Effect of Capillary Number on the Residual Saturation of Colloidal Dispersions Stabilized by a Zwitterionic Surfactant

We investigated oil recovery from porous rock using nanoscale colloidal dispersions, formed by adsorption of an anionic polymer [poly-(4styrenesulfonic acid-co-maleic acid); PSS-co-MA] and a zwitterionic surfactant [N-tetradecyl-N, N-dimethyl-3-ammonio-1-propanesulfonate, TPS] onto silica nanoparticles. In emulsion, dispersion enhanced the stability oil-water interface in absence particle aggregation; hydrophobic alkyl chains TPS shifted into drop, not only physiochemically, stabilizing interface, but also promoting repulsive particle-to-particle interaction. Core flooding experiments on residual saturation as function capillary number, at various injection rates viscosities, showed that level was reduced almost half when present dispersion. Consequently, result revealed this provides mechanically robust layer without aggregation. Thus, readily entered pore throat adhered to lowering interfacial tension improving recovery.