DEVICE FOR EXTRACTION OF LONG-LENGTH PIPE Russian patent published in 2016 - IPC E21B31/20 E21B31/18 

FIELD: oil and gas industry.

SUBSTANCE: invention can be used for emergency extraction column or sections of long-length pipe from well. Device includes a hollow housing, connected through a cup with an adapter. In axial channel of cup there is a central core provided with a cone with a conical surface on lower end. Annular piston is rigidly coupled with core and forms with hollow housing a chamber in which there is a spring with a support on annular piston and cup. Inside housing under annular piston there is a conical piston with formation of a circular cavity, permanently hydraulically connected with radial holes in body of annular piston with axial channel of core. Housing in bottom part comprises an inner taper surface whereon rests outer gripping element in form of plates with T-like ledges. Under conical piston there is a spacer sleeve in which there are T-shaped grooves in which T-shaped ledges of plates are arranged, on inner surface of which there is a notch. In body of spacer sleeve on inner surface there is an annular groove to receive a split spring ring, retaining plates. Under conical piston in housing there are drain holes. On cone there is an inner gripping element in form of separate plates with a notch and outer annular groove in middle part, in which there is a split spring ring for their pressing simultaneously to conical piston and to conical surface of cone on central core. Outer and inner gripping elements are installed with possibility of axial and radial movement.

EFFECT: higher reliability of gripping, enabling adjustment of gripping force and obtaining information on operation of device.

1 cl, 3 dwg