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ENCIT 2020
18th Brazilian Congress of Thermal Sciences and Engineering
Stability and injectivity of oil-in-water emulsions stabilized by stearic acid as natural lipophilic surfactant
Submission Author:
Alandmara Rosa Dionizio Leôncio , RJ , Brazil
Co-Authors:
Alandmara Rosa Dionizio Leôncio, Rafael Valladares de Almeida, Ranena V. Ponce F., Marcio CARVALHO
Presenter: Alandmara Rosa Dionizio Leôncio
doi://10.26678/ABCM.ENCIT2020.CIT20-0275
Abstract
Stable emulsions are often formed in almost all phases of crude-oil production due to the presence of natural crude oil surfactants, such as asphaltenes, resins, oil-soluble organic acids, solids, and waxes. This molecules stabilizes the oil-water interface though chemical interaction between them and other species in the water phase forming a resistant interfacial film. This work aims to study the formation and stability of emulsions stabilized by a fatty acid as natural surfactant in a oil-water model system, under ambient and high-pressure conditions, and their flow behavior through injectivity tests in sandstones. To this end, study of emulsion stability and interfacial rheology analysis were performed by evaluating the droplet size distribution (DSD) and interfacial viscoelastic modulus as a function of the surfactant concentration, aqueous composition, and flow conditions. In the rheological tests, results showed that the presence of the fatty acid in the oil phase promoted a reduction in the oil-water interfacial tension (IFT) and elastic modulus larger than the viscous modulus, evidencing important surface activity. All emulsions formed with a buffer solution without salts were stable under ambient conditions. During emulsion injection in single-phase flow, water mobility control was observed through the reduction of the absolute permeability as a strong function of emulsion DSD and capillary number (Ca).
Keywords
Natural surfactants, oil-in-water emulsions, emulsion stability, Interfacial rheology, Injectivity tests
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