OUTER DRIVE DOWN CASING SPEAR Russian patent published in 2008 - IPC E21B31/18 

FIELD: oil and gas industry.

SUBSTANCE: invention refers to boring and capital repair of holes in oil and gas industry, in particular to the finger grip. The casing spear contains a bushing with the internal pass, the bearing cage with an internal helical conical surface and with the screw-shaped shoulder of the hole, installed in the bearing cage with possibility of axial movement the gripping spigot with a persistent screw-shaped part, a guide ring with a dog driver, motionlessly installed in the bearing cage. On an outer surface of the gripping spigot the helical conical surface is executed, and on internal - screw catcher thread. Between the bearing cage and a bushing the hollow tie-rod and the guiding cage are installed. The top of the bearing cage is rigidly linked to bottom of a hollow tie-rod. In the top of the bearing cage at the bottom butt end of a hollow tie-rod the ring- shaped dog is executed with possibility of landing to the top butt end of a prominent ring-shaped member on a body of taken tubes. In the top of a hollow tie-rod the cylindrical heel is executed. In the bushing pass in the initial point the travelling valve is installed with possibility of axial movement upwards is installed. The bottom of the guiding cage and a central part of a hollow tie-rod are linked among themselves by the joint that is flexible in an axial direction. The outer surface of a hollow tie-rod and an internal surface of an opening in the bottom of the guiding cage are executed in a cross-section, for example, in the octahedral form. Minor diameters of passes are executed more lager than diameter of the broken off tube. As result it is efficiency upgrading of cleaning up of taken tubes and reliability of tubes gripping.

EFFECT: efficiency upgrading of cleaning up and reliability of tubes gripping.

5 cl, 11 dwg