DEVICE FOR WELL CLEANING Russian patent published in 1996 - IPC

FIELD: operation and repairs of wells; applicable in cleaning of wells from cuttings, sediments and bridgings formed by cuttings. SUBSTANCE: device for well cleaning has body connected to pipe string and hollow rod with section with perforations. Hollow rod is installed in body for limited axial motion. Device has case. Body, hollow rod and case have respective supporting circular projections that provide for their axial motion. Body accommodates spring-loaded valve. Section of hollow rod with perforations is isolated from body hollow in the initial position of the device. Body has tail provided with working tool, for instance, with wing. Installed in the lower part of pipe string is sealing member closing side hole in pipe string. If required, side hole is opened by using falling member. When removing, for instance, cuttings bridging, working tool breaks bridging material and hollow rod extends into body hollow. Fluid with cuttings through opened spring-loaded valve enters body hollow and through perforated holes to pipe string. Working tool individually passes the surface with bridging by moving down and removing it. Then, valve closes, when pressure difference disappears, or when body with tail move to their extreme lower position. EFFECT: increased flow of cuttings into device and more efficient removal of bridgings. 3 cl, 2 dwg