As independent world leaders in artificial lift monitoring systems, Zenith has the knowledge and experience to continually develop technologies that meet the challenges faced by the industry. 

Dave Shanks, Development Manager - Zenith Special Technology Group , introduces our latest development in ESP monitoring set to eliminate a prevalent, persistent problem…

Ground Fault Immune ESP Gauge

Q. What experience do you have in the industry that led you to realise the need for this new technology and positioned your team to develop it?

A. Operators have been using DC current based technology for over 40 years and have consistently had a percentage of these sensors fail because of earth leakage in the ESP cable, so it does not take long talking to customers to identify this problem. Finding an alternative to DC sensors has been a real challenge for the entire industry and up to now one that has never been solved. I built my first attempt at a fault tolerant ESP gauge in 1995 so have been trying to solve this challenge for some time! The Zenith Special Technology Group made some real breakthroughs about two years ago which allowed us to make a fault immune system a reality.

Q. How does the Ground Fault Immune gauge technology address the industry problem?

A. The Ground Fault Immune gauge will run normally with any single phase shorted to ground and any two phases with partial faults to ground — effectively the operator will continue to receive reliable downhole data as long as the ESP cable is operational, making the system considerably more robust than existing technology. In basic terms, if the ESP is running the gauge will be working, removing the ground fault problem from the industry once and for all.

Q. Compared to currently available technologies, how will operators benefit from this development?

A. The ability to maintain continuous monitoring on all operational ESP systems has to be the goal of any operator, and this tool will do just that. Having the ability to measure the location and severity of the cable fault enables more informed decisions to be made regarding problematic pumping systems. In addition, the technology ensures that reservoir build ups are caught when the pump shuts down, and at higher logging rates than previously possible.

Q. What were the challenges, milestones and lessons learned in this tech’s development?

A. Running a downhole gauge in cable fault conditions means it has to operate normally with the full motor voltage across it, so making a tool that is just as happy running with 50 volts power as 5,000 volts was a real challenge. We also had to make sure that noise from variable speed drives would not cause problems with the data transmission and this became one of our greatest problems — and achievements — in getting the tool fully operational.We now have three granted patents and a fourth pending relating to the technology in the Ground Fault Immune gauge so this has been a major piece of work in every respect.

Q. What’s the future for Zenith’s Ground Fault Immune technology?

A. The immediate future is to ensure field-proven reliability. We are initially deploying the technology as an add-on to the already industry-proven Zenith E-Series monitoring system. Given good results the Ground Fault Immune technology can run independently, allowing us to produce much smaller and even more robust tools. This technology is beginning to open up many new avenues for measurement below an ESP; Zenith plan to introduce a range of tools based around this technology which will utilise the high speed data transmission and reasonable available power downhole for other instrumentation, including a flow meter — watch this space!