Fiber optic vibration monitoring

Patent metadata

Field	Value
Publication number	US-9739142-B2
Application number	US-201414459475-A
Country	US
Kind code	B2
Filing date	Aug 14, 2014
Priority date	Sep 16, 2013
Publication date	Aug 22, 2017
Grant date	Aug 22, 2017

Abstract

An apparatus for monitoring vibration of a downhole component includes an optical fiber sensor including at least one optical fiber operably connected to an interrogation unit. The at least one optical fiber has a resonant segment that is fixedly attached to the component via attachment points on the component, the resonant segment between the attachment points being separate from the component and having a resonant frequency based at least on the length of the resonant segment.

First claim

What is claimed is:

1. An apparatus for monitoring vibration of a downhole component, the apparatus comprising:
an optical fiber sensor including at least one optical fiber operably connected to an interrogation unit, the at least one optical fiber having a resonant segment, the resonant segment fixedly attached to the component via attachment points on the component, the resonant segment between the attachment points being separate from the component and having a selected resonant frequency, the resonant segment having a length defined by the attachment points, the length configured to cause the resonant segment to have the selected resonant frequency.

2. The apparatus of claim 1 , wherein the resonant segment is held in tension between the attachment points.

3. The apparatus of claim 1 , wherein the attachment points are configured to rigidly attach ends of the resonant segment to the component selected resonant frequency is a frequency of at least one of mechanical vibration and fluid vibration.

4. The apparatus of claim 1 , wherein the resonant segment between the attachment points is not in contact with the component and is allowed to vibrate freely.

5. The apparatus of claim 1 , wherein the resonant segment is disposed within a cavity attached to the component.

6. The apparatus of claim 5 , wherein the cavity is filled with a filler material configured to alter the resonant frequency.

7. The apparatus of claim 6 , wherein the filler material is a multiphase fluid.

8. The apparatus of claim 1 , wherein the resonant frequency is selected based on an expected vibrational frequency of the component.

9. The apparatus of claim 1 , wherein at least a portion of the optical fiber sensor is disposed within a tubular that is rigidly attached to the component, and the attachment points are rigid structures extending from an interior surface of the tubular.

10. The apparatus of claim 1 , wherein the resonant segment follows a spiral path around the component.

11. A method of monitoring a downhole component, the method comprising:
disposing a component at a downhole location;
disposing an optical fiber sensor connected to the component at the downhole location, the optical fiber sensor including at least one optical fiber having a resonant segment, the resonant segment fixedly attached to the component via attachment points on the component, the resonant segment between the attachment points being separate from the component and having a selected resonant frequency, the resonant segment having a length defined by the attachment points, the length configured to cause the resonant segment to have the selected resonant frequency;
transmitting an electromagnetic interrogation signal into the optical fiber sensor via an interrogation unit, and receiving reflected signals from sensing locations in the resonant segment of the optical fiber sensor; and
estimating a vibration of the component based on the reflected signals.

12. The method of claim 11 , wherein the resonant segment is held in tension between the attachment points.

13. The method of claim 11 , wherein the attachment points are configured to rigidly attach ends of the resonant segment to the component.

14. The method of claim 11 , wherein the resonant segment between the attachment points is not in contact with the component and is allowed to vibrate freely.

15. The method of claim 11 , wherein the resonant segment is disposed within a cavity attached to the component.

16. The method of claim 15 , wherein the cavity is filled with a filler material configured to alter the resonant frequency.

17. The method of claim 16 , wherein the filler material is a multiphase fluid.

18. The method of claim 11 , wherein the resonant frequency is selected based on an expected vibrational frequency of the component.

19. The method of claim 11 , wherein at least a portion of the optical fiber sensor is disposed within a tubular that is rigidly attached to the component, and the attachment points are rigid structures extending from an interior surface of the tubular.

20. The method of claim 11 , wherein the resonant segment follows a spiral path around the component.

Assignees

• Cooper Daniel Boyd
• Lee Erik N
• Baker Hughes Inc

Inventors

• Cooper Daniel Boyd
• Lee Erik N

Classifications

• G01S15/88

  Sonar systems specially adapted for specific applications (seismic or acoustic prospecting or detecting G01V1/00) · CPC title

• E21B47/008 Primary

  Monitoring of down-hole pump systems, e.g. for the detection of "pumped-off" conditions · CPC title

• E21B47/135 Primary

  using light waves, e.g. infrared or ultraviolet waves · CPC title

• E21B47/00

  Survey of boreholes or wells (monitoring pressure or flow of drilling fluid E21B21/08) · CPC title

• E21B47/123 Primary

  Fixed Constructions · mapped topic