Patent ID: 6972274

Claim:
A method for improving the water injectivity of an injection well in a petroleum containing formation by restoring the permeability of said petroleum-containing formation thereby enhancing the recovery of oil by the waterflood process, said method comprising treating said formation with a composition which comprises at least one nonionic surfactant and at least one cationic surfactant in an amount and a concentration effective to improve the permeability of said formation, wherein said at least one nonionic surfactant is selected from the group consisting of alkanolamides, alkoxylated alcohols, alkoxylated amines, alkyl phenyl polyethoxylates, lecithin, hydroxylated lecithin, fatty acid esters, glycerol esters and their ethoxylates, glycol esters and their ethoxylates, esters of propylene glycol, sorbitan, ethoxylated sorbitan polyglycosides and mixtures thereof, and said at least one cationic surfactant is an ethoxylated quaternary ammonium compound.