Effects of Paraffinic Group on Interfacial Tension Behavior of CO2–Asphaltenic Crude Oil Systems

The interfacial tension (IFT) of a crude oil/CO2 system is recognized as the main property affecting the efficiency of CO2 flooding during an enhanced oil recovery (EOR) process. The addition of a paraffin group hydrocarbon to asphaltenic crude oils as an asphaltene precipitant component is aimed to mimic the asphaltene precipitation process during crude oil production and transportation. Asphaltene precipitation would critically affect the interfacial behavior of crude oil/CO2 systems. In the first part of this study, the equilibrium densities of oil samples which contain n-heptane at different ratios were measured over varying pressures at 323 K. Then, the equilibrium IFT between CO2 and the crude oil samples was measured using the axisymmetric drop shape analysis (ADSA) technique. This investigation was followed by measuring the minimum miscibility pressure (MMP) of the oil/CO2 systems using the vanishing interfacial tension (VIT) technique. The results showed that the density of oil sample increases l...