship body and the second ship body are provided with propelling power devices and positioning devices. The loading space is provided in a lower part of the integrated ship, and a member to be transported is placed in the loading space and floated in the water, so that most of the weight of the member is shared by buoyancy. The member is transported to a designated site and installed precisely. Thus, the independent transportation and installation of immersed tubes of the underwater tunnel or similar large members with various sizes can be successfully realized by one self-propelled ship without assistance of other additional ships. Moreover, there is no need to close navigation lanes to other ships, thus not affecting the navigations of the other ships.

A self-propelled integrated ship for transporting and installing immersed tubes of an underwater tunnel comprises a first ship body and a second ship body which are parallel with each other, a connection structure is arranged between the first ship body and the second ship body; the first ship body, the second ship body and the connection structure are provided with hauling and hoisting devices, a loading space is formed between the first ship body and the second ship body and below the connection structure; a to-be-installed member is arranged in the loading space and is connected with the ship; and the first ship body and the second ship body are provided with propelling power devices and positioning devices. The loading space is provided in a lower part of the integrated ship, and a member to be transported is placed in the loading space and floated in the water, so that most of the weight of the member is shared by buoyancy. The member is transported to a designated site and installed precisely. Thus, the independent transportation and installation of immersed tubes of the underwater tunnel or similar large members with various sizes can be successfully realized by one self-propelled ship without assistance of other additional ships. Moreover, there is no need to close navigation lanes to other ships, thus not affecting the navigations of the other ships.

An improved system and method for laying on the seabed a pipeline and/or installing a subsea riser including one or more accessories are disclosed. In the system, a trolley rail for an auxiliary trolley is provided which includes a retractable trolley rail part supported by the tower via an associated mobile rail support assembly. Displacement of the retractable trolley rail part together with the auxiliary trolley when arranged on said retractable trolley rail part with respect to the tower is allowed, between an active position, wherein the auxiliary trolley is positioned to engage on an accessory in the firing line, and a retracted and non-operable position wherein a clear envelope about the firing line is created.

An improved system and method for laying on the seabed a pipeline and/or installing a subsea riser including one or more accessories are disclosed. In the system, a trolley rail for an auxiliary trolley is provided which includes a retractable trolley rail part supported by the tower via an associated mobile rail support assembly. Displacement of the retractable trolley rail part together with the auxiliary trolley when arranged on said retractable trolley rail part with respect to the tower is allowed, between an active position, wherein the auxiliary trolley is positioned to engage on an accessory in the firing line, and a retracted and non-operable position wherein a clear envelope about the firing line is created.

A method for burying a pipeline in a bed of a body of water which includes: making a trench with a bottom surface in a bed of a body of water via a bed working vehicle advanced in an advancing direction; advancing a floating unit in the body of water; releasing a pipeline in the body of water via a tensioner and along a lay device tilted in an adjustable manner and constrained to the floating unit; guiding the pipeline to the bottom surface of the trench via a guide vehicle advanced on the bed of the body of water; and controlling the tensioner, the floating unit, the lay device, the bed working vehicle, and the guide vehicle to minimize stress along the pipeline.