Method and apparatus for installing underwater flowlines

Abstract

A method and apparatus for installing a length of underwater pipe, such as a petroleum flowline bundle, between two subsea stations, for example a subsea oil or gas wellhead and a subsea manifold to establish a fluid conduit between these stations. The flowline bundle is transported by a surface vessel to location where downhaul cables are then brought to the surface from the underwater stations by means of call-up buoys. A flowline mating vehicle is connected to each end of the flowline bundle, the downhaul cables are attached to powered winches contained in these vehicles, and the bundle is then hauled downward by the vehicles to the subsea stations where it is connected to the terminals of the flowlines at these stations by a remotely actuated clamping system. The flowline mating vehicles are then released from the flowline bundle and the stations to be retrieved at the surface for reuse. The invention is applicable to both "wet" and "dry" wellhead completions, and includes apparatus for accomplishing these completions entirely by remote control from the surface.

Dependencies are inferred from the claim text.