Abstract: In the progressive forming and laying of an undersea pipeline the welded joints between the ends of pipes pre-coated with a corrosion protection coating and an outer concrete weighting coating are protected by a mastic coating applied by clamping a mould around the pipeline joint to form a cavity between the joint and the mould, filling the cavity with mastic by forcing into it under pressure a charge of mastic at a temperature of not more than 70.degree. C., releasing the pressure and opening and removing the mould. The mastic coating is applied up to the level of the concrete coating adjacent the joint.

Abstract: An apparatus for securing a flowline to a structure near the seabed comprises a vertically oriented guide funnel placed atop a guide tube that is provided with a helical shoulder cooperating with an alignment key mounted on the flowline. During installation the flowline is stabbed into the guide funnel and guide tube thereby causing the alignment key to slide along the shoulder until a pair of hinge pins mounted on the flowline have entered into a pair of slots in the wall of the guide tube. Subsequently the flowline is hinged down to a horizontal position.

Abstract: The invention provides a method of assembling and installing pipes comprising disposing at least one cable between a first station and a second station; attaching and clamping a first pipe to the cable at or adjacent one of said stations; moving the pipe away from said one station with the cable; connecting a second pipe to the first pipe and attaching and clamping the second pipe to the cable at or adjacent said one station; repeating the connecting, attaching and clamping operation to provide an elongate connected sequence of pipes attached to and clamped to the cable; and drawing the cable away from said one station towards the second station to move the sequence of pipes into its desired position between the first and second stations.

Abstract: A guideline connector (30) capable of being inserted over the top of a guide post (12) and has releasable locking means (40) which responds to the guide post contour to resiliently lock the connector onto the guide post profile (22). The locking means includes means (82, 84) for inactivating the locking means to free the connector of the guide post (12) and for automatically resetting (80, 86) (reactivating) the locking means (40) for further use. The locking means is functionally responsive to the outer contour of the guide post (12).

Abstract: A riser system having at least one riser with a J-shaped configuration for transporting hydrocarbon fluids from a subsea manifold or wellheads to a surface vessel. The riser has a horizontal section, an upright section, and a sag bend section interconnecting the horizontal and upright sections. The horizontal section is connected at one end to the subsea manifold and extends along and in frictional engagement with the seabed away from the manifold. The upright section has a vertical end part coupled to the surface vessel. The vessel can remain in position with dynamic thrusters or mooring lines, and the vessel remains on station applying horizontal pull to the riser while heading into the prevailing sea and as hydrocarbon fluids are transported from the manifold through the riser to the surface vessel. The horizontal pull on the riser due to the surface vessel is taken up by friction forces between the horizontal section of the riser and the seabed.

Abstract: A pipe initiation anchor forming a fixed anchor point for use in laying underwater pipelines comprises a ground engaging member in the form of a ballast box or a ground pile, a socket for receiving an end portion of a pipeline, and a locking member for retaining the end portion of the pipeline within the socket. The locking member is pivotally mounted on the anchor and is biased towards a locking position by a counterbalance weight.

Abstract: A method and apparatus are provided for reducing the force required to move a pipe through a J-tube attached to an offshore platform. The J-tube is provided with at least two spaced-apart sections and at least the pipe and/or one section is oscillated as the pipe is moved through the J-tube, thereby reducing the force required to move the pipe.

Abstract: Apparatus for forming a grouting member, for example, a grouted pile, in deep water comprises a female coupling member for connection to a male coupling member located on the sea bed, a conical guide for guiding the male coupling member into engagement with the female coupling member, a rotatable locking pin having an arcute recess portion, operable by a remotely operated underwater vehicle, for retaining the male coupling member in engagement with the female coupling member, and a connector for connecting the female coupling member to a source of grouting material.

Abstract: Apparatus for connecting portions of subsea flow conduits includes a stab member with a body and having a bore therethrough, one end of which exits from the stab body through a side port. A stab receptacle includes a bore for receiving the stab body, and a flow bore intersecting the receiving bore and leading to the exterior of the receptacle. The side port communciates with the receptacle flow bore when the stab member is landed in the receiving bore. Seals above and below the side port seal the receiving bore above and below the intersection of the receptacle flow bore and receiving bore. The cross-sectional areas of the seals exposed to internal fluid pressure are substantially equal, resulting in zero blow-apart force on the stab connection. Alternatively, the lower seal can have a larger exposed cross-sectional area than the upper seal, resulting in a net force tending to hold the connection teogether.

Abstract: An offshore oil platform (1) is provided with an improved riser handling system for making a subsea connection of a riser (6) to the platform, without the need for divers or boats to move the riser into position. A first coupling part (7) on the riser (6) is releasably coupled to a second coupling part (8) which in turn is releasably connected to a third coupling part (9) mounted in a submerged position on the platform. The second coupling part (8) is used as a guide to position the riser. The part (8) is coupled to cables (12,14) wound by winches (13,15). In use the riser can be released from the position shown in FIG. 1 to fall to the sea bed. To reconnect the riser, it is raised by davit (16) onto a platform (17), where the second coupling part (8) is fitted onto the part (7) on the riser. The cables (12,14), are then adjusted to draw the second coupling part (8) and hence the riser to the third coupling part (9) for connection therewith.

Abstract: A subsea connection assembly including a connection box having an open top and provided with a plurality of pipe segments coupled thereto, each pipe segment having an outlet end near the open top of the connection box. The pipe segments have their inlet ends coupled to a manifold assembly having connections to subsea wells. Guide wires are attached to the connection box for guiding a frame downwardly from a floating vessel or platform on the surface of the sea, the frame being operable to carry the lower ends of a plurality of fluid conductors downwardly to the connection box so that such lower ends can become connected to the outlet ends of the pipe segments.

Abstract: A template (26) attached to an anchor pile (12) supports a pull-in tool receptacle (28) at a predetermined location with respect to the anchor pile. The end of the pipe to be connected includes a riser mandrel (16), the lock down connector (20), and a buoyancy module (52). A bridle (42) is temporarily connected (44, 48, 50) to the end of the pipe with the pull-in cable threaded through a pull-in tool (30) and attached to the bridle.The pull-in tool is locked (32) in the frame, and engages and secures alignment pins (40) attached to the bridle when the line has been pulled in. The pipe end is moved (59) into locked engagement with the anchor pile, the bridle (42) disconnected from the pipe end, and thereafter retrieved to the surface with the pull-in tool (30).

Abstract: A method and apparatus are provided for reducing the force required to move a pipe through a J-tube riser attached to an offshore platform. The J-tube riser is provided with at least one movable section and the movable section is oscillated as the pipe is moved through the J-tube riser, thereby reducing the force required to move the pipe.

Abstract: A method and apparatus is presented for connecting a flexible conduit bundle from a subsea wellhead to a floating platform. Movement of the floating platform relative to the subsea wellhead is compensated for by arranging the conduit bundle to be suspended in a catenary manner between the wellhead and the floating platform. The catenary form of the conduit bundle is maintained by bending the circuit around anchor blocks located a selective distance from the subsea wellhead.

Abstract: An apparatus and method for connecting a fluid conduit carried by an ROV to a fluid conduit of a subsea equipment assembly, such as a hydraulically-actuated device, in a non-binding manner. The apparatus includes a vacuum-locking device, such as a hydraulically-actuatable suction lock assembly, which is selectively actuatable to lock or unlock the apparatus with respect to the device of the assembly.

Abstract: An apparatus for securing a flowline to a structure near the seabed comprises a vertically oriented guide funnel placed atop a guide tube that is provided with a helical shoulder cooperating with an alignment key mounted on the flowline. During installation the flowline is stabbed into the guide funnel and guide tube thereby causing the alignment key to slide along the shoulder until a pair of hinge pins mounted on the flowline have entered into a pair of slots in the wall of the guide tube. Subsequently the flowline is hinged down to a horizontal position.

Abstract: The present invention provides a method and apparatus for connecting a flowline to a subsea structure. A riser and flowline connection tool are deployed downwardly to the subsea structure and a flowline terminal head, which is at the end of the flowline, is pulled to the flowline connection tool by means of a pullcable. Then the flowline terminal head is secured to the subsea structure and the flowline connection tool is recovered to the surface. The flowline terminal head consists of a connector hub with clamping surface to which the flowline is welded, and a flexible carrier pipe of interlocking metallic rings into which the end of the flowline is inserted. The carrier pipe limits the curvature of the flowline as the terminal head is bent into alignment with a flowline receptacle of the subsea structure. The flowline terminal head may include buoyant encircling rings which keep it free of difficult terrain in the vicinity of the subsea structure.

Abstract: The invention relates to a method and apparatus for remotely connecting or disconnecting upper flexible choke/kill lines (including auxiliary lines) to choke/kill lines of a floating drilling rig riser which has been lowered toward the sea floor. Remote stab assemblies are mounted to a stowable tension ring releasably secured to a housing secured to rig beams. In the stowed position, hydraulic stab connectors secured to travelling yoke assemblies are disconnected from each line. The travelling yoke assemblies are moved to an outer position so that the flexible drape hoses clear the space beneath the housing in order that a blowout preventer stack may be trolleyed in from the side of the rig moon pool during running or retrieval. The stack is lowered toward the sea floor by the riser. A telescopic joint is connected to the top of the riser and lowered through the housing and the tension ring.

Abstract: Disclosed in a method of and apparatus for lowering pipe strings and other objects, particularly pipe strings carrying anodes for cathotic protection, into and through the support structure of an offshore plateform. Skid beams are inserted into the support structure of the offshore platform below the top deck of the platform and above the water level, preferably at the plus twelve level of the structure. Mounted to the skid beams are winch and derrick means. The skid beams are inserted into the structure such that the winch and derrick means are positioned over the point at which the pipe string is to be lowered through the structure. The skid beams cantilever out from the structure such that they extend well beyond the outside perimeter of the top deck. The skid beams also serve as track for a trolley. Pipe string sections can be delivered to the trolley either from the top deck of the platform or directly from a barge.

Abstract: A subsea flowline connector for remotely connecting and releasing a first flowline such as a peripheral flowline on a marine riser to a complementary second flowline at a submerged location without the use of divers. Further, the seals in the connector may be remotely replaced without the need to bring the connector to the surface. Further, in one embodiment of present invention, a bundle of control/supply lines can be remotely connected to respective submerged lines at the same time as the flowline is connected.

Abstract: A method and apparatus for aligning a component with an underwater receptacle is disclosed. The component is attached to one end of a swing arm having a hook attached to the other end. The swing arm is lowered in the water until the hook engages a pivot attached to an underwater base at a selected distance from the receptacle. Following such contact, the component is lowered in an arcuate path defined by the rotation of the swing arm about the pivot until the component is aligned with the receptacle. In another embodiment of the invention, a stop is attached to a vertical guidepost at a selected distance from the receptacle and a guidepost engaging hook pivots to lower the component into alignment with the receptacle.

Abstract: A subsea control pod connector for joining conical interfaces (12, 18) having fluid openings (14, 20). A latch rod (54) carries a spherical ball (56) for vertical axial movement. A plurality of outwardly extending lock dogs (65) each has a spherical inner surface (66) sliding on the ball and an annular groove (72) around the outer surface. The groove surface transmits locking force to shoulder surfaces 68 and 70 located on the members to be joined.

Abstract: A subsea connector system for connecting the lower end of a structural core of a marine riser to a base which has been preset on the marine bottom. The box member of the connector system forms an integral part of a tapered section which, in turn, forms the lower end of the riser. The connector system, in a preferred embodiment, incudes a self-contained source of hydraulic fluid under pressure which actuates the connector to a locked position upon command. The connector also includes a back-up means for remotely locking the connector and three separate means for remotely unlocking the connector.

Abstract: Catenary hoses are installed individually between a floating production platform and a submerged riser buoy. During installation the hose end to be installed on the submerged riser buoy is linked with a remotely controlled handling tool which is lowered onto the buoy and which subsequently pulls an end of the hose into a hose receptor on the buoy. The hose is similarly connected to the platform by use of another remotely controlled handling tool.

Abstract: A system for aligning and securing the end of a subsea flowline to a subsea wellhead and guide base system associated with an oil or gas completion system which provides for the manipulation of the centerline of pins on the subsea flowline end connection attachment, the centerline of receptacles on the flowline receiving structure, and a centerline on pulling tool guidance means to a concurrent location such that the pins can engage the receptacles and thereby the flowline end can be positively locked into the flowline receiving structure at varying vertical rotational positions of the end of the flowline and subsequently when a desired vertical rotational position or elevation of the flowlines is achieved other pins will engage other receptacles and lock the flowline end attachment and therefore the flowlines against further vertical movement.

Abstract: The present invention provides a method and apparatus for connecting a flowline to a subsea structure. A riser and flowline connection tool are deployed downwardly to the subsea structure and a flowline terminal head, which is at the end of the flowline, is pulled to the flowline connection tool by means of a pullcable. Then the flowline terminal head is secured to the subsea structure and the flowline connection tool is recovered to the surface. The flowline terminal head consists of a connector hub with clamping surface to which the flowline is welded, and a flexible carrier pipe of interlocking metallic rings into which the end of the flowline is inserted. The carrier pipe limits the curvature of the flowline as the terminal head is bent into alignment with a flowline receptacle of the subsea structure. The flowline terminal head may include buoyant encircling rings which keep it free of difficult terrain in the vicinity of the subsea structure.

Abstract: The present invention provides a method and apparatus for connecting a flowline to a subsea structure. A riser and flowline connection tool are deployed downwardly to the subsea structure and a flowline terminal head, which is at the end of the flowline, is pulled to the flowline connection tool by means of a pullcable. Then the flowline terminal head is secured to the subsea structure and the flowline connection tool is recovered to the surface. The flowline terminal head consists of a connector hub to which the flowline is welded, a curved carrier pipe into which the end of the flowline is inserted, a bullnose to which the pullcable is attached, and a dovetail tenon which engages a dovetail receptacle to secure the terminal head to the subsea structure. The flowline terminal head may include buoyancy which keeps it free of difficult terrain in the vicinity of the subsea structure.

Abstract: A floating tube apparatus (7) for providing a sealed, reversible and remote-controlled connection between ducts, in particular underwater ducts or difficultly accessible ducts, provided with complementary connectors to connectors (8, 9) carried by the floating tube at its ends. The apparatus comprises a positioning device (17, 21, 22, 23, 24) for positioning the floating tube (7) relative to a reference plane defined by a rectilinear rolling path of fixed structure (18). The positioning device includes a ball joint (23, 24) mounted on the middle of the tube (7) and three carriages mounted on one another in such a manner as to enable each to be displaced rectilinearly along a displacement axis which is perpendicular to the displacement axes of the other two, the transfer carriage (17) which carries the other two carriages moving along the rolling path under the action of jacks (31A, 31B), and the carriage (22) carried by the other two carriages itself carrying the ball joint, and consequently the tube.

Abstract: A bottom anchor connector for securing the tension legs of a tension leg platform (10) having a flexible joint (26) between a first body member (22) and a second body member (24) including a latch carrier (44) having latch segments (46) thereon which react with an anchor receptacle recess (18) to provide the connection between the connector (10) and the anchor receptacle (R) when the bottom connector (10) is lowered into the anchor receptacle (R). The latch carrier forms part of a self-actuating installation and release mechanism and includes, in one embodiment, keys (46) which cooperate with the receptacle recess (18) to position the dogheads (50) of the latch segments (46) to be free of the receptacle recess (18) so that the dogheads may move within the inner wall of the receptacle without reacting to the recess (18) to release the bottom connector from the receptacle.

Abstract: In a marine anchor for coupling a tether to an anchoring chamber the tether terminates at a connector having a flange that abuts a flange of an anchoring chamber. A collet connector is expandible to trap flanges, in an external groove thereof, thereby establishing a primary load path. The mouth of the anchoring chamber is further provided with an out-turned flange engaged by locking fingers and operable by actuator means to establish a secondary load path from the anchoring chamber to the tether while the anchor is being established or released. The coupling can be separated without damage under high loads or when the tether is at an angle to the chamber.

Abstract: Apparatus for enabling a self-contained submersible module including a length of conduit for connection to a collector to be repetitively put into place and removed. The collector (3) is located on the sea bed, and said length of conduit (14) and said collector (3) have mating ends fitted with a releasable connector suitable for establishing said connection when the ends to be connected come into end-to-end engagement. The length of conduit (14) is mounted in the module (2) on a carriage (7) to enable said length of conduit to be moved out from said module to bring one of its ends (13) into contact with the end (5) of the collector. Once the length of conduit has made connection with the end of the collector, the carriage also enables said length of conduit to be moved in the opposite direction pulling said collector with it in order to connect the other end of the conduit to a well head (1).

Abstract: A hydraulic connection apparatus for use by divers or an underwater vehicle is disclosed which allows pressurized hydraulic fluid to be supplied to hydraulically-actuated devices carried upon subsea equipment. A pressurized fluid source carried by the underwater vehicle is placed in fluid communication with the hydraulically-actuated devices by the connection apparatus. The connection apparatus comprises a buoyant device that is allowed to float upwardly into a receptacle carried by a portion of the subsea equipment. Co-operating hydraulic connection elements carried by the buoyant device and the receptacle provide a pressure tight seal between the device and the receptacle. Pressurized hydraulic fluid then flows from the buoyant device and through the receptacle to the hydraulically-actuated devices carried upon the subsea equipment.

Abstract: A pipe-welding assembly is provided in which single-pass welding of one pipe length to another is accomplished by gas lasers mounted to rotate around the axis of the pipes to weld the pipe ends together in the gap between two axially aligned spaced pipe clamps. Weld-testing units are similarly rotated around the pipe axis. The pipe-welding assembly is mounted on a gyroscopically-stabilized platform, which can be located on a pipe-laying land vehicle, or on a pipe-laying ship for laying pipe lines on the ocean bed. If the ship is equipped with a pipe feed tower, with the pipe-welding assembly positioned at the base of the tower and a drawbridge provided for elevating successive pipe lengths angularly into the tower, pipe laying can be performed in the "J" configuration. If the tower is mounted so that it can be inclined angularly into a position approaching the horizontal, and the pipe-welding assembly can be similarly rotated on its stabilized platform, pipe-laying can be performed in the "S" configuration.

Abstract: The present invention provides a method and apparatus for connecting a flowline to a subsea structure. A flowline connection tool is deployed downwardly to the subsea structure and secured to the subsea structure. A flowline terminal head, which is at the end of a flowline, is then pulled toward the flowline connection tool by means of a pull-cable. The flowline terminal head is then secured to the subsea structure and the flowline connection tool is recovered to the surface.The flowline connection tool contains a prime mover means in order to minimize the length of cable exposed to forces encountered in pulling the flowline to the subsea structure.

Abstract: A device for permitting the relatively precise positioning of two geometrical axes respectively of two elements at least one of the elements being associated with means capable of assuring its displacement characterized in that it comprises in combination at least two acoustic emitters-receivers disposed in a first plane substantially perpendicular to one of said geometrical axes, said axis being defined as the first axis, and capable of emitting toward said axis, said two emitter-receivers not being located on a same line passing through said first axis and in that it comprises a third emitter-receiver situated outside of said plane.

Abstract: A method and apparatus are provided for connecting an offshore pipeline or flowline bundle to a deepwater subsea structure and then laying away from the structure. The pipeline or flowline bundle is deployed from a pipelay vessel while connected via a pullcable to a riser deployed from a drilling ship to make a connection with the subsea structure. The connection operation is facilitated by a remotely operated connection tool deployed at the end of the riser, which contains a winch for hauling in the pullcable, as well as other mechanisms for securing the pipeline or flowline bundle to the subsea structure.

Abstract: The plough has a front and a rear lifting assembly (60, 62) each including an arm (64, 80) which is extensible and angularly adjustable by hydraulic rams (65, 68; 81, 84). The arms carry rollers (74, 76, 78; 94, 96, 98) upon which the pipeline (110) is lifted by the arms. The plough can be positioned beneath the pipeline as the arms retract while supporting the pipeline as the plough approaches the pipeline from one side. Having been positioned, the plough advances to cut a trench, the pipeline being supported in yielding manner by the two arms, having their lifting rams (68, 84) connected to hydraulic accumulators. Pressurized gas in the accumulators maintains the rollers (74, 76; 94, 96) in contact with the pipeline as the plough moves up and down and pitches relatively to the pipeline, during ploughing. The plough requires no structure over the pipeline. The plough body (12) is not required to comprise parts which separate to allow positioning of the plough in relation to the pipeline.

Abstract: A pull in tool incorporating within its structure a winch 220 and a capstan 210. A track system 231 on the tool moves to engage openings 38 in the guidelineless reentry assembly 50. Thereafter the flow line termination 400 is passed down the track system 231 to achieve precise final positioning.

Abstract: A remotely controlled undersea vehicle has a manipulator arm articulated to a mast which is articulated on the vehicle. Jaws at the end of the arm are arranged to close around a collar of a conduit having an automatic connector end, and to connect control fluid passages of the jaws to passages in the collar which communicate the control fluid to the automatic connector end.

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: A device for connection of underwater cables or pipes to a submerged structure.

Abstract: A method and apparatus are provided for laying an offshore pipeline or flowline bundle to a deepwater subsea structure. The pipeline or flowline bundle is laid along a prescribed path, preferably U-shape, such that a pullhead at the terminus of the pipeline or flowline bundle falls just short of the subsea structure. A pull-in tool connected to the pipeline or flowline bundle by a short length of pull cable is then landed on and latched to the subsea structure, and the pipeline or flowline bundle is pulled up to the subsea structure by the pull-in tool and pull cable.

Abstract: Production from a subsea wellhead to a floating production facility may be realized with the use of a substantially neutrally buoyant flexible production riser which includes biasing means for shaping the riser in an oriented broad arc. The broad arc configuration permits the use of wireline well service tools through the riser system.

Abstract: Several embodiments are disclosed of a vertical type of flowline connector for providing a fluid connection between a horizontal flowline and an additional subsea facility. The upper and lower portions of the connector can be properly positioned relative to each other by simply lowering an upper female portion of the connector onto a lower male portion thereof. The lower portion of the connector at the subsea facility is provided with at least two vertically positioned, upwardly facing male mandrel connectors. The upper portion of the connector assembly includes at least two vertically positioned, downwardly facing corresponding female connectors designed to be lowered onto the corresponding male mandrel connectors. At least one of the female connectors is mounted on the connector assembly by a free floating mounting.

Abstract: A method and apparatus are provided for connecting an offshore pipeline or flowline bundle to a deepwater subsea structure and then laying away from said structure. The pipeline or flowline bundle is deployed vertically from a pipelay vessel to make a hinged connection with the subsea structure. The connection operation is facilitated by a flowline connection tool attached to the pipeline or flowline bundle and designed to be inserted into a funnel located either centrally or to one side of the subsea structure. The connection procedure consists of landing and securing the flowline connection tool onto the subsea structure, then hinging over and connecting the pipeline or flowline bundle to the subsea structure as the pipeline or flowline bundle is laid on the seafloor beginning at the subsea structure.

Abstract: An operation for re-entry to an underwater station equipped with a well apparatus.The device comprises, fixed at the end of a rod 1 of a train of rods, a support 2 from which is suspended a module 3 formed by uprights 8 disposed concentrically and connected together, a receptacle 13 being fixed to the center of the module, which is provided with a conical housing 30 for retaining connector 15 and a re-entry cone 14, said module being suspended from the support 2 by the guide line 19 whose tension is maintained constant by the pounding compensation means formed by two cables 7 fixed to the two ends of support 2 and to the two uprights 12 of the module, while passing over fixed pulleys 20 and 21 and a mobile pulley 22 weighted with a counterweight 23.A fitting device provided with means for compensating the pounding due to the swell.

Abstract: A method and apparatus are provided for positioning, aligning and interfacing a towed pipe segment to a previously installed pipe segment utilizing mating alignment sleds, one sled being attached to the trailing end of one incoming pipe segment and the other sled being attached to the leading end of the previously laid pipe segment, by connecting and drawing the alignment sleds together into a mating position and thereby aligning and connecting the two pipe segments.

Abstract: A method and apparatus for remotely replacing damaged guideposts attached to a subsea structure are provided. A receptacle is permanently attached to the subsea structure. The guidepost is inserted into the receptacle and is releasably connected thereto by one or more radially-oriented, spring loaded lock pins. Damaged guideposts are removed by applying an upward vertical force to the guidepost sufficient to shear the lock pin or lock pins. The upward vertical force is applied by a replacement tool capable of being remotely operated from the surface of the body of water. Following removal of the damaged guidepost, a new guidepost is inserted into the receptacle. Lock pins mounted in the new guidepost retract into the guidepost as it is being inserted. When fully inserted, the lock pins extend and engage a retaining groove formed in the receptacle thereby firmly locking the new guidepost in place.

Abstract: A method and apparatus for installing a pipeline riser (90) through a J-tube (40) at a spud can-founded, compliant, offshore platform (20) are disclosed. The J-tube is mounted on the platform above the maximum expected mudline (28). An upper longitudinal section (44) of the J-tube passes through guide rings (46) on the platform while a lower longitudinal section (48) is maintained free of the platform. After platform settlement, the J-tube is lowered to an elevation near the actual mudline (30). During riser installation through the J-tube, a lower end (54) of the J-tube is restrained from lateral movement by a latch (70) attached to the platform. Before production operations, the lower end is released from the latch so that flexibility of the J-tube accommodates movement of the platform.

Abstract: An offshore structure that is supported above the water's surface by at least one substantially vertically disposed leg which extends to the ocean floor. The structure is adapted to accommodate a vertical member or riser conductor having a deflector segment capable of engaging one or more fluid carrying conduits or risers which are lowered therethrough. The deflector segment is positioned to engage a lowering riser end so that the riser will be urged outwardly and away from the base of the structure. The riser or risers can thus be readily connected to subsea pipelines which terminate adjacent to the foot of the offshore structure.