Simulating Foam Processes at High and Low Foam Qualities

Abstract

Abstract Foams used for gas or acid diversion exhibit two flow regimes, depending on foam quality. Two foam simulators, one the most widely used commercial foam simulator and the other developed at our university, fit steady-state foam behavior in both regimes. A simple procedure is described for fitting simulator parameters to a set of steady-state coreflood data and examples are shown. Fitting model parameters to a single coreflood data can err by fitting this datum to the wrong flow regime. Shear-thinning reported in the "low-quality regime" can increase foam injectivity in radial flow. Foams in low-quality regime fit the same correlation for overcoming gravity override previously derived for foam in the high-quality regime. The flow regime does greatly affect the effect of capillary crossflow on foam diversion between layers differing in permeability, however. Capillary crossflow harms diversion between adjacent layers, as found earlier, but the magnitude of the effect is much less for foam in the low-quality regime, and no single correlation matches all the results. Capillary crossflow can actually increase (by a small amount) diversion from adjacent layers differing somewhat in permeability to distant layers with much-different permeability.