Branched particle polymer for oil extraction and preparation method thereof
By preparing branched particulate polymers, the stability and injectability issues of polyacrylamide under high salt and shear conditions were solved, thereby improving oil recovery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- 黑龙江吉地油田服务股份有限公司
- Filing Date
- 2026-01-12
- Publication Date
- 2026-04-24
AI Technical Summary
Existing polyacrylamide has problems with poor salt resistance, poor shear resistance and poor injection properties in tertiary oil recovery, which leads to a decrease in oil recovery rate.
A branched particulate polymer preparation method was adopted, which introduced functional monomers, surfactants, oxidants, reducing agents and chain extenders to form a polymer that maintains good salt resistance and shear resistance under oilfield wastewater conditions.
It improved oil recovery, enhanced the stability and injectability of polymers under high salinity and shear conditions, and improved the oil displacement effect.
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Abstract
Description
Technical Field
[0001] This invention relates to the field of petroleum extraction technology, specifically to a branched particulate polymer for oil extraction and its preparation method. Background Technology
[0002] Tertiary oil recovery technology has become one of the main measures for improving crude oil recovery rates in China, and the polymer currently used in oil recovery is mainly polyacrylamide. Polyacrylamide has advantages such as high solid content and low transportation costs, but it also has disadvantages such as poor solubility, fisheye problem, poor shear resistance, and poor injectability. With the development of tertiary oil recovery technology, oilfields have placed higher demands on the performance of polymers used for oil displacement. Ordinary polyacrylamide is no longer suitable for the exploitation of this oil reservoir, and the oil recovery rate is constantly declining. Therefore, higher requirements are now being placed on the injectability, shear resistance, and salt resistance of the polymers used. Summary of the Invention
[0003] The purpose of this invention is to overcome the shortcomings of the prior art and provide a branched particulate polymer for oil production and its preparation method. It has the advantages of good salt resistance, stable performance, shear resistance and excellent injectability. Because it exhibits extremely strong shear thinning characteristics, it can still maintain good salt resistance and shear resistance under oilfield wastewater conditions, and can significantly improve oil recovery rate.
[0004] To address the problems existing in the background technology, the present invention adopts the following technical solution: comprising acrylamide, functional monomer 1, functional monomer 2, surfactant, water, oxidant, reducing agent, and chain extender, wherein acrylamide is 70-100 parts, functional monomer 1 is 20-40 parts, functional monomer 2 is 10-15 parts, surfactant is 10-20 parts, water is 400-500 parts, oxidant is 0.01-0.2 parts, reducing agent is 0.01-0.2 parts, and chain extender is 0.1-0.5 parts.
[0005] The structural formula of the functional unit 1 is as follows: .
[0006] The structural formula of the functional unit 2 is as follows: .
[0007] The preparation method of the aforementioned functional monomer 1 is as follows: Step 1: Add 5 parts of 2-naphthoic acid and 20 parts of anhydrous methanol to a dry 50mL round-bottom flask, stir to mix evenly, slowly add 2 parts of concentrated sulfuric acid, install a reflux condenser, heat in an oil bath to reflux to 70-80℃, and react for 6-8 hours. After the reaction is complete, cool to room temperature, and transfer the reaction solution to a beaker containing 50mL of ice water. While stirring, slowly add saturated Na2CO3 solution until the solution is alkaline with a pH of 8-9. Extract with 3×30 parts of ethyl acetate, combine the organic phases, dry with anhydrous Na2SO4, filter to remove the drying agent, and distill off ethyl acetate and excess methanol under reduced pressure to obtain crude methyl 2-naphthoic acid. Then purify by reduced pressure distillation to obtain the pure product. Step 2: Add 3 parts of methyl 2-naphthoic acid ester and 20 parts of carbon tetrachloride obtained in Step 1 to a dry 50mL round-bottom flask, stir to dissolve, and slowly add 2 parts of liquid bromine dropwise under light conditions, controlling the reaction temperature at around room temperature during the dropwise addition. After the dropwise addition is complete, continue stirring for 3-4 hours until the reddish-brown bromine in the solution disappears. After the reaction is complete, add 10 parts of saturated Na2SO4 solution to the reaction solution and stir for 10 minutes to remove bromine. Then separate the liquid and liquid phases. Dry the organic phase with anhydrous Na2SO4, filter, and distill off carbon tetrachloride under reduced pressure to obtain methyl 6-bromo-2-naphthoic acid ester. Step 3: Under anhydrous and oxygen-free conditions, the reaction apparatus is connected to an inert gas balloon, and argon gas is purged throughout the process. Two parts of methyl 6-bromo-2-naphthoate, 1.5 parts of 4-pentenyl zinc chloride (prepared by reacting 4-pentenyl bromine with zinc powder in anhydrous THF, freshly prepared), 5 parts of Pd(dppf)Cl2, and 15 parts of anhydrous THF are added to a dry Schlenk tube. The reaction system is placed in an oil bath, heated to 60°C, and stirred for 12 hours. After the reaction is complete, the reaction solution is cooled to room temperature, and 10 parts of saturated NH4Cl solution are added to quench the reaction. The mixture is extracted with 3 × 20 parts of ethyl acetate, the organic phases are combined, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue is purified by column chromatography with a petroleum ether to ethyl acetate ratio of 15:1 to obtain methyl 6-(4-pentenyl)-2-naphthoate. Step 4: In a 100 mL round-bottom flask, add 1.5 parts of methyl 6(4-pentenyl)-2-naphthoic acid, 20 parts of 10% NaOH aqueous solution and 10 parts of methanol. Install a reflux condenser and heat under reflux for 4-6 hours. After the reaction is complete, cool to room temperature and remove methanol by vacuum distillation. Acidify the remaining aqueous solution with 1 mol / L dilute hydrochloric acid to pH=2-3. A solid will precipitate. Filter the solid, collect it, wash it with cold water, and dry it to obtain 6(4-pentenyl)-2-naphthoic acid. Step 5: In a dry 50mL round-bottom flask, add 1 part of 6(4-pentenyl)-2-naphthoic acid, 0.5 parts of phenol and 0.5 parts of concentrated sulfuric acid. Heat in an oil bath to 120℃ with stirring and react for 4-5 hours. After the reaction is complete, cool to room temperature and pour the reaction solution into a beaker containing 30 parts of ice water. Slowly add saturated Na2CO3 solution with stirring until the solution is neutral. Extract with 3×20 parts of ethyl acetate, combine the organic phases, dry with anhydrous Na2SO4, filter and concentrate under reduced pressure to obtain the target product phenyl 6(4-pentenyl)-2-naphthoic acid.
[0008] The surfactant is any one of sodium dodecyl sulfate (SDS), α-olefin sulfonate (AOS), or petroleum sulfonate.
[0009] The oxidant is any one of ammonium persulfate, potassium persulfate, and sodium persulfate.
[0010] The reducing agent is any one of sodium bisulfite, sodium thiosulfate, and triethanolamine.
[0011] The chain extender is either tetramethylenediamine or hexamethylenetetramine.
[0012] The preparation method of branched particulate polymer for oil production is as follows: (1) Mix acrylamide, functional monomer 1, functional monomer 2, surfactant and water evenly, and adjust the pH value to 7.4~7.6 with 30% sodium hydroxide solution; (2) Add the solution prepared in step (1) into an adiabatic polymerization reactor, introduce nitrogen gas, remove oxygen for 30 minutes, add chain extender, oxidant and reducing agent, react for a period of time, and when the solution becomes viscous, stop introducing nitrogen gas, continue the reaction for 4-6 hours to obtain polymer colloid; (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production.
[0013] The beneficial effects of this invention are as follows: This invention addresses the problems of salt resistance, fisheye effect, shear resistance, and injection properties of existing polyacrylamide by introducing functional monomers into the polymerization formulation. This better solves the shortcomings of unstable performance, poor shear resistance, and poor injection properties, enabling it to maintain good salt resistance and shear resistance even under oilfield wastewater conditions, and significantly improve oil recovery rate. Detailed Implementation
[0014] The present invention specifically adopts the following embodiments: including acrylamide, functional monomer 1, functional monomer 2, surfactant, water, oxidant, reducing agent and chain extender, wherein acrylamide is 70-100 parts, functional monomer 1 is 20-40 parts, functional monomer 2 is 10-15 parts, surfactant is 10-20 parts, water is 400-500 parts, oxidant is 0.01-0.2 parts, reducing agent is 0.01-0.2 parts and chain extender is 0.1-0.5 parts.
[0015] The structural formula of the functional unit 1 is as follows: .
[0016] The structural formula of the functional unit 2 is as follows: .
[0017] The preparation method of the aforementioned functional monomer 1 is as follows: Step 1: Add 5 parts of 2-naphthoic acid and 20 parts of anhydrous methanol to a dry 50mL round-bottom flask, stir to mix evenly, slowly add 2 parts of concentrated sulfuric acid, install a reflux condenser, heat in an oil bath to reflux to 70-80℃, and react for 6-8 hours. After the reaction is complete, cool to room temperature, and transfer the reaction solution to a beaker containing 50mL of ice water. While stirring, slowly add saturated Na2CO3 solution until the solution is alkaline with a pH of 8-9. Extract with 3×30 parts of ethyl acetate, combine the organic phases, dry with anhydrous Na2SO4, filter to remove the drying agent, and distill off ethyl acetate and excess methanol under reduced pressure to obtain crude methyl 2-naphthoic acid. Then purify by reduced pressure distillation to obtain the pure product. Step 2: Add 3 parts of methyl 2-naphthoic acid ester and 20 parts of carbon tetrachloride obtained in Step 1 to a dry 50mL round-bottom flask, stir to dissolve, and slowly add 2 parts of liquid bromine dropwise under light conditions, controlling the reaction temperature at around room temperature during the dropwise addition. After the dropwise addition is complete, continue stirring for 3-4 hours until the reddish-brown bromine in the solution disappears. After the reaction is complete, add 10 parts of saturated Na2SO4 solution to the reaction solution and stir for 10 minutes to remove bromine. Then separate the liquid and liquid phases. Dry the organic phase with anhydrous Na2SO4, filter, and distill off carbon tetrachloride under reduced pressure to obtain methyl 6-bromo-2-naphthoic acid ester. Step 3: Under anhydrous and oxygen-free conditions, the reaction apparatus is connected to an inert gas balloon, and argon gas is purged throughout the process. Two parts of methyl 6-bromo-2-naphthoate, 1.5 parts of 4-pentenyl zinc chloride (prepared by reacting 4-pentenyl bromine with zinc powder in anhydrous THF, freshly prepared), 5 parts of Pd(dppf)Cl2, and 15 parts of anhydrous THF are added to a dry Schlenk tube. The reaction system is placed in an oil bath, heated to 60°C, and stirred for 12 hours. After the reaction is complete, the reaction solution is cooled to room temperature, and 10 parts of saturated NH4Cl solution are added to quench the reaction. The mixture is extracted with 3 × 20 parts of ethyl acetate, the organic phases are combined, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue is purified by column chromatography with a petroleum ether to ethyl acetate ratio of 15:1 to obtain methyl 6-(4-pentenyl)-2-naphthoate. Step 4: In a 100 mL round-bottom flask, add 1.5 parts of methyl 6(4-pentenyl)-2-naphthoic acid, 20 parts of 10% NaOH aqueous solution and 10 parts of methanol. Install a reflux condenser and heat under reflux for 4-6 hours. After the reaction is complete, cool to room temperature and remove methanol by vacuum distillation. Acidify the remaining aqueous solution with 1 mol / L dilute hydrochloric acid to pH=2-3. A solid will precipitate. Filter the solid, collect it, wash it with cold water, and dry it to obtain 6(4-pentenyl)-2-naphthoic acid. Step 5: In a dry 50mL round-bottom flask, add 1 part of 6(4-pentenyl)-2-naphthoic acid, 0.5 parts of phenol and 0.5 parts of concentrated sulfuric acid. Heat in an oil bath to 120℃ with stirring and react for 4-5 hours. After the reaction is complete, cool to room temperature and pour the reaction solution into a beaker containing 30 parts of ice water. Slowly add saturated Na2CO3 solution with stirring until the solution is neutral. Extract with 3×20 parts of ethyl acetate, combine the organic phases, dry with anhydrous Na2SO4, filter and concentrate under reduced pressure to obtain the target product phenyl 6(4-pentenyl)-2-naphthoic acid.
[0018] The synthesis principle of functional monomer 1 is as follows:
[0019] The synthesis principle of the auxiliary agent 4-pentenyl zinc chloride is as follows:
[0020] The surfactant is any one of sodium dodecyl sulfate (SDS), α-olefin sulfonate (AOS), or petroleum sulfonate. The oxidizing agent is any one of ammonium persulfate, potassium persulfate, or sodium persulfate. The reducing agent is any one of sodium bisulfite, sodium thiosulfate, or triethanolamine. The chain extender is any one of tetramethylenediamine or hexamethylenetetramine.
[0021] The preparation method of branched particulate polymer for oil production is as follows: (1) Mix acrylamide, functional monomer 1, functional monomer 2, surfactant and water evenly, and adjust the pH value to 7.4~7.6 with 30% sodium hydroxide solution; (2) Add the solution prepared in step (1) into an adiabatic polymerization reactor, introduce nitrogen gas, remove oxygen for 30 minutes, add chain extender, oxidant and reducing agent, react for a period of time, and when the solution becomes viscous, stop introducing nitrogen gas, continue the reaction for 4-6 hours to obtain polymer colloid; (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production. Example 1
[0022] A branched particulate polymer for oil extraction and its preparation method: (1) Mix 90 parts acrylamide, 30 parts functional monomer 1, 12 parts functional monomer 2, 10 parts α-olefin sulfonate (AOS), and 500 parts water until homogeneous, and adjust the pH to 7.4-7.6 with 30% NaOH. (2) Pour the solution prepared in step (1) into an adiabatic polymerization reactor, purge with nitrogen to remove oxygen for 30 minutes, then add 0.5 parts of tetramethylenediamine, 0.05 parts of ammonium persulfate and 0.05 parts of sodium bisulfite respectively. After reacting for a period of time, when the solution becomes viscous, stop purging with nitrogen and continue reacting for 4-6 hours to obtain polymer colloid.
[0023] (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production. Example 2
[0024] A branched particulate polymer for oil extraction and its preparation method: (1) Mix 100 parts acrylamide, 35 parts functional monomer 1, 12 parts functional monomer 2, 10 parts α-olefin sulfonate (AOS), and 500 parts water until homogeneous, and adjust the pH value to 7.4-7.6 with 30% NaOH.
[0025] (2) Pour the solution prepared in step (1) into an adiabatic polymerization reactor, purge with nitrogen to remove oxygen for 30 minutes, and then add 0.5 parts of tetramethylenediamine, 0.1 parts of ammonium persulfate and 0.1 parts of sodium bisulfite respectively. After reacting for a period of time, when the solution becomes viscous, stop purging with nitrogen and continue reacting for 4-6 hours to obtain polymer colloid.
[0026] (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production. Example 3
[0027] A branched particulate polymer for oil extraction and its preparation method: (1) Mix 90 parts acrylamide, 40 parts functional monomer 1, 15 parts functional monomer 2, 20 parts sodium dodecyl sulfate (SDS), and 500 parts water until homogeneous, and adjust the pH value to 7.4-7.6 with 30% NaOH.
[0028] (2) Pour the solution prepared in step (1) into an adiabatic polymerization reactor, purge with nitrogen to remove oxygen for 30 minutes, and then add 0.5 parts of tetramethylenediamine, 0.15 parts of ammonium persulfate and 0.15 parts of sodium bisulfite respectively. After reacting for a period of time, when the solution becomes viscous, stop purging with nitrogen and continue reacting for 4-6 hours to obtain polymer colloid.
[0029] (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production. Example 4
[0030] A branched particulate polymer for oil extraction and its preparation method: (1) Mix 100 parts acrylamide, 40 parts functional monomer 1, 14 parts functional monomer 2, 20 parts sodium dodecyl sulfate (SDS), and 500 parts water until homogeneous, and adjust the pH value to 7.4-7.6 with 30% NaOH.
[0031] (2) Pour the solution prepared in step (1) into an adiabatic polymerization reactor, purge with nitrogen to remove oxygen for 30 minutes, and then add 0.5 parts of tetramethylenediamine, 0.2 parts of ammonium persulfate and 0.2 parts of sodium bisulfite respectively. After reacting for a period of time, when the solution becomes viscous, stop purging with nitrogen and continue reacting for 4-6 hours to obtain polymer colloid.
[0032] (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production. Example 5
[0033] A branched particulate polymer for oil extraction and its preparation method: (1) Mix 70 parts acrylamide, 25 parts functional monomer 1, 10 parts functional monomer 2, 15 parts petroleum sulfonate, and 400 parts water until homogeneous, and adjust the pH value to 7.4-7.6 with 30% NaOH.
[0034] (2) Pour the solution prepared in step (1) into an adiabatic polymerization reactor, purge with nitrogen to remove oxygen for 30 minutes, and then add 0.1 parts of tetramethylenediamine, 0.01 parts of ammonium persulfate and 0.01 parts of sodium bisulfite respectively. After reacting for a period of time, when the solution becomes viscous, stop purging with nitrogen and continue reacting for 4-6 hours to obtain polymer colloid.
[0035] (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production. Example 6
[0036] A branched particulate polymer for oil extraction and its preparation method: (1) Mix 80 parts acrylamide, 20 parts functional monomer 1, 10 parts functional monomer 2, 15 parts petroleum sulfonate, and 400 parts water until homogeneous, and adjust the pH value to 7.4-7.6 with 30% NaOH.
[0037] (2) Pour the solution prepared in step (1) into an adiabatic polymerization reactor, purge with nitrogen to remove oxygen for 30 minutes, and then add 0.1 parts of tetramethylenediamine, 0.01 parts of ammonium persulfate and 0.01 parts of sodium bisulfite respectively. After reacting for a period of time, when the solution becomes viscous, stop purging with nitrogen and continue reacting for 4-6 hours to obtain polymer colloid.
[0038] (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production.
[0039] Experimental Example 1 The physicochemical properties of branched particulate polymers used in oil production were evaluated in experiments 1-6, and the results are shown in Table 1: Table 1. Physicochemical properties of branched particulate polymers used in oil production
[0040] As can be seen from the data in Table 1, the viscosity of Examples 1-6 was high when tested according to the polyacrylamide standard. The branched particulate polymer for oil extraction in this patent can be adjusted according to the reaction conditions and the material addition ratio to obtain polyacrylamide with a volume expansion ratio in the range of 45-52.
[0041] Experimental Example 2 This experimental example illustrates viscosity stability evaluation. Wastewater from an oilfield in Daqing was used to prepare a polymer concentration of 1000 mg / L using a wastewater-to-dilute ratio. The viscosity stability of the system under anaerobic conditions was evaluated, and compared with that of a common high-molecular-weight polymer. Viscosity testing was conducted at 0, 3, 7, 15, 30, 60, and 90 days. The results are shown in Table 2. Table 2. Viscosity stability results of branched particulate polymers used in oil production.
[0042] As shown in the table, the viscosity of the branched particulate polymer for oil production in Examples 1-6 of this invention is greater than 200 mPa·s after 90 days, showing a linear increase. In contrast, the viscosity of the ordinary polymer in the control group is only 4.6 mPa·s after 90 days. This indicates that the branched particulate polymer for oil production of this invention has good resistance to sewage and can play a long-term migration role in the bottom displacement process.
[0043] Experimental Example 3 This experiment illustrates the evaluation of salt resistance. Sodium chloride solutions of different concentrations (from 5000 mg / L to 20000 mg / L) were prepared. The products from Examples 1-6 were diluted to a concentration of 1000 mg / L using a method of diluting the contaminated solution with the contaminated solution. Viscosity was measured using a Brookfield viscometer DVⅡ at a constant temperature of 45°C. Ordinary polyacrylamide was used as a control under the same conditions. The viscosity measurement results are shown in Table 3. Table 3 Salt resistance test results
[0044] As shown in Table 3, the viscosity decreases slightly with increasing mineralization. The higher the amount of functional monomer, the less the viscosity is affected by mineralization, proving that it has strong salt resistance. The viscosity of ordinary polymers has been decreasing with increasing mineralization. By adding functional monomers, the salt resistance is significantly better than that of ordinary polymers.
[0045] Experimental Example 4 This experiment illustrates the evaluation of shear resistance. Wastewater from a Daqing oilfield was used, and a polymer concentration of 1500 mg / L was prepared by mixing wastewater with wastewater and diluting it. After shearing using a Wu Yin mixer, the viscosity was measured using a Brookfield viscometer DVⅡ at a constant temperature of 45℃. Ordinary polyacrylamide was used as a control under the same conditions. The viscosity measurement results are shown in Table 4. Table 4 Shear resistance test results
[0046] As shown in Table 4, the viscosity retention rate after shearing in Examples 1-6 is greater than 88%, and with the increase of functional monomers, the viscosity retention rate after shearing also increases from 88.35% to 93.05%. In contrast, the viscosity retention rate of ordinary polymers in the control group after shearing is only 34.05%, indicating that the branched particulate polymer for oil production of the present invention has shear resistance.
[0047] In summary, this branched particulate polymer for oil recovery and its preparation method address the issues of salt resistance, fisheye problem, shear resistance, and injection performance of existing polyacrylamide technologies. By introducing functional monomers into the polymerization formulation, it can better solve the shortcomings of unstable performance, poor shear resistance, and poor injection performance. This allows it to maintain good salt resistance and shear resistance even under oilfield wastewater conditions, and can significantly improve oil recovery.
Claims
1. A branched particulate polymer for oil extraction, characterized in that: It includes acrylamide, functional monomer 1, functional monomer 2, surfactant, water, oxidant, reducing agent and chain extender, wherein acrylamide is 70-100 parts, functional monomer 1 is 20-40 parts, functional monomer 2 is 10-15 parts, surfactant is 10-20 parts, water is 400-500 parts, oxidant is 0.01-0.2 parts, reducing agent is 0.01-0.2 parts and chain extender is 0.1-0.5 parts.
2. The branched particulate polymer for oil production according to claim 1, characterized in that: The structural formula of the functional unit 1 is as follows: 。 3. The branched particulate polymer for oil production according to claim 1, characterized in that: The structural formula of the functional unit 2 is as follows: 。 4. The branched particulate polymer for oil production according to claim 1, characterized in that: The preparation method of the aforementioned functional monomer 1 is as follows: Step 1: Add 5 parts of 2-naphthoic acid and 20 parts of anhydrous methanol to a dry 50mL round-bottom flask, stir to mix evenly, slowly add 2 parts of concentrated sulfuric acid, install a reflux condenser, heat in an oil bath to reflux to 70-80℃, and react for 6-8 hours. After the reaction is complete, cool to room temperature, and transfer the reaction solution to a beaker containing 50mL of ice water. While stirring, slowly add saturated Na2CO3 solution until the solution is alkaline with a pH of 8-9. Extract with 3×30 parts of ethyl acetate, combine the organic phases, dry with anhydrous Na2SO4, filter to remove the drying agent, and distill off ethyl acetate and excess methanol under reduced pressure to obtain crude methyl 2-naphthoic acid. Then purify by reduced pressure distillation to obtain the pure product. Step 2: Add 3 parts of methyl 2-naphthoic acid ester and 20 parts of carbon tetrachloride obtained in Step 1 to a dry 50mL round-bottom flask, stir to dissolve, and slowly add 2 parts of liquid bromine dropwise under light conditions, controlling the reaction temperature at around room temperature during the dropwise addition. After the dropwise addition is complete, continue stirring for 3-4 hours until the reddish-brown bromine in the solution disappears. After the reaction is complete, add 10 parts of saturated Na2SO4 solution to the reaction solution and stir for 10 minutes to remove bromine. Then separate the liquid and liquid phases. Dry the organic phase with anhydrous Na2SO4, filter, and distill off carbon tetrachloride under reduced pressure to obtain methyl 6-bromo-2-naphthoic acid ester. Step 3: Under anhydrous and oxygen-free conditions, the reaction apparatus is connected to an inert gas balloon, and argon gas is purged throughout the process. Two parts of methyl 6-bromo-2-naphthoate, 1.5 parts of 4-pentenyl zinc chloride (prepared by reacting 4-pentenyl bromine with zinc powder in anhydrous THF, freshly prepared), 5 parts of Pd(dppf)Cl2, and 15 parts of anhydrous THF are added to a dry Schlenk tube. The reaction system is placed in an oil bath, heated to 60°C, and stirred for 12 hours. After the reaction is complete, the reaction solution is cooled to room temperature, and 10 parts of saturated NH4Cl solution are added to quench the reaction. The mixture is extracted with 3 × 20 parts of ethyl acetate, the organic phases are combined, dried over anhydrous Na2SO4, filtered, and concentrated under reduced pressure. The residue is purified by column chromatography with a petroleum ether to ethyl acetate ratio of 15:1 to obtain methyl 6-(4-pentenyl)-2-naphthoate. Step 4: In a 100 mL round-bottom flask, add 1.5 parts of methyl 6(4-pentenyl)-2-naphthoic acid, 20 parts of 10% NaOH aqueous solution and 10 parts of methanol. Install a reflux condenser and heat under reflux for 4-6 hours. After the reaction is complete, cool to room temperature and remove methanol by vacuum distillation. Acidify the remaining aqueous solution with 1 mol / L dilute hydrochloric acid to pH=2-3. A solid will precipitate. Filter the solid, collect it, wash it with cold water, and dry it to obtain 6(4-pentenyl)-2-naphthoic acid. Step 5: In a dry 50mL round-bottom flask, add 1 part of 6(4-pentenyl)-2-naphthoic acid, 0.5 parts of phenol and 0.5 parts of concentrated sulfuric acid. Heat in an oil bath to 120℃ with stirring and react for 4-5 hours. After the reaction is complete, cool to room temperature and pour the reaction solution into a beaker containing 30 parts of ice water. Slowly add saturated Na2CO3 solution with stirring until the solution is neutral. Extract with 3×20 parts of ethyl acetate, combine the organic phases, dry with anhydrous Na2SO4, filter and concentrate under reduced pressure to obtain the target product phenyl 6(4-pentenyl)-2-naphthoic acid.
5. The branched particulate polymer for oil production according to claim 1, characterized in that: The surfactant is any one of sodium dodecyl sulfate (SDS), α-olefin sulfonate (AOS), or petroleum sulfonate.
6. The branched particulate polymer for oil production according to claim 1, characterized in that: The oxidant is any one of ammonium persulfate, potassium persulfate, and sodium persulfate.
7. The branched particulate polymer for oil production according to claim 1, characterized in that: The reducing agent is any one of sodium bisulfite, sodium thiosulfate, and triethanolamine.
8. The branched particulate polymer for oil production according to claim 1, characterized in that: The chain extender is either tetramethylenediamine or hexamethylenetetramine.
9. The method for preparing a branched particulate polymer for oil production according to claim 1, characterized in that: The specific operating method is as follows: (1) Mix acrylamide, functional monomer 1, functional monomer 2, surfactant and water evenly, and adjust the pH value to 7.4~7.6 with 30% sodium hydroxide solution; (2) Add the solution prepared in step (1) into an adiabatic polymerization reactor, introduce nitrogen gas, remove oxygen for 30 minutes, add chain extender, oxidant and reducing agent, react for a period of time, and when the solution becomes viscous, stop introducing nitrogen gas, continue the reaction for 4-6 hours to obtain polymer colloid; (3) Granulate the polymer colloid obtained in step (2), add sodium hydroxide, mix thoroughly, hydrolyze at 50-80℃ for 5-7 hours, dry for 6-10 hours, and pulverize. Sieve to obtain branched granulated polymer dry powder for oil production.