| abstract |
A surfactant for use in secondary and, more preferably, tertiary oil recovery operations, comprising a salt of at least one mono-, di- or tri-alkyl, 1,2-dimethylbenzene sulphonic acid. The alkyl group(s) is or are each C6 , preferably C9 to C15, most preferably about C10 to C13, the monoalkyl 1,2-dimethylbenzene sulphonate salts being preferred. The sulphonate salts may be derived from mixtures of sulphonic acids having different chain lengths of alkyl group. Although any water soluble sulphonate of the foregoing type has excellent surfactant properties for secondary and tertiary oil recovery, the preferred cations are derived from diethanolamine and triethanolamine. |