WELL HEAD DEVICE FOR TUBING STRING RELEASE FROM WELL Russian patent published in 2010 - IPC E21B31/107 

FIELD: oil-and-gas industry.

SUBSTANCE: well head device for tubing string release from a well includes a vertical impulse generator and a damper, installed between a lift and the vertical impulse generator. At that the damper executed as a vertical sealed cylinder with a piston, which internal cavity filled with gas, and the generator executed as a tube case with additional cylinder with a ring piston installed on the top, interacting from the bottom with a stringed balance, executed with ability of reciprocate displacements along the tube case. Cavity over the piston executed with ability to connect to a pump, equipped with a buffer tank, through a distributor, consisting of a cylindrical case with two chambers, which connected with each other with channel, created in the distributor wall, and a drive rotating wall, equipped with straight valve for liquid supply from a pump and a return valve for liquid a cutting, periodically connecting with mentioned above channel.

EFFECT: simple design and the tubing string release from a well efficiency increase due to upward directed force increase.

2 cl, 2 dwg