Compositional modeling of interfacial tension effects in miscible displacement processes

Bette, S., Hartman, K.J. and Heinemann, R.F., 1991. Compositional modeling of interfacial tension effects in miscible displacement processes. J. Pet. Sci. Eng., 6: 1-14. An equation-of-state compositional model with a simple representation of the influence of interfacial tension on relative permeability, capable of simulating a wide range of miscible flooding applications, is presented. The model equations and the solution procedure are outlined. The model is applied to both hydrocarbon and CO2 injection schemes to simulate condensing and vaporizing gas-drive mechanisms. The calculated results compare very well with the laboratory measured values for immiscible, multiple-contact miscible, and first-contact miscible displacements. These simulations are predictions and no attempt is made to history match experimental observations. The successful simulation of miscible displacements under a broad range of operating conditions hinges on the treatment of the effect of interfacial tension on relative permeability. Some results from a CO2-slim tube displacement of a real reservoir fluid are also presented.