A method for enhancing recovery of oil from an oil-bearing carbonate formation within a reservoir. The method has the steps of (a) introducing a viscous gel under pressure into the oil-bearing carbonate formation and (b) extracting oil. The aqueous viscous gel has water and an amount of a non-polymeric viscosifying surfactant sufficient to provide the flooding fluid with an oil/water interfacial surface tension of about 10 mN/m or less and a viscosity of about 10 cP or more of the one or more non-polymeric surfactants. The one or more non-polymeric, viscosifying surfactants is selected from the group of one or more cationic surfactants, one or more zwitterionic surfactants, one or more anionic surfactants, one or more amphoteric surfactants, and combinations thereof. In a preferred embodiment, the aqueous viscous gel is also substantially free of solids.