METHOD FOR INDUCTIVE VERTICAL SOUNDING Russian patent published in 2000 - IPC

FIELD: electric reconnaissance. SUBSTANCE: method may be used for vertical sounding, when medium parameters should be detected at height greater than 50 m. Method is particularly effective in cases, when horizons of geological section under investigation are covered by layer with high conductance. Method involves double loop excitation of primary magnetic field and measurement of imaginary constituent of vertical component of magnetic field in center of loops. Double loop excitation provides possibility to achieve vertical focusing of primary field at given depth, thus decreasing shielding influence of upper conducting layers. Space symmetry of measuring equipment decreases influence of horizontal heterogeneities. Invention claims excitation of alternating vertical magnetic fields using opposite-phase currents in two coaxial frames, in center of which real constituent of magnetic field is compensated by means of alteration of current ratio in frames. Imaginary constituent of magnetic field is measured in center of frames. Operation is repeated for several frequencies in order to measure parameters of geological section according to frequency response of imaginary resistance. EFFECT: decreased influence of horizontal heterogeneities and upper levels of medium onto results of inductive sounding. 2 dwg