UNLATCHING JOINT Russian patent published in 2011 - IPC E21B17/06 

FIELD: mining.

SUBSTANCE: unlatching joint includes upper and lower reducers which are connected to each other by means of fixture, and vessel with corrosive fluid in relation to fixture located below bottom part of the vessel. At that, joint is equipped with seat for waste valve, which is movable in axial direction and fixed in initial position against axial movement with a stop, and hammers for depressurisation of the vessel. Seat body has annular groove on outer surface forming together with the upper reducer a cavity for arrangement of vessel with corrosive fluid to protect it against the contact with the lowered equipment. At that, each hammer is rigidly fixed relative to its upper reducer and has faceted outer surface, and bottom part of vessel has annular section which has plane of weakness, which is located opposite hammers.

EFFECT: improving reliability and efficiency of operations during elimination of accidents relating to sticking of tools in the well.

6 cl, 3 dwg