The effect of capillary condensation on the phase behavior of hydrocarbon mixtures in the organic nanopores

ABSTRACT

In nanoscale pores, the adsorption of gas is a multilayer adsorption process, and the conventional Langmuir model is no longer valid. In particular for the unconventional gas condensate reservoir, the adsorbed gas will become condensate once the pressure is above the critical condensate pressure at pore scale. In this study, considering the effect of adsorption (wetting) film, the multicomponent Kelvin equation is modified to computing the isotherm of capillary condensation. Then it is coupled with the multispace adsorption model and Peng-Robinson equation of state to investigate and represent the phase behavior of hydrocarbons in organic nanopores. Then, a prediction process for the behavior of a four-component mixture of methane, n-butane, n-pentane, n-hexane are performed. The actual Marcellus shale gas is also used to examine the performance of this model.

KEYWORDS:

• Adsorption
• EOS
• nanopore
• phase behavior
• unconventional gas condensate

Funding

The authors gratefully acknowledge the financial support of NSERC/AIEES/Foundation CMG and AITF Chairs. The support of National Program on Key Basic Research Project (Grant 2015CB250906) is also acknowledged.