TRANSIENT ELECTROMAGNETIC MONITORING OF THE CRYOLITHOZONE WITH INDUCTION COILS AND A CURRENT LINE: COMPARATIVE STUDY
O.V. Nechaev1, I.V. Mikhaylov1,2, M.N. Nikitenko1, V.N. Glinskikh1,2
1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
2Novosibirsk State University, Novosibirsk, Russia
Keywords: Transient sounding, electromagnetic monitoring, cryolithozone, geoelectric model, numerical simulation, vector finite-element method, Sumudu transform, induction coil, current line, cross-borehole exploration
Abstract
The article considers the results of mathematical modeling of transient electromagnetic cross-borehole monitoring data for civil and industrial cryolithozone facilities containing thaw zones (taliks) in their vicinity. A solution to the direct problem is presented based on the Sumudu integral transform and the vector finite-element method for two types of borehole sources: induction coils and a less common electric current line, taking into account the frequency dispersion of the electrical conductivity of permafrost. Three-dimensional numerical modeling of the transient signals is performed in realistic geoelectric models of a gas-producing borehole and a residential building on piles. Based on the modeling results, we have revealed the main features and differences of transient cross-borehole monitoring with coils or a line as the source.
|
