Viscosity Modeling of Solvent-Heavy Oil/Bitumen Systems at High Pressures and Elevated Temperatures

This work presents a novel framework for reproducing the measured viscosity of solvent-heavy oil/bitumen systems by integrating the Peng-Robinson equation of state (PR EOS) with binary interaction parameters (BIPs) and modified alpha functions. The oil samples are treated as either as a single pseudocomponent (PC) or multiple PCs. Also, the six most common mixing rules (i.e., Arrhenius’ mixing rule, Cragoe’s mixing rule, double-log mixing rule, Lobe’s mixing rule, power law mixing rule and Shu’s mixing rule) have been evaluated and compared. By adopting the effective density concept, the volume-based power law, weight-based power law, and weight-based Cragoe’s mixing rules reproduce the measured viscosity from 4.3–15000.0 mPa·s within the pressure and temperature range from 1.1 to 10.9 MPa and from 287.9 to 463.4 K. When utilizing one PC, the overall absolute average relative deviation (AARD) for viscosity prediction is found to be 16.0%, 16.5%, and 29.4% for the aforementioned mixing rules. When utilizing four PCs, the AARDs decrease to 13.9%, 14.8%, and 19.3% for the same mixing rules. It is evident that such framework has ability to predict solvent-heavy oil mixture viscosity reasonably accurate under various conditions, while it can be easily incorporated into any reservoir simulators within a given reservoir.