Patent ID: 6615921
Filing Date: 2003-09-09
Classification: E21B

Abstract:
In a subsea well assembly including a riser, a blowout preventer at a lower end of the riser, and a subsea wellhead below the blowout preventer, an apparatus for protecting the wellhead from a drill string and drill bit lowered therethrough, comprising:a spool having an axis and an inner diameter, the spool being coaxially mounted to an upper end of the wellhead, the blowout preventer being connected to an upper end of the spool; and a bit guide mounted to the spool and radially movable relative thereto between an open position, wherein the bit guide defines a first opening having a first diameter that is substantially equal to the inner diameter of the spool, and a closed position, wherein the bit guide defines a second opening having a second diameter that is smaller than the inner diameter of the spool.