George W Lester

US Patent:

44118023, Oct 25, 1983

Filed:

Sep 8, 1981

Appl. No.:

6/299708

Inventors:

George W. Lester - Hoffman Estates IL
Thomas P. Malloy - Lake Zurich IL

Assignee:

UOP Inc. - Des Plaines IL

International Classification:

E21B 4322

US Classification:

252 855D

Abstract:

The recovery of residual oil which is found in subterranean reservoirs may be accomplished by utilizing an aqueous surfactant slug to reduce the interfacial tension between the oil and water. A surfactant slug which may be used will comprise a mixture of a neutralized sulfonate derivative from powdered coal, a lower alkyl alcohol which possesses from about 3 to about 6 carbon atoms and a non-ionic surfactant comprising an ethoxylated n-alcohol possessing from about 12 to about 15 carbon atoms. The surfactant slug will possess relatively low interfacial tension which may be in the range of from below 10. sup. -3 dynes per cm.