High spatial resolution fiber optic temperature sensor

• US 8,630,816 B2
• Filed: 11/16/2009
• Issued: 01/14/2014
• Est. Priority Date: 11/17/2008
• Status: Active Grant

• Current Assignee: Sensortran Incorporated (Halliburton Company)
• Original Assignee: Sensortran Incorporated (Halliburton Company)
• Inventors: Park, Brian, Fassih-Nia, Mohammed, McCoy, Brian K., Kalar, Kent, Jaaskelainen, Kari-Mikko
• Primary Examiner(s): Lau, Tung S
• Assistant Examiner(s): Chang, Stephanie
• Application Number:
  US12/998,626
• Publication Number:
  US 20120010846A1
• Time in Patent Office: 1,520 Days
• Field of Search: 702/134
• US Class Current: 702/134
• CPC Class Codes: G01F 23/22 by measuring physical variables, other than linear dimensions, pressure or weight, dependent on the level to be measured, e.g. by difference of heat transfer of steam or water involving the use of floats G01F23/30
• CPC Class Codes: G01F 23/292 Light , e.g. infrared or ultraviolet
• CPC Class Codes: G01K 11/32 using changes in transmittance, scattering or luminescence in optical fibres

Abstract

High resolution distributed temperature sensors using fiber optic distributed temperature sensing systems deployed on various carriers to significantly improve spatial resolution and provide high resolution temperature profile and detection of fluid or fluid interface levels.

Claims

1. A high resolution distributed temperature sensor (DTS) assembly comprising:

a. a processor;

b. a DTS system coupled to the processor; and

c. a sensor coupled to the DTS system, the sensor comprising;

i. a sensor carrier;

ii. a covering material disposed around said sensor carrier;

iii. a first optical fiber having a first end and a second end wrapped along a portion of the carrier and over said covering material at one or more predetermined pitchs;

iv. an optical connector for joining two optical fibers connected at said second end of said first optical fiber; and

v. a second optical fiber for communicating the sensed parameters to the DTS system;

said second optical fiber connected to said first optical fiber using said optical connector.

2. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said second optical fiber is deployed back to and is coupled to said DTS system.

3. The high resolution distributed temperature sensor (DTS) assembly of claim 2 wherein said first optical fiber is also deployed back to and is coupled to said DTS system.

4. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein the combination of carrier circumference and pitch give a resolution of less than 100 millimeters.

5. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein the combination of carrier circumference and pitch give a resolution of less than 25 millimeters.

6. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein the combination of carrier circumference and pitch give a resolution of less than 10 millimeters.

7. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said the shape of said sensor carrier is cylindrical.

8. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said the shape of said sensor carrier is selected from the group consisting of elliptical, spherical, hemispherical, toroidal, cubic, pyramidal, and rectangular.

9. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said sensor carrier is flexible.

10. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said covering material is a heat shrink material.

11. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said covering material is a flexible potting compound.

12. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said pre-determined pitch of said first optical fiber is uniform along the dimension of said sensor carrier.

13. The high resolution distributed temperature sensor (DTS) assembly of claim 1 wherein said pre-determined pitch of said first optical fiber is variably deployed along the dimension of said sensor carrier to vary the resolution of measurement.

14. The high resolution distributed temperature sensor (DTS) assembly of claim 1 further comprising added weights to said sensor carrier.

15. The high resolution distributed temperature sensor (DTS) assembly of claim 1 further comprising an internal electric heating cable deployed in said sensor carrier to enable periodic heating of said sensor.

16. The high resolution distributed temperature sensor (DTS) assembly of claim 15 wherein said sensor is deployed into tanks or deep wells and said periodic heating of said sensor and the DTS measurement of temperature profile is used for fluid level determination in said tanks or deep wells.

17. The high resolution distributed temperature sensor (DTS) assembly of claim 1 further comprising the use of heated fluids in said sensor carrier to enable periodic heating of said sensor.