| dc.description.abstract | The phase behavior of petroleum fluids is an important factor in evaluating the hydrocarbon reserves and forecasting the oil and gas production behavior. Due to the existence of nano-scale pores, the fluid phase behavior in unconventional shale reservoirs differs significantly from that in unconventional reservoirs. Practically, the complexities of phase behavior in shale is associated with several factors, such as confinement effect, pore size distribution, surface uncertainty and heterogeneous distribution of hydrocarbon species. Previous work has mostly focused on theoretical studies and simulations. However, there are relatively few experimental data to verify the theories and models. A comprehensive picture of pressure-volume-temperature (PVT) behavior for the confined hydrocarbons remains uncertain.
This study, combined with laboratory and simulation studies, is dedicated to understand fluid phase behavior under nano-confinement effect from both experimental and theoretical aspects. Firstly, we developed an experimental technique of differential scanning calorimetry to measure the hydrocarbon liquid-vapor phase transition temperature in nanopores. Next, the experimental data is used to correlate a pore-size-dependent equation of state (EOS). The confinement parameters in EOS are determined and the EOS is shown to predict experimental results. With the pore-size-dependent EOS, a multi-scale PVT simulator is developed for shale’s nano-scale pore size distribution systems. The PVT simulator realistically models the constant composition expansion and
swelling behavior in gas injection for the shale reservoir fluids under macro- to nano-scale porous geometries. | en |
