Hydraulic Fracturing Tests to Make Geothermal Reservoir for Hot Dry Rock Development at Hijiori Field, Japan

Abstract

Hydraulic fracturing tests were conducted in an existing well to create a fracture near the bottom of the well as one step of hot dry rock development project. The test results showed that a desirable fracture was created by injecting 1,080 m3 of water and 35% of the injected fluid was vented with the maximum temperature of 105°C after injecting. The well, SKG-2 is located in Hijiori, Yamagat Pref., Japan with the depth of 1,802 m and bottomhole temperature of 254°C which was drilled for hydrothermal reservoir exploration by a private company. Through the hydraulic fracturing operation, flow rate, pressure and temperature were recorded as well as micro seismic were monitored both by a triaxial geophone tool and a surface network. Depending on the analysis of data obtained, we have created the fracture large enough for the farther development of hot dry rock research programs.