Offshore drilling method and apparatus

Claim 1

APPARATUS FOR USE WITH A FLOATING VESSEL FOR DRILLING A WELL IN THE FORMATION UNDERLYING A BODY OF WATER, COMPRISING IN COMBINATION: A BOTTOM STRUCTURE FIXED ON THE FORMATION, AND UNDERWATER FLOAT OF CONTROLLABLE BUOYANCY, A TUBULAR MEMBER FIXED TO SAID STRUCTURE AND EXTENDING UPWARD TO SAID FLOAT, SAID TUBULAR MEMBER HAVING LONGITUDINALLY SPACED LATERALLY FLEXIBLE JOINT THEREIN, TUBULAR APPARATUS SECURED RELATIVE TO THE FLOAT AND RESTING THEREON AND INCLUDING A BLOWOUT PREVENTION DEVICE, SAID TUBULAR APPARATUS EXTENDING UPWARD ABOVE SAID FLOAT AND BEING FIXED AT ITS UPPER END TO SAID FLOATING VESSEL AND HAVING A TELESCOPIC JOINT THEREIN, THE BUOYANCY OF THE FLOAT SERVING TO MAINTAIN SAID TUBULAR MEMBER IN SUFFICIENT TENSION TO RETAIN SAID FLOAT IN SUBSTANTIAL ALIGNMENT WITH SAID VESSEL AND SAID BOTTOM STRUCTURE AND SERVING TO SUPPORT THE WEIGHT OF SAID TUBULAR APPARATUS AND MEANS FOR OPERATING DRILLING TOOLS FROM THE FLOATING VESSEL THROUGH THE INTERIOR OF THE TUBULAR APPARATUS, UNDERWATER FLOAT AND TUBULAR MEMBER AND SAID BOTTOM STRUCTURE.