PROCEDURE FOR PERFORATION OF SECTION OF PIPE IN WELL AND DEVICE FOR ITS IMPLEMENTATION Russian patent published in 2011 - IPC E21B43/11 

FIELD: gas-and-oil producing industry.

SUBSTANCE: procedure for perforating section of pipe in well consists in supply of electrolyte, mainly water solution of chloride salts of alkali and/or alkali/earth metals on wall of perforated pipe, also, electric current feeding electrochemical cell is supplied to device via cable. A metal pipe functions as an anode of the electrochemical cell. Further the procedure consists in electrochemical anode perforating a pipe section. Direct current in the range from 5 A to 50 A, or alternate current with an effective value in the range from 5 A to 50 A is supplied to the device through the cable. Direct voltage from 5 V to 50 V or pulse unidirectional voltage with dc component from 5 V to 50 V and pulse repletion rate from 60 kHz to 1000 kHz is fed to electrodes of the electrochemical cell. Notably, temperature of electrolyte is maintained from -10°C to +80°C. The device for implementation of the procedure consists of a unit for securing the device to pressure string, of a compensator of pressure string length, of a wedge contact unit including telescopic contact wedges and a hydraulic piston-pusher of the electric unit. Simultaneously, the contact unit functions as an upper centraliser and holder of the device in a working position. The device includes the electric unit with a sealed cable entry. A transformer, block of current converter, anode, cathode and a lower centraliser are arranged in the electric unit. The device contains dielectric insertions electrically isolating units of the device from each other, a spring loaded back valve, process recording sensors, and a pipe perforation control sensor located on an upper removable cathode equipped with a channel for electrolyte drain. The cathode is rigidly fixed on a cathode case outside covered with dielectric layer. The device is made with at least two removable cathodes.

EFFECT: partial electrochemical perforating section of pipe in well.

6 cl, 4 dwg