The method comprises injecting into an underground formation through an injection well about 0.05 to about 1.0 pore volumes of an aqueous surfactant slug comprising about 0.1% to about 10% by weight of {HEAD ~ a surfactant system}, injecting a drive fluid into {TAIL ~ the formation} through the injection well to push the surfactant slug towards the production well, and recovering hydrocarbons at the production well 
The method comprises injecting into an underground formation through an injection well about 0.05 to about 1.0 pore volumes of an aqueous surfactant slug comprising about 0.1 % to about 10 % by weight of { HEAD ~ a surfactant system } , injecting a drive fluid into { TAIL ~ the formation } through the injection well to push the surfactant slug towards the production well , and recovering hydrocarbons at the production well
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