Patent ID: 7150324

Claim:
A system for riserless drilling of a subsea borehole from a platform and through a subsea wellhead and into a cased borehole, the system comprising: a lightweight drill string suspending a bottomhole assembly and extending from said platform downwardly through a depth of water, through the subsea wellhead and into the cased borehole, said lightweight drill string including a non-jointed, continuous tubing made of a lightweight metal or a lightweight composite material; a first limiter disposed on the platform and limiting the range of bending motion of said drill string adjacent the platform as the drill string passes through the first limiter during drilling; a second limiter having a bellmouth disposed on the wellhead limiting the range of bending motion of said drill string adjacent the cased borehole as the drill string passes through the second limiter during drilling; and wherein said segmented bend restrictor includes a flexible lining disposed therethrough.