Abstract: A seabed-to-surface riser system is disclosed. The seabed-to-surface riser system has a group of subsea riser supports that each support riser pipes extending from the seabed to mid-water. Jumper pipes extend from there to a floating production, storage and offloading (FPSO) offset horizontally from the riser support in a flow direction. The group of riser supports is disposed to one side of the surface installation. Laterally-extending lines are attached to at least the outermost riser supports of the group. Those lines apply mutually-opposed stabilizing forces to those outermost riser supports in directions transverse to the flow direction.

Abstract: Disclosed is a riser including a plurality of pipelines. In one example there are three such pipelines extending from the seabed toward the surface and having an upper end supported at a depth below the sea surface. In one embodiment, a first of the pipelines acts as a central structural core, and the other pipelines are arranged around the first pipeline. In another embodiment, three pipelines are arranged around a structural core. In each case, the first of the pipelines can be a fluid injection line, and the other pipelines are production lines. Also disclosed is a riser having buoyancy along at least a part of its length. The buoyancy results in the riser having a generally circular cross-section, the circumference of which is non-contiguous. Methods of installing such risers are also described.

Abstract: A seabed-to-surface riser system is disclosed. The seabed-to-surface riser system has a group of subsea riser supports that each support riser pipes extending from the seabed to mid-water. Jumper pipes extend from there to a floating production, storage and offloading (FPSO) offset horizontally from the riser support in a flow direction. The group of riser supports is disposed to one side of the surface installation. Laterally-extending lines are attached to at least the outermost riser supports of the group. Those lines apply mutually-opposed stabilizing forces to those outermost riser supports in directions transverse to the flow direction.

Abstract: Disclosed is a riser including a plurality of pipelines. In one example there are three such pipelines extending from the seabed toward the surface and having an upper end supported at a depth below the sea surface. In one embodiment, a first of the pipelines acts as a central structural core, and the other pipelines are arranged around the first pipeline. In another embodiment, three pipelines are arranged around a structural core. In each case, the first of the pipelines can be a fluid injection line, and the other pipelines are production lines. Also disclosed is a riser having buoyancy along at least a part of its length. The buoyancy results in the riser having a generally circular cross-section, the circumference of which is non-contiguous. Methods of installing such risers are also described.

Abstract: Disclosed is a riser comprising a plurality of pipelines. In one example there are three such pipelines, extending from the seabed toward the surface and having an upper end supported at a depth below the sea surface, wherein, in one embodiment a first of said pipelines acts as a central structural core, the other pipelines being arranged around said first pipeline. In another embodiment three pipelines are arranged around a structural core. In each case, the first of said pipelines may be a fluid injection line, said other pipelines being production lines. Also disclosed is a riser having buoyancy along at least a part of its length, said buoyancy resulting in said riser having a generally circular cross-section, the circumference of which being non-contiguous. Methods of installing such risers are also are also described.

Abstract: Methods and apparatuses for the production of hydrocarbons from an offshore reservoir are disclosed. The hydrocarbons are produced using at least one spur (or flowline), and at least one riser conduit to transport said hydrocarbons from the seafloor to a point at or near the sea surface, wherein an artificial lift method, such as the injection of a lifting gas, is used to help transport said hydrocarbons from the reservoir to said point at or near the surface, and wherein said artificial lift method is applied to said hydrocarbons at a point along the at least one riser conduit, substantially above said seafloor.

Abstract: Disclosed is a riser comprising a plurality of pipelines. In one example there are three such pipelines, extending from the seabed toward the surface and having an upper end supported at a depth below the sea surface, wherein, in one embodiment a first of said pipelines acts as a central structural core, the other pipelines being arranged around said first pipeline. In another embodiment three pipelines are arranged around a structural core. In each case, the first of said pipelines may be a fluid injection line, said other pipelines being production lines. Also disclosed is a riser having buoyancy along at least a part of its length, said buoyancy resulting in said riser having a generally circular cross-section, the circumference of which being non-contiguous. Methods of installing such risers are also are also described.

Abstract: Apparatus for the connection and/or disconnection of a marine riser to a floating vessel comprising, in a main embodiment, a plurality of connecting lines. The, lower ends of these connecting lines are attached to the riser and are arranged to be moveable between a first helical configuration which allows connection, via a turret, between the riser and the floating vessel and a second helical configuration wherein said connecting line is disconnected and. retracted from said floating vessel. A method of installing said connecting lines is also disclosed.

Abstract: A method of controlling the heat transfer properties of a sub-sea conduit having inner and outer walls (800, 802) and a gas-permeable space (804) between the walls providing thermal insulation, the method comprising varying the pressure of a gas within the space between values above and below a critical pressure range at which thermal conductivity of the gas exhibits a high rate of change.

Abstract: Apparatus for the connection and/or disconnection of a marine riser to a floating vessel comprising, in a main embodiment, a plurality of connecting lines. The, lower ends of these connecting lines are attached to the riser and are arranged to be moveable between a first helical configuration which allows connection, via a turret, between the riser and the floating vessel and a second helical configuration wherein said connecting line is disconnected and. retracted from said floating vessel. A method of installing said connecting lines is also disclosed.

Abstract: A method of controlling the heat transfer properties of a sub-sea conduit having inner and outer walls (800, 802) and a gas-permeable space (804) between the walls providing thermal insulation, the method comprising varying the pressure of a gas within the space between values above and below a critical pressure range at which thermal conductivity of the gas exhibits a high rate of change.