| Abstract |
The Karaha Bodas Geothermal Field, operated by PT. Pertamina Geothermal Energy, is located in the Tasikmalaya and Garut regions of West Java, Indonesia. The geothermal power plant, with a capacity of 30 MWe, began commercial operations in April 2018. In 2023, geochemical monitoring of the surface manifestations identified four distinct complexes: Karaha, Cipanas-Pamoyanan, Talaga Bodas, and Pancur Tujuh. Each complex has a unique water chemistry: sulphate-type waters dominate in Karaha and Talaga Bodas, bicarbonate-type waters in Cipanas-Pamoyanan, and chloride-rich waters in Pancur Tujuh, where the high chloride levels are linked to magmatic fluids. Recent monitoring has shown rising temperatures and chloride levels in Pancur Tujuh, accompanied by a decrease in magnesium, indicating extensive reservoir boiling. This phenomenon is further supported by an increase in non-condensable gas (NCG) content in the fumaroles of Talaga Bodas. Additionally, extensive boiling has been observed in the production wells, attributed to the non-return of reinjected fluids. To address these challenges, an injection strategy is currently being tested in the Karaha Bodas field to improve reservoir management. |