Lewis acid as gelation retarder for crosslinkable polymer compositions

A treatment fluid for a well including: (a) a water-soluble polymer, wherein the water-soluble polymer comprises a polymer of at least one non-acidic ethylenically unsaturated polar monomer; (b) an organic crosslinker comprising amine groups, wherein the organic crosslinker is capable of crosslinking the water-soluble polymer; (c) a Lewis acid; and (d) water; wherein the treatment fluid is a crosslinkable polymer composition. According to an embodiment, a method for blocking the permeability of a portion of a subterranean formation penetrated by a wellbore is provided, the method including the steps of: (a) selecting the portion of the subterranean formation to be treated; (b) selecting estimated treatment conditions, wherein the estimated treatment conditions comprise temperature over a treatment time; (c) forming the treatment fluid; and (d) injecting the treatment fluid through the wellbore into the portion of the subterranean formation.