Abstract: A process for decreasing the water permeability of a subterranean rock formation is disclosed. The process involves the use of a water-soluble polymer in conjunction with an aluminum citrate preparation. The polymer can be injected into the formation first, followed by injection of the aluminum citrate preparation. Alternatively, an aqueous solution comprising both the polymer and the aluminum citrate preparation can be injected into the subterranean formation. Yet another process includes mixing a dry composition comprising the polymer and the aluminum citrate preparation, then dissolving this mixture in an aqueous solution which is then injected into the rock formation.

Abstract: A method and use for a dry composition comprising a mixture of water-soluble polymer and an aluminum citrate preparation is disclosed. The polymer is capable of cross-linking in the presence of water and aluminum ions. Any water-soluble polymer known to the art is suitable. Cross-linked polymer forms a gel in highly permeable, watered-out regions of oil-containing rock, allowing for increased oil recovery and decreased water use and recycling.

Abstract: A method for the preparation, drying and use of a stable aluminum citrate solution is disclosed. The method involves first mixing a solution containing an aluminum-chloride compound having a molar ratio of aluminum to chloride greater than about 1:3 with an aqueous solution comprising citrate. This "starter" solution is agitated at a sufficient rate to keep the slurry moving while the pH of the mixture is adjusted to a level of about 5.0 to about 9.0. The final aluminum citrate product is used to crosslink water-soluble polymer in solution for the purpose of restricting water flow in subterranean formations. The resultant aluminum citrate solution may be used either as a liquid or dried prior to shipping and using at a remote location.