Cost-Effective and Environmentally Sustainable Permanent Magnet Motor for Artificial Lift

Abstract

Abstract The challenge of climate change and the imperative of moving to a low carbon economy has intensified and added to traditional objectives of affordable, safe, and clean energy in oil and gas production. Recycling parts from artificial lift equipment has been an industry-standard practice for decades. Equipment component reclaim has been a way to deliver high-quality, cost-effective products to our customers, especially in tough market times. It will be a critical best practice to reduce carbon emissions and enhance environmental sustainability. With customer cooperation, service companies develop procedures to re-use the most significant components of an Electrical Submersible Pump (ESP) system. These include the pump, cable, seal chamber section, and motor. The motor stator, bearings, and rotors are a high percentage of reclaimable parts in an ESP system. Reclaiming the induction motor (IM) rotors has been standard practice for decades. However, with the advent of permanent magnet motors (PMM) and the change in rotor construction, the current process does not apply. The driving force for PMM application is to improve energy efficiency and lower cradle to grave carbon emissions. We could not fully realize the vision of environmental sustainability and reduced carbon footprint if PMM rotors were not part of the reclaim process. Therefore, recycling the PMM rotors strengthens the justification for replacing IMs with PMMs, especially given that the value of magnetic material is highly variable and has doubled in the past year. The PMM rotors from a recovered motor may suffer from de-magnetization or be contaminated with production fluids or metal debris. Like IM rotors, the most effective method to remove contaminants from the PM rotor is to bake at high temperatures for a period. However, baking the PMM rotor magnets at elevated temperatures will be at least partially de-magnetized during the process and result in the PMM rotors no longer meeting performance specifications. This paper will present innovative technology and apparatus to re-magnetize the de-magnetized rotors for reclaiming. The research has developed a process where, without disassembling the rotor, the magnets in the rotor are re-magnetized in-situ by a specific apparatus. Testing has proven that PMMs assembled with reclaimed rotors have the same performance-rated power and torque as those built with new rotors. On the other hand, since magnets in PMMs account for more than 50% of total carbon emission of all reclaimable parts in PMMs, factoring in mining, manufacturing, logistics, and processing of magnets that generates toxic by-products to the environment, PMM rotor recycling contributes to corporate responsibility and our overall ESG (Environmental, Social, and Governance) rating. Furthermore, reclaiming PMM rotors can enable us to build PMM more cost-effectively, gain competitiveness in the market, and keep our PMM supply chain more stabilized.