ARRANGEMENT FOR SEALING IN-TUBE SPACE WHEN LIFTING PIPES FROM WELL UNDER PRESSURE Russian patent published in 1997 - IPC

FIELD: oil and gas production. SUBSTANCE: housing of arrangement has fix-to tube members and sealing facilities with corresponding hydraulic drives. Arrangement is placed in pump- compressor pipes and pumped through to a specified depth. Under pressure developed in discharge line, fix-to tube members are forced to be inside housing. At specified depth, pressure in discharge line is dropped and in-tube sealing member is depackerized under downhole pressure. Corresponding piston is now displaced in relation to housing of fixation facilities' hydraulic drive and fixation relative to tube takes place. Fix-to-tube members move in V-shaped grooves of piston and come out of housing providing fixation of arrangement in relation to tube. After checking quality of sealing pump-compressor pipes, the latter are ready to be lifted. Owing to reasonable disposition of housing of hydraulic drive of fix-to-tube members beyond sealing members, a possibility arises to increase area of their pistons and so to increase their power and provide more reliable operation of arrangement when being set and fixed to tube even under low formation pressure. EFFECT: increased reliability. 4 dwg