DEVICE FOR STAGED CEMENTING OF WELL Russian patent published in 2011 - IPC E21B33/14 

FIELD: construction.

SUBSTANCE: device for staged cementing of a wall comprises a hollow body with cementing holes, outlet holes, a shear thrust screw, at least one, installed above outlet holes and protruding into the body, a differential bushing with a hollow shear pin, fixed in the body by a shear element, at least one, covering the cementing holes of the body and forming a circular chamber with it, capable of hydraulic connection with the body cavity after shearing the hollow pin, the upper bushing with a seat and a fixator of its final position, fixed in the body by a shear screw, at least one, and installed above the differential bushing, an adapter that enters partially into the body and forming with the latter and the lower end of the differential bushing a circular cavity in the zone of the shear thrust screw, communicated with the well space via outlet holes. Besides, the shear thrust screw is made with the possibility of shearing from pressure providing for hydraulic disturbances in the well liquid behind the body to damage its stagnant zones.

EFFECT: increased reliability of device operation with provision of a solid cement ring in a well in the device zone.

2 cl, 1 dwg