PROCEDURE FOR SELECTIVE SHUTOFF OF WATER-ENCROACHED SECTIONS OF OIL RESERVOIR Russian patent published in 2014 - IPC E21B33/138 C09K8/504 

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil producing industry, and namely to methods of water influx limitation in oil producers and alignment of injectivity profile in injectors. Procedure for selective shutoff of water-encroached sections of oil reservoir includes injection of gel-forming compound to the reservoir, flushing of the above compound to the reservoir and break in the process. At that 5-20 wt % of sodium metasilicate to the above compound and 3-9 wt % of chromic potassium alum as the initiator of gel-forming process and water up to the remaining volume. In 3-4 hours upon injection of water shutoff compound injection of alkali solution is performed in order to recover permeability of oil-saturated intervals. Then break in process is taken for 12-18 hours, thereafter operation of the well is started again.

EFFECT: reduction in associated water production due to shutoff of producers or increase in oil recovery efficiency due to growth of sweep efficiency and connection of oil-saturated and low-permeable interlayers due to redistribution of injected water flows during treatment of injectors.

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