Abstract: A method of commissioning one subsea hydrocarbon well terminating by a wellhead, wherein, from a petroleum drilling rig, the method includes: screwing double-walled pipe segments together in mutual succession to form a thermally insulated floor-to-surface 1 hydrocarbons, and an outer pipe, between which pipes a thermally insulating material is disposed; connecting the floor-to-surface link pipe to wellhead; and extracting the hydrocarbons via the floor-to-surface link pipe to the drilling rig on the surface.

Abstract: A method of commissioning one subsea hydrocarbon well terminating by a wellhead, wherein, from a petroleum drilling rig, the method includes: screwing double-walled pipe segments together in mutual succession to form a thermally insulated floor-to-surface 1 hydrocarbons, and an outer pipe, between which pipes a thermally insulating material is disposed; connecting the floor-to-surface link pipe to wellhead; and extracting the hydrocarbons via the floor-to-surface link pipe to the drilling rig on the surface.

Abstract: The invention relates to a device reinforcing circumferential welds 8 which join two contiguous pipes 6 and 7 in order to increase the fatigue life of said welds by reducing mechanical stresses in them when being subjected to periodic bending. The device comprises a rigidifying element 10 which is firmly joined to said pipes by a connection means 11, 13, said bush being made of the same material as the pipes. The rigidifying element 10 consists of a bush slipped over the two pipes 6, 7 opposite the weld 8. The connection means is a hardening material 11 such as resin or cement which is injected between bush and pipes and which is confined at this site by shaping, in particular cold-forming, the bush's ends. The application is to offshore hydrocarbon conveyance conduits subjected to periodic loads.

Abstract: The invention relates to a device reinforcing circumferential welds 8 which join two contiguous pipes 6 and 7 in order to increase the fatigue life of said welds by reducing mechanical stresses in them when being subjected to periodic bending.

Abstract: A line pipe with a double casing is especially used in transporting oil products. In a preferred embodiment, such a pipe is characterized in that, in a sealed annular space, located between an inner tube and an outer tube both coaxially arranged inside each other, there is included a self-sustaining plate made of open pore-microporous material, which is flexible enough to be externally wound around the inner tube. This plate is preferably less in thickness than said annular space such that a passageway is left free between the former and the outer tube whereby low pressure is maintained.