Amphiphilic block poly-surfactant containing surfactant functional group and preparation method of amphiphilic block poly-surfactant

Abstract

The invention relates to the field of oilfield chemistry, in particular to an amphiphilic block poly-surfactant containing a surfactant functional group and a preparation method of the amphiphilic block poly-surfactant. Through molecular structure design, a self-made amphiphilic block copolymer macromonomer is added, a side chain of the macromonomer has a hydrophobic polycaprolactone block and a hydrophilic polyethylene glycol block at the same time, and the side chain with the built-in amphiphilic block integrates strong emulsification stripping and hydrophobic association effects at the same time; due to the strong emulsifying and stripping capacity to residual oil after water flooding and the deep profile control capacity to a reservoir, the recovery efficiency of an oil reservoir after water flooding is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of oil field chemistry, in particular to an amphiphilic block poly-surfactant containing surfactant functional groups and a preparation method thereof. BACKGROUND

[0002] With the deepening of oil exploitation, the recoverable reserves and production of conventional crude oil are decreasing, and the resources of oil fields need to be utilized as much as possible. After long-term water flooding (secondary oil recovery), due to the heterogeneity of the formation, the injected water is prone to channeling along the high permeability channels, and the crude oil in the low permeability regions or small pores cannot be driven by water; on the other hand, due to the high oil-water interfacial tension, a lot of crude oil will be retained in the rock pores in the form of oil droplets or oil films, which cannot be stripped and taken away by water, resulting in a large amount of crude oil that cannot be recovered; tertiary oil recovery, also known as enhanced oil recovery, refers to a series of physical, chemical or biological technologies used to further recover more residual crude oil that is difficult to exploit in the ground after the use of natural energy exploitation and the maintenance of formation pressure by water injection, gas injection and other artificial methods. Among them, chemical flooding is the most commonly used method in oil fields, which is divided into polymer flooding, surfactant flooding and alkali flooding. Polymer flooding: adding high molecular polymer (such as polyacrylamide) to water to increase the viscosity of water and improve the water-oil mobility ratio, so that water can uniformly advance; surfactant flooding is to reduce the oil-water interfacial tension by surfactant, so that the residual oil droplets are more easily deformed, started and flowed; alkali flooding is to react alkali with acidic substances in crude oil to generate surfactant in situ, which has similar effects.

[0003] Poly-surfactant is a new development direction of chemical flooding, which integrates the functional groups of polymer and surfactant into one molecule, forming a one-component system with dual functions of viscosity increase and interfacial tension reduction / emulsification. Poly-surfactant combines the advantages of polymer and surfactant, and can increase viscosity, expand the swept volume, and improve the solubilizing and emulsifying capacity of crude oil without alkali.

[0004] CN104231165A discloses a preparation method of a poly-surfactant for oil displacement, which uses acrylamide, 2-acrylamido-2-methylpropane sulfonic acid sodium, 2-acrylamido alkyl sulfonic acid sodium and sodium acrylate as monomers, and adopts a water solution four-component copolymerization method to prepare a poly-surfactant for oil displacement. The temperature resistance of the poly-surfactant is better than that of conventional polymers, and the viscosity retention rate of its aqueous solution is greater than 80% after 7 days at 95℃.

[0005] CN115109204A discloses an organic silicone poly-surfactant composed of alpha-olefin polymethylsiloxane and 2-4 kinds of monomers of acrylamide monomer, sodium acrylate monomer, 2-acrylamide-2-methylpropane sulfonic acid sodium monomer, and allyloxy nonylphenol polyoxyethylene ether monomer. The poly-surfactant of the patent has strong emulsifying and dispersing capacity for thick oil, and the product can reduce the oil-water interfacial tension and improve the water phase wettability of the oil reservoir.

[0006] The poly-surfactants in the prior art are all acrylamide copolymers, and functional groups such as fragrances, long-chain alkyl groups, and anionic / cationic groups are introduced into the side chains through other functional monomers. Although the above poly-surfactants combine the advantages of polymer tackifying and surfactant emulsifying, the recovery rate still needs to be improved. SUMMARY

[0007] The present application aims to overcome the shortcomings of the prior art and provide an amphiphilic block poly-surfactant containing surfactant functional groups and a preparation method thereof. The method adds a self-made amphiphilic block copolymer macromonomer through molecular structure design, and the side chain of the macromonomer has both hydrophobic polycaprolactone blocks and hydrophilic polyethylene glycol blocks. This built-in amphiphilic block side chain integrates strong emulsifying and peeling and hydrophobic association effects, and has strong emulsifying and peeling capacity for remaining oil after water flooding and deep profile control capacity for reservoirs. Specifically, the present application provides the following technical solutions: An amphiphilic block poly-surfactant containing surfactant functional groups is obtained by copolymerization of the following monomers in mass parts: 100 parts of acrylamide, 6-10 parts of a hydrophobic association monomer, 20-40 parts of an amphiphilic block copolymer macromonomer, 20-30 parts of an unsaturated acid salt, and 3-5 parts of a bis-ether fluorene acrylate; the amphiphilic block copolymer macromonomer comprises the following raw materials in mole parts: 1 mole part of polycaprolactone, 2-2.2 mole parts of diisocyanate, and 1.1-1.3 mole parts of polyethylene glycol methacrylate ester.

[0008] Furthermore, the amphiphilic block copolymer containing surfactant functional groups has a viscosity-average molecular weight of 12-15 million, which is measured using a five-point dilution method with an Ubbelohde viscometer. As a polymer for oilfield flooding, a high molecular weight is generally required; the viscosity-average molecular weight needs to exceed 10 million to achieve excellent oil displacement effects. To prepare high molecular weight acrylamide copolymers, this invention controls the polymerization reaction conditions, employing low-temperature polymerization to reduce the chain termination rate and reacting under an inert atmosphere. In addition, the use of surfactants is minimized, as their presence can reduce the polymer's molecular weight. The amphiphilic block copolymer containing surfactant functional groups of this invention contains both hydrophobic and hydrophilic monomers, possessing certain surface activity and a solubilizing effect on the hydrophobic monomers. This allows for copolymerization without the addition of surfactants, yielding high molecular weight copolymer products.

[0009] The amphiphilic block copolymer macromonomer used in this invention incorporates hydrophobic polycaprolactone (PCL) and hydrophilic polyethylene glycol (PEG) blocks, introducing amphiphilic, surface-active side chains into the copolymer. The hydrophobic PCL segments tend to bind to hydrophobic regions in the oil phase, oil films on rock surfaces, or polymer micelles, providing strong adsorption and anchoring effects; the hydrophilic PEG segments extend into the aqueous phase, providing a strong hydration layer. These amphiphilic functional side chains are covalently linked to the copolymer backbone via chemical bonds, preventing significant loss or chromatographic separation due to adsorption, unlike small-molecule surfactants. This ensures the durability and stability of the function, a significant advantage over surfactant flooding. The amphiphilic block copolymer macromonomer of this invention, by introducing amphiphilic side chains into the copolymer, can significantly improve oil recovery after waterflooding. Residual oil reservoirs after waterflooding often contain heavy crude oil with strong asphaltenes and gums that are difficult to effectively remove with conventional surfactants. The copolymer side chains of this invention, specifically the PCL segments, exhibit a strong affinity for asphaltene plaques or colloidal clusters. The polycyclic aromatic ring structure introduced by the dietherfluorene acrylate also demonstrates a strong affinity for asphaltene plaques or colloidal clusters, enabling them to firmly adsorb onto the oil-water or oil-rock interface. The PEG segments form a robust and ordered hydration protective layer on the water side, significantly reducing interfacial tension and forming a high-mechanical-strength interfacial film. Furthermore, these amphiphilic block side chains tend to be tightly packed at the interface, efficiently emulsifying thick oil films into fine, stable emulsion droplets, and utilizing the strong hydration force of the PEG chains to peel them off from the rock surface. This amphiphilic block side chain, along with the repeating unit structure introduced by the dietherfluorene acrylate, synergistically enhances the overall oil recovery. The hydrophobic ends of the PCL on the polymer chains aggregate to form physical crosslinking points. Because PCL segments are long and flexible, under formation injection conditions, the high-speed shearing action breaks down the hydrophobic physical cross-linking points, reducing viscosity and improving fluidity. Upon reaching deeper formations, the association points reform, increasing viscosity and achieving effective viscosity enhancement and flow control at depth. In high-permeability channels, the high flow rate and strong shear result in a relatively weak association network; in low-permeability layers, the slow flow rate allows for easier network formation and increased resistance. This adaptive characteristic more effectively blocks high-permeability bands, forcing subsequent fluids to divert to unaffected or low-permeability areas, achieving high oil recovery.

[0010] Furthermore, the diisocyanate is selected from at least one of toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and diphenylmethane diisocyanate; and / or, the number average molecular weight of polycaprolactone is 1000-2000; and / or, the number average molecular weight of the polyethylene glycol segment in polyethylene glycol monomethacrylate is 400-600. The molecular weights of the hydrophobic and hydrophilic segments of the macromonomers in amphiphilic block copolymers are important and need to be controlled within a reasonable range to fully realize their potential.

[0011] Furthermore, the amphiphilic block copolymer macromonomer is prepared by a method including the following steps: polycaprolactone is dissolved in an organic solvent, diisocyanate is added, the mixture is heated to react, then polyethylene glycol monomethacrylate and a polymerization inhibitor are added, the mixture is kept at a constant temperature to continue the reaction, and after the reaction is completed, post-treatment is performed to obtain the amphiphilic block copolymer macromonomer.

[0012] Furthermore, the organic solvent is selected from at least one of ethyl acetate, tetrahydrofuran, butyl acetate, acetone, and dichloromethane; the polymerization inhibitor is selected from at least one of p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 4-tert-butylcatechol, and hydroquinone, and the amount of polymerization inhibitor added is 1-3 wt% of the mass of polyethylene glycol monomethacrylate.

[0013] Furthermore, the heating reaction is carried out at 60-80°C, and the post-treatment involves adding the reaction product to 20-30 times its mass of diethyl ether at 5-10°C to produce a precipitate. The precipitate is then vacuum dried to obtain the amphiphilic block copolymer macromonomer.

[0014] Further, the unsaturated acid salt is selected from at least one of sodium 2-acrylamido-2-methylpropanesulfonate, sodium (meth)acrylate, and sodium methacrylate. The unsaturated acid salt is preferably sodium 2-acrylamido-2-methylpropanesulfonate. The inventors have discovered that using sodium 2-acrylamido-2-methylpropanesulfonate can yield copolymers with higher molecular weights. It is possible that the presence of sodium (meth)acrylate may lead to a chain transfer effect with the hydrophobic monomer; it is also possible that commercially available sodium (meth)acrylate contains polymerization inhibitors or chain transfer agents, affecting the increase in the molecular weight of the copolymer product.

[0015] Furthermore, the hydrophobic associating monomer is selected from at least one of (meth)benzyl acrylate, (meth)tetradecyl acrylate, (meth)hexadecyl acrylate, (meth)octadecyl acrylate, (meth)benzyl acrylate, N-dodecylacrylamide, N-tetradecylacrylamide, N-hexadecylacrylamide, dimethyltetradecylallylammonium chloride, dimethylhexadecylallylammonium chloride, and dimethyloctadecylallylammonium chloride. The chain length and amount of the hydrophobic monomer need to be properly controlled. If the chain length is too long or the amount is too high, the solubility of the hydrophobic monomer in the reaction system will be insufficient, resulting in the hydrophobic monomer not being completely dissolved in the reaction system and suspending or agglomerating in the form of tiny droplets. This disrupts the homogeneity of the reaction system, leading to significant differences in polymerization rate and composition in different regions, resulting in a wide molecular weight distribution and uneven composition of the generated copolymer, and unstable product performance. The principle of hydrophobic association and thickening relies on the appropriate and uniform distribution and association of hydrophobic groups in water. In this invention, the amphiphilic block copolymer macromonomer provides stable and reliable hydrophobic association sites, and the auxiliary role of the hydrophobic monomer can reduce the amount of hydrophobic monomer used.

[0016] A second objective of this invention is to provide a method for preparing the above-mentioned amphiphilic block copolymer surfactant containing surfactant functional groups, comprising the following steps: Under inert atmosphere and stirring conditions, acrylamide, hydrophobic associating monomer, amphiphilic block copolymer macromonomer, unsaturated acid, diether fluorene acrylate and water are added to a reaction vessel. After all the monomers are dissolved, sodium hydroxide is added to adjust the pH to 8-10, an initiator is added, and the temperature is raised to initiate the polymerization reaction. The product is then washed, dried and pulverized to obtain the product polymer surface agent.

[0017] Further, the unsaturated acid is selected from at least one of 2-acrylamido-2-methylpropanesulfonic acid and (meth)acrylic acid, corresponding to the monomers sodium 2-acrylamido-2-methylpropanesulfonate and sodium (meth)acrylate, respectively; the amount of water added makes the solid content of the reaction system 20-25%. A higher monomer concentration can increase the molecular weight of the product copolymer, but too high a solid content will lead to insufficient monomer solubility. Experiments have determined that a solid content of 20-25% in the reaction system is preferable. The inert atmosphere is nitrogen and / or argon. Nitrogen is introduced into the reaction system and air is removed by bubbling, and the inert gas is also kept in the air during the reaction. Reducing the oxygen content of the system is also beneficial to increasing the molecular weight of the product copolymer. Washing is done with ethanol, drying is done by vacuum drying, and pulverization is performed to a particle size of 0.2-0.5 mm.

[0018] Furthermore, the initiator is selected from redox initiation systems, water-soluble azo initiators, and water-soluble peroxide initiators, such as persulfate-sulfite initiation systems, tetramethylethylenediamine persulfate initiation systems, azobisisobutyramidine hydrochloride (V-50), and azobis[2-(2-imidazolin-2-yl)propane]dihydrochloride. The amount of initiator added is 0.5-1 wt% of the total monomer mass. The reaction temperature is controlled at 30-50℃. Initiation at low temperatures is beneficial for obtaining high molecular weight products with uniform molecular weight distribution, which is conducive to the stability of product performance.

[0019] Compared with the prior art, the present invention achieves the following beneficial effects: I. The amphiphilic block copolymer surfactant containing surfactant functional groups prepared by this invention exhibits excellent comprehensive properties, including suitable viscosity, extremely low oil-water interfacial tension, and excellent viscosity reduction rate. The copolymer surfactant of this invention can reduce residual oil saturation and improve oil displacement efficiency.

[0020] II. This invention introduces amphiphilic block copolymer macromonomers into the main chain of the copolymer, thereby increasing the viscosity of the displaced phase and reducing the oil-water viscosity ratio. Furthermore, due to the macromolecular characteristics of the polymeric surfactant, it becomes trapped in the rock, increasing the flow resistance of the displaced phase fluid in the porous medium and causing a decrease in the permeability of the aqueous phase, further reducing the oil-water mobility ratio. Because polymeric surfactant flooding significantly reduces the oil-water mobility ratio, it displaces the clustered residual oil after waterflooding, improving oil recovery. Attached Figure Description

[0021] Figure 1 These are microscope images of the emulsion formed by mixing the polymer additive prepared in Example 1 with oilfield reinjection water and simulated oil.

[0022] Figure 2 These are photographs showing the residual oil distribution after water flooding (left image) and after polymer flooding in Example 1 (right image). Detailed Implementation

[0023] All reagents used in the embodiments of this invention are commercially available. Preparation Example 1

[0024] 0.10 mol of polycaprolactone (number average molecular weight 1000) was dissolved in ethyl acetate, and 0.21 mol of toluene diisocyanate was added. The mixture was heated to 80 °C and reacted for 2 h. Then, 0.12 mol of polyethylene glycol monomethacrylate (PEG segment number average molecular weight 400) and the polymerization inhibitor 2,6-di-tert-butyl-p-cresol were added. The amount of polymerization inhibitor added was 3 wt% of the mass of polyethylene glycol monomethacrylate. The mixture was kept at the temperature and reacted for another 3 h. After the reaction was completed, the reaction product was added to 20 times its mass of 10 °C diethyl ether, which produced a large amount of precipitate. The precipitate was filtered and dried under vacuum to obtain the product, an amphiphilic block copolymer macromonomer. Preparation Example 2

[0025] 0.10 mol of polycaprolactone (number average molecular weight 2000) was dissolved in ethyl acetate, and 0.22 mol of toluene diisocyanate was added. The mixture was heated to 80 °C and reacted for 2 h. Then, 0.12 mol of polyethylene glycol monomethacrylate (PEG segment number average molecular weight 600) and the polymerization inhibitor 2,6-di-tert-butyl-p-cresol were added. The amount of polymerization inhibitor added was 2 wt% of the mass of polyethylene glycol monomethacrylate. The mixture was kept at the temperature and reacted for another 3 h. After the reaction was completed, the reaction product was added to 20 times its mass of 10 °C diethyl ether, which produced a large amount of precipitate. The precipitate was filtered and dried under vacuum to obtain the product, an amphiphilic block copolymer macromonomer. Preparation Example 3

[0026] 0.10 mol of polycaprolactone (number average molecular weight 3000) was dissolved in ethyl acetate, and 0.22 mol of toluene diisocyanate was added. The mixture was heated to 80 °C and reacted for 2 h. Then, 0.12 mol of polyethylene glycol monomethacrylate (PEG segment number average molecular weight 200) and the polymerization inhibitor 2,6-di-tert-butyl-p-cresol were added. The amount of polymerization inhibitor added was 2 wt% of the mass of polyethylene glycol monomethacrylate. The mixture was kept at the temperature and reacted for another 3 h. After the reaction was completed, the reaction product was added to 20 times its mass of 10 °C diethyl ether, which produced a large amount of precipitate. The precipitate was filtered and dried under vacuum to obtain the product, an amphiphilic block copolymer macromonomer. Example 1

[0027] 10 kg of acrylamide, 0.7 kg of dimethylhexadecylallylammonium chloride, 3 kg of the amphiphilic block copolymer macromonomer prepared in Example 1, 2 kg of 2-acrylamido-2-methylpropanesulfonic acid, 0.3 kg of diether fluorene acrylate, and 60 kg of deionized water were added to a reaction vessel. Nitrogen gas was purged for 1 hour under stirring to completely remove oxygen. After all the monomers were dissolved, 0.08 kg of azobisisobutyramidine hydrochloride initiator was added. The temperature was raised to 40°C and held at a constant temperature to initiate the polymerization reaction. The reaction was carried out for 6 hours. The product was washed with ethanol, vacuum dried, and pulverized to a particle size of 0.5 mm to obtain the product polymer surface agent. Its viscosity-average molecular weight was measured by Ubbelohde viscometer and was approximately 14.5 million.

[0028] Figure 1 These are microscopic images of an emulsion prepared in Example 1, consisting of a surface-modifying agent (1000 mg / L), oilfield reinjection water (4700 mg / mL salinity), and simulated oil mixed at an oil-to-liquid ratio of 1:4. It can be seen that an oil-in-water emulsion is formed, with oil droplets evenly distributed. Example 2

[0029] 10 kg of acrylamide, 1 kg of N-hexadecylacrylamide, 4 kg of the amphiphilic block copolymer macromonomer prepared in Example 2, 3 kg of 2-acrylamido-2-methylpropanesulfonic acid, 0.5 kg of diether fluorene acrylate, and 70 kg of deionized water were added to a reaction vessel. Nitrogen gas was purged for 1 hour under stirring to completely remove oxygen. After all the monomers were dissolved, 0.10 kg of azobisisobutyramidine hydrochloride initiator was added. The temperature was raised to 40°C and held at a constant temperature to initiate the polymerization reaction. The reaction was carried out for 6 hours. The product was washed with ethanol, vacuum dried, and pulverized to a particle size of 0.5 mm to obtain the product polymer surface agent. Its viscosity-average molecular weight was measured by Ubbelohde viscometer and was approximately 13.7 million. Example 3

[0030] 10 kg of acrylamide, 0.6 kg of benzyl methacrylate, 2 kg of the amphiphilic block copolymer macromonomer prepared in Preparation Example 3, 3 kg of 2-acrylamido-2-methylpropanesulfonic acid, 0.3 kg of diether fluorene acrylate, and 52 kg of deionized water were added to a reaction vessel. Nitrogen gas was purged for 1 hour under stirring to completely remove oxygen. After all the monomers were dissolved, 0.08 kg of azobisisobutyramidine hydrochloride initiator was added. The temperature was raised to 40°C and held at a constant temperature to initiate the polymerization reaction. The reaction was carried out for 6 hours. The product was washed with ethanol, vacuum dried, and pulverized to a particle size of 0.5 mm to obtain the product polymer surface agent. Its viscosity-average molecular weight was measured by Ubbelohde viscometer and was approximately 12.6 million. Example 4

[0031] Other conditions were the same as in Example 1, except that 2-acrylamido-2-methylpropanesulfonic acid was replaced with an equal mass of acrylic acid, the viscosity-average molecular weight of which was measured by Ubbelohde viscometer and was approximately 10.5 million. Comparative Example 1

[0032] The other conditions were the same as in Example 1, except that the macromonomer of the amphiphilic block copolymer prepared in Example 1 was replaced with an equal mass of isopentenyl polyoxyethylene ether (TPEG, number average molecular weight 3000), whose viscosity average molecular weight was approximately 12.4 million as measured by Ubbelohde viscometer. Comparative Example 2

[0033] Other conditions were the same as in Example 1, except that the dietherfluorene acrylate was replaced with 0.1 kg of methylenebisacrylamide, whose viscosity-average molecular weight was approximately 13.2 million as measured by an Ubbelohde viscometer. Application examples

[0034] The polymer surfactants used in the examples and comparative examples were prepared into 0.50 wt% solutions using oilfield reinjection water (salinity 4700 mg / mL), and their viscosity and interfacial tension were tested.

[0035] Oil displacement effect test of polymer flux: The model used in the experiment was an artificially cemented rock core, 4.5cm×4.5cm×30cm, with a core permeability of 0.1μm. 2 The experimental water was oilfield reinjection water, and the oil was simulated oil with a viscosity of 8.7 mPa·s (45℃). The oil displacement experiment was conducted at 45℃. During the waterflooding stage, the injection pressure was stabilized at 0.2 MPa. After waterflooding to a water cut of over 98%, a polymer additive was injected at a concentration of 1000 mg / L and an injection volume of 0.57 PV. As the injection time increased, the injection pressure increased from 0.2 MPa to 1.5 MPa, after which waterflooding was resumed to a water cut of over 98%. The waterflooding recovery rate of each core sample remained stable between 42.9% and 43.1%.

[0036] Figure 2These are photographs showing the residual oil distribution after water flooding (left image) and after polymer flooding in Example 1 (right image).

[0037] Table 1 Performance Tests of Polymer Surface Agents

[0038] It is evident that the amphiphilic block copolymer surfactant containing surfactant functional groups provided by this invention can effectively improve oil recovery.

Claims

1. An amphiphilic block copolymer surfactant containing surfactant functional groups, characterized in that, It is obtained by copolymerizing the following monomers in parts by weight: 100 parts by weight of acrylamide, 6-10 parts by weight of hydrophobic associating monomer, 20-40 parts by weight of amphiphilic block copolymer macromonomer, 20-30 parts by weight of unsaturated acid salt, and 3-5 parts by weight of diether fluorene acrylate; wherein the amphiphilic block copolymer macromonomer comprises the following raw materials in parts by weight: 1 part by weight of polycaprolactone, 2-2.2 parts by weight of diisocyanate, and 1.1-1.3 parts by weight of polyethylene glycol monomethacrylate.

2. The polymer surfactant according to claim 1, characterized in that, The viscosity-average molecular weight of the amphiphilic block copolymer containing surfactant functional groups is 12-15 million.

3. The polymer surfactant according to claim 1, characterized in that, The diisocyanate is selected from at least one of toluene diisocyanate, hexamethylene diisocyanate, dicyclohexylmethane diisocyanate, and diphenylmethane diisocyanate; and / or, the number average molecular weight of polycaprolactone is 1000-2000; and / or, the number average molecular weight of the polyethylene glycol segment in polyethylene glycol monomethacrylate is 400-600.

4. The polymer surfactant according to claim 1, characterized in that, The amphiphilic block copolymer macromonomer is prepared by a method including the following steps: polycaprolactone is dissolved in an organic solvent, diisocyanate is added, the mixture is heated to react, then polyethylene glycol monomethacrylate and a polymerization inhibitor are added, the mixture is kept at a constant temperature to continue the reaction, and after the reaction is completed, post-treatment is performed to obtain the amphiphilic block copolymer macromonomer.

5. The polymer surfactant according to claim 4, characterized in that, The organic solvent is selected from at least one of ethyl acetate, tetrahydrofuran, butyl acetate, acetone, and dichloromethane; the polymerization inhibitor is selected from at least one of p-hydroxyanisole, 2,6-di-tert-butyl-p-cresol, 4-tert-butylcatechol, and hydroquinone, and the amount of polymerization inhibitor added is 1-3 wt% of the mass of polyethylene glycol monomethacrylate.

6. The polymer surfactant according to claim 1, characterized in that, The unsaturated acid salt is selected from at least one of sodium 2-acrylamido-2-methylpropanesulfonate, sodium (meth)acrylate, and sodium methacrylate.

7. The polymer surfactant according to claim 1, characterized in that, The hydrophobic associating monomer is selected from at least one of (meth)benzyl acrylate, (meth)tetradecyl acrylate, (meth)hexadecyl acrylate, (meth)octadecyl acrylate, (meth)benzyl acrylate, N-dodecylacrylamide, N-tetradecylacrylamide, N-hexadecylacrylamide, dimethyltetradecylallylammonium chloride, dimethylhexadecylallylammonium chloride, and dimethyloctadecylallylammonium chloride.

8. A method for preparing the amphiphilic block copolymer surfactant containing surfactant functional groups according to any one of claims 1-7, characterized in that, Includes the following steps: Under inert atmosphere and stirring conditions, acrylamide, hydrophobic associating monomer, amphiphilic block copolymer macromonomer, unsaturated acid, diether fluorene acrylate and water are added to a reaction vessel. After all the monomers are dissolved, sodium hydroxide is added to adjust the pH to 8-10, an initiator is added, and the temperature is raised to initiate the polymerization reaction. The product is then washed, dried and pulverized to obtain the product polymer surface agent.

9. The preparation method according to claim 8, characterized in that, The unsaturated acid is selected from at least one of 2-acrylamido-2-methylpropanesulfonic acid and (meth)acrylic acid; the amount of water added makes the solid content of the reaction system 20-25%; the pulverization is to crush to a particle size of 0.2-0.5 mm.

10. The preparation method according to claim 8, characterized in that, The initiator is selected from the persulfate-sulfite initiation system, the tetramethylethylenediamine persulfate initiation system, azobisisobutyramidine hydrochloride (V-50), and azobis[2-(2-imidazolin-2-yl)propane] dihydrochloride; the amount of initiator added is 0.5-1wt% of the total mass of the monomers; the reaction temperature is controlled at 30-50℃.

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