Plugging of water-producing zones in a subterranean formation

摘要

A method of selectively plugging permeable water-producing zones in a subterranean formation of nonuniform permeability comprising sequentially injecting into the formation (1) an aqueous solution of a first reactant material rendered more viscous than the subsequently injected liquids by the addition of a viscosity increasing agent, (2) a low viscosity inert aqueous spacer liquid, (3) a low viscosity aqueous solution containing a second reactant material which, on contact, will react with the first reactant material to produce an insoluble precipitate, (4) a low viscosity inert aqueous spacer liquid and (5) an additional amount of the aqueous solution of a first reactant material, which aqueous solution is optionally rendered more viscous than the previously injected aqueous solution containing the second reactant material by the addition thereto of a viscosity increasing agent.