Analysis of Drillstring Dynamics Using an Angular Rate Sensor

• US 20130092439A1
• Filed: 10/12/2012
• Published: 04/18/2013
• Est. Priority Date: 10/14/2011
• Status: Active Grant

• Current Assignee: Weatherford Technology Holdings, LLC (Weatherford International PLC)
• Original Assignee: Precision Energy Services Incorporated (Weatherford International PLC)
• Inventors: Mauldin, Charles Lee, Bartel, Roger P., Berns, Richard
• Granted Patent: US 10,480,304 B2
• Time in Patent Office: Days
• US Class Current: 175/40
• CPC Class Codes: E21B 44/00 Automatic control systems specially adapted for drilling operations, i.e. self-operating systems which function to carry out or modify a drilling operation without intervention of a human operator, e.g. computer-controlled drilling systems; Systems specially adapted for monitoring a plurality of drilling variables or conditions
• CPC Class Codes: E21B 44/005 Below-ground automatic control systems

Abstract

Downhole drilling vibration analysis uses an angular rate sensor on a drilling assembly. During drilling operations, the sensor measures the angular rate of the drilling assembly. Processing circuitry is operatively coupled to the angular rate sensor and is configured to determine whether torsional type vibrations are occurring during drilling based on the angular rate data. Drilling operations can then be modified to overcome or mitigate the torsional type vibrations.

Claims

1. A downhole drilling vibration analysis method, comprising:

drilling with a drilling assembly having at least one angular rate sensor;

measuring angular rate data of the drilling assembly with the at least one angular rate sensor while drilling downhole;

analyzing the measured angular rate data; and

determining that torsional vibration is occurring during drilling based on the analysis.

2. The method of claim 1, wherein measuring the angular rate data of the drilling assembly with the at least one angular rate sensor while drilling downhole comprises measuring the angular rate with an angular rate gyroscope responsive to Coriolis acceleration.

3. The method of claim 1, wherein analyzing the measured angular rate data comprises determining a pattern of vibration per one or more revolutions of the drilling assembly from the measured angular rate data.

4. The method of claim 3, wherein determining that torsional vibration is occurring during drilling based on the analysis comprises determining a severity measure of the torsional vibration based on one or more aspects of the determined pattern.

5. The method of claim 1, wherein analyzing the measured angular rate data comprises determining one or more cycles of increased angular rate of the measured angular rate data per one or more revolutions of the drilling assembly.

6. The method of claim 5, wherein determining that torsional vibration is occurring during drilling based on the analysis comprises calculating a torsional vibration measure, indicative of the torsional vibration, based on a number of the one or more cycles.

7. The method of claim 5, wherein determining that torsional vibration is occurring during drilling based on the analysis comprises calculating a torsional vibration measure, indicative of the torsional vibration, based on an amplitude of the one or more cycles.

8. The method of claim 1, wherein analyzing the measured angular rate data comprises determining vibration over revolutions over time of the drilling assembly.

9. The method of claim 8, wherein determining that torsional vibration is occurring during drilling based on the analysis comprises calculating a torsional vibration measure, indicative of the torsional vibration, based on a frequency of the vibration over the revolutions over time of the drilling assembly.

10. The method of claim 1, wherein analyzing the measured angular rate data comprises determining maximum revolutions over time, minimum revolutions over time, and average revolutions over time.

11. The method of claim 10, wherein determining that torsional vibration is occurring during drilling based on the analysis comprises calculating a dimensionless measure relating the maximum revolutions over time, the minimum revolutions over time, and the average revolutions over time.

12. The method of claim 1, wherein the at least one angular rate sensor comprises at least two angular rate sensors displaced along the drilling assembly.

13. The method of claim 12, wherein measuring the angular rate data comprises measuring the angular rate data about a same axis with the at least two angular rate sensors downhole while drilling with the drilling assembly.

14. The method of claim 12, wherein analyzing the measured angular rate data comprises comparing the angular rate data from the at least two angular rate sensors.

15. The method of claim 14, wherein determining that torsional vibration is occurring during drilling based on the analysis comprises determining an aspect of at least one of bending or twisting of the drilling assembly based on the comparison.

16. The method of claim 1, further comprising changing one or more operating parameters of the drilling assembly based on the determined torsional vibration.

17. The method of claim 16, wherein changing the one or more operating parameters of the drilling assembly comprises changing one or more of weight on bit, rotational speed, torque, pump rate, mud flow rate, and mud motor operation.

18. The method of claim 16, wherein changing the one or more operating parameters comprises operating a drilling interrupting mechanism on the drilling assembly based on the determined torsional vibration.

19. The method of claim 1, wherein analyzing and determining comprises at least partially processing the measured angular rate data downhole at the drilling assembly.

20. The method of claim 19, wherein analyzing and determining comprises communicating the at least partially processed angular rate data from the drilling assembly to the surface.

21. The method of claim 20, wherein analyzing and determining comprises completing processing of the measured angular rate data downhole at the surface.

22. A downhole drilling vibration analysis method, comprising:

drilling with a drilling assembly having an angular rate sensor;

measuring instantaneous rotational speed relative to revolutions of the drilling assembly with the angular rate sensor while drilling downhole;

analyzing the measured instantaneous rotational speed relative to the revolutions; and

determining that torsional vibration is occurring during drilling based on the analysis.

23. A drilling assembly, comprising:

a drill collar disposed on a drill string;

a drill bit disposed on the drill collar;

at least one angular rate sensor disposed on the drill collar and measuring angular rate data downhole while drilling with the drilling assembly; and

processing circuitry in communication with the at least one angular rage sensor, the processing circuitry analyzing the measured angular rate data and determining that torsional vibration is occurring during drilling based on the analysis.

24. The assembly of claim 23, wherein the at least one angular rate sensor comprises an angular rate gyroscope responsive to Coriolis acceleration.

25. The assembly of claim 23, wherein the processing circuitry comprises first circuitry disposed on the drill collar.

26. The assembly of claim 23, wherein the processing circuitry comprises second circuitry disposed at the surface.

27. The assembly of claim 23, further comprising telemetry unit communicating information indicative of the torsional vibration from the drill collar to the surface.

28. The assembly of claim 23, further comprising a mechanism disposed on the drilling assembly and operable to interrupt drilling by the drill bit.