Differential pressure mover

摘要

A downhole tool for conveyance within a wellbore extending into a subterranean formation. The downhole tool comprises a moveable member comprising a first surface defining a moveable boundary of a first chamber, and a second surface defining a moveable boundary of a second chamber. The downhole tool further comprises hydraulic circuitry selectively operable to establish reciprocating motion of the moveable member by exposing the first chamber to an alternating one of a first pressure and a second pressure that is substantially less than the first pressure.