A critical review of development and demulsification mechanisms of crude oil emulsion in the petroleum industry

Abstract

The need for efficient demulsification process to treat emulsions in the petroleum industry is well acknowledged. For decades, numerous researches have been conducted to examine mechanisms of emulsification and demulsification. Untreated emulsion has both technical and commercial implications in the industry, especially in terms of treatment facilities, refining and transportation. Effective treatment is needed to ensure optimum production of hydrocarbons. The present paper is to review reported works on the formation of petroleum emulsions, demulsification treatments, characteristics of fit-for-purpose demulsifiers as well as research trends in emulsion treatment. Crude oils are naturally combined with natural surfactants having high tendency to form stable emulsion. The stable emulsion must be treated well to meet industrial requirements since crudes with a high volume of stable emulsion have a less value. Therefore, fundamental studies on natural surfactants, which contribute to the emulsion stability, are analyzed for the effective separation of emulsions into oil and water. This would involve the assessment of various reported mechanisms for the emulsification and right formulation for effective demulsification.

Applying ultrasonic fields to separate water contained in medium-gravity crude oil emulsions and determining crude oil adhesion coefficients

“…Demulsifying crude oils can be achieved in laboratory and field scales [15] , [16] by various processes, which in addition to dosing them with chemical demulsifiers, include treatments involving: centrifuges [17] , filtration through membranes [18] , and microwave irradiation [19] , [20] . These demulsification procedures demonstrate high efficiency when applied to light crude oils.…”

Application of Ionic Liquids for Chemical Demulsification: A Review

“…Emulsion is produced when two or more immiscible liquids mix vigorously together which results in two phases (a dispersed phase and a continuous phase) [ 25 , 26 ]. The phase that has smaller volume is usually identified as the dispersed phase and the larger one is the continuous phase.…”

“…In general, stable W/O emulsions can hold most of the water in the oil phase for more than five days [ 43 ]. Mesostable emulsions are stable within only one to three days, while entrained water and unstable W/O emulsions are not regarded as stable emulsions because both would only remain water in oil for less than one day [ 26 , 42 ]. Emulsion type is an important factor in selecting demulsifiers which are soluble in the continuous phase and could reach the O-W interface easily [ 36 ].…”

Optimization of non-ionic surfactants for removing emulsified oil from gas condensate oil–water emulsion in N oilfield

“…The first two kinds of oil were removed in DAF progress without any chemicals. The removal of dissolved oil is difficult, and the commonly used methods are membrane separation method, adsorption method and biological method (Qiang 2012). It can be seen from Table 3 that the solubility of these four compounds in water is greater than that of normal alkanes with the same number of carbon atoms.…”