Application of Time-frequency Electromagnetic Method in the Exploration of Deep Geothermal Resources

Abstract

With “deep into the earth” proposed，the exploration of deep geothermal resources has become the forefront of geothermal resource exploration. As an important part of deep geothermal resource exploration, geophysical survey has the technical characteristics of greater exploration depth, higher precision and efficiency of exploration, lower exploration cost and so on. At present, due to the increasing depth of geothermal exploration and the constantly improved detection accuracy, the detection effect of ordinary electromagnetic method is obviously insufficient. Time-frequency electromagnetic method (TFEM) is widely used in petroleum, shale gas, coalfield and other exploration areas with its advantages of stronger anti-interference capability, greater exploration depth, combined time and frequency domain analysis, and obtained a variety of electrical parameters. Based on the exploration of deep geothermal resources in the dongli lake area of Tianjin, TFEM has been used for the first time in the sedimentary basin of the north China plain. The result shows that TFEM can extract the real earth’s electromagnetic information under the condition of strong background noise, achieve effective exploration depth of 5 km, furthermore, divide stratigraphic structure and determine the fault location accurately combined with seismic, well logging, drilling data and other geologic information.