GEOTHERMAL REINJECTION EXPERIENCE IN JAPAN

The five liquid-dominated geothermal fields under production in Japan (Otake, Onuma, Onikobe, Hatchobaru, and Kakkonda) represent more than half the liquid-dominated fields now in production worldwide. All five have total liquid reinjection programs, and thus collectively represent a major fraction of all full-scale water reinjection operations in the world. The implications of the Japanese reinjection experience are therefore of extreme importance to future liquid-dominated geothermal development. The major impact of the experience in these fields is that, with the exception of Otake, the reinjection wells show a rapid interference with the production wells. In most cases, the reinjected water travels to the production zone within a very short time, and there is consequently a discernible thermal drawdown.