High-temperature-resistant polyacrylamide for oil displacement and preparation method thereof
By introducing graft polymerization of functional monomers such as hydroxypropyl methylcellulose, acrylamide, methylallyloxyethylene ether and sodium para-styrene sulfonate into the polymer oil flooding agent, a three-dimensional network structure is formed, which solves the problem of polymer molecular degradation at high temperatures and achieves higher temperature resistance and recovery.
Patent Information
- Application Number
- CN202510448065.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-04-10
- Publication Date
- 2025-07-11
AI Technical Summary
The existing polymer oil flooding agents have severe hydrolysis and molecular degradation at high temperatures, resulting in a decrease in viscosity and unable to effectively improve recovery.
Hydroxypropyl methylcellulose is used as the main chain, and functional monomers such as acrylamide, methylallyloxyethylene ether and sodium styrene sulfonate are grafted polymerization to form a three-dimensional porous network structure, and lignin-based macromolecular chain transfer agent and anionic surfactant are introduced to enhance the intermolecular action force and stability.
It improves the high temperature resistance of the polymer, enhances the apparent viscosity at high temperature, improves the displacement efficiency, and improves the oil recovery rate.
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Abstract
Description
Technical Field
[0001] This application relates to the technical field of polyacrylamide, and particularly relates to a polyacrylamide for high-temperature oil displacement and its preparation method. Background Art
[0002] Oil, as an important non-renewable resource, plays a crucial role in national progress and economic development. Considering the current situation of oil resource exploitation in our country, after primary and secondary oil recovery, a large amount of crude oil still remains in reservoirs with harsh environments. To further improve oil recovery, the tertiary oil recovery technology has been gradually improved, and polymer flooding has been widely used due to its strong practicality and applicability. In the traditional polymer flooding process, polyacrylamide with a linear molecular structure is widely used to improve oil recovery because of its low price and easy preparation. The oil displacement mechanism of the polymer mainly utilizes the viscosity of the water-soluble polyacrylamide molecular chain to improve the mobility ratio of the displacement fluid, enhance the displacement efficiency and swept volume, thereby achieving the purpose of increasing oil recovery.
[0003] However, due to the long cycle of tertiary oil recovery and the high temperature in deep oil wells, polyacrylamide-based oil displacement agents undergo obvious hydrolysis and molecular degradation reactions at high temperatures, and their temperature resistance performance is poor. In reservoirs with high salinity, especially those with high contents of high-valent metal ions, their viscosity will drop significantly, and even precipitation will occur. Therefore, in high-temperature reservoirs, a good oil displacement effect cannot be achieved. Summary of the Invention
[0004] In order to improve the temperature resistance of polyacrylamide, this application provides a polyacrylamide for high-temperature oil displacement and its preparation method.
[0005] In the first aspect, a polyacrylamide for high-temperature oil displacement provided by this application adopts the following technical solution: A polyacrylamide for high-temperature oil displacement comprises the following raw materials in parts by mass: 1.1 - 1.5 parts of hydroxypropyl methylcellulose 18 - 22 parts of functional monomer 0.08 - 0.12 parts of initiator 80 - 100 parts of deionized water The functional monomer includes acrylamide and methallyloxyethyl ether.
[0006] By adopting the above technical solution, using hydroxypropyl methylcellulose as the main chain and acrylamide and methallyloxyethyl ether as functional monomers for graft polymerization, acrylamide and methallyloxyethyl ether are successfully grafted onto the main chain of hydroxypropyl methylcellulose. These two monomers generate a larger steric hindrance between the molecular chains, preventing the aggregation within the molecular chains and forming a three-dimensional porous network structure, and the network structure is regular and compact.
[0007] In addition, both hydroxypropyl methylcellulose and methallyl oxyethylene ether have thermosensitivity. Methallyl oxyethylene ether has a long-chain alkyl structure with hydrophobic properties. Hydroxypropyl methylcellulose and methallyl oxyethylene ether contain many -OH groups, which enable hydrogen bonds to form between polymer molecules, promoting the formation of a three-dimensional network structure of polyacrylamide. As the temperature increases, the hydrophobic interaction between molecular chains enhances, causing polyacrylamide to exhibit a higher apparent viscosity at high temperatures and improving the temperature resistance characteristics of polyacrylamide.
[0008] Moreover, methallyl oxyethylene ether with a long ether chain group enables strong interaction between polymer molecular chains, stretching and growing the molecular chains, which is conducive to the formation of a stable three-dimensional network structure. And the rigid ring structure of the introduced hydroxypropyl methylcellulose can improve the stability of the copolymer molecular chain, effectively enhancing the temperature resistance performance of the polymer.
[0009] Preferably, the functional monomer further includes sodium p-styrenesulfonate.
[0010] By adopting the above technical solution, the rigid benzene ring structure in the sodium p-styrenesulfonate molecule can improve the stability of the polymer molecule, thereby enhancing the temperature resistance performance of the polymer. And the sulfonic acid group can also effectively inhibit the hydrolysis of the polymer at high temperatures, protecting the amide group and thus improving the temperature resistance performance of the polymer.
[0011] Preferably, the mass ratio of acrylamide, methallyl oxyethylene ether, and sodium p-styrenesulfonate is (1.5 - 1.9) : 1 : 0.1.
[0012] By adopting the above technical solution, controlling the mass ratio of acrylamide, methallyl oxyethylene ether, and sodium p-styrenesulfonate within the above range can effectively improve the temperature resistance characteristics of polyacrylamide.
[0013] Preferably, the polyacrylamide further includes 0.04 - 0.14 parts of a lignin-based macromolecular chain transfer agent.
[0014] By adopting the above technical solution, the phenolic hydroxyl group in the lignin-based macromolecular chain transfer agent lignin can act as a hydrogen donor, effectively terminating the growing chain during the chain transfer process and simultaneously generating new free radicals to continue initiating polymerization, forming a controllable chain growth cycle. Due to the relatively large size of the lignin molecule, it has a higher chain transfer efficiency, can provide more active sites, and thus continuously participates in the reaction, prolonging the reaction time while maintaining high activity, and further promoting the contact and reaction of functional monomers in the reaction system.
[0015] And the rigid structure of lignin restricts the movement of polymer chains, reducing chain entanglement, which is thus conducive to the further reaction of functional monomers and promotes the improvement of the temperature resistance characteristics of polyacrylamide.
[0016] Preferably, the preparation method of the lignin-based macromolecular chain transfer agent comprises the following steps: Lignin, an aqueous sodium hydroxide solution, and dimethyl sulfoxide are mixed and stirred evenly. Carbon disulfide is added under an ice-water bath. After the reaction ends, methyl 2-bromobutyrate is added. Then, after the reaction, centrifugal separation is carried out, and the obtained precipitate is washed and dried in sequence to obtain the lignin-based macromolecular chain transfer agent.
[0017] By adopting the above technical solution, the hydroxyl group in lignin reacts with carbon disulfide and methyl 2-bromobutyrate to synthesize the lignin-based macromolecular chain transfer agent. The lignin-based macromolecular chain transfer agent can be efficiently used in the polymerization reaction of acrylamide, promoting the contact and reaction of functional monomers in the reaction system, and prompting the further reaction of functional monomers, thereby promoting the improvement of the temperature resistance characteristics of polyacrylamide.
[0018] Preferably, the mass ratio of the lignin to methyl 2-bromobutyrate is 1:(2.8 - 3.2).
[0019] By adopting the above technical solution, controlling the mass ratio of the lignin to methyl 2-bromobutyrate within the above range can effectively improve the stability of the lignin-based macromolecular chain transfer agent.
[0020] Preferably, 2 - 6 parts of an anionic surfactant are further added to the polyacrylamide.
[0021] By adopting the above technical solution, the anionic surfactant is an amphiphilic substance. During the compound use of the polymer and the surfactant, the polymer plays a role in increasing the apparent viscosity of the aqueous phase and changing the mobility ratio between the displacement phase and the oil phase, while the surfactant can reduce the interfacial tension and generate a synergistic effect with the polymer.
[0022] Moreover, the anionic surfactant will generate micelles that play the role of "connection points" in the solution, connecting the hydrophobic groups between the molecular chains in the polyacrylamide, which is beneficial to enhancing the intermolecular association of the polyacrylamide to form a larger three-dimensional network structure. Thus, the apparent viscosity of the compound system gradually increases, and further improves the temperature resistance characteristics of the polyacrylamide.
[0023] Preferably, the anionic surfactant is sodium dodecyl sulfonate.
[0024] Second, a preparation method of a polyacrylamide for high-temperature oil displacement provided by the present application adopts the following technical solution: A preparation method of a polyacrylamide for high-temperature oil displacement comprises the following steps: Hydroxypropyl methylcellulose is added to deionized water and nitrogen is introduced. After being fully stirred, the mixture is heated, an initiator is added to react, and then a functional monomer is added. After the reaction is completed, precipitation, drying and extraction are performed in sequence to obtain polyacrylamide.
[0025] In summary, the present application includes at least one of the following beneficial technical effects: 1. Both hydroxypropyl methylcellulose and methyl allyl oxyethylene ether are temperature-sensitive. Methyl allyl oxyethylene ether has a long-chain alkyl structure with hydrophobic properties. Hydroxypropyl methylcellulose and methyl allyl oxyethylene ether contain many -OH groups, which form hydrogen bonds between polymer molecules and promote the formation of a three-dimensional network structure of polyacrylamide. As the temperature rises, the hydrophobic effect between the molecular chains increases, making polyacrylamide show a higher apparent viscosity at high temperatures, thereby improving the temperature resistance of polyacrylamide.
[0026] 2. Anionic surfactants will produce micelles in the solution that act as "connection points", connecting the hydrophobic groups between the molecular chains in polyacrylamide, which is beneficial to enhance the intermolecular association of polyacrylamide and form a larger three-dimensional network structure, thereby gradually increasing the apparent viscosity of the compound system and further improving the temperature resistance of polyacrylamide. DETAILED DESCRIPTION
[0027] The embodiments of the present application disclose a high temperature resistant polyacrylamide for oil displacement and a preparation method thereof.
[0028] The raw materials involved in this application can all be obtained commercially, among which hydroxypropyl methylcellulose (CAS No.: 9004-65-3) is provided by Zhejiang Haishen New Materials Co., Ltd., acrylamide (CAS No.: 79-06-1) is provided by Shandong Yukang Chemical Co., Ltd., methyl allyl oxyethylene ether (CAS No.: 27274-31-3) is provided by Guangdong Wengjiang Chemical Reagent Co., Ltd., sodium p-styrene sulfonate (CAS No.: 2695-37-6) is provided by Jinan Meigao Biotechnology Co., Ltd., methyl 2-bromobutyrate (CAS No.: 3196-15-4) is provided by Yancheng Longsheng Chemical Co., Ltd., and sodium dodecyl sulfonate (CAS No.: 2386-53-0) is provided by Shanghai Aladdin Biochemical Technology Co., Ltd.
[0029] Example 1 Polyacrylamide for high temperature oil recovery includes the following quality raw materials: Hydroxypropyl methylcellulose 1.1g, functional monomer 18g, initiator 0.08g, deionized water 80g.
[0030] Among them, the functional monomers include acrylamide, methallyloxyethyl ether, and sodium styrenesulfonate, and the mass ratio of acrylamide, methallyloxyethyl ether, and sodium styrenesulfonate is 1.5:1:0.1; the initiator is ammonium cerium nitrate.
[0031] The preparation method of the functional monomer includes the following steps: Mix acrylamide, methallyloxyethyl ether, and sodium styrenesulfonate, and stir evenly to obtain the functional monomer.
[0032] The preparation method of the polyacrylamide for high-temperature oil displacement includes the following steps: Add hydroxypropyl methylcellulose to deionized water, introduce nitrogen, stir well, heat to 55 °C, add the initiator and react for 15 min, then add the functional monomer. After the reaction, put the reaction product into excessive absolute ethanol for precipitation. When the surface of the product turns white and becomes slightly hard, vacuum dry it at 40 °C for 48 hours, and then further purify the product by solvent extraction method, using a mixed solution of formamide / acetic acid with a volume ratio of 1:1 as the solvent to obtain polyacrylamide.
[0033] Example 2 The polyacrylamide for high-temperature oil displacement includes the following raw materials by mass: 1.5 g of hydroxypropyl methylcellulose, 22 g of functional monomer, 0.12 g of initiator, and 100 g of deionized water.
[0034] Among them, the functional monomers include acrylamide, methallyloxyethyl ether, and sodium styrenesulfonate, and the mass ratio of acrylamide, methallyloxyethyl ether, and sodium styrenesulfonate is 1.9:1:0.1; the initiator is ammonium cerium nitrate.
[0035] The preparation method of the functional monomer includes the following steps: Mix acrylamide, methallyloxyethyl ether, and sodium styrenesulfonate, and stir evenly to obtain the functional monomer.
[0036] The preparation method of the polyacrylamide for high-temperature oil displacement includes the following steps: Add hydroxypropyl methylcellulose to deionized water, introduce nitrogen, stir well, heat to 55 °C, add the initiator and react for 15 min, then add the functional monomer. After the reaction, put the reaction product into excessive absolute ethanol for precipitation. When the surface of the product turns white and becomes slightly hard, vacuum dry it at 40 °C for 48 hours, and then further purify the product by solvent extraction method, using a mixed solution of formamide / acetic acid with a volume ratio of 1:1 as the solvent to obtain polyacrylamide.
[0037] Example 3 The polyacrylamide for high-temperature oil displacement includes the following raw materials by mass: 1.3 g of hydroxypropyl methylcellulose, 20 g of functional monomer, 0.10 g of initiator, and 90 g of deionized water.
[0038] The functional monomer includes acrylamide, methallyloxyethyl ether, and sodium styrene sulfonate, and the mass ratio of acrylamide, methallyloxyethyl ether, and sodium styrene sulfonate is 1.7:1:0.1; the initiator is ammonium cerium nitrate.
[0039] Preparation method of the functional monomer, comprising the following steps: After mixing acrylamide, methallyloxyethyl ether, and sodium styrene sulfonate, stir evenly to obtain the functional monomer.
[0040] Preparation method of polyacrylamide for high-temperature oil displacement, comprising the following steps: Add hydroxypropyl methylcellulose to deionized water, introduce nitrogen, stir thoroughly and heat to 55 °C, then add the initiator and react for 15 min, then add the functional monomer. After the reaction is completed, put the reaction product into excessive absolute ethanol for precipitation. When the surface of the product turns white and becomes slightly hard, vacuum dry at 40 °C for 48 hours, and then further purify the product by solvent extraction method, using a mixed solution of formamide / acetic acid with a volume ratio of 1:1 as the solvent, thereby obtaining polyacrylamide.
[0041] Example 4 The difference between Example 4 and Example 3 is that the mass ratio of acrylamide, methallyloxyethyl ether, and sodium styrene sulfonate in the functional monomer is 1.1:1:0.1.
[0042] Example 5 The difference between Example 5 and Example 3 is that the mass ratio of acrylamide, methallyloxyethyl ether, and sodium styrene sulfonate in the functional monomer is 2.3:1:0.1.
[0043] Example 6 The difference between Example 6 and Example 3 is that the polyacrylamide also includes 0.04 g of lignin-based macromolecular chain transfer agent.
[0044] Preparation method of the lignin-based macromolecular chain transfer agent, comprising the following steps: After mixing 1 g of lignin, 0.6 g of sodium hydroxide aqueous solution (the mass concentration of the sodium hydroxide aqueous solution is 80%), and 30 mL of dimethyl sulfoxide, perform ultrasonic treatment for 2 h, then add 1.2 g of carbon disulfide under an ice-water bath, react for 4.5 h, add 2.8 g of methyl 2-bromobutyrate, then react for 16 h and perform centrifugal separation, and then wash the obtained precipitate with deionized water and ether three times respectively. Finally, place the product in a vacuum dryer at 40 °C to obtain the lignin-based macromolecular chain transfer agent.
[0045] The preparation method of high temperature resistant polyacrylamide for oil displacement comprises the following steps: Hydroxypropyl methylcellulose was added into deionized water and nitrogen was introduced. After being fully stirred, it was heated to 55°C. Then an initiator was added to react for 15 minutes. Then functional monomers and lignin-based macromolecular chain transfer agents were added. After the reaction was completed, the reaction product was placed in an excess of anhydrous ethanol for precipitation. After the surface of the product turned white and slightly hardened, it was vacuum dried at 40°C for 48 hours. The product was further purified by solvent extraction, and a mixed solution of formamide / acetic acid with a volume ratio of 1:1 was used as a solvent to obtain polyacrylamide.
[0046] Example 7 The difference between Example 7 and Example 3 is that the polyacrylamide further includes 0.14 g of a lignin-based macromolecular chain transfer agent.
[0047] The preparation method of the lignin-based macromolecular chain transfer agent comprises the following steps: 1 g of lignin, 0.6 g of sodium hydroxide aqueous solution (the mass concentration of the sodium hydroxide aqueous solution is 80%), and 30 mL of dimethyl sulfoxide were mixed, and ultrasonically treated for 2 h. Then, 1.2 g of carbon disulfide was added in an ice water bath. After reacting for 4.5 h, 3.2 g of methyl 2-bromobutyrate was added. After reacting for 16 h, centrifugal separation was performed, and the obtained precipitate was washed with deionized water and ether for 3 times respectively. Finally, the product was placed at 40° C. and vacuum dried to obtain a lignin-based macromolecular chain transfer agent.
[0048] The preparation method of high temperature resistant polyacrylamide for oil displacement comprises the following steps: Hydroxypropyl methylcellulose was added into deionized water and nitrogen was introduced. After being fully stirred, it was heated to 55°C. Then an initiator was added to react for 15 minutes. Then functional monomers and lignin-based macromolecular chain transfer agents were added. After the reaction was completed, the reaction product was placed in an excess of anhydrous ethanol for precipitation. After the surface of the product turned white and slightly hardened, it was vacuum dried at 40°C for 48 hours. The product was further purified by solvent extraction, and a mixed solution of formamide / acetic acid with a volume ratio of 1:1 was used as a solvent to obtain polyacrylamide.
[0049] Example 8 The difference between Example 8 and Example 3 is that the polyacrylamide further includes 0.10 g of a lignin-based macromolecular chain transfer agent.
[0050] The preparation method of the lignin-based macromolecular chain transfer agent comprises the following steps: 1 g of lignin, 0.6 g of sodium hydroxide aqueous solution (the mass concentration of the sodium hydroxide aqueous solution is 80%), and 30 mL of dimethyl sulfoxide were mixed, and ultrasonically treated for 2 h. Then, 1.2 g of carbon disulfide was added in an ice water bath. After reacting for 4.5 h, 3.0 g of methyl 2-bromobutyrate was added. After reacting for 16 h, centrifugal separation was performed, and the obtained precipitate was washed with deionized water and ether for 3 times respectively. Finally, the product was placed at 40° C. and vacuum dried to obtain a lignin-based macromolecular chain transfer agent.
[0051] The preparation method of high temperature resistant polyacrylamide for oil displacement comprises the following steps: Hydroxypropyl methylcellulose was added into deionized water and nitrogen was introduced. After being fully stirred, it was heated to 55°C. Then an initiator was added to react for 15 minutes. Then functional monomers and lignin-based macromolecular chain transfer agents were added. After the reaction was completed, the reaction product was placed in an excess of anhydrous ethanol for precipitation. After the surface of the product turned white and slightly hardened, it was vacuum dried at 40°C for 48 hours. The product was further purified by solvent extraction, and a mixed solution of formamide / acetic acid with a volume ratio of 1:1 was used as a solvent to obtain polyacrylamide.
[0052] Example 9 The difference between Example 9 and Example 8 is that the mass ratio of lignin to methyl 2-bromobutyrate is 1:2.2.
[0053] Example 10 The difference between Example 10 and Example 8 is that the mass ratio of lignin to methyl 2-bromobutyrate is 1:3.8.
[0054] Embodiment 11 The difference between Example 11 and Example 8 is that the polyacrylamide further includes 2 g of anionic surfactant, and the anionic surfactant is sodium dodecyl sulfate.
[0055] The preparation method of high temperature resistant polyacrylamide for oil displacement comprises the following steps: Hydroxypropyl methylcellulose was added into deionized water, and nitrogen was introduced. After being fully stirred, it was heated to 55°C, and then an initiator was added to react for 15 minutes. Then, functional monomers, lignin-based macromolecular chain transfer agents and anionic surfactants were added. After the reaction was completed, the reaction product was placed in an excess of anhydrous ethanol for precipitation. After the surface of the product turned white and slightly hardened, it was vacuum dried at 40°C for 48 hours, and then the product was further purified by solvent extraction. A mixed solution of formamide / acetic acid with a volume ratio of 1:1 was used as a solvent to obtain polyacrylamide.
[0056] Example 12 Example 12 is different from Example 11 in that: the polyacrylamide further includes 6 g of an anionic surfactant, and the anionic surfactant is sodium dodecyl sulfonate.
[0057] Example 13 Example 13 is different from Example 11 in that: the polyacrylamide further includes 4 g of an anionic surfactant, and the anionic surfactant is sodium dodecyl sulfonate.
[0058] Comparative Example 1 Comparative Example 1 is different from Example 3 in that: the functional monomers include acrylamide and methallyloxyethyl ether, and the mass ratio of acrylamide to methallyloxyethyl ether is 1.5:1.
[0059] Comparative Example 2 Comparative Example 2 is different from Example 3 in that: the functional monomers only contain acrylamide.
[0060] Performance detection: The high-temperature and salt-resistant polyacrylamides obtained in the examples and comparative examples were respectively formulated into an aqueous solution with a weight of 0.15%, and the apparent viscosity of each aqueous solution was measured, and the test results were recorded in Table 1.
[0061] Among them, the apparent viscosity of the high-temperature and salt-resistant polyacrylamide aqueous solution was measured by a Brookfield viscometer, the test temperature was 100 °C, and the salinity was 48000 mg / L.
[0062] Table 1 Data analysis Specifically, the difference between Example 8 and Example 3 is that: the apparent viscosity of Example 8 is higher than that of Example 3. The analysis is as follows. The difference between Example 8 and Example 3 is that: the polyacrylamide further includes a lignin-based macromolecular chain transfer agent. The lignin-based macromolecular chain transfer agent in the reaction system can promote the contact and reaction of functional monomers, which is beneficial to the further reaction of functional monomers, thus helping to improve the temperature resistance of polyacrylamide.
[0063] Specifically, the difference between Example 13 and Example 8 is that: the apparent viscosity of Example 13 is higher than that of Example 8. The analysis is as follows. The difference between Example 13 and Example 8 is that: the polyacrylamide further includes sodium dodecyl sulfonate. Sodium dodecyl sulfonate can reduce the interfacial tension and enhance the intermolecular association of polyacrylamide to form a larger three-dimensional network structure, thus improving the temperature resistance of polyacrylamide.
[0064] The specific difference between Example 3 and Comparative Example 1 is as follows: The surface viscosity of Example 3 is higher than that of Comparative Example 1. The analysis is as follows. The difference between Example 3 and Comparative Example 1 is that in addition to acrylamide and methallyloxyethyl ether, the functional monomer also contains sodium p-styrenesulfonate. Sodium p-styrenesulfonate can improve the molecular stability of the polymer, and the sulfonic acid group can also effectively inhibit the hydrolysis of the polymer at high temperatures, protect the amide group, and thus improve the temperature resistance of polyacrylamide.
[0065] The specific difference between Example 3 and Comparative Example 2 is as follows: The surface viscosity of Example 3 is higher than that of Comparative Example 2. The analysis is as follows. The difference between Example 3 and Comparative Example 2 is that in addition to acrylamide, the functional monomer also includes methallyloxyethyl ether and sodium p-styrenesulfonate. Methallyloxyethyl ether has thermosensitivity, and the long-chain alkyl structure with hydrophobic properties forms hydrogen bonds between polymer molecules, promoting the formation of the three-dimensional network structure of polyacrylamide. As the temperature rises, the hydrophobic interaction between molecular chains increases, making polyacrylamide exhibit a higher apparent viscosity at high temperatures, which helps to improve the temperature resistance characteristics of polyacrylamide.
[0066] The above are all the preferred embodiments of this application. The protection scope of this application is not limited accordingly. Therefore, all equivalent changes made according to the structure, shape, and principle of this application should be covered within the protection scope of this application.
Claims
1. A polyacrylamide for high-temperature oil displacement, characterized in that: Including the following raw materials by mass: Hydroxypropyl methylcellulose 1.1-1.5 parts Functional monomer 18-22 parts Initiator 0.08-0.12 parts 80-100 parts of deionized water The functional monomers include acrylamide and methyl allyl oxyethylene ether.
2. The polyacrylamide for high-temperature oil displacement according to claim 1, characterized in that: The functional monomer also includes sodium p-styrene sulfonate.
3. The polyacrylamide for high-temperature oil displacement according to claim 2, characterized in that: The mass ratio of acrylamide, methyl allyl oxyethylene ether and sodium styrene sulfonate is (1.5-1.9):1:0.
1.
4. The polyacrylamide for high-temperature oil displacement according to claim 2, characterized in that: The polyacrylamide also includes 0.04-0.14 parts of lignin-based macromolecular chain transfer agent.
5. The polyacrylamide for high-temperature oil displacement according to claim 4, characterized in that: The preparation method of the lignin-based macromolecular chain transfer agent comprises the following steps: Lignin, sodium hydroxide aqueous solution and dimethyl sulfoxide are mixed and stirred evenly, and carbon disulfide is added in an ice water bath. After the reaction is completed, methyl 2-bromobutyrate is added, and then centrifugation is performed after the reaction. The obtained precipitate is washed and dried in sequence to obtain a lignin-based macromolecular chain transfer agent.
6. The polyacrylamide for high-temperature oil displacement according to claim 5, characterized in that: The mass ratio of the lignin to methyl 2-bromobutyrate is 1:(2.8-3.2).
7. A polyacrylamide for high-temperature oil displacement according to claim 1, characterized in that: 2-6 parts of anionic surfactant are also added into the polyacrylamide.
8. The polyacrylamide for high-temperature oil displacement according to claim 8, wherein: The anionic surfactant is sodium dodecyl sulfate.
9. A method for preparing the high temperature resistant polyacrylamide for oil displacement as claimed in claim 1, comprising the following steps: Hydroxypropyl methylcellulose is added to deionized water and nitrogen is introduced. After being fully stirred, the mixture is heated, an initiator is added to react, and then a functional monomer is added. After the reaction is completed, precipitation, drying and extraction are performed in sequence to obtain polyacrylamide.