HORIZONTAL WELL OPERATION METHOD Russian patent published in 2015 - IPC E21B43/00 E21B43/32 

FIELD: oil and gas industry.

SUBSTANCE: invention relates to the oil industry and may be used in the operation of a horizontal well. According to the method well operation is performed. A pipe string is run down to the horizontal well. An insulating material is injected through the pipe string to a water-inflow interval of the productive formation. Oil is extracted until the horizontal well is flooded. Under the main borehole along the boundary of the oil-water contact an additional borehole is drilled from the horizontal well per 50 m longer than the old hole. The coil tubing is run down to the well complete from below with a hydraulic whipstock and a screen, which openings are covered hermetically by a hollow bushing. The process fluid is injected to the coil tubing thus creating an excess pressure. Simultaneously the coil tubing is moved down until it gets to the additional borehole. The coil tubing is run down up to the bottomhole of the additional hole. At the wellhead a top cementing plug is set into the coil tubing. An excess pressure is created in the coil tubing above the top cementing plug and the hollow bushing is moved thus opening the screen openings. Microcement grout is injected through the coil tubing and flushed to the additional hole and the bottomhole zone. Simultaneously the coil tubing is pulled out for the purpose of additional hole filling with the microcement grout. Flushing of the microcement grout is stopped when pressure increases in the coil tubing up to a permissible value. The coil tubing is pulled out from the well and the process is withheld for cement setting and hardening. The additional hole is cut off from the old hole by setting a bridge plug in a kickoff interval at the inlet to the offshoot. A pump is run down at the process pipe string to the old hole of the horizontal well and operation of the horizontal well is started. At water encroachment into the produced product the process pipe string with the pump is pulled out from the well, a geophysical study is performed and a water-producing interval is indentified in the horizontal well. The water-producing interval in the old hole of the horizontal well is isolated.

EFFECT: increased efficiency of the method due to the complete exhaustion of oil reserves from the productive formation notwithstanding the drawdown value.

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