Marginal Recharge Identification Based on Tritium in Darajat and Salak Geothermal Fields

Abstract

Marginal recharge (MR) presents in the peripheral of a geothermal field to support the sustainability of the natural state of the system. There are several types of MR that determined by their sources, namely groundwater, steamheated water, old condensate, and etc. The influx rate of these liquids into reservoir can be accelerated as the mass extraction is begun. The presence of these liquids near the wellbore has been identified to be responsible on several bad impacts at the production wells, such as decrease in temperature, deposition of scale minerals, and decline in production. Since these liquids are very distinct in chemistry and temperature as compared with reservoir liquid, thus geochemistry surveillance program is designed to monitor the penetration of these liquids into reservoir. In Darajat and Salak geothermal fields, tritium (3H) has been collected to investigate the type and distribution of MR. The result of the study in both fields shows that each field demonstrate its own characteristic of MR.