Theoretical Evaluation of Hot Water Reinjection into Water-Dominated Geothermal Reservoirs

Abstract

Reinjection of hot water is carried out in most geothermal power plants in Japan. The evaluation of the reinjection is important because the reinjection affects geothermal reservoir performance during heat extraction. Many studies have been made on this subject by considering the rock mass in a geothermal reservoir as a homogeneous porous medium. In this paper, a geothermal reservoir is modeled as a finite permeable medium including large natural fractures connecting production and reinjection wells. The analysis is applied to the Takinoue geothermal area in Japan, and the evaluation of reservoir volume and the variation of production fluid temperature are discussed.