Temperature-resistant salt-resistant hydrophobic association polyacrylamide and preparation method thereof

Abstract

The invention belongs to the technical field of polymer synthesis, and relates to temperature-resistant and salt-resistant hydrophobic association polyacrylamide and a preparation method thereof. The preparation method comprises the following steps: preparing a polymerizable hydrophobic monomer through esterification reaction of naphthol polyoxyethylene ether and acryloyl chloride; the monomer is polymerized with acrylamide and other functional monomers to obtain the hydrophobic associated polyacrylamide with higher temperature resistance and salt resistance. The hydrophobically associated polyacrylamide shows relatively high temperature resistance and salt resistance, and can solve the problems of poor temperature resistance and salt resistance of partially hydrolyzed polyacrylamide commonly used in oil fields at present.

Description

Technical Field

[0001] This invention belongs to the field of polymer synthesis technology and relates to a temperature-resistant and salt-resistant hydrophobic associative polyacrylamide and its preparation method. Background Technology

[0002] As a non-renewable resource, oil is a cornerstone energy source and a key chemical raw material for global economic development and social operation. Therefore, improving oil recovery has become a global technological challenge. Tertiary oil recovery utilizes complex physicochemical techniques to alter the physicochemical properties of reservoirs and fluids, thereby increasing recovery rates. Polymer flooding, in particular, is one of the most mature and effective strategies in tertiary oil recovery technology.

[0003] Polymer flooding involves adding water-soluble polymers to the injected water to significantly increase the viscosity of the driving phase and reduce the permeability of the aqueous phase in porous media. This improves the mobility ratio, expands the macroscopic and microscopic swept volume, and effectively displaces previously unusable residual oil. Currently, partially hydrolyzed polyacrylamide is the most widely used polymer. However, as the focus of global oil and gas exploration and development gradually shifts to harsh reservoir conditions, especially high-temperature and high-salinity reservoirs, traditional partially hydrolyzed polyacrylamide is increasingly unable to meet the requirements. In high-temperature and high-salinity reservoir environments, partially hydrolyzed polyacrylamide is prone to thermal degradation and salt sensitivity, severely limiting its application in high-temperature and high-salinity reservoirs, which account for more than half of the global total. Therefore, there is an urgent need to develop a new generation of high-performance oil displacement polymer materials to overcome this technological barrier.

[0004] To address the poor temperature and salt resistance of partially hydrolyzed polyacrylamide, existing technologies typically employ the introduction of temperature and salt resistant functional monomers into the polyacrylamide molecular chain to improve its temperature and salt resistance. For example, patent CN1814637A discloses a method for preparing temperature and salt resistant polyacrylamide, which introduces three temperature and salt resistant monomers to copolymerize with acrylamide, synthesizing temperature and salt resistant copolymers such as acrylamide / 2-acrylamido-2-methylpropanesulfonic acid / methacrylic acid / dimethyldiallylammonium chloride tetropolymer and acrylamide / 2-acrylamide and 2-methylpropanesulfonic acid / itaconic acid / acryloyloxyethyltrimethylammonium chloride tetropolymer. These polymers do improve the temperature and salt resistance of the product, but they can only meet the requirements under conditions of mineralization below 10000 mg / L and temperature below 65℃, and cannot meet the application requirements under higher temperature and mineralization conditions. Summary of the Invention

[0005] To address the problem of poor temperature and salt resistance of HPAM commonly used in oilfields, this invention provides a method for adding functional monomers that enhance the temperature and salt resistance of the polyacrylamide molecular backbone. The hydrophobic associative polyacrylamide of this invention exhibits strong temperature and salt resistance, with a viscosity retention rate of 75% at 95°C and a viscosity of over 70 mPa·s in a 50,000 mg / L NaCl solution.

[0006] The technical solution adopted by this invention to solve its technical problem is: A temperature-resistant and salt-resistant hydrophobic associative polyacrylamide has the following structural formula: ; Where x = 30000~70000, y = 1000~10000, z = 10000~30000, a = 1000~3000, and x, y, z, and a are all integers.

[0007] Furthermore, the present invention provides a method for preparing the temperature-resistant and salt-resistant hydrophobic associative polyacrylamide, comprising the following steps: (1) Dissolve naphthol polyoxyethylene ether (n) in dichloromethane, add an acid-binding agent, stir the system at low temperature, and when the system temperature drops to 0-10℃, add acryloyl chloride dropwise to the system. The dropwise addition is completed within 30-60 min. After the dropwise addition is completed, react at low temperature for 4-10 h. After the reaction is completed, filter out the white solid salt. Rotate the filtrate at 30-70℃ to obtain the functional monomer naphthol polyoxyethylene ether acrylate (n), where n is 10-30. The mass ratio of acryloyl chloride, naphthol polyoxyethylene ether (n), and acid-binding agent is 1:2:1-1:6:3. (2) Add the temperature-resistant and salt-resistant hydrophobic associative water-soluble copolymer monomer and naphthol polyoxyethylene ether acrylate (n) to deionized water and stir to dissolve. Add the cosolvent and chelating agent in sequence. The cosolvent accounts for 0.1-0.8% of the total monomer mass, and the chelating agent accounts for 0.1-0.5% of the total monomer mass. Adjust the pH of the system to 5-10, add deionized water to make the monomer mass concentration of the system 10-50%, heat the solution to 40-60℃, and purge with high-purity nitrogen for 30-60 min. Then add the initiator at 0.1-0.75% of the total monomer mass. Stop purging nitrogen when the system becomes obviously viscous. After reacting for 4-12 h, take out the elastic polymer block. Granulate the block with a granulator and pulverize it for 40- Vacuum drying at 55℃, followed by pulverization and sieving of the dried product to obtain the finished product; the temperature-resistant and salt-resistant hydrophobic associative water-soluble copolymer monomer is composed of monomer 1 and monomer 2, monomer 3 and monomer 4 in a mass ratio of (1:3:15:40)-(1:20:65:160); wherein monomer 1 is selected from naphthol polyoxyethylene ether acrylate; monomer 2 is selected from any one of methacryloyloxyethyl-N,N-diethylpropanesulfonate, sodium styrene sulfonate, N-vinylpyrrolidone, and 2-acrylamido-2-methylpropanesulfonic acid; monomer 3 is acrylic acid, and monomer 4 is acrylamide.

[0008] Preferably, the acid-binding agent is one or more of triethylamine, anhydrous sodium carbonate, and N,N-diisopropylethylamine.

[0009] Preferably, the acrylate monomer is one or more of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide, acrylic acid, sodium styrene sulfonate, and N-vinylpyrrolidone.

[0010] Preferably, the co-solvent is selected from sodium dodecyl sulfate, alkylphenol polyoxyethylene ether, sodium dodecylbenzene sulfonate, and the chelating agent is one or more of disodium ethylenediaminetetraacetate and sodium citrate.

[0011] Preferably, the pH adjuster is one or more of sodium hydroxide, sodium bicarbonate, ammonia, and glacial acetic acid, with a concentration of 1-30%.

[0012] Preferably, the initiator is azobisisobutyramidine hydrochloride.

[0013] Furthermore, the present invention also provides the application of the temperature-resistant and salt-resistant hydrophobic associative polyacrylamide, which is used for the recovery of oil reservoirs in high-temperature and high-salinity environments.

[0014] The beneficial effects of this invention are reflected in: (1) This invention provides a method for preparing a hydrophobically associating acrylamide copolymer with strong temperature and salt resistance. Based on the properties of the raw materials for synthesizing temperature- and salt-resistant polyacrylamide, functional monomers that can provide temperature and salt resistance are added to design a hydrophobically associating polyacrylamide with strong temperature and salt resistance. It can be used as an oil displacement agent, as well as a thickener for fracturing fluids and a drilling fluid treatment agent.

[0015] (2) The temperature- and salt-resistant functional monomers added to the hydrophobic associative polyacrylamide molecular chain in the present invention can effectively weaken the charge shielding effect of cations in water, inhibit the hydrolysis of amide groups and provide greater steric hindrance, thereby improving the temperature and salt resistance of polyacrylamide. The added naphthol polyoxyethylene ether acrylate can form a "dynamic physical cross-linking network" of polyacrylamide in water through hydrophobic groups, thereby increasing the viscosity of polyacrylamide itself under high temperature and high salt reservoir conditions. Attached Figure Description

[0016] Figure 1 1H NMR spectrum analysis of naphthol polyoxyethylene ether acrylate BMO-12 prepared in Example 1; Figure 2 Fourier transform infrared spectroscopy analysis of naphthol polyoxyethylene ether acrylate BMO-12 prepared in Example 1; Figure 3 Hydrogen nuclear magnetic resonance (HMR) spectrum analysis of the hydrophobically associating polyacrylamide P (AM / AA / AMPS / BMO) prepared in Example 1; Figure 4 Fourier transform infrared spectroscopy analysis of the hydrophobically associating polyacrylamide P (AM / AA / AMPS / BMO) prepared in Example 1; Figure 5 The molecular weight determination of hydrophobic associating polyacrylamide provided by the present invention; Figure 6 Temperature resistance study of the hydrophobic associating polyacrylamide provided for this invention; Figure 7 Salt resistance study of the hydrophobic associating polyacrylamide provided for this invention. Detailed Implementation

[0017] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0018] Example 1: This example provides a temperature-resistant and salt-resistant hydrophobic associative polyacrylamide, the preparation method of which includes the following steps: S1: Dissolve 10 g of naphthol polyoxyethylene ether (12) in 60 g of dichloromethane and place it in a three-necked flask. Add 1.61 g of triethylamine as an acid-binding agent. Stir the system at low temperature until the temperature drops to 0°C. Then, weigh 1.51 g of acryloyl chloride and dissolve it in 15 g of dichloromethane. Add acryloyl chloride dropwise to the naphthol polyoxyethylene ether (12) solution using a syringe. The acryloyl chloride is added over a period of 30 min. After the acryloyl chloride is added, allow the system to react at 0°C for 6 h. After the reaction, filter out the white solid salt. Rotate the filtrate at 50°C to obtain naphthol polyoxyethylene ether acrylate (12), with the following structural formula: .

[0019] S2: Add 0.5 g of 2-acrylamido-2-methylpropanesulfonic acid to a 100 mL beaker, then add 3 g of acrylic acid and 20 g of deionized water. Stir to mix the solution evenly. While stirring, add 20% NaOH solution to adjust the pH of the solution to 7.5. Then weigh 7 g of acrylamide and add it to the beaker. Stir for 5-10 min to dissolve it evenly. Weigh 0.1 g of naphthol polyoxyethylene ether acrylate (12) and add it to the beaker. Stir for 5 min to disperse naphthol polyoxyethylene ether acrylate (12) evenly in the solution. Weigh 0.2 g of sodium dodecyl sulfate and add it to the solution while stirring. After the sodium dodecyl sulfate is completely dissolved, a transparent solution is obtained. Then weigh 0.012 g of disodium ethylenediaminetetraacetate and add it to the solution. After it is completely dissolved, add deionized water to the beaker to make the monomer concentration account for 20% of the total mass of the solution. The solution was poured into a four-necked flask, and a thermometer and condenser were inserted. The flask was placed in a water bath and heated to 45°C. A gas distributor was inserted to purge the solution with nitrogen for 30 minutes to remove oxygen. During this period, 0.021 g of azobisisobutyramidine hydrochloride was dissolved in 4 g of deionized water. After the nitrogen purging was completed, the initiator azobisisobutyramidine hydrochloride solution was added dropwise to the solution. The initiator was added dropwise over 15 minutes. During the addition, the flask was lifted and shaken for 10 seconds every 1 minute to ensure even dispersion of the initiator. Nitrogen purging continued until the solution became noticeably viscous. Nitrogen purging was then stopped, the reactor was sealed, and the reaction was allowed to proceed for 8 hours. The polymer block was then removed, granulated using a granulator, and placed in a vacuum drying oven at 45°C for 18 hours to obtain hydrophobically associating polyacrylamide with a molecular weight of 5.05 × 10⁻⁶. 6 The structural formula is as follows: ; Where x = 30000~70000, y = 1000~10000, z = 10000~30000, a = 1000~3000, and x, y, z, and a are all integers.

[0020] Example 2: This example provides a temperature-resistant and salt-resistant hydrophobic associative polyacrylamide, the preparation method of which includes the following steps: S1: Dissolve 10 g of naphthol polyoxyethylene ether (21) in 60 g of dichloromethane and place it in a three-necked flask. Add 1.01 g of anhydrous sodium carbonate as an acid-binding agent. Stir the system at low temperature until the temperature drops to 2°C. Then weigh 0.86 g of acryloyl chloride and dissolve it in 15 g of dichloromethane. Add acryloyl chloride dropwise to the naphthol polyoxyethylene ether (21) solution using a syringe. The acryloyl chloride dropwise addition time is 30 min. After the acryloyl chloride dropwise addition is completed, react at low temperature for 8 h. After the reaction is completed, filter out the white solid salt. The filtrate is rotary evaporated at 50°C to obtain naphthol polyoxyethylene ether acrylate (21). S2: Add 0.6 g of 2-acrylamido-2-methylpropanesulfonic acid to a 100 mL beaker, then add 2.5 g of acrylic acid and 20 g of deionized water. Stir to mix the solution evenly. While stirring, add 20% NaHCO3 solution to adjust the pH of the solution to 8. Then weigh 7.5 g of acrylamide and add it to the beaker. Stir for 5-10 min to dissolve it evenly. Weigh 0.08 g of naphthol polyoxyethylene ether acrylate (21) and add it to the beaker. Stir for 5 min to disperse naphthol polyoxyethylene ether acrylate (21) evenly in the solution. Weigh 0.15 g of sodium dodecyl sulfate and add it to the solution while stirring. After the sodium dodecyl sulfate is completely dissolved, a transparent solution is obtained. Then weigh about 0.0122 g of disodium ethylenediaminetetraacetate and add it to the solution. After it is completely dissolved, add deionized water to the solution so that the monomer concentration accounts for 22% of the total mass of the solution. The solution was poured into a four-necked flask, and a thermometer and condenser were inserted. The flask was placed in a water bath and heated to 50°C. A gas distributor was inserted to purge the solution with nitrogen for 30 minutes to remove oxygen. During this period, 0.02 g of azobisisobutyramidine hydrochloride was dissolved in 4 g of deionized water. After the nitrogen purging was completed, the initiator azobisisobutyramidine hydrochloride solution was added dropwise to the solution. The initiator was added dropwise over 15 minutes. During the addition, the flask was lifted and shaken for 10 seconds every 1 minute to ensure even dispersion of the initiator. Nitrogen purging continued until the solution became noticeably viscous. Nitrogen purging was then stopped, the reactor was sealed, and the reaction was allowed to proceed for 6 hours. The polymer block was then removed, granulated using a granulator, and placed in a vacuum drying oven at 45°C for 18 hours to obtain hydrophobically associating polyacrylamide with a molecular weight of 5.85 × 10⁻⁶. 6 ; Example 3: This example provides a temperature-resistant and salt-resistant hydrophobic associative polyacrylamide, the preparation method of which includes the following steps: S1: Dissolve 10 g of naphthol polyoxyethylene ether (24) in 60 g of dichloromethane and place it in a three-necked flask. Add 1.04 g of N,N-diisopropylethylamine as an acid-binding agent. Stir the system at low temperature until the temperature drops to 5°C. Then weigh 0.73 g of acryloyl chloride and dissolve it in 15 g of dichloromethane. Add acryloyl chloride dropwise to the naphthol polyoxyethylene ether (24) solution using a syringe. The acryloyl chloride is added over 30 min. After the acryloyl chloride is added, react at low temperature for 10 h. After the reaction is complete, filter out the white solid salt. Rotate the filtrate at 50°C to obtain naphthol polyoxyethylene ether acrylate (24). S2: Add 0.8 g of 2-acrylamido-2-methylpropanesulfonic acid to a 100 mL beaker, then add 3.5 g of acrylic acid and 20 g of deionized water. Stir to mix the solution evenly. While stirring, add 10% ammonia solution to adjust the pH of the solution to about 7. Then weigh 6.5 g of acrylamide and add it to the beaker. Stir for 5-10 min to dissolve it evenly. Weigh 0.15 g of naphthol polyoxyethylene ether acrylate (24) and add it to the beaker. Stir for 5 min to disperse naphthol polyoxyethylene ether acrylate (24) evenly in the solution. Weigh 0.3 g of sodium dodecyl sulfate and add it to the solution while stirring. After the sodium dodecyl sulfate is completely dissolved, a transparent solution is obtained. Then weigh about 0.013 g of disodium ethylenediaminetetraacetate and add it to the solution. After it is completely dissolved, add deionized water to the solution so that the monomer concentration accounts for 25% of the total mass of the solution. The solution was poured into a four-necked flask, and a thermometer and condenser were inserted. The flask was placed in a water bath and heated to 55°C. A gas distributor was inserted to purge the solution with nitrogen for 30 minutes to remove oxygen. During this period, 0.022 g of azobisisobutyramidine hydrochloride was dissolved in 4 g of deionized water. After the nitrogen purging was completed, the initiator azobisisobutyramidine hydrochloride solution was added dropwise to the solution. The initiator was added dropwise over 15 minutes. During the addition, the flask was lifted and shaken for 10 seconds every 1 minute to ensure even dispersion of the initiator. Nitrogen purging continued until the solution became noticeably viscous. Nitrogen purging was then stopped, the reactor was sealed, and the reaction was allowed to proceed for 10 hours. The polymer block was then removed, granulated using a granulator, and placed in a vacuum drying oven at 45°C for 18 hours to obtain hydrophobically associating polyacrylamide with a molecular weight of 6.38 × 10⁻⁶. 6 .

[0021] like Figure 1-2As shown, the target product of Example 1, naphthol polyoxyethylene ether acrylate (12), was subjected to 1H NMR spectroscopy and Fourier transform infrared spectroscopy analysis to confirm that the synthesized product was the target product. The analysis is as follows: the characteristic signal observed at a is attributed to the -(CH2-CH2-O)- group on naphthol polyoxyethylene ether acrylate; the characteristic signal observed at b is attributed to the (=CH2) and (=CH-C) groups on the carbon-carbon double bond; the chemical shift detected at c is determined to be the hydrogen atom on the naphthalene ring; the obvious peak at d is attributed to the -(CH2)- group connected to the naphthalene ring ester group; and the peak at e is attributed to the -(CH2)- group connected to the -(CH2-CH2-O)- group.

[0022] like Figure 3-4 As shown, the target product of Example 1, hydrophobic associating polyacrylamide, was analyzed by 1H NMR spectroscopy and Fourier transform infrared spectroscopy, confirming that the synthesized product was the target product. The analysis is as follows: the characteristic signal observed at position a is attributed to the -(CH2)- group on the main chain of the polyacrylamide molecule; the characteristic signal observed at position b is attributed to the (=CH-C) group on the main chain of the molecule; the chemical shift detected at position c was identified as the -(CH2-CH2-O)- group on the side chain; the obvious peak at position d is attributed to the (-CH3) group on 2-acrylamido-2-methylpropanesulfonic acid.

[0023] Molecular weight determination: The molecular weight of hydrophobic associating polyacrylamide was determined according to national standards (GB / T 12005.1-1989 and GB / T 12005.10-1992).

[0024] Example 4: Molecular weight and performance tests were performed on the temperature-resistant and salt-resistant hydrophobic associating polyacrylamide prepared in the examples of this invention. Temperature resistance test: An aqueous solution containing 0.2 wt% hydrophobic associating polyacrylamide was precisely prepared and tested at a shear rate of 7.34 s⁻¹. -1 Under the given conditions, a rotational viscometer was used to measure the viscosity of the hydrophobic associative polyacrylamide at different temperatures, and the temperature resistance of the polyacrylamide under different temperature conditions was evaluated.

[0025] Salt tolerance test: An aqueous solution containing 0.2 wt% hydrophobically associating polyacrylamide was precisely prepared. The salt concentration was adjusted by adding different masses of NaCl. The salt tolerance was tested at a shear rate of 7.34 s⁻¹. -1 At a temperature of 25℃, the viscosity of the hydrophobically associating polyacrylamide under different NaCl concentrations was measured using a rotational viscometer to evaluate its salt tolerance under different salinity conditions.

[0026] The test results are as follows: (1). Molecular weight determination results are as follows Figure 5As shown: According to the formula [η] in the national standards (GB / T 12005.1-1989 and GB / T12005.10-1992)... M=802[η] 1.25 The molecular weight of the hydrophobically associating polyacrylamide can be calculated to be 5.05 × 10⁻⁶. 6 .

[0027] (2). The results of the temperature resistance test are as follows: Figure 6 As shown, the apparent viscosity of hydrophobic associating polyacrylamide exhibits a regular decreasing trend with increasing temperature. When the temperature reaches 95℃, the apparent viscosity of hydrophobic associating polyacrylamide decreases from 424.2 mPa·s to 318.7 mPa·s, with a viscosity retention rate of 75.1%. These results indicate that hydrophobic associating polyacrylamide has strong temperature resistance.

[0028] (3). Salt resistance test results are as follows Figure 7 As shown, the apparent viscosity of hydrophobically associating polyacrylamide initially increases and then decreases with increasing NaCl concentration. At a NaCl concentration of 3000 mg / L, the hydrophobically associating polyacrylamide exhibits significant salt thickening. When the NaCl concentration exceeds 10000 mg / L, the viscosity gradually decreases. Even at a NaCl concentration of 50000 mg / L, the apparent viscosity of the hydrophobically associating polyacrylamide still exceeds 70 mPa·s. These results indicate that hydrophobically associating polyacrylamide possesses strong salt resistance.

Claims

1. A temperature-resistant and salt-resistant hydrophobic associative polyacrylamide, characterized in that, It has the following structural formula: ； Where x = 30000~70000, y = 1000~10000, z = 10000~30000, a = 1000~3000, and x, y, z, and a are all integers.

2. The preparation method of the temperature-resistant and salt-resistant hydrophobic associative polyacrylamide according to claim 1, characterized in that, Includes the following steps: (1) Dissolve naphthol polyoxyethylene ether (n) in dichloromethane, add an acid-binding agent, stir the system at low temperature, and when the system temperature drops to 0-10℃, add acryloyl chloride dropwise to the system. The dropwise addition is completed within 30-60 min. After the dropwise addition is completed, react at low temperature for 4-10 h. After the reaction is completed, filter out the white solid salt. The filtrate is rotary evaporated at 30-70℃ to obtain the functional monomer naphthol polyoxyethylene ether acrylate (n), where n is 10-30. The mass ratio of acryloyl chloride, naphthol polyoxyethylene ether (n), and acid-binding agent is (1:2:1)-(1:6:3). (2) Add the temperature-resistant and salt-resistant hydrophobic associative water-soluble copolymer monomer and naphthol polyoxyethylene ether acrylate (n) to deionized water and stir to dissolve. Add the cosolvent and chelating agent in sequence. The cosolvent accounts for 0.1-0.8% of the total monomer mass, and the chelating agent accounts for 0.1-0.5% of the total monomer mass. Adjust the pH of the system to 5-10, add deionized water to make the monomer concentration of the system 10-50% by mass, heat the solution to 40-60℃, and purge with high-purity nitrogen for 30-60 min. Then add the initiator at 0.1-0.75% of the total monomer mass. Stop purging nitrogen when the system becomes obviously viscous. After reacting for 4-12 h, take out the elastic polymer block. Granulate the block with a granulator and pulverize it for 40- Vacuum drying at 55℃, followed by pulverization and sieving of the dried product to obtain the finished product; the temperature-resistant and salt-resistant hydrophobic associative water-soluble copolymer monomer is composed of monomer 1 and monomer 2, monomer 3 and monomer 4 in a mass ratio of (1:3:15:40)-(1:20:65:160); wherein monomer 1 is selected from naphthol polyoxyethylene ether acrylate; monomer 2 is selected from any one of methacryloyloxyethyl-N,N-diethylpropanesulfonate, sodium styrene sulfonate, N-vinylpyrrolidone, and 2-acrylamido-2-methylpropanesulfonic acid; monomer 3 is acrylic acid, and monomer 4 is acrylamide.

3. The preparation method according to claim 2, characterized in that: The acid-binding agent is one or more of triethylamine, anhydrous sodium carbonate, and N,N-diisopropylethylamine.

4. The preparation method according to claim 2, characterized in that: The acrylate monomers are one or more of 2-acrylamido-2-methylpropanesulfonic acid, acrylamide, acrylic acid, sodium styrene sulfonate, and N-vinylpyrrolidone.

5. The preparation method according to claim 2, characterized in that: The cosolvent is selected from sodium dodecyl sulfate, alkylphenol polyoxyethylene ether, and sodium dodecylbenzene sulfonate, and the chelating agent is one or more of disodium ethylenediaminetetraacetate and sodium citrate.

6. The preparation method according to claim 2, characterized in that: The pH adjuster is one or more of sodium hydroxide, sodium bicarbonate, ammonia, and glacial acetic acid, with a concentration of 1-30%.

7. The preparation method according to claim 2, characterized in that, The initiator is azobisisobutyramidine hydrochloride.

8. The application of the temperature-resistant and salt-resistant hydrophobic associative polyacrylamide according to claim 1, characterized in that, The polyacrylamide is used for the recovery of oil from high-temperature and high-salinity reservoirs.

Images