DEVICE FOR SEALING LINER IN CASING STRING Russian patent published in 2024 - IPC E21B33/14 E21B23/06 

FIELD: mining.

SUBSTANCE: invention relates to a device for sealing a liner in a casing string. Device contains a coupling for connection of the device to the transfer pipe string, a housing, a liner, a shoe with a valve unit, a hole opened under action of hydraulic pressure. Coupling is connected to the housing by a detachable device in the form of balls inserted into the radial holes of the coupling and interacting from the outside with the inner recess of the liner housing, and from inside supported by a seat under a releasable ball with an external groove, which is fixed by shear elements in an upper position and made with the possibility of limited downward movement after destruction of the shear elements until the balls interact with the groove and the balls come out of interaction with the annular recess of the housing. On the upper end of the liner housing there are slots for external protrusions on the coupling surface. Inside the housing on shear elements there is a suspended cementing plug with a central through channel, a seating cone from below for fitting into the seat of the stop ring, and a stop device from above for seating and fixing a small displacement plug. Uncoupling device is made integral with the housing with inner diameter, which allows tight insertion and fixation of the packer shaft with sealing elements and locking rings installed on the shaft and made for grooves on the inner surface of the housing. Below the sealing elements there is a bushing fixed with a shear element on the shaft with the possibility of movement along the shaft and compression of the sealing elements when the packer is fitted into the housing. From above, the packer is connected to the pipe string by means of a shear element, which enables to extract the pipe string with the sub after seating and fixation of the packer into the housing; at that, the inner diameter of the packer is equal to the inner diameter of the liner casing pipes.

EFFECT: providing liner sealing at high external pressure during operation, as well as exclusion of probability of end part deformation during lowering of pumping equipment in directional and horizontal wells.

1 cl, 3 dwg