Abstract
The induction motor has dominated the global ESP market for decades; however permanent magnet motors (PMM) are gaining acceptance for use in artificial lift. Some PMM vendors have made claims of 20% - 30% reduction in electric operating costs, improved efficiency, and wider applications for today's challenging wells. This paper describes a testing program conducted to understand the characteristics of PMM's, to verify vendor claims and evaluate how to leverage this downhole motor technology to reduce operating expenses.
Two International Oil Companies (IOC's) partnered to sponsor a Motor Evaluation Test (MET) program from 2014 - 2015. A motor test protocol was drafted, and ESP motor sizes of 100 HP 450 series were targeted for evaluation. Six ESP vendors agreed to participate, contributing their motor and variable frequency drives (VFD). Four induction motors and four permanent magnet motors, each partnered with the vendor supplied VFD, were evaluated. The objective of the testing was not to differentiate the vendor's products, but to understand the differences in the motor technologies. An independent third-party witness was selected from industry experts to supervise the testing, ensuring to follow the test protocols, manage data security, and test validation. The results were analyzed, documented and reported to vendors by the sponsor companies.
The PMM was found to be a cost competitive alternative to the IM for equivalent ESP installations with a VFD. In existing fields, a phased-in approach to replace failed IM with PMM may be economic. For new field developments the PMM offers the benefits of power savings and use in challenging well bore configurations. Alternatively deployed (AD) ESP with PMM may offer reduced well intervention cost as well an improved ability to pass through build angles that would challenge the longer IM system.
