Compositions for enhanced oil recovery

Abstract

Compositions and methods for increasing recovery, or flowback, of hydrocarbon compounds from hydrocarbon-containing subterranean oil formations. Concentrates include a sulfonated and/or a sulfated surfactant, an alkoxylated alcohol surfactant, a coupling agent, a hydrotrope, an additional surfactant, and water. Injectate compositions for oil recovery include the concentrate and a water source such as a produced water and/or seawater. Inclusion of particular hydrotropes such as sodium xylene sulfonate and/or potassium toluene phosphate in the compositions provides higher yields of hydrocarbons recovered. Larger amounts of hydrotrope result in an increase in injectate interfacial tension, but also result, as judged by decreased turbidity, in improved compatibility of the surfactant system in injectates made with water sources comprising salts.

Dependencies are inferred from the claim text.