METHOD FOR HYDRAULIC FRACTURING OF FORMATION IN HORIZONTAL SHAFT OF WELL Russian patent published in 2017 - IPC E21B43/267 E21B43/11 

FIELD: oil and gas industry.

SUBSTANCE: method involves drilling of a horizontal shaft of the well in an oil-saturated part of the productive formation, lowering of the casing column into the horizontal shaft of the well and cementing of the annulus space between the casing column and the rock, performing hydromechanical perforation in all intervals of productive formation, extraction of the pipe string with hydromechanical perforator from the well, lowering of the pipe string with packer and performing interval HFT in the direction from the bottom to the wellhead in each perforated interval of casing column with a consequential abandonment of each interval. After drilling a horizontal shaft of the well, geophysical surveys are carried out and thickness and length of the oil-saturated intervals of the productive formation are determined, a map of oil-saturated intervals of productive formation is built according to the horizontal shaft of the well with an indication of their thicknesses and lengths, then hydromechanical perforation of the casing column is performed in the oil-saturated intervals of the productive formation. Pairs of perforations are made along the perimeter of the casing column in the direction from the bottom to the wellhead, positioned an angle of 180° relative to each other and with offset at an angle of 30° when producing each pair of the perforations. When the thickness of the productive formation oil-saturated interval is under 10 m HFT is performed using an acid gel without crack fixing, when the thickness of the productive formation oil-saturated interval is from 10 to 20 m HFT is performed using the hydrocarbon-based gel with fixing of tension crack by pumping the carrier fluid with proppant of 20/40 mesh fraction and concentration of 800 kg/m³, when the thickness of the productive formation oil-saturated interval is over 20 m HFT is performed using a cross-linked aqueous gel with fixing of tension fracture by pumping the carrier fluid with proppant of 12/18 mesh fraction and concentration of 1200 kg/m³.

EFFECT: increased efficiency of hydraulic fracturing, simplified implementation process of hydraulic fracturing, improved reliability of hydraulic fracturing, increased coverage of productive formation with tension cracks.

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