Demulsification of Crude Oil Emulsions:  Correlation to Microemulsion Phase Behavior

Abstract

The search for the appropriate demulsifier for a water-in-crude oil emulsion is generally carried out through the well-known “bottle test” technique. A comprehensive approach is proposed here, which is based on earlier work on the rate of separation of surfactant−water−hydrocarbon mixtures, where it was found that “optimal” type III systems, in Winsor's nomenclature, exhibits the fastest separation rate. It is shown that the rules developed for microemulsion optimization apply to the selection of the demulsifier. They allow one to take into account the variation of salinity, temperature, crude-oil type, and so forth and provide an explanation for the demulsifier concentration effect. Interfacial tension measurements have been carried out. They show that the kinetics of demulsifier adsorption at the water−crude oil interface (or alternatively the Gibbs elasticity modulus) is correlated to the phase separation rate, as already described in the literature: the higher the kinetics, the faster the separation rate.

Ionic Liquids as Surfactants – Applications as Demulsifiers of Petroleum Emulsions

“…Therefore, water must be separated from crude oil before refining process [3]. There are several physical methods (thermal, mechanical, electrical and chemical) to break water/oil emulsions.…”

Brine-in-crude-oil emulsions at the Strategic Petroleum Reserve

“…Thompson et al (1985) of BP used emulsion bottle tests to examine at the effect of waxes on crude-oil emulsion stability. Goldszal and Bourrel (2000) of ELF France used emulsion bottle tests to optimize the amount emulsionbreaking compounds needed to breakup crude-oil emulsions. Fan et al (2009) of the Norwegian University of Science and Technology used bottle tests to examine the use of nonionic surfactants as emulsion-breaking compounds for treating crude-oil emulsions.…”

Surface Properties and Thermodynamic Parameters of Some Sugar‐Based Ethoxylated Amine Surfactants: 1—Synthesis, Characterization, and Demulsification Efficiency

“…The main advantages of using emulsion breakers are: rapidity and cost-effectiveness, reduction in the viscosity of crude oil emulsions, improved pump-ability, reduced oil waste handling, and reduction of the final disposal cost by a factor of 10 [25]. Therefore, different emulsion breakers are generally tested through a bottle test method, which consists of adding the given emulsion breaker to the sample of the emulsion and observing the percentage of water as a function of time [26]. The emulsion breaking process is presented in Fig.…”