Effect of dielectric continuity of media in immediate proximity to the generator loop on results of near-field transient electromagnetic sounding in the microsecond range
https://doi.org/10.32454/0016-7762-2025-67-1-86-94
EDN: NPDNOR
Abstract
Background. The method of near-field transient electromagnetic sounding (TEM) involves the study of transient fields excited in the earth under the action of changes in the source current. Initially, transient measurements were conducted at times from 100ms and greater; however, in the 1990s, an active study of transient fields in the microsecond range began. Since the microsecond range corresponds to frequencies close to 1 MHz, some parameters of installations, which had been previously neglected, began to attract attention due to their significant contribution to the measured signal. In the 1990s, research was initiated to assess the effect of various installation parameters on measurement results in the microsecond range. At the same time, the effect of the dielectric constant of media in immediate proximity to the generator loop has not been evaluated. Aim. Experimental evaluation of the effect of the dielectric constant of a medium in immediate proximity to the generator loop on the measured transient process. Materials and methods. Field experiments and analysis of the results obtained. Results. The results of measuring transient fields at various parameters of the medium located in immediate proximity to the generator loop are presented. Their analysis is carried out. Conclusion. (1) When working at early (0.1—10 ms) times by the TEM method using an ungrounded current loop as a source, it can be possible to receive signals distorted by processes occurring in the loop itself due to the external parameters of the medium in which the generator loop is located. (2) The shunt resistance should be selected depending on both the size of the generator loop and the effective parameters of the medium in which the generator loop is located.
About the Author
P. V. Novikov
Sergo Ordzhonikidze Russian State University for Geological Prospecting
Russian Federation
Russian Federation
Petr V. Novikov — Cand. Sci. (Tech.), Assoc. Prof., Department of Geophysics
23, Miklukho-Maklaya str., Moscow 117997
References
1. Aladinsky A.Yu., Novikov P.V. Transformation of a transient signal of a coaxial installation of the transient method into apparent electrical conductivity. Izv. universities Geology and exploration. 1990. No. 2. (In Russ.).
2. Barsukov P.O. Pulsed electromagnetic sounding in the microsecond range: Author’s abstract. dis. … Doctor of Physics and Mathematics Sciences. Troitsk, 2004 (In Russ.).
3. Barsukov P.O., Fainberg E.B., Khabensky E.O. TEMFAST-technology for shallow electrical exploration Instruments and systems for exploration geophysics. 2006. No. 2. P. 28 (In Russ.).
4. Bucharsky B.V., Goryachev V.V., Pavlov A.T. Development of a shallow modification of electrical exploration of the ZSB: Izv. universities Geology and exploration. 1986. No. 8. P. 74—79 (In Russ.).
5. Bychkov Yu.A. Zolotnitsky V.M., Chernyshev E.P. Fundamentals of the theory of electrical circuits. St. Petersburg: Lan, 2002 (In Russ.).
6. Kamenetsky F.M., Novikov P.V., Timofeev V.M. The use of differential transformations for the qualitative interpretation of electromagnetic sounding data by the field formation method: Physics of the Earth. 1993. No. 9. P. 91—96 (In Russ.).
7. Kozhevnikov N.O., Plotnikov A.E. Assessing the capabilities of the transient process method in studying the upper part of the geological section Geophysics. 2004. No. 6. P. 33—38 (In Russ.)
8. Kozhevnikov N.O. Transient process in the loop and its use in evaluating a measurement system for pulsed inductive electrical prospecting Geology and Geophysics. 2012. T. 53. No. 11. P. 1614—1627 (In Russ.).
9. Kozhevnikov N.O. The process of turning off the current in an ungrounded loop: what it depends on and how much we can control it Interexpo Geo-Siberia. 2015. T. 2. No. 2. P. 102—106 (In Russ.).
10. Kozhevnikov N.O., Sharlov M.V., Sharlov R.V., Stefanenko S.M., Agafonov Yu.A. Peculiarities of switching off “large” and “small” currents in an ungrounded horizontal loop of Interexpo Geo-Siberia. 2016. T. 2. No. 2. P. 207—211 (In Russ.).
11. Kozhevnikov N.O. Switching off the current in a horizontal ungrounded loop: experiment and theory Geology and Geophysics. 2016. T. 57. No. 3. P. 631—641 (In Russ.).
12. Novikov P.V., Timofeev V.M. Distortions of the early stages of transition processes. Electromagnetic induction in the upper part of the Earth’s crust, Moscow: Nauka, 1990. P. 130—133 (In Russ.).
13. Electrical prospecting. Geophysicist’s Handbook. Moscow: Nedra, 1980. P. 241—246 (In Russ.).
14. TEM-3D-Wizard — 3D Processing of TEM Data. Applied ElectroMagnetic Research (AEMR), the Netherlands. AEMR, 2020.
15. Barsukov P.O., Fainberg E.B. and Khabensky E.O. Shallow investigations by TEM-FAST technique: methodology and examples. In: Electromagnetic Sounding of the Earth’s Interior. Theory, Modelling, Practice. Ed. V.V. Spichak. Amsterdam, 2015. P. 47—78.
16. Fast-Snap TEM measurements. SiogmaGeo, 2020. https://sigma-geo.ru/fastsnap?lang=en
17.
Review
For citations:
Novikov P.V. Effect of dielectric continuity of media in immediate proximity to the generator loop on results of near-field transient electromagnetic sounding in the microsecond range. Proceedings of higher educational establishments. Geology and Exploration. 2025;67(1):86-94. (In Russ.) https://doi.org/10.32454/0016-7762-2025-67-1-86-94. EDN: NPDNOR
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