Offshore drilling apparatus
AssigneeDril-Quip, Inc.
InventorBruce J. Watkins
Life of this patent
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Abstract
There is disclosed an apparatus for use in drilling an offshore well wherein the upper end of a riser is intermittently supported from a floating vessel to permit the lower ends of additional pipe sections to be connected thereto and then lowered through the table for connection at its lower end to an underwater wellhead. The riser is supported from the vessel in such a manner as to absorb the load of the riser as an additional section is landed on its upper end, and then carry the load of the riser as the vessel tilts or rolls without imposing undue bending loads on the riser.
Claims6
For use in drilling an offshore well wherein the upper end of a riser is intermittently supported from a floating vessel to permit the lower ends of additional pipe sections to be connected thereto an apparatus comprising
- a housing adapted to be mounted on the vessel and having a generally vertical bore through which the riser may pass and an annular cylinder about the bore,
- radially inner and outer pistons sealably reciprocable within the cylinder and having respectively outer and inner spherical surfaces formed about a center common to the central axis of the bore of the housing,
- a ring having respectively inner and outer spherical surfaces conforming to and sealably slidable within those of the inner and outer pistons,
- means mounted on the ring for supporting a connection on the upper end of the riser, as the lower end of another pipe section is connected thereto, and
- then permit the riser to be lowered further, and means by which a chamber in the housing cylinder beneath the ring and pistons may be charged with a compressible fluid at a predetermined pressure so as to support the riser as the vessel tilts with respect to the riser.
Dependencies are inferred from the claim text.