Experiment Research of Flooding Efficiency on Alternative Injection of Low-Tension System and Foam System

To make binary low-tension system play a vital role in improving oil displacement efficiency and foam system expand swept volume, binary low-tension system alternates with binary foam system flooding laboratory research is carried out after the polymer flooding technology. The method of airflow is used to proceed with foaming performance experiments by nitrogen gas. Surfactant CYL which foaming performance is stronger has good compatibility with alkali-free surfactant. The evaluation of the interfacial tension experiments shows that surfactant HLX has a low interfacial tension; the HLX's ability of reducing interfacial tension is less affected by CYL. It is shown through experiment that displacement recovery of binary foam system is 7.84% and binary low-tension system is 5.87% after polymer flooding, as well as the injection pattern of (0.05PV binary foam system+0.05PV N2+0.1PV binary low-tension system) alternating three times is best, which displacement recovery is 14.22% and 12.26% in natural core after polymer flooding. The injection pattern of profile control and oil displacement can attain a perfect effect after polymer flooding.