Hydraulic Stimulation of Enhanced Geothermal System: A Case Study at Patuha Geothermal Field, Indonesia

초록

This paper discusses a case study on the enhanced geothermal system (EGS), which entails a hydraulic stimulation at Patuha geothermal field, West Java, Indonesia. Patuha field is a volcano-hosted vapor-dominated geothermal system. A hydraulic stimulation was designed with 6,360 m(3) (=40,000 barrels) of water injection to evaluate the enhancement in steam production. The water injection was conducted in three phases: a step-up period, a plateau period with a constant rate, and a step-down period, which raised the bottom hole pressure effectively and positively influenced formation. In addition, in EGS, rapid restorations of pressure and temperature to their pretest values near the bottom hole were observed, unlike in a typical nonvolcanic system. Hall plots, i.e., the Hall integral and Hall derivative, confirmed that the geothermal reservoir was stimulated, and thus, the hydraulic stimulation increased the steam production up to 11.4% at other production wells that were located near the cold-water injector.