Advances of Spontaneous Emulsification and its Important Applications in Enhanced Oil Recovery Process


Emulsions, including oil-in-water (O/W) and water-in-oil (W/O) emulsions, can play important roles in both controlling reservoir conformance and displacing residual oil for enhanced oil recovery (EOR) projects. However, current methods, like high-shear mixing, high-pressure homogenizing, sonicators and others, often use lots of extra energy to prepare the emulsions with high costs but very low energy efficiency. In recent decades, spontaneous emulsification methods, which allow one to create micro- and nano-droplets with very low or even no mechanical energy input, have been launched as an overall less expensive and more efficient alternatives to current high extra energy methods. Herein, we primarily review the basic concepts on spontaneous emulsification, including mechanisms, methods and influenced parameters, which are relevant for fundamental applications for industrials. The spontaneity of the emulsification process is influenced by the following variables: surfactant structure, concentration and initial location, oil phase composition, addition of co-surfactant and non-aqueous solvent, as well as salinity and temperature. Then, we focus on the description of importance for emulsions in EOR processes from advances and categories to improving oil recovery mechanisms, including both sweep efficiency and displacement efficiency aspects. Finally, we systematically address the applications and outlooks based on the use of spontaneous emulsification in the practical oil reservoirs for EOR processes, in which conventional, heavy, high-temperature, high-salinity and low-permeability oil reservoirs, as well as wastewater treatments after EOR processes are involved.


Geosciences and Geological and Petroleum Engineering

Research Center/Lab(s)

Center for Research in Energy and Environment (CREE)


This study was financially supported by the National Science and Technology Major Project (No. 2017ZX05009-004 ), the National Natural Science Foundation of China (No. 51774309 ), the Beijing Natural Science Foundation (No. 2204092 ), Beijing Municipal Excellent Talent Foundation.

Keywords and Phrases

Displacement and sweep efficiencies; Enhanced oil recovery (EOR); Low extra energy; O/W and W/O emulsions; Oil reservoirs; Spontaneous emulsification

International Standard Serial Number (ISSN)

0001-8686; 1095-7103

Document Type

Article - Journal

Document Version


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© 2020 Elsevier B.V., All rights reserved.

Publication Date

01 Mar 2020