Abstract:

The effects of Namontmorillonite(Na-Mt)particles on the oil-water interfacial properties and oil-water separation of polymer flooding produced water were experimentally investigated. By using an interfacial rheometer and Zeta potentiometer to analyze the influences of Na-Mt particles on Zeta potential, interfacial tension and dilational viscoelasticity of polymer flooding produced water, and the adsorption of the Na-Mt particles on oil droplets was observed under optical microscopy. The result showed that with the Na-Mt particles concentration increasing, and when the Na-Mt particle concentration was less than 200mg／L, the Na-Mt particles could cause the Zeta potential of oil droplets to rapidly decrease, interfacial tension to decline and dilational viscoelasticity to be enhanced. The results also showed that a stable oil-mineral aggregate(OMA) structure appeared in polymer flooding produced water, which had noticeable effects on emulsification stability of polymer flooding produced water. The polymer flooding produced water was stable in this stage. When Na-Mt particle concentration was higher than 250mg／L, the Zeta potential of oil droplets keeps stable, while interfacial tension and dilational viscoelasticity showed a slight increase. The system formed a large oil-mineral aggregate structure, which was  apt to aggregate, and could enhance the treatment of polymer flooding produced water.

Key words:  polymer flooding produced water, interfacial tension, dilational viscoelasticity; , Zeta potential, OMA structure