DEVICE FOR WELL DEPRESSION CLEANUP Russian patent published in 1997 - IPC

FIELD: oil producing industry; may be used in capacity of process equipment for cleaning of bottom-hole formation zone and well bottom from cuttings, sand, wax, resins and other sediments difficult to remove by flushing. SUBSTANCE: device has depression chamber with plug valve and cuttings receiving chamber with separating piston installed on extensible retainers. Installed in separating piston is percussive rod with shear pin. Packer is installed between cuttings receiving chamber and container for interconnection with chamber body. Packer hollow body is secured to chamber body by means of shear pin. Container has locking valve and section with receiving holes has longitudinal stiffening ribs. Container body on the section with receiving holes is made from shaped branch pipe. Receiving holes are located in depressions between longitudinal stiffening ribs. When axial load is built up, pin is sheared and packer seals the annular space. Percussive rod shears its pin to free extensible retainers. pressure differential is built up across separating piston and implosion effect occurs. Cuttings receiving chamber is filled with cuttings and fluid. Locking valve closes. In lifting plug valve operates. EFFECT: higher efficiency of cleaning deep wells, reduced negative effect of hydraulic impacts onto device design and casing with cement ring. 2 cl, 2 dwg