INSULATION COMPOSITION AND METHOD OF WELL TUBING-CASING ANNULUS PLUGGING Russian patent published in 2006 - IPC E21B33/138 

FIELD: oil production industry, particularly methods and devices to prevent showings of oil and gas in cemented tubing-case annulus.

SUBSTANCE: insulation composition includes solution comprising urethane pre-polymer, solvent and hardener - water. The solvent is polar solvent chosen from aromatic series or from chlorinated hydrocarbon series. The water is mineralized water containing surfactant additive. All above components are taken in the following amounts: urethane pre-polymer - 20-75 parts by weight, solvent - 25-80 parts by weight, hardener - 1.5 parts by weight per 100 parts by weight of the solution. Tubing-casing annulus plugging method involves filling fluid channels of cemented tubing-casing annulus with above insulation composition in four stages. At the first stage gaseous agent is injected in the tubing-casing annulus up to full liquid phase displacement from fluid channels. At the second stage the channels are filled with hydrocarbon waterless liquid having low viscosity and increased penetrability. At the third stage above urethane pre-polymer composition is injected in tubing-casing annulus. At the forth stage tubing-casing annulus is filled with hardener.

EFFECT: possibility of tubing-casing annulus plugging by injection method without well operation stoppage, increased plugging quality due to increased composition penetration depth and increased fullness of fluid channel filling.

2 cl, 4 tbl