METHOD FOR REPAIR INSULATION WORK USING SUSPENSIONS OF FINE MINERAL BINDER Russian patent published in 2016 - IPC E21B33/138 C09K8/467 

FIELD: mining.

SUBSTANCE: invention relates to sealing of integrity violation of production string and elimination of behind-casing flow in well. Method for repair-insulation works using a suspension of fine mineral binder involves determination of specific injectivity of isolated interval and injection of composition based on microcement and additives. When specific injectivity of isolated interval is less than 0.2 m³/(h·MPa) operation is carried out for increase thereof by acid treatment of isolated interval. Further geophysical investigations reveal violations of integrity of production casing and casing flows. When specific injectivity ranges from 0.2 to 1 m³/(h·MPa) method includes successively pumping into isolated interval a buffer from 0.5-1.0 m³ fresh water, based on composition and micro-cement additives buffer from 0.5-1.0 m³ fresh water is used as portland micro-cement with a specific surface of plugging at least 800 m²/kg and a composition as an additive of sodium salts of lignosulphonic acids, compositions based on synthetic polymers and modified sulphonated linear and branched polydimethylsiloxanes structure with following ratio of ingredients, pts.wt: portland cement backfill with a specific surface area of at least 800 m²/kg 100, water of 100-120, a composition based on sodium salts of lignosulphonic acids 0.2-1.0, composition based on synthetic sulphonated polymers 0.1-0.5, composition based on modified polydimethylsiloxanes and linear branched structure 0.08-0.15.

EFFECT: high efficiency of repair insulation work owing to longer time of hardening of microcement-based composition and improved strength characteristics of plugging stone.

1 cl, 1 tbl