Abstract: A pipeline laying ship and an improved method of laying a pipeline in a marine environment is disclosed. The pipeline laying ship is a dynamically positioned barge or self-propelled dynamically positioned vessel with a hull having a deck area that supports a pair of reels. The reels are independently rotatable, and are position to generally port and starboard relative to one another. A pipe joint storage area is provided for containing multiple joints of pipe. One or more pipeline welding stations are provided on the deck next to the reels, the pipeline welding stations being positioned to join the joints of pipe together to form an elongated pipeline that can be wound upon a selected reel of said pair of reels. A tower is provided for guiding the elongated pipeline as it is unwound from a selected reel, the tower including at least a bend controller, a straightener and a tensioner.

Abstract: A bottom-to-surface connection installation for an undersea pipe. The installation comprises a vertical riser having its bottom end connected to an undersea pipe on the sea bed, and having a float at its top end, and a pipe connecting a floating support at the top end of the vertical riser. The connection between the riser bottom end and the undersea pipe is via an anchor system having a base on the sea bed. The base holds and guides junction elements between the bottom end of the riser and the end of the lower end of the undersea pipe. The junction elements comprise a rigid pipe element presenting an angled bend and a pipe coupling element which are fixed to a moving support of the base. The junction elements are fixed to the moving support and are free to move only in translation in a single longitudinal direction.

Abstract: A subsea tool (10) designed to pull pipeline ends (PE1, PE2) towards each other is disclosed. The tool (10) comprises a first and a second main body (1, 2) that are able to be displaced to and from each other and have limited freedom of motion relative to each other. The first main body (1) comprises a frame construction (5) having means (11b) for guiding onto and fixed attachment to one of the pipeline ends (PE1). The second main body (2) comprises a frame structure (6) having means (18) for guiding onto and retaining the other pipeline end (PE2). A number of guiding means (15, 16) are provided on the first main body (1) for co-operation with complementary guiding elements (20, 21) provided on the second main body (2). A pulling device (3) is arranged between the first and second main body (1, 2) and is designed for pulling the main bodies (1, 2) including the respective pipeline ends (PE1, PE2) towards each other.

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

Abstract: A vessel (1) comprises a rotatable turret (14) and a supporting structure (3) over or on the turret for supporting a swivel (5). The swivel comprising an inner and an outer ring (21, 21?; 22, 22?) which can rotate with respect to each other and which define at least one fluid distribution path from a geostationary fluid riser (19) connected to one ring (22, 22?) to a product outflow pipe (18) connected to the other ring (21, 21?). A rig (2) is mounted over the turret area above or below the swivel (5), and a substantially rigid pipe extends from the rig, through a moonpool of the turret towards the sea bed, the rigid pipe being in line with the swivel.

Abstract: The flying lead deployment apparatus with one reel assembly is made of a frame assembly; a reel assembly with flying lead disposed in the frame assembly adapted to rotate to distribute the flying lead; a first ROV-flying lead interface connected to the frame assembly and one end of the flying lead; a second ROV-flying lead interface connected to the reel assembly and the other end of the flying end; a drive assembly connected to the reel assembly with a counting gear adapted to count the number of times the reel assembly rotates, an adjustable rack gear, and a locking mechanism connected to the adjustable rack gear and the reel assembly adapted to stop the reel assembly when the counting gear reaches a predetermined number; and a friction brake connected to the frame assembly and reel assembly adapted to apply friction to maintain constant tension on the flying lead.

Abstract: A method of welding together the ends of outer pipe sections (16A, 16B) of pipe-in-pipe pipeline to be laid on a seabed employs an annular member (5) interposed between adjacent lengths of pipe. The annular member comprises a first axial part (11) which fits within the end of the first outer pipe section, and a flange part (12) which is interposed between the adjacent ends of the two lengths of outer pipe sections (16A, 16B) to be joined. The flange part (12) of the annular member (5) projects radially outwardly beyond the inside of the outer pipe sections (16A, 16B) and terminates radially inwardly of the outside of the outer pipe sections (16A, 16B), and provides some of the welding material for the joint.

Abstract: The present invention relates to an installation providing a bottom-to-surface connection for an undersea pipe resting on the sea bottom, in particular at great depth, the installation being of the hybrid tower type having a static base placed on the sea bottom. In the installation of the present invention, said pipe resting on the sea bottom is connected by a flexible pipe element constituting a bend to a vertical riser whose bottom end is held in fixed position relative to said base.

Abstract: A marine plough includes twin, complementary steering mechanisms, one or more soil-engaging fins, which are able to be steered, and a tow rope attachment mechanism that enables adjustment of the position of the tow rope retention point relative to the plough. This alters the position at which the line of a tow rope crosses the longitudinal axis of the plough, so that the plough can operate at offset tow positions. The tow rope attachment mechanism includes a bridle having two bridle limbs terminating at respective bridle limb retention points. The adjustment of the position of the tow rope retention point relative to the plough is done by moving the bridle rope retention points or adjusting the relative length of the bridle limbs. The bridle limb retention points can be moved, using cylinders, from towing positions to lifting positions at which the tow bridle can be used to lift plough in a substantially level attitude.

Abstract: An offshore hydrocarbon production system includes a vessel (12) with a turret (16), and a fluid swivel (50) on the turret that is connected to risers (41-43) that extend to the sea floor (26), wherein a drilling/workover rig (60) on the vessel can lower tubing (65) toward the sea floor without danger that the tubing will wrap about the risers when the hull weathervanes. The rig is mounted on the turret. Pipes (54) that extend from the rotatable part of the fluid swivel to fittings (55) on the hull (14), are supported on a gantry (80) that is fixed to the hull and having a gantry middle portion (106) that extends over the turret. The gantry middle portion extends higher than the top (88) of the rig.

Abstract: A rotatable pipeline end termination. A conduit is attached to an end of the pipeline. One or more collars are attached to the conduit. A ring is rotatably received on the collar. A pipeline support structure such as a flat bottom closed skid having the function of a mud mat is attached to the ring. The ring may be free floating for rotation or may be manually activated to rotate the termination to the correct orientation so as to be flat on the sea floor for full bearing contact.

Abstract: Apparatus and method for electrically heating a segment of a subsea pipeline are provided. The annulus between the pipes electrically isolates the pipes, but at the ends of the segment the concentric pipes are electrically connected. The inner pipe may be thermally insulated. Electrically insulating water stops are provided to act as flood control barriers in the event the outer pipe is breached. Collars on seals around the water stops may help avoid electrical shorts and packets of super-absorbent may be in place to further reduce the risk of electrical faults.

Abstract: The invention concerns a seafloor-surface connecting installation for a submarine pipeline (10) set on the seafloor, in particular at great depth, of the hybrid-tower type comprising a static base (13-18) set on the seabed. In the inventive installation: 1) said vertical riser includes a terminal pipe portion (51), and a flexible joint (19) which allows angular movements (&agr;) of the upper part (52) relative to said terminal pipe portion (51); and 2) the terminal part (11) of said pipe resting on the seabed has a an elbow-type terminal curvature; 3) said terminal portion (51) of the vertical riser is connected to said terminal curvature (11) by a single connecting element; and 4) said base plate (13-18) rigidly maintains in fixed vertical position and linked to each other via said connecting element (12): said terminal pipe portion (51) and said elbow-type terminal curvature (12) the latter facing upwards.

Abstract: A loading arrangement includes a riser that extends from a subsea structure to a coupling element for coupling the riser to a vessel. The coupling element includes a buoy body which is connected to a retention member via a flexible connection part. The retention member, such as a submerged buoy, is attached to anchor lines which at or near their end parts are provided with buoy. The connection part, which can be a cable or a frame structure has a relatively high tensile strength to anchor the vessel to the sea bed and to prevent drift of the vessel when tension is exerted on the connection part and the anchor line.

Abstract: The disclosed catenary anchor leg mooring system includes a cylindrical hull portion which reduces the tendency of the cylindrical hull to roll and pitch in response to the action of winds and waves. This motion reduction comes from changing the diameter and draft of the cylindrical hull.

Abstract: An apparatus and a method for deployment of an object in a fluid, e.g. the sea, with at least a first (4) and a second cable (5), to be connected to the object, the apparatus comprising winch elements for reeling in and out the cables (4, 5) in order to allow movement of the object with respect to the apparatus. The apparatus is provided with a bundling apparatus (10) for bundling the cables, when reeled out, in order to provide a single cable assembly between the apparatus and the object during deployment. The apparatus and the method are not only adapted for bundling cables when reeling out the cables during deployment, but the apparatus and the method are adapted for removing a bundling element (13) from the cables when reeled in during recovery.

Abstract: An apparatus and a method for connecting underwater conduits by remotely operated devices including a vehicle capable of underwater excursions, and an apparatus and a method for connecting conduits.

Abstract: A pipeline laying ship has a hull with a deck area and a moon pool that extends through the hull midships. The pipeline welding stations are provided on the deck in between the bow of the hull and the moon pool. A superstructure is positioned in front of the moon pool and extends upwardly from the deck. The superstructure includes a track that is comprised of a plurality of supports for supporting a pipeline to be launched to the seabed. The superstructure has upper and lower sections that are removable with respect to each other. The upper section pivots upon the lower section in the preferred embodiment. The superstructure lower section supports the welded pipeline as it is being fabricated in a first plane that includes a central longitudinal axis for the pipeline. The upper section supports the pipeline on a second plane that forms an acute angle with the first plane.

Abstract: Apparatus is described for transferring cryogenic fluid from a first vessel (5) to a second vessel in an offshore environment. The apparatus comprises a partly submerged floating dock (1) with variable buoyancy means (14, 15) operable to alter the draught of the dock (1), enabling it to be lowered in the water and raised again to engage the dock (1) with the second vessel. A single point mooring system (3) is attached to the dock (1) via flexible connections means (11,19).

Abstract: A mechanical joint assembly for a steel catenary riser (SCR) is disclosed. The lower section of the mechanical joint assembly is comprised of steel or alternate high strength components, rather than elastomers to absorb the high loads and increase life of the unit. The lower mechanical joint assembly provides for reduction of bending moments and resulting fatigue stresses at the SCR top by removing resistance to movement in all angular directions, providing increased lateral and in-plane angles to provide increased construction tolerances for the pipeline approach corridor. Pipeline approach angle increase is accommodated by providing dual orthogonal trunnions in addition to an axial swivel. The upper mechanical joint assembly, acting without riser tension loads, allows for the use of either flexible high-pressure pipe or swivel arrangements to accommodate angular flexure before the rigid deck piping.

Abstract: Methods are provided for installing an electrically heated pipe-in-pipe pipeline on the seafloor. Inner and outer pipe segments are formed and the inner pipe is coated and insulated. Coating may include sprayed polyurethane foam and insulating half-shells that are placed around welds. Epoxy is preferably coated on the inner pipe before other coatings. The segments are loaded on a lay barge and water stops are preferably installed in the annulus as the pipeline is formed. Water stops may be formed by placing a liquid polymer in the annulus and allowing it to cure.

Abstract: A pipeline laying ship and an improved method of laying a pipeline in a marine environment is disclosed. The pipeline laying ship is a dynamically positioned barge or self-propelled dynamically positioned vessel with a hull having a deck area that supports a pair of reels. The reels are independently rotatable, and are position to generally port and starboard relative to one another. A pipe joint storage area is provided for containing multiple joints of pipe. One or more pipeline welding stations are provided on the deck next to the reels, the pipeline welding stations being positioned to join the joints of pipe together to form an elongated pipeline that can be wound upon a selected reel of said pair of reels. A tower is provided for guiding the elongated pipeline as it is unwound from a selected reel, the tower including at least a bend controller, a straightener and a tensioner.

Abstract: A method for assembling and delivering a drivepipe to a drill site. The method has the following steps: The drivepipe is assembled at a shoreline assembly station. Floatation devices are attached to the drivepipe and the drivepipe is floated in the ocean. The drivepipe is towed with tow vessels to a drill site. The drivepipe is delivered in a horizontal orientation to a drilling vessel at the drill site. An upper end of the drivepipe is attached to the drilling vessel and the tow vessels are detached from the drivepipe. The drivepipe is pivoted about its point of attachment to the drilling vessel until the drivepipe is vertically oriented. The buoyancy function of the floatation devices attached to the drivepipe is deactivated. The floatation devices are removed from the drivepipe. The drivepipe is equipped with a driving mechanism and the drivepipe is lowered with a running string from the drilling vessel to the sea bed.

Abstract: A power supply system for electrically heated pipelines is provided. A variable frequency drive supplies power to the pipeline from an external source of electrical power. An isolation transformer and a contactor or isolating switch may be used between the variable frequency drive and the pipeline. A controller may be used in the system to control special sequences of power level and other needs for heating a pipeline.

Abstract: An apparatus for transferring hydrocarbons from a subsea source to a vessel, wherein the risers are suspended from a rotating body and communicate with a swivel unit including a number of swivel rings having outlets connected to a pipe system on the vessel. The apparatus includes a block arranged between the risers and the swivel unit and provided with interior ducts for connection of the risers with respective swivel rings, and a device for selective closing of the ducts are arranged between the risers and the swivel unit. The device is integrated in the block. In an advantageous embodiment, the block is also provided with a device for selective interconnection of two or more of the ducts in the block.

Abstract: A conduit structure (44) connects subsea oil wells to a floating structure (12) such as a vessel, in shallow water, the conduit structure providing a low cost and reliable fluid connection during drift of the vessel. The conduit structure includes a seafloor riser support (50) with a lower end (52) fixed to the seafloor and an upper end (54) lying a plurality of meters above the seafloor. A flexible pipe or hose (46) extends in a double catenary curve from the top of the seafloor riser support, at a downward incline away from the seafloor riser support and then at an upward incline to the floating structure. A rigid pipe (70) can extend along a plurality of meters of the height of the riser support to minimize the required length of flexible hose and facilitate installation.

Abstract: An offshore loading or production system for dynamically positioned ships, comprising a riser means (4) extending between a supply means and a coupling head (5) for connection to a connecting means (6) on the ship (1). The riser means (4) comprises a lower riser portion (7) extending along the seabed (8) and being arranged to take up a wavy shape above the seabed by means of at least one bottom-anchored first buoyancy element (9), and an upper riser portion (10) of which the lower end is connected to the lower riser portion (7) via a second buoyancy element (11), and of which the upper end is connected to the coupling head (5) via a swivel unit (12). The second buoyancy element (11) is connected to a supporting anchoring (17) extending along the seabed (8) in a direction away from the lower riser portion (7).

Abstract: The present invention relates to a ball swivel connection/joint intended to be used at anchoring of in particular deep sea water boring rigs and other off-shore platforms but also other heavy units at sea, whereby it comprises a partly spherical wire connection receiving a wire receiving unit a substantially annular link connector as well as a holding element for a fixed or movable fixation of the link connector as well to an annular space arranged in the partly spherical connector, whereby the link connector and the wire receiving unit are rotatably arranged relative each other.

Abstract: A method and apparatus for near vertical laying of a pipeline offshore by a pipe laying vessel includes a tower to which is attached a strongback that load pipe sections from a supply point on the vessel into the tower where the lower end of the pipe section is welded onto the upper end of a pipe line that extends into the sea while the strongback returns to the supply point for a second pipe joint. Where the pipe section includes a bulky item such as a valve assembly box, after the pipe section has been welded to the pipeline the pipe section is moved generally horizontally out of the tower and a hoisting cable lowers the pipe section to a predetermined depth below the tower. The hoisting cable then returns the pipe section and attached pipeline to their original position.

Abstract: An underwater cable branching apparatus has an elongate cable junction housing for positioning in line between two cables for installation underwater. The housing has through bores at each end for receiving the ends of respective first and second cables, and the cables are each terminated at a respective connector in the housing for releasably connecting the two cable ends together. Each connector is pivotally and retractably mounted in the housing by a respective pivotal linkage, such that the connectors can be separated and rotated upwardly out of the housing by an ROV for selective connection to other cables in an underwater network, to permit branching.

Abstract: A method and apparatus for connecting underwater conduits and more specifically, to a method and apparatus which is capable of performing the diverless connection of underwater flowlines and connection of these flowlines to underwater structures such as flowline bases, xmas trees, and templates. The connection of underwater conduits is facilitated by the use of a remotely operated vehicle and connection apparatus both being launchable and recoverable by a support vessel. The connection apparatus adapted to mount on at least one of the underwater conduits and the connection apparatus allowing for docking of the remotely controlled vehicle which then captures and draws a second conduit to form a continuous flowline. Then a connection apparatus is clamped upon the conduits. The apparatus then bolts the conduits together.

Abstract: A flowline connector having a first connector portion for mounting on a first piece of subsea equipment, such as a wellhead. A second connector portion of the flowline connector is attached to an end portion of a flowline. Each connector portion has a respective guide interengageable by lowering the second connector portion, on the end portion of the flowline, into the first connector portion. The guides allow the second connector portion to pivot relative to the first connector portion to bring the first connector portion and the second connector portion into axial alignment for make-up of a fluid tight connection therebetween. The second connector portion has a subsea equipment package, for example chokes, gas/water separators, gas liquifiers, pumps and the like, for connection to the first piece of the subsea equipment.

Abstract: A method and a device for the protective encapsulation of an oil or natural gas pipe loop within an outer jacket or cover for installation on the seabed, where the end portions of the pipe loop are coupled to an underwater structure. The protecting encapsulation of the pipe loop within the cover or outer jacket is performed on the surface and the pipe loop is lowered, substantially completely protected, to an installation position. On the seabed, the outer jacket or cover in which the pipe loop is confined may be covered with a layer of chippings.

Abstract: A line up and connection installation comprises an elongated pipe receiving structure, a line up device for lining up double-walled pipes or pipe components and a connection station for connecting the lined up pipes or pipe components. The line up device has at least two gripper means. The gripper means are each movable in translation in a plane which lies substantially perpendicular to the axial direction of the pipe receiving structure. At least one of the gripper means is movable in the axial direction of the pipe receiving structure. The line up device positions a first pipe or component in such a manner with respect to a second pipe or component that they can be connected to one another at their ends in a connection station.

Abstract: A method for laying electrical cables from a first offshore wind power plant to a second offshore wind power plant. The method comprises placing the cable to be laid in the tower or the foundation of the first offshore wind power plant before the plant is erected, erection of the first offshore wind power plant, taking a tow line from one wind power plant to the other wind power plant, and drawing the leading end of the cable from the first wind power plant to the second wind power plant while releasing the cable from the tower or the foundation component of the first wind power plant.

Abstract: An apparatus for releasably securing a tubular structure of a floating installation to an anchor fixedly secured to an underwater floor has a first connection element mounted at one end of the tubular structure and a second connection element configured at one end to couple with the first connection element. The second connection element includes a pair of guides secured thereto which extend horizontally therefrom. A hinge device connects the second connection element to the anchor such that the second connection element is pivotably connected to the anchor. A plurality of cables connect to both the tubular structure and the anchor, whereby the pair of guides cooperate with the cables such that when the cables are under tension, the cables urge the second connection element to pivot and align with the first connection element.

Abstract: Apparatus is disclosed for transferring fluid between a point (5) on the seabed, such as a wellhead, and a floating vessel (1). The apparatus comprises a flexible pipeline (4), the upper end of which is attachable to the vessel (1). A second flexible pipeline (8) is attached at one end to the wellhead (5). A structure (6) is mounted on the seabed and includes a member (7) which is movable relative to the structure (6). The lower end of the first pipeline (4) and the upper end of the second pipeline (8) are mounted on an end of the movable member (7) which is remote from the seabed structure (6). When the first flexible pipeline is stretched out in response to the vessel (1) moving about under the action of wind and current, the movable member (7) is displaced relative to the seabed structure (6) in order to allow the pipeline (4) a greater range of movement before it becomes stretched beyond its safe limit.

Abstract: A marine pipelay vessel equipped with a pipe laying apparatus comprising a pipe handler for moving the pipe into its raised launching position, a pipe connection station for connecting together pipe ends when in the launching position, a pipe support for maintaining the pipe in a raised position, a static clamp for releasably securing the upper end of a previously launched pipe, a pipe launcher for controllably launching the raised pipe stalk in which the pipe launcher comprises a second mobile clamp adapted to be releasably secured to the pipe such that the second clamp may be raised and lowered controllably over a predetermined stroke distance between the uppermost and the lowermost stroke position relative to the vessel.

Abstract: A heated flowline electrical isolation joint is disclosed for introducing current into a pipe-in-pipe system having an outer and an inner pipe. A hub presents a load flange having tension and compression load shoulders on its terminal end and connects to the inner pipe on its other end. An end flange presents an end flange load shoulder on one end and a high strength, highly electrically insulative first ring separates the compression load shoulder from the end flange load shoulder which engage therethrough in a load bearing relationship. A plurality of o-ring seals secure the compression load shoulder-to-first ring-to-end flange load shoulder interfaces. A retainer flange connects to the end flange on one end and to the outer piper on the other end, encircling the hub and presenting a retainer flange load shoulder.

Abstract: System and method for coupling of a bottom based pipeline to an adjacent riser pipe or another pipeline, of the kind wherein is utilized a bottom based coupling frame. The underside of the frame (2) is designed in order to undergo displaceable movements along the sea bottom or on a fundament thereon both during and subsequent to coupling of the pipelines to the frame. On the frame are mounted coupling members for one importing and one exporting pipeline, and a pipe connection between the pipe couplings, optionally including a valve and other equipment. In accordance with the method, a tool including a winch and a pulling wire, is mounted on the frame whereby the frame, including the pipeline, can be pulled together in order to accomplish the coupling operations.

Abstract: A subsea steep wave lock and guide mechanism (1) for elongated articles (2) such as cables, pipes and umbilicals provides a substantially horizontal inlet (6) for the article at seabed level and a substantially vertical flexible article outlet (4) leading to the steep wave. The lock and guide mechanism (1) includes a number of lockable/releasable gates (20-24) for restricting and defining allowable movements of the article in the horizontal as well as in the vertical direction.

Abstract: Underwater conduits are connected by remotely operated devices including a vehicle capable of underwater excursions, and apparatus for connecting conduits, by a method controlled from a support vessel on the surface comprising the steps of launching a remotely operated vehicle from the support vessel; launching connection apparatus from the support vessel; manipulating the remotely operated vehicle to dock with the connecting apparatus; installing the connection apparatus at one of the conduits; activating a docking clamp means using the remotely operated vehicle to capture the end of the other conduit; activating the connection apparatus to draw the second conduit to the first; connecting the two conduits together to form a continuous flowline; providing a sealed connection and recovering the remotely operated vehicle and connection apparatus to the support vessel.

Abstract: A method for enhancing the flow of heavy crude oil by heating a subsea pipeline is disclosed in which a pipe-in-pipe subsea pipeline is established having a flowline for transporting well fluids in the form of an electrically conductive inner pipe concentrically surrounded by an electrically conductive protective outer pipe and the inner pipe is electrically insulated from the outer pipe along the length of the subsea pipeline. The pipe-in-pipe subsea pipeline is electrically heated continuously along its length to maintain the temperature of crude oil at a level facilitating pipeline transportation, this heating comprising passing alternating electrical current along the exterior surface of the inner pipe and along the interior surface of the outer pipe. In this manner the crude oil can be maintained at a temperature at which viscosity does not prevent efficient and economical pipeline transport.

Abstract: A method and apparatus for connecting underwater conduits and more specifically, to a method and apparatus which is capable of performing the diverless connection of underwater flowlines and connection of these flowlines to underwater structures such as flowline bases, xmas trees and templates. The connection of underwater conduits facilitated by the use of a remotely operated vehicle and connection apparatus both being launchable and recoverable by a support vessel. The connection apparatus adapted to mount on at least one of the underwater conduits and the connection apparatus allowing for docking of the remotely controlled vehicle which then captures and draws a second conduit to form a continuous flowline.

Abstract: A ship type floating oil production system for access to subsea wells through installation of surface wellheads on a ship type surface vessel on the sea comprises a cylindrical turret moored to a seabed is located within a moon pool formed in the ship type surface vessel such that the ship type surface vessel is freely rotatable about the cylindrical turret. A plurality of riser pipes have a rigid structure and extend downward to subsea wells through the cylindrical turret, and each riser pipe is provided at its top portion with a surface wellhead including valves of the riser pipe. Accordingly, workover operations can be facilitated as needed by running workover tools through the surface wellhead of the corresponding riser pipe through use of a work-over-rig installed on the ship type surface vessel.

Abstract: A mooring system for a Floating Production, Storage and Offloading vessel (FPSO) employs a vessel mounted rotatable turret and a single point mooring arrangement. The mooring arrangement includes a single anchor chain that is removably attached at a top end to the vessel, and is attached at a submerged bottom end to three sealed anchored leg chains. The anchor chain is secured to the vessel by means of a chain stopper that is centrally located in the rotatable turret, and allows the vessel to rotate freely about the anchor chain's vertical axis. One or more submerged fluid carrying risers are detachably connected to a swivel stack positioned above the mooring table in line with the rotational axis of the anchor chain so that the risers and the anchor chain will not become entangled with one another during vessel rotation.

Abstract: The anchoring mechanism comprises a guide post lock formed in the shape of a sleeve. The sleeve is movable inside a guide post and can lock the guide post to a funnel of a seabed frame by means of lower lockpins passing through radial bores in the guide post. The guide post lock can be raised by an anchor lock for a wire. Raising the anchor lock enables the lockpins to be moved radially inwards. The anchor lock is also able to raise the guide post by upper lockpins in axial slots in the guide post lock passing through upper, radial bores in the guide post. The lower lockpins are pressed inwardly by means of the lower beveled edge of the funnel.

Abstract: A method for installing an offshore pipeline is disclosed in which the inner and outer pipes are structurally connected at a terminal end of a pipe-in-pipe flowline and centralizers are placed in the annulus to provide lateral support and maintain concentricity between the two pipes and to prevent buckling of the inner pipe. The working end of the pipeline is suspended under construction in a substantially vertical position within slips at the weld floor of a J-lay installation barge and sections of inner and outer pipe are added. Inner pipe is added by sections by grasping and orienting the section of inner pipe to a vertical position and the section is brought into abutting position with the inner pipe at the working end of the pipeline under construction, welded in place, and the weld is coated with an arc resistant material.

Abstract: A dynamic control cable string or umbilical intended to hang in catenary form between a connection point on the seabed and a connection point located at the sea surface which can be attached to a floating structure; the umbilical is of the type that is low in weight per running meter and comprises flowlines and optionally current-conducting cables, all of which are twisted around the longitudinal axis of the string and are spaced apart from an axially extending core member and lie in channels in spacers for free axial movement of the cables and conduits in the channels; the core member, throughout the entire length of the control cable string functions as a load-bearing member and, in a portion of the length, all fluid transport and signal communication takes place peripherally relative to the core member.

Abstract: A system for direct electric heating of a subsea pipeline is disclosed in the form of a pipe-in-pipe flowline having an electrically conductive outer carrier pipe and an electrically conductive inner pipe or flowline arranged longitudinally, substantially concentrically within the outer pipe. An annulus is defined between the inner and outer pipes and a pipe insulating joint assembly structurally joins, but electrically insulates, the inner and outer pipes at a first end of the subsea pipeline. A power input provided on the surface facilities is electrically connected across the inner and outer pipes at the first end of the pipeline, and an electrical pathway completes the circuit by connecting the inner and outer pipes at the second end of the pipeline.