Abstract: The dispersion and viscosity reduction effects of seventeen surfactants and nano-ZnO and nano-Fe₃O₄ on Xinjiang heavy crude were studied, the surfactants including Tween-80 and dodecylbenzene sulfonic acid, etc. The composition and structure of the asphaltene in Xinjiang heavy crude were characterized by element analysis, gel permeation chromatography, Fourier transform infrared spectroscopy,etc,and the mechanism of viscosity reduction was discussed based on the rheological test results of heavy crude. The results showed that the YTSZ-2 dispersion viscosity reducer composed of Tween-80, sodium dodecylbenzene sulfonate and nano-ZnO had good dispersion viscosity reduction effect, the viscosity reduction rate of Xinjiang heavy crude reached 44.34% at the condition of 65 ℃ and dosage of 200 mg/L. The thickness, diameter and number of aromatic layers decreased with the increase of asphaltene lamellar spacing, and the asphaltene particle size decreased, thus the viscosity of heavy oil decreased.

Key words: heavy crude oil, asphaltene, dispersion, viscosity reducing, surfactant