An apparatus for steering a rotating drill string

摘要

A stabilizer body is rotatably carried by the stabilizer sub, wherein the stabilizer body remains substantially stationary relative to the borehole as the drillstring rotates. At least one stabilizer blade is carried by the stabilizer body, the stabilizer blade being radially extendable from the stabilizer body and into engagement with the sidewall of the borehole. Each stabilizer blade is extendable and retractable from the stabilizer body independently of the others.