Abstract: A seal for sealing between two mating faces that are curved. The seal includes a groove formed in one of the faces for encircling a passageway that terminates at the face. The groove has a depth that varies along the diameter of the groove with the curvature of the face. The base or bottom of the groove is located in a single plane. An elastomeric seal ring is located in the groove. The seal ring also has a variable cross-sectional thickness that varies around the diameter of the ring corresponding to the depth of the groove. The seal ring has an annular band that fits within a counterbore in the groove to retain the seal ring.

Abstract: A supporting connection system for a riser extending between a floating vessel and a subsea well utilizes a termination head that removably fits within a termination housing. The termination head and housing have radial ports that register with each other to transmit fluid between the vessel and the subsea well. A sliding sleeve is located in the radial port of the termination housing. The sleeve is reciprocated by hydraulic pressure between an open position removed from the termination head and a closed position with its forward end located inside the termination head radial passage. The forward end of the sliding sleeve seals within the termination head passage.