DEVICE FOR ELECTROMAGNETIC WELL LOGGING PROBING Russian patent published in 1997 - IPC

FIELD: measurement of earth field characteristics; measurement of electric properties of rock in wells drilled for prospecting of petroleum and gas. SUBSTANCE: device has probes similar in geometric and electrodynamic properties. Probes include interconnected generator and sensing coils, multiplexer of generator circuits, power amplifiers, amplifiers-converters, local oscillator, commutator, automatic control unit, and telemetering system. In addition, device has reference-voltage generator, well polarization electrode, well polarization signal converter, and electromagnetic filter. Local oscillator is made retunable, and commutator is essentially multiplexer of measuring circuits. Phase meter is a wide-band device. Multiplexer of generator circuits is connected by means of actuating lines between output of automatic control unit and inputs of power amplifiers. Output of retunable local oscillator is connected to inputs of amplifiers-converters. Well polarization electrode is coupled to input of well Polarization signal converter the output of which is connected to input of telemetering system. Output of reference-voltage generator is connected to input of automatic control unit the outputs of which are connected to inputs of retunable local oscillator, wide-band phase meter, and telemetering system. Electromagnetic filter is positioned between generator coils and sensing coils. Amplifiers-converters and multiplexer of measuring circuits are mounted between electromagnetic filter and sensing coils. number K of coils is within 3 to 2n where n is number of generator coils, and electromagnetic similarity factor is in range of (0.5-15) 10⁶ Hz.sq.m. EFFECT: higher accuracy of measurements. 1 dwg