Den Norske Stats Oljeselskap A.s.

Atle B Ingebrigtsen

J&oslash;rgen Eide

K&aring;re Breivik

Jens R Odegaard

A swivel assembly for installation at a well for subsea production of oil or gas and adapted to be connected to a production vessel at the sea surface. The swivel assembly comprises a main fluid swivel having at least two paths and an electric/hydraulic auxiliary swivel for signal communication and power transfer. The fluid swivel is provided with a rotatable swivel housing at the top of a stationary christmas tree, preferably comprising a small number of valves, such as a production master valve and an annulus master valve. The paths are through-running vertically in the central core member of the fluid swivel so as to make possible well intervention from the upper side of the fluid swivel.

Swivel

A system for offshore production of oil or gas, comprising a surface vessel having a means for maintaining a desired position and orientation, a bottom installation at the seabed for at least two production wells, and risers for connecting the bottom installation to the vessel. The vessel is provided with drilling equipment for wells at the seabed and with process equipment for produced oil or gas. The bottom installation comprises a template having its foundation at the seabed and being provided with a manifold unit and is designed with at least two well head sections adapted for installing associated Christmas trees. A drill string is adapted to extend from the drilling equipment on the vessel to an operation module at the bottom installation, and a product riser is adapted to connect the operation module to the process equipment on the vessel.

System, vessel, seabed installation and method for producing oil or gas

Subsea well arrangement for offshore production of oil or gas, comprising a wellhead, a christmas tree mounted on the wellhead and at least one riser for connection with a production vessel at the sea surface. At the top of the christmas tree there is provided a swivel device communicating with the christmas tree, and the swivel device is provided with preferably laterally directed connecting members for risers or hoses and for an umbilical or control cable.

Subsea well

Subsea unit for offshore production of oil or gas, comprising one or more wellheads with associated christmas trees provided on or at a bottom frame (template). On or at the template there is mounted a swivel device, having fluid connection to the christmas tree or trees and being provided with connection members for risers and an umbilical or control cable from a production vessel at the sea surface.

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Nesttun, Norway

Atle B Ingebrigtsen