Preparation and performance of graphene oxide-polyacrylamide based nanoscale microsphere emulsion for profile control

A new kind of in-depth profile control and displacement graphene oxide-polyacrylamide (GO-PAM) based nanoscale microsphere emulsion for enhancing oil recovery was designed by the inverse microemulsion polymerization technology, which simultaneously plays the multifunction roles of plugging pore throat, reducing water-oil interfacial tension and oil viscosity benefiting from the synergistic effect of nanoscale microsphere and GO sheets. The emulsion shows superior suspension properties, thermal stability, hydration swelling, and the excellent emulsifying ability for crude oil. The average particle size of PAM microspheres is about 40 nm, and the size of GO sheets is about 1–10 µm. Only 0.1% dispersion of GO-PAM emulsion reduces the water-oil interfacial tension by 63%, and reduces the viscosity of thick oil by 10%. And with increasing emulsion dosage to 5%, the viscosity can be reduced by more than 50%. For low permeability simulated cores, the plugging efficiency of the GO-PAM emulsion system increases from 80% to 88% compared with PAM emulsion. The microscopic oil displacement experiment shows that our designed emulsion enhanced oil recovery by 6–7%. The GO-PAM composite microsphere emulsion is expected to be a competitive candidate for in-depth profile control and heavy crude recovery.