DEVICE FOR TREATMENT OF BOTTOM-HOLE FORMATION ZONE Russian patent published in 1995 - IPC

FIELD: oil producing industry. SUBSTANCE: device for treatment of bottom-hole formation zone has tubing 1 with shoe 2 provided with bushing 3 and cone nozzle 4 connected with bushing and locked with shear screws 5. Upper part 6 of bushing 3 is conical to receive mating protected conical thread from load 7 of well equipment 9 included into casing string 9. Shoe 2 is connected with tubing 1 by means of threaded joint 10. Bushing 3 is made of chemically disintegrated material less hard than material of well equipment. Installation of bushing on the protected conical thread of well equipment excludes impact loads to prevent premature failure of well equipment. EFFECT: prevented damage to internal thread of well equipment in round-trip operations and prevented seizing of bushing by safety valve body. 2 cl, 3 dwg