Correlation between eddy currents and corrosion in electric submersible pump systems

This paper introduces both stray magnetic-field and thermal analyses of electric submersible pump (ESP) motors and cables under normal and abnormal operating conditions. These abnormal operating conditions include running the electric submersible pump motor under imbalance and single-phasing. Moreover, both concentric and eccentric electric submersible pump oil well models with flat and round cables were investigated. Experimental tests were conducted on a reduced-scale electric submersible pump motor. In addition, theoretical simulations were performed using a finite-element based software package for a reduced-scale electric submersible pump motor, and a full-scale electric submersible pump motor and its power cable of flat and round types. Compared to the cases of running the motor under balanced or unbalanced conditions, the single-phasing operation of eccentric wells gives the highest localized magnetic-flux and eddy current densities, hence the possibility of localized corrosion increases. It has been found that there is a strong correlation between the eddy-current thermal effect and the severe localized corrosion of the electric submersible pump system. Therefore, it is highly recommended to use round power cables and not to operate the electric submersible pump system under single phasing conditions.