Patent ID: 8403050

Claim:
A method of treating a hydrocarbon-bearing clastic formation having brine, the method comprising: contacting the hydrocarbon-bearing clastic formation with a fluid, wherein the fluid at least one of at least partially solubilizes or at least partially displaces the brine in the hydrocarbon-bearing clastic formation; and subsequently contacting the hydrocarbon-bearing clastic formation with a composition, the composition comprising: a nonionic fluorinated polymeric surfactant comprising: at least one divalent unit represented by formula: and a poly(alkyleneoxy) segment; wherein R f represents a perfluoroalkyl group having from 1 to 8 carbon atoms; R and R 2 are each independently hydrogen or alkyl of 1 to 4 carbon atoms; and n is an integer from 2 to 10; and solvent, wherein when the composition is contacting the hydrocarbon-bearing clastic formation, the nonionic fluorinated polymeric surfactant has a cloud point that is above the temperature of the hydrocarbon-bearing clastic formation.