Spontaneous emulsification of water in oil at appreciable interfacial tensions

Silva, Pedro T. Santos; Zhdanov, S.A.; Starov, Victor; Holdich, Richard

doi:10.1016/j.colsurfa.2016.05.041

Cited by 31 publications

(36 citation statements)

References 19 publications

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“…Transport of water seems therefore also involving wetting phenomena between water and the quartz cell. A similar effect has been evidenced elsewhere 50 . Its main consequence is to considerably increase the exchange surface where SE can take place and therefore to speed up the overall increasing cloudiness of the samples.…”

Section: Qualitative Study Of Water Transportsupporting

confidence: 88%

Spontaneous Microstructure Formation at Water/Paraffin Oil Interfaces

et al. 2017

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An experimental investigation of spontaneous emulsification is proposed with a water drop pendant in a paraffin oil (PO) solution loaded with a surfactant (SPAN80). Optical microscopy in a transmission mode is employed for high-spatial-resolution image recording. The kinetics of spontaneous emulsification is studied. It is shown to generate a darkening of the drops because of interface modification with a characteristic time that depends upon the SPAN80 concentration. For low concentrations, spontaneous emulsification is slow and produces micrometer-sized droplets, whereas for large concentrations, it is fast and bush-like microstructures are observed. These microstructures increase in size and progressively invade the complete water/PO interfaces, detach, and finally migrate into the PO phase. This transport phenomenon withdraws water from the drops and leads to a gradual shrinking of their volume. At the end of this process, they appear as deformed objects surrounded by a loose membrane.

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Section: Qualitative Study Of Water Transportsupporting

confidence: 88%

Spontaneous Microstructure Formation at Water/Paraffin Oil Interfaces

et al. 2017

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“…The definition is ambiguous because it is not clear whether they are thermodynamically stable microemulsions or kinetically stable macroemulsions. Some researchers relate the formation of microdispersion to the spontaneous emulsification process because ultra-low IFT or mechanical agitation is not required for this process [44][45][46][47][48][49] . Several mechanisms, including interfacial turbulence and diffusion, have been proposed to explain the spontaneous emulsification in high IFT systems (a few mN/m) 46,49 .…”

Section: Correlation Between Wettability Alteration and The Microdispmentioning

confidence: 99%

Evaluating physicochemical properties of crude oil as indicators of low-salinity–induced wettability alteration in carbonate minerals

Song

Rezaee

Guo

et al. 2020

Sci Rep

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the injection of low-salinity brine enhances oil recovery by altering the mineral wettability in carbonate reservoirs. However, the reported effectiveness of low-salinity water varies significantly in the literature, and the underlying mechanism of wettability alteration is controversial. In this work, we investigate the relationships between characteristics of crude oils and the oils' response to low-salinity water in a spontaneous imbibition test, aiming (1) to identify suitable indicators of the effectiveness of low-salinity water and (2) to evaluate possible mechanisms of low-salinity-induced wettability alteration, including rock/oil charge repulsion and microdispersion formation. Seven oils are tested by spontaneous imbibition and fully characterized in terms of their acidity, zeta potential, interfacial tension, microdispersion propensity, water-soluble organics content and saturate-aromatic-resinasphaltene fractionation. For the first time, the effectiveness of low-salinity water is found to positively correlate with the oil interfacial tension in low-salinity water. Oils with higher interfacial activity are found to respond more positively to low-salinity water. Moreover, cryogenic transmission electron microscopy images suggest that microdispersion is essentially macroemulsion, and its formation is an effective indicator-but not the root cause-of wettability alteration. The repulsive zeta potential for the rock and the oil in low-salinity water is found to be an insufficient condition for wettability alteration in carbonate minerals.

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“…44 Similar phenomena have been recently observed for other oil-soluble surfactants across W/O interfaces. 40,45 This phenomenon is associated with a drastic decrease in g, compensating for the increase in surface area associated with droplet formation, which favours negative Gibbs free energy values leading to spontaneous droplet formation. 44 It is possible, qualitatively, to relate both g and |G i *| to the particle volume fractions at the interface (f i ) as g p 1/f i and, |G i *| p f i .…”

Section: Soft Matter Papermentioning

confidence: 99%