Method for detecting content of polymer in water-based polymer-containing drilling waste liquid

Abstract

The invention discloses a method for detecting the content of polymers in water-based polymer-containing drilling waste liquid, and relates to the technical field of oil and gas field drilling environmental protection. Polymers in drilling fluid waste are extracted, an extracted polymer solution is further prepared, and an absorbance-concentration change curve of the polymer solution is drawn; the content of the polymer in the diluted polymer-containing drilling fluid waste is determined through a colorimetric absorbance method, and then the actual content of the polymer in the polymer-containing drilling fluid waste is calculated through the dilution ratio. According to the method, the step of purifying the polymer once does not need to be repeated for each sample, and the polymer for drawing the standard curve is closer to the complex polymer added in the actual drilling fluid and is more representative. Therefore, for batch waste drilling fluid of the same system type, the detection time is shorter, and the data accuracy is high.

Description

Technical Field

[0001] The present invention relates to the technical field of environmental protection in oil and gas field drilling, and particularly relates to a method for detecting the polymer content in water-based polymer-containing drilling waste liquid. Background Art

[0002] During the drilling construction process, the generation amount of waste mud is relatively large. Each well produces approximately hundreds to thousands of cubic meters of waste mud, which is one of the main pollution sources in the oil and gas industry. The waste mud contains treatment agents such as polyacrylamide and amide group-containing multi-component copolymers. These treatment agents form a stable colloidal suspension system with suspended solids, organic pollutants, and clay, and their content is directly related to the selection of subsequent treatment processes for waste mud and the treatment difficulty.

[0003] At present, the methods for treating waste mud include chemical demulsification-solid-liquid separation method, component recovery and recycling method, chemical solidification treatment method, biological treatment method, etc. Among them, the chemical demulsification-solid-liquid separation method is widely used at the drilling construction site because of its simple construction and simple equipment required. The principle of the chemical demulsification-solid-liquid separation method is to add various inorganic and organic chemical flocculants to the waste mud to neutralize the charge on the surface of solid particles, destroy their surface structure, reduce the electrostatic attraction between solid-phase particles, make the solid-phase particles flocculate and settle, and then use a plate and frame filter press to achieve solid-liquid separation. Removing the polymer in the waste mud can increase the treatment efficiency of solid-liquid separation of the waste mud, make the dosage of the added medicine accurately quantified, and an accurate polymer detection method is the standard for testing the polymer removal effect. Therefore, the premise of removing the polymer is to have an accurate and rapid polymer detection method.

[0004] At the present stage, the polymer detection methods include gel chromatography method, dialysis film drying method, starch-cadmium iodide method, turbidity method, fluorescence spectrophotometry, viscosity method, precipitation method, etc. Among these methods, except for the precipitation method, they are all affected by the change of the hydrolysis degree of the polymer; the precipitation method is affected by the polymer recovery rate and impurities such as salts and surfactants. Therefore, these methods cannot accurately measure the concentration of the polymer in the drilling waste mud and can no longer meet the needs of oil and gas field exploitation. It is necessary to study a new polymer detection method, which can not only speed up the polymer detection speed and improve the detection efficiency, but also remove the measurement error caused by different polymer structures in the original optical methods, ensure the accuracy of the measurement results, save treatment agents for the subsequent treatment of waste mud, and at the same time provide support for maintaining the stability of the drilling fluid system during the drilling process. Summary of the Invention

[0005] The object of the present invention is to provide a method for detecting the polymer content in water-based polymer-containing drilling waste liquid. This method is simple to operate, can accurately detect the polymer content in drilling fluid waste within a short time, and reduces the influence of human error on the experimental results. At the same time, the instrument and equipment used in this method are simple and easy to obtain, improving the timeliness of the polymer detection results in drilling fluid waste.

[0006] To achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a method for detecting the polymer content in water-based polymer-containing drilling waste liquid, and the method includes:

[0008] Step S1: Collect the well-stirred water-based polymer-containing drilling waste liquid, filter to remove impurities, and obtain a polymer-containing filtrate;

[0009] Step S2: Put the filtrate after removing impurities into a semi-permeable membrane bag, remove small molecule impurities in the filtrate, measure the conductivity of the filtrate, and take out the filtrate;

[0010] Step S3: Rotate and evaporate the filtrate to remove water and obtain a concentrated solution;

[0011] Step S4: Add sufficient ethanol to the concentrated solution to dissolve macromolecular substances, while precipitating polymers, filter the concentrated solution, dry the solid phase filtered out to obtain purified polymers;

[0012] Step S5: Use distilled water to prepare a standard solution of the purified polymer, prepare blue starch-iodine complexes respectively and then conduct absorbance tests, and draw a standard curve of the absorbance-concentration relationship;

[0013] Step S6: Dilute the sample of the water-based polymer-containing drilling waste liquid to be measured so that the polymer concentration contained therein is within the detection concentration range of the standard curve. Take the diluted water-based polymer-containing drilling waste liquid to be measured, prepare a blue starch-iodine complex and then measure its absorbance with a UV spectrophotometer, and calculate the polymer concentration in the water-based polymer-containing drilling waste liquid sample through the standard curve. The actual polymer concentration in the sample is obtained by multiplying this concentration by the dilution factor.

[0014] Further, in step S1, the preparation method of the water-based polymer-containing drilling waste liquid is as follows: Add 2 L of distilled water at 100 °C into a container, sequentially add 80 g of bentonite and 2 g of a hydrophobically associating polymer, and pour it into a rotary slurry mixer and stir for 30 min.

[0015] Further, in step S1, the conditions for filtering the waste liquid include: a negative pressure of -0.1 MPa and a single-layer filter membrane with a pore size of 40 - 50 μm.

[0016] Further, in step S1, the obtained polymer-containing filtrate is required to be not less than 50 mL.

[0017] Further, in step S2, the conductivity of the filtrate is required to be less than 50 μs / cm.

[0018] Further, in step S3, the conditions for rotary evaporation of the filtrate include: a negative pressure of -0.1 MPa and a temperature of 50 - 80 °C.

[0019] Further, in step S34, the drying conditions include: a temperature of 105 - 110 °C and a time of 2 - 3 h.

[0020] Further, in step S5, the polymer is formulated into a standard solution with a concentration of 0 - 50 mg / L.

[0021] Further, in step S5, the polymer is formulated into standard solutions with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L.

[0022] Further, in step S6, the preparation method of the blue starch-iodine complex is as follows: Take the polymer standard solution in a volumetric flask, add sodium acetate buffer solution and distilled water, mix and then add saturated bromine water for reaction, continue to add sodium formate solution for reaction, continue to add starch-cadmium iodide reagent, dilute to the scale with distilled water, shake well and let stand, and then measure the absorbance at a wavelength of 590 nm with an ultraviolet spectrophotometer.

[0023] Further, in step S6, the preparation method of the blue starch-iodine complex is as follows: Take 2 mL of the polymer standard solution in a 50 mL volumetric flask, add 5 mL of sodium acetate buffer solution with a pH of 5.0 and 20 mL of distilled water, mix and then add 1 mL of saturated bromine water for reaction for 10 min, continue to add 5 mL of 1% sodium formate solution for reaction for 5 min, continue to add 5 mL of starch-cadmium iodide reagent, dilute to the scale with distilled water, shake well and let stand for 10 min, and then measure the absorbance at a wavelength of 590 nm with an ultraviolet spectrophotometer.

[0024] Further, the preparation method of the sodium acetate buffer solution is as follows: Dissolve 25 g of sodium acetate trihydrate in 800 mL of distilled water, add 0.5 g of aluminum sulfate hydrate, adjust the pH value to 5.0 with acetic acid, and finally dilute to 1000 mL.

[0025] Further, the preparation method of the starch-cadmium iodide reagent is as follows: Dissolve cadmium iodide in distilled water, heat to boiling, dilute, add soluble starch, stir and boil, dissolve and then filter with filter paper, and finally dilute.

[0026] Further, the preparation method of the starch-cadmium iodide reagent is as follows: Dissolve 11 g of cadmium iodide in 400 mL of distilled water, heat to boiling for 10 min, dilute to approximately 800 mL, add 2.5 g of soluble starch, stir and boil for 5 min. After dissolution, filter with filter paper, and finally dilute to 1000 mL.

[0027] Further, the concentration of the diluted water-based polymer-containing drilling waste liquid sample to be measured is 10 - 50 mg / L.

[0028] The technical effects and advantages of the present invention are as follows:

[0029] 1. The present invention combines the advantages of the dialysis film drying method and the starch-cadmium iodide method. In the pretreatment stage, by extracting the polymer from the drilling fluid waste, the polymer is completely extracted and has high purity. Then, further prepare the polymer solution after extraction and draw the absorbance-concentration change curve of the polymer solution. Only need to dilute the test solution to the concentration range of the standard curve, and then the measurement can be carried out quickly. Specifically, determine the polymer content in the diluted polymer-containing drilling fluid waste by the colorimetric absorbance method, and then calculate the actual polymer content in the polymer-containing drilling fluid waste through the dilution multiple. The instrument and equipment used in the present invention are simple and easy to obtain. When facing a large number and multiple batches of test substances, the detection time is short, and it has the advantages of fast detection speed and high detection accuracy.

[0030] 2. The detection method of the present invention mainly relies on preparing polymer solutions with different concentrations by using the purified polymer. After drawing the standard curve, only need to dilute the test solution to the concentration range of the standard curve, and then the polymer concentration can be measured. Compared with the existing methods, there is no need to repeat the step of purifying the polymer for each sample, and the polymer used for drawing the standard curve is also closer to the complex polymer added in the actual drilling fluid, which is more representative. Therefore, for a batch of waste drilling fluids of the same system type, the detection time is shorter and the data accuracy is high.

[0031] Other features and advantages of the present invention will be described in the following specification, and part of them will become obvious from the specification or be understood by implementing the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the structures pointed out in the specification, claims and drawings. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0033] Figure 1This is the standard curve graph of the absorbance-concentration relationship of the present invention. Detailed implementation manners

[0034] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0035] To solve the deficiencies of the prior art, the present invention discloses a method for detecting the polymer content in water-based polymer-containing drilling waste liquid. The method includes the following steps:

[0036] Step S1: Collect the uniformly stirred water-based polymer-containing drilling waste liquid, and pass it through a 40-50 μm single-layer filter membrane under a negative pressure of -0.1 MPa to remove impurities, and obtain no less than 50 mL of filtrate containing polymers.

[0037] In step S1 of the present invention, the -0.1 MPa negative pressure is the maximum vacuum degree that can be achieved by laboratory vacuum filtration, which can accelerate the polymer extraction process; when the pore size of the filter membrane is less than 40 μm, some polymer macromolecules cannot pass through the filter membrane, resulting in incomplete extraction; when the pore size of the filter membrane is greater than 50 μm, fine impurity particles are likely to pass through the filter membrane and be collected, resulting in low polymer purity. Therefore, a 40-50 μm single-layer filter membrane is selected.

[0038] Step S2: Put the filtrate after removing impurities into a semi-permeable membrane bag, tie the bag mouth and immerse it in distilled water. Utilize the concentration difference between the distilled water and the substances in the filtrate to further remove inorganic salts, small molecule organic substances, etc. in the filtrate. The distilled water is changed every 24 hours. When the measured conductivity of the filtrate is less than 50 μs / cm, the filtrate can be taken out.

[0039] Step S3: Rotate and evaporate the filtrate to remove water under a negative pressure of -0.1 MPa and a temperature of 50-80 °C to obtain a concentrated solution.

[0040] In step S3 of the present invention, in the rotary evaporation stage, at a temperature of 50-80 °C, water can be effectively removed and the polymer can be concentrated, and the polymer molecular chain will not be broken into short-chain polymers due to too high temperature, which affects the measurement result.

[0041] Step S4: Add sufficient ethanol to the concentrated solution to dissolve macromolecular substances such as viscosifiers, fluid loss agents, and lubricants, and at the same time precipitate the polymer. Filter the concentrated solution with a 20 μm pore size filter membrane, and dry the filtered solid phase at 105 °C for 2-3 h to obtain the purified polymer.

[0042] In step S4 of the present invention, ethanol can dissolve other macromolecular substances except the depolymerized polymer, reducing the dissolution loss of the polymer during the washing of the polymer micelles. Moreover, ethanol is volatile and is more conducive to rapid drying.

[0043] Step S5: Prepare standard solutions of the purified polymer with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L using distilled water. After preparing blue starch-iodine complexes respectively, perform absorbance tests and plot the standard curve of the absorbance-concentration relationship (as Figure 1 ).

[0044] In step S5 of the present invention, the method for preparing the blue starch-iodine complex is as follows: Take 2 mL of the polymer standard solution in a 50 mL volumetric flask, add 5 mL of sodium acetate buffer solution with a pH of 5.0 and 20 mL of distilled water. After mixing, add 1 mL of saturated bromine water and react for 10 min. Then continue to add 5 mL of 1% sodium formate solution and react for 5 min. Then continue to add 5 mL of starch-cadmium iodide reagent, dilute to the scale with distilled water, shake well and let stand for 10 min, and then measure the absorbance at a wavelength of 590 nm using an ultraviolet spectrophotometer.

[0045] Further, the method for preparing the sodium acetate buffer solution is as follows: Dissolve 25 g of sodium acetate trihydrate in 800 mL of distilled water, add 0.5 g of aluminum sulfate hydrate, adjust the pH value to 5.0 with acetic acid, and finally dilute to 1000 mL.

[0046] Further, the method for preparing the starch-cadmium iodide reagent is as follows: Dissolve 11 g of cadmium iodide in 400 mL of distilled water, heat to boiling for 10 min, dilute to about 800 mL, add 2.5 g of soluble starch, stir and boil for 5 min. After dissolution, filter with filter paper, and finally dilute to 1000 mL.

[0047] Step S6: Dilute the sample of the poly-containing drilling waste liquid to be measured by a certain multiple so that the polymer concentration contained therein is within the detection concentration range of the standard curve. Take 2 mL of the diluted poly-containing drilling waste liquid to be measured, prepare a blue starch-iodine complex, and then measure its absorbance using an ultraviolet spectrophotometer. Calculate the polymer concentration in the poly-containing drilling waste liquid sample through the standard curve, and multiply this concentration by the dilution multiple to obtain the actual polymer concentration in the sample.

[0048] Example 1:

[0049] The present invention provides a method for detecting the polymer content in water-based poly-containing drilling waste liquid in Example 1. The method is carried out according to the following steps:

[0050] Step S1: Pass the water-based polymer-containing drilling fluid with a polymer concentration of 1000 mg / L through a 40-μm single-layer filter membrane under a negative pressure of -0.1 MPa, and collect no less than 50 mL of the polymer-containing filtrate.

[0051] Step S2: Put the collected filtrate into a semipermeable membrane bag, tie the bag mouth and immerse it in distilled water. Replace the distilled water every 24 hours. When the measured conductivity of the filtrate is less than 50 μs / cm, take out the filtrate.

[0052] Step S3: Rotate and evaporate the filtrate to remove water under a negative pressure of -0.1 MPa and a temperature of 80 °C to obtain a concentrated solution.

[0053] Step S4: Add sufficient ethanol to the concentrated solution, filter the concentrated solution with a 20-μm pore size filter membrane, dry the filtered solid phase at 105 °C for 2 h to obtain the purified polymer.

[0054] Step S5: Use distilled water to prepare standard solutions with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L of the purified polymer. Prepare blue starch-iodine complexes respectively and then conduct absorbance tests to plot the standard curve of the absorbance-concentration relationship.

[0055] Step S6: Dilute the water-based polymer-containing drilling fluid with a polymer concentration of 1000 mg / L by 25 times. Take 2 mL of the diluted polymer-containing drilling waste liquid to be measured, prepare a blue starch-iodine complex and then measure its absorbance with a UV spectrophotometer. Calculate the polymer concentration in the polymer-containing drilling waste liquid sample through the standard curve, and multiply this concentration by the dilution factor to obtain the actual polymer concentration in the sample.

[0056] In Example 1 of the present invention, the preparation method of the water-based polymer-containing drilling fluid with a polymer concentration of 1000 mg / L is as follows: Add 2 L of distilled water at 100 °C into a container, sequentially add 80 g of bentonite and 2 g of a hydrophobic associative polymer, and pour it into a rotary slurry mixer and stir for 30 min. Examples 2-3 are the same as Example 1.

[0057] Example 2:

[0058] The present invention provides a method for detecting the polymer content in water-based polymer-containing drilling waste liquid in Example 2. The method is carried out according to the following steps:

[0059] Step S1: Pass the water-based polymer-containing drilling fluid with a polymer concentration of 1000 mg / L through a 50-μm single-layer filter membrane under a negative pressure of -0.1 MPa, and collect no less than 50 mL of the polymer-containing filtrate.

[0060] Step S2: Put the collected filtrate into a semipermeable membrane bag, tie the bag mouth and immerse it in distilled water. Replace the distilled water every 24 hours. When the measured conductivity of the filtrate is less than 50 μs / cm, take out the filtrate.

[0061] Step S3: Rotate and evaporate the filtrate to remove water at a negative pressure of -0.1 MPa and a temperature of 60 °C to obtain a concentrated solution.

[0062] Step S4: Add sufficient ethanol to the concentrated solution, filter the concentrated solution with a filter membrane with a pore size of 20 μm, dry the filtered solid phase at 105 °C for 2.5 h to obtain the purified polymer.

[0063] Step S5: Use distilled water to prepare standard solutions with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L of the purified polymer. After preparing blue starch-iodine complexes respectively, perform absorbance tests and draw a standard curve of the absorbance-concentration relationship.

[0064] Step S6: Dilute the water-based polymer-containing drilling fluid with a polymer concentration of 1000 mg / L by 40 times. Take 2 mL of the diluted polymer-containing drilling waste liquid to be measured. After preparing a blue starch-iodine complex, measure its absorbance with a UV spectrophotometer. Calculate the polymer concentration in the polymer-containing drilling waste liquid sample through the standard curve, and multiply this concentration by the dilution factor to obtain the actual polymer concentration in the sample.

[0065] Example 3:

[0066] Example 3 of the present invention provides a method for detecting the polymer content in water-based polymer-containing drilling waste liquid. The method is carried out according to the following steps:

[0067] Step S1: Pass the water-based polymer-containing drilling fluid with a polymer concentration of 1000 mg / L through a 50-μm single-layer filter membrane under a negative pressure of -0.1 MPa, and collect no less than 50 mL of the filtrate containing the polymer.

[0068] Step S2: Put the collected filtrate into a semi-permeable membrane bag, tie the bag mouth and immerse it in distilled water. Replace the distilled water every 24 hours. When the measured conductivity of the filtrate is less than 50 μs / cm, take out the filtrate.

[0069] Step S3: Rotate and evaporate the filtrate to remove water at a negative pressure of -0.1 MPa and a temperature of 50 °C to obtain a concentrated solution.

[0070] Step S4: Add sufficient ethanol to the concentrated solution, filter the concentrated solution with a filter membrane with a pore size of 20 μm, dry the filtered solid phase at 105 °C for 3 h to obtain the purified polymer.

[0071] Step S5: Use distilled water to prepare standard solutions with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L of the purified polymer. After preparing blue starch-iodine complexes respectively, perform absorbance tests and draw a standard curve of the absorbance-concentration relationship.

[0072] Step S6: Dilute the water-based polymer-containing drilling fluid with a polymer concentration of 1000 mg / L by 50 times. Take 2 mL of the diluted polymer-containing drilling waste liquid to be tested. After preparing the blue starch-iodine complex, measure its absorbance with a UV spectrophotometer. Calculate the polymer concentration in the polymer-containing drilling waste liquid sample through the standard curve, and multiply this concentration by the dilution factor to obtain the actual polymer concentration in the sample.

[0073] Test Example:

[0074] Example 1, Example 2, and Example 3 respectively carried out repeated tests on drilling fluids with polymer concentrations of 40 mg / L, 25 mg / L, and 20 mg / L. At the same time, comparative analysis was carried out with the starch-cadmium iodide method and the dialysis membrane drying method in comparison with Examples 1-3. The experimental results are shown in Table 1.

[0075] Table 1 Comparison of the results of the examples and other detection methods

[0076]

[0077] As can be seen from Table 1, compared with the other two detection methods, the method of the present invention has a detection mean closer to the true value, a smaller relative standard deviation, and high accuracy.

[0078] Finally, it should be noted that the above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A method for detecting the polymer content in water-based polymer-containing drilling waste liquid, characterized in that, The method includes the following steps: Step S1: Collect the well-stirred water-based polymer-containing drilling waste liquid, filter to remove impurities, and obtain a polymer-containing filtrate. Step S2: Put the filtrate after removing impurities into a semi-permeable membrane bag, remove small-molecule impurities in the filtrate, measure the conductivity of the filtrate, and take out the filtrate. Step S3: Rotate-evaporate the filtrate to remove water and obtain a concentrated solution. Step S4: Add sufficient ethanol to the concentrated solution to dissolve macromolecular substances, while precipitating polymers. Filter the concentrated solution, filter out the solid phase and dry it to obtain purified polymers. Step S5: Use distilled water to prepare a standard solution of the purified polymer. Prepare blue starch-iodine complexes respectively and then conduct absorbance tests, and draw a standard curve of the absorbance-concentration relationship. Step S6: Dilute the sample of the water-based polymer-containing drilling waste liquid to be measured so that the polymer concentration contained therein is within the detection concentration range of the standard curve. Take the diluted polymer-containing drilling waste liquid to be measured, prepare a blue starch-iodine complex and then measure its absorbance with a UV spectrophotometer. Calculate the polymer concentration in the polymer-containing drilling waste liquid sample through the standard curve, and multiply this concentration by the dilution factor to obtain the actual polymer concentration in the sample.

2. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S1, the preparation method of the water-based polymer-containing drilling waste liquid is as follows: Add 2 L of distilled water at 100 °C into a container, sequentially add 80 g of bentonite and 2 g of a hydrophobically associating polymer, and pour them into a rotary slurry mixer and stir for 30 min.

3. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S1, the conditions for filtering the waste liquid include: a negative pressure of -0.1 MPa and a single-layer filter membrane with a pore size of 40 - 50 μm.

4. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S1, the obtained polymer-containing filtrate is required to be not less than 50 mL.

5. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S2, the conductivity of the filtrate is required to be less than 50 μs / cm.

6. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S3, the conditions for rotating-evaporating the filtrate include: a negative pressure of -0.1 MPa and a temperature of 50 - 80 °C.

7. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S34, the drying conditions include: a temperature of 105 - 110 °C and a time of 2 - 3 h.

8. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S5, prepare a standard solution of the polymer with a concentration of 0 - 50 mg / L.

9. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 8, characterized in that, In step S5, prepare standard solutions of the polymer with concentrations of 10 mg / L, 20 mg / L, 30 mg / L, 40 mg / L, and 50 mg / L.

10. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, In step S6, the preparation method of the blue starch-iodine complex is as follows: Take the polymer standard solution in a volumetric flask, add sodium acetate buffer solution and distilled water. After mixing, add saturated bromine water to react, then continue to add formate solution to react, and then continue to add starch-cadmium iodide reagent, dilute to the scale with distilled water, shake well and let it stand, and then measure the absorbance with a UV spectrophotometer at a wavelength of 590 nm.

11. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 10, characterized in that, In step S6, the preparation method of the blue starch-iodine complex is as follows: Take 2 mL of the polymer standard solution in a 50 mL volumetric flask, add 5 mL of sodium acetate buffer solution with a pH of 5.0 and 20 mL of distilled water. After mixing, add 1 mL of saturated bromine water and react for 10 min, then continue to add 5 mL of 1% formate solution and react for 5 min, then continue to add 5 mL of starch-cadmium iodide reagent, dilute to the scale with distilled water, shake well and let it stand for 10 min, and then measure the absorbance with a UV spectrophotometer at a wavelength of 590 nm.

12. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 10 or 11, characterized in that, The preparation method of the sodium acetate buffer solution is as follows: Dissolve 25 g of sodium acetate trihydrate in 800 mL of distilled water, add 0.5 g of aluminum sulfate hydrate, adjust the pH value to 5.0 with acetic acid, and finally dilute to 1000 mL.

13. The method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 10, characterized in that, The preparation method of the starch-cadmium iodide reagent is as follows: Dissolve cadmium iodide in distilled water, heat to boiling, dilute, add soluble starch, stir and boil, filter with filter paper after dissolution, and finally dilute.

14. A method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 13, characterized in that, The preparation method of the starch-cadmium iodide reagent is as follows: Dissolve 11 g of cadmium iodide in 400 mL of distilled water, heat to boiling for 10 min, dilute to about 800 mL, add 2.5 g of soluble starch, stir and boil for 5 min, filter with filter paper after dissolution, and finally dilute to 1000 mL.

15. A method for detecting the polymer content in water-based polymer-containing drilling waste liquid according to claim 1, characterized in that, The concentration of the diluted water-based polymer-containing drilling waste liquid sample to be measured is 10 - 50 mg / L.

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