METHOD FOR TREATING BOTTOMHOLE ZONE OF FORMATION WITH HYDROGEN PEROXIDE WITH PHLEGMATIZATION DURING DEVELOPMENT Russian patent published in 2023 - IPC E21B43/243 C09K8/592 E21B49/08 

FIELD: oil and gas industry.

SUBSTANCE: method of treating the bottomhole zone of a formation with hydrogen peroxide with phlegmatization, which includes pumping a solution of hydrogen peroxide through the tubing, its decomposition in the formation with the release of heat, during development, the well is washed with the tubing lowered to the bottom, tightness of the pipe string is assessed, and well injectivity is determined. With injectivity of ≥ 50 m³/day, process tubing with a packer is lowered, while the packer is installed above the perforation interval, then fresh water is injected as a buffer fluid in a volume equal to 1.2 volumes of the tubing, after which a 37 wt.% hydrogen peroxide solution is injected. Then the said hydrogen peroxide solution is forced into the formation with fresh water with a volume of 1 m³, then with process water, a total of 1.2 times the volume of tubing, while the entire volume of injection is carried out in less than 5 hours, provided that the chemicals supply rate is uniform. Next, the well is shut in for reaction while pressure at the wellhead is recorded. At a pressure of 60-65 atm. and no increase in pressure for more than 2 hours, the decomposition reaction of hydrogen peroxide is considered complete. If there is no increase in pressure during decomposition of hydrogen peroxide in the formation, an aqueous solution of the catalyst - 5 wt.% potassium permanganate - is injected in a volume equal to the volume of the injected hydrogen peroxide. Then the catalyst solution is pressed with process water in a volume equal to 1.2 times the volume of the tubing. Then, at a pressure of 60-65 atm. and no pressure increase for more than 2 hours, nitrogen is injected. At the wellhead, liquid and separated gas are released into the oil carrier and disposed of, while during the process of nitrogen injection, oxygen in the composition of the separated gas is measured. After complete bleeding, the well is swabbed with a volume of at least 2 times the volume of the injected liquid. Next, to clarify the well flow rate, studies are carried out to restore the fluid level in the tubing and the tubing is lifted with a packer. Then the pump is lowered with the calculated flow rate according to the study results. In this case, development of the well is accompanied by the measurement of oxygen in the composition of the produced liquid into the oil tanker; at the minimum permitted concentration of oxygen in the liquid, development is switched to the oil pipeline.

EFFECT: safety of treatment of the bottomhole zone of the formation using hydrogen peroxide.

1 cl, 1 dwg, 5 tbl, 2 ex