EVALUATING THE EFFICACY OF 3D MODELING IN ELECTRICAL RESISTIVITY TOMOGRAPHY: A CASE STUDY FROM THE GORLOVSKAYA DEPRESSION
N.N. Nevedrova1, Z.Y. Kuzina1, A.M. Sanchaa1, E.V. Balkov1
1Trofimuk Institute of Petroleum Geology and Geophysics, Siberian Branch of the Russian Academy of Sciences, Novosibirsk, Russia
Keywords: Electrical tomography, numerical modeling, three-dimensional inversion, data verification, quantitative analysis
Abstract
The article presents a methodology for quantitative verification of three-dimensional geoelectric models constructed from electrical tomography (ET) data in complex geological conditions. As an example of real data, a set of measurements is considered in the fault zone of the southeastern boundary of the Gorlovka depression (Novosibirsk region), where an increase in seismic activity has been observed in recent years. It is probably caused by the development of large coal mines. The relevance of the work is due to the interpretative ambiguity of ET data in heterogeneous geological environments and the appearance of artifacts in inversion models, which can subsequently lead to false interpretation of the results. It is proposed to move from the traditional visual comparison of the results of inversion of field and synthetic data to quantitative analysis. For this purpose, the ERT_Comp software tool has been developed, which calculates the relative difference between the model and field values of apparent resistivity at specific spacings. The use of the technique for field data from three parallel profiles made it possible to quantitatively substantiate the choice of the optimal 3D geoelectric model reflecting the presence of a subvertical fault zone. The proposed approach does not completely remove ambiguity, but significantly increases the reliability of interpretation. Prospects for the work involve the use of gradient models and the establishment of standardized threshold values of relative deviations to select the best interpretive model.
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