Integrated Insights into CO ₂ Storage, Trapping Mechanisms, and Hydrocarbon Recovery in Coal and Shale from the Damodar Valley Basin, India

This study investigates the CO2 storage potential, trapping mechanisms, and hydrocarbon recovery in coal and shale samples from the Damodar Valley Basin, India. Techniques such as proximate and ultimate, petrography, Rock-Eval and total organic carbon (TOC), nitrogen adsorption/desorption, and X-ray diffraction (XRD) and high-pressure CO2 and CH4 adsorption were employed. The results, integrated with stratigraphic and lithological data, provide insights into the burial history, basin structure, thermal maturity, kerogen type, pore characteristics, mineralogical composition, and CO2 trapping mechanisms. The findings revealed thermally mature and carbon-rich coal and shale with TOC ranging from 3.07 to 62.54 wt % and carbon content of 1.85–57.76 wt %. Coal samples are vitrinite-rich (44.65–61.84 vol %), and shale samples are dominated by mineral matter (29.80–62.80 vol %). The presence of type II, III, and IV kerogens supports hydrocarbon generation. The mesoporous nature of samples (2.97–4.23 nm) is conducive to CO2 storage and hydrocarbon extraction. The CO2 adsorption capacities of 16.90–30.30 cm3/g are significantly higher than the CH4 adsorption capacities of 6.20–11.30 cm3/g, favoring the scope for CO2 injection for CH4 displacement. Also, the findings of this study indicate that TOC, moisture, mineral matter, maceral composition, and pore size distribution have a combined influence on the CO2 adsorption capacity. The basin’s geological and reservoir parameters, including depth, temperature, pH, and formation water chemistry, with the reactive mineralogy comprising clays and minerals like kaolinite, Illite, albite, and siderite, collectively help in structural, capillary, solubility, and mineral trapping of CO2. Overall, this study provides a simultaneous evaluation of both coal and shale samples for CO2 storage and hydrocarbon recovery, unlike many prior studies that address them separately, and the findings of this study demonstrate that the Damodar Valley Basin offers a promising potential for CO2 storage, presenting a dual solution for energy resource utilization and greenhouse gas mitigation.