(395f) Methane Mass Transfer in Liquid Hydrocarbon Mixtures – Measurement and Modeling in Synthetic Porous Media

Methane (CH₄) dissolution and mass transport in liquid hydrocarbon mixtures is of key interest in enhanced recovery from tight shales. In this research, we study experimentally CH₄ mass transport through synthetic model porous media saturated with liquid hydrocarbons, with the objective being to quantitatively investigate the effect of capillarity and pore structural characteristics on methane transport through such media. The overarching goal of our research is to gain a better fundamental understanding of the mechanism of methane dissolution and transport under nanoconfinement.

In our studies, we employ a high pressure and temperature Wicke-Kallenbach diffusion cell. Vycor 7930 and AGC-40 (Advanced Glass & Ceramics, LLC) porous glass with average pore size of 7 and 4 nm, respectively, are used as the model synthetic porous media. By monitoring the pressure drop in the bulk gas phase, we can measure the rate of dissolution and diffusion of CH₄ through the model porous silicas.

The phase behavior and transport properties of methane/hydrocarbon systems in the bulk have been well studied by our Group and others. However, the nanoconfinement of these fluid mixtures in tight rocks causes their physical behavior to deviate from the corresponding bulk phase behavior. In our study, we have developed a model that considers the impact of pressure difference across the vapor-liquid interface and of liquid swelling due to the methane dissolution in the pore space. The results of our study to date show that this model can predict the mass transfer behavior of methane/n-alkane systems in nano-confinement from the bulk-phase information.