Surfactant oil recovery method for use in high temperature formations containing water having high salinity and hardness

摘要

Disclosed is an aqueous surfactant fluid and an oil recovery method employing the fluid, the fluid containing at least two different surfactants: (1) An organic sulfonate anionic surfactant such as a petroleum sulfonate, or an alkyl or alkylaryl sulfonate, and (2) a dipolyalkoxylated, preferably dipolyethoxylated alkyl catechol, wherein the balance between the oil soluble alkyl group and water soluble ethoxy group is chosen to ensure effective capillary displacement at the formation temperature in water having a salinity about equal to the salinity of the formation water, and the total number of ethoxy groups is chosen so the cloud point of the ethoxylated alkyl catechol is from 2. degree. to 40 F. greater than the formation temperature.