Updated Conceptual Model and Resource Assessment using Numerical Reservoir Simulation of Danau Ranau Geothermal Field Indonesia

Abstract

Danau Ranau geothermal field is located in Lampung and South Sumatra province, Indonesia. It is classified as a high terrain volcanic hydrothermal system controlled by the Sumatran fault as the permeability zone. The study aims to characterize the Danau Ranau reservoir, update the conceptual model, and assess the geothermal power capacity coupled with Monte Carlo simulation. Therefore, the numerical reservoir simulation is performed using TOUGH2 software to achieve a natural state model based on geoscience interpretation data. The numerical reservoir models' output matches the geological, geochemical, and geophysical interpretation, thus becoming important information (3D pressure and temperature, heat and mass flow, location of heat source, boundary condition, reservoir geometry) in the updated conceptual model. The probabilistic heat stored method results based on the natural state model's output show that Danau Ranau geothermal field can generate up to 30 MW.