Properties of Surfactant Solution for Foam-Flooding

The chemical flooding in Daqing Oilfield has entered the following water flooding stage, and about more than 50% of the crude oil remains in the reservoir. In order to maintain the sustainable and effective development of oilfield, the formulation of chemical flooding system suitable for after chemical flooding is studied. The surfactants in field application at home and abroad were investigated. The foam and interfacial properties of the surfactants were measured through a foam scanner and an interfacial tension tester. The properties of the surfactant system were optimized by using compound method. The injection pressure and oil displacement effect of surfactant system were studied by physical simulation experiment. The results show that the compatibility of DWS or AOS with oilfield sewage and polymer is good, and the foaming property and foam stability of DWS or AOS with polymer binary system are good. The ultra-low interfacial tension is formation between DWS and crude oil under oilfield sewage conditions. The foaming property and foam stability of DWS/AOS or DWS/RFD system are good. When the binary system is aged for three months under the condition of nitrogen, the viscosity retention rate is more than fifty percent. The viscosity stability under the condition of nitrogen is better than that in the air. When the liquid–gas ratio is 1:1, the pressure gradient and displacement effect of foam-flooding are the best. This gives a method to improve oil recovery after chemical flooding and provides a basic guarantee for oilfield development.