Characterization of Complex Crude Oil Microemulsions-DSC Contribution

Surfactant flooding is a chemical enhanced oil recovery (EOR) process which consists in injecting optimized formulations of surfactants in the reservoir in order to remobilize the residual oil trapped in the pores of the rock. To do that, it is necessary to design specific formulations in order to get so-called Winsor III systems of very low interfacial tensions with the crude oil. Unfortunately, there is no well-established way to characterize and understand the physical properties and structures of microemulsions composed of crude oil and industrial surfactants due to their extreme complexity. In a previous work, we have developed a methodology based on the use of several techniques (DLS, MLS, SAXS, cryo-SEM, DSC, interfacial measurements, etc.) allowing physico-chemical and morphological characterization of these microemulsions in the case of a model system. In this article, we will demonstrate how DSC can be used to provide information on the physico-chemical composition of complex microemulsions (water and oil content, salinity, etc.) and on their morphology (continuous phase, dispersed phase, etc.)