BOOSTERS FOR BREAKERS CONTAINING IRON COMPOUNDS Russian patent published in 2019 - IPC C09K8/588 C09K8/68 C09K8/86 E21B43/267 

FIELD: chemistry.

SUBSTANCE: present invention relates to boosters for breakers containing iron compounds, and methods for use thereof in hydraulic fracturing of a subterranean formation. Method of hydraulic fracturing of an subterranean formation penetrated by a well bore, including a step of injecting a well treatment fluid into the well bore at a pressure and flow rate sufficient to fracture the subterranean formation, where the well treatment fluid comprises water, at least one acrylamide-containing polymer, one or more ferrous salts and one or more booster compounds, where the amount of said salt is approximately from 0.001 to 0.05 % of the volume of the well treatment fluid, and one or more booster compounds are selected from a group consisting of urea, ethylenediaminetetraacetic acid – EDTA, EDTA salts, citric acid, aminotricarboxylic acid and salts thereof, polyphosphonate and polyphosphate compounds, boric acid and salts thereof, carbonate salts of alkali metals, diethylenetriaminepentaacetic acid – DTPA, humic acids and lignosulphates. Method of hydraulic fracturing a subterranean formation penetrated by a well bore comprises steps of: (I) injecting a first well treatment fluid comprising at least one acrylamide-containing polymer into the well bore at a pressure and flow rate sufficient to fracture the subterranean formation, and (II) injecting a second well treatment fluid comprising one or more ferrous salts and one or more booster compounds into the well bore, where the amount of said salt is approximately from 0.001 to 0.05 % of the volume of the well treatment fluid, and one or more booster compounds are selected from the group given above. Method of hydraulic fracturing a subterranean formation penetrated by a well bore comprises steps of: (I) injecting a first well treatment fluid comprising at least one acrylamide-containing polymer into the well bore at a pressure and flow rate sufficient to fracture the subterranean formation, (II) injecting a second well treatment fluid comprising one or more ferrous salts and one or more booster compounds into the well bore, where the amount of said salt is approximately 0.001 to 0.05 % of the volume of the well treatment fluid, and (III) injecting a third well treatment fluid comprising one or more booster compounds selected from the group given above into the well bore. Well treatment fluid comprising water, at least one acrylamide-containing polymer, one or more ferrous salts, and one or more booster compounds, where the amount of said salt is approximately from 0.001 to 0.05 % of the volume of the well treatment fluid, and one or more booster compounds are selected from the group given above. Method for reducing the viscosity of a well treatment fluid, comprising adding one or more ferrous salts and one or more booster compounds to said fluid, where the fluid comprises water, at least one acrylamide-containing polymer, the amount of said salt is approximately 0.001 to 0.05 % of the volume of the well treatment fluid, and one or more booster compounds are selected from the group given above. Invention is developed in dependent items of the formula.

EFFECT: higher efficiency of removing the polymer used in treatment once treatment is complete.

13 cl, 1 ex, 1 dwg