METHOD OF FORMATION ISOLATION WITH CEMENT-SILICATE MUD Russian patent published in 2014 - IPC E21B33/138 C09K8/467 

FIELD: oil and gas industry.

SUBSTANCE: method of formation insulation with cement-silicate mud involves injection into a formation well bore zone of cement mud with hardener. Plugging is performed by cyclic successive-alternating injection into a well of sodium silicate solutions (mass fraction from 20 to 45%, silica module over 2.5) with wood dust filler (mass fraction not above 3%) and cement hydrated with water solution of sodium silicate (mass fraction not more than 5%) with ratio to cement equal to 0.5. At that, sodium silicate and cement solutions during pump-in are separated by buffer - fresh water in volume of 10 to 15% of volume of process pipes lowered into the well. Volume ratio of cement mud and sodium silicate solution is 0.3 to 0.7.

EFFECT: formation insulation quality improvement regardless of formation permeability degree and sizes of conducting channels, shortening of terms of drilling and servicing of difficult wells, increase of production of hydrocarbon stock.

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