Molecular simulations of the adsorption of shale gas in organic pores

Based on the experimental characterisation, carbon slit nanopores were modelled to describe the micro-structure of organic materials within shale. Grand canonical Monte Carlo simulations were performed to simulate the adsorption of methane in slit pores. Adsorption isotherms and density profiles were obtained for a wide range of slit size and pressure. The results showed that the pores in the size of 1–50 nm are dominant places of adsorption in shale reservoir. Under high pressure, multilayer adsorption is prevailing owing to the intermolecular potential. Moreover, as the temperature increases, the adsorption-phase gas decreases, which is attributable to that the motion of gas molecules is more intense at high temperature. This paper presents an effective method to study the adsorption of shale gas, and helps improve the understanding of the adsorption mechanism of shale gas at an atomic level.