METHOD OF SEALING RECOVERY OF PRODUCTION STRING Russian patent published in 2012 - IPC E21B33/13 C09K8/50 

FIELD: oil and gas production.

SUBSTANCE: sand bridging is installed before injection in the well below the defect of production string and cement bridging 5-10 m is installed above the perforation interval. The oil is injected through tubing on the basis 2 m per 1 m of the strata net thickness and water is forced out of the insulation zone. After that the solution of Mikrodur R-U with sulfatsell is pumped in with water-cement ratio 0.8-0.9 on the basis of 0.5-2.0 m per 1 m of the strata net thickness with the following component ratio, wt %: Mikrodur R-U 51.4-54.9; sulfatsell 2.3-1.1; water 46.3-44.0.

EFFECT: increase of insulation reliability in case of sealing failure of production string, reduction of insulating works period.

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