The understanding of gas adsorption and transport behaviors in nanoscaled pores plays a critical role in evaluating unconventional gas exploitation from tight gas reservoirs. In the present work, the transport diffusion mechanisms and behaviors of a CO 2 /CH 4 mixture in shale inorganic and organic nanopores are explored by employing grand canonical Monte Carlo (GCMC) and molecular dynamics (MD) simulations. Kaolinite and kerogen slit nanopores are first constructed to represent the inorganic and organic nanopores of the shale matrix. Then, the effects of temperature, pressure, and pore size on the adsorption and diffusion characteristics of CO 2 /CH 4 are examined. The diffusion trajectories clearly show different diffusion mechanisms for gas molecules near the surface and middle area of the pore. Both surface diffusion and Knudsen diffusion have been observed for CO 2 /CH 4 diffusion in shale nanopores. The surface diffusion of CH 4 has been found weakened with the presence of CO 2 . Simulation results indicate that the conditions of higher temperature and lower pressure are beneficial to the efficiency of CH 4 diffusion. With the increasing pore size, the impact of surface diffusion on gas transport gradually weakens, leading to the stronger diffusion of CH 4 over CO 2 in shale nanopores. The obtained results could provide insights into the diffusion mechanism of CO 2 /CH 4 in shale nanopores and offer fundamental data for CO 2 sequestration with enhanced gas recovery (CS-EGR) in shale reservoirs.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.