Borehole logging using magnetic fields

摘要

In a borehold logging instrument two coils are rotated by a synchronous motor. The first coil rotates within a gimbal mounted Helmholtz coil whereby intersection of flux fields generates a signal representative of the degree of borehole inclination. A second, or compass coil rotating with the first co-operates with the Earth's magnetic field to produce a signal representative of the azimuth direction of the borehole deviation.