With a model of foam wellbore flow and a model of foam seepage flow,a mathematical model of foam plug removal is given.The model is solved with numerical method.Distributions of foam pressure,foam quality,foam density along wellbore and wellhead and bottom pressure are discussed.Furthermore,variation of bottom hole differential pressure is given as wellhead back pressure is fixed.It shows that as foam pressure and density increases,foam quality decreases with increase of well depth and bottom hole differential pressure declines.

Foam microscopic seepage experiments show that foam present two seepage states: Flowing foam and trapped foam.Foam plugging experiment show that foam plugging ability has accumulating effect.Plugging pressure gradient near core inlet is less than that of downstream of the core when foam flooding reaches steady state.A multi-component mathematical model characterizing foam flooding is established based on bubble population balance theory and foam properties.The model is solved numerically with fully implicit method.Validity of the model is verified with foam plugging experiment.Meanwhile,foam microscopic seepage characteristic parameters such as foam texture,pressure and aqueous phase saturation in foam flooding are studied.