Polymer Surfactant Interactions in Oil Enhanced Recovery Processes

A soil decontamination or enhanced oil recovery procedure typically requires the injection of a surfactant solution to reduce interfacial tension and promote oil recovery at the pore level, followed by the injection of a polymer solution to avoid the creation of preferential pathways and perform a homogeneous sweep of the reservoir. It is well known that polymers and surfactants interact with each other to form aggregates if they are of opposite charge or due to depletion interactions. To date, it is recommended to use polymers and surfactants that do not interact with each other to avoid clogging the wells. We show here that this precaution is not necessary and that in some cases, the use of interacting polymer and surfactant systems can even be an advantage for oil recovery. Contrary to previous studies, we injected previously mixed and homogeneous formulations into the porous medium and not a sequence of surfactant and polymer plugs. In addition to a total recovery of the oil in place, this strategy allows to limit the adsorption of the surfactant in the pore.

Automated summary

Traditionally, soil decontamination or enhanced oil recovery procedures involve injecting surfactants and polymers separately to avoid aggregation. Recent studies suggest that in some cases, using interacting polymer and surfactant systems can be more effective for oil recovery, contrary to previous beliefs.