| 摘要 |
<p>An underreamer (10) for forming a cavity (42) from within a well bore includes a housing (12) adapted to be disposed within the well bore. The underreamer includes at least one cutter (14), wherein each cutter has a first end and a second end. The first end of each cutter is pivotally coupled to the housing. The underreamer also includes an actuator (16) slidably positioned in the housing, wherein the actuator has a first end and a second end. The underreamer includes an enlarged portion (20) of the actuator proximate the second end of the actuator. A first axial force applied to the actuator is operable causing the enlarged portion to contact each cutter and extend the second end of each cutter radially outward relative to the housing from a retracted position to a first position. A second axial force applied to the underreamer may be operable to further extend the second end of each cutter radially outward relative to the housing from the first position to a second position.</p> |
