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 a first alkanolamine, then water and optionally hydroxyalkylene diamine, then with a solution of a boron compound and a second alkanolamine. 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 use in a cross-linking composition which comprises:
- (a) contacting a zirconium complex with a first alkanolamine at a ratio of 2 to 10 moles of the first alkanolamine per mole of zirconium in an alcohol 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 1 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with a solution of a boron compound and a second alkanolamine in an alcohol, at a ratio of 1 to 4 moles of boron per mole of zirconium and 1 to 4 moles of the second alkanolamine per mole of boron and 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 comprises:
- (a) contacting a zirconium complex with a first alkanolamine at a ratio of 2 to 10 moles of the first alkanolamine per mole of zirconium in an alcohol 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 1 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with a solution of a boron compound and a second alkanolamine in an alcohol, at a ratio of 1 to 4 moles of boron per mole of zirconium and 1 to 4 moles of the second alkanolamine per mole of boron and 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 a first alkanolamine at a ratio of 2 to 10 moles of the first alkanolamine per mole of zirconium in an alcohol 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 1 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with a solution of a boron compound and a second alkanolamine in an alcohol, at a ratio of 1 to 4 moles of boron per mole of zirconium and 1 to 4 moles of the second alkanolamine per mole of boron and 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 a first alkanolamine at a ratio of 2 to 10 moles of the first alkanolamine per mole of zirconium in an alcohol 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 1 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture;
- (c) contacting the second mixture with a solution of a boron compound and a second alkanolamine in an alcohol, at a ratio of 1 to 4 moles of boron per mole of zirconium and 1 to 4 moles of the second alkanolamine per mole of boron and 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.