Development and application of polymetric surfactant emulsification and viscosity reduction system

Abstract

Compounding polymer AP-P4 with high viscosity-reducing Gemini Surfactant HD, which is used as an emulsifier viscosity reduce, to improve the stability of the O/W emulsion while the viscosity reduction rate is kept. A polymeric surfactant emulsification and viscosity reduction system capable of forming a relatively stable O/W emulsion of heavy oil (0.5% HD+0.1% AP-P4) is then compounded. The system has been characterized as a high viscosity reduction rate and high stability. Meanwhile, the production liquid does not need to be added with a demulsifier and only needs to be heated to 70 °C to achieve effective demulsification. The influencing factors of the performance of the polymetric surfactant emulsification and viscosity reduction system were studied. When the oil-water ratio was 70:30 and 60:40, the viscosity reduction rate was 97.47% and 99.09%, respectively; after 15 h at 30 °C, the dehydration rates were 95.8% and 99.2%, respectively. The dehydration rate after 15 h at 70 °C was 98.1% and 99.4%, respectively; at 30 ~ 50 °C, the water phase temperature has a greater impact on the viscosity; at 60 °C, 70 °C, the water phase temperature has little effect on the viscosity; as the temperature of the aqueous phase increased, the stability of the emulsion deteriorated. When the aqueous phase temperature was 30 °C, 50 °C and 70 °C, the dehydration rates of the emulsion after 15 h were 95.8%, 96.7% and 98.1%, respectively; As the degree of mineralization increases, the viscosity reduction rate decreases, and the stability of the emulsion deteriorates. The system has been used in field test for 2 injection wells, and the production rate of the two wells increased with a peak value of 25 m³/d and 20 t/d, respectively.

Keywords

Heavy oil / Wellbore viscosity reduction / Emulsification / Polymer / Dehydration rate

Acknowledgments

The Authors would like to thank for research Funding support of State Key Laboratory of Molecular Engineering of Polymers(Fudan University, Grant No.K2017-25), National Natural Science foundation of China (Grant No.51674208), Nanchong science and technology planning project (Municipal and university science and technology strategic cooperation special projects, Grant No.NC17SY4017) and the Applied Basic Research Programs of Sichuan Science and Technology Plan Project (Grant No. 2018JY0515).

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