METHOD OF HYDRAULIC FRACTURING OF WELL FORMATION Russian patent published in 2013 - IPC E21B43/26 

FIELD: oil and gas industry.

SUBSTANCE: method 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; installation of packer above roof of perforated productive formation; pumping to under-packer zone of fracturing fluid gel to carry out formation hydraulic fracturing (FHF); creation of formation hydraulic fracturing pressure in under-packer zone and pumping of fracturing fluid gel with binding agent of fractures to the formed formation fracture. According to the invention, before formation hydraulic fracturing is performed, the pipe string is filled with process liquid and total volume of fracturing fluid gel is determined as per analytical expression. Then, formation hydraulic fracturing is performed. First, fracturing fluid gel is pumped without adding any binding agent for creation of fracture. Then, the rest volume of fracturing fluid gel with binding agent of fractures is pumped. As a binding agent of fractures there used is superlight proppant with the fraction of 20/40 mesh by gradual increase in concentration of the proppant in fracturing liquid of 200 kg/m³ to 1000 kg/m³. As fracturing fluid gel there used is a line gel with simultaneous addition of a borate cross-linking agent and a destructor. Borate cross-linking agent is added to the line gel with concentration of 2.0 to 4.0 l/m³, which is sufficient for complete cross-linking of fracturing fluid gel at the well perforation zone. The destructor is added with gradual increase in concentration by 0.15 kg/m³, starting from the concentration of 1.0 kg/m³. Upon completion of pumping of fracturing fluid gel with the binding agent of fractures to the pipe string there performed is their forcing-through to the formation with process liquid. Exposure is performed during the period of time, which is necessary for pumping pressure drop by 70-80% of forcing-through pressure to the formation of fracturing fluid gel with the binding agent of fractures; the packer is unpacked, and the above packer and the pipe string is removed to the surface.

EFFECT: improving efficiency of the method owing to increasing the width of fracture and value of its penetration and reduction of the commissioning period of the well.

3 ex, 1 dwg