Effect of Diluents on the Rheological Properties of Maya Crude Oil

Understanding the rheological properties of mixtures of heavy oil or bitumen and diluents, specifically at low temperatures, is key in designing different processes employed in the production or transportation of these resources reliably and efficiently. The effect of diluents (n-heptane, toluene, and toluene + butanone (50:50 vol %)) on the non-Newtonian behavior of Maya crude oil including shear thinning and thixotropy at temperatures from 258 to 333 K are discussed. Toluene + butanone (50:50 vol %) addition to Maya crude oil induces the greatest reduction in shear thinning behavior irrespective of temperature. Thixotropic properties of mixtures of Maya crude oil and diluent were studied through startup experiments. It was shown that toluene + butanone (50:50 vol %) is the best diluent in moderating the thixotropic effect, whereas n-heptane showed the most pronounced thixotropic effect. It was shown that toluene + butanone (50:50 vol %) is more promising in decreasing Oil viscosity in comparison to two other diluents tested. Less of this diluent is required to decrease the viscosity to a certain value, which confirms its potential to be used in the industry as a diluent. The results presented also provide a reliable database for model development and evaluation.