pH-Responsive Amphiphiles in Enhanced Oil Recovery

In this talk, a novel approach based on the complexation and supramolecular assembly of an amino-amide and maleic acid to control viscosity of aqueous displacement fluids will be described.  The addition of only 2 wt % of adaptable amphiphile/maleic acid into water increases the viscosity of water by 4.5x10⁵ times. This superior viscosity behavior is ascribed to the formation and entanglements of layered cylindrical supramolecular assemblies having diameters of several hundred nanometers. Furthermore, the viscosity of the amphiphile solution can be increased 12 times by changing pH from 4 to 8 in a reversible manner. Such a property can be very beneficial for oil recovery applications when the injectivity becomes a limitation. In addition, the use of switchable viscosity can reduce the energy cost associated with pumping large volumes of viscous displacement fluids.  We also demonstrate the proof-of-concept for the use of adaptable amphiphile solutions in EOR as oil displacement fluids through column experiments. Overall, this presentation describes that pH-switchable supramolecular assemblies have very intriguing properties that can significantly impact enhanced oil recovery technologies.