Understanding pore-level phenomena of n-alkanes at high pressures

Abstract

Adsorption of shale related n-alkane fluids in graphite nano-channels is studied. Pure component canonical (NVT) ensemble simulations are performed over a range of isotherms and pore widths. Results for n-hexane are used to validate our approach by comparing them with experimental data in the open literature. The impact of pore throat diameter on adsorption and internal energies of departure is also reported and further demonstrate that there is a carbon chain length dependence on adsorption. All pure component results reported in this work are fit to a Langmuir adsorption model, which provides easy re-use in future studies. Numerical adsorption results for pure component methane adsorption are compared to experimental reservoir conditions. Finally, Ideal Adsorbed Solution Theory (IAST) is applied to the resulting Langmuir isotherms in order to provide some insight into the phase equilibria for applicable shale gas mixtures.