METHOD OF HYDRAULIC FRACTURING OF CARBONATE FORMATION Russian patent published in 2012 - IPC E21B43/26 E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: method of hydraulic fracturing (HF) of carbonate formation in well includes perforation of well walls in required well interval by channels with depth not less than length of stress concentration zone in rocks from well shaft, lowering of pipe string to HF zone with sealing of intertube space by packer above perforation interval and cyclic pumping of fracturing jelly-like liquid to well. Before HF performance well is filled with process liquid in the volume of 0.2-0.4 of well shaft volume, total volume of pumped fracturing jelly-like liquid is calculated by formula: V_j=k*H_p, where V_j - volume of pumped fracturing jelly-like liquid, m³; k=1.4÷1.6 - conversion factor, m³/m; H_p - opening interval length, m. Fracturing jelly-like liquid is pumped in equal portions in 3-5 cycles, after that acid portions are pumped in the volume of 0.7-0.75 of volume of fracturing jelly-like liquid, after completion of the last pumping cycle marketable oil or fresh water is pumped in one-and-a-half volume of pipe string with further exposure during 1-2 hours, after that products of acid reaction with rock are removed, packer is dismounted and removed from well with pipe string.

EFFECT: increasing efficiency of hydraulic fracturing in carbonate rocks under low pressure of formation by means of reducing fracturing pressure upon cracking with possibility to prevent flooding of wells after hydraulic fracturing even if water-bearing horizons are close, simplifying technical process.