HYDRAULIC FRACTURING METHOD FOR LOW-PERMEABLE BED WITH CLAY LAYERS AND BOTTOM WATER Russian patent published in 2015 - IPC E21B43/267 

FIELD: oil and gas industry.

SUBSTANCE: method includes running of production string with packer in to the well, setting of the packer, hydraulic fracturing by injecting fracturing fluid through production string with packer to the producing reservoir with further proppant injecting through perforated interval in the low-permeable bed, pressure releasing from the well. Additionally perforated interval in the low-permeable bed is isolated temporary, the interval of clay layer is perforated using alternating charges of large diameter and deep invasion; then the production string with packer is lowered so that the lower end of the production string is at the level of clay layer roof, the packer is set in the well, the low-permeable bed is fractured with formation of cracks by injection of fracturing fluid along the production string through perforated intervals in clay layer. Then bank of oil-based cross-linked gel is injected to cracks in volume of 3-5 m³ with flow rate of 10 m³/min. Proppant moisture is used as proppant. Then cracks are reinforced by dosed injection of fracturing fluid and proppant mixture starting with concentration of 400 kg/m³ for proppant mixture with stepped increase of its concentration in fracturing fluid per 200 kg/m³ for each dose and flow rate of 5 m³/min. The proppant mixture is made at the wellhead with the following ratio of components, wt %: proppant 12/40 mesh - 30%; proppant 18/20 mesh - 30%; quartz flour - 40%. Upon completion of hydraulic fracturing of low-permeable bed temporary isolation is removed from the perforated interval of the low-permeable bed with formation of hydraulic connection between the borehole and created fracture.

EFFECT: improved reliability of hydraulic fracturing for low-permeable bed with clay layers and bottom water.

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