Ternary Complex Phase Behavior Characteristics Of Experimental Research,

Alkaline/surfactant/polymer (ASP) flooding is a kind of effectual enhanced oil recovery method, which offers the powerful technological guarantee to sustainable development of oil fields. Both of research work of flooding mechanism and formulation optimization of ASP system is the key that technology develops further. The accurate description of complicated physical and chemical change characters occurred during ASP flooding is vital to enrich the flooding mechanism and formulation optimization, phase transition theory is an important way to study physical and chemical change. This paper discussed static phase behavior, dynamic phase behavior and phase transition in ASP flooding.The results showed that middle phase could be formed between upper phase and lower phase by the interaction of ASP system and oil phase. The middle phase volume is related with the factors, which mainly include surfactant concentrations and salt concentrations etc. The experiment results showed further that salt can compress the double layer of ASP system and its concentration is quite sensitive to interfacial tension (IFT) and middle phase.Through the primary study of the rheological characters and flow characters among porous medium of ASP system, it has been discovered that emulsion is the major conformation of oil-water mixture zone during ASP flooding and it presents the power law fluid character under the medium-size flow rate condition. The dynamic phase behavior study showed that the form of middle phase is a dynamic course and IFT will be stable while phase transition is steady. Dynamic IFT is chiefly induced by the new-formed surfactant from organic acid in crude oil and alkaline in ternary composition system.This paper discovers that salt can partly substitute alkaline during ASP flooding through physical simulation experiment in laboratory evaluation, which can prevent some un-favorable factor including well-bore scale buildup and emulsification of produced liquid etc. It can optimize compound system prescription to enhance the recovery as well, and the ideal economic benefits also will be obtained.