CONTROLLING DRILL BIT TORQUE

摘要

A method and apparatus for controlling the rotational torque of a drill bit powered by a downhole motor. The downhole motor is suspended from a hydraulic ram at the lower end of a string of drill pipe. A torque sensor detects the reactive torque in the downhole motor during drilling. In response to the detected torque level, pressurized drilling fluid from the downhole motor is provided to the hydraulic ram thereby varying the weight applied to the drill bit in order to maintain a constant torque level.