Browsing by Author "Biswal, Sibani Lisa"

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    Investigation of Interfacial and Rheological Properties of Asphaltenes at Solid-Liquid and Liquid-Liquid Interfaces
    (2018-06-07) Lin, Yu-Jiun; Biswal, Sibani Lisa
    Asphaltenes are surface-active polyaromatic molecules in crude oil that are known to deposit onto surfaces of pipelines and stabilize water-in-oil droplets by flocculating at interfaces, resulting highly viscous emulsions. This has led to significant flow assurance problems in oil production. Therefore, a thorough investigation of the behavior of asphaltene aggregation at interfaces is needed. Microfluidic devices are used as a novel methodology for probing asphaltene deposition and asphaltene-stabilized emulsions. In particular, homogeneous and porous-media microfluidic designs are developed to represent various flow conditions typical of that found in oil flow processes. A variety of factors influencing asphaltene deposition are investigated, including asphaltene solubility, chemical dispersants, the presence of the brine, and solvent effects. Furthermore, the property of asphaltenes at interfaces is characterized using interfacial rheology and chemical analysis. By understanding the nature and the behaviors of asphaltenes at interfaces, we improve our ability to design cost effective mitigation strategies. This includes the development of a new generation of chemical inhibitors/demulsifiers and improved methods for prevention and treatment of this problem.
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    Microfluidic Investigation of Surfactant Foam Flow in Porous Media
    (2025-04-25) Wang, Yiwei; Biswal, Sibani Lisa
    Foams are ubiquitous in everyday life, with applications ranging from detergents and beverages to firefighting. They are also essential in industrial applications, including enhanced oil recovery in the oil industry and carbon sequestration in hydraulic fracking sites. Therefore, there is significant interest in understanding the fundamental physicochemical processes governing foam to predict its behavior in natural porous media environments. Microfluidics have proven to be effective in visualizing small-scale events and processes that are otherwise challenging to observe in natural confined systems. The work presented in this thesis investigates liquid surfactant foam flow in microfluidic porous media, focusing on foam transport dynamics and stability. In the first part of the thesis, the relationship between phase mobility and foam strength was investigated. By combining high-speed imaging and image processing, we provide an in-depth comprehension of foam texture, in relation to foam quality and flow. Additionally, the study probes the role of pore size in foam generation in porous media. The next body of work examines the interfacial viscoelasticity of different surfactant formulations and its role in foam generation in a single constriction device. Finally, carbon dioxide foam is studied at elevated pressure to assess the effect of gas solubility on foam stability, and surfactants with cationic, anionic, and nonionic head groups are screened for optimal foam strength. Overall, this work offers valuable insight into the generation, stability, and mobility of surfactant foam flow in porous media.