A preferred novel breaker-crosslinker-polymer complex and a method for using the complex in a fracturing fluid to fracture a subterranean formation that surrounds a well bore by pumping the fluid to a desired location within the well bore under sufficient pressure to fracture the surrounding subterranean formation. The complex may be maintained in a substantially non-reactive state by maintaining specific conditions of pH and temperature, until a time at which the fluid is in place in the well bore and the desired fracture is completed. Once the fracture is completed, the specific conditions at which the complex is inactive are no longer maintained. When the conditions change sufficiently, the complex becomes active and the breaker begins to catalyze polymer degradation causing the fracturing fluid to become sufficiently fluid to be pumped from the subterranean formation to the well surface.
Methods of treating subterranean zones and viscous aqueous fluids containing xanthan biopolymer gelling agent and a combination crosslinker and delayed breaker are provided. A viscous cross-linked aqueous treating fluid of the invention comprises water, a xanthan polymer gelling agent, and a combination cross-linker and delayed breaker for said xanthan biopolymer gelling agent.
Metal complexes of titanium and zirconium with N,N-bis(2-hydroxyethyl)glycine are provided, and more particularly to an improved process to prepare the titanium and zirconium complexes of N,N-bis(2-hydroxyethyl)glycine. Such complexes are used in oil well fracturing and plugging applications.
