| 摘要 |
<p>A steerable drilling system comprising a bottom hole assembly (18) including an upper section (22) and a steering section (24), a swivel (26) permitting adjustment of the orientation of an axis of the steering section (24) relative to that of the upper section (22), a downhole motor operative to drive the steering section (24) for rotation relative to the upper section (22), and a plurality of actuators (34) operable to control the orientation of the axis of the steering section (24) relative to that of the upper section (22), the (actuators 34) being mounted upon one of the steering section (24) and the upper section (22,) a high speed sliding contact being formed between the actuators (34) and the other of the steering section (24) and the upper section (22).</p> |
