METHOD OF FORMATION HYDRAULIC FRACTURING Russian patent published in 2015 - IPC E21B43/26 C09K8/62 

FIELD: oil and gas industry.

SUBSTANCE: method of formation hydraulic fracturing (FHF) involves perforation of well walls at formation interval with channels with the depth that is not less than length of stress concentration zone in rocks from the well shaft; lowering of pipe string with packer; setting of packer above roof of the perforated productive formation; pumping to under-packer zone of fracturing fluid gel with binding agent of fractures to the formed formation fracture. Proppant is used as binding agent of fractures. Concentration of proppant is increased step by step from 200 up to 1000kg/m³. Upon completion of injection of fracturing fluid gel with proppant chemical a reagent represented by mixture of urea solution CO(NH₂)₂ with addition of urease enzyme solution and calcium nitrate solution Ca(NO₃)₂ is injected to the pipe string in proportion of 0.7:0.1:0.2. Volume of the injected agent is determined by the mathematical formula considering volume of the injected reagent, thickness of the formation penetrated by perforation, porosity of the formation and binding radius of proppant in fracture of bottomhole formation zone as well as intake rate of the formation subjected to hydraulic fracturing. Thereafter the reagent is flushed to the formation with process fluid in 1.5-multiple volume of the pipe string volume, then the process is withhold within 24 hours, the packer is released and removed together with the pipe string to the surface.

EFFECT: method allows increasing efficiency of hydraulic fracturing due to excluded outflow of the proppant from bottomhole formation zone as well as increasing conductivity of the fracture due to even distribution of proppant in the fracture in bottomhole formation zone.

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