Method of extracting and reutilizing surfactants from emulsions with

Abstract

Disclosed is a method for extracting surfactants from produced emulsions of oil, water and surfactant and concentrating the surfactants into a relatively small volume, surfactant-rich, middle phase that can be reutilized in surfactant flooding. A first extraction is performed with an aqueous solution of a first extracting compound, which yields three phases after separation, a substantially water-free and surfactant-free crude oil phase, a first surfactant-rich middle phase and an oil-free aqueous phase. The first extracting compounds employed are the alkali metal salts and ammonium salts of cumene sulfonate, propyl benzene sulfonate, ethyl benzene sulfonate, methyl ethyl benzene sulfonate, diethyl benzene sulfonate, methyl propyl benzene sulfonate, xylene sulfonate and dicyclopentadiene sulfonate. A second extraction is then performed by mixing a second extracting compound with the first middle phase, which yields three phases after separation, a water-free and surfactant-free oil phase, a second surfactant-rich middle phase and an oil-free aqueous phase. The second extracting compound is a alkanol having two to four carbon atoms.