Geothermal exploration using numerical simulation and a comprehensive electromagnetic method

Abstract

Geothermal resources are a type of important renewable clean energy with high development and usage potential. However, at the same time, geothermal resources are buried deep below the Earth’s surface, they involve significant exploiting hazards. Geophysical methods are frequently required to determine the depth and location of geothermal resources. Among geophysical methods, transient electromagnetic method (TEM) and controlled source audio-frequency magnetotellurics (CSAMT) have comparably high effectiveness and accuracy. This article first introduces the algorithm theory of the finite volume method, then establishes a simplified geothermal system resistivity model. Next, based on this model, simulation analyses of the abilities of CSAMT and TEM were performed to distinguish target faults with different resistivities, dip angles and widths. Finally, combined with theoretical analysis, taking a comprehensive electromagnetic exploration of CSAMT and TEM in Huairen County, Shanxi Province, China as an example, the effectiveness of these two methods in exploring typical geothermal resources is verified. It is shown that both methods can reflect the geoelectric structure from different perspectives, and the efficacy in geothermal exploration using comprehensive electromagnetic method is demonstrated.