Phase Behavior of Alkanes in Shale Nanopores

This thesis is an analysis of the effect of shale nanopore confinement on fluid phase behavior using Monte Carlo molecular modeling. Research conducted so far in this area in the oil and gas industry mainly encompasses single component fluids and sorption densities in few PVT conditions. Many outstanding questions exist such as the concept of fluid pressure in confinement, multi-component fluid sorption and phase behavior/transition in confinement and the effect of pore type, geometry and heterogeneity on sorption capacity, some of which this thesis aims to answer. The confinement effect is first investigated for single component fluids using the grand canonical ensemble of Monte Carlo. In addition to phase diagram shifts, results show that in confinement the gas phase is affected greater than the liquid phase. It is shown that the three fluids of methane, n-butane and n-octane approach their bulk behavior at approximately 12nm width slit-shaped confinements. The investigation is extended to multi-component fluids using the NPT-Gibbs ensemble Monte Carlo. It is concluded that in mixtures, light components affect and suppress the phase diagram greater than heavy components. Furthermore, some preliminary studies were also conducted in the area of fluid adsorption in SWCNT. Ultimately, it is concluded that current equations of state cannot accurately predict and describe fluid behavior in shale nanopores and therefore new correlations need to be sought for