WATER SHUT OFF METHOD Russian patent published in 2009 - IPC E21B33/138 

FIELD: oil-and-gas production.

SUBSTANCE: invention related to oil-and-gas wells drilling, particularly to isolation of water ingress and water absorbing stratums, mostly for cases when in stratum waters diluted hydrogen sulfide is present. Method includes descending drillstem with opened ending into well up to the water ingress stratum bottom, pumping in slurry, consisting of cement, manganese peroxide, hardening accelerator for slurry and water, followed by cement bridge generation in front of water ingress stratum. But firstly define water ingress characteristics of stratum and study presents and amount of hydrogen sulfide in water, then base on this data prepare necessary amount of slurry adding extra fluid-loss additive at a rate 0.1-0.3 wt % of dry the cement. Upon that manganese peroxide added as per not less than 2 kg per 1 tonn of the cement. Alter pumping slurry into stratum at the first stage of its hardening apply pressure cyclically, which is not less than hydraulic fracturing pressure of stratum located above, also before pumping in slurry to push stratum waters deeper into stratum using buffer fluid with manganese peroxide content as per 1 kg per 1.0 m³ of buffer fluid and water resistant filler at a rate 0.5-1 kg per 1 m³ of buffer fluid.

EFFECT: isolation seal reliability increase, insulation quality increase.

3 cl, 4 dwg