Geothermal Development Promotion Survey Project in Japan

Abstract

For enhancement of geothermal power development by private sectors in Japan, NEDO (New Energy and Industrial Technology Development Organization) has been performing a program of ìPromotion Survey Projectsî. In the Survey Projects, geoscientific studies and surveysógeological and geochemical studies, a geophysical survey, well-drilling, welltest and reservoir evaluationsóhave been carried out as NEDO projects sponsored by the Japanese government. So far, more than 50 geothermal areas in Japan have been studied using this program. In Japanese geothermal power development, the program of these Survey Projects has been believed effective to encourage private sector development and technology support. Development in the some geothermal fields where the Survey Projects had been applied was continued and construction and operation of power plants were conducted. The survey project program is divided into three kinds of surveys at present, namely Surveys A, B and C. Depending on area and study content, an appropriate survey is applied to the selected geothermal area. In this paper, the project program and the recent survey results are introduced. Positive indications on the potential of geothermal resources have been obtained in the survey projects at Shibetsu-dake, Ashiro, Wasabizawa and Akinomiya. In the Shibetsu-dake area, where the project was conducted as Survey A with relatively large area, regional geological and geothermal structures were clarified using geoscientific data mainly obtained by surface studies and surveys. A high temperature zone (above 260 deg. C) was detected by welldrilling. Geothermal potential in this area is judged to be enough to perform the succeeding detailed survey. Existence of geothermal fluid at depths in the Ashiro area where the project was conductedóas Survey Bówas confirmed by a well-discharge test. Further studies are necessary to realize power generation in the field. In the Wasabizawa area and the Akinomiya area where the projects were conducted as Survey C, geothermal reservoirs of high potential (higher than 270 deg. C), which are enough to be utilized for power generation, were confirmed using several exploratory wells. Near-future construction of power stations in these areas is expected. Besides the above areas, NEDO is carrying out 5 promotion survey projects for finding geothermal resources of high potential simultaneously at present (1999). The activities of NEDO are expected to be useful for the private sectorís geothermal development in Japan.