Abstract: A compensating suspension element that includes a flexible cable, a flexible pipe and a catenary riser pipe and a connecting device connecting the flexible cable, the flexible pipe and the riser without buoyancy.

Abstract: A composite marine riser may be formed, in one embodiment, of a pair of threaded metallic sections having threaded external surfaces. The threaded external surfaces may taper from a larger to a smaller diameter. The composite material may be formed over the threaded external surfaces, which surfaces serve to transfer force from the metallic sections to the composite material.

Abstract: The present invention relates to a method and to a system for limiting vortex-induced vibrations on a riser suspended at one end from a support and subjected to substantially transverse fluid flows. The system comprises suspension means (10) for hanging the riser from the support, which include displacement means for moving the end in a transverse direction in relation to the principal axis of the riser.

Abstract: A running string for a subsea completion comprises an upper section (70) which may be a coiled tubing (CT) injector unit as shown, or a wireline lubricator (FIG. 8). A lower section (60) provides wireline/CT access to production/annulus bores of a tubing hanger (not shown) attached to tubing hanger running tool (62). A flow package (64) in the lower section (60), together with BOP pipe rams (86) and annular seal (88), directs production and annulus fluid flows/pressures to the BOP choke/kill lines (78/76). The upper and lower sections allow installation and pressure/circulation testing of, and wireline/CT access to, a subsea completion, without the use of a high pressure riser.

Abstract: The invention relates to flexible risers for transfer of hydrocarbons between a sea bed installation and a vessel (10) floating at the sea surface. The riser (18) is provided with means (20) for protecting the riser (18) from impacts. The protection means (20) covers at least the upper part of the riser (18) and is retractable to an inactive position. When in operation, the riser protection means (20) is either suspended from the vessel (10) or from a submerged turret buoy, forming part of a mooring system for the vessel (10).

Abstract: This invention relates to a marine riser tower (112, 114) for use in the production of hydrocarbons from offshore wells. The riser tower (112, 114) includes a plurality of fluid conduits, which may comprise production flow lines (P), gas-lift lines (G), water injection lines (W) and/or umbilicals (U). The conduits are supported in a single structure, and at least one of said conduits is provided with its own insulation within said structure.

Abstract: A new marine oil production riser system for use in deepwater applications is disclosed. An efficient means for accommodating movements of the host facility, while maintaining riser top tension within the limits for long-term riser performance. Long riser stroke lengths can be accommodated without requiring complex interfacing with the topsides. The riser assembly comprises: a generally extendable substantially non-vertical section having an upper end adapted to be in flow communication with a generally vertical marine riser carried by a facility floating on the surface of a body of water, and having a lower end adapted to be in flow communication with a fluid source on the seafloor; and tensioning means, mechanically connecting the upper end of the marine riser with the lower end of the marine riser, for biasing said ends towards each other.

Abstract: The invention relates to a marine riser tower having a plurality of rigid metallic conduits bundled together with a metallic tubular core. The conduits may include production lines for hydrocarbons, water injection lines, and/or gas lift lines. A production line or gas lift line is located within the core, while the water injection line is located outside the core.

Abstract: A buoyancy system to buoy a riser of an offshore oil platform includes buoyancy compartments coupled around an elongated internal beam. The internal beam can withstand loads between the oil platform and the buoyancy system, while the buoyancy compartments provide buoyancy. The internal beam includes an elongated stem, a plurality of webs extending radially outwardly from the stem, and a plurality of transverse flanges attached to the outer edges of the webs.

Abstract: A floating offshore platform, of the type having a buoyancy can disposed within a support structure, includes a can guide assembly that has at least two compliant compression pads that are configured and arranged to provide a non-linear load-versus-deflection characteristic in response to impact loads generated by the impact of the can against the guide assembly. At least one of the compression pads is substantially stiffer (less compliant) than the other pad. The pads are arranged so that the relatively soft pad absorbs the impact load before the relatively stiff pad is engaged. In one embodiment, first, second, and third compression pads are arranged vertically, the upper and lower pads being softer (more compliant) than the middle pad. In another embodiment, a first, relatively soft, compression pad coaxially surrounds a second, relatively stiff compression pad.

Abstract: The present invention relates to an instrumentation assembly intended for an offshore riser (2) operated from a floater (1). It comprises a central processing unit (PC) connected by conducting cables (27) to: a plurality of modules (21–25) fastened to various points of the riser length, the modules comprising measuring means allowing dynamic location of said points in space, another locating module (26) fastened to the lower end (LMRP) of said riser, a series of detectors (W, C, M/W) for measuring the environment: wind, wave, current, an assembly for measuring the position (DGPS, P) of the floater. The measurements are synchronized with one another, managed and recorded by means of the central processing unit.

Abstract: A method of preparing and operating a subsea well (23), comprising the steps of: locating a drill-through subsea tree (24) on a subsea wellhead; sealingly connecting a high pressure drilling riser (22) between the tree and a drilling platform at the sea surface; mounting a blow out preventer (16) at the top of the riser (22); drilling the well through the drilling riser and the subsea tree; and establishing a production connection between the tree (24) and a production collection facility at the sea surface through a production riser (52) which is separate from the drilling riser (22).

Abstract: Apparatus for suppressing vortex induced vibrations on a marine element of a riser system wherein the riser system comprises at least one umbilical element. Systems comprising and methods of using said apparatus to suppress vortex induced vibrations. The apparatus, systems, and methods comprise module elements which provide: i) a surface around a marine element for installing VIV suppression devices; and ii) passages for housing the at least one umbilical element.

Abstract: Method intended for automatic control of an underwater pipe for connecting the lower end of the pipe to a wellhead, wherein the following stages are carried out: Stage 1: determining a mathematical model expressing the position of the lower end of the pipe as a function of the position of the upper end of the pipe, Stage 2: determining a reference path leading to the wellhead, Stage 3: from the mathematical model determined in stage 1, determining control laws allowing to control the path of the lower end of the pipe, Stage 4: applying determined motions to the upper end of the pipe so that the position of the lower end is as close as possible to the reference path determined in stage 2.

Abstract: A buoyancy can for supporting an offshore oil and gas riser includes an axial bore through which the riser extends coaxially, and a radio-axial slot extending through a side of the can and into the axial bore. A pair of spaced-apart support features are disposed coaxially on the riser, and the can includes a pair of corresponding sockets in the axial bore thereof. The sockets are adapted to receive and vertically support respective ones of the support features in a complementary, axial engagement. The can is placed in the water and moved laterally relative to a fully assembled, vertically supported riser such that the riser passes through the radio-axial slot of the can and into the axial bore thereof without the need for disassembly of the upper portion of the riser. The relative vertical positions of the can and riser are then adjusted such that the support features engage and seat within respective ones of their complementary sockets.

Abstract: Methods and apparatus for installing electrically heated composite umbilicals within subsea flowlines containing produced hydrocarbons as immersion heaters to prevent waxes and hydrates from forming within the subsea flowlines that could block the flowlines. The electrically heated composite umbilicals may be installed, or retrofitted, into existing subsea flowlines. Such retrofitted electrically heated composite umbilicals provide an alternative for previously installed, but failed, permanent heating systems. A hydraulic pump installed on the distant end of an electrically heated composite umbilical also provides artificial lift for the produced hydrocarbons. Other electrically heated umbilicals used as immersion heaters are described. Such immersion heater systems may be removed from the well, repaired, and retrofitted into flowlines without removing the flowlines. Near neutrally buoyant electrically heated umbilicals are described which may be installed great distances into flowlines.

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 method for controlling drag and vortex induced vibration in a substantially cylindrical element by providing an ultra-smooth surface about the cylindrical element. The system for controlling drag and vortex induced vibration utilizes a substantially cylindrical marine element having an ultra-smooth effective surface.

Abstract: The disclosure concerns a method and apparatus for repairing or structurally reinforcing an oil and gas well tubular member, or an assembly of tubular members. The assembly to be repaired can include a smaller diameter inner flow conveying conduit (or production tubing) and a larger diameter concentrically placed surface casing, providing an annulus in between the production tubing and the surface casing. A third casing pipe of largest diameter, the drive pipe is placed around the surface casing string. Other “conductor” casing pipes can be positioned around the surface casing inside the drive pipe. Part of the surface casing string (or other conductor pipe) can suffer damage due to corrosion. A sleeve or repair member is placed around the casing string or other tubular member at a damaged portion.

Abstract: The method relates to a riser comprising a main tube and auxiliary lines. Each tubular element forming the auxiliary lines is fastened at one end by a complete link with the central tube and at the other end by a link allowing a longitudinal play J with the central tube. The method provides adjustment of play J so that, on the one hand, during conventional drilling operations, the elements forming the auxiliary lines slide in relation to the central tube and, on the other hand, during show control or testing operations, the elements forming the auxiliary lines form hyperstatic assemblies with the central tube. The method thus allows to prevent buckling of the peripheral lines when they are under pressure because they work under hyperstatic conditions.

Abstract: A frame and system for adding buoyancy to a riser used in connection with floating platforms is provided which, in some example embodiments, includes a stem attached to multiple supports which include flanges arranged to take impact and abrasion loads off an internal buoyancy module. An air management system is also provided.

Abstract: Pipe for great water depths allowing transfer of a fluid between a floating support and a point situated below and at a distance from the water surface, characterized in that it comprises: at least one flexible part connected at one of its ends to the point situated below the surface, at least one rigid part connected to the flexible part at one of its ends and to the floating support at the second end, the rigid part being held up onto the floating support by holding means allowing this part to be essentially tensioned under the effect of its own weight.

Abstract: A frame and system for adding buoyancy to a riser used in connection with floating platforms is provided which, in some example embodiments, includes a stem attached to multiple supports which include flanges arranged to take impact and abrasion loads off an internal buoyancy module. An air management system is also provided.

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 riser recoil control system (10) adjusts tension forces (F1, F2) applied to a marine riser (60), which is attached to an anchored, floating vessel (30) and a wellhead (80). The riser (60) is attached to the vessel (30) using tension forces (F1, F2) asserted by riser tensioners (20). Each tensioner (20) has an air shutoff valve (110), and an orifice-controlled fluid valve (120). A disconnection sensing means (200) provides a disconnect signal when the riser (60) is disconnected from the wellhead (80), which closes the valves (110, 120) and adjusts the tension forces (F1, F2) applied by the tensioners (20). The invention includes a method for adjusting the tension forces (F1, F2) applied to the riser (60), including sensing the disconnect signal and adjusting the tension forces (F1, F2) supplied to the riser (60) by closing the air shutoff valves (110) and partially closing the orifice-controlled fluid valves (120).

Abstract: The disclosure describes a spoolable compliant guide, a system including a spoolable compliant guide and injector and methods for using the compliant guide, where the guide is designed to connect at one end to the injector and at its other end to a remote installation having a seal and to allow coiled tubing to be inserted into the installation through the seal. Because the guide permits a substantial distance to exist between the injector and the installation seal and functions as a crimp or band resistor for the coiled tubing, the guide enables the injector to be conveniently positioned remote from the installation such as a wellhead and assumes a compliant shape between the injector and the installation allowing dynamic relative movement between them without the use of heave compensators. Thus, for subsea installations, the injector, its control system and coiled tubing reels can all be located on the water's surface for ease of access and maintenance.

Abstract: The invention is directed to pressure lines for use with equipment associated with drilling and production risers, and in particular, pressure lines having breechblock connections with the equipment and with choke and kill lines for use in connection with different sized blowout preventer stacks (“BOP stacks”). The pressure line systems and choke and kill line systems of the invention include a breechblock connection for quick and easy removal and installation of the pressure lines to riser equipment and the choke and kill lines to BOP stacks. Additionally, the choke and kill lines of the invention may include a coupling system having a BOP connector, or plate assembly, for permitting one set of choke and kill lines to be used on various sized BOP stacks. The plate assembly is in fluid communication with a first choke or kill line connector.

Abstract: An offshore oil well riser system comprises one or more tubular conduits suspended from a floating platform and having bottom ends extending downward substantially vertically toward the sea floor. A bottom end connection and tensioning assembly is disposed at the bottom ends of the conduits and comprises a jumper for connecting the bottom end of each conduit to an associated sub-sea oil well, a weight for applying a vertical tension in the conduits, and an apparatus for constraining the bottom end of the conduits against horizontal movement, while enabling them to move freely in a vertical direction and to pivot freely at their bottom ends in response to motions of the platform on the water surface. The riser system is useful with a wide variety of floating platforms, and can be employed in either dry tree or wet tree completion systems.

Abstract: A riser for connection between a vessel and a fixed connection point on the seabed, in the form of an “L”, where the bottom riser arm is connected to the fixed point (2) on the seabed and the top riser arm (3) is connected to the vessel at the point (4). An elastic element (5) is connected to the bend (6) between the riser's arms and an anchoring point (7) on the seabed.

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 flowline is described for producing hydrocarbons from a subsea well that is comprised of a substantially neutrally buoyant tubular composite umbilical. The flowline may possess electrical heating apparatus within the tubular walls of the tubular composite umbilical to prevent waxes and hydrates from forming within the flowline and blocking the flowline. The electrical heating apparatus is comprised of at least one electrical conductor disposed within the tubular walls of the composite umbilical that conducts electrical current that is used to heat the tubular composite umbilical. The tubular composite umbilical that contains any produced hydrocarbons is substantially neutrally buoyant in the sea water adjacent to the subsea well. Positively neutrally buoyant tubular composite umbilical flowlines are also described.

Abstract: A system for establishing fluid communication between a floating body and a wellhead on the seafloor includes a rigid, self-tensioning riser for fluidly connecting the floating body and the wellhead. The riser defines a major axis extending from the floating body to the wellhead. The riser is formed with a series of pre-formed curves that absorb and release energy in response to the heave and surge of the floating-body by flexing in a direction essentially parallel to the major axis. The series of curves may be in a single plane (e.g., sinusoidal), or in multiple planes (e.g., helical).

Abstract: A riser support system for use in a body of water comprises a buoyant and ballastable support structure and a plurality of substantially vertical and rigid risers each of which is attached to the inside of the support structure at a location below the center of buoyancy of the support structure and below the surface of the body of water. Usually, each riser passes through the inside of a single tube in the support structure. Typically, the riser support system is used to support a plurality of risers and their surface wellheads inside the hull of an offshore platform, usually in such a manner that the axial movement of the risers and support structure is independent of the axially movement of the hull. By attaching the risers at a location below the center of buoyancy of the riser support structure, riser load adds to instead of decreases inherent stability and therefore the structural payload efficiency of the overall floating platform is improved.

Abstract: An arrangement and a method to control and regulate the bottom hole pressure in a well during subsea drilling at deep waters: The method involves adjustment of a liquid/gas interface level in a drilling riser up or down. The arrangement comprises a high pressure drilling riser and a surface BOP at the upper end of the drilling riser. The surface BOP havs a gas bleeding outlet. The riser also comprises a BOP, with a by-pass line. The drilling riser hasan outlet at a depth below the water surface, and the outlet is connected to a pumping system with a flow return conduit running back to a drilling vessel/platform.

Abstract: A cylindrical buoyancy unit is composed of separate sections which are held together to surround a marine object such as a riser or pipe with additional conduits. The sections combine to define an internal cavity which is shaped to conform with the marine object. Each unit section is a thermosetting resin composite with a bulk interior of syntactic foam and an outer layer of different characteristics and an intermediate reinforcement layer. The intermediate layer is disposed close to the outer layer and is mechanically embedded but not tightly bonded into the structure. The intermediate layer is made as a mesh of high strength polymer fibers.

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 buoyancy system to buoy a riser of an offshore oil platform includes buoyancy compartments coupled around an elongated internal beam. The internal beam can withstand loads between the oil platform and the buoyancy system, while the buoyancy compartments provide buoyancy. The internal beam includes an elongated stem, a plurality of webs extending radially outwardly from the stem, and a plurality of transverse flanges attached to the outer edges of the webs.

Abstract: A subsea riser disconnect assembly 10 may be actuated from a drilling rig DR by axial movement of an upper riser 35 relative to a lower riser 28, for disconnecting the upper riser 35 from the lower riser 28. A subsea riser valve assembly 20 may be actuated from the drilling rig DR by axial movement of the upper riser 35 relative to the lower riser 28, for sealing an interior portion of the lower riser 28 and well bore WB below the subsea riser valve assembly 20. A drill pipe disconnect 30 may be actuated from a drilling rig DR, either onshore or offshore, for disconnecting an upper portion of drill pipe 236 from a lower portion of drill pipe 240. The drill pipe disconnect 30 may be actuatable by hydraulic and/or mechanical forces applied to the drill pipe disconnect 30 from the drilling rig DR. The drill pipe disconnect 30 may be compatible for use with or without the subsea riser disconnect assembly 10 and/or the subsea riser valve assembly 20.

Abstract: An offshore oil well riser system that compensates for the motions of an associated floating platform comprises a vertical pipe section supported by the floating vessel and extending downward from the vessel substantially perpendicular to the sea floor, and a horizontal pipe section connected to the associated sub-sea well equipment and extending away from the equipment substantially parallel to the sea floor. A angled elbow pipe connects the horizontal pipe to the vertical pipe. At least one of the horizontal and the vertical pipes incorporates a flexing portion comprising a plurality of recurvate sections of pipe connected end-to-end with alternating curvatures. In one embodiment, the central axis of the flexing portion lies in a single plane and takes a sinusoid path. In another embodiment, the central axis of the flexing portion takes a three dimensional helical path.

Abstract: The invention relates to a bed to surface connection for an underwater pipeline (11), resting on the seabed, in particular at great depth, of the hybrid tower type, comprising a static base (151-152) resting on the bed. According to the invention said pipeline (11), resting on the seabed is connected by means of a flexible pipeline element (12) with an elbow bend, to a vertical riser (5), the bottom end of which is fixed with relation to said base.

Abstract: A flow assurance system includes an inner pipe disposed within an outer pipe to assure flow through the outer pipe. During installation and relative axial movement with the outer pipe, the inner pipe is nearly neutrally buoyant or fully neutrally buoyant in the fluids of the outer pipe and may extend partially or completely through the outer pipe. The inner pipe may be anchored at one end within the outer pipe. The inner pipe is preferably composite coiled tubing that is installed using a propulsion system. The system may allow fluids to flow through the inner pipe and commingle with the fluids in the outer pipe or may flow fluids through the inner pipe to the exterior of the outer pipe. Hot fluids may pass through the inner pipe to maintain the temperature of the fluids flowing through the outer pipe and chemicals may flow through the inner pipe to condition the fluids in the outer pipe. Tools may be attached to the end of the inner pipe for conducting flow assurance operations within the outer pipe.

Abstract: A device in the riser-tensioning device or a vessel (1), in which a wire (30) is connected to a riser (8) and extends from the riser (8) up to and over pulley wheels (18′, 18″) and on to a wire-tensioning device (22), the two parts of the wire (30) extending in opposite, essentially horizontal directions out from the pulley wheels (18′, 18″).

Abstract: Methods and apparatus for installing electrically heated composite umbilicals within subsea flowlines containing produced hydrocarbons as immersion heaters to prevent waxes and hydrates from forming within the subsea flowlines that could block the flowlines. The electrically heated composite umbilicals may be installed, or retrofitted, into existing subsea flowlines. Such retrofitted electrically heated composite umbilicals provide an alternative for previously installed, but failed, permanent heating systems. A hydraulic pump installed on the distant end of an electrically heated composite umbilical also provides artificial lift for the produced hydrocarbons. Other electrically heated umbilicals used as immersion heaters are described. Such immersion heater systems may be removed from the well, repaired, and retrofitted into flowlines without removing the flowlines. Near neutrally buoyant electrically heated umbilicals are described which may be installed great distances into flowlines.

Abstract: A method for processing oil from oil wells having water bound locations whereby it is necessary to place the process containment vessels upon host structures that are floating and subjected to a swaying motion caused by the wave action of the water in which the host structures float. The process containment vessels are of a vertical cylindrical configuration to minimize their footprint and to mitigate the effect of tilting on the spatial process geometry inside of the vessels and further the vessels contain internal baffles that create horizontal flow patterns inside of the vertical vessel for a more efficient gravity separation process.

Abstract: This invention provides a production riser system that enables fluid communication in a deepwater drilling environment through the use of a variable buoyancy device supporting both a hybrid riser tower and an steel catenary riser (SCR) system. Fluid communication is enabled between a surface production facility or unloading buoy and local and remote subsea (or remote non-subsea) production and export systems.

Abstract: Keel joint assemblies are described that permit a degree of rotational movement of a riser within the keel of a floating vessel and greatly reduce the amount of stress and strain that is placed upon the riser, as well. Keel joint assemblies described provide a limiting joint between the riser and the keel opening that permits some angular rotation of the riser with respect to the floating vessel. Additionally, the limiting joint permits the riser to move upwardly and downwardly within the keel opening, but centralizes the riser with respect to the keel opening so that the riser cannot move horizontally with respect to the keel opening. In described embodiments, the limiting joint is provided by a single annular joint that allows that riser to move angularly with respect to the can. In some embodiments, the keel joint assembly incorporates a cylindrical stiffening can that radially surrounds a portion of the riser and is disposed within the keel opening.

Abstract: The invention is directed to a tensioner/slip-joint module for providing a conduit from a floating vessel at the surface of the ocean to the blowout preventer stack, or production tree, which is connected to the wellhead at the sea floor. The tensioner/slip-joint module compensates for vessel motion induced by wave action and heave and maintains a variable tension to the riser string alleviating the potential for compression and thus buckling or failure of the riser string. The tensioner/slip-joint module of the present invention preferably includes at least one mandrel having at least one hang-off donut; at least one upper flexjoint swivel assembly, at least one radially ported manifold, at least one tensioning cylinder, and at least one slip-joint assembly combined in a single unit.

Abstract: The present invention provides a metal lined composite riser section for use in offshore applications featuring a traplock metal-to-composite interface to secure a plurality of structural composite overwrap layers about a metal liner assembly. Each traplock is formed with at least one annular groove or channel which has been made in the exterior surface of the metal liner assembly. The annular trap grooves may be of various geometries and may be arranged adjacent to each other to form a traplock having 2 to 8 or any number of grooves required to ensure proper adhesion between the composite overwrap layers and the metal liner assembly. A number of structural composite overwrap layers are secured about the assembly by building up alternating combinations of helical and hoop fiber windings to form a composite material. The present invention also provides a method of making composite riser sections using either a mandrel or counterweights to facilitate the composite fiber winding process.

Abstract: The present invention discloses a method of re-manufacturing a composite riser section having a damaged original metal liner. An expandable replacement liner is inserted into the bore of the composite riser section and is positioned to cover the liner. An annular recess may be formed circumferentially into the damaged portion of the metal liner to accommodate the replacement liner. The replacement liner is radially expanded within the composite riser section and a seal is created to prevent fluid inside the composite riser from flowing around the replacement liner, through the damaged liner and to the outside of the composite riser.

Abstract: The invention relates to a marine riser tower (112, 114) having a plurality of rigid metallic conduits bundled together with a metallic tubular core. The conduits may include production lines for hydrocarbons (P), water injection lines (W), and/or gas lift lines (G). A production line or gas lift line is located within the core, while the water injection line is located outside the core.