Phase Behaviour Study and Physical Properties Measurement for Athabasca Bitumen / Solvent Systems Applicable for Thermal and Hybrid Solvent Recovery Processes
Abstract
The development of solvent-based and hybrid (solvent + steam) processes is hampered by limited data and modeling methodologies for bitumen/solvent systems. The economics of these processes depend on the efficiency of oil recovery and solvent recycling, both of which are a function of the phase behaviour solvent/bitumen system. Additionally, accurate phase behaviour data are critical for pipeline transportation, surface upgrading, and the design of refinery processes. Despite its importance, the study of phase behaviour has received less attention. The quantitative effects of solvent on bitumen viscosity, density, and transport mechanisms are also not well understood.
The main aim of this research is to achieve a better understanding of the phase behaviour of bitumen/solvent systems at high temperatures approaching the conditions of in situ steam processes. The intention is not to develop recovery processes, but to provide the basic data and mechanistic understanding necessary for the quantitative assessment of these processes. This study focused on measuring and predicting the phase behaviour and thermo-properties of bitumen/solvent mixtures under different equilibrium conditions (single liquid, vapour-liquid, and liquid-liquid) over a wide range of temperatures (ambient to 200oC) and pressures (atmospheric to 10 MPa).
An in-house pressure-volume-temperature (PVT) apparatus was designed and fabricated with a new, reliable phase detection method. The equilibrium properties of bitumen/solvent including phase composition, solubility, k-values, and thermo-physical properties (density and viscosity) which are required for the optimization of heated solvent-assisted bitumen recovery processes were experimentally measured. The experiments cover a wide range of solvents including hydrocarbon gases (methane and butane), carbon dioxide, and liquid hydrocarbons (pentane, heptane, and toluene). The effects of the equilibrium conditions (temperature and pressure) and the initial solvent concentration on the measured properties were investigated. The qualitative phase diagrams were also developed and evaluated based on the measurements and the volumetric behaviour of the mixtures.
The correlation and prediction schemes were applied to represent the density and viscosity of raw bitumen and its mixtures diluted with liquid solvents. The bitumen was characterized and the Peng and Robinson equation of state was tuned and coupled with a characterization scheme to model the phase behaviour experimental data (density and solubility) for reservoir modeling purposes.
Description
Keywords
Engineering, Engineering--Chemical, Engineering--Petroleum
Citation
KARIZNOVI, MOHAMMAD. (2013). Phase Behaviour Study and Physical Properties Measurement for Athabasca Bitumen / Solvent Systems Applicable for Thermal and Hybrid Solvent Recovery Processes (Doctoral thesis, University of Calgary, Calgary, Canada). Retrieved from https://prism.ucalgary.ca. doi:10.11575/PRISM/27326