Carbon Dioxide Geological Storage Coupled with Methane Adsorption-Desorption Dynamics from Shale Plays

As rising CO₂ levels accelerate climate change, innovative carbon capture and storage (CCS) solutions are urgently needed. Unconventional shale reservoirs offer a dual advantage: enhancing CH₄ recovery through competitive adsorption while providing a long-term storage medium for CO₂. The nanoporous structure and high organic content of shale formations enable CO₂ sequestration while facilitating CH₄ desorption, thereby increasing gas production. This study develops a numerical simulation framework to model gas flow in shale nanopores, incorporating competitive adsorption-desorption dynamics. A multi-component gas flow model, integrating the extended Langmuir isotherm and the classical Langmuir model, is employed to compare permeability variations and predict CO₂-CH₄ interactions in organic-rich shale formations. The results demonstrate that CO₂ injection enhances CH₄ recovery by displacing methane, with its effectiveness influenced by pressure conditions. The high adsorption affinity of CO₂ ensures its long-term retention within the shale matrix, reinforcing its viability as a storage medium. These findings provide valuable insights into optimizing carbon storage and shale gas recovery strategies. By refining CO₂ injection techniques, this work contributes to advancing sustainable energy extraction while mitigating greenhouse gas emissions, thereby addressing critical challenges in CCS implementation.