Gyroscopic method of testing alignment of a borehole - wherein a boring pipe instrumentation case signals azimuth and inclination

摘要

A device for determining the azimuth and any deviation from the vertical in a borehole or pit includes a gyroscope which puts out a signal varying with its orientation relative to the earth's axis of rotation. The dimensions of the gyroscope are such that it can be assembled with other instruments in a case and lowered down the bore. It comprises a rotor and is supported by a motor which rotates the case and the rotor frame on an axis. A clinometer is also supported and turned by the motor so as to generate signals corresponding to its rotation and the degree of inclination of the instruments' axis to the vertical. A circuit comprising amplifiers and a multiplexer circuit processes the signals at predetermined depths for a recorder. Accurate readings of both deviations from the azimuth and from the vertical are obtained without the inconvenience and expense of repeated withdrawal of boring bars and measuring equipment.