VISCOELASTIC COMPOSITION FOR WELL KILLING Russian patent published in 2024 - IPC E21B33/138 C09K8/42 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to compositions for treating drill wells, namely to compositions for killing wells, and can be used when carrying out work in high-temperature fields with fractured carbonate type reservoirs and high absorption of killing fluid. The viscoelastic composition contains 4-7 wt.% of partially hydrolysed polyacrylamide with a degree of hydrolysis of 2.5-7.5%, 0.087-0.237 wt.% of trivalent chromium salt in terms of chromium, and water - the balance. Moreover, the composition additionally contains 3.1-17.6 wt.% of an encapsulated complex destructor. Moreover, the encapsulated complex destructor contains 1.6-12.6 wt.% of encapsulated hydrogen peroxide adduct with a polymer coating and 1.5-5.0 wt.% of encapsulated complexon with a polymer coating.

EFFECT: increase in the strength of the resulting gel, adjustable cross-linking time, adjustable time of gel destruction without the formation of secondary sediments and while maintaining the filtration-capacitive properties of the formation.

5 cl, 2 dwg, 2 tbl