Abstract: The floating structure has limited heave oscillations. A long member has a lower end coupled to the seabed. An extensible tensioner is coupled between a platform deck and the upper end of the long member. The tensioner suspends the upper end of said long member and applies a predetermined tension thereto. The tensioner includes anti-heave force-exerting means for exerting downward-acting forces on the floating structure.

Abstract: A floating/tensioned production system for use in deepwater drilling and production operations generally combining a relatively small tension leg platform with a semisubmersible platform. The semisubmersible platform is provided with a working deck supported above the water surface so that an air gap exists between the working deck and the water surface. The tension leg platform provides a heave-restrained production deck for near-surface wellhead equipment. The production deck is supported above the drill site but beneath the water surface by buoyancy members and held in place by one or more tethers. Most other drilling and production equipment is located on the semisubmersible working deck. A caisson, surrounding the production deck, is used to provide a substantially dry working area. In one embodiment, the caisson is retractably attached to the production deck.

Abstract: The floating structure has a structural frame and a long member which has a lower end anchored to the seabed. The structural frame has limited heave motion relative to the long member. An extensible tensioner is between the frame and the long member. Mechanical brakes apply braking forces against the long member only when the floating structure heaves up. The brakes are inactive when the floating structure heaves down.

Abstract: A resilient ball joint support including two plates movable with respect to each other and connected together by at least one ball joint, the transmission of a load between the plates being provided, partly through at least one cushion formed of at least one sealed envelope confining at least one fluid which is pressurized by the action of the load and partly by at least one ball joint centering the plates with respect to each other.

Abstract: A dynamic load compensation system for supporting a crown block comprises:(a) first structure including the crown block to receive applied loading, and subject to displacement generally in the direction of load exertion,(b) a base frame spaced from that structure, and(c) means including groups of fluid actuator members pivotally connected to the base frame and to that structure for supporting same on the base frame, said members acting to resist such displacement of the structure characterized in that said base frame may move relatively toward and away from the structure while said loading continues to be applied to the structure,(d) the actuators in each group extending in parallel relation.A sheave is typically offset from the crown block to control a line or lines leading to the crown block; and two pivoting links connect the sheave with the base frame and block.This application is a continuation-in-part of my prior application Ser. No. 35,784, filed Apr.

Abstract: A dynamic load compensation system comprises:(a) first structure to receive applied loading, and subject to displacement generally in the direction of load exertion,(b) a base speed from said structure, and(c) means including pairs of generally parallel fluid actuator members pivotally connected to said base and to said structure for supporting said structure on the base, said members acting to resist said displacement of said structure characterized in that said base may move relatively toward and away from said structure while said loading continues to be applied to said structure.

Abstract: A heave compensated stabbing and landing tool and method for use on a floating platform comprises a tool attached to a heave compensator on the floating platform. The tool, attached at one end to a taut line anchored to the seabed, includes means for gripping, raising and lowering a tubing string. The tool is attached to the heave compensator, which is raised to tighten the anchor line and substantially eliminate relative motion between the end of the tubing string and the seabed. The tool grips the tubing string and lowers it to the seabed in a controlled manner.

Abstract: A resilient ball joint support is provided including two plates movable with respect to each other and connected together by at least one ball joint, the transmission of a load between said plates being provided, partly through at least one cushion formed of at least one sealed envelope confining at least one fluid which is pressurized by the action of said load and partly by at least one ball joint centering said plates with respect to each other.

Abstract: A single point mooring system e.g. for an offshore oil or gas production system, consists of a rotary turret 6 provided in a floating structure 1 e.g. a tanker to which the turret is retrofitted. The turret 6 comprises a skirt portion 11 on the underside of the tanker and an upwardly extending cylindrical chimney portion 12. The turret is connected to the seabed by mooring lines 3 and risers 6 supply oil to the tanker for temporary storage. The mooring lines 3 comprise segmented chains that are hauled by winches 20 and secured by stoppers 18, 19 in the skirt 11. The turret is rotatably suspended from the upper end of the chimney portion 12 by an upper main bearing comprising rotary rings 40, 41, which is interchangeable while the mooring system is in service. Annularly disposed lower bearings 26 are arranged to resist radial loads on the chimney portion but to be compliant to axial turret loads, to accommodate forces and moments applied to the turret and the tanker by wave action.

Abstract: A floating drilling platform having dual work stations is disclosed for performing deep sea drilling and/or hydrocarbon production operations. The structure of the platform is designed to accommodate replaceable modules which facilitate the installation and removal of either a drilling derrick or production equipment. Thus, during the drilling phase of a reservoir's development, the platform may be outfitted with dual drilling derricks while at later times the platform may be outfitted with a drilling derrick and a full production facility. Various expedients are available to permit the equipment of one work station to be used in conjunction with the equipment of one other. Simultaneous management of dual conductors is enabled by a dual riser management system which models in real time riser behavior under varying environmental and other operational conditions. The dual riser management system includes a riser analysis subsystem, a mooring analysis subsystem and a vessel stability analysis subsystem.

Abstract: A tendon installation for anchoring a semisubmersible platform to a sea bed foundation, wherein said tendons are tensioned by the updrift of the platform. The tendons are prefabricated in dimensions adpated to the depth of the sea bed foundation, expected tension load and in order to be substantially weightless in water. The tendons are connected in groups at each of their ends at a distance corresponding to the distance between anchoring points in the foundation and the platform respectively. The groups of tendons are towed out to the anchoring site and they are positioned vertically above the foundation. The tendons are fastened to the anchoring points in the foundation. The platform is positioned above the groups of tendons and connected to these via wire ropes. The platform is ballasted down onto the tendons under guidance by said wire ropes. The upper ends of the tendons are mounted internally in the legs of the platform.

Abstract: A system for supporting one end of a riser or other elongate element from a marine structure. In the preferred embodiment, a plurality of gas springs are symmetrically disposed about the upper end of a riser. The axis of compression of each gas spring is parallel to the axis of the riser. One end of each gas spring is secured to the riser and the other end of each gas spring is secured to the marine structure. Relative motion between the riser and marine structure along the riser axis is accommodated by contraction or extension of the gas springs. A gas reservoir can be provided to reduce pressure changes as the gas springs extend and contract. This reduces changes in the loading applied to the riser as the marine structure moves relative to the ocean bottom.

Abstract: A tensioner unit (12) comprising an inner cylinder (22), filled partially with hydraulic fluid, with a piston (26) and piston rod (28) reciprocal therein (sometimes referred to as a hydraulic cylinder) surrounded by a cylindrical chamber (40) (sometimes referred to as an accumulator) for hydraulic fluid and gas. The gas in accumulator (40) is pressurized to maintain the hydraulic fluid under pressure against the piston (26) placing the piston rod (28) under tension to provide the necessary tension force on a marine riser (14) and to compensate for the rise and fall of a floating platform. This is a self-contained integral unit with one end of the piston rod (28) connected to the riser (14), and the other end connected to a frame (16) supported on a platform of a TLP. A plurality of such tensioner units (12) on this frame (16) and connected to said riser (14) form a complete riser tensioner (10) without external accumulators.

Abstract: Several embodiments of a marine riser tensioner (10, 100, 200, 300) are disclosed for use in tensioning a marine riser (12) on a tension leg platform (14) by the use of elastomeric elements. In one embodiment, a plurality of elastomeric pads (60) are placed in pad shear to provide tension to the marine riser. In another embodiment, elastomeric disks (124) are placed in torsional shear to provide the tension to the marine riser. In other embodiments (200, 300) elastomeric cones (208) deform in ring shear.

Abstract: A bearing structure which may, for example, be used for rotatable mounting of a turret or a rig (11) on the hull (14) of a vessel comprises a first annular bearing surface which is supported by the vessel hull (14), and which may be substantially plane or cylindrical. A second annular bearing surface which is in engagement with and supported by the first bearing surface is formed on the turret or rig (11). The hull (14) of the vessel is exposed to heavy forces caused by wind and waves, and such forces may cause deformations of the hull and consequently of said first bearing surface. In order to compensate for such deformations, the first bearing surface is divided into sections, and position control means, such as mechanical, pneumatic, or hydraulic spring means, are provided for maintaining all of the bearing surface sections in abutting engagement with said second bearing surface formed on the turret or rig (11).

Abstract: An upper marine riser package (10/10A) comprising a diverter (D) for diverting uncontrolled gas and return drilling mud therethrough, a flexible joint FJ for allowing tilting motion between a vessel and a riser string (RS), a self-tensioning slip joint (SJ) and riser rotation bearing joint (RB) suspended below said vessel (V) to compensate for vertical motion between a subsea well (W) and a floating vessel (V). The upper marine riser package (10/10A) is sized to be run through a confined opening such as a riser handling spider (HS) and rotary table (RT) and to be suspended and operated below the deck of the vessel (V). The upper marine riser package can be used to eliminate the conventional riser tensioners normally above the platform and can be used in combination with such conventional riser tensioners normally above the platform for deeper and deeper drilling opertion.

Abstract: A system and method for attaching and removing equipment from a subsea wellhead in which equipment is lowered and raised on a flexible riser pipe, cables extend from the equipment to the wellhead and are winched in and out to control movement of the equipment adjacent the wellhead. While the cables are being winched in or out, the cables are maintained in tension by the cable reel or a motion compensator, between the equipment and riser pipe, permits the riser pipe to reciprocate vertically with the vessel in response to wave action, while the equipment is insulated from this action during engagement and disengagement with the wellhead. The equipment may include a guide frame, which may be made in two pieces, so that the upper section of the guide frame together with a riser pipe connector, may be released from the remainder of the frame and connector and lifted off by the riser pipe or by buoyancy means.

Abstract: The present invention provides a vessel mounted mooring system and a method for its installation. The method involves the construction of a vertical well in the vessel extending from the deck through the bottom plates of the vessel. A lower bearing ring which circumscribes the well is connected to the underside of the bottom plates. A lower turret unit is laterally guided by the lower bearing ring and is restrained against uplift forces by the lower bearing ring. A middle turret unit is placed into the well and connected to the lower turret unit. An upper bearing ring which circumscribes the well is mounted to the deck. The upper turret unit is connected to the middle turret unit whereupon the weight of the assembly of the upper, middle and lower turret units is supported by the upper turret unit and is guided by the upper bearing ring.

Abstract: The present invention provides a vessel mounted mooring system and a method for its installation. The method involves the construction of a vertical well in the vessel extending from the deck to the bottom plates. A lower bearing ring which circumscribes the well is connected to the underside of the bottom plates and extends beyond the keel. A lower turret unit is supported substantially within the bearing ring. A middle turret unit is placed into the well and connected to the lower turret unit. An upper bearing ring which circumscribes the well is mounted to the deck. An upper turret unit is connected to the middle turret unit whereupon the assembly of the upper, middle and lower turret units is supported and guided by the upper bearing ring and further guided by the lower bearing ring.

Abstract: A slip joint for use in a well string and having a removable torque transmitting key. The slip joint includes an outer female mandrel having a central opening therethrough in which is slidingly positioned a male mandrel, also defining a central opening therethrough. In one embodiment, the male mandrel defines at least one longitudinal slot therein and the female mandrel defines a transverse opening therethrough adjacent the slot. The torque transmitting key is positioned in the transverse opening and extends into the slot. In the second embodiment, the inner mandrel includes a flat surface thereon and the outer mandrel has a longitudinal slot therein adjacent the flat surface. The key includes a ring portion having a flat surface therein engageable with a flat surface on the male mandrel and a lug portion extending from the ring portion into the slot.

Abstract: An apparatus provides a swivelless connection of first and second fixed positions on respective first and second structures. The structures are relatively rotatable about a common axis, through a length of flexible conduit defined by first and second space portions thereof respectively connected to the first and second fixed positions and predetermined in accordance with the extent of relative rotation to be accommodated while continuously maintaining the connection.

Abstract: A dynamic load compensation system comprises:(a) a first element to receive predetermined applied loading, and a base spaced longitudinally from that element,(b) structure including articulated members supporting the first element on the base and acting to resist displacement thereof characterized in that the base may move relatively toward and away from the first element while such predetermined loading is applied to the first element,(c) certain of the members extending longitudinally and laterally leftwardly, and others of the members extending longitudinally and laterally rightwardly,(d) first connections including links pivotally interconnecting the certain members, and(e) second connections including links pivotally interconnecting the other members.

Abstract: A circular guide table is provided for a marine production riser comprising an opening for the central tube having a ball joint allowing angular movement of the tube in any direction with respect to the table and two radial arms offset from each other by an angle close to 90.degree. fixed to the table and whose ends each support a sliding device, such as a roller carriage capable of sliding along vertical rails fixed to the platform. The table is formed from an inner collar in the form of a hub to which are fixed spokes between which the peripheral production stringers pass, the opposite ends of the spokes being joined together by an external collar provided with radial arms.

Abstract: Method and apparatus for use in drilling a well from a floating vessel by means of a riser which connects the vessel's drilling equipment to a wellhead assembly adjacent the ocean floor. Braking apparatus is provided which is capable of arresting the vertical motions of the drilling riser and of securing the upper end of the riser to the vessel whenever the riser is disconnected from the wellhead.

Abstract: Apparatus for use in drilling a well from a floating vessel by means of a riser which connects the vessel's drilling equipment to a wellhead assembly adjacent the ocean floor. The riser is capable of being disconnected from the wellhead assembly and having the motion of its upper end arrested and subsequently secured to the vessel. The present riser braking clamp apparatus comprises braking elements integrally carried by the telescoping joint located at the upper end of the riser. Actuation of these braking elements prevents further telescopic movement of the telescopic joint, thereby preventing movement of the riser upper elements relative to the vessel.

Abstract: A riser tensioning and recoil system for a riser extended between a floating platform and a submerged riser base comprises at least one riser tensioning cable which is operatively connected to the riser and to a collar which is slidably arranged around the riser. To establish a controlled recoil of the riser, stop means are provided that restrict axial movement of the collar relative to the riser after the riser has been lifted from the riser base, thereby enabling the collar to gradually decelerate the vertical movement of the riser.

Abstract: This invention relates to a joint for risers, and particularly to a telescopic joint suitable for expandably connecting composite-pipe type riser pipes provided internally with tubing pipes. Its structural features reside in that connectors adapted to connect risers in up-and-down relationship are slidably engaged with each other and air cylinders capable of cancelling volume changes of the engaged portions, which volume changes occur due to expansion and contraction movements of the connectors, are communicated to the spacing of the engaged portions, and hydraulic cylinders adapted to cancel volume changes of the engaged portions of an internally-threaded nose portion and an externally-threaded nose portion, which engaged portions serve to communicate the upper and lower tubing pipes to each other, is communicated with the spacing of the engaged portions of the nose portions.

Abstract: Apparatus for use in drilling a well from a floating vessel by means of a riser, which connects the vessel's drilling equipment to a wellhead assembly adjacent to the ocean floor. The riser moves substantially vertically in relation to the vessel, as the vessel responds to wave action. The present riser position indication apparatus is comprised of a load cell and a chain attached beneath the load cell. Movement of the riser relative to the vessel alters the length of chain suspended from the load cell, thereby altering the signal from the cell. The signal can be subsequently calibrated to represent riser position.

Abstract: A system of liason between an underwater wellhead for the production of hydrocarbons from underwater formations to a surface support. The system includes at least one flexible conduit (4) connected between the wellhead (2) and the surface support (1). Each flexible conduit is equipped at its lower end with means to limit the radius of bending or deflection and is connected vertically to the wellhead. Each conduit can be pulled or led into at least a first configuration (4a, 4'a, 4"a) in which the conduit is generally relaxed and non-tensioned, for the flow of hydrocarbons to the surface support, and at least a second configuration (4b), in which the conduit is at least partly tensioned, and sufficiently straight and upright that tools can be lowered to descend by gravity from the support surface to the well, for working of the well.

Abstract: Method and apparatus for use in drilling a well from a floating vessel by means of a riser, which connects the vessels drilling equipment to a wellhead assembly adjacent the ocean floor. The riser is capable of being disconnected from the wellhead assembly, and having its upper end locked to the vessel. The present riser locking apparatus is made up of selectively-positionable resiliently-moveable locking beams adapted to be remotely actuated to lock the upper elements of the riser to the vessel, thereby preventing lateral or vertical movement of the riser relative to the vessel.

Abstract: Apparatus and method for use in drilling a well from a floating vessel by means of a riser, which connects the vessels drilling equipment to a wellhead assembly adjacent the ocean floor. The riser is capable of being disconnected from the wellhead assembly, and having its upper elements locked to the vessel. This allows the riser to be suspended from the floating vessel, or permits maintenance of the normal riser motion-compensating and tensioning equipment. Riser locking apparatus is employed which comprises selectively positionable moveable locking beams adapted to be remotely actuated to lock the upper elements of the riser to the vessel, thereby preventing lateral or vertical movement of the riser relative to the vessel after the lower end thereof has been disconnected from the wellhead assembly.

Abstract: The invention pertains to tensioners for maintaining a load between two relatively movable structures, such as an offshore drill ship or the like and a riser pipe. First and second tensioner bodies are mounted for relative reciprocation, and are further functionally interconnected with the first and second offshore structures respectively. Relative movement of the offshore structures tends to cause corresponding relative reciprocation of the tensioner bodies. A force is applied between the tensioner bodies tending to reciprocate them in a first directional mode and thereby supporting the offshore riser pipe with respect to the offshore support structure. A balancing chamber cooperative between the tensioner bodies communicates with a source of pressurized fluid for resisting reciprocation of the tensioner bodies in the first directional mode, but includes an outlet for egress of the pressurized fluid to permit such reciprocation under controlled conditions.

Abstract: Conductor pipes on an offshore drilling and production platform pass through openings in the decks of the platform. The openings are to be sealed off to prevent spreading of hot and/or noxious fluids from one deck to another. The sealing means consists of two annular elements arranged around a conductor and connected to the conductor and the deck, respectively, thereby forming an annular trough in which one of the elements protrudes. The trough is filled with a flexible substance, such as a silicone foam.

Abstract: A motion compensator for disposition between an offshore support structure and an offshore well structure movable with respect thereto comprises a compensator assembly interconnected with the support structure and the well structure such that relative movement between said structures will cause movement within the compensator assembly, and a position indicator including a cam assembly for measuring the relative movement within the compensator assembly, and a transducer operatively associated with the cam assembly for translating its measurements into a signal.

Abstract: In underwater well installations of the type in which a template or like rigid base structure at the floor of a body of water defines a well opening, and an outer well member such as a suspension joint secured in the borehole projects upwardly within the well opening, the outer well member is connected to the template by a structure which restrains the outer well member from moving laterally relative to the base structure until the force tending to cause such lateral movement exceeds a predetermined large value, after which point the connection serves as a lost motion connection allowing the outer well member to move laterally through a limited excursion relative to the template.

Abstract: A flexible connection apparatus is disclosed for accommodating relative movement between a compliant offshore structure and the sea floor. The compliant offshore structure supports a fluid-carrying system which conveys fluids between the sea floor and the structure. The fluid-carrying system includes a riser and a helical flowline. The lower end of the riser is connected to the sea floor. The first end of the helical flowline is connected to the upper end of the riser and the second end of the helical flowline is connected to the structure. As the compliant offshore structure is displaced from its vertical equilibrium position due to loading forces induced by wind, waves, and ocean currents, the helical flowline elastically flexes through torsional deflection to accommodate such movement. In a preferred embodiment of the apparatus, a wellhead is connected between the riser and the helical flowline such that the centerline of the helical flowline is substantially vertical.

Abstract: The invention pertains to motion compensators and compensator systems, particularly adapted for disposition between an offshore platform and a riser or conductor pipe. Each compensator includes a cylinder with a piston reciprocably mounted therein, the piston rod protruding from one end of the cylinder. That one end of the cylinder is directed toward and connected to either the platform or the riser pipe, with its other end being directed toward the other of those two bodies. Link rods are independently connected to the protruding part of the piston rod and extend longitudinally toward said other end of the cylinder for connection to said other of the two bodies. A compressible fluid is disposed between the piston and said other end of the cylinder to resist movement of the piston toward said other end and thereby resist movement of the platform and the riser pipe away from each other.

Abstract: A self standing marine riser is provided which comprises a base, a riser column, a flexible joint between the base and the riser column, and means for providing a loose coupling between the top of the riser column and a vessel, rig or platform on the surface above the location of the riser. The riser column comprises an upper column section which includes at least one buoyancy chamber, and a lower, relatively slender column section. The riser includes, or is adapted to support, at least one conduit for the conveyance of a fluid (e.g. oil or gas) or a control line. The buoyancy provided by the upper section of the riser column is preferably variable, and this facilitates the connection and use of the riser. The riser may be used for drilling operations or for production operations. By employing a riser in accordance with the invention, it is not necessary to use large riser tensions in order to maintain the position and structural integrity of the riser in deep water and rough weather.

Abstract: A rotary transfer subsystem is described for transferring production fluids, electrical power, hydraulic power, and control signals across a rotating interface between an offshore process vessel and a flowline bundle of service hoses and high-pressure hoses which are connected to a deepwater production riser system. Tensioning devices are also described for maintaining a selected tension on terminal hoses between the interface and the vessel while the vessel weathervanes during maintenance of position in a watch circle above the riser system. The subsystem and the tensioning devices are mounted on the vessel which is equipped with a powered turret within a circular moonpool and is capable of performing most subsea service functions on the riser system without major equipment support.

Abstract: A riser tensioner safety system for preventing damage to a floating drilling vessel in a broken cable event or an emergency disconnect of the riser is disclosed. The system uses standard pneumatic/hydraulic tensioning devices together with a safety valve which is installed in the hydraulic fluid supply line to the tensioning device. The valve is held open by tension in the riser tensioner lines. If tension drops below a predetermined level due to a broken cable event or an emergency disconnect of the riser, the valve closes rapidly preventing acceleration of the tensioner piston.

Abstract: A telescopic joint inner tube retainer is provided for holding the joint upper tube to a cross over support conduit suspended by a ball and socket conduit connection to a diverter type coupling to a floating vessel or overhead platform wherein retainer has a split internally threaded locking ring engaged about a mating thread on an upper exterior portion of the telescopic joint upper tube, a solid support ring landed upwardly about the split locking ring and means for drawing the solid ring tightly upwardly toward the support conduit with the split locking ring therebetween to suspend the joint upper tube from the support conduit in a manner which can be easily disengaged even if the threaded engagement between the locking ring ad joint upper tube would not otherwise be releasable through relative turning movement of the locking ring and joint upper tube.

Abstract: A motion compensator for disposition between an offshore support and an offshore well string or the like movable with respect to the support comprises first and second compensator bodies interconnected with the support and the well string such that relative movement between the support and well string causes relative movement between the compensator bodies. The compensator bodies are further interconnected with each other for relative movement in generally vertical directional modes. A compressible fluid or the like is associated with the compensator bodies for resiliently resisting relative movement therebetween in a first directional mode. A position indicator associated with the compensator bodies comprises a flexible vessel having one end connected to one of the compensator bodies and the other end connected to the other compensator body generally below the one end.

Abstract: A support and connecting system for a multiline riser which joins a floating platform to a subsea well is shown including a support housing which mounts upon the floating platform for disconnectably mounting a termination housing to which a plurality of lines are connected. The termination housing is also connected to the platform by a cable tensioning system which adjusts the tension within its connecting cables. A termination head fits within the termination housing and connects, through a termination riser adapter, to the uppermost riser of a riser run that communicates between the platform and the subsea well. The arrangement permits the riser run to engage the floating platform during assembly and recovery of the risers. In the event of a storm or other need for emergency disconnection, the riser run may be withdrawn from the termination housing and hung off or recoved without disconnecting the lines.

Abstract: A drilling riser between a subsea wellhead and a floating platform has a slip joint in its upper end. A chamber is formed within the slip joint and supplied fluid pressure to develop a tensioning force on the upper end of the riser as the floating platform cycles vertically under the influence of heave and tidal forces.

Abstract: Equipment which extends from a floating structure towards the ocean floor therebelow is supported on the floating structure by a device which includes at least two hydraulic cylinders which are arranged between the floating structure and the equipment, the hydraulic cylinders being connected to a source of hydraulic pressure fluid, and a valve apparatus which is connected via a first conduit to each hydraulic cylinder on the piston rod side of its piston and via a second conduit to each hydraulic cylinder on the opposite side of its piston. The valve apparatus connects the first and second conduits for each hydraulic cylinder under normal conditions, but under deviant pressure conditions in one hydraulic cylinder breaks the connection between the first and second conduits of the other hydraulic cylinders and connects their first conduits with the first and second conduits of the deviant hydraulic cylinder.

Abstract: A discharge manifold system is provided for connecting a pressurized fluid discharge from a floating vessel to an offshore well. A floating buoy is anchored at a distance away from the offshore platform. A first manifold is located on the floating buoy and includes an inlet and first and second outlets. A second manifold is located on the production platform adjacent the offshore well and includes first and second inlets and an outlet which is connected to the offshore well. First and second valves are connected to the outlets of the first manifold. Third and fourth valves are connected to the inlets of the second manifold. A first flexible intermediate conduit is connected between the first and third valves and a second flexible intermediate conduit is connected between the second and fourth valves.

Abstract: A method is provided for cementing an annular cavity between a subsea well casing and a borehole from a floating vessel. A drill string is run into the casing. An opening positioner attached to the drill string is engaged with a valve in the casing. The drill string is lifted to open the valve. The drill string is positioned to align an isolation packer with the casing valve. An anchor attached to the drill string is set to provide sufficient resistance between the drill string and the casing to operate a motion compensator on the floating vessel. A cement slurry is then pumped into the drill string, out the isolation packer, through the open casing valve and into the annular cavity between the casing and the well bore-hole.

Abstract: An apparatus is provided for cementing an oil well borehole from a floating vessel. A sliding sleeve cementing valve is adapted to be interconnected with a casing string. A drill string to be lowered into the casing string includes a drill pipe, an opening positioner connected to the drill pipe for opening the cementing valve, an anchor connected to the opening positioner to provide sufficient resistance between the drill string and casing string to operate a motion compensator on the floating vessel, and an isolation packer connected to the anchor.

Abstract: A tensioner system is disclosed for applying tension to a riser pipe extending between a floating vessel and the sea bottom. The tensioner comprises a guide means fixed onto the floating vessel for restraining guide members from substantial lateral movement relative to the vessel while permitting relative vertical motion of the guide members, means on the vessel for applying vertical tension to the guide members and suitable means for connecting the guide members to the riser such that the vertical tension applied to the guide members is substantially the same as the vertical tension applied to the riser.

Abstract: A marine structure for guiding a plurality of ducts from deeper to higher submerged devices such as an oil well at the sea bottom and a production or storage station, respectively. The apparatus provided in accordance with the present invention compensates for relative movement between the higher and lower device by providing a rigid column having pivots at both the higher and lower devices. A plurality of ducts are attached to the rigid column and are connected to a corresponding plurality of higher ducts by similar pivot means. The higher ducts are arranged at the higher device so as to allow for relative longitudinal movement of the higher ducts with respect to the higher device.