Challenges in Well Testing Initiatives in Dieng-2 Geothermal Expansion Project, Central Java, Indonesia

Abstract

PT Geo Dipa Energi GDE (Persero) has embarked on the expansion of Dieng Geothermal Field in Central Java, Indonesia in November 2021 based on the updated resource assessment and reservoir modelling of greater Dieng resource, follow on geoscientific studies and feasibility update of Dieng project. The expansion program called for drilling of five (5) production wells and five (5) injection wells to support the 55 MWe Dieng-2 power plant. The drilling campaign was successfully completed in July 2023, but the programmed production well testing activities encountered a good number of challenges that presented difficulties in proving the capacity of the wells to confirm the power plant infrastructure development. This paper details the challenges involved in confirming the production capacities of Dieng-2 wells namely a) meeting the prescribed environmental, safety and social standards related to H2S gas emissions, brine carryover, noise levels and vibration that could potentially affect the nearby households, b) discharge fluids highly supersaturated with common minerals (e.g., silica), and c) production casing damage from unprogrammed mechanical workover. GDE has designed several work initiatives to mitigate and address the above challenges and considered some novel solutions which are elucidated in this paper.