Steerable rotary drilling system

专利名称：Steerable rotary drilling system

发明人：JOHN DENZIL BARR,MICHAEL KING RUSSELL申请号：AU1851192申请日：19920624公开号：AU666850B2公开日：19960229

摘要：A system for maintaining a downhole instrumentation package in a rollstabilised orientation with respect to a drill string comprises an instrument carrier (812)which is mounted within a drill collar (810) for rotation about the longitudinal axis of thecollar. An impeller (815) is mounted on the instrument carrier so as to rotate the carrierrelatively to the drill collar as a result of the flow of drilling fluid along the drill collarduring drilling. The torque transmitted to the instrument carrier (812) is controlled, inresponse to signals from sensors in the carrier which respond to the rotationalorientation of the carrier, and input signals indicating the required roll angle of thecarrier, so as to rotate the carrier (812) in the opposite direction to the drill collar (810)and at the same speed, so as to maintain the carrier non-rotating in space and hence rollstabilised. The torque may be controlled by controlling a variable coupling (851,852)between the impeller and the carrier and/or by controlling a brake (857), for example inthe form of a differential gear mechanism, between the carrier and the drill collar.

申请人：CAMCO DRILLING GROUP LIMITED

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