Density and viscosity of multicomponent diluent/bitumen mixtures with application to in-situ bitumen recovery and diluted bitumen transportation

Abstract

The extraction of bitumen relies on energy-intensive methods, and its transportation necessitates dilution due to its high viscosity. Hence, there is a growing demand to explore alternative approaches that are cost-effective and energy-efficient to enhance the extraction and transportation processes. While there is ample thermophysical data available in the literature regarding the individual performance of pure solvents and bitumen systems, there is a significant gap in data concerning density and viscosity measurements for multicomponent solvents and their interaction with bitumen. This study presents new measurements by investigating the effect of varying multicomponent diluent concentrations (7 to 70 wt%) on the density and viscosity of multicomponent diluent/Mackay River bitumen system in a pressure range of 1.291–8.769 MPa and a temperature range of 295–389 K. These thermophysical data are essential in the design, optimization, and reservoir simulation of solvent-based and solvent-aided recovery processes, as well as the surface processing and transportation of diluted bitumen. The findings demonstrated that the addition of the diluent, even at a lower mole fraction, has a notable impact on reducing both the density and viscosity of the bitumen. As part of this study, we have also obtained empirical correlations based on well-established relationships that can be employed as predictive tools for estimating the density and viscosity of a multicomponent diluent/bitumen system. The obtained correlations estimate the density and viscosity of mixtures of bitumen and diluent with average absolute relative deviations (AARD) of 0.4 % and 16.29 %, respectively. The new experimental data are then used to perform zeroth-order energy, greenhouse gas emission, and carbon tax recovery analyses of solvent-aided viscosity reduction. The results reveal that the utilization of natural gas condensate as a diluent leads to significant energy reductions and greenhouse gas emissions. The results find applications in solvent-based and solvent-aided bitumen recovery processes, surface processing, and the transportation of diluted bitumen.