THM Analysis for Assessing Geothermal Energy Production from the Burning Jharia Coal Field, India

ABSTRACT: Most of the world's geothermal energy research is focused on studying various aspects of geothermal doublet technology. In the Jharia coal field (JCF) of India, temperature logs indicated a distinctly high local geothermal gradient, between 5.0 and 5.5°C per 100 meters. This locally high geothermal gradient highlighted the impact of underlying coal fires reflecting significant temperature anomalies across various strata in the basin. The present work is undertaken to determine the feasibility of a geothermal doublet in the JCF basin. The study aims to simulate the THM (thermo-hydraulic-mechanical) processes in the extraction of geothermal energy from the Jharia basin. The effect of coupled variant simulations, operating parameters (injection rate, well location, well spacing) and reservoir rock formations on geothermal heat extraction were investigated to maximize the thermal energy production along with well stability. The results highlighted the impact of injection rates (300-450 m3/hr) on production temperature, obtaining 400 m3/hr as the optimal flow rate for extraction in the studied geothermal doublet. The study showed that placing producer wells in zones with higher reservoir temperatures led to increased production over a five-year time period. The simulation output may enable the design of a pilot geothermal doublet for waste heat recovery process in the JCF basin.