Abstract: In this paper，the reservoir of Gudao second district is a target area，and low interfacial tension foam flooding system
to adapt to reservoir condition is developed. Through performance evaluation of foam，foam system interfacial properties and
simulation test，foam performance，oil-water interfacial properties and block pressure in porous media，the ability to enhance
oil recovery，different pressure changes and cut water changes are studied. Testing proves that the low interfacial tension foam
flooding system has the characteristic of foam and surfactant. It can be on the double action of powerful washing and adjusting.
Foam selective plugging and high apparent viscosity increase flooding systems affected area，and the activity of low interfacial
tension foam system increase the displacement efficiency，and reduce the presence of residual oil，so that the foam system is
more stable after injecting the foam system，the integrated oil recovery increased by 28%.

Key words: foam flooding, low interfacial tension, oil recovery, cut water, block pressure