The Role of Asphaltenes in Stabilizing Water-in-Crude Oil Emulsions

Sjöblom, Johan; Hemmingsen, Pål V.; Kallevik, Harald

doi:10.1007/0-387-68903-6_21

Cited by 57 publications

(52 citation statements)

References 107 publications

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“…Fine solids can also promote mechanical stabilization of emulsions. [3][4][5][6] The literature [7][8][9] shows that the molecular aggregates formed by asphaltenes, more so than the molecules in free form, help to stabilize W/O emulsions by forming a film or barrier at the interfaces.…”

Section: Introductionmentioning

confidence: 99%

The influence of asphaltenes subfractions on the stability of crude oil model emulsions

Honse¹,

Mansur²,

Lucas³

2012

J. Braz. Chem. Soc.

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O petróleo é produzido na forma de emulsão água em óleo e os asfaltenos são considerados os principais responsáveis pela estabilização dessas emulsões. O objetivo deste trabalho foi avaliar a influência de diferentes frações asfaltênicas sobre a estabilidade de emulsões modelo de petróleo (salmoura em asfaltenos/tolueno) e sobre a eficiência de desemulsificantes. A estabilidade das emulsões foi acompanhada pelo ensaio de garrafa, com e sem a adição de desemulsificante. Os resultados mostram que a amostra de asfaltenos com larga distribuição de polaridade promove maior estabilidade da emulsão do que a amostra com distribuição mais estreita e polaridade intermediária. Além disso, a eficiência do desemulsificante na separação das emulsões está diretamente relacionada à estabilidade original da emulsão. Resultados de tensão interfacial evidenciaram a eficiência de deslocamento dos asfaltenos pelos tensoativos desemulsificantes, o que ocorreu com maior eficiência para as emulsões contendo frações de asfaltenos com distribuição estreita e polaridade intermediária.Crude oil is produced as water-in-oil emulsion, and asphaltenes have been considered the main responsible by their stabilization. The aim of this work was to evaluate the influence of the asphaltenes subfractions on the stability of petroleum model emulsions and on the efficiency of demulsifiers. Model water-in-oil emulsions were prepared: aqueous phase of brine and oil phase of asphaltenes in toluene. Different asphaltenes fractions were used. The emulsions' stability was assessed by the bottle test, with and without adding demulsifier. The results show that a sample of asphaltenes with broad polarity distribution promotes greater emulsion stability than a sample with narrow distribution and intermediate polarity. Besides this, the efficiency of demulsifiers in separating the emulsions is directly related to the original stability of the emulsion. Measurements of the interfacial tension revealed the efficiency of displacement of the asphaltenes by the demulsifiers, which occurred more efficiently for the emulsions containing asphaltenes fractions with narrow distribution and intermediate polarity.

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Section: Introductionmentioning

confidence: 99%

The influence of asphaltenes subfractions on the stability of crude oil model emulsions

Honse¹,

Mansur²,

Lucas³

2012

J. Braz. Chem. Soc.

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“…[1][2][3][4][5][6] Due to the complex composition of crude oils, it is common to characterize each crude oil in terms the four SARA-fractions: saturates (S); aromatics (A); resins (R); asphaltenes (A). 7 The asphaltenes are defined as the crude oil fraction insoluble in high apolar light n-alkanes, such as n-pentane or n-heptane, and soluble in low polar solvents, such as benzene and toluene. The resins comprise the fraction soluble in n-pentane and n-heptane but insoluble in propane.…”

Section: Introductionmentioning

confidence: 99%

Effect of the structure of commercial poly(ethylene oxide-b-propylene oxide) demulsifier bases on the demulsification of water-in-crude oil emulsions: elucidation of the demulsification mechanism

et al. 2010

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Recebido em 29/10/09; aceito em 8/4/10; publicado na web em 24/8/10Water-in-crude oil emulsions are formed during petroleum production and asphaltenes play an important role in their stabilization. Demulsifiers are added to destabilize such emulsions,however the demulsification mechanism is not completely known. In this paper, the performances of commercial poly(ethylene oxide-b-propylene oxide) demulsifiers were studied using synthetic water-in-oil emulsions and model-systems (asphaltenes in organic solvent). No change in the asphaltene aggregate size induced by the demulsifier was observed. The demulsification performance decreased as the asphaltene aggregate size increased, so it can be suggested that the demulsification mechanism is correlated to the voids between the aggregates adsorbed on the water droplets surface.

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“…Despite the tremendous impact that water has on crude oil emulsions and the high costs associated to emulsion breaking, the stabilization mechanisms involved are not yet fully understood. The existing paradigm claims that w/o emulsions are almost exclusively stabilized by asphaltenes and hundreds of papers in scientific journals support this claim with experimental data; for review see e.g., [21][22][23][24] and the references therein. To elaborate on this a bit more, it is worth firstly reviewing in brief the natural surfactants presented in petroleum systems.…”

Section: Emulsions and Emulsion Films In Petroleum Systemsmentioning

confidence: 94%

“…Calcium and magnesium ions form water-insoluble salts when mixed with naphthenic acids often causing serious production problems, especially in offshore operations [24].…”

Section: Naphthenatesmentioning

confidence: 99%