A Study of the Pressure-Flow Response of the Hijiori Reservoir at the Hijiori HDR Test Site

Abstract

Since 1986, R&D project of Hot Dry Rock (HDR) geothermal energy has been carried out at Hijiori in Yamagata prefecture, Japan. At present, the Hijiori HDR system has two reservoirs (a shallow reservoir and a deep reservoir) and four wells (SKG-2, HDR-1, HDR-2a and HDR-3) as is shown in Figure 1. The Hijiori multi-reservoir system consists of two injection wells in the artificial reservoirs (SKG-2 into the shallow reservoir, HDR-1 into the deep reservoir) and two production wells, HDR-2a and HDR-3, which also intersect the shallow reservoir. Considering a cost performance, multi-reservoir system is important technique for the development of HDR. In order to clarify the behavior of the multi-reservoir system as a first step, we had investigated a pressure-flow relation between SKG-2 and HDR-3 of the shallow reservoir. In this paper, we added the new data between SKG-2 and HDR-3 of the shallow reservoir. Furthermore, we examined the pressureflow relation between SKG-2 and HDR-2 of the shallow reservoir, and compared with the relation of the deep reservoir.