Oil displacement enhanced by lyothropic liquid crystals in highly saline media

Abstract From the Canadian patent

An improved process is disclosed for recovering oil from an oil-bearing formation by injecting into the formation a liquid containing an effective amount of a surfactant to displace oil driving the liquid through the formation and recovering the displaced oil, the improvement comprising using as the liquid a lamellar lyotropic liquid crystal which exhibits decreasing viscosities at increasing shear rates and contains, (a) 0.05 to 10 vol.% of surfactant of balanced hydrophilic-lipophilic character, (b) 0.1 to 20 vol.% of an oil and, (c) the balance brine containing from 5 to 30 wt.% of inorganic salts having sodium chloride as the major component and salts of divalent metals as minor …