DEVELOPMENT METHOD OF WATER-FLOODED OIL DEPOSIT Russian patent published in 2014 - IPC E21B43/32 

FIELD: oil and gas industry.

SUBSTANCE: method involves drilling of a deposit with production wells crossing a formation consisting of a water-saturated zone separated with a non-permeable natural interlayer with an oil-saturated zone, lowering of a casing string with further formation perforation, investigation of its water-oil saturation and their deposit intervals, dimensions of non-permeable natural interlayer, creation of a screen from an insulating compound, which separates water-saturated zone of the formation from oil-saturated zone, cutting of some part of the casing string, enlarging the well shaft at that interval; filling of the enlarged interval of the well shaft with insulating compound, drilling of insulating compound after the insulating compound hardening. At arrangement of water-saturated zone below oil-saturated zone of the formation and at thickness of the non-permeable natural interlayer of more than 3 m, some part of the casing string is cut from the internal of 1.5 m below the roof of the non-permeable natural interlayer and up to the interval of 1.5 m above the bottom of the water-saturated zone of the formation. The well shaft is enlarged at each interval. A setup consisting of a shank and a hydraulic disconnector is assembled on the well head in an upward direction. The shank is made in the form of pipes with outer diameter of less than inner diameter of the casing string. A check valve is installed on the lower end of the shank with possibility of its opening or closing under action of excess pressure, and a filter is installed below it. The shank length of chosen with the size of not less than distance from the mine face up to the interval of 1.5 m below the roof of non-permeable natural interlayer. The assembled setup on the filling pipe string is lowered to the well till the lower end of the shank is borne against the mine face. A hydraulic disconnector is actuated; after that, the filling pipe string is raised to the height of 1 m and lowered; then, an insulating compound is pumped via the pipe string and the shank and the insulating compound is forced through by pumping of forcing-through liquid to the pipe string through the check valve opened under action of excess pressure and the filter of the shank to tubular annulus and brought to the shank head. The filling pipe string with the hydraulic disconnector is removed from the well and the insulating compound is left till it is cured. Microcement is used as an insulating compound. After the insulating compound is cured, drilling of the insulating compound and the check valve is performed, and drill products are removed from the shank by flushing.

EFFECT: improving development efficiency owing to excluding behind-the-casing flows; reducing labour intensity and duration of the method.

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