Successful Permanent Magnet Motors Performance on Unconventional Gassy Well Application thru Modern VFD Technology

High volume, high water cut wells historically represent a challenge in terms of economic production, due to limitations with others artificial lift methods, ESPs are usually chosen for this type of application since it can move great volumes of fluid produced by longer laterals being drilled today. As electrical rates increase exponentially, and notably power grid limitations are becoming more common every day, permanent magnet motor technology can combat these issues with high efficiency, however, most of these unconventional applications experience a significant rapid declination on total fluid rate and an exaggerated increase on gas production, which historically has been a limitation for ESP to operate in gassy conditions efficiently. This paper presents the comparative results of an PMM performance using Vector Control Mode vs Scalar Control to demonstrate PMMs performs successfully in gassy applications, riding thru sudden load changes caused by gas slugs on unconventional wells utilizing vector control method that ensures synchronization of the rotor and constant rotor magnetic field. An ESP System was setup using PMM to test on different drives with different control modes, SUT, SWF, ESP Cable, Dyno and Power analyzer were included, both units were exposed to sudden load changes to mimic gas interference, as well as drastic speed changes to simulate purging operating modes used in the field to ride thru gas slug events. Analyzing the results it was noticed that Scalar (V/Hz) mode, which is generally easier to use caused motor system to experience current torque mismatch, showing speed control issue regardless of the load, which indicates poor control, while under vector control mode which is the preferred mode to drive PMMs to ensure rotor synchronization, it chased the load successfully using modern VFD Technology to ride thru large load variations due to high gas interference simulation, confirming output torque matched desired current regardless of sudden speed changes, decoupling speed from torque control without any special requirement other than known motor parameter based on motor design, like Ld, Lq and back EMF. ESP Systems using Permanent Magnet motor demands special control algorithms for an effective control of the motor like Vector control which is the best option since it can control unstable loads, but it requires good information on electrical parameters.