Selective permeability reduction with polymerizable monomers around steam injection wells

A method is proposed for treating subsurface earth formations in the neighborhood of a steam injection well by selectively altering the effective permeability of the formation through depositing a monomer within the formation where the permeability is to be controlled and the eventual polymerization of that monomer to produce a high-viscosity polymer within the formation to effectively decrease the permeability of that portion of the formation. The monomer is transported to the subsurface formation in vapor form with steam. The mixed vapor first condenses out liquid water only and later condenses out water and immiscible liquid monomer. The polymerization of the monomer then takes place to produce a high-viscosity polymer within the subsurface formation.