澄川地熱地域の蒸気熱水二相型貯留層挙動の 数値シミュレーションとそれに及ぼす相対浸透率曲線の影響

抄録

Geothermal wells at Sumikawa are divided into two groups: one produces fluids of vapor dominated and another of water dominated. This is probably because of the presence of vapor-dominated zone formed partly in the reservoir of water single-phase. A numerical three dimensional reservoir model was developed for simulations both natural state and history matching of production and reinjection for about 25 years since the start of the power generation at Sumikawa in 1995. A relative permeability curve of Corey type was employed with residual saturations of 0.23 and 0.16 for water and steam, respectively. Simulation results of specific enthalpy history of produced fluids at Wells SA-1 and SA-3 showed good agreement with measured values in the range of 1500- 2500 kJ/kg. A horizontal narrow layer of high permeability in the model was assigned in the area connecting high temperature zone in the south and the grid where Well SA-1 presents for describing high specific enthalpy values and its gradual decrease with time.