Unbalanced PDC drill bit with right hand walk tendencies, and method of drilling right hand bore holes

摘要

A rotary drill bit for cutting an earth formation is provided. The drill bit includes a bit body rotatable about its longitudinal axis. A cutting face is provided on the bit body, with a concave central region and a raised outer periphery terminating at bit shoulder. The bit shoulder is concentric with and substantially parallel to the longitudinal axis of the rotary drill bit. A plurality of bit stabilizing pads are circumferentially disposed about the bit's shoulder. A plurality of stationary cutter elements are fixedly mounted to the cutting face in a selected pattern to provide a region of high cutter density on one side of the cutting face, and a region of low cutter density on the other side of the cutting face. The drill bit cuts earth formations as the bit body is rotated about its central axis. The stationary cutter elements operate to cut into the lower side wall of the wellbore as the bit body is rotated, causing the rotary drill bit to walk to the right.