Abstract: A bottom connector for the tendon of a tension leg platform uses a latch ring with an outer profile to engage a mating profile in a receptacle on the sea floor. The latch ring moves radially within a housing, relative to the receptacle, between an engaged position and a retracted position. The latch ring engages the receptacle by lowering the connector into the receptacle below the mating profile and then lifting it until the latch ring locks into the receptacle. The latch ring disengages the receptacle by lowering the connector beyond a recess located below the mating profile and then lifting the connector out of the receptacle. As the connector is lifted above the recess, a retaining ring is actuated by the recess to retain the latch ring in its retracted position.

Abstract: A mooring unit and method of retrofitting a mooring unit are provided. Certain existing combination mooring units, of the type having two wire rope drums and two wildcats, are experiencing increased winch drive train component stress levels during operation when used in water deeper than they were designed for. Existing units are modified by providing left and right twin drum traction winch assemblies and additional winches. The existing wire rope drums are discarded, or reused with the additional winches. The additional winches are preferably mounted below the mooring unit. The twin drum traction winch assemblies, which deliver a constant winch pull force, are vertically mounted within the support flanges where the removed wire rope drums were previously mounted, without any modification to the support flanges.

Abstract: A fairing system is disclosed for protecting multiple, parallel, bundled but separate cylindrical elements deployed in offshore applications. The fairing system deploys a plurality of elongated fairing surface elements foldable about an axis with a connection system joining the elongated edges of the fairing surface elements in a folded manner about the axis. A plurality of thrust bearings are orthogonally connected across the fairing surface elements at each axial end and an axially extending circular rotational surface is defined by the interior of each of the folded fairing surface elements and a transverse edge of the thrust bearings connected thereto. This rotational surface has a diameter which circumscribes the multiple bundled cylindrical elements. A plurality of clamps interconnect the bundled, cylindrical elements and a bearing collar on the axial ends of the clamps is provided to receive the thrust bearings of the axial ends of the fairing elements.

Abstract: In a tension-leg mooring system a production platform supporting one or more decks above the water surface for accommodating equipment to process oil, gas, and water recovered from a subsea hydrocarbon formation is mounted on a single water surface piercing column formed by one or more buoyancy tanks located below the water surface. The surface piercing column includes a base structure comprising three or more pontoons extending radially outwardly from the bottom of the surface piercing column. The production platform is secured to the seabed by one or more tendons per pontoon which are secured to the pontoons at one end and anchored to foundation piles embedded in the seabed at the other end.

Abstract: The present invention relates to an apparatus and to a method for facilitating the connection of underwater flexible risers coming from the sea bed at any point located above the sea surface on a surface structure. Two principal components are used, namely a guide device (1,51), and a connection device (8), which is connected to an underwater flexible riser (14) which it is desired to connect to the structure.

Abstract: In a device for oil production at great depths at sea, production/drilling equipment is provided on a floating structure (2) at the surface of the sea, such as a platform structure or a vessel structure, for instance a ship, which is connected to a flotation unit (5) under water, which is anchored with a tension mooring (4) to the sea floor and with a riser system (6) which extends upwardly to the deck (9) of the structure. The structure (2) is equipped with an open vertical frame construction (8), such as a trusswork projecting downwardly in the water, the lower part of which forms a guide (17) and protection for the flotation unit (5). The rigid risers (4) from the sea bed continue up with the system (6) through the flotation unit (5) and further, enclosed by the frame (8) up to the level of the deck (9) above the water surface, where they are terminated in a Christmas tree device (7), or a manifold. A flexible riser system (11) extends from the valve arrangement (7), e.g.

Abstract: A pumpskid comprises a frame adapted for connection to a remotely operated vehicle for positioning thereby. A male connector mounted on the frame is adapted for engagement with the suction port on a suction anchor. Clamping apparatus is provided for securing the male connector in engagement with the suction port of the suction anchor and thereby clamping the pumpskid in engagement with the suction anchor. A pump mounted on the frame is connected in fluid communication with the male connector by piping sections which include a port open to the surrounding sea. Valves and valve actuators are provided for causing the pump to cause water flow out of or into the suction anchor, as required.

Abstract: A stand-off assembly to attach to a cylindrical support member. The stand-off assembly includes a first component having a first arcuate portion adapted to conform to an outer surface of the cylindrical support member. The first component has a first attachment upright. A second component has a second arcuate portion adapted to conform to the outer surface of the cylindrical support member and also includes a second attachment upright. The second component is connected to the first component with a hinge connection. The first and second arcuate portions in combination extend substantially around the cylindrical support member and the first and second attachment uprights are parallel but separated from each other when the first and second arcuate portions are extended substantially around the cylindrical support member.

Abstract: A segmented ring forms a set of latches for a tendon top connector on a floating platform. The latches reside in a housing and have either a groove or thread profile on an upper internal surface. The grooves interface with a mating groove profile on the tendon. The latches rotationally pivot backward and forward from the outer portion of the bottom surface. When the latches are forward, the profile in the internal surface engages the mating profile of the tendon top joint. When the latches are swung out, these profiles clear and permit the top joint to pass through the connector. Retraction of the latches is provided by application of force on the inside surface of an annular extension on the outer portion of the latches. This force can be provided by a variety of actuators. This top connector allows for passive dynamic engagement of the connector to the tendon top joint. When the latches are permitted to move inward, contact is made with the mating profile on the tendon top joint.

Abstract: Vertical movement of a floating marine platform is reduced by tendons extending from the platform to anchors on the seabed. A final tension adjustment to equalize the load on all of the tendons is made by a respective tension adjustment mechanism incorporated into the top connector of each tendon. The tension adjustment mechanism includes a split load ring assembly having an upper ring and a lower ring. The upper ring and the lower ring abut each other at respective complementary surfaces. Each surface has a series of serrated ramps. A rotation of one ring with respect to the other causes the upper ring to climb over the lower ring to thereby increase the tension in the tendon. Rotation of the upper ring with respect to the lower ring, for example, is achieved by a motor driven gear ring.

Abstract: A stress relieving joint for use with riser pipe in floating systems wherein a vessel is subject to variable motion caused by wind, currents, and wave action. The riser pipe has one end connectable to the sea floor and an upper portion adapted to pass through a constraining opening at the bottom of the vessel. A ball joint and socket assembly is removably attached to the keel at the constraint opening. A sleeve is attached at substantially its midpoint in the ball joint. Riser pipe received in the sleeve is provided with wear strips that reduces the rate of reduction in wear surface diameter.

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

Abstract: The connection between a surface terminus for subsea production risers and a surface collection vessel is facilitated by a connection which utilizes slack loop flexible jumper hoses between the surface terminus of the subsea risers and a swivel coupling located on the surface vessel.

Abstract: A surf stand which can be used for surf fishing, life guard stands, and other marine functions. The lightweight stand can be easily manufactured and assembled from common, inexpensive materials. The surf stand features a unique construction which permits the application of suction forces within the legs to help set the stand firmly in the bottom soil or sand for stability and safety. The unique construction also permits pressurization of the legs to help dislodge them from the bottom when relocation or removal is desired.

Abstract: A controlled-pressure multi-cylinder riser tensioner has a plurality of preferably six control-cylinder units (1) with proximal ends (2) attached pivotally to a bottom surface of an operational floor (3) and distal ends (5) attached pivotally to a riser-tensioner ring (6). Pressure lines (20, 38) in communication with opposite ends of the control cylinders lead to sources of pressure (46, 47, 48, 52, 53, 62, 63) that are separately controlled. Stroke length of the control-cylinder units is typically 50 feet. Projection of the control-cylinder units downwardly into a moon pool (9) avoids their obstruction of work space on an operational floor (3) of a vessel (4). Positioning pneumatic and hydraulic machinery (10) below deck with tubing leading to the control cylinders lowers center of gravity for marine stability. An over-capacity for tensioning the marine riser with a portion of the control cylinders inactive or incapacitated increases reliability.

Abstract: A shallow draft floating offshore drilling/producing structure. The structure is formed from a buoyant hull on which one or more modules or decks may be placed to support process equipment, a drilling rig, utilities, and accommodations for personnel. Drilling and/or producing is accomplished through a center well in the hull. The hull includes fixed ballast, an oil storage area, and voids and variable ballast for offsetting the lighter weight of the stored oil. The hull is designed to have a relatively small water plane area. The hull is also designed to have roll and pitch periods that are detuned from waves in the area that the hull is to be installed.

Abstract: A bottom supporting construction for a leg end of a displaceable jack-up platform including a block-shaped leg end part and a supporting element which can be positioned and anchored on a bottom under water and which is provided with a supporting face for a leg end, while a resilient sealing collar, closed upon itself, and a buffer, which in unloaded condition have a height less than that of the sealing collar, are arranged so that when the leg end comes to rest on the supporting element, a space closed off from the environment is formed between that leg end, that sealing collar and the supporting face, and closable discharge is present for enabling water to be discharged from that space. If so desired, upwardly extending support can be arranged on the supporting face, which receive the leg end at least locally with relatively close abutment, so that that support can support the leg end in horizontal direction.

Abstract: An offshore fluid transfer system (10) is provided, of the type that includes a riser (32) having an upper end (34) connected through a universal joint (36) to a turret (22) on a vessel and having a lower end (36) anchored by catenary chains (40), and that also includes hoses (70, 71) extending from a base (50, 58) on the seafloor to the turret on the vessel, which avoids the need for a complicated hose structure to pass fluid across the universal joint. A fluid coupling (73) near the bottom of the turret, which is widely spaced from the universal joint, connects to a hose that extends from the fluid coupling in a sinuous path down to the seafloor base. The long length of hose, enables it to bend when the vessel drifts, to avoid excessive hose tension or riser contact during such vessel drift. A riser connector (102) can be operated to disconnect the riser from the turret so the riser can sink. The fluid coupling can include a fluid connector (100) which can separately disconnect the hose from the turret.

Abstract: A floating platform comprising in combination a semisubmersible vessel (40) having two or more pontoons, buoyant columns upstanding from those pontoons and a deck supported on the columns (the semisubmersible vessel being a kind known per se); and a raft (41) comprising a hull portion and two or more buoyant caissons arranged so that the raft is capable of floating in a stable configuration with the hull portion of the raft submerged to such a depth that the semi submersible vessel (40) can float over the hull portion and with only the buoyant caissons piercing the water surface, in which the pontoons of the semisubmersible vessel (40) are secured to upper surfaces of the hull of the raft (41).

Abstract: An offshore well is stabilized by at least three cables connected on one end to hydraulically powered cable tensions on the well casing at a location substantially below the surface of the body of water in which the well is located and on an opposite end to a respective anchor pile on the bottom body of water. The cables are equally tensioned by the hydraulically powered cylinder and are subsequently retained in taut condition by mechanical retainers.

Abstract: A passive riser tensioner apparatus for tensioning riser pipes on floating platforms and tension leg platforms utilizes one or more elongate elastic tensioning elements connected at top and bottom ends to the upper end of a riser pipe that are capable of being axially stretched. Each tensioning element has a threaded length adjustment rod and tension preload nut at its top end which adjusts the axial length to produce a predetermined preload tension force in the tensioning element between its connection to the riser pipe. A riser support collar slidably received on the length adjustment rod and riser pipe upper end is configured to be supported on the deck of the platform and allow axial movement of the riser pipe. A tension locking nut on the length adjustment rod releasably engages the length adjustment rod with the riser support collar when it is supported on the deck.

Abstract: A method of providing a tendon guide surface to an installed pile is disclosed in which a tendon foundation guide cone assembly having a tendon guide surface is attached to a lowering unit and lowered to the pile. The tendon foundation guide cone assembly is then attached to the installed pile and released from the lowering unit. A tendon foundation guide cone assembly and a method for securing a tendon to the ocean floor are also disclosed.

Abstract: A protective sleeve protects a riser that extends between a subsea wellhead and a floating vessel. The protective sleeve has less resistance to bending than the riser so as to allow the riser to bend normally due to normal movement of the vessel. The stiffness of the protective sleeve augments the stiffness of the riser only if the acceptable level of bending is exceeded. The protective sleeve is made up of at least three segments that are articulated together to facilitate bending.

Abstract: A floating caisson for offshore drilling and production that includes means for increasing the natural period of the caisson and reducing heave, pitch, and roll without increasing the overall length of the caisson. The caisson is self buoyant by means of buoyancy tanks and is held in position by mooring lines. The caisson has a center well through which drilling and/or production risers pass. One or more plates extend radially from the caisson below the water surface. The plates provide additional mass and resistance to environmentally induced motions and thus increase the natural period of the caisson beyond the periods of maximum wave energy. This allows the caisson to be designed with a shallower draft than a caisson without the plates that would normally be used in deep water.

Abstract: A subsea system comprises a central template that is piled into the seabed and carried wing modules that are connected to the template by hinges. This allows the template to be deployed and the wing modules attached subsequently or for the wing modules to be folded upwardly into a collapsed disposition as the template is deployed. In either case, the template can be deployed through the moonpool of a vessel and does not require a heavy lifting barge. An example of a module usable with the template is a hinge-over guidebase which can allow the commencement of drilling of a well while a manifold and christmas tree are being constructed for subsequent attachment. Thus, installation of the system is easy and drilling of the well can commence quickly.

Abstract: An offshore platform for supporting a platform deck in deep water. A buoyant base is submerged below the water surface and is retained with base tendons to a foundation on the sea floor. The buoyant base is attachable to the mooring tendons of a tension leg vessel positioned above the buoyant base. The buoyant base can be selectively ballasted to control the tension in the base tendons. Additional buoyant bases and connecting tendons can extend the depth of the total structure beyond depths possible with conventional tension leg structure technology. Mooring lines can be connected between the buoyant base and the sea floor to limit lateral movement of the buoyant base. The buoyant base esentially creates a submerged foundation which reduces the required length of a conventional tension leg platform. The tension leg platform can be detached from the buoyant base and moved to another location.

Abstract: A deep water pile and installation and removal method that eliminates the need for underwater hammers or pile drivers. The pile is a hollow tube that is open at the lower end and provided with a fitting at the upper end for attachment to a lowering pipe. The fitting at the upper end also for fluid communication between the lowering pipe and the pile. Injecting air into the lowering pipe draws water from the lowering pipe and pile. This creates a hydrostatic pressure differential whereby the greater pressure on the outside of the pile head forces the pile into the sea floor. Removal of the pile may be accomplished by injecting high pressure water into the pile through the pile head. The high pressure water injection aids in overcoming the hydrostatic pressure on the outside of the pile head.

Abstract: Modular floating structures suitable for supporting offshore oil drilling and production platforms may be fabricated utilizing a Y-shaped joint interconnecting plural legs of a space frame. The space frame may be made up of plural frame members where each corner of the frame includes a Y-shaped joint. Stable offshore floating structures for drilling and production platforms may utilize the integral space frames in a truncated dodecahedral, inverted pyramid or tetrahedral configuration. The Y-shaped joint may be formed of three channel members each having opposed legs which may be secured to the opposed legs of the other channel members in a back-to-back or face-to-face configuration to form the Y-shaped joint. The channel members may be fabricated of flat plate folded and cut along predetermined lines to form the channel members. If the channel members are secured to each other face-to-face, they may form hollow flotation chambers suitable for use with the floating structures.

Abstract: A deep water support platform, suitable for use as a hydrocarbon exploration or production facility in very deep waters, and a method of constructing the same are shown. The platform is positioned on top of one or more flexible, buoyant piles made of large diameter, high strength steel tubing. A watertight bulkhead is located within each pile and the portion of the pile below is filled with seawater, while the portion above the bulkhead is substantially empty and in communication with the atmosphere. The bulkhead is positioned to cause the pile to have a predetermined net buoyancy so that the portion below the bulkhead, which is anchored to the seabed, is in tension. Adjacent piles are joined at their tops by rigid bending members to prevent rotation of the tops under wind and wave conditions, so that the platform will remain level.

Abstract: A parasite mooring system is disclosed for restraining a compliant platform with respect to an auxiliary vessel. The parasite mooring system includes a parasite mooring line, a platform termination securing the parasite mooring line to the compliant platform; and a grip securing the parasite mooring line to a mooring line of the auxiliary vessel passing beyond the compliant platform. Another aspect of the present invention is a method for conducting offshore well operations in which a semisubmersible vessel is brought adjacent a compliant platform such that at least one mooring line of the semisubmersible vessel extends past the compliant platform and a parasite mooring line from the compliant platform is connected to the mooring line of the semisubmersible vessel.

Abstract: A compliant tower is disclosed having a foundation connected to a wide-bodied compliant framework with a plurality of vertically extending legs a minimum of horizontal bracing. The compliant framework is configured to maintain a substantially wide, open riser suspension corridor. A topside facility is supported by the compliant framework and a plurality of freely suspended production risers extend through the riser suspension corridor from the vicinity of the topside facility to communicate with the reservoir. These production risers are spaced to provide clearance to prevent riser interference in response to normal flexure of the compliant tower and normal environmental loads on the risers. A riser support assembly is configured to accomodate relative motion between the risers and the topside facility, supporting the production risers in tension near their upper ends to provide the principal load transfer between the riser and the compliant framework.

Abstract: A riser tensioner system for applying a substantially constant tensioning force to a riser and allowing a floating platform to move within a given range along a longitudinal axis of the riser. The system includes a plurality of tensioner assemblies each of which are coupled to the riser and to the platform. Each of the tensioner assemblies includes an upper member, a lower member, a connecting member coupled to the upper and lower members, and intermediate members coupled to the upper and lower members at a point intermediate the ends of the upper and lower members. At least one of the upper member, the lower member, and the intermediate members are adapted to provide a constant tensioning force. The arrangement of the upper member, lower member, connecting member, and intermediate members further provide a linkage whose centerline in angularly spaced from the longitudinal axis of the riser by a substantially constant amount throughout the range of motion of the linkage.

Abstract: A tendon cluster array is disclosed for tethering a superstructure of a tension leg platform to an ocean floor in which a plurality of tendons are anchored to the ocean floor at their lower ends with a substantially planar, horizontally disposed tendon bracket receiving the upper ends. A tendon bracket connection pivotally secures the tendon bracket to a downwardly disposed surface of the superstructure.

Abstract: The present invention is a deepwater compliant platform that has enhanced dynamic characteristics by virtue of its wide stance, eliminates conventional conductor drivepipe guides and supporting framework, and reduces the net material requirements with a substantially open interior permitted in the absence of the conductor guides. This utilizes the wide body stance to accommodate a wide riser suspension corridor through the open interior thereby allowing suspended risers to be spaced apart sufficiently to avoid interference in response to normal tower motions.

Abstract: A robot comprised of a platform, tendons and a control system. The platform contains proximal reels for the storage, retraction and extension of the tendons, with each tendon having a reel. The distal ends of the tendons are anchored at separate locations. The work space of the robot is primarily determined by the location of the tendon anchors, although it can be expanded by having pairs of tendons cross each other in between the platform and their distal anchor points. The platform is translated and rotated in the work space by controlling the lengths of the tendons extending from their respective reels. A master computer located on the platform controls each reel and coordinates their actuation. When used with at least six tendons and reels, the platform has six degrees of freedom: translation in three axes and rotation about each of the foregoing three axes. Numerous types of end effectors can be mounted on the platform, thus enabling the robot to perform a wide variety of tasks.

Abstract: A single point mooring system with at the bottom end thereof connecting points for risers which supply products from deep-water wells, said connecting points being arranged at the outer circumference of a bottom structure with enlarged diameter, each connecting point having a short vertical conduit and being arranged to guide therethrough a hookup wire in combination with a sealing element to be coupled to the upper end of a riser to hoist this end to the vertical conduit.

Abstract: A new pile assembly and process are disclosed. A pile cap is attached to a pipe pile. A partition is installed below the pile cap creating an air chamber between them that is at surface atmospheric air pressure. An external conduit containing a valve that is closed connects the pile's interiors above and below the partition. The pile is driven into the ocean floor filled with entrapped sea water below the partition so that little or no soil core is generated. After the clay soils adjacent to the pile have regained their strength, the valve is opened. A small amount of sea water expands into the air chamber. The pressure on both sides of the partition and the bottom of the pile cap is now slightly above surface atmospheric air pressure. It is the downward force of hydrostatic pressure on top of the pile cap that increases the tension capacity of the driven pile. In deep water hydrostatic pressure is substantial, constant and cheap.

Abstract: A tension leg platform system includes a relatively small platform (12, FIG. 3 ) and relatively low capacity tendons (16), despite providing sufficient tension to risers (34) that carry hydrocarbons from seafloor wells to the platform. With the platform floating at the sea surface and held in position by the tendons, seafloor wells can be connected through risers to a side of the platform, with the tension of each riser compensated by adding buoyancy to the corresponding side of the platform, as by using pressured air (at 100) to blow water out of a platform compartment (94).

Abstract: A deep water offshore apparatus for use in oil drilling and production in which an upper buoyant hull of prismatic shape is provided with a passage longitudinally extending through the hull in which risers run down to the sea floor, the bottom of the hull being located at a selected depth dependent upon the wind, wave, and current environment at the well site, which significantly reduces the wave forces acting on the bottom of the hull, a frame structure connected to the hull bottom and extending downwardly and comprising a plurality of vertically arranged bays defined by vertically spaced horizontal water entrapment plates and providing open windows around the periphery of the frame structure, the windows providing transparency to ocean currents and to wave motion in a horizontal direction to reduce drag, the vertical space between the plates corresponding to the width of the bay window, the frame structure being below significant wave action whereby wave action thereat does not contribute to heave motion of

Abstract: An offshore tension leg platform having a deck, a hull, and a plurality of elongate tendons securing the hull to an ocean floor foundation provides full well workover and production capabilities for autonomous operation and can be installed and operated in any water depth and sustains any environmental loading conditions. The hull supports well risers of well trees located below the water surface at an elevation in close proximity to the connections of the tendons to the hull. Alternatively the risers and trees may be supported above water by a deck or the trees may be located on the seabed. A workover platform supported by a perimeter trackway on the deck may be positioned over any of the well risers for workover operations. Liquid products may be exported from the platform via a pipeline or to a floating tanker. The hull is configured to minimize loadings in the tendons. All components are installed by a drilling vessel without the need for special installation vessels and equipment.

Abstract: An offshore production system of the type that includes a TLP (tension leg platform) (12) and a derrick vessel (14) which moves to the TLP platform (16) whenever the derrick is required. The vessel carries fastener assemblies (131) that rigidly fix the vessel to the platform so they move vertically and horizontally as a single unit, which avoids any need to separately anchor the vessel and which facilitates operation of the derrick in more adverse weather. The vessel preferably has thruster equipment (88) which not only allows it to self-propel itself to the platform, but which also allows the vessel to propel itself and the platform sidewardly, to avoid drift of the platform during drilling. The vessel includes a vessel deck (70) which lies above the platform and a pair of vessel sides (72, 74) with pontoons (76, 78), that lie on opposite sides of the platform.

Abstract: A tower structure for offshore oil and gas fields is formed from various vertically spaced and interconnected tower sections. At least one of the tower sections is rotated about a vertical axis relative to another section so as to define a twisted portion. The number and orientation of the tower sections are varied depending on the particular environment and, particularly the water depth where the tower structure is located.

Abstract: A modular offshore movable drilling platform support includes a double-layer dodecahedrous float having an outer dodecahedrous structure and an inner dodecahedrous structure defining a sealed volume therebetween. The outer dodecahedrous structure is anchored to the ocean floor by tout mooring polyester fiber ropes or aramid guide ropes, and the inner dodecahedrous structure is tied to the ocean floor directly through the use of a riser system. The sealed volume between the inner and outer dodecahedrous structures provides a buoyancy force upon installation of the dodecahedrous float in its position offshore. Both the outer and the inner dodecahedrous structures have 12 pentagonal surfaces formed by the use of rigid Y substructural space components, which contribute to simplified erection process with substantial saving in erection time. The need for expensive underwater welding is minimized in this construction.

Abstract: A connector employs a segmented nut and a seal. The connector includes a housing with a bore having a bowl in it. A shaft extends through the bore, the shaft having exterior threads. Segments are carried on the bowl and move between a upper retracted position to an engaged position. A drive system slides the segments down and rotates them until threads from the segments align with the shaft threads. Each segment has a resilient seal which also has a portion of a thread for sealing against the threads of the shaft. An actuator will move the seals from an outboard position which occurs during rotation to a sealing position after rotation.

Abstract: A tension leg tripod is disclosed for supporting surface facilities on a deck for conducting hydrocarbon recovery operations in deepwater location applications. The tension leg tripod has an elongated, buoyant central vertical column or caisson with three outrigger pontoons. Three tendons are grouped in tendon cluster arrays, each being connected on one end to the outrigger pontoons at a location which is spaced apart from the vertical. The other end of the tendons are anchored to the ocean floor.

Abstract: An apparatus and method for supporting the conductor pipe, the access platforms, the wellhead and the wellhead equipment of an offshore well located in a depth of water above a water bottom after a drilling rig has been removed from the location, where a movable drilling rig is used to drive the conductor pipe into the mudline of the water bottom and temporarily support the conductor pipe while the offshore well is drilled and completed with a wellhead, through the conductor pipe, comprising means for holding the conductor pipe in tension from the drilling rig; a caisson driven into the mudline adjacent to the conductor pipe; a plurality of at least three anchor piles driven into the mudline around the caisson; a plurality of anchor cables; means for attaching to the anchor piles and to the caisson; means for tightening the cables to a desired degree of tension; a plurality of conductor braces mounted to the caisson between the caisson and the conductor pipe for supporting the conductor pipe at intervals alon

Abstract: The floating structure 1 includes a sheet held at a predetermined position by a column 2 which is positioned at the bottom of the water or a cable body 8 in which one end thereof is fixed to the bottom, and a levee wall which is projected from the water surface at a marginal portion. A rigid member can be fixed to the sheet for improving rigidity. Furthermore, a floating body for weakening the wave 70 can be installed at the marginal portion of the floating structure 1.

Abstract: The present invention is a method for reducing the natural period of the second harmonic response in a deepwater compliant tower by decoupling the mass of the production risers from the vertically extending compliant framework.

Abstract: A method of providing a cathodic protection to an installed pile is disclosed in which a plurality of anodes are provided on a tendon foundation guide assembly which is attached to a lowering unit and lowered to the pile. The tendon foundation guide assembly is attached to the installed pile and at least one of the anodes is electrically connected to the pile. The tendon foundation guide assembly is then separated from the lowering unit. In another aspect of the invention, a tendon foundation guide assembly is disclosed for deployment upon the top of an installed pile for cathodically protecting the pile and a tendon receptacle inside the pile.

Abstract: A lean-to well protector apparatus for use on offshore wells having a generally vertical upstanding conductor pipe extending between the sea bed and the water surface includes a pair of jacket legs defining a plane that is angularly oriented with respect to the conductor pipe forming an acute angle therewith. A first plurality of structural chord members interconnects the jacket legs and can occupy the plane defined by the jacket legs. The first plurality of chord members and the jacket legs form a truss that leans towards the conductor pipe during operation of the offshore well. A first clamp connector is positioned at the middle portion of the conductor pipe and a second clamp connector is positioned at the upper portion of the conductor pipe generally near the water surface area. A second plurality of structural chord members interconnects the conductor pipe with the truss at the clamp connectors.