The effect of inorganic solids on emulsion layer growth in asphaltene‐stabilized water‐in‐oil emulsions

Abstract

Oilfield emulsions are often stabilized by asphaltenes but inorganic solids can impact both emulsion stability and rag layer accumulation. In this study, the effect of inorganic solids on emulsion stability and emulsion layer growth was investigated using batch and continuous separations performed on water‐in‐oil emulsions stabilized by asphaltenes. The emulsions were prepared at 60 °C from an organic phase consisting of solids, asphaltenes, n‐heptane, and toluene and an initial water phase volume of 0.50. Three types of coarse solids were considered: 12 μm kaolin, 18–32 μm silica, and 32–63 μm silica with wettabilities ranging from 50 to 125°. In batch experiments, the coalescence rate was determined from the change in height of the free water and oil layers over time as the emulsion coalesced. In continuous experiments, emulsion layer growth was measured as the emulsion was continuously fed into a vertical separator. The data were modelled with a material balance that included a coalescence rate equation. In the absence of solids, the continuous emulsion layer growth rate and ultimate stability correlated well to batch coalescence parameters. The addition of the coarse solids at concentrations below 5 g/L accelerated coalescence rates. Above 5 g/L, the solids increased emulsion stability indicating that they form a steric barrier between the droplets. Even if the feed is below this threshold, the solids accumulate in the rag layer until the threshold is reached, the emulsion becomes stable, and the performance of the continuous separation can no longer be predicted from batch tests.

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

“…Application of seawater or low salinity water flooding increases the water–oil interactions and asphaltene engagement in the stability of water–asphaltenic oil interfacial characteristics. The presence of ions in the seawater is a natural stabilizing phenomenon that may introduce less use of chemicals. , Asphaltene molecules act as natural surface-active agents. They move toward and spread along with the interface of water and oil.…”

“…We have learned that it is essential to thoroughly study the interactions between the injected phase (brine) and oil at different salinity conditions. The emulsion stability depends on pressure, , temperature, , salinity, type of salt, ,, pH, , resin to asphaltene ratio, , and the presence of solids particles. , All the factors mentioned above are different from atmospheric conditions. Asphaltene’s behavior and interactions may significantly differ in reservoir conditions.…”

Switchable-Hydrophilicity Triethylamine: Formation and Synergistic Effects of Asphaltenes in Stabilizing Emulsions Droplets

“…The formation of emulsions during oil extraction makes the separation much more difficult [14,15]. However, little information has been reported on the exact mechanisms of SHS in stabilizing oil–water emulsions, especially its role together with natural interfacial active materials, such as asphaltenes [16,17,18,19,20,21,22].…”

Preface of the 66th Canadian Chemical Engineering Conference: “Sustainability and Prosperity”

“…This special issue section would have not materialized without the efforts of the contributing authors and the reviewers to ensure, despite their busy schedules, that all accepted papers meet the quality standards of The Canadian Journal of Chemical Engineering . The guest editors are also sincerely thankful to the Editor‐in‐Chief of The Canadian Journal of Chemical Engineering , Prof. João Soares, for his support and guidance, and to his editorial staff for their efforts, in welcoming this series of papers on timely topics.…”