Increase of the effectiveness of the flooding in the case of the obtaining oil

摘要

A dual surfactant system usable in the presence of from about 200 to about 18,000 parts per million polyvalent ions, such as calcium and/or magnesium, and a method of using said surfactant system for recovering petroleum from subterranean formations, said surfactant system comprising water soluble salts of alkyl or alkylaryl sulfonates wherein the alkyl chain may have from five to 25 carbon atoms, plus sulfated oxyalkylated surfactants containing arylalkyl groups.