Molecular Simulation of Methane Adsorption in Deep Shale Nanopores: Effect of Rock Constituents and Water

The molecular models of nanopores for major rock constituents in deep shale were constructed. microscopic adsorption behavior methane was simulated by coupling the grand canonical Monte Carlo and Molecular Dynamics methods effect discussed. Based on illite kerogen nanopore models, discrepancies water distribution characteristics elucidated, effects its underlying mechanisms revealed, competitive between elaborated. results show a similar trend different constituents. Illite slit pores have no significant difference capacity. capacity per unit mass is greater than that due to smaller molar skeleton large intermolecular porosity. has affinity methane. With increasing content, molecules preferentially occupy high-energy sites then overspread entire pore walls form layers. Methane are adsorbed layers, little adsorption. Kerogen characterized as mix-wetting. Water polar functional groups gather around clusters. In with high can facilitate cluster fusion suppress spreading along walls. addition adsorption, some dissolve matrix.