The adsorption and transport behavior of shale gas in nanochannels with three-dimensional random roughness

Understanding the adsorption and transport behavior of shale gas is highly critical for assessing gas-bearing properties of reservoirs and enhancing shale gas recovery. However, the underlying mechanism is still an open question due to the irregularly rough characteristic within nanochannels of reservoirs. In this paper, the migration behavior of shale gas in nanochannels with three-dimensional random roughness is studied by using molecular dynamics simulation and theoretical analysis. It is found that random roughness leads to intense gas adsorption, which contributes to the large reserve phenomenon in engineering practice. In contrast, significant obstruction of shale gas's transportation is observed due to the roughness of the walls. The exploitation of shale gas may be improved by generating channels/fractures with smoother surfaces, increasing pressure gradient, and adopting higher temperature. These results should be of importance in enhancing our knowledge of storage and exploitation of shale gas and guiding the improvement of corresponding technologies in energy engineering.