DOWN-HOLE RELEASING DEVICE Russian patent published in 2006 - IPC E21B17/06 

FIELD: oil and gas industry, particularly to repair oil and gas wells.

SUBSTANCE: releasing device comprises upper and lower releasable parts connected one to another by lock, which may be opened by movable bush. The bush may be displaced under the action of excessive pressure created in hole annuity. Upper releasing device part is made as sub to which lock is connected. Lock is made as collet fixed with movable bush. The bush is secured to piston arranged in annular inner cavity. The cavity is hydraulically communicated with pipe string interior. The collet has many-sided slot and is connected to sub having connection thread. Lower releasing device part is made as rod with many-sided upper end to be inserted in many-sided collet slot. Lower end of the rod is provided with connection thread.

EFFECT: increased functional capabilities.

2 dwg