SYSTEM FOR STEERING A DRILL STRING

摘要

In one aspect of the present invention, a drill bit assembly has a body portion intermediate a shank portion and a working portion The working portion has at least one cutting element and at least a portion of a shaft is disposed within the body portion and protrudes from the working portion The shaft has a distal end rotationally isolated from the body portion and is in communication with a subterranean formation A motor is adapted to rotationally control the distal end.