DEVICE FOR WELL CLEANING OF SAND PLUG Russian patent published in 2007 - IPC E21B37/00 E21B21/00 

FIELD: oil production, particularly to repair wells involved in flushing operation.

SUBSTANCE: device comprises pipe string, connection pipe sealed from below and concentrically installed in hollow body. The hollow body is provided with cylindrical head connected to lower end of hollow body. Device also has branches, which communicate connection pipe interior with sand plug creation zone, self-packing collar with clamping nut, limiter and receiver bushing provided with central channel. The bush may perform limited axial movement with respect to the body. Connection pipe has check valve arranged over branches. Outer ribs are created over receiver bushing. Cap is installed below receiver bushing and over branches so that the cap may hermetically cooperate with central channel of receiver bushing. The receiver bushing has self-packing collar and side channels located over lower seal of self-packing collar made as inflatable sleeve. Upper sleeve end is fixedly retained by means of clamping nut in air-tight manner. Limiter is secured to receiver bushing from below and encloses the body from outer body side to provide air-tight axial displacement thereof. Upper end of connection pipe cooperates with technological bushing and provides limited axial displacement thereof in air-tight manner. The technological bushing is fixed to pipe string and is provided with radial channels, which may be communicated with pipe string interior or may be sealed with connection pipe.

EFFECT: simplified structure, increased operational efficiency and reliability.

2 dwg