PULSED CURRENT CATHODIC PROTECTION OF WELL CASINGS

Electric pulses of several hundred volts, applied for very brief perio ds of time, several thousand times per second, are more effective and economical than conventional steady-state DC currents in protecting de ep and/or close-spaced well casings against external corrosion. More u niform current distribution, greater depth of protection, reduced stra y current interference, and smaller anode bed requirements are the mai n benefits of pulsed technology. Operating principles, equivalent elec trical circuits, design considerations, and field cathodic protection logging experience is reviewed.