As part of a study of steam and solvent co-injection processes for MacKay River reservoir, a number of fluid properties of MacKay River bitumen-solvent mixtures were measured for three candidate diluents (referred to as Solvents 1, 2 and 3) at conditions relevant to the co-injection process under consideration. They include viscosities of bitumen-solvent mixtures for Solvent 1 and 2, densities of bitumen-Solvent 2 mixtures of different solvent content and liquid-vapor phase behaviour of the bitumen-Solvent 2-water mixture at a given mixing ratio.

The results showed that the effectiveness of solvent-dilution on oil viscosity became less prominent as temperature increased. The differences among the diluents in lowering the viscosity of MacKay River bitumen were insignificant. At elevated temperatures and above the solvent saturation pressures, increasing solvent loading in the bitumen-Solvent 2 mixture from 10.7 vol% to 19.5 vol% reduced the density of the mixture by only 3 - 5%. At 1750 kPag, the bitumen-Solvent 2-water fluid mixture containing 5.8wt% of solvent and 58wt% of water remained as two liquid phases at temperature up to 165 °C. The mixture formed a three-phase system (one vapor phase and two liquid phases) at 195 °C, with only 6.8wt% of the solvent dissolved into the oil. Small quantities of C10+ components from the bitumen were also detected in vapor phase.

Mixture viscosities were calculated and fitted to a linear-logarithmic mixing rule. A good match with the measured viscosity was achieved at all temperatures below the bubble point of the mixture. K-values of the solvent pseudocomponents were determined using HYSYS and fitted to the correlation to estimate K-value as a function of temperature and pressure.

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