METHOD FOR FLUSHING CLAY-SAND OR PROPPANT PLUG OUT OF A WELL Russian patent published in 2023 - IPC E21B37/00 

FIELD: oil and gas industry.

SUBSTANCE: invention is related to flushing compacted clay-sand or proppant plug out of a well. The method includes lowering the device into the well on a tubing string above the plug, injecting flushing fluid lifting the liquid through the annular space of the well, discharging a ball from the wellhead into the tubing string, performing a hydrodynamic effect on the plug after the ball is seated in the landing saddle by pumping fluid through the tubing string, switching the flushing direction and lifting loosened solid plug deposits along the tubing string by pumping fluid through the annulus under pressure. Simultaneously with the hydrodynamic effect on the plug, cavitation is carried out, generated by a device installed on the tubing string, made in form of a hollow cylindrical body with an oblique cut, having one seating saddle for landing the dropped ball. One tier of nozzles is radially fixed in the seating saddle, the nozzles are directed downwards at an angle of 20-3° to the axis of the hollow cylindrical body. The body and seat form a central flushing channel. The nozzles have the form of an internal flow channel, which provides the generation of cavitation outflow.

EFFECT: efficient destruction of the plug is ensured due to the continuous impact of intense elastic vibrations with destruction of the particles of the plug and facilitating their removal to the surface.

3 cl, 1 dwg, 1 tbl