METHODS AND APPARATUS FOR DUAL SOURCE CALIBRATION FOR DISTRIBUTED TEMPERATURE SYSTEMS

• US 20070223556A1
• Filed: 03/13/2007
• Published: 09/27/2007
• Est. Priority Date: 03/13/2006
• Status: Active Grant

• Current Assignee: Sensortran Incorporated (Halliburton Company)
• Original Assignee: Sensortran Incorporated (Halliburton Company)
• Inventors: Lee, Chung, Sanders, Michael, Kalar, Kent
• Granted Patent: US 7,628,531 B2
• Time in Patent Office: Days
• US Class Current: 374/1
• CPC Class Codes: G01K 11/32 using changes in transmittance, scattering or luminescence in optical fibres
• CPC Class Codes: G01K 15/00 Testing or calibrating of thermometers
• CPC Class Codes: G01N 17/00 Investigating resistance of materials to the weather, to corrosion, or to light
• CPC Class Codes: G01N 21/7703 using reagent-clad optical fibres or optical waveguides using measurement of total internal reflection or attenuated total reflection G01N21/552; optical fibres or waveguides per se G02B

Abstract

Systems and methods for calibrating a temperature sensing system are disclosed. In one respect, a dual light source configuration may be provided. A first light source may illuminate a sensing fiber and an anti-Stokes band may be detected. A second light source may illuminate a sensing fiber and a Stokes band may be detected, where the Stokes band is substantially similar to the anti-Stokes band of the first light source. A ratio between the anti-Stokes and Stokes band may be used to calibrate a temperature sensing system.

Claims

1. A method comprising:

providing a first light source;

providing a second light source, the second light source having a Stokes band substantially similar to an anti-Stokes band of the first light source;

calibrating a temperature sensing system based on the Stokes band and the anti-Stokes band.

2. The method of claim 1, where calibrating comprises selecting a wavelength from the anti-Stokes band and the Stokes band.

3. The method of claim 1, where calibrating comprises determining a difference in anti-Stokes band and the Stokes band.

4. The method of claim 1, where the first light source and second light source are the same light source.

5. The method of claim 1, where the first light source has a wavelength of about 1064 nanometers and the second light source has a wavelength of about 980 nanometers.

6. A method comprising:

providing a first light source and a second light source, the first light source being configured to operate in a measurement mode and the second light source being configured to operate in a correction mode;

illuminating a sensing fiber with the first light source;

detecting an anti-Stokes band using the illumination of the first light source;

illuminating the sensing fiber with the second light source;

detecting a Stokes band using illumination from the illumination of the second light source;

calibrating a temperature sensing system based on a ratio between the Stokes and anti-Stokes band.

7. A system for calibrating a temperature sensing system comprising:

a primary light source for providing an anti-Stokes band;

a secondary light source coupled to the primary light source for providing a Stokes band;

an optical switch for selecting between the primary light source and the secondary light source; and

wherein the system calibrates the temperature sensing system based on a ratio of the anti-Stokes band and Stokes band.

8. The system of claim 7, further comprising a sensing fiber for generating backscattering bands.

9. The system of claim 8, the backscattering bands comprising the anti-Stokes band of the primary light source.

10. The system of claim 8, the backscattering bands comprising the Stokes band of the second light source.