Control of crosslinking reaction rate using organozirconate chelate

Abstract

An aqueous gel containing a crosslinking agent comprising an organozirconate chelate and a rate retarding agent which delays crosslinking of the gel or a rate accelerating agent which accelerates crosslinking of the gel. The retarding agent comprises a selected aldehyde or dialdehyde. The accelerating agent comprises a member selected from a group of polyamines. In the preferred embodiment, the crosslinking agent and crosslinking rate retarder or accelerator are injected simultaneously, yet independently, into an aqueous gel while introducing the gel into a subterranean formation sought to be fractured. The viscosity of the gel increases over a period of time which is controllable by altering the quantity of rate retarding agent or accelerating agent delivered in conjunction with a fixed concentration of crosslinking agent.