Demulsification of Asphaltene-Stabilized Emulsions—Correlations of Demulsifier Performance with Crude Oil Composition

Abstract

Model asphaltene-stabilized emulsions are used to study the impact of oil composition on the efficiency of demulsification. Varying ratios of toluene and heptane, mixed with asphaltene extracted from a Gulf of Mexico crude oil, were mixed with water to produce emulsions that exhibited characteristic coalescence (water drop) rates. Commercial demulsifiers of varying types and chemistries were added to these emulsions, and resultant rates of water drop measured and compared. Emulsion stability and demulsifier effectiveness are shown to be highly dependent on overall aromaticity of the crude as measured by hydrogen-to-carbon molar ratio. Correlations of observed behavior with actual crude emulsions and demulsifier performance were observed and are reported.

Acknowledgments

The authors would like to acknowledge Arif Shaikh of Baker Petrolite for analytical contributions and helpful discussions. They would also like to thank Dr. John Walsh and Dr. Sheila Dubey of Shell Oil for many helpful discussions.