Visualising surfactant enhanced oil recovery

- Surfactant EOR followed in 2D and 3D porous media by microscopy and NMR.
- Adding surfactant in “L1-based” formulations reduces γ and enhances recovery.
- L3-based formulations give ultra-low interfacial tensions and better recovery.
- L3-based floods show two saturation fronts and surfactant hold-up.
- L3-based floods consistent with formation then displacement of microemulsion phases.