Surfactant blends for aqueous solutions useful for improving oil recovery

Abstract

The present invention relates to an aqueous fluid useful for the recovery of a liquid hydrocarbon from subterranean reservoirs comprising an aqueous media and a surfactant blend. The aqueous fluid has an alkaline pH. The surfactant blend comprises at least one synthetic polyisobutylene surfactant and at least one secondary surfactant selected from the group consisting of sulfonate surfactants, alcohols and nonionic surfactants. The surfactant blend lowers the interfacial tension between hydrocarbon oil and the aqueous fluid.

1 - 17 . (canceled)  
     
     
         18 . A method of recovering oil from a subterranean reservoir penetrated by a well bore by: 
 a) providing an aqueous fluid into said reservoir said fluid comprising at least one polyisobutylene sulfonate surfactant; and    b) contacting said oil with said aqueous fluid;    whereby the interfacial tension between said aqueous fluid and said oil is effectively lowered.    
     
     
         19 . The method of  claim 18  wherein said surfactant blend further comprises at least one surfactant selected from the group consisting of sulfonate surfactants, alcohols, nonionic surfactants, and mixtures thereof.  
     
     
         20 . The method of  claim 18  wherein said aqueous fluid further comprises at least one alkaline material.  
     
     
         21 . The method of  claim 18  wherein said aqueous fluid further comprises at least one water soluble polymeric thickener.  
     
     
         22 . The method of  claim 18  wherein said alkaline material is selected form the group consisting of sodium hydroxide, sodium carbonate, sodium bicarbonate, sodium sulfate and mixtures thereof.  
     
     
         23 . The method of  claim 18  wherein said tertiary oil recovery is 10% or more of the original oil in place.