DEVICE FOR CLEANING WELL STRAINERS Russian patent published in 1998 - IPC

FIELD: oil and gas production industry. SUBSTANCE: this basically relates to building and operation of oil and gas wells in loose-cemented reservoirs, and particularly to freeing strainers in operating wells from clay sedimentation. Device has hollow body with side holes. Installed at one side of body is cylindrical threaded bush, and installed at other side of body is stepped-like bush. Smaller diameter cylindrical surface of stepped-like bush is threaded. Body at side of upper end face is provided with tail-piece which is threaded, at side of lower end face it has threaded hole which is located along its axis. Located on lower end face of stepped-like bush is releasing unit which is made in the form of stopper provided with lock. Stopper can be provided with axial through-hole which can be closed with ball. Located on body tail-piece and on smaller diameter cylindrical surface of stepped-like bush are flexible members. Made in body below tail-piece are side holes. In assembly, these side holes are located between upper and lower flexible members. Length of smaller diameter thread of stepped-like bush and tail-piece of threaded hole in body and bush is by 15-20 mm shorter and depends on value of cylindrical clearance between inner side of strainer and outer surface of device body. Device allows for maintaining operating output of oil or gas well at required level without extracting strainer for its cleaning due to complete washing of filtrating part of well strainer. In addition, bottom hole of well which is washed off from sand plug by means of aforesaid device allows for removing lift pipe string from well at any time at repair operations. EFFECT: higher efficiency. 2 cl, 2 dwg