When Conventional ESP Meets the Unconventional Limit: Putting More Power Downhole Safely

Permanent magnet motors (PMM) have been around for two decades in the electrical submersible pumps (ESP) industry. PMM are shorter-lighter-higher power density in design and offer more than just energy savings with reduced carbon footprint; it is a technology enabler to achieve asset optimization and yet is underutilized. This paper discusses the early reporting on the first company organic PMM safely installed in a Permian Basin unconventional resource well to extract more reservoir production. The benefit to the reader is stronger confidence to apply this green technology in their wells safely and economically. To achieve sustainable first use of PMM, the ESP design and safety implications required collaboration of disciplines involving teams of Instrumentation & Electrical, Production and Completion engineers, the ESP Center of Excellence, the Technical Center, Health-Safety-Environmental, and a variety of vendors over a 2-year period. Pump design and drawdown scenarios were examined while multiple safety trainings were conducted, including live demonstrations with PPE, proving the safe mitigation of hazardous voltage through proper shunting, grounding, and isolating standard operating procedures. Additionally, multiple safety devices were added (surface and subsurface) to manage the safety aspects of this technology. A final risk assessment was conducted and approved to clear the way for PMM installation. Compared to the conventional induction motor, the PMM enabled nearly 50% more power downhole for equal fluid density, comparable production and water cut without a change in pump design. Energy savings and carbon footprint reduction is 19%. Since installation, the ESP system has reduced head pressure more than 300 psi and continues to see increased production. Standard operating procedures for PMM were executed successfully and safely without incident using the free hub second source power mitigator. Four electrical technologies are included in this paper for safety of personnel and the asset as PMM bring the risk of electrical shock due to two sources of power: planned power from the grid and unplanned power from the well; the latter case the PMM is a generator and this risk is mitigated with the use of both completion and production tools such as the free hub. Additionally, the non-intrusive power measurement technology at the surface keeps personnel safe from arc-flash and electrical shock without the use of cumbersome CAT-2 PPE, a health risk in hot climates. A contactor switch at the surface helps to protect life and asset. Lastly, a common mode filter was run for carrier frequencies less than 4000 Hz to reduce or eliminate high frequency induced failures such as bearing fluting.