METHOD FOR DESTROYING PIPE PORTION IN A WELL AND DEVICE REALIZING SAID METHOD Russian patent published in 2004 - IPC

FIELD: oil and gas extracting industry. SUBSTANCE: method is realized by a device, which has composition in form of pipe-shaped housing with the body inside and with an aperture for outlet of electrolyte. Also provided are packing glands, anode and ring cathode. Device is also provided with bus and centrators. Pipe-shaped housing has connecting sleeve for fixing to tubing string. Body is water-tight, has no less than two sections and is placed on centering bushings. Packing glands are made in form of bowl- shaped elastic glands. Body is provided with water-tight input of power cable, water-tight outputs onto ring cathode and anode. Water-tight output onto ring cathode is placed on the housing and isolated thereof. Length of cathode is determined by length of pipe portion being destroyed. Anode output passes through the bus onto centrators, which simultaneously have function of contacts to the pipe. Packing glands are located with their bowls turned upwards above and below pipe portion being destroyed for forming an electrochemical cell together with ring cathode and inner pipe wall. Body sections are equipped with packers of, for example, labyrinth type. Electrochemical cell is connected to the space between body and housing through aperture for electrolyte outlet for allowing pumping of electrolyte. Destruction of pipe portion is performed by supplying electrolyte onto pipe wall. Impulse electrical current is fed to device along power cable with voltage between 0.1 and 1000 volts. Feeding of electrolyte is performed with constant pumping thereof from the surface along tubing string through ring space between the body and pipe-shaped housing and further into electrochemical cell. Process parameters are kept in following limits. Temperature is 0-200 centigrade, electrolyte pressure is 0.1-40 megapascals. Electrolyte pumping is stopped, when electrical current stops flowing, which occurs after full destruction of pipe portion. EFFECT: increased effectiveness of electrochemical anode pipe metal dissolution and assured full dissolution of pipe portion being subject to removal. 2 cl, 2 dwg, 1 tbl