| Abstract |
For geothermal reservoir exploration, the New Energy and Industrial Technolorn Development Organization (NEDO) in Japan has been developing such seismic methods as cross-well tomography, VSP and reflection. For the first two methods, which require wells for measurement, NEDO has developed a new threecomponent, multi-level downhole receiver which is able to operate under temperatures of up to 260?C (500' F). All three methods have been experimentally used to evaluate the geological characteristics of fiacture-type reservoirs at four geothermal fields possessing different types of fiactures and geological structure. As a result of the experiments using these methods, NEDO has obtained accurate seismic images which delineate subsurface structure in volcanic terrain in Japan. |