Adsorption behavior modeling of confined hydrocarbons in shale heterogeneous nanopores by the potential theory

Abstract

In this article, a new method is proposed to quantificationally evaluate the effect of pore heterogeneity on the adsorption behavior of fluids in nanopores. First, the assumptions of furrowed, sinusoidal, and ravine pore surfaces are proposed to represent the heterogeneous nanopores in shale. Under the assumptions, a multicomponent potential theory of adsorption (MPTA) is coupled with Peng–Robinson equation of state (PR EOS) to model the adsorption behavior of hydrocarbons in nanopores. And, the geometrical and chemical heterogeneities in shale nanopores are, respectively, simulated by a spatial alteration and an amplitude deformation on potential energy. The fluid–fluid interaction is modeled by PR EOS, and the fluid‐pore wall surface interaction is simulated by a Steel 10‐4‐3 model for slit‐like nanopores and by a modified Lennard–Jones (LJ) 12‐6 model for cylindrical ones. Thereafter, the results of our theory are compared against the experimental data of shale rocks to validate its accuracy.

Surface-Molecule Interaction Strength on CO2 Adsorption Capacity in Nanopores: Implications to Advance CO2 Sequestration Performance

“…Therefore, manipulating molecule−surface interaction strength, like modifying the surface compositions, adding specified atoms on the surface, or reducing the distance between surface and molecules, is capable of varying CO 2 behavior in nanopores. 18,19 As for the CO 2 geological sequestration, we always pursue the purpose of advancing the storage capacity of the found geological site. Hence, changing the way a surface interacts with CO 2 molecules may supply a new pathway to promote the CO 2 storage capacity.…”

“…As reported, thickness of the adsorption phase CO 2 ranges from 0.4–0.8 nm, nearly 1–2 times the CO 2 molecular diameter. ,,, From the theoretical angle, the origin for the formation of the adsorption phase is the molecule–surface interactions. Therefore, manipulating molecule–surface interaction strength, like modifying the surface compositions, adding specified atoms on the surface, or reducing the distance between surface and molecules, is capable of varying CO 2 behavior in nanopores. , As for the CO 2 geological sequestration, we always pursue the purpose of advancing the storage capacity of the found geological site. Hence, changing the way a surface interacts with CO 2 molecules may supply a new pathway to promote the CO 2 storage capacity.…”