Home – Home – Jornals – Russian Geology and Geophysics 2019 number 4

Theoretical studies and methodical recommendations in pulsed electrical prospecting are based mainly on the technique of pulsed excitation with an instantaneous turn-off of direct current. In practice, the duration of current passage is determined by the depth of sounding and by economic and time expenditures. The pulse duration affects the late stage of the electromagnetic-field transient. At the early stage, it also depends on the turn-off front, which cannot be too short for technical reasons. On the solution of the direct problem, it is necessary to take into account the real parameters of the current pulse. Earlier it was proposed to use a special current pulse waveform to optimize sounding (the compensation transient electromagnetic method was implemented). We propose to look at the problem more broadly, in terms of separation of the nonstationary geoelectromagnetic field into TE and TM polarizations, which are excited by different sources. It turns out that the dependence of these polarizations on the waveform of the exciting pulse can be radically different in media with an insulating base.