METHOD OF BOTTOM-HOLE REGION LINING Russian patent published in 2012 - IPC E21B33/13 C09K8/44 C09K8/467 

FIELD: oil-and-gas industry.

SUBSTANCE: invention relates to underground repair of wells. Proposed method comprises injecting foamed polymer solution in the well containing the following component, in wt %: anionic water-soluble polymer or its emulsion in oil 0.15-5.0, surfactant or its mix 0.1 -20.0, urea-formaldehyde concentrate or products based thereon 0.5-20.0, salt of polyvalent metal 0.01-0.30, ammonium chloride 0.32-7.0, sodium nitrite 0.41-8.96, and water making the rest. Then injected is porous cementing solution containing the following components in wt %: silicon-bearing substance or mixes thereof 39.04-96.27, urea-formaldehyde concentrate or products based thereon 3.0-50.0, ammonium chloride 0.32-7.0, and sodium nitrite 0.41-8.96. Foamed polymer solution may additionally contain inorganic or organic acid, or mix thereof in amount of 0.1-0.5 wt % and silica-alumina hollow spheres in amount of 0.5-10 wt %, while porous cementing solution may included filling agent in amount of 0.5-10.0 wt % and water-retaining additive in amount of 1.0-5.0 wt %.

EFFECT: higher efficiency, increased oil-sweeping properties.

5 cl, 4 tbl, 2 dwg