Molecular simulation of shale gas adsorption in organic matter

Abstract

The CH4 adsorption behavior in organic matter in shale has important significance. We choose organic matter as the research object and construct type I kerogen molecular model to study the adsorption behavior of CH4 using the Monte Carlo and Molecular Dynamic methods. The results show: (1) the adsorption amount of CH4 increases with pressure increases. The adsorption of CH4 is accorded with the law of Langmuir adsorption and is fit by Langmuir equation; (2) temperature has a greater impact on the adsorption of methane, high temperature is not conducive to the adsorption of CH4, at the same equilibrium pressure, the higher the temperature, the smaller the amount of adsorption; (3) radial distribution function indicate there is a strong interaction between kerogen and CH4, different atomic plays a different role for adsorption in kerogen; (4) at low pressures, the adsorption is the main reasons for volumetric strain, and at high pressures, the pressure play a significant role in volumetric strain.