METHOD OF GAS ISOLATION IN OIL WELLS Russian patent published in 2025 - IPC E21B33/138 C09K8/493 

FIELD: oil industry.

SUBSTANCE: invention relates to the oil industry, in particular to a method for shutting off gas influx in oil wells. Claimed method of gas isolation in oil wells consists in successive pumping of foam gel and hydrogel fringes. At that, fringe of surfactant foaming composition is preliminary pumped. Ratio of volumes of rims of foaming surfactant composition, foam gel and hydrogel rims is 3:5:1, respectively. the foaming surfactant composition used is 2% solution in water of the composition Neonol “АФ9-6”, Kaskad KM, an alcohol solvent with weight ratio of 50.7%, 25.5% and 23.8%. Alcohol solvent contains 46% methanol, 29% ethylene glycol, 7% dimethyl carbonate and 18% water. Foam-gel rim contains PAA – 0.75%; chromium acetate – 0.2%; sodium nitrite – 6.0%; ammonium chloride – 4.7, fresh water – the balance. Hydrogel rim contains PAA – 1.7%; paraform – 0.15%; resorcin – 0.05%, fresh water – balance. 0.4% nanosilica is added to the composition of the foam gel and/or hydrogel rim.

EFFECT: higher gas blocking capacity defined by critical pressure gradient and residual resistance factor.

3 cl, 2 tbl