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 a water-saturated zone below the oil-saturated zone of the formation and thickness of the non-permeable natural interlayer of less than 3 m there cut is some part of the casing string from the bottom of the non-permeable natural interlayer to the roof of the oil-saturated zone of the formation, and the well shaft at that interval is enlarged. After that, a setup consisting of a cutter with teeth and holes, a shank and an attachment assembly is assembled on the well head in an upward direction. With that, the shank is made in the form of pipe with the diameter that is smaller than the casing string diameter. A check valve is installed on the lower shank end. The shank length is chosen so that it is equal to distance from the mine face to roof of the oil-saturated zone of formation plus two metres. The assembled setup is connected by means of a left-hand adapter to a filling pipe string and lowered to the casing string of the well till the cutter teeth are borne against the mine face. Cutter teeth are directed to the side opposite to rotation direction of the filling pipe string at detachment of the filling pipe string from the shank. Rotation of the filling pipe string is performed from the well head in a clockwise direction through 8-10 revolutions and detachment of the filing pipe string from the shank is performed. The filling pipe string is raised by 1.5 m; insulating compound is pumped to the filling pipe string and pumped with forcing-through liquid to the tubular annulus; brought to the shank head; the filling pipe string with the left-hand adapter and the attachment assembly is removed from the well, and the insulating compound is left till it is cured. Microcement is used as an insulating compound. After microcement is cured, drilling of the check valve is performed from the inner space of the shank and excess microcement is removed from the shank. Then, the well is brought into development as a production well for extraction of the product from the oil-saturated zone of the formation or as an injection well for pumping of liquid to the water-saturated zone of formation.

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

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