METHOD OF HYDRAULIC GRADUATION OF A FORMATION WITH CLAYEY SPACES Russian patent published in 2018 - IPC E21B43/267 C09K8/80 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas production industry and can be used for hydraulic fracturing of a productive formation located between non-collector rocks - clay interlayers. Method includes perforating the formation using charges of large diameter and deep penetration, descending the tubing string - tubing - with the packer into the well, planting the packer, hydraulic fracturing of the reservoir - fracturing by injection through a well along a tubing string with a packer into the productive formation of a hydrofracturing liquid - crosslinked gel followed by injection of proppant through the interval of formation perforation, bleeding of pressure from the well. Perforation of the formation is carried out under the roof in the upper 1/4 part of the height of the formation and above the sole in the lower 1/4 part of the height of the formation using deep penetration charges, and in the middle 1/2 part of the height of the formation, the perforation is performed using charges of larger diameter, after which the formation fluid is taken through intervals of perforation of the formation in a volume of 5 m³. Further, lower the tubing string with the packer into the well so that the lower end of the tubing string is at the level of the formation roof, then plant the packer in the well. Then, by injecting a hydrofracturing fluid, a crosslinked water-based gel in a volume of 6 m³ - initiate the development of a crack with its subsequent development in length and attachment by sequential injection of three portions of proppant of different fractions. First portion containing proppant of fine fraction of 20/40 mesh with a mass of 30% of the total proppant mass, second portion is a 16/20 mesh medium proppant with a mass of 50% of the total proppant mass, third portion is a proppant of a coarse fraction of 12/18 mesh with a mass of 20% of the total mass of the proppant, wherein the injection of proppant fractions of each portion is performed with a step change in the flow rate,

first portion is pumped at a flow rate of 2.5 m³/ min, the second portion - at a flow rate of 3.0 m³/ min, the third portion - at a rate of 3.5 m³/ min.

EFFECT: technical result is the increase of the efficiency of hydraulic fracturing.

1 cl, 3 dwg