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

Abstract 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.