METHOD FOR ENHANCED OIL RECOVERY FOR DEPOSIT PENETRATED BY HORIZONTAL WELL Russian patent published in 2015 - IPC E21B43/16 E21B43/32 

FIELD: oil and gas industry.

SUBSTANCE: according to the method the well is operated until produced product is watered. The pipe string is run down to a horizontal well. The pipe string is reinforced in the horizontal well by injection of cement grout. Inner space of the pipe string is cleaned from residues of cement grout. Geophysical survey is performed and water-saturated intervals penetrated by the horizontal borehole are identified. Water-saturated intervals are perforated in sequence from the farthest end of the bottomhole to the wellhead. Oil is extracted until the interval is watered. The watered interval is isolated and oil is extracted from the next interval. At that for the purpose of the perforated watered interval isolation a section of the pipe string in the horizontal borehole is cut from the wellhead side in regard to the watered interval. The cut section of the pipe string is cleaned out from residues of broken cement stone. Then at the wellhead top-bottom an assembly is made consisting of a plug, water-swellable packer, a tube and a drillable packer with setting tool. The assembled assembly is run in to the horizontal well at the pipe string until the water-swellable packer is set opposite the cut out section of the pipe string. The drillable packer is set in the pipe string and the process string is removed from the well with setting tool. Thereupon the next oil-saturated interval is perforated and oil extraction is continued until water cut of extracted oil. Then the above operations are repeated starting from cut-out of a section in the pipe string of the horizontal borehole and completing with removal of the process pipe string with setting tool from the well.

EFFECT: improved quality of isolation for flooded intervals.

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