HYDRAULIC FRACTURING METHOD FOR PRODUCING FORMATION WITH CLAY LAYER AND BOTTOM WATER Russian patent published in 2015 - IPC E21B43/26 

FIELD: oil and gas industry.

SUBSTANCE: method includes running in of the tubing string with a packer to the well, setting of the packer, hydraulic fracturing of the formation with injection of fracturing agent through tubing string with a packer through perforated interval with fracture forming and further fracture bonding, and releasing pressure from the well. Before run in of the tubing string with packer to the well orientation of the maximum stress in producing formation is defined by geophysical method. Then in the upper part of the producing formation perforation is carried out so that it is oriented towards direction of the maximum stress. Then the bottom part of the producing part is cut off. The tubing string with packer is run in to the well so that the lower end of the tubing string is at the level of the producing formation roof, the packer is set, hydraulic fracturing is performed with injection of fracturing agent, and to this end linear gel is used with consumption rate of 0.3 m³/min with generation of fracture in the producing formation. Then the fracture is bonded in the producing formation through the tubing string and oriented perforated interval in the formation during four cycles of alternated injection of linear gel with lightweight proppant of 20/40 by even portions and crosslinked gel with addition of NaCl salt with concentration of 400 kg/m³ by even portions. At that even portions of crosslinked gel in volume are twice less than even portions of linear gel, and quantity of crosslinked gel portions is less per one portion than linear gel portions. Moreover concentration of lightweight proppant of 20/40 mesh in linear gel is increased by steps per 100 kg/m³ from the first up to third portion in each cycle starting from concentration of 100 kg/m³; in the fourth last cycle one portion of linear gel is carried out with lightweight proppant of 16/20 mesh with concentration of 400 kg/m³, then 15%-aqueous solution of hydrochloric acid is injected and flushed into the fracture in producing formation in volume equal to half of the total volume of linear gel and crosslinked gel injected into the fracture during bonding process.

EFFECT: improved reliability of the method implementation and improved efficiency of hydraulic fracturing.

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