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: An off-shore oil production platform of the present invention includes an upper barge (1) stretching above the level of the sea. The barge (1) is connected to a completely submerged hollow lower base (3) by partially submerged connecting legs (2) forming a buoyance tank and stretching substantially vertical. The legs (2) along their submerged height includes at least two successive portions (10, 14). A first portion (10) with solid walls delimits a closed space and forms a buoyancy tank. A second portion (14) with openwork sidewall has an interior space open to a surrounding marine environment.

Abstract: The invention concerns a method of assembling sections (20) of support legs (2) of an oil platform in which an opening (11) is formed in the hull and in the lower part of the drive mechanism support framework (10) for each leg (2) to pass through, the sections (20) are engaged successively in the lateral opening (11) and the sections (20) are assembled to form each leg (2).

Abstract: A jack-up offshore drilling or production oil platform of the type including a barge (1) mounted so that it can be moved between a position for floating and a position for production out of the water. The barge is moved along bearing legs (2) by means of drive mechanisms (10) which each include at least two opposed sets (11). Each set is formed of a motor (12) associated with at least one set of reduction gears (13) driving, via a shaft, an output pinion (15) interacting with opposed racks (16) mounted on the bearing legs (2). Each rack (16) is provided along a length of the corresponding leg (2) necessary for moving the barge (1) between the position for floating and the production position. Also provided are devices for controlling the lowering of each leg (2) as far as a bearing structure (6) or as far as a seabed (7).

Abstract: The process for assembling long sections (11) of booms of support legs of an oil platform comprises machining an inclined flat surface (15) on the whole of the length of each main face of a rectangular plate (12), machining a groove behind each flat surface (15), machining an inclined chamfer on longitudinal edges of a stiffener (13), placing a stiffener (13) on each main face of the rectangular plate (12), welding each stiffener (13) to the rectangular plate (12), under a vacuum from the exterior by means of an electron beam, in the region of the chamfers and the flat surfaces so as to produce a section (11), and heat treating the section (11).

Abstract: Offshore oil drilling or producing platform comprising a hull (1) carried by legs (2) provided with feet (3) adapted to rest on the sea bed, characterized in that the walls of each of the legs (2) define a space opening onto the respective foot (3) in which are retracted anchoring piles (5) for the leg carried by the foot, each leg (2) being also provided in its upper part with support means (7) in vertical alignment with the piles within the space defined by the walls of the leg (2) for supporting a device for driving the piles into the sea bed.

Abstract: A platform comprises a hull mounted on legs such that it can be moved relative to the legs be by jack mechanisms disposed in a carrying structure. The jack mechanisms include a plurality of output gear pinions which cooperate with racks mounted along at least a part of the length of the legs. The hull is provided with a first device for applying an overload on the leg through the jack mechanisms. A second overload device is also provided an includes at least one additional load which is temporarily and directly lockable to each leg of the platform when the legs are being set on the sea bed.

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 system for maintaining a tightness between two parts rotatable relative to each other. The system includes at least two sealing units, with each of the sealing units having at least two possible states or conditions, namely, a first state or condition for ensuring a tightness between the two parts and a second state or condition wherein it does not ensure a tightness. Each sealing unit is deformable and includes a drive arrangement for intermittently actuating each of the sealing units.

Abstract: Disclosed is an inflatable value having a multilobed double wall, adapted to be opened out and retracted, and confining a layer of intermural air under pressure. The vault is constructed by assembling side by side a plurality of separate inflatable hollow beams, each of which includes at least two longitudinal panels which are sequentially connected together along at least two longitudinal edges. The panels of each beam are connected together and to panels of adjoining beams by a plurality of short quick-connect type female connectors. The joints between panels of each respective beam are made leaktight by including flexible membranes which span the respective joints. The inflatable vault according to the invention is particularly applicable to the covering of stadiums, swimming pools, tennis courts, restaurants, auditoriums, storage hangers and other large installations.

Abstract: A system for maintaining a tightness between two parts rotatable relative to each other. The system includes at least two sealing units, with each of the sealing units having at least two possible states or conditions, namely, a first state or condition for ensuring a tightness between the two parts and a second state or condition wherein it does not ensure a tightness. Each sealing unit is deformable and includes a drive arrangement for intermittently actuating each of the sealing units.

Abstract: The suspension device for the support legs of a jack-up oil platform having a hull movable along the legs includes a driving mechanism having a plurality of output gear pinions cooperating with racks mounted along at least a part of the legs. Each of the output gear pinions is drivable by an electric motor associated with a speed reducer which is pivotally mounted on a structure which is connected to the hull and has at least one bearing which allows a given angular movement of the speed reducer and each corresponding output gear pinion. Each speed reducer cooperates with an energy absorbing mechanism including at least one torsionally elastically yieldable support element connected to a corresponding speed reducer and affording a progressive absorption of shock particularly at the moment when the legs contact the sea floor.

Abstract: A support device for a leg (2) of an off-shore drilling jack-up platform including a separate heightener (3) adapted to be interposed between each leg of the platform and the sea bed so as to increase the depth of installation of the platform. Each heightener is provided with detachable means (4, 7, 11, 12) for connecting the heightener to the lower end (4) of a respective leg (2) which improves the strength thereof.

Abstract: A multi-passage swivel joint for simultaneous transfer of a plurality of separate fluids between two groups of conduits, the second group rotating about the first group has a plurality of sliding contact seals with a bundle of flow passages in deformable sheaths providing segregation continuity on the one hand for large rotations by sliding of the seals and on the other hand for small alternating angular motions by elastic deformation of at least one deformable sheath defining the flowpaths. The stiffness of the deformable sheath compared with the force required for causing the seals to slide being such that the coefficient of friction of the seals has a value such that sliding occurs before the maximum allowable deformation of the sheaths is reached.

Abstract: This method for raising a platform comprising a platform proper or deck carried by legs bearing on the sea bed comprises: fixing on each of the legs (2) of the platform a raising device (4) constituting a reinforcing device whose regions of fixing to the legs (2) are located on each side of a region of the leg to be cut; cutting the leg so as to divide it into a lower portion (2a) and an upper portion (2b); when all the legs have been cut, actuating the raising devices associated with each of the legs so as to raise the platform to an extent corresponding to the desired raising while controlling the attitude of the platform, and fixing between the ends of the portions (2a) and (2b) of each leg a heightening element (5) which once more interconnects the two portions of the leg, and removing the raising devices.

Abstract: A suitable system for connecting an anchored marine structure and a rotating moor arm of a floating facility in which a swivel combines for connecting the marine structure and the mooring arm has at least one plain journal bearing with at least one elastic pad arranged about the axis of the bearing such that the rotation of the mooring arm about the marine structure is achieved. Initially, rotation is achieved for large angular motions and significant rotations in particular those exceeding one complete turn by sliding of the journal bearing and secondly, for small alternating angular motions by elastic deformation of the pad. The stiffness of the pad is such, compared with the coefficient of friction of the journal bearing that the sliding threshold of the bearing is not reached.

Abstract: The locking device for a self-raising oil platform comprising a shell (1) mounted to be movable along legs (2) by means of raising mechanisms comprising output gear pinions cooperative with racks (3) mounted on at least a part of the length of the legs (2), comprises a toothed member (6) forming a counter-rack (6a) mounted on the shell of the platform, means (7) for shifting the toothed member (6) transversely of the direction of the rack with which the device is associated for engaging the teeth of the toothed member in the teeth of the rack (3) or for disengaging them from the teeth of the rack, clamping plates (13) connected to the toothed member and clamping counter-plates (15) connected to the platform, and means (20) for clamping the plates and counter-plates together so as to lock the toothed member (6) in position in the rack.