Measurement of scale inhibitor in water systems

Patent metadata

Field	Value
Publication number	US-2016349186-A1
Application number	US-201615167990-A
Country	US
Kind code	A1
Filing date	May 27, 2016
Priority date	May 28, 2015
Publication date	Dec 1, 2016
Grant date	—

Abstract

A method for determining a concentration of a scale inhibitor in a water system comprises: 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

1 . A method for determining a concentration of a scale inhibitor in a water system, the method comprising:
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.

2 . The method of claim 1 , further comprising separating the scale inhibitor from an inorganic salt contained in a sample of the water system 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 a sample of the water system comprises less than about 15 wt % of sodium chloride, sodium acetate, and sodium sulfate, or a combination thereof, based on the total weight of the sample.

6 . The method of claim 1 , further comprises diluting a sample of the water system so that the concentration of sodium chloride, sodium acetate, and sodium sulfate, or a combination thereof is less than 15 wt. %, based on the total weight of the sample.

7 . The method of claim 1 , wherein the water system 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 a 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

• G01N21/78 Primary

  producing a change of colour · CPC title

• G01N2021/7786

  Fluorescence · 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

• G01N33/1833

  Oil in water · CPC title

• C02F2209/003

  Downstream control, i.e. outlet monitoring, e.g. to check the treating agents, such as halogens or ozone, leaving the process · CPC title