CARBONATE FORMATION HYDRAULIC FRACTURING METHOD Russian patent published in 2018 - IPC E21B43/26 E21B43/27 

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry and may be used in hydraulic fracturing of a carbonate formation (FGD). Method includes perforating the walls of the well in its necessary interval with channels of a depth not less than the extent of the stress concentration zone in the rocks from the wellbore, descent of the tubing string into the zone of fracturing with sealing of the annular space with a packer above the perforation interval, cyclic injection and squeezing of a gel-like fracturing fluid and acid into the well. In this case, the permeability and thickness of the formation are predetermined. As a gel-like fracturing fluid, a linear gel with a concentration of 3 kg/m³ is used, prepared at the rate of 1.5 m³ on 1 m of a layer thickness, and as acid – a mixture of hydrochloric and hydrofluoric acids, prepared at the rate of 1 m³ per 1 m of the formation thickness, mixture of a 15 % aqueous solution of hydrochloric acid and a hydrocarbon solvent, prepared at a rate of 0.5 m³ per 1 m of the thickness of the formation. Prepared solutions are divided into three equal portions and sequentially injected in three cycles. Moreover, at a permeability of more than 100 mD, a mixture of a 12 % aqueous solution of hydrochloric acid and a 3 % aqueous solution of hydrofluoric acid is pumped, and a mixture of a 15 % aqueous solution of hydrochloric acid with a hydrocarbon solvent at a ratio of 9:1, with a permeability of 20 to 100 mD, a mixture of a 10 % aqueous solution of hydrochloric acid and a 2 % aqueous solution of hydrofluoric acid is pumped, and a mixture of a 15 % aqueous solution of hydrochloric acid with a hydrocarbon solvent at a ratio of 8:2, with a permeability less than 20 mD, a mixture of a 6 % aqueous solution of hydrochloric acid and a 1 % aqueous solution of hydrofluoric acid is pumped, and a mixture of a 15 % aqueous solution of hydrochloric acid with a hydrocarbon solvent at a ratio of 7:3. After completion of the last injection cycle, the squeezing is carried out with fresh water.

EFFECT: technical effect: to maintain the conductivity of the fracture after the fracturing with increasing efficiency of hydraulic fracturing.

1 cl, 3 dwg