Geothermal exploration in difficult areas

According to the "Sunshine Project", various geophysical survey have been conducted in many geothermal areas in Japan. In this Project, geophysical data has been interpreted as layered earth structures. However, there are often inherent difficulties in determining layer thickness and resistivities from one geophysical method alone in difficult areas. In order to combat this problem, numerical modeling for 2D or 3D models are usually conducted and the observed data has been carefully checked in order to get the best fitted model in a geothermal area. In the present paper, procedures for interpretation of geophysical data are carefully checked with well log data and an optimum method for geothermal exploration are derived in difficult area from the success case history of Hatchobaru geothermal field ( 55 MW, unit II ) by KEPCO in Japan.