Abstract:

High-wax crude oil often has the features of high density, high viscosity, and high pour point, which leads to high costs during exploitation, transportation, and storage. To overcome the above problems, in this work, two polymers were synthesized via free radical polymerization. The two polymers and their blends were used as viscosity reducers to improve the flowability of high-wax crude oil. The copolymer P1 was synthesized by using nonyl acrylate and vinyl acetate as monomers, while the copolymer P2 was synthesized by using dodecyl acrylate and methyl methacrylate as monomers. The effects of polymer amount on the viscosity parameters, pour point and shear stability index of high-wax crude oil were studied, in which the two copolymers and their blend P3 acted as pour point depressants. The experimental results showed that P1, P2, and P3 all had significant pour point depression and drag reduction performance, among which P3 was the best. At a dosage of 4%, P3 could reduce the pour point of the crude oil sample from 28.3 ℃ to 4.4 ℃ and the viscosity could be maximally reduced by 75.293%. The results of shear stability analysis showed that, the adverse effects of high-speed shear on freezing point and viscosity reduction were not very significant in presence of P3 （The freezing point was merely raised by 2.1 ℃ after high-speed shear and the viscosity reduction rate was merely decreased by 5.76% after high-speed shear）, and the PVL and PSSI values were small at all concentrations, indicative of good shear stability. Therefore, P3 was expected as an efficient pour point depressant and drag reducing agent which could effectively reduce the viscosity of high-wax crude oil and reduce the drag during transportation, and thus reduce the energy consumption during pipeline transportation.

Key words: polymer blend, pour point depressant and drag reducer, fluidity, energy conservation and emission reduction