Process to prepare zirconium-based cross-linker compositions and their use in oil field applications
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 solution of zirconium-alkanolamine-hydroxycarboxylic acid 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 an alcohol solution of a zirconium complex with an alkanolamine, then with an α-hydroxycarboxylic acid to produce a solution of zirconium-alkanolamine-hydroxycarboxylic acid complex. 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 zirconium complex suitable for cross-linking a fracturing fluid which comprises:
- (a) contacting an alcohol solution of a zirconium complex with an alkanolamine at a mole ratio of 2 to 4 moles of alkanolamine per mole of zirconium to form a mixture which is a solvent-based alkanolamine complex of zirconium;
- (b) contacting the mixture with an {tilde over (α)}-hydroxycarboxylic acid at a mole ratio of 2 to 4 moles of hydroxycarboxylic acid per mole of zirconium for a period of time sufficient to stabilize the resulting solution of zirconium-alkanolamine-hydroxycarboxylic acid complex.
A cross-linking composition which comprises an aqueous liquid;
- a pH buffer;
- a cross-linkable organic polymer;
- and a solution of zirconium-alkanolamine-hydroxycarboxylic acid complex prepared by a process which comprises:
- (a) contacting an alcohol solution of a zirconium complex with an alkanolamine at a mole ratio of 2 to 4 moles of alkanolamine per mole of zirconium to form a mixture which is a solvent-based alkanolamine complex of zirconium;
- (b) contacting the mixture with an {tilde over (α)}-hydroxycarboxylic acid at a mole ratio of 2 to 4 moles of hydroxycarboxylic acid per mole of zirconium for a period of time sufficient to stabilize the resulting solution of zirconium-alkanolamine-hydroxycarboxylic acid complex.
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 an alcohol solution of a zirconium complex with an alkanolamine at a mole ratio of 2 to 4 moles of alkanolamine per mole of zirconium to form a mixture which is a solvent-based alkanolamine complex of zirconium;
- (b) contacting the mixture with an {tilde over (α)}-hydroxycarboxylic acid at a mole ratio of 2 to 4 moles of hydroxycarboxylic acid per mole of zirconium for a period of time sufficient to stabilize the resulting solution of zirconium-alkanolamine-hydroxycarboxylic acid complex.
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 a solution of the zirconium-alkanolamine-hydroxycarboxylic acid complex comprising an aqueous liquid;
- a pH buffer;
- a cross-linkable organic polymer, and a solution of a zirconium-alkanolamine-hydroxycarboxylic acid complex wherein the solution is prepared by a process comprising:
- (a) contacting an alcohol solution of a zirconium complex with an alkanolamine at a mole ratio of 2 to 4 moles of alkanolamine per mole of zirconium to form a mixture which is a solvent-based alkanolamine complex of zirconium;
- (b) contacting the mixture with an {tilde over (α)}-hydroxycarboxylic acid at a mole ratio of 2 to 4 moles of hydroxycarboxylic acid per mole of zirconium for a period of time sufficient to stabilize the resulting solution of zirconium-alkanolamine-hydroxycarboxylic acid complex.
Dependencies are inferred from the claim text.