METHOD OF REPAIR-INSULATION WORKS IN WELL (VERSIONS) Russian patent published in 2016 - IPC E21B33/138 C09K8/46 

FIELD: oil industry.

SUBSTANCE: invention relates to oil industry, in particular, to repair-insulation works in wells using plugging compositions. Method for repair-insulation work in well includes preparation and pumping into well of cement composition, containing structure-forming agent, structure-forming initiator and reinforcing fibre. Structure-forming agent used in backfill composition is portland cement grouting or gel-cement, consisting of a mixture of portland cement grouting and clay powder in amount of 5-20 % of weight of portland cement grouting, or liquid glass or organosilicon products, or phosphogypsum. Structure-forming initiator is fresh water or salt of polyvalent metals (calcium chloride, aluminum chloride, chromium acetate, mineralised formation water), reinforcing fibre used is a synthetic construction micro-reinforcing fibre or mineral reinforcing fibre - basalt, wherein diameter of fibres is 10-35 mcm, and length is 3-18 mm, fibre is added in amount of 0.5-5 kg per 1 m³ of cement composition. Pumping of plugging composition is performed in multiple portions depending on specific injectivity of disturbance, so that when specific injectivity of disturbance from 1.5 to 4 m³/(h·MPa) pumping is started using fibre with increase of its length with pumping from 3, 6, 12 to 18 mm, and when specific injectivity is from 4 to 20 m³/(h·MPa) in multiple portions with reduced length of fibre from 18, 12, 6 and up to 3 mm.

EFFECT: technical result of disclosed invention is improvement of efficiency of remedial cementing works in well owing to use of cement composition with higher sealing capacity.

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