DEVICE FOR BOTTOMHOLE DEPRESSION CLEANING Russian patent published in 2003 - IPC

FIELD: oil producing industry. SUBSTANCE: device includes depression chamber with separating piston and shutoff means. Depression chamber is hydraulically communicated with sludge receiving chamber provided with end receiving part. Shutoff means is made in form of shutoff valve located in lower part of sludge receiving chamber. Device is provided with appliance of hydrodynamic action in form of diffuser-converging tube and flexible ball. Appliance of hydrodynamic action is installed between separating piston and sludge receiving chamber separating piston is of differential type. End receiving part of sludge-receiving chamber is made in form of tubular spider. Additionally built-up above separating piston is valve- plug. With appliance retrieved to surface, valve-plug communicates internal cavity of tubing with well annulus. EFFECT: higher efficiency of cleaning of deep wells and reduced adversive effect of hydraulic impact on well structure.