EVALUATION OF SUSTAINABLE PRODUCTION UNDER SINGLE-FLASH AND COMBINED CYCLE POWER PLANT USING NUMERICAL SIMULATION FOR A WATERDOMINATED GEOTHERMAL FIELD

• Main Author: Ridwan Hamdani, Muhamad
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/43865
• Institution: Institut Teknologi Bandung

The reserves and characteristic of the geothermal reservoir should be studied in an integrated and comprehensive manner as reservoir capability is one of the key factors. The aims to reduce the risk of geothermal resources during exploitation. Therefore, the research on evaluating reservoir capability under two energy conversion cycle, conventional and combined cycle, is interesting. In order to answer this challenge, an integrated method between reservoir numerical simulation, wellbore modeling, and thermodynamic analysis for conversion cycles were built, thus producing tools for sustainable resource development. Lumut Balai geothermal field, which is liquid-dominated system and has greenfield status, was chosen as the object of this research. Reservoir numerical model of this field was built using TOUGH2 EOS1 simulator and calibrated using observation data from 18 wells at the natural state stage, and two wells at production data matching stage. The deviation of temperature and pressure from model against the observation data ranges from 1.98 – 11.45oC and 0.5 – 12.42 bar, respectively. This calibrated model is used as the basis to calculate reserves and simulate sustainable production using AUTOUGH2 simulator. The calculation using response surface method Box- Behnken 2nd Order combined with Monte Carlo simulation, produce 52 MWe for most likely value. Simulation results show that both conversion cycles, single-flash, and combined cycle, are capable to produce 55 MWe for 30 years with the same production-injection strategy. The decline of pressure and temperature for these two conversions cycle relatively has the same value, up to 11.2 bar and 8.2oC, respectively, with the same 6 injection wells. The use of both cycles can sustain the production for 30 years, and the combined cycle provides an additional power of 7.2 MWe without causing cooling in the reservoir.