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 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 (CO 2 ) 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.

Summary One of the issues for the pipeline transportation of diluted bitumen (dilbit) is the fate and behaviour of the dilbit if it is spilled in freshwater systems; in particular, the evaporation rate and the change in physical properties of the film after evaporation and exposure to water (weathering). In this study, the evaporative weathering of dilbit Cold Lake Winter Blend (CLWB) and light crude oil Alberta Sweet Blend (ASB) films were compared. Evaporation rates were measured for films on glass over time (up to 30 days) at different air-flow rates and at temperatures of 5, 15, and 25C. The solvent content, density, and viscosity of the films were measured after different weathering times. A second set of tests at 15C was performed on both dilbit and light-crudeoil films on water. As expected, the mass-transfer rate increased with increasing temperature and decreasing film thickness in all cases. The evaporation of the dilbit was found to be limited by the diffusion rate of the lighter components through the film while that of the light crude oil was limited by convective mass transfer to the air above. The density and viscosity of both the CLWB and ASB films correlated to the amount of evaporated material at all conditions examined, including different film thicknesses, temperatures, and air-flow rates. It appears that the volatile components evaporate in the same order at any conditions; therefore, film composition, density, and viscosity are only functions of the amount evaporated. The evaporation rates, density, and viscosity of CLWB and ASB films weathered over water were identical to those corresponding films weathered on glass, within the error of the measurements; that is, contact with still water had no effect on weathering.