Abstract: A monobore completion/intervention riser system for providing a conduit for communication fluids and wireline tools between a surface vessel and a subsea well having a tubing hanger located therein, the tubing hanger including a production bore and an annulus bore, wherein wireline tools may be lowered through a riser bore 48 to either the tubing hanger production bore 68 or the tubing hanger annulus bore 70 through operation of a bore selector 56, and fluids may be produced from the well to the surface vessel through the production bore 52, 60, 64, 68 and the riser bore 48 by sealing off the annulus bore 66, 70.

Abstract: A single tubular member, or monobore riser, is provided for tubing hanging operations via a drilling riser and BOP, where wireline and/or coiled tubing deployed tools may be directed into production and annulus bores via a dual bore safety package and a dual bore selector and where various circulation modes may be established in cooperation with the choke and kill conduits in the BOP stack or with a length of tubing through the monobore riser in cooperation with selectively operable valves in the production and annulus bores of the safety package, a retainer valve in a single bore at the top of the dual bore selector, and by means of BOP rams capable of closing about a spool of the safety package and with a side outlet in the safety package. For Xmas Tree (XT) operations, the identical monobore riser is provided for surface communication to a dual bore selector and dual bore Riser Safety Package (RSP) secured to the top of the XT.

Abstract: A tool for setting the packoff between the casing hanger and the wellhead utilizes differential area pistons. The tool has a mandrel which connects to a string of drill pipe. The mandrel carries a body and is axially movable relative to the body. A setting sleeves is carried by the body for connection to the packoff. A setting sleeve piston is carried by the body for relative movement relative to the body. A mandrel piston is carried by the mandrel for movement with the mandrel. Passages in the body communicate the mandrel piston with a setting sleeve piston and contain an incompressible fluid. Axial movement of the mandrel causes the pressure to increase to drive the setting sleeve piston downward to set the packoff.

Abstract: A method and apparatus for remotely replacing damaged guideposts attached to a subsea structure are provided. A receptacle is permanently attached to the subsea structure. The guidepost is inserted into the receptacle and is releasably connected thereto by one or more radially-oriented, spring loaded lock pins. Damaged guideposts are removed by applying an upward vertical force to the guidepost sufficient to shear the lock pin or lock pins. The upward vertical force is applied by a replacement tool capable of being remotely operated from the surface of the body of water. Following removal of the damaged guidepost, a new guidepost is inserted into the receptacle. Lock pins mounted in the new guidepost retract into the guidepost as it is being inserted. When fully inserted, the lock pins extend and engage a retaining groove formed in the receptacle thereby firmly locking the new guidepost in place.

Abstract: An apparatus and method are disclosed for aligning equipment lowered from the ocean surface with a fixed subsea structure without the use of guidelines. The apparatus comprises a guide frame including primary and secondary members, a mating guide base including primary and secondary members, vertical channeling means and rotational engagement means. In the practice of the method, the frame is generally positioned above the base using known means of limited precision. Using remote means, the frame is first lowered to vertically channel the primary members into alignment, then rotated until the secondary members are engaged and finally lowered further to fully land the frame on the base.