An Investigation of the Robustness of Physical and Numerical Vanishing Interfacial Tension Experimentation in Determining CO2 + Crude Oil Minimum Miscibility Pressure

Different experimental and theoretical methods are used for predicting the minimum miscibility pressure (MMP) of complex CO2 + reservoir crude oil systems that are of particular interest to petroleum industry. In this paper, published physical and numerical vanishing interfacial tension (VIT) experimentations are critically examined for identifying best practices to reliably predict the CO2 + crude oil MMP. Some of the reported physical VIT experimentation studies appear to follow a portion of full scale VIT experimentation (i.e., a combination of the pendent drop method and the capillary rise technique). The physical VIT experimentation method in which the IFT measurements are made at varying pressures but with the same initial load of live oil and gas phases in the optical cell seems to be the most robust mechanistic procedure for experimentally studying the pressure dependence of IFT behaviors of complex CO2 + crude oil systems and thus determining the MMP using the VIT technique. The results presented here suggest that a basic parachor expression based on numerical VIT experimentation can reasonably follow the physical VIT experimentation in low IFT region, provided measured input data such as equilibrium phase densities and compositions are used in calculations