COMPOSITION FOR TREATMENT OF BOTTOMHOLE ZONE OF OIL AND GAS FORMATION Russian patent published in 2021 - IPC C09K8/52 C09K8/72 C09K8/74 C09K8/78 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil and gas industry, in particular to compositions for treating the bottomhole zone of the wellbore in order to remove the filter cake formed during filtration of the drilling fluid when completing the well with an open bottomhole. The composition for treating the bottomhole zone of an oil and gas formation includes, wt%: potassium fluoride peroxosolvate KF·H₂O₂ 0.7-15; ammonium nitrate NH₄NO₃ 0.5-15.0; water - the rest. The composition may additionally contain: acid component - hydrochloric acid in an amount of 0.001-0.5 wt.% to ensure the pH of the composition is less than 7; alkaline component - potassium hydroxide in the amount of 0.001-0.2 wt.% to ensure the pH of the composition is more than 7; ionic or nonionic surfactant or a mixture thereof in the amount of 0.01-5.0 wt.%; a corrosion inhibitor in the amount of 0.01-5.0 wt%; enzyme - α-amylase in the amount of 0.5-5.0 wt.%.

EFFECT: ensuring the ability to control the rate and start time of the filter cake dissolution reaction in the range from 2 to 24 hours when treating the bottomhole zone of an oil and gas reservoir, increasing the uniformity of filter cake removal, preventing the formation of secondary insoluble sediments while simplifying the processes of transportation and application of the composition.

6 cl, 4 tbl, 6 ex