PREPARATION METHOD OF COMPOSITION FOR ISOLATION OF BEHIND-CASING FLOWS IN WELL Russian patent published in 2015 - IPC E21B33/138 C09K8/66 

FIELD: oil and gas industry.

SUBSTANCE: in a preparation method of compositions for the isolation of behind-the-casing flows in a well that includes mixing of microcement and additives, oil well portland cement with the specific surface of 800 or 900 m²/kg is used as the microcement and a water-soluble acrylamide polymer, copolymer of vinyl amide and n-vinyl lactam, olefin sulphonate and polyethylene glycol at the water-cement ratio of 0.75-1.2 are used as the additives for the preparation of the composition; a microcement grouting fluid is prepared preliminarily with a solution of the above listed additives in water at simultaneous stirring, then the microcement is added to the produced fluid with the following ratio of ingredients, in weight parts: oil well portland cement with the specific surface of 800 or 900 m²/kg - 100, water-soluble acrylamide polymer - 0.01-0.02, copolymer of vinyl amide and n-vinyl lactam - 1.0-2.5, olefin sulphonate - 0.01-1.0, polyethylene glycol - 0.05-0.15, and water 75-120.

EFFECT: improved workability and efficiency in the isolation of behind-the-casing flows in the well due to the increased strength and expanded time range for hardening of the microcement-based composition.

1 tbl