DOWNHOLE PIPE DRIFT Russian patent published in 2003 - IPC

FIELD: underground repairs of wells designed for making holes in pipe walls for communication of pipe cavity with ambient medium. SUBSTANCE: downhole pipe drift has cylinder and hollow filled with fluid body with side channel accommodating piston with working member, rod installed in hollows of body and cylinder for axial motion. Hollow plunger installed in cylinder hollows is connected with rod having shear member and forms rod and working chambers in cylinder. Drift has sub whose channel communicates working chamber with ambient medium and also locking member closing sub channel, and anchor installed in sub for axial motion and connected with sub by shear member. Novelty consists in that installed in body hollow is flexible deformable member for locking of rod relative to body. Locking member in sub channel is made in the form of plug provided with sealing member installed for opening to working chamber and rigidly connected with anchor. EFFECT: higher reliability of downhole pipe drift and extended its functional potentialities. 3 dwg