ABSTRACT
In this study, the rheological behavior of five types of Iranian vacuum residues (VRs) containing different values of asphaltene content is investigated under the effects of a wide range of temperature and shear rate. Rheological tests showed that the asphaltene content of VRs plays an important role on the viscosity of these fluids. The samples with higher content of asphaltene have higher values of viscosity and also higher yield point. The Bingham plastic and Herschel–Bulkley models were successfully used to model the rheology and yield behavior of VR samples at a wide range of shear rate and temperature.