| Abstract |
Heat extraction from HDR geothermal resources in Japan has been carried out in several circulation tests under experimental development programs supported by the Japanese government and the electric utilities of Japan. Two major HDR resources under current investigation are the Hijiori HDR reservoir (by NEDO) and the Ogachi HDR reservoir (by CRIEPI) both in the northern Honshu region of Japan. Several circulation tests of one to several months have been conducted in each resource to obtain reservoir flow characteristics necessary for planning long-term production tests in later phases of the two programs. For optimum thermal analysis of the resources, expectations of energy extraction behavior is needed to evaluate the resources for commercial energy mining operations. Several aspects of the two resources, such as geologic structure and total resource size and heat content as defined by the temperature distribution in relation to the reservoir stimulation geometry needs further analysis. To assist in evaluating the thermal extraction aspects of the tests, comparison of modeling forecasts with measured test data were carried out. Heat extraction calculations with the Stanford Geothermal Program heat-sweep model, based on radial sector flow estimation, were made for the several circulation tests during the 1990s. The resulting calculations of thermal energy extraction from the test segments were accumulated to evaluate long-term expectations for each resource. Analysis of the combined data for the two somewhat differently stimulated HDR resources should be of value in evaluation of the northern Honshu region of Japan a s a long-term useful source of HDR geothermal-energy-derived electric power. |