Viscosity Prediction for Solvent-Diluted Live Bitumen and Heavy Oil at Temperatures Up to 175°C

Accurate predictions of heavy-oil and bitumen viscosity as a function of temperature, pressure, and composition are required for the design of thermal and solvent-based recovery methods. In this case study, the applicability of the recently developed Expanded Fluid (EF) viscosity model is tested on measured viscosities of diluted dead and live heavy oil and bitumen at temperatures from 20 to 175 degrees C and pressures up to 10 MPa. Density and viscosity data were collected for a condensate solvent, dead (gas-free) bitumen, and dead heavy oil from western Canada, and for the corresponding live oils and diluted mixtures of the dead and live oils with condensate solvent. Solubility, density, and viscosity data for heavy oil saturated with carbon dioxide (CO2) were obtained from the literature. The model was fitted to the data of the dead oils and the condensate with average relative deviations less than 11%. The viscosity of the live bitumen and heavy oil was then predicted to within 21 and 31% of the measured value on the basis of measured and calculated live-oil densities, respectively. Diluting the live and dead bitumen with 3 to 30 wt% condensate or carbon dioxide reduced the viscosity by one to three orders of magnitude, and the viscosities were predicted with an average relative deviation less than 16 and 24% on the basis of measured and calculated mixture densities, respectively.