ELECTRICAL PROSPECTING METHOD FOR STUDYING THREE-DIMENSIONAL GEOLOGICAL STRUCTURES

摘要

The invention relates to geo-electrical prospecting and can be used for conducting searches for geological features, in particular hydrocarbon deposits, ore bodies and kimberlite bodies, using transient electromagnetic methods, and can also be used in a frequency mode. The present method includes forming an electromagnetic field source. For this purpose, eight horizontal radial grounded lines which converge to a centre are laid at equal angular intervals, wherein the radius corresponds to the exploration depth, and the lines are grounded by a central electrode. A pulsed current is supplied to each horizontal radial grounded line of the thus formed electromagnetic field source. An alternating electromagnetic field having transverse magnetic polarization is identified. The electromagnetic transient response signal of the medium under investigation is measured. The pulsed current is supplied to the horizontal radial grounded lines one at a time. The value of the actual current of a horizontal radial grounded line is recorded. In the response from the medium under investigation, the share of the alternating electromagnetic field having transverse magnetic (TM) polarization is identified by summing the responses normalized to the actual current when the medium is excited by each of the eight horizontal radial grounded lines. The invention makes it possible to radically simplify the technical formation of a source of a TM-polarized electromagnetic field and to expand the potential for the use thereof, thus significantly increasing the efficiency of electromagnetic exploration of the Earth when detecting weak lateral heterogeneities (for example, of the petroleum deposit variety).