METHOD OF WELL ELECTRICAL RESEARCH Russian patent published in 2002 - IPC

FIELD: geophysical survey of wells. SUBSTANCE: used for the purpose are three gradient sondes of different lengths. Long and medium-long gradient sondes are installed so that their current electrodes are located in common point. Short gradient sonde is located relative to long gradient sonde so that their corresponding measuring sondes in lower point of measurement of long gradient sonde are found at same level. Measuring electrodes of all three gradient sondes are sued for measurement of density of currents at different distances from common pint. These values are used in reduced state with consideration of difference of distances between measuring electrodes. In addition, based on value of current density of long gradient sonde in reduced state is determination of value of current density with consideration of change of current density of section between points of location of its measuring electrodes. Then, obtained values of current density in point of measurement of long and medium-long gradient sondes are used for determination of ratio of value of current leakage into rocks between points of measurement of long and medium-long gradient sondes to value of current directed into well below location of long gradient sonde. This ratio is proportional to ratio of conduction values of rocks and well which are converted into ratio of resistances. Judgment on rock electrical resistance which is converted into resistivity with consideration of coefficient of cylindrical sonde is made by change of ratio of resistances at constant resistance of well. EFFECT: more accurate values of rock resistance due to consideration of possible disturbance of uniform distribution of current. 3 cl, 3 dwg