Transport characteristics of shale gas under the interaction of roughness and water saturation in amorphous kerogen nanopores.

This article focuses on the transport characteristics of shale gas, specifically methane, in amorphous organic nanopores composed of kerogen, under the combined effects of surface roughness and water saturation. Using molecular dynamics simulations and a novel construction method based on Gaussian random rough surfaces, the study finds that increasing nanopore roughness significantly reduces methane mass flux, especially at lower roughness levels, and establishes an analytical model quantifying this effect via the Maxwell slip coefficient. It also reveals that water clusters tend to reside in surface pits of rough nanopores at low saturation, altering pore morphology and roughness, while water saturation primarily hinders methane transport by reducing pore volume and disrupting the methane adsorption layer, thereby diminishing surface diffusion contributions. Overall, the research highlights the complex interplay between roughness and water saturation in shaping methane transport mechanisms within kerogen nanopores, with implications for more accurate shale gas production predictions.