DOWNHOLE CUTOFF VALVE Russian patent published in 2013 - IPC E21B34/08 

FIELD: oil and gas industry.

SUBSTANCE: valve consists of a body with valve unit in it, actuating and fixing mechanisms and connections. The valve is made as a hollow cylinder with holes in the body in the upper and lower parts so that liquid could enter from areas over and under the valve. In the upper part there is piston connected through rod with fixing device, which in its turn is connected to the valve unit. Fixing device consists of two cylindrical parts - crown and fixture with nicks at outside surface; they have opposite but-end teeth with camming surfaces that provide axial barring of the fixture and installation in cage with internal nicks and it ensures multiple actuation of the device. Self-aligned valve and metal to metal seal ensure reliable sealing. Thus necessity of well killing by kill mud is excluded during downhole treatment.

EFFECT: improvement of sealing process and separation of downhole space.

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