Study on the influence mechanism of asphaltenes on the gelation and flow behavior of wax-containing simulated oils

Abstract

The precipitation of wax crystals will lead to the formation of gelation structures in waxy crude oils, and the presence of asphaltenes will affect the gelation and flow process of waxy crude oils. In this work, five waxy oils with different asphaltene contents were formulated, and the effect of asphaltene on the gelation and flow behavior of wax-containing simulated oils was investigated. The results show that asphaltenes can improve the low-temperature rheology of wax-containing simulated oils to a certain extent. When the asphaltene contents in wax-containing simulated oils increased from 0 wt% to 0.5 wt%, the pour points decreased from 25 °C to below 0 °C, while the gelation temperatures and storage modulus were also decreased from the initial 29.01 °C to 25.64 °C and 33262 Pa to 5.9 Pa, respectively. The results were due to the fact that the increase of asphaltene contents weakened the gelation network structure strength of wax-containing simulated oils and inhibited gelation process. Meanwhile, in the range of low asphaltene contents, the apparent viscosity of wax-containing simulated oils at 10 °C decreased from 531.5 mPa·s to 7.6 mPa·s with the increase of asphaltene contents.