FLUID VISCOSITY REGULATING FLUID FOR USE IN HYDRAULIC FRACTURING OF FORMATION Russian patent published in 2019 - IPC C09K8/536 C09K8/92 E21B43/267 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to treatment of underground formation of oil or natural gas and can be used at control of viscosity of liquid used in hydraulic fracturing of underground formation. Viscosity adjusting agent used to control viscosity change of fluid for hydraulic fracturing of the formation contains polyalkylene oxide and viscosity reducing substance and has the form of tablet, where the proportion of polyalkylene oxide in said agent ranges from 30 to 99.99 % by weight, amount of said agent in hydraulic fracturing fluid ranges from 0.01 to 1 % by weight, tablet weight is 0.2 g or more and polyalkylene oxide has viscosity of 20 to 1,500 mPa⋅s in form of 0.5 wt% aqueous solution at 25 °C or viscosity of 50 to 80,000 mPa⋅s in form of 5 % by weight aqueous solution at 25 °C. Use of a tablet containing a polyalkylene oxide and a viscosity reducing substance as an agent for controlling the viscosity of the fluid for hydraulic fracturing of the formation, where the proportion of polyalkylene oxide in said agent ranges from 30 to 99.99 % by weight, amount of said agent in hydraulic fracturing fluid is from 0.01 to 1 % by weight, tablet weight is 0.2 g or more and polyalkylene oxide has viscosity of 20 to 1,500 mPa⋅s in form of 0.5 wt% aqueous solution at 25 °C or viscosity of 50 to 80,000 mPa⋅s in form of 5 % by weight aqueous solution at 25 °C. Method for controlling viscosity change of fluid for hydraulic fracturing of a formation containing the above tablet. Fluid for hydraulic fracturing of the formation contains the above viscosity control agent, water, proppant and gel-forming agent. Method of developing an oil or natural gas formation comprising producing a production well shaft in a formation, introduction of said fluid for hydraulic fracturing into production well bore for hydraulic fracturing in part of stratigraphic horizon and production of oil or natural gas from production well shaft. Invention is developed in dependent items of the formula.

EFFECT: higher efficiency of treatment.

10 cl, 5 dwg, 2 tbl, 28 ex