Process for improving vertical conformance in a near well bore environment

Claim 1

A process for substantially plugging at least one zone of relatively high permeability in a near well bore environment of a subterranean formation penetrated by a well bore in fluid communication therewith, said formation having said at least one zone of relatively high permeability and at least one zone of relatively low permeability, the process comprising the steps of: (a) injecting an aqueous solution containing an organic polymer capable of being cross linked by a cross-linking agent into said near well bore environment via said well bore; (b) injecting a hydrocarbon spacer between said solution containing said polymer and an aqueous solution containing said cross-linking agent into said near well bore environment via said well bore in an amount sufficient to delay mixing of said solutions containing said polymer and said cross-linking agent until said solutions are in said near well bore environment; (c) injecting said solution containing said cross-linking agent into said near well bore environment via said well bore; and (d) reacting said polymer and said cross-linking agent upon said mixing to form a gel preferentially and predominantly within said at least one zone of relatively high permeability in said near well bore environment, which substantially plugs said at least one zone of relatively high permeability in said near well bore environment.