DEVICE FOR RELEASING STRING FROM WELL Russian patent published in 2011 - IPC E21B31/107 

FIELD: gas-and-oil producing industry.

SUBSTANCE: device consists of damper between lifter and generator of vertical pulses tied with string from below. The damper corresponds to a vertical pressure tight cylinder with a piston, internal cavity of which under the piston is filled with gas. The generator is made as a tubular case consisting of serially connected power cylinders; on top the tubular case is coupled with a rod of the damper piston. The cylinders are equipped with power pistons serially tied by means of hollow rods so, that their sub-piston cavities are inter-communicated and are communicated with a piston valveless pump via a distributor and a safety valve. A lower rod of the power piston is blinded from beneath and is connected with the string. The distributor consists of a cylinder case with two chambers divided with a partition. The safety valve is installed between the distributor and the piston valveless pump; it communicates this branch with a buffer reservoir. Between the lower rod of the hydro-cylinder and the string there is installed a T-branch connected with an additional pump with a reservoir, which communicates with annular space of the well. Over a point of freeze-in the string is equipped with a vibrator of radial action consisting of a hollow cylinder encasing a rod with pass channel and of a seat positioned in the pass channel of the rod; a ball is inserted in the seat. The cylinder is made eccentric, centre of gravity of which is set off relative to axis of the device.

EFFECT: increased efficiency of operation.

3 dwg