Phase behavior in shale remains a challenging problem in the petroleum industry due to many complexities. One complexity arises from strong surface-fluid interactions in shale nano-scale pores. These interactions can lead to a heterogeneous distribution of molecules, which conventional bulk-phase thermodynamics fails to describe. The majority of current models for phase behavior in shale are based on bulk-phase thermodynamics. There are currently very limited experimental data for hydrocarbon phase behavior in shale systems.

In this talk, a presentation on recent findings by a multidisciplinary research team at Texas A&M on the hydrocarbon phase change in nano-scale capillaries using experiments, molecular simulation, and a pore-size-dependent equation of state. The team has used two experimental approaches based upon selected “model” porous materials: a) combination of a nano-channel device and epi-fluorescence microscopy, and b) modulated differential scanning calorimetry to accurately measure the effect of confinement on hydrocarbon phase behavior in shale. I will also present our recent results using molecular simulation and a pore-size-dependent equation of state to model these experiments.