Patent ID: 7114568

Claim:
A method of reducing the water permeability of a well bore in a formation, comprising: introducing into the wellbore a treating fluid for separating a first fluid from a second fluid and for displacing the first fluid from the wellbore in advance of the second fluid, the treating fluid comprising a water soluble relative permeability modifier, wherein the water soluble relative permeability modifier comprises a hydrophobically modified water soluble polymer, the hydrophobically modified water soluble polymer being a reaction product of a hydrophilic reactive polymer and a hydrophobic compound, wherein the hydrophobic compound comprises an alkyl halide; and allowing the treating fluid to enter the formation, thereby allowing the water soluble relative permeability modifier to be adsorbed into the formation, which adsorption causes a reduction in the water permeability of the wellbore without substantially reducing the hydrocarbon permeability thereof.