Dynamometers Cards Benefits of High Speed and High Resolution Data Acquisition

1. Beam Pumping Workshop Houston, Texas October 4 - 7, 2005 Dynamometers Cards Benefits of High Speed and High Resolution Data Acquisition Lynn Rowlan

2. PORTABLE WELL ANALYZER w/ SENSORS

3. Typical Rod Pump Control System

4. High Speed Data Acquisition • Data can be acquired at time intervals of 15, 30, 60, 120, 240, 480, or greater samples per second. • A high speed laptop computer allows data to be recorded at the optimum resolution of state-of-the-art instrument using sigma-delta analog to digital converters, precision sensors, and shielded cables.

5. Older Style Analog to Digital ConvertersDO NOT Have Sensitivity for Small Signals C111 C112 - 3584 Ft Deep 0.2 PSI For 30K Load Cell 8 bit - 58 lb/step 12 bit – 7 lb/step 24 bit – 0.002 lb/step Acoustic Signal Show Plunger Fall Past 111th and 112th Tubing Collar Zoom in on Axis From 40.554 to 0.3 mins

6. Record Surface & Calc. Pump Cards • Surface Dynamometer cards is the plot of measured polished rod load at the various positions throughout a complete stroke • Used for for designing and diagnosing surface problems. • Pump dynamometer card is a plot of the calculated loads at various positions of pump stroke and represents the load the pump applies to the bottom of the rod string. • Used for analysis of downhole problems. Surface Card Pump Card

7. Acquire Load & Acceleration Versus Time Identify individual strokes and process acceleration data to get velocity and position Analyze Stroke #1

8. One Stroke of Polished Rod Acceleration Integrated to Determine Polished Rod Velocity Top Bottom Bottom

9. Polished Rod Velocity Integrated to Determine Polished Rod Position Top Bottom Bottom

10. Acceleration Load Integrate once Surface Card Integrate again Wave Down To Pump Pump Card

11. Downward Spike on Pump Card Near Bottom, Appears to be Improperly Spaced POC Data Bottom Top

12. String Boxes and Inclinometers Error in Position Data from Inclinometer • Tends to have poor resolution at top and bottom of stroke • Smoothing of the Position data required to prevent load spikes

13. Noise in Position Data Requires Filtering of Acquired Signal POC Data

14. Spikes on Pump Card Near CenterCaused by Noise in Position Data POC Data

15. Averaging Important for Longer Duration Event 10 Second • Blue - 20 Samples per Second results in 20 data values acquired during event. • Black – Median Filter without Regression • Averaging Smoothes out Peaks and Flattens Curve

16. A 5 Order Best Fit Regression FilterSmoothed Out Noise in Pump Card POC Data

17. Sampling Rate Important for 1/10 Sec Duration High Speed Event 1 Second • Blue - 20 Samples per Second results in 2 data values acquired during event. • Black - 240 Samples per Second results in 24 data values acquired during event • Sampling to slow can completely miss occurrence an Event

18. Shock Loads Increased Rod Failures:Gunk in Pump Two TVs in Pump 10 Klb 6.5 Klb

19. In 0.1 Second 10,000 Lbs Impacts Rods on Upstroke 0.6 Seconds Surface Velocity Slows by 6 in/sec Two TVs in Pump Zero Velocity

20. High Speed Sampling Shows Correct Tag Force TAG 6500 Lb TAG 30 Samples/Second 240 Samples/Second

21. Compare Tag Force of 30 & 240 Hz 30 Samples/Second 6500 Lb TAG 240 Samples/Second

22. Stress waves due to “tagging” + Zero Velocity -

23. Noisy or poor quality data requires special processing/smoothing to prevent false load spikes. High speed/high resolution data required to see character of sudden impact loads. High speed/high resolution data is used to clearly analyze the severity of sudden impact loads. High Speed and High Resolution Data Acquisition

24. Questions ?