Effects of π–π Stacking on Shale Gas Adsorption and Transport in Nanopores

Abstract

The π–π interaction is a prevalent driving force in the formation of various organic porous media, including the shale matrix. The configuration of π–π stacking in the shale matrix significantly influences the properties of shale gas and plays a crucial role in understanding and exploiting gas resources. In this research, we investigate the impact of different π–π stacking configurations on the adsorption and transport of shale gas within the nanopores of the shale matrix. To achieve this, we construct kerogen nanopores using π–π stacked columns with varying stacking configurations, such as offset/parallel stacking types and different orientations of the stacked columns. Through molecular dynamics simulations, we examined the adsorption and transport of methane within these nanopores. Our findings reveal that methane exhibits stronger adsorption in smoother nanopores, with this adsorption remaining unaffected by the nanoflow. We observe a heterogeneous distribution of the 2D adsorption free energy, which correlates with the specific π–π stacking configurations. Additionally, we introduce the concept of “directional roughness” to describe the surface characteristics, finding that the nanoflow flux increases as the roughness decreases. This research contributes to the understanding of shale gas behavior in the shale matrix and provides insights into nanoflow properties in other porous materials containing π–π stackings.

Shale Gas Nanofluid in the Curved Carbon Nanotube: A Molecular Dynamics Simulation Study

“… 68 The flow velocity in CNT is more than 10 times larger than the velocity in rough nanochannels, 77 due to the smoothness of the inner walls of CNT, as shown in previous theoretical and experimental researches, 60 , 70 , 71 , 75 and our previous studies also show that methane flow in nanochannel constructed by smooth graphene has much higher velocities than that in rough nanochannel. 66 …”

“…MD has been employed to investigate diverse properties of shale gas in kerogen nanopores. This includes exploring adsorption and transport behaviors in nanochannels with different cross-sectional shapes, varying roughness of the wall surface, , and nanochannels containing functional groups. , Stickly layer also impact the transport of methane molecules, and carbon dioxide could enhance gas recovery. , In our recent work, we delved into the adsorption and transport behavior of methane nanofluid in straight nanoslits, considering different π – π stacking configurations . However, the majority of existing research has primarily explored properties in straight nanochannels, overlooking the effects of curvature and tortuosity.…”

“… 64 , 65 In our recent work, we delved into the adsorption and transport behavior of methane nanofluid in straight nanoslits, considering different π – π stacking configurations. 66 However, the majority of existing research has primarily explored properties in straight nanochannels, overlooking the effects of curvature and tortuosity.…”