Abstract
As a new type of oil displacement agent, nanofluid has shown great application potential in the field of enhanced oil recovery. Good dispersion and high stability of nanofluids are the prerequisites for engineering application. In this paper, the water-based graphene oxide (GO) nanofluid was taken as the research object, and the influencing factors of dispersion stability were systematically studied. The water-based nanofluid based on GO was formulated, and its oil displacement potential was studied. The effects of ultrasonic dispersion time, GO dosage and surfactant on the dispersion stability of GO in aqueous solution were investigated by turbidity experiment and conductivity experiment. The results showed that amphoteric surfactant disodium cocoamphodiacetate (CAD) had good dispersion stability for GO. CAD/GO dispersion not only decreased the oil/water interfacial tension to 10~(-2) mN/m, but also had good emulsifying effect and kept the emulsion stable. In the micromodel flooding test and core flooding test, CAD/GO dispersion effectively displace the residual oil in porous media and improve crude oil recovery. In the core flooding test, the oil recovery of CAD/GO dispersion (11.8%) was higher than CAD aqueous solution (6.7%), which was attributed to its better interfacial property and emulsifying property. These results indicated that the CAD/GO dispersion was promising for application in enhanced oil recovery (EOR).
NSTL