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Introducing A Model Emulsion Replicating SAGD Reservoir Emulsion Features

  • Author / Creator
    Velayati, Arian
  • This thesis introduces a model emulsion that replicates the physical features of steam-assisted gravity drainage (SAGD) reservoir emulsion. Moreover, a framework was presented which enables adjusting the emulsion properties such as dynamic viscosity, size of the droplets, kinetic stability, and asphaltene precipitation to reach the target features accurately. For this purpose, the research followed two primary phases. In the first phase, a base recipe containing water, the external oil phase, and a non-ionic surfactant (Span 83) was selected and screening and comparative tests were carried out to determine the proper homogenization settings, assess the surfactant performance, add/introduce other surfactants/components such as gilsonite and hexane to the recipe and evaluate the effect of electrolyte, phase ratio, and additives concentrations on the features of the emulsions. The second phase of the research started once the decision on the final components of the model emulsion recipe was made. In this stage, BoxBehnken experimental design was adopted to run the experiments and establish correlations for the target features with the concentration of the additives/components. These correlations were used as objective functions in the optimization to attain the goals, which were SAGD emulsion features. This research employs different techniques to evaluate the emulsion properties. The kinetic stability of emulsions was monitored by optical microscopy, water phase separation in the bottle tests, and interfacial tension measurements. The viscosity of emulsions was measured by a cone and plate viscometer, and the size of the droplets and asphaltene aggregates were determined by optical microscopy. In addition to the primary objective of the research several other marginal objectives were followed. This research presents a comprehensive characterization of w/o macro-emulsions stabilized by a non-ionic surfactant (Span 83), where the effect of phase ratio, oil composition, electrolyte, and surfactant concentration on the emulsion features was investigated. Moreover, gilsonite is introduced as a new additive that can be used to mimic asphaltene precipitation in oil. Asphaltene precipitation in different oil blends was monitored and characterized, and the effect of gilsonite concentration, oil composition, electrolyte, and phase ratio on emulsions properties was studied. Molecular dynamic simulation coupled with experimental results in terms of water phase separation, interfacial tension measurements, viscosity measurements, and micrography reveal some important aspects of the asphaltene aggregation role in the stability of w/o emulsions. The application of the model emulsion is quite extensive. It can be used in sand pack and core flooding tests that currently neglect the emulsion flow. Utilizing model emulsion eliminates the need to run similar tests at high-pressure high-temperature conditions with bitumen, which is risky and hazardous, and can replace the difficult procedure of asphaltene extraction from bitumen. Additionally, the results presented in this research around asphaltene precipitation behavior and stability of w/o emulsions by asphaltene aggregates have important implications for solvent-SAGD operations.

  • Subjects / Keywords
  • Graduation date
    Fall 2021
  • Type of Item
  • Degree
    Doctor of Philosophy
  • DOI
  • License
    This thesis is made available by the University of Alberta Libraries with permission of the copyright owner solely for non-commercial purposes. This thesis, or any portion thereof, may not otherwise be copied or reproduced without the written consent of the copyright owner, except to the extent permitted by Canadian copyright law.