| 摘要 |
A Method and Apparatus for drilling a curved planar borehole, wherein a drill bit is mounted at the lower end of a drill string which extends downwardly into the borehole, and wherein fluid under pressure is pumped through the drill string, a drilling motor for rotating the drill bit, a specialized drill sub mounted in the drill string above the drilling motor, an eccentric sleeve rotatably mounted over the drill sub, an alignment mechanism attached to the eccentric sleeve, a deflection device mounted in the sleeve for bearing against one side of the wellbore, whereby, when fluid under pressure is introduced into the drill sub, the deflection device will move outwardly against the side of the wellbore, the alignment mechanism being such that the drill sub can rotate independently of the eccentric sleeve to prevent reactive torque from the drilling motor from being exerted against the sleeve and the deflection device.
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