EXPANDABLE REAMERS FOR EARTH BORING APPLICATIONS

摘要

An expandable reamer apparatus for drilling a subterranean formation incl udes a tubular body (108), one or more blades (101, 102, 103), each blade po sitionally coupled to a sloped track (148) of the tubular body, a push sleev e (115) and a drilling fluid flow path extending through an inner bore of th e tubular body for conducting drilling fluid therethrough. Each of the one o r more blades includes at least one cutting element configured to remove mat erial from a subterranean formation during reaming. The push sleeve is dispo sed in the inner bore of the tubular body and coupled to each of the one or more blades so as effect axial movement thereof along the track to an extend ed position responsive to exposure to a force or pressure of drilling fluid in the flow path of the inner bore. The track is sloped upwardly and outward ly at an acute angle (180).