Abstract: There are disclosed methods of and apparatus for interconnecting lined metal pipes (110, 120), applying in particular to the offshore oil and gas industry. Corrosion is a common problem in the industry. Lining pipes overcomes the problem, but welding sections of pipe together can be a complicated and time-consuming task, requiring dedicated and sophisticated tooling. More desirable is the ability to use conventional pipe-laying equipment (20, 40, 50, 60, 70, 80, 90) with little additional tooling. As such, there are disclosed methods and apparatus compatible with known offshore connection methods, particularly where the spacing of joints on the pipe is less than 100 m. The chosen technique will not significantly impact the laying rate of the lined pipe, compared with unlined pipe.

Abstract: There is disclosed a variety of arrangements for laying of rigid pipe from reeled storage and/or on-board welding fabrication. Thirteen independent aspects of the invention are identified. In one particular arrangement (FIGS. 3a-3b), a tilting lay tower (106) having two travelling clamps (210, 220) is provided centrally on a pipelay vessel with a radius control arch (140) pivotable to receive rigid pipe from either port or starboard lay paths. A vertical axis reel or carousel (104) is provided, within an arrangement of curved take-off arms (130, 134) and a large radius curved wall (128). By these means, pipe can be loaded onto the carousel either clockwise or anti-clockwise, and can be supplied to the lay tower via the port or starboard lay path. Continuous rigid product fabricated by a selection of welding lines (112, 114, 116) at the port side can be guided around the large radius wall either for reeling onto the carousel or for direct feeding to the lay tower.

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: The invention provides a marine riser apparatus (1) for use in the production of hydrocarbons from offshore wells and an associated method of installation of the apparatus at sea. The riser tower comprises rigid pipelines arranged in a riser tower bundle (2) and extending from a wellhead on the seabed (4) to a point below the sea surface where they are connected to flexible jumpers (3) which extend from the tower structure to connect the tower structure to a surface vessel or platform (5). The riser apparatus further comprises a buoyancy device (7) attached to the riser tower bundle, such that the buoyancy device is located above and exerts a buoyancy force on the riser tower, the buoyancy module also supporting an intermediate section of at least one of the jumpers.

Abstract: This invention relates to a marine riser tower (112, 114) for use in the production of hydrocarbons from offshore wells. The riser tower (112, 114) includes a plurality of fluid conduits, which may comprise production flow lines (P), gas-lift lines (G), water injection lines (W) and/or umbilicals (U). The conduits are supported in a single structure, and at least one of said conduits is provided with its own insulation within said structure.

Abstract: The invention relates to a marine riser tower having a plurality of rigid metallic conduits bundled together with a metallic tubular core. The conduits may include production lines for hydrocarbons, water injection lines, and/or gas lift lines. A production line or gas lift line is located within the core, while the water injection line is located outside the core.

Abstract: The relative position and orientation between two subsea structures (210, 212) are measured by ultra-short baseline acoustic metrology. Dual mode master/slave (220, 222) stations comprising a multi-transducer array are fitted in known position and orientation relative to each structure. The first station (220) is operated in master mode to determine the position and direction of the second structure (222) relative to the first (220). The second station (222) is operated in master mode to determine the position and direction data from both operations the apparatus calculates relative position and orientation between the structures. The dual mode stations can be replaced by a master station and a slave station, swapping places.

Abstract: This invention relates to a marine riser system for transferring fluid between a plurality of mutually separated locations on the seabed and a vessel (1) on the surface of the sea. The riser system comprises a submerged buoy (2), a plurality of risers suspended from the buoy (2) to the location on the sea bed and a plurality of flexible conduits (8) extending from the vessel to the submerged buoy (2). Connectors (7) carried by the submerged buoy (2) connect the flexible conduits (8) to the risers (6), each connector being remotely operable to disconnect all the flexible conduits from the risera. A central tether (5) may be provided during an installation phase only, until the risers (6) are in place and hold the buoy (2) by their own tension. Alternatively, the tether (5) may remain in place, and tensioned to limit vertical motion of the buoy.

Abstract: There is provided method and apparatus for buoyancy distribution along a substantially vertical submarine structure (100), in which the structure is provided with multiple modules (110), slidably mounted to the structure such that when vertically deployed at sea the modules are free to adjust their positions up or down the structure by sliding, the force of each module acting upon the module above it rather than locally along the structure, resulting in the cumulative force (460) from the modules acting substantially against the top of the structure. Forces between modules may be evenly distributed by use of compliant intermediaries (310).

Abstract: Hydrocarbon liquids are transported from a subsea welihead to an above-surface hydrocarbon processing facility along a pipe-in-pipe flowline. The flowline is a pipe placed coaxially within an outer carrier pipe and the annulus between the pipes is filled with thermally insulating material. The hydrocarbon liquids have their temperature maintained above solidification/precipitation temperature by heat from an active heating system. Hot liquid, preferably hot water, is passed along the annulus, either along a single pipe or multiple pipes installed in the insulation-filled annulus, or along an inner annulus formed by a water pipe added concentrically around the hydrocarbon-transporting inner pipe, inside the outer insulation-filled annulus. The water or other suitable liquid can be heated in a heater at or adjacent the subsea wellhead, or by a water heater in the above-surface hydrocarbon processing facility.

Abstract: A coupling device enabling rapid connection and disconnection of lifting wires or similar articles for attachment by an ROV to/from a submerged object comprising a main body portion (1), a hook potion (2), a closing member operated by a member (5) and a separate safety latch (4) arranged to lock the closing member when closed such that a load cannot escape the hook portion, the latch member and closing member being further arranged such that a gripping action (A, B) on two opposite sides of the body portion will automatically release said latch member and move the closing member into the open configuration while the device is held bodily under said gripping action, the closing member and latch member being spring biased so as to close and then lock the hook automatically when the grip is released.

Abstract: There is disclosed improved mooring apparatus and method suitable for use with large offshore vessels. To avoid deploying an anchor with a full weight of mooring chain, they are deployed separately. An anchor, such as a suction anchor (1), is fitted with a short chain (C1) with one end permanently connected (6) thereto and its free end temporarily placed in a chain locator (8), which is positioned so as to be accessible after deployment of the anchor to the seabed, minimising the potential for seabed material to cause disruption. The anchor with its short chain is deployed to the seabed and at some stage the free end of a mooring chain (C2) is lowered to and accurately guided (100) into the chain locator, such that both free ends align. A pin (101) is inserted by an ROV to interconnect the two chains, after which the combined mooring chain (C) is tensioned, withdrawing it from the chain locator.

Abstract: There is disclosed a hull for a sea-going vessel of displacement type having a flat bottomed midship section (100) of a constant cross-section which is substantially rectangular in cross section below the water line, and a converging bow portion (200) extending from said midship section, said bow portion having a curved transition (H) between the bottom (F) thereof and each hull side, the transition (C) between bottom and sides along the bilges in said midship section being relatively sharp, and in particular of radius less than 0.5 m, for example 0.025 m. The stern section (300) shape includes two propulsion arches each formed by an inclined, substantially part-cylindrical surface (S) extending from the flat bottom aft and upward to join the transom. The hull form provides a working vessel with extremely efficient roll-damping, yet sufficient transit speed for worldwide operation. The hull form can be constructed at relatively low cost, avoiding for the most part the need to form compound curves.

Abstract: Fiber reinforced flexible adhesive tape is used to bind an elongate article or bundle of articles during subsea laying operations and apparatus for laying the elongate articles. The apparatus includes at least one carrier for a tape spool arranged to rotate while moving bodily around the axis of the article during laying.

Abstract: There is disclosed a hull for a sea-going vessel of displacement type having a flat bottomed midship section (100) of a constant cross-section which is substantially rectangular in cross section below the water line, and a converging bow portion (200) extending from said midship section, said bow portion having a curved transition (H) between the bottom (F) thereof and each hull side, the transition (C) between bottom and sides along the bilges in said midship section being relatively sharp, and in particular of radius less than 0.5 m, for example 0.025 m. The stern section (300) shape includes two propulsion arches each formed by an inclined, substantially part-cylindrical surface (S) extending from the flat bottom aft and upward to join the transom. The hull form provides a working vessel with extremely efficient roll-damping, yet sufficient transit speed for worldwide operation. The hull form can be constructed at relatively low cost, avoiding for the most part the need to form compound curves.

Abstract: A pipe handling apparatus for laying elongate articles in deep waters includes a tiltable pipe handling structure housing a traveling clamp for holding and/or paying out under tension the elongate article and a fixed clamp. The traveling clamp is driven via an articulated rack located by a guide mechanism. The rack driven by a pinion drive mechanism and acts at a lower portion of the rack, such that the center of gravity of the apparatus is lowered, and loading in the structure is reduced.

Abstract: A pipe handling clamp for use on a deep water pipe laying vessel. The arrangement includes an array of piston members constrained to move along a first axis towards and away from a fixed support, and an hydraulically operated wedge member is driven transverse to the first axis so as to act between each piston member and the fixed support to effect motion to clamp a pipe. The axial piston and radial piston having complementary inclined surfaces, keyed to one another, so as to push and pull the radial piston in response to hydraulic pressure in the respective chambers.

Abstract: An apparatus for and a method of supporting a tubular member in a vertical orientation are provided. A first and length of pipe (1, 4) are supported at their upper ends by detachable collars (2a, 2b). The detachable collars (2a, 2b) are engageable with collar flanges (3a, 3b) which are attached to the pipes (1, 4). A pipe string elevator (5) is used to support the pipe (4) while an operator (70) attaches the lower end of pipe (4) to the upper end of the flange collar (3a).