Experimental Study on the Influence of Asphaltenes with Small Dosage on the Rheological and Gelation Behavior of Waxy Mixtures

Asphaltene, the heaviest and most polar non-hydrocarbon component in crude oil, may interact with waxes and affect the flow and gelation behavior of waxy oils. To further study the effect of asphaltene on the flow and gelation behavior of waxy oils, five wax-containing simulated oils with small dosage asphaltene content were prepared. Through pour point and rheometer test, it is found that asphaltenes can improve the low-temperature rheology of waxy oil. There is no critical turning point above which the low-temperature flowability improved. With an increase in asphaltene content from 0 wt% to 0.1 wt%, notable changes were observed in the properties of the waxy oil. The pour point, which measures the temperature at which the oil becomes too viscous to flow freely, exhibited a decrease from 25 ℃ to 13 ℃. Similarly, the gelation temperature, indicating the temperature at which the oil starts forming a gel-like consistency, also decreased from 29.0 ℃ to 27.1 ℃. These modifications can be attributed to the presence of asphaltene in the oil sample. This outcome can be attributed to the interference caused by the presence of asphaltenes, which disrupts the gel network structure of the waxy oil and consequently hinders its gelation process. Simultaneously, within the low asphaltene content range, an increase in asphaltene content resulted in a considerable decrease in the viscosity of the waxy oil at 10°C, reducing it from 531.5 mPa·s to 14 mPa·s.