Application of Comprehensive Geophysical Methods to the Geothermal Field Investigation

Abstract

Two case histories have been briefly reviewed to present the application of comprehensive geophysical to geothermal field investigation. One example from the delineation of the geothermal field in a basalt zone by the AMT method with the one-meter hole temperature measurement; the other is about the exploration of the geothermal water in a sediment strata area using the CSAMT method with the interpretation of seismic data. All examples show that the effective usage of geophysical methods or combination is the key to success in geothermal field exploration. In addition, we introduce three methods in the test of geothermal exploration: gravity imaging, high power CSMT and broadband MT. It proves difficult to geothermal geologists and engineers for few direct ground information could be used to concept the geothermal model. Research has indicated that the geothermal reservoir characterizes as relative low density, higher linear gravity gradient, low resistivity and seismic anomaly. These provide possibility to use indirect information acquired by non-invasion methods. Comprehensive geophysics is such a way to illustrate the pattern of geothermal reservoir by measuring and analyzing the geophysics data which carried the information from media subsurface.