ISOLATION METHOD OF WELL TROUBLESOME ZONE WITH CARBONATE BASINS Russian patent published in 2013 - IPC E21B33/13 C09K8/50 

FIELD: oil and gas industry.

SUBSTANCE: method consists in series pumping to a well of portions of water solution of a structure-forming reagent and a structure former, which are separated with fresh water bank. Water solution of the structure-forming reagent and the structure former is forced through to isolated interval by pumping of displacement fluid. First, water solution of hydroxochloric aluminium is pumped to the formation and left for the time period of reaction with carbonate basin. Pumping and forcing-through of water solution of structure-forming reagent and structure former is performed in a pulse mode. After pumping of every 0.5-1.5 m³ of displacement fluid to the isolated interval is performed, periodic relief of the formation excess pressure is performed by opening the well with outflow of displacement fluid via the tubing through a nozzle to a ground reservoir. Then, pumping of displacement fluid is continued after its outflow ends. At each next relief the pressure value, by which the relief is performed, is increased by 0.4-0.6 MPa.

EFFECT: improving isolation efficiency of water influx zones in the well with carbonate basins owing to reducing intake capacity of a troublesome zone, improving mixing of components of waterproof composition and creation of a more reliable waterproof screen.

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