| 摘要 |
S P E C I F I C A T I O N "Improvements in or Relating to Instruments for Monitoring the Direction of a Borehole" An instrument for monitoring the direction of a borehole comprises an elongate casing having its longitudinal axis coincident, in use, with the axis of the borehole, an outer gimbal pivotally mounted within the casing with its pivot axis coincident with the longitudinal axis of the casing, a gyroscope unit mounted in the outer gimbal, a torque motor and a gravity sensor unit. At the beginning of a run the instrument is positioned at the mouth of the borehole. The rate of rotation about an axis transverse to the outer gimbal axis is then sensed by the gyroscope unit, and the outer gimbal is slewed by the torque motor in dependence on the sensed rate so as to align the transverse axis along an East/West direction. The instrument is then moved along the borehole and the rate of rotation about the outer gimbal axis is continually sensed by the gyroscope unit, the outer gimbal being torqued by the motor in dependence on the sensed rate to stabilize the outer gimbal about its axis. Simultaneously the components of gravity are sensed by the gravity sensor unit. The resulting measurements are used to determine the inclination and azimuth at a plurality of points along the length of the borehole. |
