CASING SPEAR Russian patent published in 2009 - IPC E21B31/16 

FIELD: oil and gas industry.

SUBSTANCE: invention is related to oil and gas industry and is intended for withdrawal of emergency pipes from wells. Device comprises hollow body with internal cone surface in lower part, sub installed in hollow body, central core with aligning cone, coaxially installed in hollow body and having common axial channel, external gripping element and internal gripping element installed in hollow body with the possibility of axial displacement, slotted nut that is rigidly fixed to internal cavity of hollow body in its upper part and connected to central core by means of slotted joint that provides for rotation of hollow body together with central core relative to device axis, distance sleeve installed on external gripping element, cone piston installed on central core under slotted nut and resting on distance sleeve. Hollow body in lower part contains external aligning cone with cutters on its internal cone surface. Central core in its upper part is rigidly connected to sub installed with the possibility of rotation, and has annular bulge with radial holes that provide for creation of annular cavity between slotted nut and cone piston, and this cavity is hydraulically connected to common axial channel. External gripping element is installed in internal cone surface of hollow body and is arranged in the form of split bushing with ribbed internal surface and cone external surface. Internal gripping element is installed on central core between cone piston and aligning cone and is arranged in the form of split bushing with ribbed external surface and internal surface in the form of meeting upper and lower cones. Surface of upper cone is responsive to external cone surface of cone piston, and lower one - to external cone surface of aligning cone. Aligning cone is equipped with cutters in lower part.

EFFECT: increased operational reliability and expansion of technological resources.

1 dwg