Patent ID: 6939832

Claim:
A method of treating a subterranean formation, the method comprising: (A) injecting down a well bore into the formation an admixture of (a) an emulsion having an internal aqueous phase comprising a water-soluble oil or gas field chemical or an aqueous dispersion of a water-dispersible oil or gas field chemical and an external oil phase comprising a liquid hydrocarbon and an oil-soluble surfactant and (b) a demulsifier comprising a solution of a surfactant having a cloud point temperature of above 40° C.; or (B) separately injecting down a well bore into the formation emulsion (a) and demulsifier (b) and generating an admixture of emulsion (a) and demulsifier (b) within the formation, wherein the demulsifier comprises at least one surfactant selected from the group consisting of: (a) polyamine salts such as polyester amines, amino methylated poly acrylamide, poly di-methyl amino propyl methacrylamide, poly dimethyl amino ethyl acrylate, poly ethylene imine, poly vinyl pyrrolidone, caprolactam-based polymers and quaternised version thereof (b) multifunctional polyethers such as sulfated triglycerides; (c) polyethers, such as copolymers of ethylene oxide and propylene oxide and the reaction products of such copolymers with diacids, diepoxides, diisocyanates, aldehydes, and diamines; and (d) p-alkylphenol-formaldehyde resins and the ethylene oxide and/or propylene oxide derivatives thereof.