| 摘要 |
The invention relates to the field of geo-physical industrial studies of wells by method of electric logging by resistance. Method for focusing electric current and for measurement of resistance of rocks includes application of same direct current potentials to measuring and screen electrodes and following current passing through screen and measuring electrodes by means of power source of screen electrode and measurement of rock resistance through measurement of potentials of screen and measurement electrodes at instance of condition of current focusing holding true. Process of current focusing and measurement of potentials of screen and measuring electrodes is performed through first and second operation amplifiers connected in differential circuit, and coefficient of amplification of each of those is equal to one, switch K1 by means of which disconnection of circuit of screen electrode is possible, and switch K2 at connection of which to circuit of measuring electrode test resistance with known value is added, at that measurement of voltage for measuring and screen electrodes is performed in 4 stages: at first - at switched power source of screen electrode and disconnected switches K1 and K2, after that one switches on power source of screen electrode and performs measurement at second stage - at closed switch K1 and disconnected switch K2, at third - at closed switches K1 and K2, at fourth - at disconnected switches K1 and K2, after that one calibrates operation amplifiers, performs compensation of errors due to inaccuracy of operation amplifiers and effect of increased temperatures through measurement of voltage difference at screen and measuring electrodes by means of third operation amplifier with inputs connected to screen and measuring electrodes, one determines current through rock on the basis of respective measurements of voltage on measuring and screen electrodes and determines equivalent resistance of rock stratum. Technical result is in increase of level of signals of screen and measuring electrodes and compensation of temperature effect, this leads to increase of reliability of measurements.
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