Measurement of scale inhibitor in water systems

Patent metadata

Field	Value
Publication number	US-9612204-B2
Application number	US-201615167990-A
Country	US
Kind code	B2
Filing date	May 27, 2016
Priority date	May 28, 2015
Publication date	Apr 4, 2017
Grant date	Apr 4, 2017

Abstract

A method for determining a concentration of a scale inhibitor in a water system that includes contacting a scale inhibitor with a dye in a capillary channel to form a complex effective to generate fluorescence; measuring a fluorescence signal generated by the complex; and, determining the concentration of the scale inhibitor based on the fluorescence signal.

First claim

The invention claimed is:

1. A method for determining a concentration of a scale inhibitor in a water system, the method comprising:
contacting a sample of water containing scale inhibitor with a dye in a capillary channel to form a complex effective to generate fluorescence;
measuring a fluorescence signal generated by the complex; and
determining a concentration of the scale inhibitor based on the fluorescence signal.

2. The method of claim 1 , further comprising separating the scale inhibitor from an inorganic salt contained in said sample of water in the capillary channel before forming the complex.

3. The method of claim 1 , wherein the scale inhibitor comprises an anionic scale inhibitor.

4. The method of claim 1 , wherein the scale inhibitor comprises a phosphate ester; a phosphonate; a polycarboxylate; a phosphine polymer; a sulfonate; polyvinyl sulfate; or a combination comprising at least one of the foregoing.

5. The method of claim 1 , wherein said sample of water comprises less than about 15 weight percent (wt %) of sodium chloride, sodium acetate, and sodium sulfate, or a combination thereof, wherein said wt % is based on a total weight of said sample of water.

6. The method of claim 1 , further comprising the step of diluting said sample of water so that the concentration of sodium chloride, sodium acetate, and sodium sulfate, or a combination thereof is less than 15 weight percent (wt %) before said measuring step, wherein said wt % is based on a total weight of said sample of water.

7. The method of claim 1 , wherein said water sample is from a water system that is an oilfield fluid comprising seawater, formation water, produced water, a drilling fluid, a completion fluid, a stimulating fluid, a squeezing fluid, or a combination comprising at least one of the foregoing.

8. The method of claim 1 , further comprising filling the capillary channel with an electrolyte, and introducing said water sample comprising the scale inhibitor to the capillary channel filled with the electrolyte.

9. The method of claim 8 , wherein the electrolyte comprises a buffer salt and a polymer.

10. The method of claim 8 , wherein the electrolyte has a pH of about 7 to about 10.

11. The method of claim 8 , wherein the electrolyte further comprises an amino acid.

12. A method for determining a concentration of a scale inhibitor in a water system, the method comprising:
providing a capillary channel having an inlet end and an outlet end, wherein the capillary channel is filled with an electrolyte comprising a buffer salt, a polymer, and a dye;
loading a sample containing a scale inhibitor into the capillary channel from the inlet end;
forming a fluorescent complex of the scale inhibitor and the dye;
measuring a fluorescence signal generated by the complex; and
determining the concentration of the scale inhibitor based on the fluorescence signal.

13. The method of claim 12 , further comprising separating the scale inhibitor from a salt in the sample before forming the complex.

14. A method of treating a water system, the method comprising:
introducing an effective amount of a scale inhibitor to a water system;
obtaining a sample of the water system containing the scale inhibitor;
contacting the scale inhibitor in the sample with a dye in a capillary channel to produce a complex effective to generate fluorescence;
measuring a fluorescence signal generated by the complex;
determining a concentration of the scale inhibitor based on the fluorescence signal; and
adding an additional quantity of a scale inhibitor to the water system if the measured concentration is below a given value.

15. The method of claim 14 , further comprising separating the scale inhibitor from a salt in the sample before forming the complex.

16. The method of claim 14 , wherein the scale inhibitor comprises an anionic scale inhibitor.

Assignees

• Conocophillips Co
• Advanced Analytical Tech Inc

Inventors

• LOCKLEAR Jay Edward
• Baugh Thomas
• Varineau Pierre
• Wei Wei

Classifications

• G01N2021/7786

  Fluorescence · CPC title

• G01N33/2823

  Raw oil, drilling fluid or polyphasic mixtures · CPC title

• G01N21/6428

  Measuring fluorescence of fluorescent products of reactions or of fluorochrome labelled reactive substances, e.g. measuring quenching effects, using measuring "optrodes" (in vivo A61B5/00; immunoassay G01N33/53) · CPC title

• G01N27/44726

  using specific dyes, markers or binding molecules · CPC title

• C02F5/08 Primary

  Treatment of water with complexing chemicals or other solubilising agents for softening, scale prevention or scale removal, e.g. adding sequestering agents · CPC title