Abstract: The invention relates to a floating lowering and lifting device having a floating structure and a lifting unit lowerable from the floating structure towards the sea bed, the lifting unit having a chamber with at least one gas-inlet opening in its wall and an equalization opening in its wall, a gas supply mechanism being connected to the gas inlet opening, the device having a controller connected to the gas supply mechanism for controlling a gas supply rate to the chamber. The chamber has a releasable coupling member for releasably attaching to a load and is connected via a lifting cable to a take up device on the floating structure for lengthening and shortening the lifting cable.

Abstract: The invention relates to a floating lowering and lifting device having a floating structure and a lifting unit lowerable from the floating structure towards the sea bed, the lifting unit having a chamber with at least one gas-inlet opening in its wall and an equalization opening in its wall, a gas supply means being connected to the gas inlet opening, the device having a controller connected to the gas supply means for controlling a gas supply rate to the chamber. The chamber has a releasable coupling member for releasably attaching to a load and is connected via a lifting cable to a take up device on the floating structure for lengthening and shortening the lifting cable.

Abstract: A system of the type wherein LNG from a tanker (30) is offloaded to a moored vessel (16), which has a regas unit (36) which heats the LNG to transform it into gaseous hydrocarbons, and which has a pump unit (38) that pumps the gaseous hydrocarbons to a consumer (46) such as an onshore gas distribution facility. The system is constructed to enable more rapid tanker unloading so the tanker is released earlier to sail back to a pickup location. The moored vessel has a thermally insulated LNG storage facility such as LNG tanks (100), with a capacity to store all LNG not regassed during offloading of the tanker. The regas unit has sufficient capacity to regas all LNG received in one tanker load, before the tanker returns with another load of LNG.

Abstract: A system for offloading LNG (liquified natural gas) from a tanker (26) in shallow waters, for regasing, or heating the offloaded LNG to produce gaseous hydrocarbons, or gas, for pressurizing the gas, and for flowing the gas to an onshore station (56), includes a structure that is fixed to the sea floor and projects above the sea surface and aids in mooring the tanker. In one system, the structure that is fixed to the sea floor is a largely cylindrical tower (12) with a mooring yoke (20) rotatably mounted on its upper end. A floating structure (14) such as a barge that weathervanes, has a bow end pivotally connected to a distal end of the yoke, so the barge is held close to the tower but can drift around the tower with changing winds, waves and currents. The tanker is moored to the barge so the barge and tanker form a combination that weathervanes as a combination.

Abstract: A system is described for offloading LNG (liquified natural gas) from a tanker for eventual delivery to an onshore gas distribution station. The system includes a floating structure that floats at the sea surface and that is connected to the tanker so they weathervane together. The floating structure carries a regas unit that heats the LNG to produce gas, and delivers the gas through a riser to an underground cavern that stores the gas. Gas from the cavern is delivered through a seafloor pipeline to an onshore gas distribution station. The regas unit includes water pumps and other equipment that is powered by electricity. The electricity can be obtained from an electric generator on the floating structure, with surplus electricity delivered through a sea floor electric power line that extends along the sea floor to an onshore electricity distribution facility.

Abstract: A barge (14) that stores liquid hydrocarbon (oil) from a producing facility (12) and offloads it perhaps once a month to a shuttle taker (40), is constructed for unmanned operation except during the once-per-month unloading. The barge has a permanent nonadjustable ballast (53, 54, 55) and has a solar powered system for communication with a central center for normal operation and emergency shutdown. The barge avoids a “hotel system” for a permanent crew (up to 50 people) by avoiding seawater ballast tanks, ballast pumps and related systems. The only person-operated equipment is an engine-generator set (142) and pumps (44), to be operated only during offloading for perhaps 3 days every month. The barge is unpowered except by solar energy or batteries, and is left unmanned except during offloading, so only temporary crew quarters are provided. The barge has a tank assembly (57) with rows of tanks connected in series so oil can be loaded and unloaded from the frontmost tank in each row.

Abstract: An offshore hydrocarbon production system includes a spar (34, 52, 214) that floats at the sea surface, a subsea buoy (26, 154, 200, 210) lying under the spar and hanging from it, and one or more risers (20, 174, 220) that extend up to the subsea buoy and are coupled therethrough to the spar. The subsea buoy is initially negatively buoyant to ballast of the spar and keep it upright, but the subsea buoy can be made positively buoyant so the spar can be moved away and a workover vessel (70) moved over the subsea buoy. The subsea buoy can be coupled to the spar by one or more chains (60, 60A) extending between them, and one or more flexible hoses (60) extending between them.

Abstract: An offshore system is described, of the type that includes a turret (20) anchored to the sea floor and connected by at least an upper bearing assembly (34) to the vessel hull (14) so the hull can weathervane about the turret, wherein the upper bearing assembly is of moderate cost and high reliability, is easily maintained, and accommodates vessel hull deformation. The upper bearing assembly includes a circle of bearing devices(202) wherein each device includes a cylinder (224) and piston (226). A source (260) of pressured fluid is applied to the devices to push apart the cylinder and piston to support an upper bearing part (204) of the turret on a lower bearing part (210) of the hull.

Abstract: A fluid swivel of the type that includes a transfer chamber (56) formed between inner and outer main parts (52, 54), is constructed so sand and other particles settling out of the fluid, does not find its way into the lower gap passage (86) and quickly wear out a seal. A second of the main parts has a lower wall with a raised barrier (110) close to the top (122) of the lower gap passage. The first main part lower wall forms a first barrier (112) in the form of a projection that lies closely over the second barrier. The two barriers are closely spaced to form an entrance region (120) leading to the lower gap passage, with the entrance region including an upstream entrance part (132) that extends vertically or at an upward incline to discourage the migration of sand therealong.

Abstract: An offshore system is provided of the type that includes riser pipes (30) extending up from the seafloor (44) to a tall and narrow caisson (12) at the sea surface, with the caisson moored by mooring lines (34) extending to the seafloor and anchored thereat, which minimizes bending of the upper portion of the riser pipes when the caisson drifts in severe weather. Although the caisson has a Ballasted lower end and buoyant upper end to keep its axis (20) vertical, a device is provided for applying a horizontal force (54) to a location along the caisson that is vertically spaced from the upper ends of the mooring lines, to tilt the caisson so the axis of the caisson is parallel to portions (82) of the riser pipes lying immediately below the caisson. In one arrangement, a second set of mooring lines (60) is provided, that have upper ends coupled to second locations (64) along the caisson that are vertically spaced from the upper ends of the first mooring lines.

Abstract: A system is provided for securing a vessel (24) such as a tanker to a moored body (12) that is moored to the sea floor, which enables the vessel to remain secured in more severe weather. In addition to the deployed length (27) of securing line (26) that extends between the moored body and the vessel, applicant stores an additional length (28) of securing line. When large drift forces are applied to the vessel, the vessel is allowed to drift away from the moored body, while a braking apparatus (34) pays out the previously-stored length of securing line, while resisting such pay out by maintaining a high securing line tension such as 300 tons. When the drift force decreases to a predetermined low level such as 60 tons, the braking apparatus draws in the securing line to draw back the vessel towards its quiescent position.

Abstract: An offshore system is described, of the type that includes a turret (20) anchored to the sea floor and connected by at least an upper bearing assembly (34) to the vessel hull (14) so the hull can weathervane about the turret, wherein the upper bearing assembly is of moderate cost and high reliability. In one construction, the upper bearing assembly includes upper and lower slider bearing rings (40, 42) that lie facewise adjacent at an interface (44), with the upper bearing ring fixed to the turret and the lower bearing ring supported on the hull through quantities of elastomeric material (102). The elastomeric material permits slight tilt of the turret upper portion without opening a gap at one side of the interface. The lower bearing ring is divided into segments (112A, 112B), and large turret tilt allows pressured lubricant to escape from only one or a few segments that begins to lift up during turret tilt.

Abstract: A fluid swivel arrangement comprising a vertical stack of fluid swivels mounted on a turret of a weathervaning ship, enables a spare fluid swivel to be provided without requiring an additional pipe and consequent larger diameter of fluid swivels. A pair of fluid swivels (53, 54) are provided, with one serving as a spare to be used in the event of failure of the other. A single pipe (94) extends through holes (120) in the swivels and is coupled to the inlet ports (90, 92) of both swivels, so it can direct fluid into either one. A means for controlling flow, enables the flow to be switched to either fluid swivel. The means for controlling flow can include a plug (140) for insertion into the inlet port of one of the swivels, to block the inflow of fluid thereat. The means for controlling flow can also include a valve (130) lying along the pipe between the upper and lower fluid swivels, so when the valve is closed fluid flows only to the lower fluid swivel.

Abstract: An offshore fluid transfer system (10) is provided, of the type that includes a riser (32) having an upper end (34) connected through a universal joint (36) to a turret (22) on a vessel and having a lower end (36) anchored by catenary chains (40), and that also includes hoses (70, 71) extending from a base (50, 58) on the seafloor to the turret on the vessel, which avoids the need for a complicated hose structure to pass fluid across the universal joint. A fluid coupling (73) near the bottom of the turret, which is widely spaced from the universal joint, connects to a hose that extends from the fluid coupling in a sinuous path down to the seafloor base. The long length of hose, enables it to bend when the vessel drifts, to avoid excessive hose tension or riser contact during such vessel drift. A riser connector (102) can be operated to disconnect the riser from the turret so the riser can sink. The fluid coupling can include a fluid connector (100) which can separately disconnect the hose from the turret.

Abstract: A bearing assembly that mounts the lower portion of a rotatable large (at least 4 meters diameter) turret in a moonpool near the center of a vessel, avoids damage resulting from turret and/or vessel deformation in heavy seas, while facilitating initial alignment. The turret (10) holds a substantially continuous bearing ring (44) while a hull part (42) holds a plurality of circumferentially-spaced segment structures (46) that have segment bearings (50) engaged with the bearing ring. Each segment structure includes a base (56), and an elastic body (60) that supports the bearing segment while allowing it to move radially or tilt. A deflection limiter (80) can limit deformation of the elastic body. Each segment structure can include an adjustment device (62) that adjusts the position of the bearing segment during setup.

Abstract: A tension leg platform system includes a relatively small platform (12, FIG. 3 ) and relatively low capacity tendons (16), despite providing sufficient tension to risers (34) that carry hydrocarbons from seafloor wells to the platform. With the platform floating at the sea surface and held in position by the tendons, seafloor wells can be connected through risers to a side of the platform, with the tension of each riser compensated by adding buoyancy to the corresponding side of the platform, as by using pressured air (at 100) to blow water out of a platform compartment (94).

Abstract: An offshore production system of the type that includes a TLP (tension leg platform) (12) and a derrick vessel (14) which moves to the TLP platform (16) whenever the derrick is required. The vessel carries fastener assemblies (131) that rigidly fix the vessel to the platform so they move vertically and horizontally as a single unit, which avoids any need to separately anchor the vessel and which facilitates operation of the derrick in more adverse weather. The vessel preferably has thruster equipment (88) which not only allows it to self-propel itself to the platform, but which also allows the vessel to propel itself and the platform sidewardly, to avoid drift of the platform during drilling. The vessel includes a vessel deck (70) which lies above the platform and a pair of vessel sides (72, 74) with pontoons (76, 78), that lie on opposite sides of the platform.

Abstract: A turret that is rotatably mounted on a vessel and connected to risers extending down to sea floor wells, is constructed so the turret is of moderate diameter to enable the use of a moderate size bearing and moderate weight turret, while providing room around the terminations of the upper ends of the risers. The risers (46A, 46G, FIG. 3 ) extend through tubes (62, 70, 72) which are oriented at an angle to the turret axis (22), so the lower ends of the tubes lie on large diameter circles to be considerably spaced apart, while the upper ends of the tubes are closer together to fit within the inside of the moderate sized bearing (60). The upper ends of the risers may be terminated at a plurality of different levels (90, 92, 94) within the turret to provide room around each termination.

Abstract: An arrangement is described for mounting a turret (18, FIG. 3) on the outer ends of beams, or mounts, whose inner ends are supported by a vessel hull (14) that can weathervane about the turret. An upper bearing (42) is supported on a largely rigid upper mount (30), by a resiliently deflectable support structure (50) that includes a plurality of elastomeric shear pads (52). Each shear pad subtends an angle (B, FIG. 5) of no more than 20.degree. about a common point (26) along the rotatable axis of the turret. This allows a shear pad to use flat rubber sheets instead of spherically curved sheets, as well as avoiding excess stiffness. The support structure includes six posts (54) extending radially from the common point along the turret axis, each post having a gap where a shear pad is mounted, with the area around each shear pad being open to facilitate replacement of a shear pad.

Abstract: An offshore fluid transfer system is described, for transferring fluid between stations (12, 14, FIG. 1) that may be many kilometers apart and lie in deep water, which avoids the need for making fluid connections at great underwater depths. A buoy station (14) includes a buoy (40) anchored to the seafloor to lie a moderate distance below the sea surface, and coupled through a flexible hose (46) to a turret (52) that is attached to a weathervaning vessel (30) and that is anchored to the seafloor. A major conduit portion (34) which extends between the first station and the buoy, includes a long pipeline of series-connected steel pipes that extends along the seafloor to near the buoy station, with an end portion (32) of the pipeline extending in a J-curve and in a primarily upward direction to the underwater buoy.