Patent attributes
An expandable underreamer apparatus disposed on a distal end of a drillstring and configured to drill a formation includes a substantially tubular main body adjacent a cutting head, the main body providing at least one axial recess configured to receive an arm assembly, and the arm assembly configured to translate between a retracted position and an extended position. The apparatus further includes a plurality of cutting elements disposed on the arm assembly, and a plurality of wear indicators imbedded in at least one arm assembly and positioned behind the cutting elements with respect to a direction of rotation of the arm assembly, wherein the wear indicators are configured to provide an increased torque to the drillstring upon contacting the formation.
