Abstract: The invention relates to a riser pipe section (1) comprising a main tube (2), at least one auxiliary line element (3) arranged substantially parallel to said tube (2), the ends of the main tube comprising connection means allowing longitudinal stresses to be transmitted and the ends of the auxiliary line element comprising linking means allowing longitudinal stresses to be transmitted, said linking means comprising at least one locking pin (14).

Abstract: A mooring leg connector (4) is configured for use with a mooring chain part (3) of a mooring leg extending up from the sea floor to moor a floating structure (1) to the seabed. The connector has an elongate tubular element (5) extending in the mooring leg direction and a latch mechanism (6) for fixation of the mooring chain part to the floating structure to be moored and preventing movement along the mooring leg in the direction of the seabed. The elongate tubular element has a passage for the mooring chain to pass through and includes at the top a double articulation axis including a roll articulation (7) and a pitch articulation (8). The roll and pitch articulations are coplanar.

Abstract: A mooring leg connector for use with a mooring leg (3) that has an upper portion with an axis, where the mooring leg (3) extends up from the sea floor, to connect a floating body (1) to the seabed. The mooring leg connector includes one part (20) fixed with regard to the floating body (1) and another part (30) which is movable with regard to the fixed part (20) from a first position to a second position. An offshore construction including such a mooring leg connector and a method to retract such a mooring leg connector when disconnected, are also described.

Abstract: Methods and systems for drilling subsea wells bores with dual-gradient mud systems include drilling the subsea well bore while employing a subsea pumping system, a subsea choke manifold and one or more mud return risers to implement the dual gradient mud system. When a well bore influx is detected, the well bore is shut in, and components determine if pressure control may be used to circulate the influx out of the well bore, the size of the influx, and how much the mud system weight will need to be reduced to match the dual gradient hydrostatic head before the influx reaches the subsea pump take point. The subsea pumping system, subsea choke manifold, and mud risers are isolated while the influx is circulated up one or more fluid passages in the drilling riser package using the surface pump, through the wellhead, and out the surface choke manifold.

Abstract: A push-up tensioner for maintaining a tensile force in a riser having an axis couples to a floating platform and maintains the tensile force while the riser tilts variably from the vertical. The tensioner includes a plurality of cylinders having a lower end pivotally coupled to the deck. The cylinders are substantially perpendicular to the deck in the running position and at an angle to the deck in the tensioning position. After running of the riser, a placement assembly moves the cylinders from the running position to the tensioning position. A tensioner ring is run on the riser proximate to an upper end of the cylinders, and the cylinders are then automatically coupled to the tensioner ring.

Abstract: The present disclosure provides an improved design for a pull tube sleeved stress joint and associated pull tube for managing stresses on a catenary riser for a floating offshore structure. The pull tube sleeve stress joint includes at least one sleeve surrounding a length of the pull tube with an annular gap between the sleeve and pull tube and a link ring therebetween. For embodiments having a plurality of sleeves, a first sleeve can be spaced by an annular first gap from the pull tube and coupled thereto with a first ring between the pull tube and the first sleeve, and a second sleeve can be spaced by an annular second gap from the first sleeve and coupled thereto with a second ring between the first sleeve and the second sleeve. Both pull tube and sleeves can be made with regular pipe segments welded together with regular girth welds.

Abstract: A system for interconnecting a floating rig and a riser assembly includes a rotating control device permitting pressurization of the riser assembly; and a sliding joint connected to the rotating control device, the sliding joint being longitudinally extendable and compressible while the riser assembly is pressurized. Another system includes a sliding joint including more than two telescoping sleeves, and the sliding joint being longitudinally extendable and compressible while the riser assembly is pressurized at the surface. An apparatus includes a sliding joint with multiple sets of telescoping sleeves, each set including at least two of the sleeves. Another apparatus includes a sliding joint with multiple radially overlapping seal assemblies.

Abstract: Disclosed is a method of fabricating and installing a riser tower structure, preferably in a welding chamber, and a welding chamber suitable for the method. The method includes fabricating sections of the riser tower structure at a site remote from the site of installation; transporting the sections of the riser tower structure to within the vicinity of the installation site; and assembling together the sections of the riser tower structure in the vicinity of the installation site. The welding chamber includes a plurality of guide means, each providing a guide for one of the elongate elements of the riser tower structure, and floats on the sea surface when in use.

Abstract: Methods and apparatuses for controlling the flow of hydrocarbons from a structure or conduit are provided. An engagement apparatus having a body with threads disposed on an end is lowered into a position suitable for engagement with the structure or conduit, the threads including a deformable material. Rotation of the apparatus to engage the threads with the structure or conduit deforms the material to form a wedge shape that provides a seal between the apparatus and structure or conduit, and resists removal of the apparatus from the structure or conduit. Additional conduits can be secured to the upper end of the apparatus, in combination with a valve. The valve can direct the flow of hydrocarbons from the structure or conduit to selected additional conduits, enabling vessels and/or containers to be removed and/or replaced without wholly ceasing the flow of hydrocarbons in a manner that could cause a buildup of pressure.

Abstract: An underwater buoy for hanging a duct between a sea bed and the surface, the buoy including a frame and a plurality of modular members mounted in the frame, the modular members extending between their two opposite modular-member ends, the frame including a longitudinal body for receiving the extended tubular duct, and retainers mounted on the body for maintaining the modular members substantially parallel to the body. The retainers include two retaining structures spaced from each other along the body. The retaining structures are maintained in a fixed position relative to each other in order to hold at least one modular member.

Abstract: A tube buoyancy can system for tensioning a top tension riser. In some embodiments, the system includes a tubular can coupled to the top tension riser and a pressurized gas system configured to selectably inject pressurized gas into the tubular can. The tubular can includes an enclosed upper end having at least one closeable opening therethough, an open lower end configured to allow seawater to flow freely into and out of the tubular can, and an inner surface extending therebetween. The inner surface is devoid of structural obstructions which substantially inhibit the free flow of seawater through the lower end. When the opening is open, the tubular can is ballasted by seawater. When the opening is closed and pressurized gas is injected into the tubular can, the tubular can is de-ballasted of seawater.

Abstract: A subsea completion testing tree (SCTT) for connection in a tubular string includes a lower tree portion having a control valve; an upper tree portion separably connected to the lower tree portion at a latch; a circulation valve connected with the upper tree portion; and a retainer valve connected with the upper tree portion between the circulation valve and the latch.

Abstract: This underwater-side structure is installed at the sea bed, and supports an above-water structure that is provided above the water, being provided with a first support member made of steel that extends from the sea bed to above the water and that has a first space therein; and a filling material being filled in a portion of the first space.

Abstract: An oil recovery system recovers oil released at the bed of a body of water. The system includes a fluid collector assembly positionable proximate to the bed of the body of water. The collector assembly has an open lower end to receive fluid and has an upper end coupled to a lowermost fluid transfer tube. Fluid transfer tubes are interconnected in a string between the lowermost fluid transfer tube and a vessel positioned to receive fluid transferred through the fluid transfer tube. A guide cable is anchored at the bed of the body of water to guide the fluid collector assembly and the fluid transfer tubes to the bed. A lift cable selectively lowers the fluid collector assembly and the fluid transfer tubes to the bed. Fluid entering the collector assembly rises to the water surface via the transfer tubes.

Abstract: A method and apparatus for buoyancy distribution along a substantially vertical submarine structure (100), the structure being provided with multiple modules (110), slidably mounted to the structure such that when vertically deployed at sea the modules are may adjust their positions along the structure by sliding, the force of each module acting upon the module above it rather than locally along the structure, resulting in the cumulative force (460) from the modules acting substantially against the top of the structure. Forces between modules may be evenly distributed by use of compliant intermediaries (310).

Abstract: Disclosed is a riser tower structure including a plurality of elongate objects. The riser tower structure is provided with blocks, preferably of buoyant material, along at least part of its length. The blocks provide the riser tower with a substantially circular cross-sectional profile, wherein one or more strakes are provided on the outside of the blocks. The strakes in a main embodiment are helical. Also disclosed is a corresponding method of constructing such a riser tower structure.

Abstract: A method of installing a subsea structure, such as a hybrid riser tower, is disclosed. The riser tower includes a main portion and a buoyancy portion. When installed, the riser tower extends substantially from the seabed towards the surface with the buoyancy portion attached at a top end. The method includes taking the riser tower to an installation site in a substantially horizontal configuration with the main portion containing a first fluid and the buoyancy portion containing a second fluid, the second fluid being more dense than the first fluid. Then, tilting of the riser tower is performed such that it takes a substantially vertical configuration by allowing the first fluid in the elongate portion to interchange with the second fluid in the buoyancy portion. Also disclosed is a suitable apparatus for performing the method.

Abstract: Flexible riser, comprising a length of a flexible pipe with an upper end, a bend restrictor and a termination for hanging up on a vessel, a floating installation or a platform, distinguished in that the bend restrictor in the upper end is connected to an adapter pipe extending from a lower end at the bend restrictor to an upper end, to an end coupling to which the upper ends of both the flexible pipe and the adapter pipe are fastened, the flexible riser extending through the bend restrictor and the adapter pipe and the end connection comprising a means for hanging up at deck level of the vessel, the installation or the platform. Method for pulling-in and hanging up of the flexible riser.

Abstract: This patent application applies to an Active Motion Compensation system for use during intervention or other work on subsea wells, pipelines or other structures. It could be used on existing floating production platforms such as Tension Leg Platforms (TLP) and Spar structures where intervention work including Coiled Tubing, Slickline, Electric Line, Wireline, as well as snubbing or Hydraulic Workover activities are being utilized. It could also be deployed over the side of or through the moon pool of a vessel without the need of any other compensation device.

Abstract: Disclosed is a riser comprising a plurality of pipelines. In one example there are three such pipelines, extending from the seabed toward the surface and having an upper end supported at a depth below the sea surface, wherein, in one embodiment a first of said pipelines acts as a central structural core, the other pipelines being arranged around said first pipeline. In another embodiment three pipelines are arranged around a structural core. In each case, the first of said pipelines may be a fluid injection line, said other pipelines being production lines. Also disclosed is a riser having buoyancy along at least a part of its length, said buoyancy resulting in said riser having a generally circular cross-section, the circumference of which being non-contiguous. Methods of installing such risers are also are also described.

Abstract: Dual gradient drilling may be performed by anchoring drilling tubulars from a drilling ship on the seabed. The drilling tubulars may include an inline pump for pumping mud through another set of tubulars that actually drill the well. Then dual gradient drilling may be instituted by controlling the pressure by controlling the operation of the pump.

Abstract: A system for capturing oil leaking from an underground well includes an elongate hollow tube which is deployed vertically in the water with its open lower end located above the oil well. A system for securing the tube in the desired location where it captures the maximum amount of leaking oil includes an adjustment system which allows the tube to be moved transversely once it is in place. A method is provided for erecting the tube and anchoring it at the desired location above the leaking well.

Abstract: A riser installation method including the steps of providing a first vessel situated over a hydrocarbon well, supporting a hydrocarbon transfer duct from the first vessel by a first end that is attached to a lowering device on the first vessel, and attaching a second end of the hydrocarbon duct to a second vessel, at a position near the first vessel. The method also includes the steps of lowering the transfer duct, increasing the distance of the second vessel from the first vessel, pulling the transfer duct until the second vessel is near the third vessel, contacting a section of the transfer duct with the sea bed, displacing the second end of the transfer duct from the first vessel, returning the second end of the transfer duct to the mooring position, and bringing the second end of the hydrocarbon transfer duct in fluid communication with the third vessel.

Abstract: During an Extended Well Test or Early Floating Production at an offshore hydrocarbon production site, where oil and gas hydrocarbons are produced by a production vessel, applicant stores the natural gas as pressured gas in a storage tank and occasionally transfers the pressured gas to a shuttle vessel which carries the gas to a site where it is used, as by pumping it into a natural gas pipeline. The transfer of natural gas to the shuttle can be accomplished by pumping it through a conduit extending between the vessels to a second tank on the shuttle, or can be accomplished by moving a gas-filled tank on the production vessel to the shuttle.

Abstract: The invention provides a marine riser apparatus (1) for use in the production of hydrocarbons from offshore wells and an associated method of installation of the apparatus at sea. The riser tower comprises rigid pipelines arranged in a riser tower bundle (2) and extending from a wellhead on the seabed (4) to a point below the sea surface where they are connected to flexible jumpers (3) which extend from the tower structure to connect the tower structure to a surface vessel or platform (5). The riser apparatus further comprises a buoyancy device (7) attached to the riser tower bundle, such that the buoyancy device is located above and exerts a buoyancy force on the riser tower, the buoyancy module also supporting an intermediate section of at least one of the jumpers.

Abstract: A riser tensioner configured to apply a tension to a riser. The riser tensioner includes a frame configured to be fixedly attached to the riser; plural cylinder assemblies spaced around the riser, each cylinder assembly having a cylinder and a piston configured to slidably move inside the cylinder, the piston being configured to connect to the frame; a guide roller support stationarily mounted to and extending from the frame; at least one bearing fixedly attached to the guide roller support; and a guide member configured to be in rolling engagement with the at least one bearing as the cylinder moves relative to the frame.

Abstract: A valve assembly is described for containing an oil spill caused by a defective blowout preventer. The valve assembly may include a hollow cavity having a floor, a ceiling and a wall, and a valve that protrudes through the ceiling and the floor of the hollow cavity. The hollow cavity may be configured to be reinforced by filling the hollow cavity with cement. The valve assembly may have a cylindrical geometric configuration. The valve may be configured to be maintained in an open position while the valve assembly is lowered below a surface of an ocean. The valve assembly may be positioned above a blowout preventer located on a floor of the ocean.

Abstract: An apparatus to restrain a riser tensioner of an offshore drilling rig includes a restraint cone configured to fit within hydraulic cylinders of the riser tensioner, a hoist configured to extend and retract the restraint cone, and a tension member extending from a lower end of the restraint cone, the tension member configured to engage a lower end of the riser tensioner and maintain a wedging action between the restraint cone and the hydraulic cylinders.

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 axial movement of the hull.

Abstract: A system, program product, and method for monitoring and managing a plurality of marine riser assets is provided.

Abstract: An improved riser system which comprises a connector for connecting conduits and a mooring system for mooring the connector to the floor of a body of water. The improved riser system also comprises a buoy system for supporting the connector. The buoy system is configured to provide a fixed buoyancy for the connector, the mooring system and at least a portion of the conduits and for providing variable buoyancy for placement of the connector at a predetermined water depth.

Abstract: A sea vessel exploration and production system is provided, wherein the system includes a drilling station formed from at least one section of a first sea vessel hull; and a docking station, which is also formed from at least one section of a second sea vessel hull. A mooring system suitable for connecting the drilling station to the docking station is also provided. Means for anchoring the vessels to the seafloor, and for attaching them to turret buoys, are also considered. Various exploration and production packages, as well as equipment required to deploy and control a self-standing riser system in either deep or shallow waters, are also described.

Abstract: Disclosed is a riser tower structure including a plurality of elongate objects. The riser tower structure is provided with blocks preferably of buoyant material, along at least part of its length. The blocks provide the riser tower with a substantially circular cross-sectional profile, wherein one or more strakes are provided on the outside of the blocks. the strakes in a main embodiment are helical. Also disclosed is a corresponding method of constructing such a riser tower structure.

Abstract: A system for and method of limiting and controlling the unintended subsurface release of an exploration or production riser system is provided including one or more means for anchoring the riser or casing stack at one or more pre-determined points upon the length of the riser, and/or on the housing of an associated buoyancy chamber or the like, and/or on a particular portion of the riser as dictated by the operational environment, and/or on an anchor portion secured in the sea floor; and a network of restraining members disposed on the anchoring means. A lower anchoring portion includes one or more anchors disposed in communication with a wellhead, or with the sea floor or below the sea floor mud line, or with a well casing portion. A network of restraining members forms an essentially continuous connection from the buoyancy member portion to said bottom anchor portion.

Abstract: Disclosed is a buoyancy device for tensioning an elongate vertical (or quasi vertical) subsea structure at a point below the sea surface, anchored at its bottom. The device comprises as its main buoyancy elements a plurality of hollow elongate objects, and further comprises at least one auxiliary buoyancy element comprising a solid buoyant material. Ideally, the solid buoyant material provides enough uplift to maintain the device afloat should the main buoyancy elements be flooded. A riser apparatus comprising such a buoyancy device is also described.

Abstract: Apparatus and a method are disclosed for venting gas from an annulus region of a flexible pipe. The method includes the steps of depressurising a bore region of a flexible pipe and via at least one vent flow fluid communication path, venting gas from an annulus region of the flexible pipe into the bore region.

Abstract: An apparatus and method for containing oil from a deep water (greater than 1,000 meters) oil well is disclosed herein. The apparatus has an anchor section, a plurality of riser sections, an upper section and a flow tube. A pressure within the apparatus is equal to a pressure outside of the apparatus to prevent collapse of the apparatus, and to prevent crystallization. Oil is suctioned from the interior of the apparatus through the flow tube to a surface of the ocean.

Abstract: A connector (10) for releasable connection between an anchorage in the form of a female part (1) arranged on a floating means and a male part (2) formed at the end of a retrievable umbilical (3) provided with a bend stiffener (4) is disclosed. The male part (2) comprises a mandrel body (5) having a pulling head (6) for connection to a pulling means at one end and the umbilical (3) at the other end. The male part (2) comprises a sleeve formed body (7) that is fixed to the mandrel body (5) by shearable elements (8). The bend stiffener (4) is fixed directly to the sleeve formed body (7) and is designed for abutment against and parking together with the bend stiffener (4) within the female part (1) while the remaining part of the male part (2) including the umbilical (3) is designed to be pulled further up through the female part (1) for fluid communication and connection on a floating means or a vessel.

Abstract: An apparatus and method for containing oil from a deep water (greater than 1,000 meters) oil well is disclosed herein. The apparatus has an anchor section, a plurality of riser sections, an upper section and a flow tube. A pressure within the apparatus is equal to a pressure outside of the apparatus to prevent collapse of the apparatus, and to prevent crystallization. Oil is suctioned from the interior of the apparatus through the flow tube to a surface of the ocean.

Abstract: A multi-tiered self-standing riser system includes one or more intermediate buoyancy chambers configured to provide an upward lifting force on strings of associated riser assemblies. The intermediate chambers have either an open-bottomed or closed container design. The chambers can further include an auxiliary buoyant material designed to either mix with or contain pressurized fluids injected into the chambers. The self-standing riser system further includes a lower riser assembly affixed to a primary well-drilling fixture. The system also includes an upper riser assembly and one or more additional buoyancy chambers disposed in either direct or indirect communication with one another, as well as with drilling, production and exploration equipment as required by associated operations.

Abstract: A riser system for offshore oil and gas production for communicating systems located on the seabed with floating facilities suitable for accommodating floating facility static and dynamic offsets and motions. The riser system comprises a riser extending from the seabed to a floating facility that is supported by a hybrid support system.

Abstract: A free standing riser system includes a riser, a subsea intervention unit, and an umbilical line. The riser includes interconnected joints linked to one another, a lower-end of the riser being coupled to a wellhead and an upper-end of the riser enclosed in a buoy assembly, including a terminal, the riser being maintained in an erect, substantially vertical position. The subsea intervention unit is provided above the riser, and includes three connections: one connection to the terminal of the riser, one connection to a flexible jumper that is connected to a FPU, and one connection that provides a vertical conveyance to an intervention rig.

Abstract: A system comprising a surface installation in position above a plurality of subsea wells disposed within the watch circle of the surface installation. A plurality of flowlines directly couple at least one of the plurality of subsea wells to the surface installation. A control station, a hydraulic power unit, and an injection unit are disposed on the surface installation. A distribution body is disposed on the seafloor and is coupled to each of the control station, hydraulic power unit, and the injection unit via one or more umbilicals. A first wellhead component is disposed on one of the subsea wells and is coupled to the distribution body via one or more flying leads that provide electrical, hydraulic, and fluid communication. A second wellhead component is disposed on another one of the subsea wells and coupled to the distribution body via one or more flying leads that provide electrical, hydraulic, and fluid communication.

Abstract: A tendon top connector for a moored, floating structure such as a tension leg platform, a tension leg buoy or the like has a bowl-shaped extension on the member which transfers the tension of the tendon to the flex connector. A dome-shaped structure at least partially surrounds the bowl-shaped extension but is spaced apart from it to permit at least some rotational movement of the connector. The dome-shaped structure may be attached by clamps or other mounting means to a flange member affixed to the tendon porch. This arrangement provides a load path when the tendon top connector is reverse loaded that extends from the tendon length adjustment joint, through slips, through the bowl-shaped extension, through the dome-shaped structure, through the segmented clamps, and finally into a flange attached to the tendon porch. In this way, detachment of the tendon top connector is prevented if a reverse load is applied such as may occur during extreme metocean conditions.

Abstract: An apparatus and method are provided for performing an intervention in a flexible riser that extends between topside and subsea locations. The method generally includes providing a composite tube and inserting a leading end of the composite tube into the flexible riser so that the composite tube extends through the flexible riser from the topside location toward the subsea location. The composite tube can be configured to deliver a material into the flexible riser, e.g., to remove a blockage formed in the riser.

Abstract: A pontoonless tension leg platform (TLP) has a plurality of buoyant columns connected by an above-water deck support structure. The design eliminates the need for subsea pontoons extending between the surface-piercing columns. In certain embodiments, the buoyancy of the columns is increased by the addition of subsea sections of increased diameter (and/or cross-sectional area) to provide the buoyancy furnished by the pontoons of the TLPs of the prior art. A pontoonless TLP has a smaller subsea projected area in both the horizontal and vertical planes than a conventional multi-column TLP of equivalent load-bearing capacity having pontoons between the columns. This reduction in surface area produces a corresponding reduction in the platform's response to ocean currents and wave action and consequently allows the use of smaller and/or less costly mooring systems.

Abstract: A removal impact cover (14) for a marine riser buoyancy module (10) has an arcuate shape with an open face (21). The cover (14) has a number of recesses (18) arranged to engage with recesses (22) on the module (10). The recesses (18) each contain an aperture (20) and the recesses (22) each contain an aperture (23). The cover (14) and the module (10) are engaged by fastening means preferably extending the apertures 20 and 23. More preferably the engaged cover (14) is spaced from the module (10) to reduce direct transmission of forces to the module (10).

Abstract: A technique facilitates formation of connections between compliant tubular members and subsea facilities. A compliant tubular member is deployed to a subsea location in a manner that arranges the compliant tubular member in a curvilinear shape. The distal end of the compliant tubular member is drawn down into proximity with the subsea facility and then moved horizontally into alignment with the subsea facility. Subsequently, the distal end is lowered into engagement with the subsea facility without being detrimentally affected by motion of an upper end of the compliant tubular member.

Abstract: The present invention relates to overpressure protection systems and methods for use on a production system for transferring hydrocarbons from a well on the seafloor to a vessel floating on the surface of the sea. The production system includes a subsea well in fluid communication with a turret buoy through a production flowline and riser system. The turret buoy is capable of connecting to a swivel located on a floating vessel. The overpressure protection device is positioned upstream of the swivel, to prevent overpressure of the production swivel and downstream components located on the floating vessel. The device may include one or more shut down valves, one or more sensors, an actuator assembly, and a control processor.

Abstract: An improved subsea manifold system that is capable of being used in an early production system for producing hydrocarbons from a plurality of wells from a common riser system. The subsea manifold is able to control the fluid from a multiple of subsea wet-tree wells while at the same time giving the operator the option to isolate production from a single subsea well for production evaluation. The subsea manifold also includes a pigging loop which enables efficient pigging of the flowline(s) of the early production system.