초록 ▼

An aqueous solution containing a water soluble polymer and a nonalkaline aqueous solution containing a polyvalent cation are sequentially injected into the relatively highly permeable zones of a subterranean formation. The solutions preferentially enter the relatively highly permeable zones and form

An aqueous solution containing a water soluble polymer and a nonalkaline aqueous solution containing a polyvalent cation are sequentially injected into the relatively highly permeable zones of a subterranean formation. The solutions preferentially enter the relatively highly permeable zones and form a flocculate in situ when the polymer and cation contact and mix in the connate water. Sequential injection may be repeated several times until the permeability of the relatively highly permeable zones is substantially reduced thereby improving conformance in the subterranean formation.

대표청구항 ▼

A process for reducing permeability in at least one relatively highly permeable zone of a subterranean formation also containing at least one relatively less permeable zone, said formation penetrated by a well in fluid communication therewith, the process comprising the sequential steps of: (a) inje

A process for reducing permeability in at least one relatively highly permeable zone of a subterranean formation also containing at least one relatively less permeable zone, said formation penetrated by a well in fluid communication therewith, the process comprising the sequential steps of: (a) injecting an aqueous solution containing a high molecular weight, water soluble, organic polymer into said at least one relatively highly permeable zone via said well whereby said polymer substantially penetrates said at least one relatively highly permeable zone; and (b) injecting via said well a slightly acidic aqueous solution containing a polyvalent cation in at least a stoichiometric amount relative to the reactive groups of said polymer into said at least one relatively highly permeable zone penetrated by said polymer wherein said cation contacts said polymer to produce a flocculate in situ, which substantially reduces the permeability of said at least one relatively highly permeable zone.