Numerical study for effect of injection parameters on reservoir: A case study for Lahendong, Indonesia

Abstract

A single-flash cycle of thermodynamic model coupled with a reservoir of numerical model has been developed through the COMSOL Livelink module to investigate the impact of the geofluid mass flow rate and injection temperature on production temperature and net output power of the power cycle. The geothermal reservoir model was established by using a thermal–hydraulic–mechanical (THM) module in COMSOL Multiphysics. Moreover, the single-flash cycle of the thermodynamics model was constructed in MATLAB. The geothermal reservoir conditions of Lahendong, North Sulawesi, Indonesia was adopted to simulate the geothermal power plants’ actual operation. The results revealed that the variation in geofluid mass flow rate and injection temperature impacted production temperature and net output power. The production temperature considerably decreased with an increase in the geofluid mass flow rate. However, the difference in production temperature between geofluid mass flow rates of 50 kg/s and 250 kg/s at 1st and 30th years were 0.23 K and 0.41 K, respectively. The net output power differences were also 16.204 MW and 15.349 MW, respectively. Finally, increasing the injection temperature correspondingly led to an increase in production temperature and net output power, even though the increment did not exceed 1 K and 0.002 MW, respectively.