Marine riser tower
AssigneeAcergy France SAS
InventorVincent Marcel Ghislain Alliot
Life of this patent
Estimating the term…
Abstract
The invention provides a marine riser apparatus (1) for use in the production of hydrocarbons from offshore wells and an associated method of installation of the apparatus at sea. The riser tower comprises rigid pipelines arranged in a riser tower bundle (2) and extending from a wellhead on the seabed (4) to a point below the sea surface where they are connected to flexible jumpers (3) which extend from the tower structure to connect the tower structure to a surface vessel or platform (5). The riser apparatus further comprises a buoyancy device (7) attached to the riser tower bundle, such that the buoyancy device is located above and exerts a buoyancy force on the riser tower, the buoyancy module also supporting an intermediate section of at least one of the jumpers.
Claims39
A marine riser apparatus for use in the production of hydrocarbons from offshore wells, wherein said riser apparatus comprises:
- a riser tower comprising a substantially rigid bundle of rigid conduits, the riser tower having a first end at which the rigid conduits are connected to one or more flexible conduits and having a second end from which the rigid conduits are adapted to extend to connecting structures on the sea bed;
- a buoyancy device tethered to the first end of the riser tower and adapted to be located above the riser tower when the riser tower and the buoyancy device are underneath a sea surface;
- wherein an intermediate section of at least one of the flexible conduits is supported by the buoyancy device.
A method of installing a marine riser apparatus comprising:
- towing a riser tower to an installation site, said riser tower comprising a substantially rigid bundle of rigid conduits, the riser tower having a first end and a second end, wherein the riser tower is tethered at its first end to a buoyancy device;
- upending the riser tower by sinking a second end of said riser tower structure to the seabed at the installation site;
- anchoring the tower structure to the seabed;
- deballasting the buoyancy device;
- connecting one or more flexible conduits to the top of the tower structure;
- passing a first end of at least one of said one or more flexible conduits over the buoyancy device;
- and
- attaching a second end of said at least one or more flexible conduits to a surface structure.
Dependencies are inferred from the claim text.