Abstract: Water that is produced during offshore hydrocarbon processing, such as hot produced water accompanying hydrocarbons taken from subsea reservoirs, or cold water resulting from heating LNG (liquified natural gas) to convert it to gas, is changed in temperature to be closer to that of the surrounding sea using apparatus of minimal cost. The apparatus includes a mixer tube (52) that lies totally submerged in the sea and a nozzle (54) that receives the produced water and that has a nozzle end (76) lying in a middle portion of the mixer tube. A location of the mixer tube middle portion at the nozzle end has an inside diameter (A) much larger than the nozzle end outside diameter (B) to induce the through flow of sea water from the surrounding sea through the mixer tube. The produced water is pumped to a high enough pressure to create turbulence in the mixer tube immediately downstream of the nozzle end to better mix the produced and sea waters.

Abstract: The invention relates to a fluid transfer system, in particular for LNG in which an articulated vertical and horizontal mooring arm are suspended from a support on the processing vessel. Independently moveable ducts, for instance cryogenic hard piping are placed parallel to the mooring arms such that a transfer system is obtained in which is the mooring forces are insulated from the fluid transfer line with which rapid connection and disconnection is possible and which provides a large yaw resistance. In a preferred embodiment, the mooring system comprises two vertical arms connected to a triangular horizontal yoke attached to the bow of the LNG-carrier for improved yaw resistance.

Abstract: The invention relates to a hydrocarbon transfer system comprising a first structure (8) carrying an articulated arm (4,5,61,62). The system has at a free end (64) a first connector part (13,43,65), and a vessel (7) comprising a second connector part (47,48,70), wherein each connector part comprises a housing (72,73) with at least two fluid ducts (66,67,68,69) within said housing.

Abstract: The invention relates to an offshore structure with a floating support carrying process equipment and a processing column supported thereon. The processing column is connected via a hinging connection such as to maintain its upright position under low frequency inclinations of the vertical centre line of the floating support. Hereby, efficiency of liquid and gas contacting in the column under sea going conditions is maintained.

Abstract: A vessel includes a riser and/or tendon tensioning construction. A connector, such as an arm or deck structure, is suspended from cables movable relative to cable guides. The connector carries two or more risers and/or tendons extending from a subsea structure to above water level. The free ends of the cables are attached to weights for exerting a tensioning force on the risers, which are substantially decoupled from pitch, roll and heave motions of the vessel.

Abstract: The invention relates to a hydrocarbon transfer system (1) in which a floating construction (2) such as a FPSO is connected to an offloading buoy (3) via a submerged offloading pipeline (10). The motions of the buoy are de-coupled form the pipeline (10) via connection of the pipeline by a support member (7) and connecting member (8) while the pipeline (10) is extendable in a length direction to compensate for drift phenomena.

Abstract: A method of connecting two or more elongate connection members (105) between the seabed and a floating vessel (106) carrying a connector (102) which is suspended from the vessel by at least two spaced apart suspension members for relative displacement of the connector with respect to the vessel, at least one suspension member being connected to tensioning elements (109, 109′) for exerting an upward force on the connector. The method comprises the steps of: a) attaching one or more connection members to the connector, b) increasing the tensioning force of the tensioning elements, or vice versa, and c) repeating steps a and b until the connection members are installed between the vessel and the seabed.

Abstract: A method of mooring a vessel to a subsea anchoring element (1) connected to the seabed, and comprising a chain section (3) which is not longer than half the water depth, and which is at or near its free end provided with a coupling member (4), is characterised by the steps of: lowering a multi-strand anchor line (9) from a vessel (8), the multi-strand anchor line (9) being at its free end attached to a connector (10), and attaching the connector (10) to the coupling member (4). The present disclosure also provides an anchor line repair or exchange method comprising the steps of: disconnecting the first multi-strand anchor line (16) from the chain section, lowering a second multi-strand anchor line (9) from a vessel (8), the second multi-strand line (9) being at its free end attached to connector (10), and attaching the connector (10) of the second multi-strand line (9) to the coupling member (4).

Abstract: The invention relates to a vessel having an elongated shape, and being moored to the sea bed in a substantially fixed orientation. The vessel comprises at least along its longitudinal sides, near keel level, two transverse skirts having such a width that the natural roll period of the vessel is above a predetermined period, the natural roll period of the vessel without the skirts being below said predetermined period.

Abstract: The invention relates to a storage structure having a fluid transfer boom for transfer of cryogenic liquids such as liquified natural gas (LNG) from a first storage structure to a vessel. The boom has two arms which are rotatably connected at their first ends via a swivel joint. In one embodiment a liquified natural gas duct is supported within the first and second arms which form a gas tight housing around the liquified natural gas duct. The transfer boom according to the present invention provides a redundant containment system wherein the LNG duct is supported by the structurally strong and self-supporting transfer boom which confines the natural gas in case of a leak in the inner LNG duct. In a further embodiment the transfer boom comprises seven swivel joints in total such that rotation in all directions is possible when the vessel is moored to the storage structure and has to cope with relative motions of roll, pitch, yaw, heave, sway and surge.

Abstract: The invention relates to floating mooring construction (1) comprising a vessel (2) having a hull (35) with a cavity (9) for receiving a mooring buoy (8) carrying at least one flowline (13), and a pulling device (22, 24) connected to the mooring buoy for pulling the buoy towards the vessel. A flexible element (27) is comprised between a wall of the recess (9) and the buoy. The invention is characterised in that the vessel comprises a turret (5) around which the vessel can weathervane, the recess (9) being provided in the lower part of the turret (5), wherein the buoy (8) comprises near its lower end an annular groove (26) in which the flexible element (27) is seated, the outer surface of the flexible element including a sharp angle (&agr;) with a center line (21) of the buoy. The buoy is attachable to the turret by the pulling device (22, 24) pulling the buoy into the cavity (9) and compressing the flexible element (27) against the wall of the cavity (9).

Abstract: An anchoring system includes a vessel and one or more anchor lines extending from a first anchor to a pulling device on the vessel and from there on to a second anchor. The anchor line may extend transversely to the length direction of the vessel, or may extend parallel to the length direction of the vessel, offset from the longitudinal or transverse centre-lines. The anchoring system provides an active semi-weathervaing capability whereby heave and roll motions may be significantly reduced. Accurate station keeping maybe achieved with a relatively small number of pulling devices, the pulling force of which can be relatively small.

Abstract: The invention relates to a storage structure having a fluid transfer boom for transfer of cryogenic liquids such as liquified natural gas (LNG) from a first storage structure to a vessel. The boom has two arms which are rotatably connected at their first ends via a swivel joint. In one embodiment a liquified natural gas duct is supported within the first and second arms which form a gas tight housing around the liquified natural gas duct. The transfer boom according to the present invention provides a redundant containment system wherein the LNG duct is supported by the structurally strong and self-supporting transfer boom which confines the natural gas in case of a leak in the inner LNG duct. In a further embodiment the transfer boom comprises seven swivel joints in total such that rotation in all directions is possible when the vessel is moored to the storage structure and has to cope with relative motions of roll, pitch, yaw, heave, sway and surge.

Abstract: The invention relates to a method of connecting a first floating structure (1, 16, 25, 41) to the seabed, comprising the steps of: providing a second floating structure (2, 18, 26, 40), anchored to first and second anchoring points (6, 7; 22, 23; 32, 33; 47) respectively on the sea bed via at least two anchor lines (4, 5; 19, 20; 30, 31; 43, 45), attaching the second floating structure to the first structure via a pulling device (13, 24, 35, 46), on the side of the first anchor line, displacing the first floating structure (1, 16, 25, 41) away from the second anchoring point (7; 22, 33, 47) towards the first anchoring point (6, 23, 32), disconnecting the first anchor line (4, 20, 30, 45) from the second floating structure (2, 18, 26, 40) while maintaining a pulling force on the second anchor line (5, 19, 31, 43) via the pulling device, and attaching the first anchor line (4, 20, 30, 45) to the first floating structure (1, 16, 25, 41).

Abstract: A swivel (40) includes an outer (41) and inner annular wall (42). A toroidal chamber (44) is defined between the outer and inner walls and opposing peripheral faces of the walls define an upper (45) and lower gap (52) extending respectively upwardly and downwardly from the toroidal chamber. The upper and/or lower gap has a first section (46) extending axially, a second section (47) transverse to the first section (46) and a third section (48) extending substantially parallel to the first section (46). A seal (50, 51) is placed in the second (47) or the third (48) section of the upper and/or lower gap (25, 52), the seal having two flexible legs (61, 62) arranged in a generally u-shaped or v-shaped orientation. The gap near the area of the seal is filled with a sealing fluid during use.

Abstract: A vessel includes a riser and/or tendon tensioning construction. A connector, such as an arm or deck structure, is suspended from pivot arms on the vessel. The connector carries two or more risers and/or tendons extending from a subsea structure to above water level. The free end of the pivot arms is attached to a weight for exerting a tensioning force on the riser which is substantially decoupled from pitch, roll and heave motions of the vessel.

Abstract: A method of connecting two or more elongate connection members (105) between the seabed and a floating vessel (106) carrying a connector (102) which is suspended from the vessel by at least two spaced apart suspension members for relative displacement of the connector with respect to the vessel, at least one suspension member being connected to tensioning elements (109, 109′) for exerting an upward force on the connector. The method comprises the steps of: a) attaching one or more connection members to the connector, b) increasing the tensioning force of the tensioning elements, or vice versa, and c) repeating steps a and b until the connection members are installed between the vessel and the seabed.

Abstract: A vessel includes a riser and/or tendon tensioning construction. A connector, such as an arm or deck structure, is suspended from pivot arms on the vessel. The connector carries two or more risers and/or tendons extending from a subsea structure to above water level. The free end of the pivot arms is attached to a weight for exerting a tensioning force on the riser which is substantially decoupled from pitch, roll and heave motions of the vessel.

Abstract: A method of connecting two or more elongate connection members (105) between the seabed and a floating vessel (106) carrying a connector (102) which is suspended from the vessel by at least two spaced apart suspension members for relative displacement of the connector with respect to the vessel, at least one suspension member being connected to tensioning elements (109, 109′) for exerting an upward force on the connector. The method comprises the steps of: a) attaching one or more connection members to the connector, b) increasing the tensioning force of the tensioning elements, or vice versa, and c) repeating steps a and b until the connection members are installed between the vessel and the seabed.

Abstract: A method of constructing SPAR buoys comprising an elongate floating body (1) and a deck structure (2). The elongate body (1) is transported to the mooring site in its horizontal position. During erecting of the floating body (1) by ballasting it with water and alignment with the deck structure (2), the deck structure (2) remains attached to its buoyancy member (7). Hereby the use of large derricks can be avoided which provides a substantial cost reduction. After erecting the floating body, the body (1) may be ballasted to pass below the floating deck structure (2). Alternatively, the deck structure (2) may be deballasted or pulling cables (14) may be used to pull the coupling member (4) of the floating body (1) into contact with the coupling member (12) of the deck construction. Alternatively, the floating body (1) is at its upper ends connected to the deck structure (2) via a pivoting connection (22) such that during coupling the floating body may be hinged against the deck structure (2).