The data acquired from geoscientific survey (i.e. geophysics, geology, and geochemistry), supported by exploration well data, is evaluated and then simulated to predict potential reserves and time limits of steam in a geothermal field can be generated.

Reservoir modelling and simulation give a comprehensive approach for understanding geothermal reservoir in order to predict its future performance under different development and production strategies. There are several concerns in reservoir modelling and simulation, covering:
• Numerical Simulation
Simulation is used to determine natural state (initial state) condition since geothermal reservoir is a dynamic process even before starting the exploitation.
• History Matching
Process of reservoir parameter adjustment that imposed historical data to the model for production simulation, including: production rate, injection rate (brine, condensate), enthalpy of injected brine and condensate
• Production Forecasting
Using a calibrated numerical model to calculate number of make up wells to sustain steam extraction, forcasted generation profile and production decline rate in order to make better strategic resource recovery decisions and determine the economic value of reservoir.