Fluid/Fluid and Fluid/Rock Interactions in Petroleum Systems: Implications to Emulsion Stability and...

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" Fluid/Fluid and Fluid/Rock Interactions in Petroleum Systems: Implications to Emulsion Stability and Wettability Alteration "
Rahham, Youssra Goual, Lamia

Document Type	:	Latin Dissertation
Language of Document	:	English
Record Number	:	1057041
Doc. No	:	TL56158
Main Entry	:	Rahham, Youssra
Title & Author	:	Fluid/Fluid and Fluid/Rock Interactions in Petroleum Systems: Implications to Emulsion Stability and Wettability Alteration\ Rahham, YoussraGoual, Lamia
College	:	University of Wyoming
Date	:	2020
Degree	:	M.S.
student score	:	2020
Note	:	162 p.
Abstract	:	The transport of petroleum fluids in flow lines and porous media is largely controlled by molecular interactions occurring at interfaces within the various fluids and by interactions between these fluids and rock surfaces. The presence of natural surfactants in crude oils and injected commercial ones to enhance oil recovery make these interactions even more complex. The goal of this thesis was to investigate the role of such surfactants in stabilizing oil-in-water emulsions and restoring the wettability of oil-wet carbonate rocks. This work was undertaken in two parts. In the first part, we extracted the interfacial material (IM) between crude oil and water phases and highlighted the differences between its structural properties and those of bulk asphaltenes. Although IM and asphaltenes possessed comparable molecular weights, IM molecules had a smaller aromatic core with a linear fatty acid chain containing a sulfinic or carboxylic group. This conferred them with an amphiphilic character that promoted their self-assembly into worm-like aggregates with a thickness of 2.5–9 nm and a length-to-thickness aspect ratio of 5. IM molecules interacted with water through their fatty acid chains while π- π stacking with adjacent molecules. Their growth favored the formation of 24 nm-thick nanosheets that lowered the oil/water interfacial tension (IFT). The nanosheets had a large surface area on which asphaltene clusters and fine clay particles adsorbed, compromising their stability. These new findings help in the future selection of effective demulsification strategies. In the second part, we used a novel in-house high-temperature-spontaneous-imbibition setup to systematically test a series of surfactants for their ability to reverse the wettability of sandy carbonates at reservoir temperature. The surfactants were characterized by state-of-the-art equipment for various properties. A special aging method was established where the initial brine saturation contributed to vast improvement in the cores’ oil-wetness. Correlations were established between hydrophilic and hydrophobic chain lengths and the surfactants’ performances. A tridecyl alcohol ethoxylate with 13 carbon atoms and 18 EO groups enhanced the oil recovery by 16% compared to blank brine. Moreover, a blend of cationic and nonionic surfactants at a ratio of 25:75 resulted in the highest ultimate recovery due to the combined effects of wettability reversal and IFT reduction. Blends including highly emulsifying cationic surfactants resulted in the highest ultimate recoveries; however, more than half the recovered oil was solubilized oil which would require post-recovery demulsification.
Descriptor	:	Engineering
	:	Petroleum engineering
Added Entry	:	Goual, Lamia
Added Entry	:	University of Wyoming