METHOD OF PRODUCTIVE FORMATION HYDRAULIC FRACTURING WITH CLAY LAYER AND GAS-BEARING HORIZON Russian patent published in 2017 - IPC E21B43/26 C09K8/80 

FIELD: oil and gas industry.

SUBSTANCE: method involves performing the perforation in the range of productive formation of the well oriented in the direction of the main maximum voltage, landing of tubing string with packer to a well, packer seating, performing hydraulic fracturing treatment (HFT) by hydraulic fracture liquid injection by the tubing string with packer through perforated interval to the production string with obtaining and further fracture fixation by propping agent, pressure relief in the well, packer releasing and its extraction with a tubing string from the well. Oriented perforation is carried out using slot perforator with an orienting sub, HFT process begins with pumping of the fracturing fluid, a cross-linked gel is used as the fracturing fluid to create a crack in the productive formation. After that the created crack is developed by injecting linear gel with density of 1150 kg/m³ at first with ultralight proppant with fraction of 40/80 mesh with a concentration of 200 kg/m³, and then with quartz fine-grained sand with a grain size of 0.1-0.25 mm and concentration of 600 kg/m³. Then the crack is fixed by injecting crosslinked gel with fraction of 20/40 mesh proppant or 12/18 mesh, depending on the permeability of the productive formation by portions with stepped increasing of proppant concentration to 100 kg/m³, starting from 200 kg/m³ to 800 kg/m³, the last portion of the RCP-proppant is pumped with concentration of 900 kg/m³. The crosslinked gel with a fraction proppant of 20/40 mesh is pumped into a productive formation with a permeability from 0.01 to 100 mD during fixation of the crack, while in a productive formation with a permeability from 100 to 500 mD the crosslinked gel is pumped with a proppant of 12/18 mesh during fixation of the crack.

EFFECT: increased reliability of the creation and development of the crack; improved process efficiency, reduction of hydraulic resistance in the range of perforation, quality improvement in fixing the crack in the bottomhole formation zone and the exclusion of injecting proppant into the well during the subsequent development.

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