archives@tulane.edu / Enhanced oil recovery (EOR) and oil spill remediation (OSR) in porous media both share a common theme in that they can both be modeled as a system comprising of two immiscible liquid phases and a solid porous phase. EOR seeks to improve the recovery of crude oil from existing oil reserves, while OSR improves ecological sustainability. In this thesis two novel techniques with the potential of improving the recovery of non-aqueous phase liquid (NAPL) that is trapped in a water filled random porous media.
In the first project, an oil-soluble surfactant was studied to enhance crude oil mobilization in a cryolite-packed miniature bed. The cryolite packed bed provided a transparent, random porous medium for observation at the microscopic level. In the first part of the project, oil-soluble surfactants; Span 80 and Eni-surfactant (ES) were dissolved directly into the crude oil. The porous medium was imbued with the crude oil (containing the surfactants), and deionized water was the flooding phase, in this experiment, the system containing ES had the best performance. Subsequently, Sodium Dodecyl Sulfate (SDS), a hydrosoluble surfactant was used to solubilize the ES, with the SDS acting as a carrier for the ES to the contaminated porous media. Finally, the SDS/Eni-Surfactant micellar solutions were used in oil-removal tests on the packed bed. Grayscale image analysis was used to quantify the oil recovery effectiveness for the flooding experiments by measuring the white pixel percentage in the packed bed images. The SDS/ES flooding mixture had a better performance than the SDS alone.
Furthermore, a model liquid hydrocarbon (n-hexadecane) was used to gain insight on the mobilization of non-aqueous phase liquids (NAPLs) trapped in porous formations, important for both EOR and oil spill remediation in porous media. Food-grade surfactants lecithin from soy and tween 80 were compared to commercial dispersant Corexit 9500A, for their ability to mobilize the hydrocarbon originally trapped in a water-filled cryolite porous medium. Red dye was added to the n-Hexadecane to improve visualization, and the aqueous phase incorporated different ratios of the surfactants Lecithin and Tween 80 to seek synergistic benefits when the two surfactants are combined. Visual-microscopic flooding experiments carried on a miniature packed bed produced images which were then analyzed using grayscale image analysis. It was determined that a ratio 40:60 by weight of Lecithin to Tween 80 has the best performance in the mobilization of n-hexadecane from the porous media. Furthermore, any (non-optimal) mixture of lecithin and tween 80 exhibited a better (synergistic) performance in n-Hexadecane recovery from the porous media than when applying either surfactant separately.
Finally, applying the video-microcapillary technique utilized in the first two projects, but with a slight modification, the effect of temperature change on a highly viscous oil phase flowing through a water-filled porous media was studied. The glass microcapillary was coated externally with a thin film of Indium Tin Oxide (ITO) to render it electrically conductive. When an electric current is applied to the outside of the coated capillary, the temperature of the capillary can be elevated. The tapered region of the capillary is filled with cryolite to form a random porous media and flow experiments were conducted in this region. Applying this technique, we studied the flow pattern of a highly viscous oil displacing an aqueous phase in a porous media at 60, 70, 80, 90, and 100oC. Also, we observed capillary fingering, continuous, and Haines jump flow patterns, with capillary fingering and Haines jump more prominent at 10-3 capillary number, while flow at 10-2 exhibited continuous flow pattern.
Chapters 2 and 3 of this dissertation include content in peer-reviewed journal articles published by the author.1,2 / 1 / Chike George Ezeh
| Identifer | oai:union.ndltd.org:TULANE/oai:http://digitallibrary.tulane.edu/:tulane_92429 |
| Date | January 2019 |
| Contributors | Ezeh, Chike (author), (author), PAPADOPOULOS, KYRIAKOS (Thesis advisor), (Thesis advisor), School of Science & Engineering Chemical and Biomolecular Engineering (Degree granting institution), NULL (Degree granting institution) |
| Publisher | Tulane University |
| Source Sets | Tulane University |
| Language | English |
| Detected Language | English |
| Type | Text |
| Format | electronic, pages: 115 |
| Rights | No embargo, Copyright is in accordance with U.S. Copyright law. |
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