THE METHOD OF AND APPARATUS FOR DETERMINING THE PATH OF A WELL BORE UNDER DRILLING CONDITIONS

摘要

Apparatus for determining the path of a well bore during drilling, comprises an inertial measurement unit (12) for providing data from which position, velocity and attitude can be derived, the measurement unit comprising a plurality of inertial sensors mounted on a platform assembly which is, in us e, disposed within a drill string (6), and a drive unit (5) for rotating the platform assembly so as to control the rate of angular displacement of the platform assembly with respect to an Earth fixed reference frame.