Quantification of Mutual Mass Transfer of CO2/N2–Light Oil Systems by Dynamic Volume Analysis

Abstract

A novel and pragmatic method has been developed to quantify mutual mass transfer between a gas (e.g., CO2 and N2) and light oil by dynamic volume analysis. Experimentally, diffusion experiments for pure CO2/N2-light oil systems are conducted at a constant pressure and temperature with a pressure/volume/temperature (PVT) system. During the diffusion experiments, the diluted volume of oil phase is continuously monitored and recorded, while gas samples are collected at the end of the diffusion tests to measure gas compositions by performing gas chromatography (GC) analysis. Theoretically, the mass transfer from light oil to gas phase and the solubility of a gas into the light oil is quantified by combining the GC analysis and Fick’s second law, while the Peng–Robinson equation of state is employed to determine the concentration of each gas component in the oil phase by imposing the quasi-equilibrium boundary condition at the gas–oil interface. The diffusion coefficient of each component can be determined onc...