Investigation of interfacial mass transfer in vapour extraction process.

摘要

Vapex (vapor extraction) is a relatively new process for the recovery of heavy oil and bitumen that involves the injection of a vaporized solvent to reduce the viscosity of the oil. The diluted oil is then allowed to drain into a production well under the influence of gravity. It is a potentially economic process that can be applied to reservoirs that are not suitable for thermal recovery method. In addition, the process has the potential to sequester greenhouse gases, and is capable of in situ upgrading of heavy oil.; The primary objective of this research was to identify the main processes governing the interfacial mass transfer of solvent into bitumen. The influence of convective dispersion and concentration-dependent-diffusivity on mass transfer in Vapex was examined. This research began with experiments in Hele-Shaw cell to verify the validity of the existing analytical models of Vapex. Experiments in Hele-Shaw cell revealed that a convective dispersion due to momentum variation is created which in turn enhances the mass transfer of solvent into bitumen.; The research was then extended to experiments in Sandpack to investigate the role of convective dispersion in porous media. Due to the existence of sand particles making up the porous media, the nature of the dispersion is different than that in Hele-Shaw cell. Results of the sandpack experiments conducted in this work and the experiments reported by others revealed that the dispersion in Vapex was considerably more pronounced than what would be predicted from the correlations reported in the literature. A new correlation incorporating the viscosity ratio and the Peclet number was developed and validated against the available experimental results.