Measurement and Evaluation of Bitumen/Toluene-Mixture Properties at Temperatures Up to 190?°C and Pressures Up to 10 MPa

Abstract

Summary The viscosity of bitumen and heavy oil is extremely high at both reservoir and surface conditions, on the order of 1 million cp. Therefore, viscosity reduction is necessary for production from the reservoir, pipeline transportation, and oil processing. The aim of this study is to evaluate the effect of different parameters (temperature, pressure, and solvent-weight fraction) on the density and viscosity of bitumen-containing mixtures. Thus, the density and viscosity of mixtures are measured for a sample of Athabasca bitumen diluted with different fractions of toluene at pressures from 0.1 to 10 MPa and at temperatures from 22 to 190 °C. The mixture densities show a linear decrease with temperature, pressure, and solvent concentration. The viscosity of the mixtures indicates a curvilinear trend with respect to the solvent-weight fraction and temperature. The effect of pressure on the mixture viscosity is more pronounced at lower-solvent-weight fractions. The mixture-density data are evaluated with two different methods: no volume change upon mixing and excess volume. The excess-volume method predicts the mixture-density data with an overall average absolute relative deviation (AARD) of 0.34%. The viscosity data for mixtures are compared with different models: Arrhenius (1987), Cragoe (1933), Shu (1984), Lobe (1973), double-log (Yarranton et al. 2013), Lederer (1933), power-law (Kendall and Monroe 1917), and Bij (Yarranton et al. 2013). The Bij model (Yarranton et al. 2013) produces the most-reliable results for mixture viscosities, with 5.5% AARD.