"Shale Reservoirs as Potential CO₂ Storage Sites: Exploring Mineralogical and Organic Interactions"

Shale reservoirs are recognized for their ability to serve as natural barriers for conventional hydrocarbons and their suitability for CO₂ sequestration, owing to their organic-rich composition and intricate pore structures. This study investigates the shales of the Barakar Formation in the Mand Raigarh Basin, India, to evaluate their potential for CO₂ storage by analyzing factors influencing pore volume and surface area. A comprehensive suite of analytical techniques—XRD analysis, Rock-Eval pyrolysis, and low-pressure gas adsorption using N₂ and CO₂ probes—was employed to assess mineralogy, organic matter content, and pore characteristics. Thermal maturity assessments revealed that the shales are transitioning from immature to marginally mature stages, with kerogen types reflecting a mix of gas-prone and oil-prone organic matter. Mineralogical analysis highlights the predominance of clay minerals, alongside other components influencing shale composition. High-resolution 2D imaging offers a detailed understanding of pore structures, emphasizing the role of organic matter and clay minerals in controlling gas adsorption behaviour. Mesopore development was strongly associated with clay minerals, while organic matter predominantly governed micropore formation. Fractal analysis revealed the complexity of pore morphologies, showing higher irregularity in smaller mesopores than larger ones.  These findings underscore the intricate relationship between mineralogical and organic components in determining the suitability of Barakar Formation shales for CO₂ sequestration. By integrating insights into thermal maturity, organic composition, and pore structure, this study highlights the Barakar Formation shale’s significant potential as a secure and efficient CO₂ storage site, contributing to climate change mitigation, sustainable resource management, and a deeper understanding of shale's role in carbon sequestration. This work contributes to climate change mitigation strategies by leveraging the structural and compositional characteristics of shale formations for carbon management. The results align with global sustainability objectives, transforming shales from traditional energy resources into effective tools for reducing atmospheric CO₂ levels, thereby bridging energy needs with environmental management.