摘要 |
A method of well logging in petroleum exploration and apparatus for use in the method as described. An improved magnetometer is disposed in a well bore to provide indications of the distribution, filimentation, and distortion of a controlled current flow within adjoining strata of interest. The current flow is excited by a distant alternating source located at the surface or at other boreholes, and perturbations in the current flow and accompanying magnetic field caused by the electrical characteristics of the adjoining strata are registered by the magnetometer. The magnetometer comprises a pair of elongated U-shaped cores of laminated, high-permeability metal, with portions of each core being surrounded by a sensing coil. The coil output is fed to surface equipment for detection and analysis.
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