Critical Review of Underlying Mechanisms of Interactions of Asphaltenes with Oil and Aqueous Phases in the Presence of Ions

Abstract

Asphaltene studies have been a prime focus topic for many decades. However, the underlying interaction mechanisms between water, oil, and asphaltenes requires more attention. Water is involved in all production parts (reservoir, tubing, surface facilities, and refinery), posing comprehensive research about the issues and operating conditions. According to the available literature, there are contradictory opinions regarding the effect of salinity on the aqueous phase and the oil phase interfacial characteristics. This review provides a critical summary of asphaltene’s role in the stability of the aqueous phase emulsions in an oil phase. We reviewed the effect of temperature, pressure, asphaltene concentration, bulk phase components, different salinity, types of ions, and pH on emulsion stability regarding the low salinity water injection aspects. Moreover, the studied cases investigating emulsion stability in the presence of asphaltenes and other species were collected, compared, and categorized. Furthermore, the interfacial and rheological characteristics of the brine–oil interface composed of asphaltenes and other species were compared. We found that the effect of some parameters requires an in-depth study as there are not many related works. For example, the effect of pressure on the rheological characteristics of emulsions and, at the same time, on the aggregation, precipitation, and deposition using visual devices (high pressure–high temperature microfluidic) is missing from the literature. Therefore, we recommend a specific study of each crude oil’s combined effects of temperature, pressure, and salinity. Low salinity water injection is a newly developed enhanced oil recovery method that employs the results of emulsion studies in the presence of different ions and reservoir conditions (high pressure and high temperature).