Solvent-aided bitumen production from oil sands has shown promise as an alternative to thermal recovery methods. Phase behavior studies of solvent/bitumen mixtures are necessary for reservoir simulation of recovery methods, process design and operation of surface facilities, and transportation. Bitumen and heavy crudes comprise a different weight fraction of asphaltene. In this study, the effect of asphaltene on phase behavior, viscosity, and density of solvent/bitumen systems is studied. Ethane (C2H6) and carbon dioxide (CO2) are considered as solvents. Phase behavior studies and property measurements are conducted on solvent/bitumen and solvent/deasphalted bitumen systems. Solubility of C2H6 and CO2 in the original and deasphalted bitumen are measured. The viscosity and density of the liquid phase are also measured by inline viscometer and densitometer at temperature and pressure ranges of 70–130 °C and 2–8 MPa, respectively. The measured data showed that the asphaltene has no significant effect on C2H6 solubility in bitumen. However, the solubility of CO2 in the original bitumen differs from that of the deasphalted bitumen. The significant effect of asphaltene on density and viscosity of bitumen is also quantified. Mixing rules are also employed to estimate the density and viscosity of asphaltene using the density and viscosity of bitumen and deasphalted bitumen.

Solvent-aided thermal recovery processes have recently gained practical and research interests among other thermal recovery methods due to their reduced environmental footprint and superior energy efficiency. One of the main challenges in design of solvent-based methods is selection of an appropriate solvent that maximizes the bitumen and solvent recoveries. This study attempts to introduce dimethyl ether (DME) as a non-conventional solvent for heavy oil and bitumen recovery. To investigate the performance of the proposed solvent, thermophysical properties of DME/bitumen are studied. Vapour-liquid equilibrium measurements including solubility, density, and viscosity are performed at three temperatures (100, 125, and 150 8C) and pressures up to 6 MPa. The results were compared with propane/bitumen and butane/bitumen systems. All the measured properties fall between propane and butane systems. The solubility and density data were fairly represented using PR-EoS with AARDs of 10.3 and 1.43 %, respectively, and viscosity data were correlated applying the Pederson corresponding state model with an AARD of 10.7 %. The results suggest that DME is a suitable substitute for solvents such as propane and butane in solvent-aided thermal recovery of bitumen from oil sands.

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We introduce ethyl acetate (EA), a bio-based chemical, as a potential solvent for bitumen recovery through comprehensive phase behavior and numerical simulation studies. Phase behavior and thermophysical properties of EA/live bitumen are measured at temperatures and pressures up to 190 C and 4 MPa, respectively. Experimental studies suggested that coinjection of EA with steam can reduce the bitumen viscosity by several orders of magnitude. Our numerical simulations show that coinjection of 2-8 mol% EA with steam can significantly reduce the steam-oil-ratio (SOR) by almost 0.9 units while increasing the bitumen production rate. This reduction in SOR can be translated to significant energy saving of~2.2 GJ, emission reduction of~120 kg of CO 2 , and wastewater reduction of~120 m 3 per ton of the produced bitumen, which are almost 20-25% lower than the steam-assisted gravity drainage (SAGD) process.

The gravity drainage as a result of viscosity reduction is the main governing mechanism of the solvent-aided thermal bitumen recovery processes. Therefore, the density and viscosity of the diluted or heated bitumen are essential to predict the oil production rate. In this paper, we report thermophysical properties of n-pentane/bitumen and n-hexane/bitumen mixtures. The density and viscosity of Athabasca bitumen diluted with n-pentane and n-hexane were measured at different temperatures (30 to 190 8C), pressures (2 to 8 MPa), and solvent mass fractions (0.05 to 0.5). Various correlations and mixing rules proposed in the literature were examined to calculate the density and viscosity of the diluted bitumen. This study proposes appropriate mixing rules and generalized parameters for predicting the density and viscosity of solvent-bitumen systems. Our findings will find applications in the design and simulation of heavy oil and bitumen solvent-aided thermal recovery processes.