Fluorescence spectroscopy for estimation of fluid contamination

Patent metadata

Field	Value
Publication number	US-12276609-B2
Application number	US-202217888578-A
Country	US
Kind code	B2
Filing date	Aug 16, 2022
Priority date	Aug 16, 2022
Publication date	Apr 15, 2025
Grant date	Apr 15, 2025

Abstract

A method of analyzing a fluid includes acquiring a sample of the fluid extracted from a subterranean region proximate to a borehole, the borehole including an injected fluid, applying light having a first excitation wavelength to the fluid sample, and measuring a first fluorescence spectrum. The method also includes comparing the first fluorescence spectrum to a reference fluorescence spectrum corresponding to a fluid having injected fluid contamination and/or to a second fluorescence spectrum based on applying light having a second excitation wavelength to the fluid sample. The method further includes estimating a level of contamination of the fluid sample with the injected fluid based on the comparing.

First claim

What is claimed:

1. A method of analyzing a fluid, comprising:
acquiring a sample of the fluid extracted from a subterranean region proximate to a borehole, the borehole including an injected fluid;
applying light having a first excitation wavelength to the fluid sample, and measuring a first fluorescence spectrum;
comparing the first fluorescence spectrum to at least one of: a reference fluorescence spectrum corresponding to a fluid having injected fluid contamination, and a second fluorescence spectrum based on applying light having a second excitation wavelength to the fluid sample; and
estimating a level of contamination of the fluid sample with the injected fluid based on the comparing, wherein comparing the first fluorescence spectrum to the reference fluorescence spectrum includes identifying a first peak in the first fluorescence spectrum, identifying a second peak in the reference fluorescence spectrum, and estimating a wavelength shift between the first peak and the second peak.

2. The method of claim 1 , wherein the level of contamination corresponds to at least one of a proportion, percentage and concentration of the injected fluid in the fluid sample.

3. The method of claim 1 , wherein the fluid sample is acquired by sampling the fluid from a borehole, and the estimating is performed when the fluid sample is downhole.

4. The method of claim 1 , wherein the fluid sample is acquired and the level of contamination is estimated in real time during a subterranean operation.

5. The method of claim 1 , wherein the level of contamination is estimated based on a magnitude of the wavelength shift.

6. The method of claim 1 , wherein comparing the first fluorescence spectrum to the second fluorescence spectrum includes identifying a first peak and a second peak of the first fluorescence spectrum, and estimating a first ratio of an intensity of the first peak to an intensity of the second peak.

7. The method of claim 6 , wherein comparing the first fluorescence spectrum to the second fluorescence spectrum includes identifying a third peak and a fourth peak of the second fluorescence spectrum, and estimating a second ratio of an intensity of the third peak to an intensity of the fourth peak.

8. The method of claim 7 , wherein comparing the first fluorescence spectrum to the second fluorescence spectrum includes calculating a difference between the first ratio and the second ratio.

9. The method of claim 8 , wherein the amount of contamination is estimated based on the difference.

10. A system for analyzing a fluid, comprising:
a sampling device disposed at a borehole string and configured to extract a sample of the fluid from a subterranean region proximate to a borehole;
a spectroscopy device disposed at the borehole string and configured to receive the sample, the spectroscopy device including a fluorescence spectroscopy unit configured to apply light having a first excitation wavelength to the fluid sample, and a processor configured to perform:
measuring a first fluorescence spectrum indicative of a spectral response of the fluid sample to the first wavelength;
comparing the first fluorescence spectrum to at least one of: a reference fluorescence spectrum corresponding to a fluid having injected fluid contamination, and a second fluorescence spectrum based on applying light having a second excitation wavelength to the fluid sample by the spectroscopy device; and
estimating a level of contamination of the fluid sample with the injected fluid based on the comparing, wherein comparing the first fluorescence spectrum to the reference fluorescence spectrum includes identifying a first peak in the first fluorescence spectrum, identifying a second peak in the reference fluorescence spectrum, and estimating a wavelength shift between the first peak and the second peak.

11. The system of claim 10 , wherein the level of contamination corresponds to at least one of a proportion, percentage and concentration of the injected fluid in the fluid sample.

12. The system of claim 10 , wherein the estimating is performed when the fluid sample is downhole.

13. The system of claim 10 , wherein the fluid sample is acquired and the level of contamination is estimated in real time during a subterranean operation.

14. The system of claim 10 , wherein the level of contamination is estimated based on a magnitude of the wavelength shift.

15. The system of claim 10 , wherein comparing the first fluorescence spectrum to the second fluorescence spectrum includes identifying a first peak and a second peak of the first fluorescence spectrum, and estimating a first ratio of an intensity of the first peak to an intensity of the second peak.

16. The system of claim 15 , wherein comparing the first fluorescence spectrum to the second fluorescence spectrum includes identifying a third peak and a fourth peak of the second fluorescence spectrum, and estimating a second ratio of an intensity of the third peak to an intensity of the fourth peak.

17. The system of claim 16 , wherein comparing the first fluorescence spectrum to the second fluorescence spectrum includes calculating a difference between the first ratio and the second ratio.

18. The system of claim 17 , wherein the amount of contamination is estimated based on the difference.

Assignees

• Maity Sandip
• Cartellieri Ansgar
• Baker Hughes Oilfield Operations Llc

Inventors

• Maity Sandip
• Cartellieri Ansgar

Classifications

• G01N2021/6421

  Measuring at two or more wavelengths · CPC title

• G01N2021/6419

  Excitation at two or more wavelengths · CPC title

• G01N2001/1418

  Depression, aspiration · CPC title

• G01N21/64 Primary

  Fluorescence; Phosphorescence · CPC title

• E21B49/08 Primary

  Obtaining fluid samples or testing fluids, in boreholes or wells · CPC title