Abstract: A method for making a quasi-incompressible phase-change material (PCM) having low thermal conductivity includes combining with a phase-change material (PCM) in liquid state a thickening agent selected to reduce significantly thermal convection, the formed material having, depending on the combinations performed, a gelled structure or a colloidal dispersed system. The PCM may be a mixture of chemical compounds of the family of alkanes, paraffins, waxes, fatty alcohols, fatty acids and the like, and the thickening agent may be organic (aromatic ureas), organometallic (alkaline or alkaline earth soaps) or purely inorganic (silica, silico-aluminates such as bentonite made oleophilic). The material is useful for thermal isolation of containers or pipes, and in particular for thermal insulation of hydrocarbon carrying pipes.

Abstract: The present invention relates to a device for the heat insulation of at least one underwater pipe (1) intended to be laid on the sea bed at great depth, comprising an insulating coating surrounding the latter and a protective envelope (3), characterized in that said insulating coating comprises a virtually incompressible liquid/solid phase change material (4) with a melting temperature T0 higher than that T2 of the medium surrounding the pipe in operation and less than that T1 of the effluents circulating in the pipe, and said material (4) preferably being impregnated in an absorbent matrix (2) surrounding the pipe (1), preferably nearest its outer surface, which protective envelope (3) is resistant and deformable and ensures a containment against and about said insulating coating.

Abstract: A device for laying submarine pipeline from a vessel at sea. The device has a support or laying tower that can be inclined in a variable manner. The device has a workstation for assembling the successive parts of an offshore pipeline with the workstation attached to the vessel independently of the tower and is displaceable along the vessel to assemble the successive parts of the pipeline.

Abstract: The present invention relates to a liquefied gas storage barge in the form of a concrete floating structure. The barge of the invention is essentially constituted by a floating structure (1) of reinforced and prestressed concrete containing tanks (2) for liquefied gas. Said tanks (2) are cylindrical tanks each having a cross-section perpendicular to its longitudinal axes that comprises a preferably circular curved portion (3) corresponding to the bottom of said tank, said portion being preferably a bottom half-circumference resting directly on the concrete bottom of the barge, which barge bottom is in the form of adjacent part-cylindrical troughs (3), each part-cylindrical trough having the same preferably circular, partially curved section in register with the bottom of each tank.

Abstract: A clamp system installed on a floating support for holding a pipe under tension, the system comprising a tubular element having a plurality of friction shoes. Each of the shoes is mounted at the end of a piston of a hydraulic actuator. The actuators and shoes are disposed in a plurality of planes. The pistons move in translation in a direction perpendicular to the longitudinal axis of the tubular element. Each actuator includes a mechanical lock for locking the piston in its extended position.

Abstract: An apparatus for holding and guiding a floating riser relative to a floating support. The apparatus includes a guidance mechanism secured to the floating support for enabling the riser to rotate about a horizontal axis perpendicular to a longitudinal axis of the riser; and for enabling the riser to slide longitudinally along the longitudinal axis and lateral displacement of the riser to be guided in a horizontal plane perpendicular to the longitudinal axis of the riser. The guidance mechanism includes friction pads mounted on a pad support for enabling the pads to pivot. The pads preferably cooperate with wheels such that the wheels bear against the riser and enable it to slide, and the riser comes to bear against the pads only when the wheels are moved away under the effect of lateral displacements of the riser.

Abstract: The present invention relates to a floating support of the type having a cavity (1) within which a plurality of risers (2) can be positioned. According to the invention, the cavity (1) has a plurality of compartments (3) at the ends of which said risers (2) are in a production position (4), said compartments communicating with a central channel (5) at the end of which there is situated (6) a drilling derrick (7), said compartments being disposed transversely relative to said central channel (5).

Abstract: The present invention relates to a device for the heat insulation of at least one underwater pipe (1) intended to be laid on the sea bed at great depth, comprising an insulating coating surrounding the latter and a protective envelope (3), characterized in that said insulating coating comprises a virtually incompressible liquid/solid phase change material (4) with a melting temperature T0 higher than that T2 of the medium surrounding the pipe in operation and less than that T1 of the effluents circulating in the pipe, and said material (4) preferably being impregnated in an absorbent matrix (2) surrounding the pipe (1), preferably nearest its outer surface, which protective envelope (3) is resistant and deformable and ensures a containment against and about said insulating coating.

Abstract: The present invention relates to a bottom-to-surface link system for an underwater pipe installed at great depth, the system comprising: firstly a vertical tower constituted by at least one float (5, 14) associated with an anchor system (6, 8, 16) and carrying at least one vertical riser (9, 15) suitable for going down to the sea bed (18); and secondly at least one link pipe (4, 3) extending from said float (5, 14) to a surface support (1). According to the invention, said link pipe is a riser whose wall is constituted by a rigid steel tube, and said float (5, 14) is installed at a depth situated below the last thermocline (29).

Abstract: The laser apparatus (L, G, T) is placed on a stand (B) which carries the support for the working head (T) of the apparatus in rotary manner, and the apparatus together with its stand are housed in a container (C) through which the tube passes, which container is fixed to the tube while work is taking place, the mass of the container together with that of its contents considerably damping the transmission of stresses from the tube to the working head.

Abstract: The tube is hammered by means of a hydraulic or an electromagnetic hammer pressed against a pile-driving head situated at the bottom of the tube. The bottom of the tube is preferably provided with a hammering bearing surface and a removable head is used that is suitable for resisting laterally on said bearing surface. The invention is particularly applicable to providing piles or stakes, particularly for a foundation.

Abstract: This invention relates to recovering the substructure of an offshore platform. A floating barge is used comprising a ballastable hull having a deck suitable for receiving the substructure in a substantially horizontal position and including ballastable floats disposed above the deck to right and to left of the intended location for the substructure. The hull and the floats are ballasted so that although it does not sink, the barge moves down into the water and tilts into a position where its deck can be moved against one of the faces of the substructure. The barge is fixed to the substructure, the substructure is disconnected from the sea bed, ballast is removed from the barge to return it to a position where it is floating and carrying the substructure, and the barge is moved to the desired location for unloading the substructure. The invention is applicable to recovering substructures of large dimensions.

Abstract: A method of fabricating the lines of a taut-line platform and of prepositioning them prior to final fixing by making use of a ballastable spacer frame associated with shuttles for guiding the lines as they are constructed including preparing a floating spacer frame that is submersible by ballasting, preparing a number of shuttles of a horizontal size approximate to the group of openings through the frame to receive the same with the shuttles having releasable upper and lower mechanisms for fixing to the frame in the floating platform respectively and suspended from a second winch, being guided against rotation and having horizontal plain thrusters. After exact orientation of a platform frame assembly relative to a base, the lowering of the frame shuttle assembly is effected by ballasting the platform under guidance and shuttle thruster operation with stowing of the frame on the base occurring under conditions in which the ends of lines are permitted to heave freely in the openings of the frame.