Geological exploration - in boreholes using electrical sounding

摘要

In electrical underground prospecting by emitting a low frequency current between two adjacent points in the ground, measuring an electrical potential difference induced by this current between two other points spaced from the first to permit evaluation of one of the parameters rho e (electrical resistivity) and mu e (the equiv. magnetic permitivity), knowing the other from the values of the assembly of strata sepg. the current emission position from the position of the potential difference measurement, a novel feature of this technique is that the value of the parameter is determined by comparison with the measured value for potential difference to the value V calc. defined by where e1 = mean local resistivity near the wall of the bore hole of the stratum sepg. the two points for which the potential difference is measured: I = emitted current intensity in the ground gamma e = (e + j) square root w mu 2/2 rho e: w = 2 pi f: D24, D25, D34, D35 = distances sepg. each of the two emission points from each of the two points between which the potential difference is measured.