Process to prepare borozirconate solution and use as a cross-linker in hydraulic fracturing fluids
AssigneeE.I. du Pont de Nemours and Company
InventorDonald Edward Putzig
Life of this patent
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Abstract
A process to prepare a stable solution of a borozirconate complex is disclosed and use of the solution in oil field applications such as hydraulic fracturing and plugging of permeable zones. The process comprises contacting zirconium complex with alkanolamine, then water and optionally and preferably a hydroxyalkylene diamine, then with a boron compound. The solution is particularly suitable for use in a cross-linking composition in hydraulic fracturing and plugging of permeable zones of subterranean formations at temperatures of 275° F. (135° C.) and higher in the formation.
Claims23
A process for preparing a solution of a borozirconate complex suitable for cross-linking in a fracturing fluid comprises:
- (a) contacting a zirconium complex with an alkanolamine at a ratio of 2 to 10 moles of the alkanolamine per mole of zirconium to form a first mixture;
- (b) contacting the first mixture with water at a ratio of about 2 to 10 moles of water per mole of zirconium and with 0 to 2 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with 1 to 4 moles of a boron compound per mole of zirconium in an alcohol at a temperature of 25° C. to 90° C. for a period of time sufficient to stabilize the resulting borozirconate solution.
A cross-linking composition which comprises an aqueous liquid;
- a pH buffer;
- a cross-linkable organic polymer;
- and a borozirconate solution prepared by a process which (a) contacting a zirconium complex with an alkanolamine at a ratio of 2 to 10 moles of the alkanolamine per mole of zirconium to form a first mixture;
- (b) contacting the first mixture with water at a ratio of about 2 to 10 moles of water per mole of zirconium and with 0 to 2 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with 1 to 4 moles of a boron compound per mole of zirconium in an alcohol at a temperature of 25° C. to 90° C. for a period of time sufficient to stabilize the resulting borozirconate solution.
A method for hydraulically fracturing a subterranean formation, which comprises introducing into the formation at a flow rate and pressure sufficient to create, reopen, and/or extend one or more fractures in the formation, a cross-linking composition comprising an aqueous liquid;
- a pH buffer;
- a cross-linkable organic polymer, and a solution of a borozirconate complex wherein the solution is prepared by a process comprising (a) contacting a zirconium complex with an alkanolamine at a ratio of 2 to 10 moles of the alkanolamine per mole of zirconium to form a first mixture;
- (b) contacting the first mixture with water at a ratio of about 2 to 10 moles of water per mole of zirconium and with 0 to 2 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with 1 to 4 moles of a boron compound per mole of zirconium in an alcohol at a temperature of 25° C. to 90° C. for a period of time sufficient to stabilize the resulting borozirconate solution.
A method for selectively plugging permeable zones and leaks in subterranean formations which comprises introducing into the permeable zone or the site of the subterranean leak, a cross-linking composition comprising an aqueous liquid;
- a pH buffer, a cross-linkable organic polymer;
- and an aqueous solution of the borozirconate complex comprising an aqueous liquid;
- a pH buffer;
- a cross-linkable organic polymer, and a solution of a borozirconate complex wherein the solution is prepared by a process comprising (a) contacting a zirconium complex with an alkanolamine at a ratio of 2 to 10 moles of the alkanolamine per mole of zirconium to form a first mixture;
- (b) contacting the first mixture with water at a ratio of about 2 to 10 moles of water per mole of zirconium and with 0.1 to 2 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with 1 to 4 moles of a boron compound per mole of zirconium in an alcohol at a temperature of 25° C. to 90° C. for a period of time sufficient to stabilize the resulting borozirconate solution.
Dependencies are inferred from the claim text.