US Patent 7629299 Process for recovering residual oil employing alcohol ether sulfonates

A method of recovering crude oil from a subterranean hydrocarbon containing formation which comprises (a) injecting into said formation an aqueous solution containing an effective amount alkali metal, alkaline-earth or ammonium salts of alcohol ether sulfonates derived from unsaturated alcohol ethers, and (b) displacing said solution into one or more injection wells and recovering the oil from one or more production wells. The unsaturated alkoxylated alcohol contain various amounts of ethylene oxide, propylene oxide and butylene oxides elected to optimize their interfacial properties with different types of crude oil with different brines.