Applying Fractional-Flow Theory to Foam Processes at the "Limiting Capillary Pressure"

SUMMARY A fractional-flow analysis is extrapolated from laboratory data for foams at the "limiting capillary pressure." This analysis suggests that for continuous-injection foam processes, the best surfactant should drive water saturation to the lowest possible value and be sensitive to permeability. For WAG processes, the best surfactant should cause foam to degrade over a range of water saturations.