Mixing Models of Ulubelu Geothermal Field

Abstract

One of Indonesia's most developed geothermal areas is Ulubelu. Its production capacity has increased to 220 MW by a decade of operation. To determine the primary fluid and the procedures it goes through to surface, we look at the mixing model's properties in this study. The fluid flow pattern flows from north to southwest according to the chloride-boron ratio. The parent fluid is known as the reservoir fluid, and the surface-appearing reservoir fluid is known as the WPTM manifestation fluid due to its presence on the chloride apex. The correlation of water isotopes and chloride-boron provides evidence that the parent fluid and the WPTM manifestation fluid come from the same source according to the enthalpy-silica mixing model. From the chloride-enthalpy mixing model we determine the processes that the parent fluid undergoes as it rises to the surface. There are two possible scenarios for this to happen. The first scenario is that there is conductive cooling, then equilibrium on the surface and mixing with the surface fluid seems more plausible. However, we are challenged to prove the second scenario if we can obtain reservoir data in the GTTM area.