METHOD OF PREPARING COMPOSITIONS OF ZIRCONIUM-BASED CROSS-LINKING AGENT AND USE THEREOF AT OIL DEPOSITS Russian patent published in 2013 - IPC C09K8/68 C09K8/88 E21B43/26 E21B33/138 

FIELD: chemistry.

SUBSTANCE: invention relates to zirconium chelates and use thereof at oil deposits. The method of preparing a solution of a zirconium-alkanolamine-hydroxy carboxylic acid complex involves a step where an alcohol solution of a zirconium complex is brought into contact with alkanolamine and then with α-hydroxy carboxylic acid to obtain said solution. The cross-linking composition contains an aqueous liquid, a pH correcting buffer and said solution. A method for hydraulic fracturing an underground formation involves pumping said composition into the formation at a rate and pressure sufficient to form, reopen and/or widen cracks. A method for selective plugging permeable zones and leaks in underground formations involves pumping said composition into a permeable zone or leakage point. The invention is developed in subclaims.

EFFECT: providing satisfactory viscosity of the cross-linking composition during hydraulic fracturing and plugging permeable zones in underground formations at high pH and temperature in the formation of 275°F (135°C) or higher.

11 cl, 4 ex, 1 tbl