Three dimensional steerable system

摘要

An apparatus for steering a bit while drilling a borehole, comprising: a first housing (26) connected to a second housing (28) by a universal joint (30), said first housing having a first axis (74) and said second housing having a second axis (72); a first cam member (80) mounted on said first housing; a plurality of second cam members (86a,86b,86c) movably mounted on said second housing and engaging said first cam member; and said second cam members having a first position with respect to said first cam member forming a first angle and a first azimuth between said first and second axes and a second position with respect to said first cam member forming a second angle and a second azimuth with respect to said first cam member.