It was proposed that the advanced⁃treatment of polymer⁃flooding produced water and realized the re⁃injection requirements. The feasibility and potential of further deep filtration treatment of wastewater containing polymer after ordinary treatment were studied by numerical simulation. The available advanced⁃filtration process pattern was established and optimized based on the distribution of oil droplets and suspended solid particles, the concentrations oil and suspended solid in filtered water, and the removal rates of oil and suspended solid. The results indicated that the advanced⁃filtration process pattern with "double graded⁃media + three graded⁃media" could further improve filtration performance depended on hydraulic and interfacial effects. The removal rates of oil and suspended solid reached 87.78% and 87.11%, respectively. The oil content and suspended solids of filtered water were controlled within 5 mg/L required for deep water treatment. This is a potential filtration process model for advanced treatment of polymer⁃containing wastewater, and also provides a basis for effectively dealing with water quality problems in tertiary oil recovery by chemical flooding in oilfields.

Surfactant/Polymer (SP) combination flooding is an effective method to enhance oil recovery of high quality reserves,while its surface produced liquid treatment technology and the simplification and optimization of operating parameters are both still a challenge for the promotion of the chemical flooding technology industrialization.In this paper,the emulsification of SP combination flooding produced liquid is characterized by multi⁃factor perpendicular experiments,and then the effect factors of demulsification and dehydration are studied.Significant test results indicated that,compared with the temperature and water cut,the effect of the concentration of surfactant and polymer in the produced liquid on dispersivity and electronegativity of the bulk was lower,which showed the greater contribution to emulsification stability of produced liquid,thus the demulsification of the produced liquid was declined.Bottle test experiments indicated that a single mechanism of improving demulsification temperature or prolonging demulsification time couldn’t fundamentally improve the dehydration rate of the produced liquid and reduce the oil content in the water after separation,meanwhile,the improvement of the pH of the water phase and the strong shear effect of the flow field would further deteriorate the effect of demulsification,dehydration and the water quality after separation.