Investigation of water-in-oil emulsion on CSI solvent dissolution and ex-solution performance for heavy oil

The previous phase behavior studies of solvent and heavy oil systems were studied with cleaned tank oil samples only without considering the natural emulsion state of heavy oils, which does not fully reflect the proper fluid flow mechanisms at actual reservoir conditions. Therefore, in this study, the influence of water-oil emulsion on heavy oil's fluid properties and phase behavior was conducted. The effects of the water content on the physical properties of dead and live oils and their influence on the exsolution and dissolution processes of heavy oil mixtures were examined. The experiments used emulsion oils with three different water contents, 10%, 20% and 30 vol%. And the results were compared with the previous experimental data for pure oil only. Initially, the density and viscosity of emulsion stock tank oil (STO) at specified temperatures and pressures were measured. The measured emulsion oil densities and viscosities were compared with pure oil (Dong, 2020). The comparison results show that when the water content increased, the viscosity and density of the emulsified oil increased significantly. Furthermore, the interfacial tension (IFT) experiments for C1 and CO2 with emulsion STO were performed for pressure ranging from 1,000 kPa to 4,000 kPa and the temperature was set at 75°C and 15°C. The measurement results show that an increase in temperature and pressure can affect the measured IFT values. Next, the emulsion stock tank oils, with three different water content, were recombined with methane according to the specified gas-oil ratio (GOR). The resulting live oil samples went through the density and viscosity measurements the same as the dead oil. In addition, the Constant Composition Expansion and Compression (CCEC) PVT tests using the recombined emulsion live oils were conducted at 15 and 7°C with three different volume change rates (“Fast Rate” 1.5 cc/min; “Moderate Rate” 0.015 cc/min; and “Slow Rate” 0.0003 cc/min). For CCEC tests, the expansion stage starts with the initial pressure higher than the bubble point pressure of the live oil, then the system was depressurized at a fast, moderate or slow rate. Following that, the expansion process was reversed to the compression process when the expanded volume reached four times of the initial volume. The pressure was increased back to the initial pressure (11800 kPa) with the same rate as utilized in the expansion stage. For slow rate CCEC PVT tests, only an additional 15% of the volume expansion was required after the bubble point pressure was reached to save the test time. For all CCEC tests of live oil samples, the pseudo-bubble point pressures were determined from the slope changes of the plotted pressure-volume curves. The results prove that water content in heavy oil can significantly influence the heavy oil's physical properties and phase behaviour. This kind of research has seldomly been comprehensively examined and has never been published in the open domain based on our best knowledge. More specifically, the water content of the emulsion oil influences the density, viscosity, IFT and phase behaviour of the heavy oil systems to different extents. After analyzing the experimental data, it was found that the densities, viscosities increased, the IFTs slightly increased, and pseudo bubble point pressures decreased with the increasing water content up to 30% (this study only achieved up to 30% water content). Among these data analyzed, the effect of water content on the viscosity of emulsion oils is very pronounced.

Name thesis:degree_name

Master of Applied Science (MASc)

Level thesis:degree_level

Master's

Discipline thesis:degree_discipline

Engineering - Petroleum Systems

Grantor dc:publisher

Faculty of Graduate Studies and Research, University of Regina

Year dc:date.issued

2022

Author dc:creator

• Jiang, Jingwei

Advisor dc:contributor.advisor

• Jia, Na (Jenna)

Committee member dc:contributor.committeemember

• Shirif, Ezeddin

Language dc:language.iso

en

DOI

https://doi.org/10.82465/4186

OAI identifier oai:identifier

oai:uregina.scholaris.ca:10294/15534