Evaluation of surfactant blends for enhanced oil recovery through activity maps

Better use of already exploited oil reservoirs using Enhanced Oil Recovery techniques is becoming essen-tial. The use of surfactant blends is a common approach when individual surfactants are not effective. However, defining the optimum conditions for application becomes very challenging due to the number of variables involved in specific cases. In this work, blends of dioctyl sulfosuccinate sodium salt with Akypo LF2 and two surfactant ionic liquids (1-decyl-3-methylimidazolium chloride and 1-dodecyl-3-methylimidazolium bromide) were evaluated for oil recovery. Activity maps, representations of the phase behavior of the surfactants as a function of blend ratio, salinity and temperature, were found to be useful tools to describe conditions leading to Winsor type III systems. Among the blends studied, mixtures with Akypo LF2 were found of interest for application at low temperatures, showing interfacial tensions close to 0.01 mN/m in a wide range of salinity concentrations. In the case of blends with ionic liquids, even though they led to more promising solubilization parameters, the high sensitivity of these mixtures to blend ratio changes discourages, in principle, their use for practical applications.(c) 2022 The Authors. Published by Elsevier B.V. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/).

Automated summary

Better utilization of already developed oil reservoirs is crucial, and Enhanced Oil Recovery techniques play an important role in achieving this. Blending multiple surfactants is a common approach when individual surfactants are not effective, but determining the optimal conditions for application can be challenging due to numerous variables involved. This study evaluated blends of surfactants for oil recovery and found that activity maps were useful tools in describing conditions leading to Winsor type III systems.