METHOD FOR PAY ISOLATION AT CASING CEMENTING Russian patent published in 2008 - IPC E21B33/14 

FIELD: oil producing industry.

SUBSTANCE: invention is referred to oil producing industry, in particular to technology of well site construction and it is intended for well cementing drilled on oil, gas and water. The method for isolation of a pay at the casing cementing includes a running with a saddle on a bottom-hole of a casing string, equipped with the device for pay isolation in the form of the back pressure valves which have been placed at the pay base surface level, landing of oil well tubings with a trailer nipple, an injection in tubular annulus of calculated quantity of a working substance with a gravity equal to the gravity of a cement mortal, landing of oil well tubings prior pressure-tight interplay of a nipple with a saddle, an injection of a cement mortal and its pushing through by chaser in annular room of a casing string, hermetic sealing of internal room of a tubing string, an injection in tubular annulus of calculated quantity of chaser, dissociation of annular room of a hole and its development, as a working substance a cement mortal with hollow members is used, space filled by hardened at chilling by water or by a sandy-oil mixture, after a cement-slurry thickening and withstanding before fusion of specified water or a sandy-oil mixture under the influence of exterior factors the opening and a depression purification are carried out.

EFFECT: reliable isolation of a pay, extension of functionality due to realisation of the specified method at down hole performance with a pay having high injection capacity.

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