DEVICE FOR SAND PLUG REMOVAL FROM WELL Russian patent published in 2007 - IPC E21B37/00 

FIELD: oil production industry, particularly current well repair and well workover associated with well flushing to remove sand plugs, silt, scale and so on.

SUBSTANCE: device comprises pipe string, hollow body, sealed nipple concentrically installed in hollow body provided with self-sealing collar with lock-nut and cylindrical head. Device also has branches to communicate nipple interior with sand plug formation zone, stop and mounting bush with central channel, which may perform limited axial movement relatively hollow body. The nipple is closed from top thereof. Hollow body additionally has seat located inside upper hollow body part and with short and long axial turnings located in lower part thereof and connected with each other through radial groove from below. Bush is concentrically inserted in hollow body from outer nipple side and is connected with the nipple through branches. Mounting bush top is fixedly fastened to hollow stem. Mounting bush bottom is secured to hollow head installed in hollow body in air-tight manner and provided with pin. Hollow cup is arranged in central channel of mounting bush over nipple. Hollow stem has valve cooperating with hollow body seat. Hollow stem top is slidably connected with bush secured to pipe string and provided with radial channels. Radial channels may be closed with hollow stem during upward stem movement.

EFFECT: increased reliability and operational efficiency of device usage in wells with lost-circulation formations having low formation pressure.

3 dwg