STEERABLE UNDERREAMER/STABILIZER ASSEMBLY AND METHOD

摘要

A bottom hole assembly includes a drill bit, a stabilized underreamer assemb ly located behind the drill bit, and a drilling assembly. A method to drill a formation includes positioning a stabilized underreamer assembly behind a drill bit, positioning a drilling assembly behind the stabilized underreamer assembly, and rotating the drill bit and stabilized underreamer assembly with the drilling assembly. A stabilized underreamer located between a directional drilling assembly and a drill bit includes at least one arm assembly extending from t he stabilized underreamer assembly, wherein the arm assembly includes a stabilizer portion and an underreamer cutting structure.