Patent ID: 6161620
Filing Date: 2000-12-19
Classification: E21B

Abstract:
A deepwater riser assembly for use with a spar platform, comprising:a riser connecting subsea equipment to a surface wellhead of the spar platform;a buoyancy can assembly, comprising:an open ended buoyancy can tube surrounding the upper end of the riser;an upper seal effectively closing the annulus between the riser and the buoyancy can tube; anda load transfer connection between the buoyancy can tube and the riser;a pressure charging system communicating with the annulus between the riser and the buoyancy can tube at a location below the upper seal;a bottom centralizer connected to the riser at a level corresponding with the lower end of the buoyancy can tube and securing the alignment of the riser within the buoyancy can tube; anda plurality of buoyancy can guides mounted on the spar platform and slidingly receiving the exterior of the buoyancy can tubes to secure against relative transverse motion, but to permit relative axial motion.