DEVICE FOR UNSCREWING PIPES IN WELL Russian patent published in 1999 - IPC

FIELD: oil and gas production industry. SUBSTANCE: device relates to drilling technology and can be used in liquidations of breakdowns connected with jamming of pipes during drilling or repair. Device has hollow rod and hydraulic anchor installed for possible axial displacement of its body on hollow rod. Motion converting mechanism is made in the form of "screw-nut" transmission for possible interaction with body and catcher. Screw is rigidly connected with hollow rod. Nut is provided with freewheeling clutch adapted for transmitting torque to body. Hydraulic anchor and catcher are interconnected by setting housing for possible rotation and positive axial movement. Catcher is made in the form of hydraulic anchor located on hollow rod and adapted for axial displacement. For operation, device is lowered into well, and hydraulic anchor is installed against one casing pipe, and catcher is installed against other casing pipe. At raising pressure, slips of anchor and catcher come into engagement with casing pipes. By lifting string of pump-compressor pipes connected with hollow shaft, nut is rotated by screw. This leads to rotation and unscrewing of upper pipe. Freewheeling clutch allows for returning screw to initial position by lowering of pump-compressor pipes. Application of aforesaid embodiment of device allows for creating facility which is simple in design and ensuring unscrewing of casing string for subsequent extraction from well. EFFECT: higher efficiency. 1 dwg