Abstract: A pipeline connection assembly includes a landing platform and rotary or swivel connection hub which may be attached to a pipeline branch, termination, or manifold. The landing platform is mounted so that it may be rotated about the connection hub. This permits the installation of a subsea connection on a near level platform and allows the pipeline to be laid subsea with greater roll angles than would be acceptable otherwise. Orientation of the landing porch horizontally removes the requirement to manufacture the connection jumper to compensate for the roll differences in the hubs. In the preferred construction, the elevation of the platform can be adjusted by a remotely operated vehicle (ROV) and locked into place once the adjustment is completed.

Abstract: This invention relates to a method and equipment whereby a pig (11) launched into a gas injection line (5) can be inserted into a hydrocarbon flow line (2) in a position close to the subsea wellhead or manifold (1) without interrupting the flow of hydrocarbons and with minimum interference to the process of gas injection.

Abstract: A system for transporting a pig (28) along the interior of a pipeline (26), particularly for the purpose of installing a liner (12) in the pipeline by towing the liner behind the pig, in which a hydrostatic head is applied on either side of the pig and the head on the downstream side of the pig is reduced such that the pig is transported along the interior of the pipeline by the resultant pressure differential. Where the system is employed in a pre-existing subsea pipeline, the hydrostatic heads may be applied by means of risers (14, 24) and the pressure differential created by means of a pump (30) adapted to pump water out of the downstream riser (24). The liner may be pulled through a flooded pipe by means of a pig, cable, self-propelled pipe crawler, or by combinations of these. A further cable may also be employed to apply a back tension, and/or to limit the pulling force applied to the liner and/or to enable the liner to be pulled backwards.

Abstract: A riser system for connecting a seabed installation to a floating vessel consists of first and second fluid conveying conduits (13,14) connected by an articulated joint (7). In a standby condition the articulated joint (7) is anchored to the seabed, the two conduits (13,14) are not in fluid communication with one another and the upper conduit (13) rises substantially vertically with the aid of a buoyancy device (9). In use, the upper conduit (13) is pulled in to a floating vessel, thereby releasing the articulated joint (7) from the anchor (8) and allowing the joint to pivot in order to connect the upper and lower conduits (13,14) to allow passage of fluid therethrough.

Abstract: A device for transferring fluid between equipment on the seabed and a surface unit. At least one flexible pipe extends in a catenary curve. An intermediate buoyancy and support member associated with the pipe splits the pipe into two parts, an upper part and a lower part. The intermediate member imparts to a region of the upper part a concavity facing the seabed. A yoke on the pipe and a cable from the yoke retain at least one region of the lower part of the pipe. The cable is connected to a fixed member on the seabed for tensioning the lower part of the pipe. The cable and the fixed member impart a bend to the region of the lower part of the pipe, the concavity of which faces the equipment on the seabed. The intermediate member is connected to the fixed member. The cable between the lower part of the pipe and the fixed member has a length at least equal to the minimum bend radius of the lower part of the flexible pipe.

Abstract: This invention relates to a method and equipment to assist the flow of offshore oil production. At least three production flow lines are used, which are interconnected close to offshore well-heads or manifolds forming two U-shaped lengths of pipe acting as circuits for passage of the hydrocarbon mixture produced. A mechanical interface is periodically inserted into one flow line of the U-shaped branches of pipe and, driven by a volume of pressurized gas, travels along the one from among the two U-shaped pipe length to return to a gathering center. In its passage it pushes along the volume of hydrocarbon mixture which has accumulated in the flow lines.

Abstract: A riser arrangement increases the stability and/or decreases sensitivity to vortex induced vibration of risers of a riser system including steel tubular lines, SCRIBS and flexible hose risers leading to a floating storage/production vessel. A cross-link is placed between two or more steel tubular lines in order to enhance the stability of the riser system. Devices are coupled to the steel tubular lines for increasing their tension in order to increase the natural frequency of vibration in order to reduce sensitivity to vortex induced vibration.

Abstract: The present invention relates to a method and device for sealing the entrance of an elongated element (1) into the lower end of an offshore tube (8), --including the steps of arranging a plug-like device (2) on the element, --pulling a predetermined length of the element into the tube, --and fixing the plug on the element surface at the bellmouth entrance (7) of the tube, the outer diameter of the plug being somewhat smaller than the inner diameter of the tube. Expandable foam is injected to a space (11,12) between the outer surface of the plug (2) and the inner surface of the tube (8), --in order to substantially fill said space.The foam is supplied to the space (11,12) from at least one foam container (15) placed inside the plug, --via ducts (13,14) within the plug. The foam container (15) is operated from a drive gas cartridge (16) also arranged within the plug (2) and is operable by an ROV.

Abstract: The disclosure relates to a method of laying a seabed pipeline from a surface vessel. Pipe strings are assembled from their upper ends from the vessel for attachment in a pipeline extending from the vessel to the seabed. An upper end of a pipe string is attached to a trailing end of a pipeline, the pipeline is guided through a generally semi-circular curved path having an upwardly directed entry and a downwardly directed exit from where the pipeline extends to the seabed. The vessel is moved forwardly while guiding the pipeline around said curved path so that the pipe string passes around the path and is then released in a downwards direction towards the seabed until the trailing end of the pipe string is above sea level.

Abstract: The present invention provides for the connection of a pressure balanced stab and a manifold in which offsetting forces maintained on the stab allow it to remain in an inserted state within the manifold without the use of a significant amount of force to maintain the connection. The offsetting forces are contained within the stab through the use of C-ring seals on the stab, which are activated by a downward force created by an actuator. The compression of the C-rings is delayed until insertion is complete, therefore allowing an installation which does not damage the seals. The O-ring designs, used in prior pressure balanced stabs, are likely to be damaged upon insertion of the stab into the receptacle. The damage to the O-ring seals takes place when the O-ring, partially protruding from the stab, makes contact with the surface of the receptacle in such a manner that causes the O-ring seal to tear or become manipulated in a way that creates an ineffective seal.

Abstract: System and method for joining together two assemblies which can move one with respect to the other, especially in underwater installations, comprising a remote-operated vehicle (17) comprising propulsion means (21) and at least one equipment item (19, 20) including hauling means (20) which attach to the assembly considered as being fixed (2) during connection, means of attaching to the other assembly considered as being mobile and which has to be connected to the said fixed assembly, means (19) of winching the said hauling means, the said equipment item being at least partially housed in a skid (18), characterized in that the remote-operated vehicle (17) further comprises a front chassis (22) that pivots about a pivot axis, the said pivoting chassis comprising the said means of attachment to the mobile assembly, the pivoting of the said front chassis being controlled in such a way that as the mobile assembly is moved towards the fixed assembly, the said vehicle is kept constantly in an approximately horizonta

Abstract: A subsea pipe laying system is mounted on a ship and comprises a fabrication station where lengths of pipe are welded together to form a pipeline. The pipeline is then guided to a pipe laying zone where including a straightener under the control of a tensioner/clamping arrangement the pipeline is straightened and laid on the sea bed. The straightener and the tensioner/clamps are mounted on a ramp which can be tilted whereas the fabrication zone is on the deck of the vessel. The pipeline can either be fabricated in a forward direction and then have its direction and movement reversed to lay over the stern or be fabricated in an aft direction and laid over the stern.

Abstract: An apparatus for laying marine pipelines of the type in which the pipeline is assembled along a horizontal axis on board a pipelaying vessel prior to being launched therefrom; in which the pipeline is plastically bent to a desired launch angle and, in most cases, at least partially straightened thereafter. In preferred embodiments, the pipeline is bent through an angle greater than 90.degree.. In the most preferred embodiments, the pipeline is diverted through an angle of substantially 270.degree., plus or minus an angle allowing variation in the launch angle from the vertical, and crosses itself prior to entering the water. The pipeline (102) is diverted by being passed around a wheel-like diverter structure (104), the pipeline being assembled in multiple fabrication lines to produce stalks which are aligned and connected in a central firing line prior to being fed around the diverter structure. Other variations are also described.

Abstract: A seabed flowline is connected to a substantially conventional tanker serving as a floating storage facility by a system comprising a three-leg mooring and a flexible riser. The mooring comprises anchors connected by anchor risers to a common node, and a mooring pendant extending from the node to the tanker. The flexible riser comprises a flexible rubber hose extending from the seabed to the tanker. The hose has a top section secured along part of the mooring pendant, and an intermediate section provided with buoyancy and restrained by a tether to maintain it clear of the anchor risers.

Abstract: A device for connection or suspension between a detachable flexible or semi-flexible riser pipe (4) and a pipe system (14) on a fixed or floating platform or ship (15) has a rotary connection which is designed in such a way that the connection between the riser pipe (4) and the pipe system (14) is moment-free or mainly moment-free. The rotary connection may appropriately have a swivel housing (3) which, on one side, is fitted with a first tubular shaft (1) which is connected to the pipe system (14) on the platform or ship and, on the other side, is fitted with a second tubular shaft (2) which is arranged in a swivel housing at an angle of 90.degree. to the first tubular shaft (1) and which is connected to the riser pipe (4). The two shafts (1, 2) communicate with each other via a cavity in the swivel housing (3), but are closed to the surroundings at their ends.

Abstract: A remotely actuable launching system for inserting pigs into a pipeline includes a barrel that can accommodate a series of pigs end-to-end. The pigs are urged towards the forward end of the barrel where they are controlled by a pair of axially spaced actuators for release one at a time into the pipeline. Operation of the actuators is effected by a control system using high pressure nitrogen gas and which can be remotely operated to effect launching of a pig into the pipeline at any desired time, without the need for personnel to be on-site.

Abstract: A catenary riser support, for a floating offshore structure, that receives the riser and is attached to the floating offshore structure. The catenary riser support is formed from a tube that is rigidly attached to the floating structure and a flex joint in line with the catenary riser. The tube includes a gradual bend that complements the natural catenary curve of the catenary riser. A pipe adaptor attached in line with the flex joint and riser allow the flex joint to be pulled up against the tube. The flex joint allows the catenary riser to move relative to the floating structure.

Abstract: An end of a composite cylinder is formed about an end connection assembly having two longitudinally arranged pieces having a contour which prevents the withdrawal of the end connection assembly from the cylinder. The two pieces of the end connection assembly are relatively forced apart and a snap ring having a certain rest diameter is reduced in diameter and inserted into the end connection assembly to a position between the pieces. The snap ring then assumes its rest diameter positioned between the pieces, forcing them to maintain intimate contact with the inner surface of the cylinder, thus removing any residual gap from the assembly process and/or preloading the interface between the end of the composite cylinder and the end assembly prior to application of an axial load.

Abstract: The invention relates to a system for pull-in and interconnection of two pipelines in subsea position, whereof one first pipeline initially is freely suspended, while one second pipeline for instance is mounted on a bottom based manifold frame. The end section on the first pipeline is provided with a socket-like termination with a front end, which is provided with means (17) for coupling of the terminator (8) to complementary pipe coupling means (29) on the second pipeline (19). The terminator (8) is provided with a laterally directed, longitudinally shaped anchor element (10), and the manifold frame (22) is provided with receiving means (24) for receipt and fixation of the anchor element (10).

Abstract: An end of a composite cylinder is formed about a multipiece end assembly having a contour which prevents the withdrawal of the end assembly from the cylinder. The pieces of the end assembly are relatively forced apart and a spacer is positioned between the parts to maintain the pieces in intimate contact with the inner surface of the cylinder thus preloading the end prior to application of an axial load or removing any residual gap from the manufacturing process. The cylinder may have end assemblies at both ends and to which may be coupled external connectors such as flange members, for construction of a marine riser.

Abstract: The present invention relates to a system which makes use of a multiple reel on which groups of flexible lines supported by articulated structures (8, 9) are wound. The groups of flexible lines are interconnected at one end to flexible production and utility lines (4) emerging from the seabed and, at the other end, to connection blocks (10, 11) which may be connected to connection plates (15, 16, 17, 18) on at least one connection tower (13, 14) fixed to the vessel. As the connections are redundant, it is always possible to reposition one group of flexible lines while another group is connected, which gives the transfer system (2) total freedom of movement.

Abstract: Curvature limiter for a pipe running in a marine environment, more specifically a pipe riser (12) running between a sub-sea oil well (14) and a support (10) on the surface (16) of the sea. The curvature limiter (26) comprises at least two elements (28) which are substantially tubular and arranged around the pipe riser (12), these elements being joined together by an interconnection (30) which serves to limit the angular separation between the elements.

Abstract: A subsea connector system and method utilizing a skid (18) on the sea floor (F) four coupling a subsea conduit (16) carried by the skid (18) to a subsea conduit (12) on a relatively fixed subsea structure (10). A lift line device or structure (24) has an upper lift line (36) connected by a spreader bar (40) to a pair of lower guide lines (38) which are directed from a vertical position to a generally horizontal relation by J-tubes (30). The ends of the guide lines (38) have anchor members (42) thereon which are anchored to guides (46) on the subsea facility (10). Upon raising of the upper lift line (36), the skid (18) moves in a combined pulling and lifting motion to engage a side (52) of the subsea facility (10) for being guided into a docked position with aligned guides (46) on the subsea facility (10). In this position, an ROV (26) secures the skid (18) into a releasably locked position by insertion of retainer pins (not shown) into aligned openings (35, 51) of the skid (18) and subsea facility (10).

Abstract: A marine riser system for a bottom-supported platform which can be installed by divers without the use of J-tubes or I-tubes. A flowline, e.g. steel pipeline, is laid between a subsea well or the like, and a jacket of a bottom-supported platform. The free end of the flowline is curved upwardly in a catenary amd is attached to the jacket at a depth which is below the turbulence zone but is one which is substantially above the marine bottom; preferably at a depth at which divers can safely work. After the flowline is structurally attached to the jacket, the free end of the flowline is fluidly connected (e.g. by divers) to a substantially vertical riser section which is clamped within the jacket and which extends through the turbulence zone to the surface.

Abstract: A system for offshore production of hydrocarbons via a vessel arranged for quick connection to and disconnection from a submerged body. The system comprises an outer buoyancy member for introduction and releasable securing in a submerged downwardly open receiving space in the vessel, and a center member which is rotatably mounted in the outer member and is anchored to the sea bed and is connected to at least one riser extending between a production well and the vessel. A swivel device is arranged at the upper end of the buoy for interconnection and transfer of process fluid between the risers and a tube system on the vessel. The swivel device comprises an outer female member permanently fastened to the center member of the buoy with its opening coaxial with the center member, and an inner male member which may be lowered into and raised from the female member via an operator on the vessel.

Abstract: An apparatus and method for laying underwater pipeline which includes a plurality of buoyancy control valves formed thereon. Each buoyancy control valve includes an air escape hole formed in the pipeline with a sliding weight member disposed in a first position upstream immediately adjacent to an air escape hole. During use, the air escape holes enables air to escape from the pipeline as it sinks at one end and descends to the sea floor in a catenary. As it descends to the sea floor, the sliding weight member slides via gravity from a first to a second position on the pipeline. When disposed in the second position, the sliding weight member covers the adjacent air escape hole. A hydraulically controlled restraining chain is disposed around the pipeline to control the sliding action of the sliding weight member until the pipeline has reached a pre-determine depth.

Abstract: A marine riser system which effectively combines rigid (e.g. steel catenary risers) with flexible flowlines. Basically, the steel catenary risers, which are merely the end portion of submerged rigid flowlines, are curved upward through the water in a gentle catenary path to a large, submerged buoy, which, in turn, is moored to the bottom by tension leg tether lines at a depth below the turbulence zone of the water. Flexible flowlines are fluidly connected to the steel catenary risers at the buoy and extend upward through the turbulence zone to the surface.

Abstract: A continuous bend flexible/rigid riser system is provided for coupling a subsea location to an offshore platform or vessel. The riser system comprises a first rigid pipe section coupled at its upper end to the platform. A plurality of intermediate pipe sections are mutually coupled end to end, and are coupled in series with the first rigid pipe section by means of a plurality of flexible couplings. The lower end of the last in the series of intermediate pipe sections is coupled to the subsea location. The flexible/rigid riser system reduces bending stresses transmitted along the riser by allowing angular displacement of the pipe sections with respect to one another.

Abstract: A diverless flowline connection system for connecting a flowline to a subsea wellhead or other subsea structure. The diverless flowline connection system is used with a remotely operated vehicle. The diverless flowline connection system includes a frame assembly including clamping arms for mounting the frame assembly to the flowline. A pair of winches are mounted to the frame assembly. Each winch includes a winch line for attachment to the wellhead to which the flowline is to be connected. Each winch is independently controlled so that the lateral position of the flowline may be variously adjusted by controlling each of the winches. The diverless flowline connection system is of modular design to accommodate a wide variety of flowline diameters. The connection system can also be used to pull from the wellhead. Winch line guillotines are provided for severing the winch lines and the clamping arms release the flowline in the event of hydraulic system failure.

Abstract: An ocean riser assembly for conveying fluids between the seabed and the surface of the sea includes a fluid conveying pipe formed into a helical configuration or into a planar cyclically undulating configuration, such as a sinusoid, that extends longitudinally from the bottom of the sea to the surface. One or more flexible and preferably elastic tension members extend in the longitudinal direction of the riser assembly and are secured to the pipe at spaced intervals, so that they absorb tension forces applied between the ends of the riser assembly. The helical or undulating configuration of the riser pipe decouples axial stresses in the pipe caused by internal fluid pressure from stresses caused by external tension forces acting on the riser assembly, the external tension forces being converted to torque and bending moments acting on the pipe itself. This arrangement permits substitution of carbon steel pipe for flexible pipe, at substantial cost savings.

Abstract: Vortex-induced vibrations of unsupported segments of subsea pipelines are reduced by providing a shroud that can be lowered onto the subsea pipeline wherein the shroud creates turbulence that interferes with vortex shedding and thereby reduces the amplitude of vibrations are reduced. The preferred shroud comprises a plurality of rods supported in vertical planes along the sides of the pipeline. Installation can be performed without the use of divers.

Abstract: An apparatus for making up threaded pipeline joints includes conventional casing tongs supported on a truck for movement between a stowed position and an operative position over the side of the truck with the axis of rotation of the casing tongs being generally horizontal. A roller on the front of the truck is raised or lowered by an extensible motor controlled by the tong operator to align the pin end of the joint to be made up with the collar of the made up pipeline. The operator manipulates the support to position the casing tongs over a pipeline joint to be made up and rotates the tong dies to rotate the pipeline joint.

Abstract: To compensate considerable movements between a floating unit and a seabed structure which are interconnected by a fluid line, the invention proposes to embody this fluid line in an upper catenary and a lower portion. The upper catenary is on the one hand supported by the floating structure and on the other hand by a subsurface buoy. The lower portion is on the one hand supported by the subsurface buoy and on the other hand connected to the seabed structure. This lower portion is provided with buoyancy beads. In this way it is possible that the floating structure may be displaced a considerable distance relative to the seabed structure. In addition, the system can withstand considerable environmental loading. This means that the connection between the seabed structure and floating unit can be maintained even under unfavorable conditions.

Abstract: A tool for the remote-controlled pulling, aligning and connecting of a subsea conduit to a subsea installation. The tool includes a framework, a pulling wire with a pulling head which can be releasably attached to the end of the subsea conduit and also optionally aligning means which bring the ends of the conduit which are to be connected in line with one another. The tool has a frame pivotally mounted on the framework around a substantially horizontal axis oriented substantially at right angle to the axis of the conduit and at almost the same height at which the conduit will finally lie, said frame including a grip elevator which can grip and hold the pulled conduit and manipulate the end of the conduit between a slanting pulling position and a final substantially horizontal connecting position.

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.

Abstract: A flowline connector will remotely connect subsea flowlines without the assistance of a diver. The flowline connector has a frame which supports a seal carrier plate assembly. Springs allow axial movement of the carrier plate assembly during engagement of mating hubs of flowlines. A metal seal carried by the carrier plate assembly engages conical seats in the hubs of the two flowlines. An elastomeric test seal located radially outward of the metal seal seals between flat faces of the hubs of the flowlines. The test seals elongate radially to wipe the sealing surfaces clean during the makeup.

Abstract: A pipe attachment and receiving apparatus for severing and handling a subsea pipe. The apparatus including a chassis adapted to mount onto a subsea pipe and clamps for clamping the chassis to the subsea pipe. An interface assembly is connected to the chassis. The interface assembly is adapted to extend and retract relative to the chassis. The interface assembly is adapted to receive modules. The modules are adapted to be releasably mounted to the interface assembly. A cutting module is mounted to the interface assembly to cut the pipeline and a docking module is mounted to the interface assembly to repair the pipeline with a replacement spool.

Abstract: An offshore pipeline system is provided, comprising a pipe section which is curved so as to bend upon a variation of the distance between the ends thereof. The pipe section is provided with a pair of first connectors extending in downward direction, each first connector being located at one of said ends of the pipe section. The system further comprises a pair of second connectors extending in upward direction and located at a distance relative to each other so as to allow connection of each first connector to one of said second connectors, means for lowering the pipe section through the water towards the second connectors and guide means for guiding each first connector towards one of said second connectors when the pipe section is lowered through the water so as to connect the first connectors to the second connectors.

Abstract: A pipeline connector apparatus comprising piston actuated means for gripping and sealing a pipe comprising a cylinder having an inner surface, the cylinder having a first groove for receiving a spring biased ring, a piston movable in the cylinder and actuating one of the gripping and sealing means, the piston having a second groove holding a spring biased ring. A plurality of compressible and relaxable spring biased rings are provided, each having an outer surface and a radius such that each will compress within the second groove and will expand within the first groove. The outer surfaces of the different rings have shoulders of different widths which allows the operator to control the piston stroke in the cylinder. The apparatus further comprises a means for predetermining and/or monitoring the displacement of the pistons.

Abstract: Apparatus (1) for connecting first (9) and second (33) parts of an under-water connector comprises a first carrier (2) adapted to receive the first connector part (9) and having an axial guide socket (10), and a second carrier (3) adapted to receive the second connector part (33) and having a plug (4) arranged to engage axially in the guide socket (10) for connection of the first (9) and second (33) connector parts. The plug (4) has a nose portion (14) which tapers forwardly to a front end (15) having a lateral dimension less than that of the guide socket (10), and a waisted portion (16) rearwardly of the nose portion (14) with a lateral dimension less than that of the guide socket (10).

Abstract: A device for mounting a flexible line including a curvature limiter. The device for mounting a flexible line on a structure, including a hollow rigid member forming part of the structure or fixed to the structure, and which the flexible line passes through after having been pulled with the aid of a pull cable fixed to one end of the flexible line, in particular on the end fitting mounted on the latter for connecting it to the structure, and a curvature limiter engaged on the flexible line and secured to fixing means able to interact with fixing means secured to the hollow rigid member for fastening the curvature limiter to the structure.

Abstract: A method, using a crane-equipped depot ship, for automatically repairing an underwater pipeline even if installed at great depth, comprising substantially the following steps: cutting off the damaged pipe piece by a single working module which, lowered onto the sea bed by a crane and clamped about said pipeline, removably supports the cutting apparatus; removing the concrete from the facing ends of the cut pipeline by said single working module which removably supports the removal apparatus, this being provided with an expansion-centering head; installing connectors by a sonar head alignment apparatus removably supported by said working module; and installing the replacement pipe piece by said working module using a reference and guide apparatus clamped about said ends of the pipeline. Specific apparatus for implementing the method are also described.

Abstract: A pipeline connector and repair system for sealingly connecting the ends of first and second pipes together without welding or bolting. First and second connectors are provided at each end of a pipe joint and are inserted between the ends of the first and second pipes to be connected, the connectors are extended outwardly for enclosing the ends of the first and second pipes, and dual slip means and dual seal means in each of the connectors are hydraulically set for making the repair.

Abstract: A device for laying flexible tubular conduits from a floating support is provided. The flexible tubular conduit has insulating sheaths and reinforcements where the conduit includes a recoverable flexible tubular handling conduit connected to the flexible tubular conduit. The flexible tubular handling conduit has sufficient mechanical strength to withstand the combined action of the highest internal pressure and the axial tensile force corresponding to the apparent weight in water of the length of tubular handling conduit which is suspended between the floating support and the floor, and on the other hand, the isolated action of the axial tensile force corresponding to the apparent weight in water of the length of flexible tubular conduit when the latter is suspended between the floating support and the floor by the flexible tubular handling conduit.

Abstract: There is disclosed an apparatus for use in drilling an offshore well wherein the upper end of a riser is intermittently supported from a floating vessel to permit the lower ends of additional pipe sections to be connected thereto and then lowered through the table for connection at its lower end to an underwater wellhead. The riser is supported from the vessel in such a manner as to absorb the load of the riser as an additional section is landed on its upper end, and then carry the load of the riser as the vessel tilts or rolls without imposing undue bending loads on the riser.

Abstract: An apparatus for making up threaded pipeline joints includes conventional casing tongs supported on a truck for movement between a stowed position and an operative position over the side of the truck with the axis of rotation of the casing tongs being generally horizontal. An operator manipulates the support to position the casing tongs over a pipeline joint to be made up and rotates the tong dies to rotate the pipeline joint. A torque gauge is incorporated into a backup wrench to provide a visual signal that the joint is made up. A dolly towed behind the truck supports the made up pipeline a short distance behind the truck and transfers the made up pipeline in a predetermined path as the truck drives down the pipeline right-of-way as the threaded joints are made up. A dope applier is cantilevered from the dolly and applies dope to the pipeline when the truck moves along the right-of-way.

Abstract: The present invention provides a method of cleaning a pipeline using a gel pig of a graft copolymer of a hydroxyalkyl cellulose prepared by a redox reaction with vinyl phosphonic acid. The gel pig is formed by hydrating the graft copolymer in an aqueous liquid. The gel pig is crosslinked by the addition of a Lewis base or Bronsted-Lowry base, to the gel in an amount sufficient to initiate crosslinking of the graft copolymer. Contaminants entrained in the crosslinked gel pig during the cleaning process may be separated by the addition of a pH reducing agent to the pig whereby the viscosity of the gel is caused to decrease. The gel may be used for further cleaning after contaminant separation by addition of an additional quantity of the Lewis base or Bronsted-Lowry base.

Abstract: A subsea production system effects line connections between a manifold and adjacent satellite wells. The radial distance between each well (37) and a central manifold (38) is reduced to an operational minimum. The manifold is provided with connection terminals (45) including at a lower portion, a hydraulic type connector (47), and at an upper portion a reentry mandrel (50). A supporting structure (53) of the connection terminal (45) consists at the lower portion of a mud mat (54) centrally of a waiting mandrel (55). A lateral structure (56) is provided at an upper portion with eyelets (57), and the upper portion mounts a reentry funnel (58). Various methods are effected for completing line connections between such a manifold (38) and adjacent satellite wells (37).

Abstract: This invention concerns a mechanism for the interchanging of guide-posts worked by remotely controlled vehicle which consists of guide-cones (6) provided in the side of base beam (2) that supports socket (4) of guide-post, which guide-cones are placed axially and enter all around the socket (4) of guide-post, to create an operating channel inside the socket (4) while guide-post (8) is provided with a channel all around its bottom (1) to house a locking-pin (12). Guide-post (8) is placed inside its respective socket (4) so that the operating channel created by the guide cones (6) inside socket (4) matches channel all round the bottom (10) of socket, exactly, so that locking of guide-post (8) takes place by means of turning the locking-pin (12) housed in channel all around (10) the guide-post (8) by means of a remotely operated vehicle or suitable tool.

Abstract: A diverless and guidelineless method to connect two subsea flowlines by a jumper assembly is provided. Pivotable stabs and fluid connection means are provided on each end of the jumper assembly. The stabs mate into receptacles located on the subsea flowline connections. The flowline is preferably lowered vertically and hinged over while sequentially landing the two pivotable stabs into their respective stab receptacles.