Abstract: A load handling system for offshore load transfer operations, using a floater equipped with a supporting structure for transfer of heavy construction elements between the floater and a transfer site. The supporting structure includes an elongated transfer beam incorporating an arm structure projecting from the floater or a structure attached thereto, and a load carrying point, carried by the arm structure. The load carrying point is displaceable in the longitudinal direction of the arm structure. The arm structure is rotatably supported relative to the floater or a structure attached thereto, in a manner allowing it to be swung in a substantially horizontal plane about a substantially vertical shaft. The arm structure is supported in a manner permitting tilting movements about substantially horizontal axes.

Abstract: Minimized Wave-zone Buoyancy is a new approach to oil and gas platform design with superior construction and performance characteristics compared to state-of-art off-shore drilling and production platforms. Minimized Wave-zone Buoyancy platforms capitalize on low cross sectional area of the portion of the platform exposed to waves. The low cross sectional area reduces buoyancy forces that result from vertical platform movement, enabling the platform to oscillate at a low natural frequency. The low cross sectional area also minimizes the cyclical vertical forces induced by waves. Compare to current designs, application of the Minimized Wave-zone Buoyancy concept will result in a lower natural frequency of oscillation, lower overall weight of platform, or both. Minimized Wave-zone Buoyancy offers an attractive alternative with improved platform stability, fatigue considerations, lower construction and installation costs, and shorter implementation schedule.

Abstract: A floating platform for offshore drilling or production of hydrocarbons comprises a topsides with drilling and/or production equipment (8), and a substructure comprising a lower pontoon (3) and columns (4) connecting the pontoon (3) to the topsides (1). During its operation the platform is exposed to wave forces (9) which cause heave motion (v) and roll and pitch motion (p) of the platform. The substructure has a draught (11) which is at least 40 metres, preferably at least 50 metres and most preferred at least 60 metres, and the ratio between the distance (16) between the columns' centre axes (25), measured along a side of the substructure, and the lower substructure's draught (11) is between 1.0 and 1.5, preferably between 1.2 and 1.4 and most preferred between 1.3 and 1.35.

Abstract: A transporter for removing an offshore platform has an oblong structure with a U-shaped cross section, rotatable by ballasting. The transporter is adapted to remove and carry both a jacket and a topsides simultaneously.

Abstract: A method for fabricating sections of a floating offshore spar type structure and mating the sections offshore. A buoyant hard tank is fabricated vertically. The hard tank is then transported in a vertical orientation to a site where it is mated to a truss section of the spar structure offshore while the hard tank and truss section are both in the vertical orientation. The mated tank and truss sections are then towed in the vertical orientation to the operational site. The hard tank is fabricated with a larger diameter and correspondingly shallower draft than a more traditionally proportioned hard tank.

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: A buoyantly moveable, self-elevating (jack-up) artificial work island or platform self-assembled while floating upon a work body of water by reversibly coupling together a plurality of independently buoyant modular hull components (20, 30), each of which is relatively narrow beam and capable of navigation through relatively narrow waterways. After self-assembly, the work platform is self-elevating upon a plurality of legs (51, 52, 53) to a desired distance above the work body of water. The work platform may be buoyantly moved to subsequent work locations as a unit, or separated into modular hull components each of which may be buoyantly moved separately to the subsequent locations. The work platform may further have a drilling derrick, a hoist, drilling fluid pumps, a rotary table and other equipment associated with earthboring for oil and gas installed thereon. The work platform may be elevated above the water surface a sufficient distance to accomodate operational conditions.

Abstract: Marine structure with one or more suction piles for embedment into the subsea bottom and with buoyancy sufficient such that the structure can be transported over water independently floating, including in an upright position, wherein the buoyancy is concentrated near the suction piles, and may be substantially in line with the suction piles, and wherein the buoyancy is such that if the suction piles touch the subsea bottom with their undersides, at least part of the buoyancy projects above the water surface.

Abstract: A method of constructing SPAR buoys comprising an elongate floating body (1) and a deck structure (2). The elongate body (1) is transported to the mooring site in its horizontal position. During erecting of the floating body (1) by ballasting it with water and alignment with the deck structure (2), the deck structure (2) remains attached to its buoyancy member (7). Hereby the use of large derricks can be avoided which provides a substantial cost reduction. After erecting the floating body, the body (1) may be ballasted to pass below the floating deck structure (2). Alternatively, the deck structure (2) may be deballasted or pulling cables (14) may be used to pull the coupling member (4) of the floating body (1) into contact with the coupling member (12) of the deck construction. Alternatively, the floating body (1) is at its upper ends connected to the deck structure (2) via a pivoting connection (22) such that during coupling the floating body may be hinged against the deck structure (2).

Abstract: A buoyantly moveable, self-elevating (jack-up) artificial work island economically and quickly self-assembled while floating upon work body of water by reversibly coupling together a plurality of independently buoyant modular hull components each of which is of relatively narrow beam and therefore capable of navigation though relatively narrow water-ways. After self-assembly said artificial work island is self-elevating upon a plurality of legs a desired distance above said work body of water. The island may be buoyantly moved to subsequent work locations as a unit or separated into modular hull components each of which may be buoyantly moved separately to the subsequent locations. The island may have a drilling derrick, a hoist, drilling fluid pumps, a rotary table and other equipment associated with earthboring for oil and gas installed thereon.

Abstract: A jack-up, movable drilling platform comprises a telescopic outrigger structure which is movable between a retracted position where it is located above the drilling platform's deck and an extended position where it projects outwards and away from the deck, and a drilling rig which is securely attached to the outrigger structure.

Abstract: A barge (14) that stores liquid hydrocarbon (oil) from a producing facility (12) and offloads it perhaps once a month to a shuttle taker (40), is constructed for unmanned operation except during the once-per-month unloading. The barge has a permanent nonadjustable ballast (53, 54, 55) and has a solar powered system for communication with a central center for normal operation and emergency shutdown. The barge avoids a “hotel system” for a permanent crew (up to 50 people) by avoiding seawater ballast tanks, ballast pumps and related systems. The only person-operated equipment is an engine-generator set (142) and pumps (44), to be operated only during offloading for perhaps 3 days every month. The barge is unpowered except by solar energy or batteries, and is left unmanned except during offloading, so only temporary crew quarters are provided. The barge has a tank assembly (57) with rows of tanks connected in series so oil can be loaded and unloaded from the frontmost tank in each row.

Abstract: An apparatus and method for installing a deck on an offshore substructure is provided. The apparatus comprises a deck supported by lifting mechanisms that are in turn attached to pontoons. The apparatus floats on the water with the lifting mechanisms compressed until transported to an offshore substructure having an upper end located above the water surface. The lifting mechanisms are then extended and the apparatus moved on the surface of the water to position the deck over the substructure. The deck is then lowered onto the substructure and the pontoons are lifted out of the water.

Abstract: An offshore structure which is resistant to wave, earthquake and ice loads and can be quickly installed and abandoned in response to changing environmental conditions includes a caisson having an upper section and a lower foundation section which are separated by a structural diaphragm. When installed, the lower foundation section extends downwardly a distance from the seafloor to provide sufficient lateral and vertical soil resistance to resist lateral and vertical loads on the structure. The upper section is adapted to support a deck structure. The structural diaphragm is adapted to rest on the seafloor when an offshore structure has been fully installed to enhance the lateral and vertical load carrying capacity of the offshore structure. During installation, the structural diaphragm and a pump are used to form suction in the lower foundation section, thus enhancing the penetration of the lower foundation section into the seafloor.

Abstract: A method for disposing of an offshore platform jacket comprises suspending the jacket in one piece under a tow vessel, towing it to the disposal site and safely and quickly releasing the jacket at the disposal site. Once the jacket foundation piles have been severed, the first end of the jacket is lifted using a derrick barge crane or winch connected to a first lift rigging device until the first lift rigging device engages with a first release device. The second end is lifted in a similar manner with a second lift rigging device and a second release device until the jacket is suspended substantially beneath the tow vessel. The lift rigging device include a spreader bar having at least one skid shoe attached thereto, at least two padeyes attached at opposite ends of the spreader bar, a lift sling attached to the padeyes and at least two jacket support slings. Each release device is attached to the tow vessel and includes at least one rocker beam having a connector.

Abstract: A novel automatically submersible and refloatable underwater tubular pipe platform geometric structure adapted for deployment in underwater target monitoring systems and the like, wherein the floating upon the surface of the water enables flooding of the pipe structure and its submergence, and the introduction of compressed air drives the water out of the pipe platform structure to enable its automatic re-floating.

Abstract: This invention provides a method for constructing an offshore platform by mating a self-floating deck structure with a self-floating substructure. The self-floating deck structure may be a floating pier or barge, on which the desired equipment has been mounted. Mating is achieved by at least partially submerging the substructure, positioning the pier or barge above it, and deballasting the substructure to create a vertical bearing force between the substructure and the pier or barge. Horizontal force may be transmitted between the deck and substructure by a variety of mechanical, structural, and magnetic means.

Abstract: A method is disclosed for disposing of an offshore platform jacket by suspending the jacket in one piece under a tow vessel, towing it to the disposal site and safely and quickly releasing the jacket at the disposal site. Once the jacket foundation piles have been severed, the first end of the jacket is lifted using a derrick barge crane or winch connected to a first lift rigging means until the first lift rigging means engages with a first release means. The second end is lifted in a similar manner with a second lift rigging means and a second release means until the jacket is suspended substantially beneath the tow vessel. The lift rigging means include a spreader bar having at least one skid shoe attached thereto, at least two padeyes attached at opposite ends of the spreader bar, a lift sling attached to the padeyes and at least two jacket support slings. Each release means is attached to the tow vessel and includes at least one rocker beam having a connector.

Abstract: Method for carrying out operations under water by means of a crane (3) equipped with a tool which is erected on a pontoon (1) which has been fixed and which can be jacked up, wherein an underwater working room (4) which is mainly open at the bottom is let down on the place of work, in that the water is pushed out of this working room (4) by means of compressed air, in that the place of work is divided in compartments in the working room (4) itself, i.e. out of the water, and in that one or several positions of the compartment division in which the crane (3) will have to carry out an operation are transmitted to the crane (3), after which the underwater working room (4) is lifted and the crane carries (3) out the operation.

Abstract: Apparatus for transporting and installing a deck of an offshore oil production comprises a floating barge (10) adapted to support the deck (1) and provided with devices for moving the deck (1). The apparatus includes a support framework (11) for the deck (1) adapted to be placed on the barge (10) and including the devices for moving the deck (1) in the form of at least one rack (21) that can be moved vertically by drive mechanisms (20).

Abstract: The invention relates to a method for removing or positioning a structure (103) or a part (107) of a structure which is erected on an underwater bed or anchored to the underwater bed. When the structure (103) is being removed, it is detached from the underwater bed. Then, the structure (103) is connected to a hoisting mechanism which is arranged on a separate hoisting vessel (100). The structure is hoisted up by the hoisting mechanism and is attached to a transport vessel (1) in such a manner that it can tilt about a horizontal axis. Then, the structure is tilted into a substantially horizontal position. The structure is positioned in the reverse order.

Abstract: Apparatus for providing an offshore drilling operation in a sea, the apparatus comprising a drilling derrick support structure (2) having a base (4) to rest on the sea-floor (5) and a deck (7) to support a drilling derrick (1), the structure being in the form of a concrete block (2) having a hollow cavity to enable the block (2) to be floated to the site where drilling is to take place and being adapted to receive ballast into the cavity in such a way and in a sufficient quantity as to cause the block (2) to sink base-first and rest upon the sea-bed with the deck (7) clear of the surface of the sea, a drilling derrick (1) for mounting on the deck (7) of the block (2) and a tender assist barge (3) for transport to the site in down to 2 m of water to provide services, supplies and equipment to the drilling derrick (1).

Abstract: A transporter for use in a method for removing a jacket for an offshore platform includes an oblong structure rotatable by ballasting, with a sliding saddle which is movable in the longitudinal direction of the oblong structure and adapted for securing the jacket, thus enabling the jacket to be moved in relation to the transporter by the sliding saddle after being attached to the sliding saddle and released from the seabed.

Abstract: A buoyancy device is described comprising a number of buoyancy members (9, 9A, 9B) which are substantially equi-spaced around the circumference of a coupling member (7) and the buoyancy members (9, 9A, 9B) being coupled to the coupling member (7) At least two of the buoyancy members (9, 9A, 9B) are inflatable members (9, 9A, 9B). The inflatable members (9, 9A, 9B) are formed from a substantially flexible material such that an inflatable member (9, 9A, 9B) substantially collapses when deflated. The coupling member (7) is is typically coupled to a structure, which may be a drilling rig (3) which requires to be lifted and subsequently moved, or which may be a large device such as a well head Christmas tree for an oil well which requires to be deployed in deep water.

Abstract: A method and apparatus that eliminates the need for a derrick barge to lift the deck into place on a floating offshore structure. A connector is used to connect the transport barge to the floating offshore structure. The connector is a type that allows only relative pitch motions between the transport barge and floating offshore structure in response to sea states acting on the barge and floating offshore structure. The connector is also a type that allows disconnection while large forces are acting on the connector. One or more skidding girders attached to the legs of the deck support the legs of the deck above the skidding surface of the transport barge. A skidding surface on the girders, and complementary skidding surface on the surface of the transport barge and floating offshore structure, allow the deck to be skidded from the barge to the floating offshore structure.

Abstract: A drilling vessel is provided for selectively drilling two or more wells from a single location of the vessel, comprising a buoyant hull having a deck, including ballasting devices in the hull for allowing the vessel to be stabilized on the bottom surface of a body of water; a movable substructure in contact with the deck, wherein the movable substructure includes a drilling platform having a plurality of downwardly extending support legs attached thereto, wherein the height of the drilling platform from the deck is sufficient to allow simultaneous drilling and production activities to occur; and a repositioning system, operatively connected between the support members and the deck, for moving the drilling platform in a predetermined direction relative to the deck. In a preferred embodiment, a plurality of lift and roll jacks are employed beneath each level of a two-tiered repositioning system such that the substructure may be moved in both a transverse and a longitudinal direction.

Abstract: A jack up work platform is recited. The work platform comprises a hovercraft vessel outfitted with several jack up legs. The hovercraft can traverse environmentally sensitive terrain such a brackish and freshwater marshes without the need to dig canals that may cause or exacerbate salt water intrusion. Once the drilling or exploration site is reached, the jack up legs may be lowered, lifting the work platform above the surface. Once the vessel is secured on the legs, it may be used like a conventional oil field work platform for drilling, exploration, or construction jobs for which other work platforms or vessels are typically used. The deck of the hovercraft may serve as the work platform or the deck may be provided with a cantilevered work platform extension. The hovercraft will preferably be provided with typical oil field heavy machinery such as a crane for assembly of the legs, and drill stem as well as for work on other structures.

Abstract: A jack-up platform of the type having a buoyant upper barge (10) mounted so that it can be moved along the length of bearing legs (12), mechanical mechanism (18) for moving the legs (12) relative to the barge (10), and submerged storage tank (14) intended to rest on the bottom. The tank (14) has a lower opening (26) allowing the inside of the tank (14) to be placed in contact with the marine environment. The tank defines a bell-shaped/inverted U-shaped cavity confining an air bubble (30) in its upper part. The tank (14) is connected to the lower end of the legs (12) so that it can be moved relative to the barge (10) from the mechanical mechanism (18) for moving the legs.

Abstract: A drilling rig, in particular for the offshore industry, in the form of a jack-up platform on which a cantilever is mounted so as to be movable at least substantially horizontally and in a first direction, with the cantilever projecting more or less outside the jack-up platform. On the cantilever a drilling platform is present, which drilling platform is movable relative to the jack-up platform in a second direction, different herefrom. This drilling platform is fixedly mounted on the cantilever while the latter is movable relative to the jack-up platform in both abovesaid directions.

Abstract: A mobile offshore drilling unit includes a hull member having an opening of predetermined size for receiving a separately fabricated, interchangeable, rig block, which further includes a draw works, a drilling floor, a diesel driver, an electric generator, a derrick, and at least one each of a mud pump, mud tank, a fuel tank, and a drilling water tank. The method of constructing such a unit includes constructing the hull member at a marine shipyard and fabricating the interchangeable rig block at a remote location. The rig block is constructed with the main deck having a drilling floor and mounting a draw works thereon; constructing a machinery deck with a diesel driver, an electric generator, and at least one mud pump; and constructing a tank deck with at least one each of a fuel tank and a water tank.

Abstract: An offshore system is provided of the type that includes riser pipes (30) extending up from the seafloor (44) to a tall and narrow caisson (12) at the sea surface, with the caisson moored by mooring lines (34) extending to the seafloor and anchored thereat, which minimizes bending of the upper portion of the riser pipes when the caisson drifts in severe weather. Although the caisson has a Ballasted lower end and buoyant upper end to keep its axis (20) vertical, a device is provided for applying a horizontal force (54) to a location along the caisson that is vertically spaced from the upper ends of the mooring lines, to tilt the caisson so the axis of the caisson is parallel to portions (82) of the riser pipes lying immediately below the caisson. In one arrangement, a second set of mooring lines (60) is provided, that have upper ends coupled to second locations (64) along the caisson that are vertically spaced from the upper ends of the first mooring lines.

Abstract: A submergible vessel for use in shallow-water oil drilling includes a pair of spaced pontoons selectively submergible and raisable in water by the admission and expulsion of water, a main deck, a frame supporting the main deck over the pontoons, and a jacking system for horizontally and vertically translating a packaged drilling rig positioned thereon. The jacking system includes a pair of parallel cantilever beams positioned on the main deck adjacent the stern, vertical jacks for selectively translating the cantilever beams in a vertical direction above the main deck, and horizontal jacks for selectively translating the cantilever beams in a horizontal direction along their longitudinal axes. The deck has an inwardly extending slot formed therein at the stem, and the cantilever beams are positioned on either side of the slot, with their longitudinal axes parallel to the longitudinal axis of the deck.

Abstract: An elevating unit for a jack-up rig provides a pinion gear that rotates upon a support frame for engaging a toothed rack of each leg of the jack-up rig. Each pinion gear is mounted on a gear shaft that extends in opposite directions from a plane of rotation of the gear. First and second roller bearings are mounted upon the frame for supporting the pinion gear at first and second pinion gear shaft end portions. On one shaft end portion, a planetary gear box engages the shaft, the gear box being motor driven. On the opposite side of the shaft end portion a brake hub is attached to the pinion gear shaft and carries a brake drum. A brake band extends about the drum, the band being operable to frictionally engage the brake drum to retard movement of the drum, hub and pinion gear shaft relative to the frame.

Abstract: A soft landing structure to be installed on the water bottom ground with decreased cost and construction time. The soft landing structure includes a ballast tank for storing a desired amount of water, a lower structure connected to a top of the ballast tank under the surface of the sea water, and an upper structure mounted on the lower structure at least a part of the upper structure is positioned above the surface of the sea water. The soft landing structure is placed on the water bottom ground which has been improved to increase strength of the ground against overall weight of the soft landing structure.

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: A construction jack-up barge comprising a barge (11) supporting a tower (13) in a stowed horizontal position for transport and a vertical position for deployment. The tower (13) has three fold-out legs (15), each equipped with a footing assembly (17). The tower (13) is supported for rotation between a horizontal stowed position and a vertical position for deployment, about the barge (11), by a pivotal connection (19). The tower is also supported in a traveling frame (20) which has concave shaped rollers (21) which track each chord of the tower (13), allowing the tower (13) to be moved up and down relative to the barge (11), when the tower is being deployed. In the vertical position the tower (13) is received through an opening which extends through the deck to the hull of the barge (11). A central cut out portion (33) extends from the stern of the barge (11), to the opening, to provide a pathway for the tower (13) as it rotates between the horizontal and vertical positions.

Abstract: An elevating unit for a jack-up rig provides a pinion gear that rotates upon a support frame for engaging a toothed rack of each leg of the jack-up rig. Each pinion gear is mounted on a gear shaft that extends in opposite directions from a plane of rotation of the gear. First and second roller bearings are mounted upon the frame for supporting the pinion gear at first and second pinion gear shaft end portions. On one shaft end portion, a planetary gear box engages the shaft, the gear box being motor driven. On the opposite side of the shaft end portion a brake hub is attached to the pinion gear shaft and carries a brake drum. A brake band extends about the drum, the band being operable to frictionally engage the brake drum to retard movement of the drum, hub and pinion gear shaft relative to the frame.

Abstract: An apparatus and method for pressurizing the inside of tubular members of an offshore structure that are immersed in sea water so that the internal pressure resists the hydrostatic pressure of the sea water. To achieve this internal pressure, gas is generated automatically on the inside of the members as the structure descends to its in-place location. The gas can also be used to deballast a tubular member.

Abstract: An offshore structure is disclosed for placement on a sea floor foundation located in a body of water containing moving ice masses and water waves. The offshore structure has a foundation base which contacts the sea floor foundation and at least three stepped stages which are stacked above the foundation base. Each stage has an outer hull to engage moving ice masses and water waves. Additionally, each stage has an outer horizontal diameter which is smaller than the outer horizontal diameter of the stage immediately below it.

Abstract: An offshore platform structure is disclosed for temporarily using a jack-up rig for well operations in deepwater applications having a bottom founded jacket base which supports a surface tower which extends above the ocean surface and a subsea rig support interface which is adapted to support the jack-up rig for well operations. At least one selectively buoyant rig support buoyancy tank connected to the rig support interface whereby a portion of the temporary load on the jacket base in supporting the jack-up rig for drilling operations may be alleviated.

Abstract: An offshore platform structure is disclosed for temporarily using a jack-up rig for well operations in deepwater applications in which a jacket base supports a surface tower and a subsea rig support interface adapted to accept the jack-up rig for well operations. The bottom founded jacket base is designed for dynamic response with the mass of the jack-up engaged and at least one ballastable rig support buoyancy tank connected to the rig support interface whereby the weight of the jack-up rig is substantially offset by buoyant forces supplied by the rig support buoyancy tank when the jack-up rig is deployed on the jacket base and the mass of the jack-up rig is substantially replaced in the offshore platform structure by ballast in the rig support buoyancy tank when the jack-up rig is removed.

Abstract: An improved subsea template system. A drilling template is adapted to rest on the seafloor. The drilling template includes at least one conductor guide through which a well is drilled. An alignment structure is attached to the top of the conductor guide and fits within a conductor guide of a production template. The production template includes at least one conductor guide more than the drilling template. Once engaged, the alignment sleeve serves to coaxially align the conductor guide of the drilling template with a corresponding conductor guide of the production template.

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: 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 marine riser section which has an elongated light-weight composite shells is provided with a protective liner of elastomer, epoxy resin or metal. The choice of elastomers includes nitrile rubber, fluorinated rubber or chlorosulfonated polyethylene; the choice of resins includes an aromatic amine cured epoxy with an added styrene curing system; and the metals include steel or titanium alloys or electroless nickel coating.

Abstract: An offshore platform structure is disclosed for facilitating use of a jack-up rig for well operations in deepwater applications while reducing the jacket size and increasing the flexibility of field development. The structure has a bottom founded jacket base and a surface tower supported by the jacket base and extending above the ocean surface. A platform deck is supported by the surface tower and a subsea rig support interface is presented at the top of the jacket base which is adapted to receive the jack-up rig for well operations. Another aspect of the present invention is an offshore platform system which includes a jack-up rig having a plurality of legs extending from a combination hull/deck structure and engaging the rig support interface. Well operations equipment provided by the jack-up rig which includes a cantilever deck extending from the combination hull and deck structure to present a derrick in substantial vertical alignment with the surface tower.

Abstract: The present invention is a reusable jacket base for an offshore platform having a plurality of jacket legs with an interconnecting framework. Pile sleeves are connected to the jacket legs which have a vertically extended, open-ended cylindrical member having a second stage sleeve which is connected to the jacket leg and a first stage sleeve projecting coaxially from the second stage sleeve. First and second stage locking profiles are presented inside the first and second stage sleeves, respectively. The first stage sleeve is thus accessible for cutting operations, severing both the first stage sleeve with the first pile-to-pile sleeve connection inside and the connected pile section within. This allows retrieval of the platform jacket, but preserves a second stage pile sleeve for re-deployment. Another aspect of the present invention is an improved pile sleeve adapted to facilitate reuse.

Abstract: A method and apparatus for transporting and using a drilling apparatus or a construction crane apparatus from a single moveable vessel is provided. Either a drilling apparatus or a construction crane apparatus is skidded onto the deck of a jack-up rig which is then floated to a remote location for use of the apparatus. The skidding of the construction crane apparatus is facilitated by a new and unique pony structure to raise the base of the construction crane apparatus above a skid on the jack-up rig.

Abstract: A riser tensioner system 10 is provided for use on offshore oil drilling platforms to support a riser 12 relative to a floating platform. The riser tensioner system 10 uses either elastomeric pads 32 or helical metal springs 100 as an energy absorbing medium, rather than hydraulic, or pneumatic systems. The elastomeric pads 32 or helical metal springs 100 are maintained in compression within a shock absorber housing 76 by a plunger 70 which is compressed by the weight of the riser 12. If the riser tensioner system 10 is arranged to place the shock absorber 20 in tension, the shock absorber plunger 70 is inverted in the housing 76 to maintain the elastomeric pads 32 or helical metal springs 100 in compression. To achieve varied response characteristics, nested inner and outer elastomeric pads 50, 52 or compression springs 102, 106 are arranged to act together.

Abstract: A method and system are disclosed for establishing hydrocarbon production for offshore reservoirs in which a compliant platform is installed at a selected site, an offshore drilling vessel is docked to the compliant platform and the vessel is positioned over a selected well site for conducting drilling operations, and the production riser is transferred from the vessel to the compliant platform and secured there. Communication between a surface tree installed on the production riser and facilities supported by the compliant platform is established and these steps are repeated for each selected well site served by the compliant platform.