Induction vs. Permanent-Magnet Motors for ESP Applications

Abstract

Summary In this paper we provide an overview comparing induction motors (IMs) and permanent-magnet motors (PMMs) for electrical-submersible-pump (ESP) applications. The design and performance differences of the two types of motors are compared and discussed. The PMM advantage and unique applications are highlighted. The requirement of a different control strategy to operate a PMM is described. Some key safety aspects that field engineers need to be aware of with PMMs are also addressed in this paper. The information we present includes a literature review and the latest research and development results. We cover the operating principles of the IM and the PMM, selection of permanent-magnet materials, operating frequency, stator windings, and magnetic poles. PMMs offer better efficiency, higher power-factor performance, and compactness. Ideal applications include slim-well applications, through-tubing rigless deployment, Y-tool completion, and electric-submersible-progressive cavity pumps (ESPCPs). We will also shed some light on why conventional IMs cannot be used to drive ESPCPs directly without speed-reduction gearboxes. It is very likely that the use of PMMs will increase for ESP applications in the near future, and this will require engineers to acquire a basic understanding of this technology. This paper intends to provide a high-level comparison between IMs and PMMs in the ESP industry.

Rigorous review of electrical submersible pump failure mechanisms and their mitigation measures

“…• Proper material selection can prolong the life of the ESP assembly significantly by avoiding component failures. • Electrical failures are one of the most severe forms of ESP failures since they can result in immediate opera- (Xiao et al 2020;Ye and Wilcox, 2018;Tiofiolo et al 2018;Xiao and Lastra, 2019;Pino et al 2015) (Ye et al 2019;Medina et al 2012)…”

“…Component breakage can cause malfunctioning, and failure, of components downhole the most severe of which is ESP and motor failure due to impeller or rotor breakage, respectively. Another major complication due to component breakage is partial loss of downhole components that may be completely severed from the string (Xiao et al 2020;Ye and Wilcox 2018;Tiofiolo et al 2018;Xiao and Lastra 2019;Pino et al 2015).…”