CN114813591B - Method for detecting concentration of polymer - Google Patents
Method for detecting concentration of polymer Download PDFInfo
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- CN114813591B CN114813591B CN202110062600.0A CN202110062600A CN114813591B CN 114813591 B CN114813591 B CN 114813591B CN 202110062600 A CN202110062600 A CN 202110062600A CN 114813591 B CN114813591 B CN 114813591B
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- 229920000642 polymer Polymers 0.000 title claims abstract description 142
- 238000000034 method Methods 0.000 title claims abstract description 41
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 170
- 229910021645 metal ion Inorganic materials 0.000 claims abstract description 48
- 239000003431 cross linking reagent Substances 0.000 claims abstract description 32
- 238000002835 absorbance Methods 0.000 claims description 204
- 239000000243 solution Substances 0.000 claims description 200
- 239000012086 standard solution Substances 0.000 claims description 72
- 239000012088 reference solution Substances 0.000 claims description 42
- 239000002904 solvent Substances 0.000 claims description 21
- 238000012937 correction Methods 0.000 claims description 20
- 238000010790 dilution Methods 0.000 claims description 11
- 239000012895 dilution Substances 0.000 claims description 11
- 230000001105 regulatory effect Effects 0.000 claims description 10
- 230000004044 response Effects 0.000 claims description 9
- CMOAHYOGLLEOGO-UHFFFAOYSA-N oxozirconium;dihydrochloride Chemical group Cl.Cl.[Zr]=O CMOAHYOGLLEOGO-UHFFFAOYSA-N 0.000 claims description 8
- 238000007865 diluting Methods 0.000 claims description 7
- 239000003129 oil well Substances 0.000 claims description 7
- -1 zirconium ions Chemical class 0.000 claims description 7
- 238000006243 chemical reaction Methods 0.000 claims description 6
- PHFQLYPOURZARY-UHFFFAOYSA-N chromium trinitrate Chemical compound [Cr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O PHFQLYPOURZARY-UHFFFAOYSA-N 0.000 claims description 6
- 239000004971 Cross linker Substances 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- 229910001430 chromium ion Inorganic materials 0.000 claims description 5
- ZUGAOYSWHHGDJY-UHFFFAOYSA-K 5-hydroxy-2,8,9-trioxa-1-aluminabicyclo[3.3.2]decane-3,7,10-trione Chemical compound [Al+3].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O ZUGAOYSWHHGDJY-UHFFFAOYSA-K 0.000 claims description 4
- 125000003178 carboxy group Chemical group [H]OC(*)=O 0.000 claims description 4
- 238000004132 cross linking Methods 0.000 claims description 4
- GPRLSGONYQIRFK-UHFFFAOYSA-N hydron Chemical compound [H+] GPRLSGONYQIRFK-UHFFFAOYSA-N 0.000 claims description 4
- 238000005259 measurement Methods 0.000 claims description 4
- 229920002125 Sokalan® Polymers 0.000 claims description 3
- FPCJKVGGYOAWIZ-UHFFFAOYSA-N butan-1-ol;titanium Chemical compound [Ti].CCCCO.CCCCO.CCCCO.CCCCO FPCJKVGGYOAWIZ-UHFFFAOYSA-N 0.000 claims description 3
- 239000004584 polyacrylic acid Substances 0.000 claims description 3
- 229910052719 titanium Inorganic materials 0.000 claims 1
- 239000010936 titanium Substances 0.000 claims 1
- 229910052726 zirconium Inorganic materials 0.000 claims 1
- 238000001514 detection method Methods 0.000 abstract description 11
- 238000000605 extraction Methods 0.000 abstract description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 58
- OKIIEJOIXGHUKX-UHFFFAOYSA-L Cadmium iodide Inorganic materials [Cd+2].[I-].[I-] OKIIEJOIXGHUKX-UHFFFAOYSA-L 0.000 description 24
- 229940075417 cadmium iodide Drugs 0.000 description 19
- 230000002378 acidificating effect Effects 0.000 description 14
- 239000012153 distilled water Substances 0.000 description 14
- 239000004280 Sodium formate Substances 0.000 description 13
- 239000007853 buffer solution Substances 0.000 description 13
- 230000000052 comparative effect Effects 0.000 description 13
- HLBBKKJFGFRGMU-UHFFFAOYSA-M sodium formate Chemical compound [Na+].[O-]C=O HLBBKKJFGFRGMU-UHFFFAOYSA-M 0.000 description 13
- 235000019254 sodium formate Nutrition 0.000 description 13
- 239000003921 oil Substances 0.000 description 11
- QTBSBXVTEAMEQO-UHFFFAOYSA-N Acetic acid Chemical compound CC(O)=O QTBSBXVTEAMEQO-UHFFFAOYSA-N 0.000 description 10
- 239000000047 product Substances 0.000 description 10
- JGJLWPGRMCADHB-UHFFFAOYSA-N hypobromite Inorganic materials Br[O-] JGJLWPGRMCADHB-UHFFFAOYSA-N 0.000 description 8
- 230000008569 process Effects 0.000 description 8
- WKBOTKDWSSQWDR-UHFFFAOYSA-N Bromine atom Chemical class [Br] WKBOTKDWSSQWDR-UHFFFAOYSA-N 0.000 description 5
- 229960000583 acetic acid Drugs 0.000 description 5
- 239000012362 glacial acetic acid Substances 0.000 description 5
- 238000002347 injection Methods 0.000 description 5
- 239000007924 injection Substances 0.000 description 5
- LCKIEQZJEYYRIY-UHFFFAOYSA-N Titanium ion Chemical compound [Ti+4] LCKIEQZJEYYRIY-UHFFFAOYSA-N 0.000 description 4
- GBNDTYKAOXLLID-UHFFFAOYSA-N zirconium(4+) ion Chemical compound [Zr+4] GBNDTYKAOXLLID-UHFFFAOYSA-N 0.000 description 4
- 238000010438 heat treatment Methods 0.000 description 3
- 229920002401 polyacrylamide Polymers 0.000 description 3
- 238000001556 precipitation Methods 0.000 description 3
- 239000012085 test solution Substances 0.000 description 3
- 238000010521 absorption reaction Methods 0.000 description 2
- 238000000862 absorption spectrum Methods 0.000 description 2
- DIZPMCHEQGEION-UHFFFAOYSA-H aluminium sulfate (anhydrous) Chemical compound [Al+3].[Al+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O DIZPMCHEQGEION-UHFFFAOYSA-H 0.000 description 2
- 238000009835 boiling Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- 239000010779 crude oil Substances 0.000 description 2
- 238000006073 displacement reaction Methods 0.000 description 2
- 239000011521 glass Substances 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- 238000011084 recovery Methods 0.000 description 2
- 239000003440 toxic substance Substances 0.000 description 2
- 238000000870 ultraviolet spectroscopy Methods 0.000 description 2
- 238000011144 upstream manufacturing Methods 0.000 description 2
- 238000005303 weighing Methods 0.000 description 2
- BDKLKNJTMLIAFE-UHFFFAOYSA-N 2-(3-fluorophenyl)-1,3-oxazole-4-carbaldehyde Chemical compound FC1=CC=CC(C=2OC=C(C=O)N=2)=C1 BDKLKNJTMLIAFE-UHFFFAOYSA-N 0.000 description 1
- 229920002472 Starch Polymers 0.000 description 1
- 230000009471 action Effects 0.000 description 1
- 125000000129 anionic group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- VZJJZMXEQNFTLL-UHFFFAOYSA-N chloro hypochlorite;zirconium;octahydrate Chemical compound O.O.O.O.O.O.O.O.[Zr].ClOCl VZJJZMXEQNFTLL-UHFFFAOYSA-N 0.000 description 1
- 230000007797 corrosion Effects 0.000 description 1
- 238000005260 corrosion Methods 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000011161 development Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000000706 filtrate Substances 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 125000002887 hydroxy group Chemical group [H]O* 0.000 description 1
- 230000006872 improvement Effects 0.000 description 1
- 239000002973 irritant agent Substances 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 239000012452 mother liquor Substances 0.000 description 1
- 231100000252 nontoxic Toxicity 0.000 description 1
- 230000003000 nontoxic effect Effects 0.000 description 1
- 238000006116 polymerization reaction Methods 0.000 description 1
- 238000002360 preparation method Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 239000002994 raw material Substances 0.000 description 1
- 230000035945 sensitivity Effects 0.000 description 1
- 238000004904 shortening Methods 0.000 description 1
- 235000017281 sodium acetate Nutrition 0.000 description 1
- 229940087562 sodium acetate trihydrate Drugs 0.000 description 1
- 235000019698 starch Nutrition 0.000 description 1
- 239000008107 starch Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000002352 surface water Substances 0.000 description 1
- 231100000167 toxic agent Toxicity 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Classifications
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N21/00—Investigating or analysing materials by the use of optical means, i.e. using sub-millimetre waves, infrared, visible or ultraviolet light
- G01N21/17—Systems in which incident light is modified in accordance with the properties of the material investigated
- G01N21/25—Colour; Spectral properties, i.e. comparison of effect of material on the light at two or more different wavelengths or wavelength bands
- G01N21/31—Investigating relative effect of material at wavelengths characteristic of specific elements or molecules, e.g. atomic absorption spectrometry
-
- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N1/00—Sampling; Preparing specimens for investigation
- G01N1/28—Preparing specimens for investigation including physical details of (bio-)chemical methods covered elsewhere, e.g. G01N33/50, C12Q
- G01N1/38—Diluting, dispersing or mixing samples
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- Physics & Mathematics (AREA)
- Health & Medical Sciences (AREA)
- Life Sciences & Earth Sciences (AREA)
- Chemical & Material Sciences (AREA)
- Analytical Chemistry (AREA)
- Biochemistry (AREA)
- General Health & Medical Sciences (AREA)
- General Physics & Mathematics (AREA)
- Immunology (AREA)
- Pathology (AREA)
- Spectroscopy & Molecular Physics (AREA)
- Investigating Or Analyzing Non-Biological Materials By The Use Of Chemical Means (AREA)
- Investigating Or Analysing Materials By The Use Of Chemical Reactions (AREA)
Abstract
The application discloses a method for detecting polymer concentration, and belongs to the technical field of oilfield oil extraction. The embodiment of the application provides a method for detecting the concentration of a polymer, which only needs to add hydrochloric acid and a metal ion cross-linking agent solution into a solution to be detected when the concentration of the polymer in the solution to be detected is detected, so that only needs to prepare the hydrochloric acid and the metal ion cross-linking agent solution when the concentration of the polymer is detected, the time for preparing the solution is shortened, and the detection efficiency of the concentration of the polymer is improved.
Description
Technical Field
The application relates to the technical field of oil extraction in oil fields. In particular to a method for detecting the concentration of a polymer.
Background
In the technical field of oil extraction in oil fields, the recovery ratio of crude oil can be improved by adding an oil displacement agent into an oil well. Among them, polymers are commonly used oil-displacing agents. In the actual production process, when crude oil is extracted from an oil well, water is often also extracted. For wells where the oil recovery is increased by the addition of polymer, the polymer may be dissolved in the water so that the produced water contains the polymer. The oil displacement efficiency can be evaluated by measuring the concentration of the dissolved polymer in water, and a powerful support is provided for developing a scheme.
In the related art, the concentration of the polymer in water is mainly determined by a starch-cadmium iodide color development method. The method comprises the steps of firstly preparing saturated bromine water, preparing an acidic buffer solution, a sodium formate solution and a starch-cadmium iodide solution, then sequentially dripping the acidic buffer solution, the saturated bromine water, the sodium formate and the starch-cadmium iodide solution into a sample to be detected, keeping the color unchanged after the solution develops, measuring the absorbance of the sample to be detected by a spectrophotometer, and then determining the concentration of the polymer in the sample to be detected according to the relation between the absorbance and the concentration in a standard curve of the polymer.
However, in the related art, various solutions such as saturated bromine water, an acidic buffer solution, a sodium formate solution, a starch-cadmium iodide solution and the like need to be prepared when the concentration of the polymer is measured, which takes a long time and results in low detection efficiency of the concentration of the polymer.
Disclosure of Invention
The embodiment of the application provides a method for detecting polymer concentration, which can improve the detection efficiency of the polymer concentration. The specific technical scheme is as follows:
the embodiment of the application provides a method for detecting polymer concentration, which comprises the following steps:
obtaining a first reference solution with a first mass and obtaining a first to-be-tested solution with the first mass from a target oil well, wherein the first reference solution comprises a solvent, and the first to-be-tested solution comprises the solvent and a polymer containing carboxyl;
Adding hydrochloric acid into the first reference solution, regulating the pH value of the hydrogen ion concentration index of the first reference solution to a preset pH value through the hydrochloric acid to obtain a second reference solution, adding the hydrochloric acid into the first solution to be tested, and regulating the pH value of the first solution to the preset pH value through the hydrochloric acid to obtain a second solution to be tested;
determining to consume a second mass of the hydrochloric acid when the pH of the first solution to be tested is adjusted to the preset pH;
Adding a metal ion cross-linking agent solution into the second solution to be tested according to the volume ratio of 1:1 to obtain a third solution to be tested, wherein the metal ion cross-linking agent solution is used for carrying out cross-linking reaction with a polymer in the second solution to be tested;
Measuring a first absorbance of the third solution to be measured and a second absorbance of the second reference solution at a first wavelength, respectively, wherein the second absorbance of the second reference solution is used as a reference, and the influence of the solvent on the measurement of the absorbance of the polymer is removed;
And determining the first concentration of the polymer in the first solution to be tested according to the first absorbance, the second absorbance, a pre-acquired standard curve function of the polymer, the first mass and the second mass, wherein the standard curve function is used for reflecting the relation between the concentration of the polymer and the absorbance.
In one possible implementation manner, the determining the first concentration of the polymer in the first solution to be tested according to the first absorbance, the second absorbance, a pre-acquired standard curve function of the polymer, the first mass and the second mass includes:
Determining a correction coefficient according to the first quality and the second quality;
Determining a second concentration of the polymer based on the first absorbance, the second absorbance, and the standard curve function;
Taking the product of the correction coefficient and the second concentration as a first concentration of the polymer in the first solution to be tested.
In another possible implementation manner, the determining a correction coefficient according to the first quality and the second quality includes:
determining the sum of the first mass and the second mass to obtain a third mass;
And determining a ratio of the third mass to the first mass, and taking the ratio as the correction coefficient.
In another possible implementation, the determining the second concentration of the polymer according to the first absorbance, the second absorbance, and the standard curve function includes:
Determining a target absorbance from the first absorbance and the second absorbance in response to the first absorbance being less than 1; substituting the target absorbance into the standard curve function to obtain a target concentration corresponding to the target absorbance, and taking the target concentration as a second concentration of the polymer;
In response to the first absorbance not less than 1, diluting the first solution to be tested to obtain a fourth solution to be tested, taking the fourth solution to be tested as the first solution to be tested, executing the step of adding the hydrochloric acid into the first solution to be tested, and adjusting the pH value of the first solution to be tested to the preset pH value through the hydrochloric acid to obtain a second solution to be tested until the first absorbance is less than 1; determining the target absorbance according to the first absorbance and the second absorbance; substituting the target absorbance into the standard curve function to obtain a target concentration corresponding to the target absorbance; determining the dilution factor of diluting the first solution to be tested; and taking the product of the target concentration and the dilution multiple as the second concentration.
In another possible implementation manner, the determining the target absorbance according to the first absorbance and the second absorbance includes:
Determining a difference between the first absorbance and the second absorbance;
And taking the difference value as the target absorbance.
In another possible implementation, the method further includes:
preparing a plurality of first standard solutions of polymers with different concentrations;
Adding the hydrochloric acid into the first standard solution with each concentration, and adjusting the pH value of the first standard solution with each concentration to the preset pH value through the hydrochloric acid to obtain a second standard solution with a plurality of concentrations;
Adding the metal ion cross-linking agent solution into the second standard solutions according to the volume ratio of 1:1 to obtain a plurality of third standard solutions;
Measuring, by the spectrophotometer, a third absorbance of the plurality of third standard solutions at the first wavelength;
obtaining a second absorbance of the second reference solution;
And obtaining the standard curve function through linear fitting according to the second absorbance, the third absorbance of each third standard solution and the corresponding concentration.
In another possible implementation, the determining to consume the second mass of the hydrochloric acid when adjusting the pH of the first solution to be tested to the preset pH value includes:
Determining the sum of the mass of the container containing the hydrochloric acid and the mass of the hydrochloric acid before adjusting the pH value of the first solution to be tested to obtain a fourth mass;
determining the sum of the masses of the container and the residual hydrochloric acid in the container when the pH value of the first solution to be tested is regulated to the preset pH value, and obtaining a fifth mass;
taking the difference between the fourth mass and the fifth mass as a second mass consuming the hydrochloric acid.
In another possible implementation, the polymer is at least one of polyacrylamide and polyacrylic acid.
In another possible implementation, the metal ion in the metal ion crosslinker solution is a zirconium ion, an aluminum ion, a chromium ion, or a titanium ion.
In another possible implementation, the metal ion crosslinker is zirconium oxychloride, aluminum citrate, chromium nitrate, or butyl titanate.
The technical scheme provided by the embodiment of the application has the beneficial effects that:
According to the method for detecting the concentration of the polymer, disclosed by the embodiment of the application, when the concentration of the polymer in the solution to be detected is detected, only hydrochloric acid and the metal ion cross-linking agent solution are needed to be added into the solution to be detected, so that when the concentration of the polymer is detected, only the hydrochloric acid and the metal ion cross-linking agent solution are needed to be prepared, the time for preparing the solution is shortened, and the detection efficiency of the concentration of the polymer is improved.
Drawings
Fig. 1 is a flowchart of a method for detecting a polymer concentration according to an embodiment of the present application.
Detailed Description
In order to make the technical scheme and advantages of the present application more clear, the following further describes the embodiments of the present application in detail.
The embodiment of the application provides a method for detecting polymer concentration, referring to fig. 1, the method comprises the following steps:
Step 101: a first reference solution of a first mass is obtained and a first solution to be tested of the first mass is obtained from a target well.
In this step, the first reference solution includes a solvent, the first solution to be tested includes a solvent and a polymer containing carboxyl groups, and the first solution to be tested is obtained from a target well using polymer flooding. The polymer can be at least one of polyacrylamide and polyacrylic acid, and the solvent is produced water produced from a target oil well.
The first quality may be set and modified as needed, and in the embodiment of the present application, this is not particularly limited. For example, the first mass is 5g or 10g.
In the embodiment of the application, the first reference solution is mainly used for eliminating the influence of the solvent on the absorbance of the measured polymer, so that the concentration of the polymer in the first solution to be measured can be measured more accurately, errors are reduced, and the accuracy of polymer detection is improved.
Step 102: adding hydrochloric acid into the first reference solution, adjusting the pH value of the first reference solution to a preset pH value through the hydrochloric acid to obtain a second reference solution, adding the hydrochloric acid into the first solution to be tested, and adjusting the pH value of the first solution to be tested to the preset pH value through the hydrochloric acid to obtain the second solution to be tested.
In this step, 5% strength hydrochloric acid may be used to adjust the pH (Hydrogen ion concentration, hydrogen ion concentration index) values of the first reference solution and the first test solution.
In the embodiment of the application, the polymer and the metal ion cross-linking agent are subjected to cross-linking reaction to easily generate precipitation, and the precipitation cannot be generated in an acidic environment. Therefore, before the first to-be-detected solution reacts with the metal ion crosslinking agent, the pH value of the first to-be-detected solution is adjusted to an acidic environment through hydrochloric acid, so that generation of precipitation is avoided, and the measurement of absorbance is influenced. The first reference solution is also adjusted to the preset pH value through the hydrochloric acid, so that the influence of the hydrochloric acid on the absorbance of the polymer in the subsequent measurement of the absorbance of the polymer can be eliminated, and the accuracy of measuring the absorbance of the polymer is improved.
The preset pH may be set and modified as needed, for example, the preset pH may be any value between 3.5 and 4.5, and the value may be 3.5, 4, or 4.5.
Step 103: and determining that the second mass of the hydrochloric acid is consumed when the pH value of the first solution to be tested is regulated to a preset pH value.
In this step, the second mass of hydrochloric acid consumed is determined while the pH of the first solution to be tested is adjusted to a preset pH.
In one possible implementation, the second mass of consumed hydrochloric acid may be determined based on the mass of hydrochloric acid before adjusting the pH of the first solution to be tested and the remaining mass of hydrochloric acid after adjusting the pH. The process may be: determining the sum of the mass of the container containing hydrochloric acid and the mass of hydrochloric acid before adjusting the pH value of the first solution to be tested to obtain fourth mass; determining the sum of the masses of the container and the residual hydrochloric acid in the container when the pH value of the first solution to be tested is regulated to a preset pH value, and obtaining a fifth mass; the difference between the fourth mass and the fifth mass is taken as the second mass consuming hydrochloric acid.
In this implementation, the container may be a beaker. Correspondingly, when the container is a beaker, the total mass of the beaker and the hydrochloric acid is weighed before adjusting the pH value, so as to obtain a fourth mass. After adjusting the pH value, weighing the total mass of the beaker and the residual hydrochloric acid in the beaker to obtain a fifth mass, and taking the difference value of the total mass and the residual mass as a second mass of consumed hydrochloric acid.
In another possible implementation, the second mass of hydrochloric acid may also be determined from the volume and density of hydrochloric acid consumed. The process may be: determining the volume of consumed hydrochloric acid when the pH value of the first solution to be tested is regulated to a preset pH value; measuring the density of hydrochloric acid; the product of the volume and density of hydrochloric acid is taken as the second mass of consumed hydrochloric acid.
In this implementation manner, when the pH value of the first solution to be measured is adjusted, the first volume of hydrochloric acid may be measured by the measuring cylinder, and when the pH value of the first solution to be measured is adjusted to a preset pH value, the second volume of the remaining hydrochloric acid is measured by the measuring cylinder, and the difference between the first volume and the second volume is used as the volume of consumed hydrochloric acid. The density of hydrochloric acid was measured by a densitometer, and then the product of the volume of hydrochloric acid and the density was determined as the second mass of hydrochloric acid.
In embodiments of the application, the second mass of hydrochloric acid consumed may be determined by either means. In the embodiment of the present application, this is not particularly limited.
Step 104: and adding a metal ion cross-linking agent solution into the second solution to be detected according to the volume ratio of 1:1 to obtain a third solution to be detected.
In this step, the metal ion in the metal ion crosslinker solution may be a zirconium ion, an aluminum ion, a chromium ion, or a titanium ion.
When the metal ion is a zirconium ion, the metal ion crosslinking agent may be zirconium oxychloride;
When the metal ion is an aluminum ion, the metal ion crosslinking agent may be aluminum citrate;
when the metal ion is a chromium ion, the metal ion crosslinking agent may be chromium nitrate;
When the metal ion is a titanium ion, the metal ion crosslinking agent may be butyl titanate.
In the embodiment of the application, the metal ion is a metal ion in a high valence state, for example, chromium ion and aluminum ion are trivalent, and titanium ion and zirconium ion are tetravalent.
It should be noted that, in the related art, when the polymer concentration in the produced water is measured by a starch-cadmium iodide chromogenic method, bromine water is used, and the bromine water is a toxic substance, which is harmful to laboratory personnel and the environment. In addition, the acid buffer solution is prepared by adopting glacial acetic acid and aluminum sulfate in the related technology, and the glacial acetic acid is easy to volatilize and can cause harm to experimental personnel and environment. The metal ion cross-linking agents used in the embodiment of the application, such as zirconium oxychloride, aluminum citrate and the like, are non-toxic substances and are not easy to volatilize, so that the harm to experimental personnel and the environment can be avoided. In addition, zirconium oxychloride and the polymer can completely react in 4 minutes at normal temperature, and the reaction time is short, so that the detection efficiency of the concentration of the polymer can be greatly improved.
In this step, after adding the metal ion cross-linking agent solution to the second solution to be measured, the solution may be stirred for 2 minutes by a glass rod and then left for 15 minutes to allow the polymer in the second solution to be measured to sufficiently react with the metal ions in the metal ion cross-linking agent solution, and then step 105 is performed.
In one possible implementation, the concentration of the metal ion crosslinker solution may be set and modified as desired, for example, 100mg/L, 150mg/L, or 200mg/L. In the embodiment of the present application, this is not particularly limited.
Another point is that the polymer has an absorption peak of about 200nm in the ultraviolet-visible absorption spectrum, but the absorbance measured is low, and when the concentration of the polymer in water is low, the polymer is not easily detected, and the error is large. According to the application, the metal ion cross-linking agent is added into the solution to be detected, and the carboxyl of the polymer and the metal ion with high valence state are subjected to cross-linking reaction under the action of the hydroxyl in water, so that the absorption peak of the solution to be detected on an ultraviolet-visible absorption spectrum chart is subjected to red shift, and the absorbance at the first wavelength is larger. The concentration of the polymer in water can be accurately measured by the method under the condition that the absorbance and the concentration of the polymer are in linear relation.
Step 105: and respectively measuring the first absorbance of the third solution to be measured and the second absorbance of the second reference solution at the first wavelength.
In this step, the second absorbance of the second reference solution is used as a reference, and the effect of the solvent removal on the measured polymer absorbance is measured. Accordingly, the target absorbance may be determined based on the first absorbance of the third solution to be measured and the second absorbance of the second reference solution. The process may be: and determining a difference value between the first absorbance of the third solution to be detected and the second absorbance of the second reference solution, and taking the difference value as a target absorbance.
In the implementation manner, the first absorbance of the third solution to be measured is the sum of the absorbance of the polymer and the absorbance of the solvent, and the second absorbance of the second reference solution is the absorbance of the solvent, so that the difference between the first absorbance of the third solution to be measured and the second absorbance of the second reference solution is the target absorbance of the polymer. Wherein, the second absorbance may be represented by A, the first absorbance may be represented by A m, and the target absorbance is (A m -A).
It should be noted that, before this step, the first wavelength needs to be determined. Wherein the first wavelength can be determined by measuring the absorbance of the third test solution of different concentrations at different wavelengths by a spectrophotometer. The process may be: preparing a plurality of first standard solutions of polymers with different concentrations; scanning the wavelength of the first standard solution with each concentration to obtain the absorbance corresponding to the first standard solution with the concentration under different wavelengths; determining the slope of a linear curve corresponding to the same wavelength according to the concentration and the absorbance corresponding to the concentration at the same wavelength; and taking the wavelength corresponding to the maximum slope as the first wavelength according to different wavelengths and the slope corresponding to each wavelength. In an embodiment of the application, the first wavelength is 225nm according to the method.
In one possible implementation, the first standard solution with different concentration may be obtained by preparing the third standard solution with higher concentration by a solvent, i.e. produced water, and then diluting the third standard solution by different multiples. The process may be: taking a first volume of produced water, adding a fourth mass of polymer into the produced water, preparing a third standard solution of 100mg/L, measuring different volumes of the third standard solution, and then adding the produced water for dilution to obtain a first standard solution of 20mg/L, 50mg/L, 80mg/L and 100mg/L respectively. In this implementation, the 0mg/L first standard solution is produced water that does not contain polymer.
In this step, the spectrophotometer is an ultraviolet-visible spectrophotometer. The model of the uv-vis spectrophotometer may be set and changed as needed, and in the embodiment of the present application, this is not particularly limited. For example, the ultraviolet-visible spectrophotometer is model UV-160.
Step 106: and determining the first concentration of the polymer in the first solution to be tested according to the first absorbance, the second absorbance, the standard curve function of the polymer acquired in advance, the first mass and the second mass.
Wherein the standard curve function is used to reflect the relationship between the concentration of the polymer and the absorbance. In this step, the second concentration of the polymer in the second solution to be measured may be determined according to the target absorbance and the standard curve function, the correction coefficient may be determined according to the first mass of the first solution to be measured and the second mass of the hydrochloric acid, and the first concentration of the polymer in the first solution to be measured may be determined according to the second concentration of the polymer in the second solution to be measured and the correction coefficient. Accordingly, the process may be achieved by the following steps (1) to (3), including:
(1) And determining a correction coefficient according to the first quality and the second quality.
In this step, the sum of the first mass and the second mass may be determined first to obtain a third mass; a ratio of the third mass to the first mass is then determined and used as a correction factor.
In this step, the first mass may be represented by m 0, the second mass may be represented by m 1, and the correction coefficient may be represented by b, then b= (m 0+m1)/m0).
(2) A second concentration of the polymer is determined based on the first absorbance, the second absorbance, and the standard curve function.
In this step, the first absorbance measured by the spectrophotometer may be greater than 1, or may be less than 1.
In response to the first absorbance being less than 1, a second concentration of the polymer may be determined by the following steps (2-1) to (2-2), comprising:
(2-1) determining a target absorbance from the first absorbance and the second absorbance in response to the first absorbance being less than 1.
In this step, a difference between the first absorbance and the second absorbance may be determined, and the difference may be regarded as the target absorbance.
(2-2) Substituting the target absorbance into the standard curve function to obtain a target concentration corresponding to the target absorbance, and taking the target concentration as a second concentration of the polymer.
In this step, the standard curve function may reflect the relationship between the concentration of the polymer and the absorbance, and substituting the target absorbance into the function may obtain the target concentration corresponding to the target absorbance, that is, the second concentration.
In response to the first absorbance not being less than 1, a second concentration of the polymer may be determined by the following steps (2-3) to (2-4), comprising:
(2-3) diluting the first solution to be tested in response to the first absorbance not less than 1 to obtain a fourth solution to be tested.
In this step, a solvent may be added to the first solution to be tested, i.e., produced water may be used to dilute the first solution to be tested.
(2-4) Taking the fourth solution to be measured as the first solution to be measured, adding hydrochloric acid into the first solution to be measured, regulating the pH value of the first solution to be measured to a preset pH value through the hydrochloric acid to obtain a second solution to be measured, then determining the second mass of consumed hydrochloric acid, adding a metal ion cross-linking agent solution into the second solution to be measured according to the volume ratio of 1:1 to obtain a third solution to be measured, and measuring the first absorbance of the third solution to be measured under the first wavelength by a spectrophotometer until the first absorbance is smaller than 1; determining a target absorbance according to the first absorbance and the second absorbance; substituting the target absorbance into a standard curve function to obtain a target concentration corresponding to the target absorbance; and determining the dilution multiple of the diluted first solution to be tested, and taking the product of the target concentration and the dilution multiple as the second concentration.
In the embodiment of the application, when the first absorbance is not less than 1, if the target absorbance is directly determined according to the first absorbance and the second absorbance, substituting the target absorbance into the standard curve function can cause larger error and inaccurate concentration of the obtained polymer. The first solution to be measured may then be diluted by a solvent and then steps 102-105 described above may be re-performed until the measured first absorbance is less than 1. Wherein the second concentration measured when the first absorbance is less than 1 can be represented by C 0. When the first absorbance is not less than 1, the target concentration measured after dilution may be represented by C 1, the dilution multiple may be represented by n, and the second concentration C 0＝C1 ×n.
(3) And taking the product of the correction coefficient and the second concentration as the first concentration of the polymer in the first solution to be tested.
In this step, the product of the correction factor and the second concentration is determined and used as the first concentration of the polymer in the first solution to be tested.
In the embodiment of the application, hydrochloric acid is added into a first solution to be measured in a solution form, and the first solution to be measured is diluted, so that the target absorbance obtained by measuring through a spectrophotometer is the absorbance corresponding to the polymer in a second solution to be measured, and the target concentration obtained after substituting the target absorbance into a standard curve function is the second concentration of the polymer in the second solution to be measured. The correction factor in step (1) is a multiple of the dilution of the first solution to be measured, so that the first concentration of the polymer in the first solution to be measured is the product of the second concentration of the polymer in the second solution to be measured and the correction factor. The first concentration may be represented by C, then c=c 0 ×b.
It should be noted that, before this step, a standard curve function needs to be determined. Wherein the standard curve function can be determined by the following steps (1) to (6):
(1) A plurality of first standard solutions of different concentrations of the polymer are formulated.
In this step, the concentration of the plurality of first standard solutions is the same as the concentration of the plurality of first standard solutions when the first wavelength is determined in the step 105, so that the plurality of first standard solutions with different concentrations prepared in the step 105 when the first wavelength is determined can be directly obtained in this step, thereby shortening the time for preparing the standard solutions and improving the detection efficiency of the polymer concentration.
(2) And adding hydrochloric acid into the first standard solution with each concentration, and adjusting the pH value of the first standard solution with each concentration to a preset pH value through the hydrochloric acid to obtain a plurality of second standard solutions.
The process of adjusting the pH of the first standard solution with any concentration by hydrochloric acid is similar to the above step 102, and will not be described herein.
(3) And adding a metal ion cross-linking agent solution into the second standard solution with each concentration according to the volume ratio of 1:1 to obtain a plurality of third standard solutions.
In this step, the same volume of the second standard solution of different concentrations may be measured, and then the volume of the metal ion crosslinking agent solution is added to each concentration of the second standard solution, stirred with a glass rod for 2 minutes, and then left for 15 minutes, thereby obtaining a plurality of third standard solutions.
Wherein, the concentration of the metal ion cross-linking agent solution in the step is the same as the concentration of the metal ion cross-linking agent solution added to the second solution to be tested in the step 104, and the concentration can be 100mg/L.
(4) The third absorbance of the plurality of third standard solutions is measured by a spectrophotometer at the first wavelength.
In this step, the third absorbance of the plurality of second standard solutions is measured by a spectrophotometer at 225 nm. The plurality of third absorbance values may be represented by a 0、A1、A2、A3、A4, respectively.
(5) A second absorbance of a second reference solution is obtained.
In an embodiment of the present application, when the standard curve function is determined prior to step 105, the second absorbance of the second reference solution may be measured by a spectrophotometer at the first wavelength. This way, the second absorbance may be directly obtained when performing step 105. When the standard curve function is determined before step 106, in this step, the second absorbance of the second reference solution measured in step 105 may be directly acquired. Wherein the second absorbance of the second reference solution was measured to be 0.0045, the specific data can be seen in table 1.
In the embodiment of the present application, the timing of obtaining the second absorbance of the second reference solution is not particularly limited. Wherein the second absorbance of the second reference solution may be denoted by a.
(6) And obtaining a standard curve function through linear fitting according to the second absorbance, the third absorbance of each third standard solution and the corresponding concentration.
In this step, a difference between the third absorbance and the second absorbance of each third standard solution may be determined, resulting in a plurality of fourth absorbance, which may be expressed as: (A 0-A)、(A1-A)、(A2-A)、(A3-A)、(A4 -A).
Based on the linear relation between the absorbance and the concentration, a straight line of the corresponding relation between the fourth absorbance and the concentration of the third standard solution can be obtained, and then a standard curve function can be obtained through linear fitting, wherein the standard curve function can be as follows: x= (y-a)/t, where y represents the target absorbance, x represents the second concentration of the polymer, and a and t are both constants. The square value of the correlation coefficient of the standard curve function is greater than a preset threshold value, which can be set and changed as required, for example, the preset threshold value is 0.99 or 0.98.
The embodiment of the application provides a method for detecting the concentration of a polymer, which only needs to add hydrochloric acid and a metal ion cross-linking agent solution into a solution to be detected when the concentration of the polymer in the solution to be detected is detected, so that only needs to prepare the hydrochloric acid and the metal ion cross-linking agent solution when the concentration of the polymer is detected, the time for preparing the solution is shortened, and the detection efficiency of the concentration of the polymer is improved.
In addition, when the metal ion cross-linking agent solution is zirconium oxychloride, the metal ion cross-linking agent solution can completely react with the polymer in only 4 minutes at normal temperature, the reaction time is short, the reaction condition is mild, and the detection step is simple and rapid.
In addition, the method has high sensitivity and wide detection range, and can be used for detecting the concentration of the polymer in the oilfield produced water and also used for detecting reinjection water and surface water.
Moreover, the method is safe and environment-friendly, and does not need strong corrosion and volatile irritant agents such as bromine water, glacial acetic acid and the like in the measuring process.
The technical scheme of the application will be described in detail through specific examples.
In the following specific examples, the operations involved were performed under conventional conditions or conditions recommended by the manufacturer, without specifying the conditions. The raw materials used are not specified by the manufacturer and the specification are all conventional products which can be obtained by commercial purchase.
The polymers used in the standard curve functions determined in examples 1-3 and comparative examples 1-3 are anionic polyacrylamide, the model number is BHHP-113, the product standard Q/12DGY is 3865-2014, the molecular weight is more than or equal to 2500 ten thousand, and the polymer is produced by the Port oil field Port company;
Zirconium oxychloride octahydrate, analytically pure, commercially available.
Example 1
This example was conducted primarily to determine the concentration of polymer in the produced water from an oil well in the Gangdong injection zone of a large harbor oilfield, with Gangdong injection zone reinjection water containing no polymer.
Step 1: a standard curve function is determined.
(1) Zirconium oxychloride solutions with the concentration of 100mg/L and first standard solutions with the concentrations of 0mg/L, 20mg/L, 50mg/L, 80mg/L and 100mg/L are prepared by reinjection water.
(2) And 5% hydrochloric acid is added into the first standard solution with each concentration, and the pH value of the first standard solution with each concentration is adjusted to 4.5 through 5% hydrochloric acid, so that a plurality of second standard solutions with the concentrations are obtained.
(3) And adding 100mg/L of metal ion cross-linking agent solution into the second standard solution with each concentration according to the volume ratio of 1:1 to obtain a plurality of third standard solutions, and respectively measuring the third absorbance of the plurality of third standard solutions at 225nm, wherein the specific data are shown in Table 1.
TABLE 1 third absorbance and concentration of third standard solutions of different concentrations
(4) 5% Hydrochloric acid was added to the first reference solution, the pH of the first reference solution was adjusted to 4.5 by hydrochloric acid to obtain a second reference solution, and the second absorbance a of the second reference solution at 225nm was measured, for specific data, see table 1.
(5) The standard curve function is obtained according to the data: x= (y-0.0002)/0.0014, where R 2 = 0.9952, y is the target absorbance and x is the second concentration of polymer.
Step 2: and (3) obtaining a first solution to be tested, wherein the first solution is 5g in mass, adding 5% hydrochloric acid into the first solution to be tested, and adjusting the pH value of the first solution to be tested to 4.5 through the hydrochloric acid to obtain a second solution to be tested.
Step 3: when it was confirmed that the pH of the first solution to be measured was adjusted to 4.5, the second mass of hydrochloric acid consumed was 0.02g.
Step 4: adding 100mg/L zirconium oxychloride solution into the second solution to be detected according to the volume ratio of 1:1, uniformly stirring, and standing for 15min to obtain a third solution to be detected.
Step 5: the first absorbance of the third test solution was measured by a spectrophotometer at 225nm to be 1.0562.
Step 6: and in response to the first absorbance being greater than 1, diluting the first solution to be tested by 3 times by adopting reinjection water to obtain a fourth solution to be tested. And (3) taking the fourth solution to be detected as the first solution to be detected, re-executing the step (2-5), and measuring to obtain the first absorbance 0.0239.
The target absorbance was determined to be 0.0194 based on the first absorbance 0.0239 and the second absorbance 0.0045. Substituting the target absorbance into a standard curve function to obtain the third concentration C 1 which is 13.7143mg/L.
Then the second concentration C 0＝C1 x n= 13.7143 x 3= 41.1429mg/L.
When the above steps 2 to 5 were re-performed, the second mass of the consumed hydrochloric acid was 0.6g, and the correction coefficient b was determined to be 1.12.
The first concentration c=c 0 ×b= 41.1429 ×1.12= 46.0800mg/L, i.e. the concentration of polymer in the produced water of the well is 46.0800mg/L.
The total time for determining the polymer concentration by the above procedure was 38min.
Comparative example 1
The comparative example also measures the concentration of polymer in the produced water of an oil well in the Gangdong injection polymerization zone of a large harbor oil field, and the solvent is reinjection water.
Step1: preparing an acidic buffer solution, a starch-cadmium iodide solution and a sodium formate solution.
(1) An acidic buffer solution is prepared.
25G of sodium acetate trihydrate crystals are weighed into a 1000mL beaker and dissolved by adding about 800mL of distilled water.
To the beaker, 10mL of glacial acetic acid and 0.75g of aluminum sulfate were added to dissolve.
The pH value of the solution was measured by a pH meter, and the pH value of the solution was adjusted to 3.5 by glacial acetic acid to obtain an acidic buffer solution.
(2) Preparing starch-cadmium iodide solution.
Weighing 11.0g of cadmium iodide in a 1000mL beaker, adding 300-400 mL of distilled water, heating and boiling for 15min to dissolve the cadmium iodide, and continuously adding a little distilled water during the period to maintain the volume unchanged. About 600mL of distilled water was added and boiled again with heating.
2.5G of soluble starch was weighed into a 50mL beaker, dissolved with a small amount of distilled water, and added to the above cadmium iodide solution.
A50 mL beaker was rinsed 3 times with a small amount of distilled water, and the rinse was also poured into the cadmium iodide solution described above.
And heating and boiling the cadmium iodide solution for 5min, filtering with filter paper after the solution is completely cooled, putting the filtrate into a 1000mL volumetric flask, washing the filter with distilled water, adding distilled water to the scale, and shaking uniformly to obtain the starch-cadmium iodide solution.
(3) Preparing sodium formate solution.
10G of sodium formate is weighed, dissolved in 600ml of distilled water, transferred to a 1000ml volumetric flask, and then diluted to a scale mark to obtain sodium formate solution.
Step 2: a standard curve function is determined.
(1) Standard solutions of 0mg/L, 25mg/L, 50mg/L, 85mg/L and 100mg/L were prepared with reinjection water.
This step may be followed by preparation of 1000mg/L of the polymer mother liquor and dilution to 100mg/L of the standard solution. Standard solutions of 0, 0.5, 1.0, 1.7 and 2.0mL are respectively placed in a 50mL colorimetric tube, 5mL of acidic buffer solution is added, and reinjection water is added to dilute the solution to 30mL, so that standard solutions with different concentrations are obtained.
(2) To each concentration of standard solution was added 1mL of saturated bromine water, shaken well and left to react for 15min.
(3) To the solution of step (2) was added 5mL of 1% sodium formate, shaken well and left to react for 5min.
(4) And (3) adding 5mL of starch-cadmium iodide solution into the solution in the step (3), shaking uniformly and standing for reaction for 20min.
(5) The absorbance of each solution in step (4) was first adjusted to zero with reinjection water at a wavelength of 590nm, and then the absorbance was measured, as detailed data in table 2.
TABLE 2 absorbance of standard solutions of different concentrations and their concentrations
| Standard solution concentration (mg/L) | 0 | 25 | 50 | 85 | 100 |
| Absorbance (A) | 0 | 0.113 | 0.225 | 0.399 | 0.442 |
From the data in table 2, the standard curve function is obtained as: x= (y-0.0007)/0.0045, where R 2 = 0.9977.
Step 3: obtaining distilled water, reinjection water and 2mL of a solution to be detected respectively in a 50mL colorimetric tube, adding 5mL of an acidic buffer solution into the distilled water, reinjection water and the solution to be detected respectively, adding reinjection water to dilute the solution to 30mL, adding 1mL of saturated bromine water, shaking up and standing for 15min, adding 5mL of sodium formate, shaking up and standing for 5min, finally adding 5mL of starch-cadmium iodide solution, shaking up and standing for reacting for 20min, and obtaining the dye.
Step 4: the absorbance of the spectrophotometer was adjusted by distilled water at a wavelength of 590nm, and then the concentration of the reinjection water was measured to be 1.26mg/L and the concentration of the solution obtained in step 3 was measured to be 47.19mg/L, respectively.
Step 5: the concentration of the polymer in the solution to be tested was (47.19-1.26) mg/L=45.93 mg/L.
The total time for determining the polymer concentration by the above procedure was 135min.
Example 2
The concentration of the polymer in reinjection water of the combined station of the oil field Gangdong in the harbor is mainly measured, the solvent is produced water which is not subjected to polymer injection well over 5 years of the block history of the combined station Gangdong, and the produced water does not contain the polymer.
Step 1: a standard curve function is determined.
The step of determining the standard curve function in this step is similar to the step of determining the standard curve function in embodiment 1, and will not be described here. Wherein the pH value of the first standard solution is 4.1.
The absorbance of the first reference solution, the third absorbance of the third standard solution of different concentrations, and the concentration thereof measured in this step can be referred to in table 3.
TABLE 3 third absorbance and concentration of third standard solutions of different concentrations
The standard curve function is obtained according to the data: x= (y-0.007)/0.0025, where R 2 = 0.9972, y is the target absorbance and x is the second concentration of polymer.
In this embodiment, the steps 2-5 are similar to the steps 2-5 in embodiment 1, and will not be described again.
However, the second mass of hydrochloric acid consumed in this step was 0.04g, and the correction factor was determined to be 1.008. And measuring the first absorbance of the third solution to be measured to be 0.0365 and the second absorbance of the third solution to be measured to be 0.0024, wherein the target absorbance is 0.0341, and substituting the target absorbance into a standard curve function to obtain the second concentration C 0 to be 10.84mg/L.
The first concentration c=c 0 ×b=10.84×1.008=10.93 mg/L, i.e. the concentration of polymer in the produced water of the well is 10.93mg/L.
The total time for determining the polymer concentration by the above procedure was 35min.
Comparative example 2
The comparative example also measured the concentration of polymer in reinjection water from the water-pumping station of the oil field Gangdong in the harbor, the solvent was produced water from a well where no polymer injection was performed for 5 years in the area where the Gangdong unit was located.
Step1: preparing an acidic buffer solution, a starch-cadmium iodide solution and a sodium formate solution.
This step is the same as the step of preparing the acidic buffer solution, the starch-cadmium iodide solution and the sodium formate solution in comparative example 1, and will not be described again here.
Step 2: a standard curve function is determined.
This step is similar to the step of determining the standard curve function in comparative example 1, and will not be described again here.
The absorbance of the standard solutions of different concentrations measured in this step can be seen in table 4.
TABLE 4 absorbance of standard solutions of different concentrations and their concentrations
| Standard solution concentration (mg/L) | 0 | 25 | 50 | 85 | 100 |
| Absorbance (A) | 0 | 0.213 | 0.361 | 0.542 | 0.751 |
From the data in table 4, the standard curve function is obtained as: x= (y-0.0121)/0.0069, where R 2 = 0.9806.
Step3 is the same as step3 in comparative example 1, and will not be described again here.
Step 4: the absorbance of the spectrophotometer was adjusted by distilled water at a wavelength of 590nm, and then the concentration of the produced water was measured to be 1.13mg/L and the concentration of the solution obtained in step 3 was measured to be 11.65mg/L, respectively.
Step 5: the concentration of the polymer in the solution to be tested was (11.65-1.13) mg/L=10.52 mg/L.
The total time for determining the polymer concentration by the above procedure was 108min.
Example 3
The concentration of the polymer in a ditch near the West New 51-6 well of the great harbor oilfield is mainly measured, and the solvent is a water sample 5 km upstream of the ditch, and the water sample does not contain the polymer.
Step 1: a standard curve function is determined.
The step of determining the standard curve function in this step is similar to the step of determining the standard curve function in embodiment 1, and will not be described here. Wherein the pH value of the first standard solution is 4.
The absorbance of the first reference solution, the third absorbance of the third standard solution of different concentrations, and the concentration thereof measured in this step can be referred to in table 5.
TABLE 5 third absorbance and concentration of third standard solutions of different concentrations
The standard curve function is obtained according to the data: x= (y-0.0022)/0.0025, where R 2 = 0.9941, y is the target absorbance, x is the second concentration of polymer.
In this embodiment, the steps 2-5 are similar to the steps 2-5 in embodiment 1, and will not be described again.
However, the second mass of hydrochloric acid consumed in this step was 0.07g, and the correction factor was determined to be 1.014. And (3) measuring the first absorbance of the third solution to be measured to be 0.0135, and the second absorbance of the third solution to be measured to be 0.0003, wherein the target absorbance is 0.0132, and substituting the target absorbance into a standard curve function to obtain the second concentration C 0 of 4.4mg/L.
The first concentration c=c 0 ×b=4.4×1.014= 4.4616mg/L, i.e. the concentration of polymer in the produced water of the well is 4.4616mg/L.
The total time for determining the polymer concentration by the above procedure was 39min.
Comparative example 3
The comparative example was also performed to determine the concentration of polymer in a trench near West New 51-6 well in the Dagang oilfield, with solvent being a water sample 5 km upstream of the trench, which is free of polymer.
Step1: preparing an acidic buffer solution, a starch-cadmium iodide solution and a sodium formate solution.
This step is the same as the step of preparing the acidic buffer solution, the starch-cadmium iodide solution and the sodium formate solution in comparative example 1, and will not be described again here.
Step 2: a standard curve function is determined.
This step is similar to the step of determining the standard curve function in comparative example 1, and will not be described again here.
The absorbance of the standard solutions of different concentrations measured in this step can be seen in table 6.
TABLE 6 absorbance of standard solutions of different concentrations and their concentrations
| Standard solution concentration (mg/L) | 0 | 25 | 50 | 85 | 100 |
| Absorbance (A) | 0 | 0.196 | 0.0.335 | 0.601 | 0.672 |
From the data in table 6, the standard curve function is obtained as: x= (y-0.0096)/0.0068, where R 2 = 0.9967.
Step3 is the same as step3 in comparative example 1, and will not be described again here.
Step 4: the absorbance of the spectrophotometer was adjusted by distilled water at a wavelength of 590nm, and then the concentration of the trench water sample was measured to be 1.47mg/L and the concentration of the solution obtained in step 3 was measured to be 6.59mg/L, respectively.
Step 5: the concentration of the polymer in the solution to be tested was (6.59-1.47) mg/L=5.12 mg/L.
The total time for determining the polymer concentration by the above procedure was 113min.
In summary, the method for determining the concentration of the polymer provided by the embodiment of the application has short time consumption and high detection efficiency of the polymer.
The foregoing description is only for the convenience of those skilled in the art to understand the technical solution of the present application, and is not intended to limit the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application should be included in the protection scope of the present application.
Claims (5)
1. A method for detecting a concentration of a polymer, the method comprising:
obtaining a first reference solution with a first mass and obtaining a first to-be-tested solution with the first mass from a target oil well, wherein the first reference solution comprises a solvent, and the first to-be-tested solution comprises the solvent and a polymer containing carboxyl;
Adding hydrochloric acid into the first reference solution, regulating the pH value of the hydrogen ion concentration index of the first reference solution to a preset pH value through the hydrochloric acid to obtain a second reference solution, adding the hydrochloric acid into the first solution to be tested, and regulating the pH value of the first solution to the preset pH value through the hydrochloric acid to obtain a second solution to be tested;
determining to consume a second mass of the hydrochloric acid when the pH of the first solution to be tested is adjusted to the preset pH;
Adding a metal ion cross-linking agent solution into the second solution to be tested according to the volume ratio of 1:1 to obtain a third solution to be tested, wherein the metal ion cross-linking agent solution is used for carrying out cross-linking reaction with a polymer in the second solution to be tested;
Measuring a first absorbance of the third solution to be measured and a second absorbance of the second reference solution at a first wavelength, respectively, wherein the second absorbance of the second reference solution is used as a reference, and the influence of the solvent on the measurement of the absorbance of the polymer is removed;
determining a first concentration of a polymer in the first solution to be tested according to the first absorbance, the second absorbance, a pre-acquired standard curve function of the polymer, the first mass and the second mass, wherein the standard curve function is used for reflecting the relation between the concentration of the polymer and the absorbance;
preparing a plurality of first standard solutions of polymers with different concentrations;
Adding the hydrochloric acid into the first standard solution with each concentration, and adjusting the pH value of the first standard solution with each concentration to the preset pH value through the hydrochloric acid to obtain a second standard solution with a plurality of concentrations;
Adding the metal ion cross-linking agent solution into the second standard solutions according to the volume ratio of 1:1 to obtain a plurality of third standard solutions;
measuring, by a spectrophotometer, a third absorbance of the plurality of third standard solutions at the first wavelength;
obtaining a second absorbance of the second reference solution;
obtaining the standard curve function through linear fitting according to the second absorbance, the third absorbance of each third standard solution and the corresponding concentration;
Wherein said determining a first concentration of polymer in said first solution to be tested based on said first absorbance, said second absorbance, a pre-obtained standard curve function for said polymer, said first mass and said second mass comprises: determining a correction coefficient according to the first quality and the second quality; determining a second concentration of the polymer based on the first absorbance, the second absorbance, and the standard curve function; taking the product of the correction coefficient and the second concentration of the polymer as a first concentration of the polymer in the first solution to be tested;
Said determining a correction factor based on said first mass and said second mass, comprising: determining the sum of the first mass and the second mass to obtain a third mass; determining a ratio of the third mass to the first mass, and taking the ratio as the correction coefficient;
Said determining a second concentration of said polymer based on said first absorbance, said second absorbance, and said standard curve function, comprising: determining a target absorbance from the first absorbance and the second absorbance in response to the first absorbance being less than 1; substituting the target absorbance into the standard curve function to obtain a target concentration corresponding to the target absorbance, and taking the target concentration as a second concentration of the polymer; in response to the first absorbance not less than 1, diluting the first solution to be tested to obtain a fourth solution to be tested, taking the fourth solution to be tested as the first solution to be tested, executing the step of adding the hydrochloric acid into the first solution to be tested, and adjusting the pH value of the first solution to be tested to the preset pH value through the hydrochloric acid to obtain a second solution to be tested until the first absorbance is less than 1; determining the target absorbance according to the first absorbance and the second absorbance; substituting the target absorbance into the standard curve function to obtain a target concentration corresponding to the target absorbance; determining the dilution factor of diluting the first solution to be tested; taking the product of the target concentration and the dilution multiple as the second concentration;
the determining the target absorbance according to the first absorbance and the second absorbance comprises the following steps: determining a difference between the first absorbance and the second absorbance; and taking the difference value as the target absorbance.
2. The method of claim 1, wherein determining that the second mass of hydrochloric acid is consumed when the pH of the first solution to be tested is adjusted to the preset pH comprises:
Determining the sum of the mass of the container containing the hydrochloric acid and the mass of the hydrochloric acid before adjusting the pH value of the first solution to be tested to obtain a fourth mass;
determining the sum of the masses of the container and the residual hydrochloric acid in the container when the pH value of the first solution to be tested is regulated to the preset pH value, and obtaining a fifth mass;
taking the difference between the fourth mass and the fifth mass as a second mass consuming the hydrochloric acid.
3. The method of claim 1, wherein the polymer is polyacrylic acid.
4. The method of claim 1, wherein the metal ions in the metal ion crosslinker solution are zirconium ions, aluminum ions, chromium ions, or titanium ions.
5. The method of claim 4, wherein the metal ion crosslinking agent is zirconium oxychloride, aluminum citrate, chromium nitrate, or butyl titanate.
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|---|---|---|---|---|
| JP2005332736A (en) * | 2004-05-21 | 2005-12-02 | Konica Minolta Holdings Inc | Fuel cell device, and portable information equipment |
| CN104458620A (en) * | 2014-12-15 | 2015-03-25 | 中国海洋石油总公司 | Method for detecting concentration of polymer for oil displacement |
| CN105588809A (en) * | 2015-12-15 | 2016-05-18 | 新疆科力新技术发展股份有限公司 | Method for measuring concentration of polyacrylamide in oil field polymer-flooding produced liquid |
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Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2005332736A (en) * | 2004-05-21 | 2005-12-02 | Konica Minolta Holdings Inc | Fuel cell device, and portable information equipment |
| CN104458620A (en) * | 2014-12-15 | 2015-03-25 | 中国海洋石油总公司 | Method for detecting concentration of polymer for oil displacement |
| CN105588809A (en) * | 2015-12-15 | 2016-05-18 | 新疆科力新技术发展股份有限公司 | Method for measuring concentration of polyacrylamide in oil field polymer-flooding produced liquid |
Non-Patent Citations (1)
| Title |
|---|
| 浊度法检测聚丙烯酰胺浓度的研究;李学军等;油气田地面工程;19920629;第11卷(第03期);第41-44页 * |
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