Comprehensive Evaluation of Geothermal Potential at Mount Ciremai Geothermal Field, Indonesia, Using Reservoir Modelling and Uncertainty Quantification Method

Abstract

Evaluating geothermal potential is an essential step in determining the sustainability of a geothermal project, both technically and economically. This study assesses the Mount Ciremai Geothermal Field in Indonesia to determine its feasibility for clean electricity generation through 3D reservoir modelling and numerical simulations. A 3D conceptual model was developed by integrating stratigraphy, lithology, structural alignments, and magneto-telluric data. A numerical simulation was conducted using AUTOUGH2 and the final calibrated model has a total upflow of 56 kg/s with an enthalpy of 1,250 kJ/kg. The model accurately represented surface features, such as the alignment of hot springs. Resource estimation combined with Approximate Bayesian Computation (ABC), iterative algorithms, and numerical modelling, estimated a low P90 power output of 1.1 MWe for 25 years due to the low water table limiting natural discharge. However, by drilling deviated wells from a 500m lower elevation, the estimated resource potential increased significantly to P90/P50/P10 values of 28.6/37.5/55.1 MWe. This study emphasizes the importance of reservoir modelling in the geothermal pre-development phase. It demonstrates that well placement and accurate 3G data integration (hydrogeological, geological, geochemical, and geophysical) are crucial for estimating and optimizing the resource potential within the system. The findings provide valuable insights into geothermal reservoir assessment and highlight how adaptive drilling strategies can significantly improve feasibility.