FIELD: chemistry.
SUBSTANCE: invention relates to borozirconate compositions used in oil extraction. The method of producing a solution of a borozirconate complex suitable for cross-linking in a hydraulic fracturing fluid involves contacting a zirconium complex with an alkanolamine at a ratio of 2-10 moles of the alkanolamine per mole of zirconium to form a first mixture; contacting the first mixture with water at a ratio of 2-10 moles of water per mole of zirconium and with 0-2 moles of a hydroxyalkylene diamine per mole of zirconium to form a second mixture; and contacting the second mixture with 1-4 moles of a boron compound per mole of zirconium in an alcohol at a temperature of 25-90° C. A method for hydraulically fracturing a subterranean formation involves 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 said solution of a borozirconate complex. A method for selectively plugging permeable zones and leaks in subterranean formations involves introducing into the permeable zone or the site of the subterranean leak, said cross-linking composition. The invention is developed in subclaims.
EFFECT: high resistance of the cross-linking agent to duration of storage and wider temperature range when used in oil extraction.
12 cl, 10 ex, 2 tbl
