PROCEDURE FOR TREATMENT OF BOTTOMHOLE ZONE OF PRESSURE WELL Russian patent published in 2011 - IPC E21B43/22 E21B43/25 

FIELD: oil and gas production.

SUBSTANCE: procedure for treatment of bottomhole zone of pressure well -the BZPW- consists in lowering flexible coiled tubing into well to depth below interval of perforation. Further, there is pumped 0.8-1.2 % washing solution of Neftenol K of grade "NK-20" in process water at amount of 2-3 volumes of production string (column of pipe-compressor tubes- the CPCT). There is washed zone of perforation and the CPCT. The well is washed with 0.08-0.12 % solution of ML-81B in process mineralised water to a "clear water". Solution is pumped to clean perforation openings - it is 3-5 % solution of Neftenol K of grade "NK-20" in 12.0-24.0 % solution of inhibited hydrochloric acid of volume of 2-6 m³ - through said pipe at an open pipe gate. Further, at a closed pipe gate, at amount of volume of the said tubing, solution for cleaning is pressurised into a reservoir with 0.08-0.12 % solution of ML-81B; it is conditioned under pressure for 4-8 hours, then pressure is dropped, products of reaction at amount of 2-4 volumes of pumped cleaning solution are withdrawn, the well is washed with mineralised water to a "clear water". Water solution is pumped to the well up to the interval of perforation through the said tubing at the open pipe gate. This processing water solution has composition, %: 3-6 of dry acid "DA-TK 4", 1-4 of Neftenol K of grade "NK-20", 0.025-0.05 of corrosion inhibitor "CIU-118". Successively, the gate is closed, treatment solution is pumped into the reservoir at amount of from 1.5 to 2 m³/m of perforated thickness of reservoir with 0.08-0.12 % solution of ML-81B at amount of not less, than volume of the said tubing +1 m³ and not more, than summary volume of treatment solution and volume of the said tubing. Solution is conditioned under pressure for 8-24 hours. Pressure is dropped and products of reaction are withdrawn from the well at amount of 2-4 of volumes of pumped treatment solution and solution of ML-81B. The well is washed with process mineralised water to "clear water".

EFFECT: increased efficiency of pressure well, perforations and bottomhole zone.

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