Self-diverting foamed system

摘要

A method is given for diverting acids in matrix acidizing and acid fracturing. The acids are diverted with a diverting agent that is an energized or foamed acidic viscoelastic surfactant system that contains a viscoelastic surfactant that gels and increases in viscosity when the acid in the foamed acidic viscoelastic surfactant system is spent. The method provides a synergistic combination of the diverting capabilities of foams and the diverting capabilities of viscoelastic gel systems. The resistance to flow of the gelled foamed viscoelastic surfactant system is greater than expected from a foam or a viscoelastic gel system alone.