Abstract: A buoyancy system for a floating platform includes at least one composite buoyancy module coupled to a riser. The composite buoyancy module is sized to have a volume to produce a buoyancy force. The composite buoyancy module may include a vessel with a composite vessel wall. A layer of buoyant material fills the volume of the vessel between a stem pipe and the vessel. The buoyant material may be foam. The layer may include a plurality of discrete sections interconnected to form the layer. Protrusions and indentations may be formed in the sections to mate and interlock the sections.

Abstract: Hybrid pipe for deep water, comprising a metallic rigid central part having an upper end of which is connected to an upper portion of flexible pipe of predetermined length and having a lower end of which is connected to a lower portion of flexible pipe of a length at least equal of the length of the upper portion of flexible pipe. The lower portion may have a wave-shaped form to absorb motion. The wave is formed by buoyant members on the lower flexible portion by an arch tethered to the sea bed on which the wave-shaped portion rests.

Abstract: A riser system connecting a oil or gas well head and a surface vessel comprises a first riser section maintained substantially vertically under tension, attached for example by a tension cable to a constant load tensioner means mounted on the vessel, and a flexible second riser section arranged above the first riser, the second riser being able to flex to accommodate movements in the surface vessel. The second riser section includes a curvature limiter, achieved for example by making the riser from a material of variable stiffness along the riser's length. An emergency disconnect valve is provided between the lower riser section and the upper flexible section. An alternative curvature limiter comprises a plurality of discrete collars which are connected together and surround the outer diameter of the second riser.

Abstract: The invention is a system used for production of petroleum effluents situated at great water depths. The system includes an intermediate floating station situated below the surface at a depth selected according to the pressure of the effluent at the outlet of wellheads situated on the station, production risers communicating with the well to be worked, an anchor including production risers, a pump situated on the floating station which transfers the effluent to a processing or destination site, a transfer which transfers the effluent between the floating station, the water bottom and a final platform or a processing plant, and an energy source providing necessary energy to the various equipments installed on the floating station.