In this paper, we present a new route to mitigate surfactant retention in chemical EOR projects. Surfactants retention, either through adsorption on reservoir rocks or phase trapping, is one of the main constraints to achieve high performance and economical chemical EOR. Specific injection strategies thus need to be developed to mitigate surfactants retention. The use of alkaline and/or salinity gradient approaches present the disadvantage of being restricted to very specific conditions. For example, in hard brine environments, alkalis cannot be used because they can cause scaling. In an offshore environment, as sea water is the only injection water available, water treatment is required in order to use alkali or to perform a salinity gradient.

The new route to mitigate adsorption proposed in this paper is based on the use of specific, cost effective, chemical additives which allow mimicking the effect of salinity gradient. The resulting processes, when properly optimized, can achieve very high performances in terms of oil recovery with a limited amount of injected chemicals. Final performance, at lab scale, is comparable to the highly performing ASP/ SP processes in soft brines with salinity gradient.

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