Apparatus and method for remote adjustment of drill string centering to prevent damage to wellhead

In a subsea well assembly including a riser, a blowout preventer at a lower end of the riser, and a subsea wellhead at a lower end of the blowout preventer, an apparatus for supporting a drill string extending through the wellhead, comprising:

• a spool having an axis, an inner diameter, and a pair of windows located on opposite sides of the spool, wherein the spool is adapted to be coaxially mounted on the wellhead;
• a bit guide located in each of the windows of the spool;
• a linear actuator mounted adjacent to each of the bit guides in the spool, wherein the linear actuators move the bit guides radially relative to the spool between an open position, wherein the bit guides define a maximum diameter that is substantially equal to the inner diameter of the spool, a closed position, wherein the bit guides define a minimum diameter that is smaller than the inner diameter of the spool;
• and wherein
• the bit guides are variably adjustable between the open and closed positions to define a plurality of diameters therebetween or supporting the drill string located within the wellhead.

A method for drilling a subsea well through a subsea assembly including a riser, a blowout preventer at a lower end of the riser, and a subsea wellhead at a lower end of the blowout preventer, the method comprising:

• (a) mounting an upper bit guide at the lower end of the riser and above the blowout preventer;
• (b) mounting a lower bit guide above the wellhead and below the blowout preventer;
• and
• (c) lowering a drill string with a drill bit through the riser, blowout preventer and a bore of the wellhead, and centering the drill bit in the bore with the upper and lower bit guides.