METHOD FOR QUANTITATIVELY MEASURING THE CONCENTRATION OF CHEMICALS IN AQUEOUS SOLUTION

Abstract

The present invention relates to a method for quantitatively measuring concentration in aqueous solution A of chemicals, functionalized with at least one tracer, comprising at least the following successive steps of (a) impregnating a flow assay containing at least one test area, that detects the tracer functionalizing the chemicals to be quantified, with solution A, (b) introducing the flow assay into a test reader, and (c) using the test reader.

Claims

1. Method for quantitatively measuring concentration in aqueous solution A of chemicals, functionalized with at least one tracer, comprising at least the following successive steps: a) Impregnating a flow assay containing at least one test area, that detects the tracer functionalizing the chemicals to be quantified, with solution A, b) Introducing the flow assay into a test reader comprising at least the following elements: a set of control electronics, a signal capturing component, a radiation component, a housing component, a test tray which can hold at least a flow assay having a shape and a fixed position relative to the signal capturing component and the irradiation component, c) Using the test reader by: Optionally exposing the flow assay to radiation to reveal signals of the tracer on the test area, Acquiring a digital image of said signals, Image processing for transforming said signals into test data, Comparing said test data to a calibration curve-determining concentration of the chemicals functionalized by at least one tracer in the aqueous solution.

2. Method according to claim 1 wherein the signal capturing component is a digital image capturing component, the radiation is an electromagnetic radiation and the test data corresponds to measured intensities of pixels of the digital image.

3. Method according to claim 1 wherein the signal capturing component is a magnetic intensity scanning component, the radiation is an alternating magnetic field and the test data is the count of the number of signals.

4. Method according to claim 2 wherein the tracer is a detectable group which can be identified by immunoassay or molecular biological techniques.

5. Method according to claim 2 wherein the tracer is a fluorescent group.

6. Method according to claim 2 wherein the tracer is an organic or inorganic phosphorus group.

7. Method according to claim 3 wherein the tracer is a magnetic particle.

8. Method according to claim 1 wherein the chemical to be traced is a water-soluble polymer.

9. Method according to claim 1 wherein the set of control electronics, the signal capturing component and the component able to produce magnetic radiation are operatively located in a mobile terminal engaged with the housing component.

10. Method according to claim 9 wherein the housing component is a test reader attachment which can be repeatedly attached or detached to a mobile terminal.

11. Method according to claim 2 wherein the signal capturing component is a flash light-emitting diode, that is a part of the digital image capturing component, illuminating the flow assay from the front side.

12. Method to measure quantitatively the concentration of water soluble polymers in back produced water from flooding operation for enhanced oil recovery operation consisting of: injecting an aqueous solution of water soluble polymer functionalized by a tracer in an oil formation through an injection well, performing a flooding operation, collecting fluid in production well, separating oil and back produced water, and measuring the concentration of water soluble polymer in back produced water by the method according to claim 1.

Description

[0069] The following examples are provided to illustrate the present invention. The examples are not intended to limit the scope of the invention.

[0070] FIG. 1 represents representative digital images from the test reader for the calibration curve generation

[0071] FIG. 2 represents the resulting calibration curve.

[0072] FIG. 3 represents a sand pack diagram.

[0073] FIG. 4 represents the effluent concentration profiles, for Species 1 and Species 2, produced from the sand packs during the brine post flush.

EXAMPLES

Example 1: Calibration Curve

[0074] A series of known concentration standards was generated by up to 100,000 serial dilution from a mother solution of 10,000 ppm (active). Lateral Flow Assay (LFA's) were run for each of the 10 calibration standards and the resultant strip(s) was digitally imaged via a test reader. Some representative digital images from the test reader for the calibration curve generation are shown in FIG. 1. The resulting calibration curve is presented in FIG. 2 as a function of concentration.

Example 2: Adsorption Isotherm Sand Pack Preparation

[0075] A surrogate, unconsolidated sand pack was prepared to quantify chemical residuals. A representative sand pack diagram is shown in FIG. 3. Surrogate sand was packed into the column with packing screens on either end. Pore volume was determined using a salinity tracer test.

[0076] Permeability was calculated using Darcy's law,

[00001]$\begin{array}{cc}K=\frac{Q**L}{A*.Math..Math.P}& \left(1\right)\end{array}$

[0077] where K is the permeability in Darcy (D), Q is the flow rate (mL/sec), the viscosity (cPs), L is the length of the sand pack column (cm), A is the area of the sand pack column (cm.sup.2), and P is the pressure (Atm).

Example 3: Dynamic Sand Pack Flood for Residual Chemical Quantification

[0078] The chemical floods were carried out at ambient temperature using a flood sequence resembling a field squeeze process. A typical flood sequence includes: [0079] i) Injection of a spearhead solution [0080] ii) Injection of the chemical tracer concentration at ambient temperature until the effluent concentration reached the input level [0081] iii) Stop flow followed by a 24-hour shut-in [0082] iv) Post flush the sand pack with brine monitoring effluent chemical tracer concentrations

[0083] Inhibitor Assay:

[0084] For comparison purposes, the chemical was functionalized in two ways to generate two separate species; one functionalized with a tracer for LFA analysis (Species 1: a hapten moiety coupled to a scale inhibitor) and the second functionalized with a fluorescent tracer (Species 2: a fluorescent moiety coupled to a scale inhibitor). Chemical tracer concentrations were quantified, for Species 1, using the method described in this patent and the fluorescent tracer Species 2 via fluorescence spectroscopy.

[0085] Sand Pack Flood Chemical Tracer Returns:

[0086] The effluent concentration profiles, for Species 1 and Species 2, produced from the sand packs during the brine post flush, for both floods, are shown in FIG. 4. Both chemical species show a steep decline in their effluent concentrations during the early brine post flush. After that, the concentration declines slowly. Both effluent chemical Species 1 and 2 exhibit similar profiles. This demonstrates the efficacy of using a LFA reader to quantify chemical species residuals.