Abstract: An output gear is on an elongate sheath capable of withstanding torsion between its ends. The sheath is equipped with a device for measuring the torque borne by the gear. The device for measuring the torque comprises a bar which extends through the sheath, fixed to the sheath at one end and equipped at the other end with a lever in contact with at least one linear displacement sensor, preferably of the inductive coupling type. The sensor can supply data to a central unit for collecting all data gathered from each output gear. The central unit comprises a computer for determining a mean torque value, and optionally, the weight of the platform to be established, and a controller for automatically controlling the plurality of maneuvering mechanisms.

Abstract: Carbon dioxide gas collected from combustion exhaust gas or the like is transported in a liquefied gas state on the sea by means of ships up to a marine float installation provided with a throw-in pipe reaching to the deep sea, and then the liquefied carbon dioxide is thrown into the deep sea through the throw-in pipe.

Abstract: The jackable oil rig employs a leg formed of a plurality of corner columns and transverse stays. Each column is formed of an outer pipe, and inner pipe which defines an annular space with the outer pipe and a hardenable material such as concrete in the space between the pipes. The outer pipe has a constant outer diameter along the length while the inner pipe has a constant outer diameter along the length and an increasing wall thickness from a top section to a bottom section. The wall thickness of the inner pipe may increase step by step from about 30 millimeters in the upper section to about 150 millimeters in the lower section. The construction of the corner column allows oil rigs to operate at ocean depths down to 200 meters.

Abstract: A mobile cofferdam for use in the construction of elongated structures win a body of water is characterized by a water-tight rectangular shell which is guided and supported off the previously constructed segment of the sill or wall structure being built. The mobile cofferdam shell is floated into place, sunk, dewatered, and used as a cofferdam during construction of the sill. The mobile cofferdam is guided and supported off the previous placed concrete sill or wall and proceeds in a horizontal slip-form fashion. The walls of the mobile cofferdam are designed as spaced truss structures with skin plate on the inner, outer, top and bottom surface thereof to define a chamber which can be filled or evacuated with water to float the shell structure. The trailing end of the shell conforms to the sill or wall under construction and includes seals along the contact area for mating with the previously constructed sill portion.

Abstract: A semi-submersible production platform (10) intended for oil production, water injection and oil and gas export includes a hull (11) of basic rectilinear shape consisting of floats (17) with rectangular cross-section forming a closed square ring (12). Four columns (13) of square section are located, one in each vertex, of the closed square ring (12). A risers receipt system (14) consists of lateral supports (15) and connectors of square section (16). A passive anchoring system (19) is provided along with a truss-shaped deck structure (23), an equipment arrangement (24) with full seggregation of process equipment, utilities and quarters. A water intake (25) system at large depths has an intake pipe (26) connected at the top to the float (17) through a flexible coupling (27).

Abstract: A method and apparatus for installation of heavy, ballastable, gravity fundament structures on the sea bottom at large depths. In accordance with the invention, there is utilized air, water, and a liquid lighter than water in various proportions and combinations to provide the structure with the required buoyancy and submerged weight during the sequential phases of the transport and descent operations in order to finally position the structure in a selected location on the sea bottom. Various modes can be used to accomplish the descent and the structure may in a final stage be penetrated down into the sea bottom to a sufficient degree.

Abstract: An offshore deck or platform unit is provided with depending legs having shock absorbing stabbing tip assemblies for engagement with the upstanding columns of a marine substructure to transfer the weight of the deck to the substructure by positioning the deck relative to the substructure with a barge and ballasting down the barge to move the deck into engagement with the substructure. The barge also carries a deck support structure comprising plural sand jack assemblies which provide for disengagement of the barge from the deck. The stabbing tip assemblies include coaxially arranged primary locating pins which are dropped into position to hold the location of the deck relative to the columns and annular resilient collars for transferring vertical and lateral shock loads between the columns and the deck during the transfer process.

Abstract: The immersion and positioning of a sink element on the sea bottom is controlled by providing a weight system suspended from the sink element. An auxiliary surface vessel has a control cable directly connecting the vessel with the weights system suspended from the sink element. The sink element is immersed with the weight system suspended therefrom and therebelow until the weight system contacts the sea bottom and the sink element reaches a preselected stabilized equilibrium elevational position above the sea bottom. Then the sink element can be laterally displaced while substantially maintaining the height of the sink element above the sea bottom by having the auxiliary surface vessel pull on the control cable connected to the weight system in a direction of movement towards the final location site. The weight system contacts the sea bottom during this movement to help control the movement of the sink element and minimize the influence of outside forces.

Abstract: A method is disclosed for conducting offshore well operations from an auxiliary vessel in support of a compliant platform. The auxiliary offshore drilling vessel is restrained with respect to the compliant platform in position adjacent the well bay of the compliant platform and vertically aligned with a selected well site for conducting well operations.

Abstract: A marine structure has a surface corrosion resistant covering material of titanium-clad steel plates that are continuously arranged in vertical and horizontal directions. Long sides of the titanium-clad steel plates at the top and bottom steps of the corrosion resistant covering material are horizontally arranged to minimize the number of joints between adjacent titanium-clad steel plates, and a space exposed at an end of each joint at the top and bottom steps of the corrosion resistant covering material is closed with a sealing cover.

Abstract: A tension leg well jacket ("TLWJ") is disclosed which is configured to receive well operations support from an offshore drilling vessel docked thereto and to receive the production riser in transfer operations from the vessel to the TLWJ. This permits a minimal platform suitable for supporting production risers which is particularly useful in deep water applications.

Abstract: A mat jack-up drilling platform converted to a floating drilling platform. The mat jack-up platform, which normally contains a platform, a mat for resting on the seafloor, and legs attached at one end to the mat and on which the platform can be raised and lowered, is converted to a floating rig by jacking the mat to the platform, permanently joining the mat to the platform, and removing the legs.

Abstract: The structure comprises a concrete monolithic caisson (3) consisting of a top slab (5) and a bottom slab (5') resting on a seabed. Two concentric peripheral walls (6, 7), an inner and an outer respectively, are designed to withstand the impacts of icebergs. These two walls (6, 7) extend substantially vertically between the slabs (5, 5') and are rigidly connected with them. Vertical partitions are arranged between the two walls so as to connect them in a lattice structure. Vertical defensive elements (8, 9) are disposed over at least a part of the outer periphery of the caisson. The defensive elements (8, 9) are integral with the outer wall of the caisson (3). These caissons are intended for a platform structure located in Arctic regions for production in a hydrocarbon field.

Abstract: A system for aligning a drilling module on a jack-up rig with a drilling module support surface on a fixed rig wherein the angular disposition of the drilling module is varied by moving a portion of the jack-up rig on at least one of the legs of the jack-up rig to bring the angular disposition of the drilling module into alignment with the angular disposition of the drilling module support surface on the fixed rig prior to transferring the drilling module from the jack-up rig to the fixed rig. The system also includes a position assembly for positioning the drilling module on the drilling module support surface in a predetermined aligned position.

Abstract: An improvement in efficiency of marine type oil spill clean up is achieved by using slideable fastners and support legs extending from a floatable unit to hold a skimmer unit in a relatively fixed horizontal position while using retractable cables with a hydraulic tensioning means to maintain the skimmer in a nearly constant relationship to the wave surfaces.

Abstract: A device for the integrated suspension and manipulation of legs supporting a jack-up oil platform having a hull mounted displaceably on the legs by drive mechanisms having at least two opposite units each formed by a motor associated with at least one speed reducer driving an output gear co-operating with opposite racks mounted on at least part of the length of the legs. The opposite units of each drive mechanism are mounted in articulated fashion on a structure supporting them via at least one bearing allowing a determined angular deflection of the units and of each corresponding output gear. The motor and the speed reducer of each opposite unit are housed in a member for absorbing energy, used, in particular, at the moment of the placement of the legs on the sea bed and for limiting the stresses due to the flexure of the legs under the action of swells and the wind.

Abstract: A method of constructing a column-like marine structure including the steps of constructing and placing an assembly of floats in a dry area, placing on the float assembly a column base having its own buoyancy, flooding the area to float the assembly of floats and column and moving them to deeper water, ballasting the floats to sink them and while maintaining buoyancy of the column removing the floats, completely ballasting the column to sink it, reconnecting the floats around the top of the column, constructing a further column part on top of the column, lifting the assembly by the buoyancy of the floats and/or the buoyancy of the column and floating it to a desired location in deeper water.

Abstract: Improved methods and apparatus are provided for landing and securing a payload to a subsea assembly, such as a hydrocarbon recovery assembly, utilizing a surface vessel and a subsea ROV. The payload is suspended from a submersible payload package, and the package and payload are lowered subsea by a vessel cable. Guide cables extending from the package may be secured to the subsea assembly, and a floatation device thereafter activated to render the package positively buoyant, thereby making the guide cables taunt and relaxing the vessel cable to de-couple the package and payload from the surface vessel. The guide cables are then used to lower the payload from the package onto the assembly, and the payload secured to the assembly with the ROV. The floatation device is subsequently deactivated such that the pacakage is no longer positively buoyant, thereby re-coupling the package to the surface vessel.

Abstract: A man-made sea defense system is constructed using floatable sea-defense caissons which are floated in the ocean to a pre-selected ocean site and then sunk to the ocean floor and connected in end-to-end relation to form a line of sea-defense caissons whose bottoms are secured in place on the ocean floor and whose tops extend above the ocean surface. The opposite ends of the line of sea-defense caissons are anchored by anchor tower caissons which extend higher above the ocean surface than the sea-defense caissons. A plurality of storage caissons are secured in place to the ocean floor on the leeward side of the line of sea-defense caissons for storing bulk materials. The storage caissons may be connected to the line of sea-defense caissons in a closed loop configuration to define a sheltered area on the leeward side of the sea-defense caissons. The sheltered area may remain filled with seawater to form a wet polder or may be pumped dry and filled with dry material to form a dry polder.

Abstract: A tether system for a semisubmersible work platform which may be based on deep water, comprising a number of pontoon elements mounted in a frame configuration, upright columns and a work deck for exploitation of oil or gas fields below the sea bottom. The system comprises a sea bed anchor template, which is provided with receptacle means for tendons, running up to connectors at the work platform. The receptacle means in the sea bed anchor template are located along a circular track on which a carrier can move. The carrier has sheave means for one or more handling line for a tendon which is provided with a running collar. The connectors for the upper ends of said tendons are located at the outside of the columns.

Abstract: A system for aligning a drilling module on a jack-up rig with a drilling module support surface on a fixed rig wherein the angular disposition of the drilling module is varied by moving a portion of the jack-up rig on at least one of the legs of the jack-up rig to bring the angular disposition of the drilling module into alignment with the angular disposition of the drilling module support surface on the fixed rig prior to transferring the drilling module from the jack-up rig to the fixed rig. The system also includes a position assembly for positioning the drilling module on the drilling module support surface in a predetermined aligned position.

Abstract: This invention pertains to a braced offshore structure that is constructed on land as a single unit in a compact bundle before being transported on a barge to the installation site. After the compact unit is launched, it is unfolded and ballasted before being installed upon the ocean floor. This structure consists of an elongated central tower having a plurality of braces pivotally secured thereto. These braces are initially positioned generally parallel to this central tower within recesses in the central tower but after the braces are unfolded, they extend at an angle to the central tower.

Abstract: A riser system includes inflatable buoyancy bladders and a near surface disconnect so that a drilling vessel can rapidly disconnect from the riser leaving the riser in a freestanding buoyant position.

Abstract: A mooring system comprising a multiple degree of freedom coupler interconnecting a floatation section and an anchoring section of a dock system. The system also comprises a drawbridge section, a gangway section and a shoreline mooring section. The multiple degree of freedom coupler prevents hanging-up of the floatation sections which is an expensive, frequently occurring problem experienced by virtually every free floating anchor/sleeve dock system currently in existence.

Abstract: An improved apparatus is disclosed for setting a deck structure or other marine superstructure using a barge mounted cantilevered support structure. The cantilevered support structure is attached at one end of a floating vessel. The cantilevered support structure extends past the edge of the vessel and, in one embodiment, includes means for rotating parallel support members about the deck of the floating vessel permitting the cantilevered support structure to be raised and lowered while it remains substantially parallel with the top of the offshore platform enabling the superstructure to engage the top of a previously installed offshore platform in a synchronized manner. Alternatively, this superstructure may be aligned directly over the platform. A cantilevered drilling rig is then aligned over the cantilevered support structure and used to lift the deck structure or marine superstructure, permitting the vessel and cantilevered support structure to move.

Abstract: Methods and apparatus for supporting vertical members in an offshore environment, utilize pivoting support members whcih are secured to the vertical member.

Abstract: Weights in the form of water-filled flexible tubes are attached onto the pressure supported roof membrane of a building. The weights contour the membrane from a single dome into smaller elongated domes. The decreased radii of curvature of the smaller domes substantially reduce both the stress within the membrane and tension exerted by the membrane on the building walls.

Abstract: A mooring system comprising a multiple degree of freedom coupler interconnecting a floatation section and an anchoring section of a dock system. The system also comprises a drawbridge section, a gangway section and a shoreline mooring section. The multiple degree of freedom coupler prevents hanging-up of the floatation sections which is an expensive, frequently occurring problem experienced by virtually every free floating anchor/sleeve dock system currently in existence.

Abstract: A buoyant vessel which alone can support a heavy superstructure has a well within which a floating body is disposed. The floating body can displace sufficient water in the well to support the superstructure by itself. Valves are provided for transferring water into and out of the body to lower and raise the superstructure with respect to the water surface on which the vessel is floating.

Abstract: The present invention is of a deepwater platform which incorporates a central two-piece tower extending from the ocean floor to at least a few feet above the ocean surface. The central tower is divided into an upper tower section and a lower tower section, with the lower tower section being substantially higher than the upper tower section. The tops of outwardly and downwardly positioned struts are connected to the tower at the dividing point between the upper and lower tower sections. Both the lower end of the central tower and the lower ends of the struts are anchored to the ocean floor by driving piles through pile sleeves secured thereto. The dividing line between the upper tower section and the lower tower section depends upon the angle at which the struts are positioned against the tower.

Abstract: A marine structure, for example an offshore production plantform comprises a floating base section, which can be flooded, having caissons thereon and a topsides mounted on the caissons. The caissons comprise at least two telescopic sections,the uppermost section carrying the topsides and the lowermost being mounted on the base. The structure can be installed by supporting hte topsides for example, using the derrick of a jack-up rig, and then partially flooding the base section until the jack-up rig is supporting the topsides. On lowering the hook, more of the topsides weight is applied to the base and the structure sinks to the sea-bed where it is secured by grouting. The upper supported section is then lifted to the desired height and the telescopic sections locked. Piling and drill casings, strings etc. may be lowered through the topsides into the hollow regions within the legs.

Abstract: In an anchoring arrangement for releasable anchoring of the legs of a marine tension leg platform in a foundation on the sea floor, the lower ends of the tension legs with an end head (1) are lowered into a cylindrical anchoring casing (4). For anchoring the leg in the foundation, locking elements (7) are provided at the tension leg insertion end of casing (4), on the inside of the cylindrical casing wall, for cooperation with bosses (2) on tension leg head (1). Anchoring casing (4) is, furthermore, on the outside of its cylindrical wall, at the insertion end, provided with further bosses/grooves (10). The latter are intended for cooperation with bosses (14,15) and grooves which are provided on the inside of a cylindrical steel ring (13), which is intended to be integrallly moulded into the foundation on the sea floor. Over the end edges of casing (4) and the cylindrical integral ring (13) a locking ring (16) is provided on a contact face to provide additional fixation of the anchoring.

Abstract: Protective barrier consisting of at least two ballastable elements (3, 4) adapted to surround at least partially the work to be protected (1).The height of the individual elements is greater than the water depth. The elements comprise a connection device permitting the structural continuity of the elements after assembly. The protective barrier is entirely independent of the work to be protected. The positioning of the elements around the work is effected by means of a positioning system provided in the sea bed and/or the individual elements of the protective barrier.

Abstract: An independent modular structure for providing lateral support for the well conductors of an offshore well platform and a method for designing and using such structure are disclosed. The modular structure can be inserted into a void in the jacket of the well platform. The vertical spacing between adjacent support points on the modular structure is determined by the lateral support requirements of the well conductors. Accordingly, the design of the platform jacket may be optimized without consideration of the lateral support requirements of the well conductors.

Abstract: In a flexible tension leg member an adjustable spacer is provided between the coaxial tension leg members joined in the member.

Abstract: A jack-up rig includes a cantilever beam assembly and a drilling module is mounted on the cantilever beam assembly. The jack-up rig also includes means for moving the cantilever beam assembly from the storage position to extended positions wherein a rearward end of the cantilever beam assembly is extended from the jack-up rig. The fixed platform comprises a fixed platform support structure having a drilling module support surface and a beam opening. The jack-up rig is positioned near the fixed platform with the cantilever beam assembly generally aligned with the beam opening in the fixed platform support structure. The cantilever beam assembly then is extended through a portion of the beam opening to an extended position wherein the drilling module is supported on the cantilever beam assembly a distance generally above the drilling module support surface. The jack-up rig then is lowered to a position wherein the drilling module is supported on the fixed platform support structure.

Abstract: A system and method for mating a preconstructed integrated deck mounted on a barge with a previously installed offshore jacket is provided. The system comprises at least two primary load transfer units, at least one secondary load transfer unit, and a plurality of drop block assemblies. The primary load transfer units are designed to absorb a portion of the weight of the integrated deck as the integrated deck is lowered onto the jacket. The secondary load transfer units are designed to engage after a portion of the weight of the integrated deck has been absorbed by the primary load transfer units and to assist the primary load transfer units in absorbing an additional portion of the weight of the integrated deck as it continues to be lowered onto the jacket. The drop block assemblies are designed to disengage the integrated deck from the barge and thereby transfer the remaining weight of the integrated deck to the jacket.

Abstract: An artificial island structure which is constructed on land can be conveyed to and placed in a vertical standing position on an underwater base site by loading the island structure, while horizontal, on a floating buoyant carrier, transporting the carrier with island structure thereon to a large displacement buoyant vessel, journalling one end of the carrier to the vessel, transporting the vessel with carrier and island structure to a position over the underwater base site, ballasting the carrier until it swings to an upright position, suspending the upright island structure from the vessel, disconnecting the carrier from the island structure, and lowering the island structure onto the underwater base site.

Abstract: This invention is a method and casing (1) for constructing a rigid structure upon the bottom of the water. The casing to be used is a lost pillar casing of particular shape. It is larger at the bottom than at a higher level and preferably is composed of flat plates formed into a polygonal cross sectional shape with similarity to a multiple sided pyramid. It can be combined with wall casings slit into recesses of the pillar casings. The wall casings can be double wall casings in which case concrete is filled therein and bulk stoney material is filled into the interior of the pillar casings or between the casings.

Abstract: An offshore well test platform system is positionable above one or more underwater wells and comprises a submerged buoy restrained below the surface of the water by a plurality of laterally extending, tensioned cables, a platform structure removably connected to a submerged buoy with an upper portion that extends above the surface of the water, and a flexible riser that connects the well to a well test platform deck above the surface of the water.

Abstract: A system for offshore operations include a column 1 extending above sea level from the seabed, which is connected by a bridge 2 to a semisubmersible offshore oil production platform 3. The connection of the bridge 2 to the platform 3 is achieved by an improved joint arrangement which permits relative rotation about both substantially vertical and horizontal axes to reduce loads transmitted to the column. The column 1 is connected by a universal joint arrangement 4 to a base on the seabed. The joint 4 has radially outwardly distributed joint surfaces which provides an axial passageway through the joint for risers. The joint arrangement includes a first main joint and a second normally unloaded ball joint which takes up the column load in the event of failure of the first joint.

Abstract: A method of constructing and assembling huge modules whose module frame includes sidewalls, a roof, trusswork frames and at least one deck structure secured within and to the module frame involves introducing a separately built deck structure into the module frame at floor level. The introduction is either through a temporary lower opening in a side wall frame, or from beneath the module frame. The deck structure is then positioned within the module frame, controllably elevated therein to a desired level and then secured to the module frame. This sequence is repeated as required such that additional separately built deck structures are similarly introduced into the module frame, positioned, elevated therein and secured thereto. After the desired number of deck structures has been installed, any lower opening in the sidewall frames is closed with trusswork braces.

Abstract: For rapid assembly of the deck of a drilling platform on a pipe scaffold, a connecting element made of two interlocking parts is described. The first part is in the form of a closing head integrated by casting into the end of a vertically standing pipe of the pipe scaffold, a ring-shaped horizontal support surface and a lifting bitt extending upward. The second part is in the form of a bell-shaped cover which envelops the lifting bitt. The cover on its upper surface is welded to the drilling platform, and at its underside includes a supporting surface which bears upon the supporting surface of the first part.

Abstract: Described herein are a system for securing and tensioning the tethers 12 of a tension leg platform 10 and a TLP installation method incorporating such a system. The tethers 12 preferably extend upward from the ocean bottom 16 to a position slightly below the bottom of the unballasted TLP hull 20. At least one tether tensioning tool 26 is situated within the hull 20 for lowering a tether extender 22 to each tether 12 and then biasing each tether-tether extender unit upward to tension the tether 12. The use of a removeable tensioning tool 26 avoids the need for a dedicated tensioning system for each tether 12. The tensioning system 28 of the present invention permits use of a simplified method for installing a TLP 10. Because the tethers 12 extend to an elevation which, at least initially, is below the draft of the TLP hull 20, the tethers 12 may be installed offshore prior to hull installation.

Abstract: A tension leg floating platform for offshore drilling has a plurality of tendons extending from the sea floor to the platform in tension. The upper connector for each tendon includes a housing with a conical shoulder located therein. A terminal segment on the upper end of each tendon extends through the housing. Dogs are carried on the shoulder of the housing, each having threads on the interior for mating threads formed on the terminal segment. A cam ring moves the dogs from an outer retracted position to an inner engaged position. The cam ring also will rotate the dogs relative to the terminal to mesh the threads of the dogs with the threads of the terminal segment.

Abstract: The present invention relates to an improved caisson structure which is adapted to support a production platform above the water and has its base on bottom and has a foot print or base which will pass through the drilling slot of a jackup rig. The caisson structure includes a large diameter caisson supported in a base structure including at least three base columns through which piling is placed and bracing extending between the columns and the caisson, a platform supported at the upper end of the caisson with production tubing and its casing extending upward through the caisson, and where desired, filled with concrete surrounding the casing within the caisson. The improved caisson structure can be used to surround and support an existing conductor pipe extending from a subsea wellhead to the surface or to surround a wellhead at the surface and the conductor which extends to such wellhead from a subsea well bore.

Abstract: The semi-submersible, deep-drafted platform includes a fully submersible lower hull, and a plurality of stabilizing columns which extend from the lower hull to an upper hull. At least one column has means adapted to reduce the water plane area within a portion of the dynamic wave zone of the column and to increase the natural heave period of the platform.

Abstract: A load transfer system and method for its use for mating an integrated deck structure onto an offshore platform substructure at an offshore location is disclosed. The load transfer system utilizes a probe extending downwardly from the integrated deck and adapted to mate with the substructure, and a shock-load absorbing system having a first spring with a linear compressive response and a second spring with a variable compressive response mounted in series between the integrated deck and the probe.

Abstract: An assembly for severing tubular piling used to support offshore platforms comprising a support or frame secured adjacent the open, upper end of the piling, a cutting string suspended from the support and comprised of a pipe string, a centralizer and an internal pipe cutter and a power swivel to rotate the cutting string to effect internal severing of the piling.

Abstract: A method of providing a nuclear steam supply system that is constructed to include a barge or flotation base as an integrated portion thereof. The system is tested for operability and safety at the factory and then towed along navigable coastal or inland waterways, or overseas to foreign locations, to a prepared foundation site at its point of use. The overall unit is so constructed and arranged as to permit the removal of top and side portions to permit passage under low bridges and through narrow locks without requiring disassembly of safety class piping and wiring. The method further provides for a complete nuclear power plant constructed on multiple barges at a separate factory site in parallel with plant site preparation, i.e., in estuaries or caves.