CAPABILITIES OF SHALLOW-DEPTH TRANSIENT ELECTROMAGNETIC SOUNDINGS FOR IDENTIFICATION OF GAS-HYDRATE ACCUMULATIONS IN THE CRYOLITHOZONE OF THE NORTHERN REGIONS OF WESTERN SIBERIA
E.V. Murzina1,2, A.V. Pospeev1,3, I.V. Buddo1,3,2, M.V. Sharlov2, I.K. Seminskiy1,2, N.V. Misyurkeeva1,2, I.A. Shelohov1,2
1Institute of the Earth’s Crust, SB RAS, Lermontova str. 128, Irkutsk, 664033, Russia
2LLC SIGMA-GEO, Zvezdinskaya str. 6, Irkutsk, 664039, Russia
3Irkutsk National Research Technical University, Lermontova str. 83, Irkutsk, 664074, Russia
Keywords: permafrost, cryolithozone, gas hydrate, transient electromagnetic method, TEM, induced polarization, resistivity
Abstract
The territory of the north of Western Siberia is known as one of the promising regions of the Russian Arctic in terms of reserves of alternative fuel sources, in particular, gas hydrates. According to the results of interpretation of the data of 3D transient electromagnetic method (TEM) in the cryolithozone, performed in the Nadym district of the Yamalo-Nenets Autonomous Okrug at depths of 100-220 m, geoelectric anomalies of increased electrical resistivity values were revealed, accompanied by the induced polarization anomalies. The authors associate the mentioned anomalies with the possible accumulations of gas hydrates in the cryolithozone. To justify the applicability of the transient electromagnetic method in the near field zone in a shallow modification for mapping subpermafrost geoelectric anomalies in the cryolithozone, a description of a mathematical experiment is presented in the paper. The experiment is based on empirical electromagnetic data. As a result of mathematical modeling, it is shown that the use of transient electromagnetic method makes it possible to estimate the conductivity and polarizability of the upper part of the section of the study area and to identify anomalies in the cryolithozone, which are probably associated with hydrate-bearing deposits.
|
