Electricity is the lifeblood of the Electric Submersible Pump (ESP), the Variable Frequency Drive (VFD) is the heart that keeps it going, the power cable is the artery that provides the blood and the motor is the equivalent of the body that moves. As Doctors, if we looked at our system "would we pass our annual physical exam"? Surprisingly, there is no specification in our industry for the ‘blood’ or electricity we provide to our ESPs, a shocking (pun intended) omission when most operators desire increased ESP runlife. This paper will identify the key aspects (what and why) of healthy power going downhole and put forward a proposed specification.
In the 2017 ESP Symposium a breakout session was run that looked at downhole power quality (PQ) and posed the question "Is our operating environment worse than other industries and do we apply the best practices from other industries?". The short answer was that our operating environment is extremely challenging and that we have not adopted the learnings that other industries have applied. As part of the breakout, these key learnings were presented. There was overwhelming agreement in the room that a downhole PQ specification is required. Volunteers were solicited to work on a committee to put together such a specification.
This paper will illustrate the best practices from other industries and put forward the rationale and a practical methodology for applying PQ best practices to ESPs. The key aspects of PQ will be presented in layman's terms so that this work can be easily understood by petroleum engineers using ESPs.
Many of the PQ improvements can be implemented retroactively at surface and can provide benefit to existing ESPs as well as provide a basis for technical requirements as part of the surface and downhole specification for new wells. The consequences of poor power quality are ESP component failures (penetrator, cable, splice, MLE / pothead, motor end turn, motor bearing, sensor, shafts) and short runlives. This paper will put the information and practices in the hands of the operator to act to improve ESP runlife.