INTERVAL HYDRAULIC FRACTURING OF CARBONATE FORMATION IN HORIZONTAL WELLBORE WITH BOTTOM WATER Russian patent published in 2015 - IPC E21B43/27 

FIELD: oil and gas industry.

SUBSTANCE: method includes drilling of horizontal wellbore in productive stratum with cementing of casing string, lowering of perforator to the horizontal wellbore at the pipe string and performance of perforated openings in the horizontal wellbore with azimuth upward direction, lowering of the pipe string with a packer to the well, setting of the packer, pumping of breakdown agent through the pipe string and formation of hydraulic cracks in the horizontal wellbore. The horizontal wellbore in productive stratum is drilled in parallel to direction of the maximum stress in rocks. Then perforator is lowered to the horizontal wellbore at coil tubing (CT) and perforation openings are made in the horizontal wellbore in one row, then CT is pulled out from the well with perforator, the perforator is dismounted and the CT is equipped from below with an inflatable packer. CT is lowered up to the bottomhole by axial movement of CT from the mouth to the bottom to distance of 50m with speed rate of 0.5m/min and simultaneous pumping of viscous gel with density exceeding density of water in volume sufficient for filling with the following acid viscoelastic composite, wt %: gelling agent 12.0; 22% hydrochloric acid (HCl) 22.5; fresh water 65.5; in lower part of the horizontal wellbore section per 2/3 of the horizontal wellbore diameter. The inflatable parker is set, hydraulic fracturing is performed by pumping the following thickened acid composite, wt %: gelling agent 12.0; 22% hydrochloric acid (HCl) 68.0; fresh water 20.0; with further filling with gelling fluid with decomposer of perforated openings in the upper part of the horizontal wellbore section per 1/3 of the horizontal wellbore diameter. The inflatable packer releasing is made; then hydraulic fracturing is performed in the remaining part of the horizontal wellbore; to this end the above operations are repeated starting from the CT axial movement from the mouth to the bottom up to filling of the treated interval with gelling fluid with decomposer. Upon completion of interval hydraulic fracturing the well is developed by swabbing, at that viscoelastic gel is diluted at contact with stratal fluids and unblocks drained parts of the horizontal wellbore and then removed from the well.

EFFECT: increased efficiency of crack development, improved quality of hydraulic fracturing, reduced time for hydraulic fracturing.

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