Abstract: A surface assembly that communicates with subsea structures and includes a working deck on a floating structure. The working deck has an aperture extending axially therethrough. A riser extends from a subsea location to the working deck and through the aperture. The surface assembly includes a frame extending circumferentially around the riser so that the frame moves axially with the riser. The assembly also includes a tensioner assembly connected between the working deck and the frame. The tensioner assembly includes a piston slidably carried in a piston chamber, a piston rod extending from the piston and away from the piston chamber, and a shroud enclosing the piston rod. The shroud has a plurality of segments with at least one of the shroud segments being movable in unison with the piston rod.

Abstract: A tensioner for an offshore structure has inner and outer barrels engaging each other for movement between retracted and extended positions. The barrels are filled with gas pressure. A primary seal is located between the inner and outer barrels at the open end of the inner barrel. An annular lubricant reservoir is mounted to an interior wall surface of the inner barrel at the open end of the inner barrel. A lubricant port extends from the lubricant reservoir through the inner barrel to a high pressure side of the primary seal for dispensing lubricant between the inner and outer barrels. A fill tube leads from the reservoir to the exterior of the inner barrel for replenishing lubricant.

Abstract: A surface assembly that communicates with subsea structures and includes a working deck on a floating structure. The working deck has an aperture extending axially therethrough. A riser extends from a subsea location to the working deck and through the aperture. The surface assembly includes a frame extending circumferentially around the riser so that the frame moves axially with the riser. The assembly also includes a tensioner assembly connected between the working deck and the frame. The tensioner assembly includes a piston slidably carried in a piston chamber, a piston rod extending from the piston and away from the piston chamber, and a shroud enclosing the piston rod. The shroud has a plurality of segments with at least one of the shroud segments being movable in unison with the piston rod.

Abstract: A tieback connector connects a riser between a subsea wellhead housing and a floating platform. The tieback connector has a tubular body that stabs into and seals with a casing hanger. A latch member on the tieback connector engages a locking profile to secure the tieback connector to the wellhead housing. A sleeve is slidably carried on the tubular body between a running-in position and a set position. The lower end of the sleeve lands on an upper rim of the casing hanger prior to the seal engaging the seal surface. Continued downward movement of the tubular body relative to the sleeve causes the seal to engage the seal surface and the sleeve to move to the set position. The sleeve has upper end that engages a lower end of the latch member to limit any upward movement of the casing hanger in the wellhead housing.

Abstract: Keel joint assemblies are described that permit a degree of rotational movement of a riser within the keel of a floating vessel and greatly reduce the amount of stress and strain that is placed upon the riser, as well. Keel joint assemblies described provide a limiting joint between the riser and the keel opening that permits some angular rotation of the riser with respect to the floating vessel. Additionally, the limiting joint permits the riser to move upwardly and downwardly within the keel opening, but centralizes the riser with respect to the keel opening so that the riser cannot move horizontally with respect to the keel opening. In described embodiments, the limiting joint is provided by a single annular joint that allows that riser to move angularly with respect to the can. In some embodiments, the keel joint assembly incorporates a cylindrical stiffening can that radially surrounds a portion of the riser and is disposed within the keel opening.

Abstract: Keel joint assemblies are described that permit a degree of rotational movement of a riser within the keel of a floating vessel and greatly reduce the amount of stress and strain that is placed upon the riser, as well. Keel joint assemblies described provide a limiting joint between the riser and the keel opening that permits some angular rotation of the riser with respect to the floating vessel. Additionally, the limiting joint permits the riser to move upwardly and downwardly within the keel opening, but centralizes the riser with respect to the keel opening so that the riser cannot move horizontally with respect to the keel opening. In described embodiments, the limiting joint is provided by a single annular joint that allows that riser to move angularly with respect to the can. In some embodiments, the keel joint assembly incorporates a cylindrical stiffening can that radially surrounds a portion of the riser and is disposed within the keel opening.