Correlation of weighted effect of different ions and surfactant composition for surfactant flood

Abstract From the Canadian patent

Abstract of the Disclosure, In the recovery of oil from a formation with an aqueous surfactant solution containing an anionic surfactant such as a petroleum sulfonate a, cosurfactant such as tertiary butyl alcohol and an electrolyte, a specific, surfactant system which is suitable for the given formation is selected by:, (1) analysing the formation brine and determining the total effective Na + concentration, on the basis that each part Ca++ is equivalent to about 14 parts Na+ and each part Mg++ is equivalent to about 16 parts Na+; (2) comparing this total effective Na+ concentration with previously prepared phasevolume diagrams of surfactant systems partitioning into separate phases as a …