A New Technology in Real Time Downhole Vibration, Pressure, and Temperature Measurement for Artificial Lift Systems
Our Breakthrough In Downhole Telemetry
Our R&D engineering group at GEO PSI has developed a new robust downhole telemetry for our permanent downhole tools that greatly improves the speed, quantity, and quality of downhole data transmission. Similar to most other advanced permanent downhole gauges, GEO PSI’s transmits updated Pressure and Temperature readings once per second.
The breakthrough development is that the GEO PSI tool sends a new comprehensive snapshot of the horizontal and vertical acceleration waveforms to surface every 20 seconds. Additionally, the GEO PSI tool is capable of sampling at multiple frequencies to suit the pump type. With this waveform, your gauge can determine not only peak vibration as other tools do, but downhole pump cards, velocity profiles, displacement, failure analysis, harmonics, and more.
The data will be invaluable for advanced downhole pump optimization and diagnostics for ESP, PCP, and Rod Pump systems. Such understanding will provide pump companies and end users correlational data for better artificial lift decision performance.
The Limitation Of Resonant Vibration Data
Several manufacturers offer permanent downhole sensors that measure pressure, temperature, and resonant vibration data. Resonant vibration data is a record of the most extreme horizontal and vertical g-force data recorded between sample intervals. This data alone, however, does not form a complete picture of pump performance, therefore limiting the amount of meaningful insight that can be provided to the customer.
A good analogy is the human tolerance of g-forces. Certainly one can relate to roller coaster enthusiasts and military jet pilots. We know that military pilots can die from constant vertical g-force exertions of 6 g’s for a period of 60 seconds or less, whereas the most extreme roller coaster in the world pulls 4.5 g’s, but has never killed anyone. However, if the roller coaster suddenly changed directions 10 times per second and caused the riders bodies to quickly be pulled by both negative and positive g’s, the ride would not be survivable.
Downhole pumps are really not much different. To truly understand downhole pump performance we really need to isolate the frequency and amplitude of the g-forces, not just the resonant values.
Until now, sensor manufacturers have only been able to transmit data to the surface about 1 sample per second. Vibration data has been limited to resonant g-force value. GEO PSI is set to change that.
Vibration Data Recorded at 10 Hz
Overview of Graphical Representations
- Plot 1 – Raw Data Format. This simply represents the vertical and horizontal acceleration vs. time. Note that the vertical acceleration records the effect of gravity at 1g combined with the vibration signal.
- Plot 2 – Fast Fourier Computation. A plot of the peak to peak amplitude at each frequency.
- Plot 3 – The same data from Plot 2, but converted to a db. log scale, which may be easier to interpret. It is more sensitive to the weaker signal components. We imagine this may be useful for high-frequency analysis such as bearing failure or certain stator wear.
- Plot 4 – Velocity vs. Frequency Plot. The velocity computed from the acceleration data. The velocity failure is the most useful data for pump condition analysis.
- Plot 5 – Displacement. It is derived from the velocity data and is primarily used for low-frequency analysis and is related to metal fatigue.