Study on the Foamability and Its Influencing Factors of Foaming Agents in Foam-Combined Flooding

Based on a series of static foaming experiments of foam-combined system, and by introducing a parameter, the comprehensive foamability, this paper put forward a new method to evaluate the foaming characteristics and foam stability of foam-combined system. Moreover, this paper has set up corresponding empirical formula. In glass capillary test, the effects of surfactant type, surfactant texture, polymer molecular weight, alkaline concentration, salinity of formation water, temperature, and crude oil property on comprehensive foamability of foam-combined system were investigated and discussed, respectively. The results showed that the reasonable critical values of surfactant concentration, alkaline concentration and polymer concentration were desirable for foam-combined flooding. In addition, the comprehensive foamability decreases with the increases of water salinity, temperature and content of light crude. For different kinds of surfactants, the foamability of sulfate-type is the best, and the sulfonate-type is less. While for the same kind of surfactant, the foaming effect gets better with the increase of carbochain, but when the carbochain increases to a certain length, the foaming ability of this surfactant decreases. By use of the definition of comprehensive foamability, in glass capillary test method, many research works done by other workers under different added liquid amount and glass capillary diameters can be compared under the same operation condition determined by the author.