| 摘要 |
A conformance improvement treatment process is provided for reducing the permeability of a higher-permeability zone in a subterranean hydrocarbon-bearing formation which is in fluid communication with a lower-permeability zone of the formation. The process includes preparing a gel precursor solution at the surface, injecting the solution into a wellbore penetrating the formation, placing the solution in the higher-permeability zone and gelling the solution therein. In situ gelation of the solution results in substantial permeability reduction to the higher-permeability zone. A specific gel precursor solution is utilized which contains a gelling agent and a polymer formed from at least two distinct monomers wherein the first monomer has a relatively faster, yet controlled, rate of hydrolysis and the second monomer has a relatively slower rate of hydrolysis. Gelation of the solution is delayed until a substantial number of carboxylate groups are formed in situ on the polymer. The gelling agent subsequently reacts with the carboxylate groups to effect gelation of the solution.
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