Simulation of CO2 enhanced coalbed methane recovery in Jharia coalfields, India

Coalbed methane production in Jharia coalfield that lies in India's largest coal basin is underway since a few years now; however, no field-trial of CO2 enhanced coalbed methane (ECBM) recovery has been attempted till date. In this study, a detailed assessment of the techno-feasibility of long-term ECBM recovery for a coal block in Jharia coalfield was conducted using finite difference based numerical simulations. This was followed by a detailed comparative analysis with the performance of another key CBM producing block in Raniganj coal field (Vishal et al. [1]). During coupled CO2‒ECBM recovery, a significant enhancement in the amount of production of CH4 resulted due to the injection of CO2. Approximately, 220 Mm3 of CO2 was injected in the coal block and over 62 Mm3 of CH4 was recovered during the period of study. Upon comparison of the studied coal blocks, it can be well inferred that during the major dewatering stage, the rate of CO2 injection in Jharia block was lower as compared to that in the Raniganj coal block. The studied coal adsorb CO2 quickly and within a time span of nearly one year, peak CO2 matrix concentration near the injection well was achieved, indicating high adsorption potential for CO2.