A surface-active functional polymer, a preparation method and application thereof

Abstract

The application discloses a kind of polymers with surface active function, preparation method and application.The polymer contains structural unit A, structural unit B and structural unit C.The content of structural unit A is 60-89wt%, the content of structural unit B is 10-30wt%, and the content of structural unit C is 0.5-30wt%, with the weight of the polymer with surface active function being 100%.The preparation method includes: monomer D, monomer E and monomer F are polymerized in water in the presence of initiator to obtain the polymer with surface active function.The surface active polymer of the application can effectively solve the poor temperature resistance and inorganic high-valent cation resistance of the existing oil displacement system, and shows good surface activity.It can be used as a polymer oil displacement agent, and can be applied to high-temperature and high-salt reservoirs to further improve the recovery of crude oil in tertiary oil recovery.

Description

Technical Field

[0001] This invention relates to the field of oil extraction technology, and more specifically, to a surface-active polymer, its preparation method, and its application. Background Technology

[0002] High molecular weight partially hydrolyzed polyacrylamide (HMWPA) is a widely used polymer flooding agent in tertiary oil recovery. It exhibits good chemical stability, high viscosity retention, and high swept volume in low-temperature, low-salinity Class I and II reservoirs, thereby improving oil recovery. However, in high-temperature, high-salinity Class III reservoirs, HMWPA exhibits poor salt tolerance, is easily hydrolyzed and severely degraded, and precipitates due to complexation with calcium and magnesium ions, reducing the solution viscosity retention. This diminishes its oil displacement effect in Class III reservoirs, resulting in less economic benefit. Currently, developing oil displacement agents resistant to high-temperature and high-salinity formation conditions for Class III reservoirs (formation temperature 70-95℃, formation salinity 10000-30000 mg / L) has become a research hotspot.

[0003] In tertiary oil recovery technologies, ternary chemical composite flooding can achieve ultra-low interfacial tension between oil and water while maintaining the viscosity of the injected fluid, significantly improving oil recovery. However, the adsorption, diffusion, and migration characteristics of mixtures of different chemical agents in the porous reservoir medium vary considerably, leading to a "chromatographic separation effect" during oil displacement in the reservoir pores. Simultaneously, surfactant loss increases during displacement, reducing recovery and economic benefits. Furthermore, the use of strong alkaline additives results in severe scaling at various stages of the production process, posing challenges to production management.

[0004] To ensure that the oil displacement system maintains sufficiently high viscosity and ultra-low interfacial tension under high salinity and high temperature conditions, it is necessary to break away from the traditional framework of polymer / surfactant composite systems. By combining the thickening ability of polymers with the surface activity of low-molecular-weight surfactants, functional groups with excellent surface activity are introduced into the polymer chain, achieving both thickening and reduced interfacial tension. A single material can function as both a polymer and a surfactant. Therefore, this type of surface-active polymeric oil displacement agent can, to some extent, solve the chromatographic separation effect problem inherent in polymer-surfactant composite flooding. Furthermore, due to the thickening properties of the surface-active functional polymer, it also has a foam-stabilizing effect, acting as a foam stabilizer in foam flooding and multi-element foam composite flooding. These superior properties make it a promising candidate for application in tertiary oil recovery.

[0005] Research on surface-active functional polymers is deepening, and developing new varieties and synthetic methods is currently a research hotspot. However, due to insufficient understanding of the relationship between structure and properties, and the extreme complexity of macromolecular aqueous solutions involving physicochemical properties, research progress in this field of surface-active functional polymers has been slow to date. Therefore, studying the relationship between their structure and properties and synthesizing high-molecular-weight copolymers with good surface activity has significant theoretical and applied value.

[0006] Chinese patent CN1155555A describes a terpolymer with high molecular weight and high surface activity, produced by copolymerizing carboxymethyl cellulose, a surface-active macromonomer, and a third monomer. The terpolymer has a molecular weight of 2 × 10⁻⁶. 4 -2×10 5 The surface tension can reach 28-35 mN / m, and the interfacial tension is 0.1-3 mN / m. This copolymer has excellent interfacial activity and effectively overcomes the defect of immiscibility in the application of polymer and low molecular weight surfactant blend solutions, thus reducing costs. However, its molecular weight is relatively low, resulting in low copolymer viscosity, which cannot effectively reduce the oil-water mobility ratio and increase the swept volume to achieve the purpose of improving the recovery rate.

[0007] Chinese patent CN105331347A describes a modified PVA polyvinyl alcohol polymeric surfactant for oil displacement obtained by reacting water-soluble PVA and oil-soluble substances under certain conditions. The resulting product is both water-soluble and partially oil-soluble, thus increasing the compatibility of the surfactant solution with crude oil. However, under harsh reservoir conditions, it lacks temperature and salt resistance, as well as the ability to reduce the oil saturation of the affected reservoir. Sun Lili et al. from Southwest Petroleum Institute synthesized a novel polymeric surfactant using homogeneous polymerization. This polymeric surfactant is a terpolymer of acrylamide, acrylic acid, and methyl methacrylate. While its ability to reduce surface tension is less than that of low-molecular-weight surfactants, its synergistic effect when combined with inorganic salts produces superior performance compared to single surfactants, resulting in even lower surface tension. However, this polymeric surfactant exhibits poor temperature and salt resistance.

[0008] Therefore, developing a polymer with surface-active properties is a pressing technical problem that needs to be solved. Summary of the Invention

[0009] To address the problems in existing technologies, this invention provides a surface-active functional polymer, its preparation method, and its applications. By introducing surface-active monomers and temperature- and salt-resistant functional groups, a surface-active functional polymer with good surface activity, thickening ability in aqueous media, and high-temperature and high-salt resistance and water solubility is obtained.

[0010] One of the objectives of this invention is to provide a polymer with surface-active properties.

[0011] The polymer contains structural unit A, structural unit B and structural unit C;

[0012] The structure of structural unit A is shown in equation (1):

[0013]

[0014] The structure of structural unit B is shown in equation (2):

[0015]

[0016] n is an integer between 6 and 20;

[0017] The structure of structural unit C is shown in equation (3):

[0018]

[0019] R is selected from H, C1~C 12 Alkyl or C1-C 12 alkylaryl; R is preferably selected from C6-C 12 Alkyl or benzyl groups.

[0020] In a preferred embodiment of the present invention,

[0021] Based on the weight of the surface-active polymer as 100%,

[0022] The content of structural unit A is 60-89 wt%;

[0023] The content of structural unit B is 10-30 wt%.

[0024] The content of structural unit C is 0.5-30 wt%.

[0025] In a further preferred embodiment of the present invention,

[0026] Based on the weight of the surface-active polymer as 100%,

[0027] The content of structural unit A is 70-85 wt%;

[0028] The content of structural unit B is 10-20 wt%.

[0029] The content of structural unit C is 0.5-10 wt%.

[0030] In a preferred embodiment of the present invention,

[0031] The polymer has a viscosity-average molecular weight of 10 million to 15 million; preferably 10 million to 13 million.

[0032] The intrinsic viscosity η of the polymer is 1900-2650 mL / g, preferably 1900-2350 mL / g;

[0033] When the polymer solution concentration is 1500 mg / L, the surface tension is 33-40 mN / m, preferably 33-36 mN / m.

[0034] In a preferred embodiment of the present invention:

[0035] The structure of structural unit B is shown in equation (7), equation (8), or equation (9):

[0036]

[0037] The structure of structural unit C is shown in equation (10) or equation (11):

[0038]

[0039] The second objective of this invention is to provide a method for preparing a polymer with surface-active functions.

[0040] The method includes:

[0041] Monomers D, E, and F are polymerized in water in the presence of an initiator to obtain the surface-active polymer.

[0042] The monomer D is acrylamide;

[0043] The structure of the monomer E is shown in equation (5):

[0044]

[0045] n is an integer between 6 and 20;

[0046] The structure of the monomer F is shown in equation (6):

[0047]

[0048] R is selected from H, C1~C 12 Alkyl or C1-C 12 alkylaryl; R is preferably selected from C6-C 12 alkyl or benzyl groups;

[0049] The total weight of the monomers is 100%, and the content of monomer D is 60-89 wt%, the content of monomer E is 10-30 wt%, and the content of monomer F is 0.5-30 wt%; preferably: the content of monomer D is 70-85 wt%; the content of monomer E is 10-20 wt%; and the content of monomer F is 0.5-10 wt%.

[0050] The content of the monomer mixture is 10-30 wt%, preferably 20-30 wt%, based on the total content of the solvent and monomer mixture being 100%.

[0051] The monomer mixture mentioned above is monomer D, monomer E, and monomer F;

[0052] In a preferred embodiment of the present invention,

[0053] The polymerization temperature is 0-25℃, preferably 0-15℃;

[0054] The polymerization time is 2-15 hours; preferably 10-15 hours.

[0055] In a preferred embodiment of the present invention,

[0056] The polymerization reaction is carried out in the presence of a protective gas;

[0057] The protective gas is a gas that does not react with the raw materials and products; preferably nitrogen or argon.

[0058] In a preferred embodiment of the present invention,

[0059] The structural formula of the monomer E is:

[0060]

[0061] The structural formula of the monomer F is:

[0062]

[0063] In a preferred embodiment of the present invention,

[0064] The initiator is any two of the following: azo initiators, peroxide initiators, and redox initiators;

[0065] The amount of initiator used is 0.01-0.1 wt% of the total weight of the monomers.

[0066] In a preferred embodiment of the present invention,

[0067] The polymerization reaction is carried out at a pH of 7-10, preferably 7-9; the pH is adjusted by adding a pH adjuster to the polymerization system.

[0068] The pH adjuster is at least one of sodium hydroxide, sodium carbonate, potassium carbonate, and ammonia water.

[0069] In a preferred embodiment of the present invention,

[0070] The polymerization reaction is carried out in the presence of a chelating agent;

[0071] The chelating agent is disodium ethylenediaminetetraacetate, aminotriacetic acid, or ammonium citrate.

[0072] Based on the content of the monomer mixture, the amount of the chelating agent is 0.1-0.3 wt% of the total weight of the monomers.

[0073] In a preferred embodiment of the present invention,

[0074] The polymerization reaction is carried out in the presence of a molecular weight regulator;

[0075] The molecular weight regulator is at least one of isopropanol, ammonia, N,N'-methylenebisacrylamide, and dimethylthiourea.

[0076] The amount of the molecular weight regulator is 0.02-0.05 wt% of the total weight of the monomers.

[0077] In a preferred embodiment of the present invention,

[0078] The polymerization reaction is carried out in the presence of an auxiliary agent;

[0079] The auxiliary agent is at least one of urea, thiourea, or ammonia water;

[0080] The amount of the adjuvant is 0.01-0.1 wt% of the total weight of the monomers.

[0081] The total weight of the monomers mentioned in this invention is the sum of the weights of monomers D, E, and F.

[0082] A third objective of this invention is to provide an application of a surface-active polymer in oil extraction.

[0083] The present invention can specifically adopt the following technical solutions:

[0084] This invention provides a surface-active functional polymer, characterized in that the surface-active functional polymer contains structural unit A, structural unit B and structural unit C, wherein structural unit A is a structural unit having the structure shown in formula (1), structural unit B is a structural unit having the structure shown in formula (2), and structural unit C is a structural unit having the structure shown in formula (3); wherein, based on the weight of the surface-active functional polymer, the content of structural unit A is 60-89 wt%, the content of structural unit B is 10-30 wt%, the content of structural unit C is 0.5-30 wt%, and the viscosity-average molecular weight of the surface-active functional polymer is 10 million-15 million;

[0085]

[0086] R is selected from H, C1 to C1. 12 Alkyl or C1-C 12 Alkyl aryl; n is an integer from 6 to 20.

[0087] According to the present invention, the C1-C 12 The alkyl group can be straight-chain or branched, wherein the C1-C 12 The alkyl groups may include, but are not limited to: methyl, ethyl, n-propyl, isopropyl, n-butyl, sec-butyl, isobutyl and tert-butyl, n-pentyl, isopentyl, tert-pentyl, neopentyl, n-hexyl, n-heptyl, n-octyl, n-nonyl, n-decyl, n-undecyl and n-dodecyl.

[0088] In this invention, C1-C 12 The alkylaryl group indicates that the alkyl group that is an aryl substituent has 1-12 carbon atoms.

[0089] According to a preferred embodiment of the present invention, R is preferably selected from C6-C. 12 Alkyl or benzyl groups.

[0090] According to the present invention, in the surface-active functional polymer, based on the weight of the surface-active functional polymer, the content of structural unit A is preferably 70-85 wt%, the content of structural unit B is preferably 10-20 wt%, the content of structural unit C is preferably 0.5-10 wt%, and the viscosity-average molecular weight of the surface-active functional polymer is preferably 10 million-13 million.

[0091] According to the present invention, the intrinsic viscosity η of the polymer is preferably 1900-2650 mL / g, and the surface tension is preferably 33-40 mN / m when the polymer solution concentration is 1500 mg / L.

[0092] In this invention, the intrinsic viscosity was determined according to the method for determining the intrinsic viscosity of polyacrylamide specified in GB12005.1-89, using an Ubbelohde viscometer at 25°C for a 10% by weight NaCl solution. Surface tension was measured using a Dataphysics DCAT21 surface tension meter.

[0093] According to the present invention, the intrinsic viscosity η of the polymer is further preferably 1900-2350 mL / g, and when the polymer solution concentration is 1500 mg / L, its surface tension is further preferably 33-36 mN / m.

[0094] The inventors of this invention discovered in their research that polymers composed of specific structural units A, B, and C can achieve good oil displacement effects when used as oil displacement agents. For example, structural unit A is a unit having the structure shown in formula (1), structural unit B can be one of the units having the structure shown in formula (7), formula (8), or formula (9), and structural unit C can be one of the units having the structure shown in formula (10) or (11).

[0095]

[0096] The present invention also provides a method for preparing a surface-active polymer, the method comprising, under solution polymerization conditions, in the presence of an initiator and a solvent, polymerizing a monomer mixture in water, the monomer mixture containing monomer D, monomer E and monomer F; wherein monomer D is a monomer having the structure shown in formula (4), monomer E is a monomer having the structure shown in formula (5), and monomer F is a monomer having the structure shown in formula (6); and based on the total amount of the monomer mixture, the content of monomer D is 60-89 wt%, the content of monomer E is 10-30 wt%, and the content of monomer F is 0.5-30 wt%; the polymerization conditions are such that the viscosity-average molecular weight of the polymer obtained after the polymerization reaction is 10 million-15 million;

[0097]

[0098] R is selected from H, C1 to C1. 12 Alkyl or C1-C 12 Alkyl aryl; n is an integer from 6 to 20.

[0099] According to the present invention, R is preferably selected from C6-C. 12 Alkyl or benzyl groups.

[0100] The inventors of this invention discovered in their research that polymers obtained by reacting specific monomers D, E, and F can achieve good oil displacement effects when used as oil displacement agents. For example, monomer D can be a monomer having the structure shown in formula (4), monomer E can be at least one of monomers having the structures shown in formulas (7), (8), and (9), and monomer F can be at least one of monomers having the structures shown in formulas (10) and (11).

[0101]

[0102]

[0103] According to the method of the present invention, the polymerization reaction is carried out in the presence of an inert gas, and the polymerization reaction conditions include: a polymerization temperature of 0-25°C, preferably 0-15°C; and a polymerization time of 2-15 hours, preferably 10-15 hours. The inert gas is a gas that does not react with the raw materials and products, and can be nitrogen or at least one of the group 0 elements in the periodic table, preferably nitrogen and argon.

[0104] According to the method of the present invention, the polymerization reaction is preferably carried out at a pH of 7-10, more preferably 7-9. The above pH value can be obtained by adding a pH adjuster to the polymerization system. The pH adjuster used to adjust the pH value can be any of the pH adjusters commonly used in the art, such as at least one of sodium hydroxide, sodium carbonate, potassium carbonate, and ammonia water, preferably sodium hydroxide.

[0105] According to the method of the present invention, the content of the monomer mixture is not particularly limited and can vary within a wide range. Based on the total content of the solvent and the monomer mixture, the content of the monomer mixture is 15-30 wt%, preferably 20-30 wt%.

[0106] According to the method of the present invention, the amount of the initiator is not particularly limited and can vary within a wide range. Based on the content of the monomer mixture, the amount of the initiator is 0.01-0.1 wt%.

[0107] According to the method of the present invention, the initiator can be any of the various initiators commonly used in the art, for example, any two selected from free radical polymerization initiators; the free radical polymerization initiators include azo initiators, peroxide initiators, and redox initiators; the azo initiator is selected from at least one of dimethyl azobisisobutyrate, azobisisobutyramidine hydrochloride, azodicarbonamide, azobisisopropylimidazoline hydrochloride, azoisobutylcyanoformamide, azodicyclohexylformonitrile, azobiscyanopentanoic acid, azobisisopropylimidazoline, azobisisobutyronitrile, azobisisovalerate, and azobisisoheptanenitrile; the peroxide initiator is selected from at least one of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, benzoyl peroxide, and benzoyl tert-butyl peroxide; the redox initiator is selected from at least one of sulfate-sulfite, persulfate-thiourea, persulfate-organic salt, and ammonium persulfate-aliphatic amine.

[0108] According to the method of the present invention, the addition of a chelating agent can prevent the influence of metal ions on the polymerization reaction; therefore, preferably, the polymerization reaction is carried out in the presence of a chelating agent. The chelating agent can be disodium ethylenediaminetetraacetate, aminotriacetic acid, or ammonium citrate, preferably disodium ethylenediaminetetraacetate. Based on the content of the monomer mixture, the amount of the chelating agent can be 0.1-0.3 wt%.

[0109] According to the method of the present invention, the addition of an auxiliary agent can improve the solubility of the copolymer; therefore, preferably, the polymerization reaction is carried out in the presence of the auxiliary agent. The auxiliary agent can be substances such as urea, thiourea, or ammonia, preferably urea. Based on the content of the monomer mixture, the amount of the auxiliary agent can be 0.01-0.1 wt%.

[0110] According to the method of the present invention, polymers of different molecular weights can be synthesized by adding a molecular weight regulator; therefore, preferably, the polymerization reaction is carried out in the presence of a molecular weight regulator. The molecular weight regulator may be at least one selected from isopropanol, ammonia, N,N'-methylenebisacrylamide, and dimethylthiourea.

[0111] In a preferred embodiment, the method of the present invention further includes purifying and drying the polymerized mixture to obtain a purified polymer. The purification is preferably performed using acetone for precipitation purification.

[0112] The present invention also provides a surface-active functional polymer prepared by the above method.

[0113] This invention, from a molecular design perspective, introduces surface-active functional monomers E and F into the macromolecular structure of polyacrylamide. This provides surface activity to the polymer and improves the temperature and salt resistance of the polymer product. The active carbon-carbon double bonds in the molecular structures of monomers E and F give them high reactivity, readily copolymerizing with various other olefin monomers to form different functional polymers. The polyether structure in monomer E provides good hydrophilicity and surface activity, while also exhibiting resistance to acids, alkalis, and hard water. Monomer F contains the strongly cationic and hydrophilic quaternary ammonium ion functional group, as well as sulfonate groups and long side-chain alkyl groups, providing excellent surfactant properties, resistance to cationic precipitation, and temperature resistance. The surface-active functional polymer described in this invention combines the thickening properties of high molecular weight polymers with the surface activity of low molecular weight surfactants, offering advantages such as easy flow control and reduced oil / water interfacial tension. This, to a certain extent, solves problems such as chromatographic separation effects associated with polymer-surfactant composite flooding. The surface-active polymers of this invention have high viscosity-average molecular weights. In the examples, the polymers obtained all have viscosity-average molecular weights exceeding 10 million. They were prepared into a 1500 mg / L aqueous solution using a saline solution with a mineralization of 15000 mg / L, and subjected to a shear rate of 7.34 s⁻¹. -1 At 25℃, its apparent viscosity can reach 49.3 mPa·s, and when the temperature is raised to 80℃, the viscosity is still 12.6-18.3 mPa·s. When prepared into a 1500 mg / L aqueous solution using brine with a mineralization of 25000 mg / L, at a shear rate of 7.34 s⁻¹... -1 At a temperature of 25°C, its apparent viscosity can reach 26.5 mPa·s, and when the temperature is raised to 80°C, the viscosity is still 10.8-14.3 mPa·s. This indicates that the surface-active functional polymer of the present invention can effectively solve the problems of poor temperature resistance and resistance to inorganic high-valence cations in the existing oil displacement system. At the same time, the surface tension of the polymer aqueous solution is between 33 mN / m and 40 mN / m, showing good surface activity.

[0114] Therefore, the surface-active polymer of the present invention can be used as a polymer flooding agent, and is suitable for high-temperature and high-salinity oil reservoirs, further improving crude oil recovery rate in tertiary oil recovery. Detailed Implementation

[0115] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0116] The present invention will now be described in detail with reference to the embodiments, but the scope of the present invention is not limited to these embodiments.

[0117] The testing method involved in this invention is as follows:

[0118] The dissolution time of the polymer was determined according to the method specified in GB12005.8-89.

[0119] The intrinsic viscosity η of the polymer was determined according to the method for determining the intrinsic viscosity of polyacrylamide specified in GB12005.1-89, using an Ubbelohde viscometer at 25°C for a 10% by weight NaCl solution.

[0120] The viscosity-average molecular weight is calculated using the formula M = (η / K). 1\α The calculation yields K = 4.5 × 10⁻⁶. -3 , α=0.80.

[0121] The apparent viscosity of the polymer solution was measured using a Brookfield DV-III viscometer, with a constant shear rate of 7.34 s⁻¹. -1 .

[0122] Surface tension was measured according to the method specified in GB / T 22237-2008 using a Dataphysics DCAT21 surface tension meter.

[0123] The solid content was determined according to the determination method of GB12005.2-89.

[0124] Molecular structural formulas and the composition of structural units are quantitatively analyzed. 13 C-spectrum determination.

[0125] All reagents used in the examples were commercially available chemically pure reagents;

[0126] The polymer sample KYP used in the comparative example was an in-use sample provided by the oilfield. KYP contains acrylamide structural units and 2-methyl-2-acrylamidopropanesulfonic acid structural units. Based on the weight of KYP, the content of acrylamide structural units is 75% by weight, and the content of 2-methyl-2-acrylamidopropanesulfonic acid structural units is 25% by weight. KYP has a viscosity-average molecular weight of 10.1 million and an intrinsic viscosity of 1915 mL / g.

[0127] Monomer F1 was prepared according to the method described in the literature Maleic diamide polymerizable surfactants. Applications in emulsion polymerization. Comptes Rendus Chimie, 2003, 6(11-12):1295-1304, and its structure is shown in formula (10):

[0128]

[0129] Monomer F2 was prepared according to the method described in the literature Maleic diamide polymerizable surfactants. Applications in emulsion polymerization. Comptes Rendus Chimie, 2003, 6(11-12):1295-1304, and its structural formula is shown in formula (11):

[0130]

[0131] Example 1

[0132] An aqueous solution polymerization method was used. 15.0 g of monomer F1 as a water-soluble surfactant, 90.0 g of acrylamide, and 45.0 g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2)6OOCCH=CHCH3) and distilled water were added, with the total monomer content being 10wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became transparent. Then, 60mg of urea, 200mg of disodium ethylenediaminetetraacetate, 3mL of ammonia, and 80mg of isopropanol were added. Simultaneously, the pH of the system was adjusted to 10.0 with sodium hydroxide, and the initial temperature of the system was controlled at 25℃. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 50mg of ammonium persulfate and 25mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was purged for another 10 minutes. The reactor was sealed, and the reaction was carried out for 2 hours to obtain a transparent, viscous polymer. The gel-like product was removed, granulated, dried, pulverized, and sieved to obtain the high molecular weight surface-active functional polymer product P1.

[0133] Performance determination of polymer P1: Quantitative analysis 13 In the C-ray diffraction spectrum, C=O and CH2-N from equation (19) appeared at 177.53 ppm, 63.96 ppm, 40.73 ppm, and 72.21 ppm, respectively. + The characteristic peaks of the CONH-C and COC bonds were observed, and the characteristic peak of carbon propanesulfonic acid appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which confirmed that the obtained copolymer molecule had the structure shown in formula (19). The x1:y1:z1 ratio could be calculated to be 1:0.016:0.03 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P1 was 1556 mL / g, and the viscosity-average molecular weight was 785 × 10⁻⁶. 4When the polymer solution concentration was 1500 mg / L, the surface tension was 33.3 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P1 solution at different temperatures and salinities under the specified conditions. Here, salinity refers to the Na+ content in simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0134]

[0135] Example 2

[0136] An aqueous solution polymerization method was used, in which 30.0 g of monomer F1 as a water-soluble surfactant monomer, 210.0 g of acrylamide, and 60.0 g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2) 16 OOCCH=CHCH3) and distilled water were added, with the total content of monomer and distilled water as the basis, and the total monomer content as 20wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became a transparent solution. Then, 120mg of urea, 360mg of disodium ethylenediaminetetraacetate, 5mL of ammonia water and 150mg of isopropanol were added. At the same time, the pH of the system was adjusted to 9.0 with sodium hydroxide, and the initial temperature of the system was controlled at 15℃. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 100mg of ammonium persulfate and 50mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was purged for another 10 minutes. The reactor was sealed and the reaction was carried out for 10 hours to obtain a transparent, viscous polymer. The gel-like product was taken out, granulated, dried, pulverized and sieved to obtain the high molecular weight surface-active functional polymer product P2.

[0137] Performance determination of polymer P2: Quantitative analysis 13 In the C-ray diffraction (C-N) spectrum, C=O and CH2-N from equation (20) appeared at 177.53 ppm, 63.96 ppm, 40.73 ppm, and 72.21 ppm, respectively. +The characteristic peaks of the CONH-C and COC bonds were observed, and the characteristic peak of carbon propanesulfonic acid appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which confirmed that the obtained copolymer molecule had the structure shown in formula (20). The x1:y1:z1 ratio could be calculated to be 1:0.023:0.017 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P2 was 1906 mL / g, and the viscosity-average molecular weight was 1013 × 10⁻⁶. 4 When the polymer solution concentration was 1500 mg / L, the surface tension was 33.1 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P2 solution at different temperatures and salinities under the specified conditions. Here, salinity refers to the Na+ content in simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0138] Example 3

[0139] An aqueous solution polymerization method was used. 30g of monomer F1 (as a water-soluble surfactant monomer), 281.25g of acrylamide, and 63.75g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2) 16 OOCCH=CHCH3) and distilled water were added, with the total content of monomer and distilled water as the basis, and the total monomer content as 25wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became a transparent solution. Then, 120mg of urea, 400mg of disodium ethylenediaminetetraacetate, 5mL of ammonia water and 120mg of isopropanol were added. At the same time, the pH of the system was adjusted to 8.0 with sodium hydroxide, and the initial temperature of the system was controlled at 8°C. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 60mg of ammonium persulfate and 30mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was purged for another 10 minutes. The reactor was sealed and the reaction was carried out for 12 hours to obtain a transparent, viscous polymer. The gel-like product was taken out, granulated, dried, pulverized and sieved to obtain the high molecular weight surface-active functional polymer product P3.

[0140] Performance determination of polymer P3: quantitative analysis 13In the C-ray diffraction (C-N) spectrum, C=O and CH2-N from equation (20) appeared at 177.53 ppm, 63.96 ppm, 40.73 ppm, and 72.21 ppm, respectively. + The characteristic peaks of the CONH-C and COC bonds were observed, and the characteristic peak of carbon propanesulfonic acid appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which confirmed that the obtained copolymer molecule had the structure shown in formula (20). The x1:y1:z1 ratio could be calculated to be 1:0.017:0.016 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P3 was 1975 mL / g, and the viscosity-average molecular weight was 1095 × 10⁻⁶. 4 When the polymer solution concentration was 1500 mg / L, the surface tension was 34.5 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P3 solution at different temperatures and salinities under the specified conditions. Here, salinity refers to the Na+ content in simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0141] Example 4

[0142] An aqueous solution polymerization method was used. 18.75 g of monomer F1 as a water-soluble surfactant, 281.25 g of acrylamide, and 75.0 g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2) 16OOCCH=CHCH3) and distilled water were added, with the total content of monomer and distilled water as the basis. The total monomer content was 25wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became a transparent solution. Then, 100mg of urea, 300mg of disodium ethylenediaminetetraacetate, 10mL of ammonia water and 150mg of isopropanol were added. At the same time, the pH of the system was adjusted to 7.0 with sodium hydroxide, and the initial temperature of the system was controlled at 5°C. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 100mg of ammonium persulfate and 50mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was purged for another 10 minutes. The reactor was sealed and the reaction was carried out for 12 hours to obtain a transparent, viscous polymer. The gel-like product was taken out, granulated, dried, pulverized and sieved to obtain the high molecular weight surface-active functional polymer product P4.

[0143] Performance determination of polymer P4: Quantitative analysis 13 In the C-ray diffraction (C-N) spectrum, C=O and CH2-N from equation (20) appeared at 177.53 ppm, 63.96 ppm, 40.73 ppm, and 72.21 ppm, respectively. + The characteristic peaks of the CONH-C and COC bonds were observed, and the characteristic peak of carbon propanesulfonic acid appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which confirmed that the obtained copolymer molecule had the structure shown in formula (20). The x1:y1:z1 ratio could be calculated to be 1:0.02:0.01 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P4 was 2089 mL / g, and the viscosity-average molecular weight was 1136 × 10⁻⁶. 4 When the polymer solution concentration was 1500 mg / L, the surface tension was 33.6 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P4 solution at different temperatures and salinities under the specified conditions. Here, salinity refers to the Na+ content in simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0144]

[0145] Example 5

[0146] An aqueous solution polymerization method was used. 18.75 g of monomer F2 as a water-soluble surfactant, 300.0 g of acrylamide, and 56.25 g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2) 16 OOCCH=CHCH3) and distilled water were added, with the total content of monomer and distilled water as the basis. The total monomer content was 25wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became a transparent solution. Then, 150mg of urea, 400mg of disodium ethylenediaminetetraacetate, 5mL of ammonia water and 150mg of isopropanol were added. At the same time, the pH of the system was adjusted to 8.0 with sodium hydroxide, and the initial temperature of the system was controlled at 2°C. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 60mg of ammonium persulfate and 30mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was purged for another 10 minutes. The reactor was sealed and the reaction was carried out for 12 hours to obtain a transparent, viscous polymer. The gel-like product was taken out, granulated, dried, pulverized and sieved to obtain the high molecular weight surface-active functional polymer product P5.

[0147] Performance determination of polymer P5: Quantitative analysis 13 In the C-ray diffraction spectrum, C=O, C6H6, COC, and CH2-N from equation (21) appeared at 177.53ppm, 128.75ppm, 72.21ppm, 63.96ppm, and 40.73ppm, respectively. + The characteristic peaks of the CONH-C bond and the characteristic peaks of propanesulfonic acid carbon appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which confirmed that the obtained copolymer molecule had the structure shown in formula (21). The x1:y1:z1 ratio could be calculated to be 1:0.01:0.01 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P5 was 2201 mL / g, and the viscosity-average molecular weight was 1196 × 10⁻⁶. 4 When the polymer solution concentration was 1500 mg / L, the surface tension was 34.8 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P5 solution at different temperatures and salinities under the specified conditions. Here, salinity refers to the Na+ content in simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO32- The sum of the contents of inorganic ions, etc.

[0148] Example 6

[0149] An aqueous solution polymerization method was used. 7.5 g of monomer F2 as a water-soluble surfactant, 300.0 g of acrylamide, and 67.5 g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2) 16 OOCCH=CHCH3) and distilled water were added, with the total monomer content being 25wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became transparent. Then, 120mg of urea, 360mg of disodium ethylenediaminetetraacetate, 5mL of ammonia, and 150mg of isopropanol were added. Simultaneously, the pH of the system was adjusted to 7.0 with sodium hydroxide, and the initial temperature of the system was controlled at 2°C. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 100mg of ammonium persulfate and 50mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was purged for another 10 minutes. The reactor was sealed, and the reaction was carried out for 15 hours to obtain a transparent, viscous polymer. The gel-like product was removed, granulated, dried, pulverized, and sieved to obtain the high molecular weight surface-active functional polymer product P6.

[0150] Performance determination of polymer P6: quantitative analysis 13 In the C-ray diffraction spectrum, C=O, C6H6, COC, and CH2-N from equation (21) appeared at 177.53ppm, 128.75ppm, 72.21ppm, 63.96ppm, and 40.73ppm, respectively. + The characteristic peaks of the CONH-C bond and the characteristic peaks of propanesulfonic acid carbon appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which confirmed that the obtained copolymer molecule had the structure shown in formula (21). The x1:y1:z1 ratio could be calculated to be 1:0.02:0.01 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P6 was 2278 mL / g, and the viscosity-average molecular weight was 1233 × 10⁻⁶. 4 When the polymer solution concentration was 1500 mg / L, the surface tension was 35.0 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P6 solution at different temperatures and salinities under the conditions described. Here, salinity refers to the Na+ content in simulated formation water. + K+ Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0151] Example 7

[0152] An aqueous solution polymerization method was used. 1.875 g of monomer F2 as a water-soluble surfactant, 318.75 g of acrylamide, and 54.375 g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2) 16 OOCCH=CHCH3) and distilled water were added, with the total content of monomer and distilled water as the basis. The total monomer content was 25wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became a transparent solution. Then, 120mg of urea, 480mg of disodium ethylenediaminetetraacetate, 5mL of ammonia water and 150mg of isopropanol were added. At the same time, the pH of the system was adjusted to 8.0 with sodium hydroxide, and the initial temperature of the system was controlled at 0℃. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 60mg of ammonium persulfate and 30mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was purged for another 10 minutes. The reactor was sealed and the reaction was carried out for 15 hours to obtain a transparent, viscous polymer. The gel-like product was taken out, granulated, dried, pulverized and sieved to obtain the high molecular weight surface-active functional polymer product P7.

[0153] Performance determination of polymer P7: quantitative analysis 13 In the C-ray diffraction spectrum, C=O, C6H6, COC, and CH2-N from equation (21) appeared at 177.53ppm, 128.75ppm, 72.21ppm, 63.96ppm, and 40.73ppm, respectively. + The characteristic peaks of the CONH-C bond and the characteristic peaks of propanesulfonic acid carbon appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which confirmed that the obtained copolymer molecule had the structure shown in formula (21). The x1:y1:z1 ratio could be calculated as 1:0.015:0.006 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P7 was 2315 mL / g, and the viscosity-average molecular weight was 1289 × 10⁻⁶. 4When the polymer solution concentration was 1500 mg / L, the surface tension was 35.9 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P7 solution at different temperatures and salinities under the conditions described. Here, salinity refers to the Na+ content in simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0154]

[0155] Example 8

[0156] An aqueous solution polymerization method was used. 4.5 g of monomer F2 as a water-soluble surfactant, 400.5 g of acrylamide, and 45.0 g of dodecyl alcohol polyoxyethylene ether methacrylate (C) were added to the polymerization reaction flask. 12 H 25 (OCH2CH2) 20 OOCCH=CHCH3) and distilled water were added, with the total content of monomer and distilled water as the basis, and the total monomer content as 30wt%. The mixture was stirred thoroughly until the solution in the polymerization flask became a transparent solution. Then, 120mg of urea, 480mg of disodium ethylenediaminetetraacetate, 5mL of ammonia water and 150mg of isopropanol were added. At the same time, the pH of the system was adjusted to 8.0 with sodium hydroxide, and the initial temperature of the system was controlled at 0℃. High-purity nitrogen gas with a volume concentration of 99.99% was purged for 30 minutes to remove oxygen from the polymerization flask. Then, 60mg of ammonium persulfate and 30mg of sodium bisulfite were added sequentially, and high-purity argon gas was purged for another 10 minutes. The reactor was sealed and the reaction was carried out for 15 hours to obtain a transparent, viscous polymer. The gel-like product was taken out, granulated, dried, pulverized and sieved to obtain the high molecular weight surface-active functional polymer product P8.

[0157] Performance determination of polymer P8: quantitative analysis 13 In the C spectrum, C=O, C6H6, COC, and CH2-N from equation (22) appeared at 177.53ppm, 128.75ppm, 72.21ppm, 63.96ppm, and 40.73ppm, respectively. +The characteristic peaks of the CONH-C bond and the characteristic peaks of propanesulfonic acid carbon appeared in the range of 50.60-56.77 ppm. At the same time, the characteristic peaks of -CH-CH2- and C=O on the main chain were superimposed, which can confirm that the obtained copolymer molecule has the structure shown in formula (22). The x1:y1:z1 ratio can be calculated as 1:0.015:0.01 by the integral area of ​​the characteristic peaks. The intrinsic viscosity of polymer P8 is 2641 mL / g and the viscosity-average molecular weight is 1513 × 10⁻⁶. 4 When the polymer solution concentration was 1500 mg / L, the surface tension was 49.8 mN / m. Polymer solutions were prepared using simulated formation water with oilfield salinity of 5000 mg / L, 15000 mg / L, and 25000 mg / L, respectively. At a polymer solution concentration of 1500 mg / L and a shear rate of 7.34 s⁻¹, the surface tension was... -1 Table 1 shows the apparent viscosity of polymer P8 solution at different temperatures and salinities under the specified conditions. Here, salinity refers to the Na+ content in simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0158]

[0159] Comparative Example 1

[0160] The performance of the comparative sample KYP (provided by the oilfield) was compared with that of the product obtained in the examples, and the results are shown in Table 1. Table 1 also shows the apparent viscosity of the polymer aqueous solution at different temperatures and mineralization levels. The apparent viscosity of the polymer aqueous solution at a concentration of 1500 mg / L at 25°C and 80°C is given.

[0161] Table 1. Apparent viscosity of surface-active functional polymers at different temperatures and mineralization degrees.

[0162]

[0163] Note: The polymer aqueous solution concentration was 1500 mg / L, and the shear rate during the test was 7.34 s. -1 .

[0164] As shown in Table 1, the aqueous solution of the acrylamide polymer (code-named KYP) provided by the oilfield exhibits high apparent viscosity at low temperatures and low salinity, but the apparent viscosity decreases significantly with increasing temperature and salinity. The polymer of this invention exhibits high apparent viscosity at low temperatures. At 80°C and a salinity of 15000 mg / L, the apparent viscosity of the polymer aqueous solution reaches 12.6-18.3 mPa·s. Even at a salinity of 25000 mg / L, it still maintains high apparent viscosity, reaching 10.8-14.3 mPa·s. This indicates that the surface-active polymer according to this invention possesses excellent temperature and salt resistance.

[0165] Comparative Example 2

[0166] The performance of the comparative sample KYP (provided by the oilfield) was compared with that of the product obtained in the examples. The surface tension of polymer aqueous solutions of different concentrations prepared with simulated formation water with a salinity of 10000 mg / L at 30°C was observed. The results are shown in Table 2.

[0167] Table 2 Surface tension of surface-active functional polymer aqueous solutions at different concentrations

[0168] 100mg / L 500mg / L 1000mg / L 1500mg / L 2000mg / L 2500mg / L Example 1 64.6 56.1 45.8 33.3 32.9 32.2 Example 2 64.9 55.9 45.3 33.1 32.6 32.3 Example 3 65.3 56.7 46.1 34.5 33.8 33.5 Example 4 64.2 55.6 43.3 33.6 32.1 32.3 Example 5 65.8 56.6 44.9 34.8 33.7 33.9 Example 6 63.8 54.9 45.3 35.0 34.9 35.1 Example 7 64.1 55.0 46.0 35.9 35.3 36.0 Example 8 67.9 65.7 58.6 49.8 48.5 48.3 KYP 68.9 67.3 65.1 62.9 63.1 63.3

[0169] Note: Polymer aqueous solutions of different concentrations were prepared using saline solution with a mineralization of 15000 mg / L, and their surface tension was measured at 25°C.

[0170] As shown in Table 2, the surface tension of the polymer aqueous solution according to the present invention gradually decreases with increasing concentration, and the decrease is significant. At a concentration of 1500 mg / L, the surface tension of the polymer aqueous solution is between 33 and 36 N / m, exhibiting good surface activity. In contrast, the surface tension of the KYP aqueous solution decreases with increasing concentration, but the decrease is small, and the surface tension is between 60 and 70 mN / m.

[0171] Table 2 shows that, compared to KYP samples used in oilfields, the aqueous solutions of the samples in this invention patent exhibit superior surface activity at different concentrations. For surface-active polymers, this superior surface activity enables them to reduce the interfacial tension between oil and water, thereby achieving oil-water separation and improving oil displacement efficiency.

[0172] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the protection scope of the present invention.

[0173] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the present invention will not describe the various possible combinations separately.

[0174] Furthermore, various different embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed by the present invention.

Claims

1. A polymer with surface-active properties, characterized in that: The polymer is composed of structural unit A, structural unit B and structural unit C; The structure of structural unit A is shown in equation (1): （1） The structure of structural unit B is shown in equation (2): （2） n is an integer between 6 and 20; The structure of structural unit C is shown in equation (3): （3） R is selected from C6-C 12 alkyl or benzyl groups; Based on the weight of the surface-active polymer as 100%, The content of structural unit A is 60-89 wt%; The content of structural unit B is 10-30 wt%; The content of structural unit C is 0.5-30wt%.

2. The surface-active polymer as described in claim 1, characterized in that: Based on the weight of the surface-active polymer as 100%, The content of structural unit A is 70-85 wt%; The content of structural unit B is 10-20 wt%; The content of structural unit C is 0.5-10 wt%.

3. The surface-active polymer as described in claim 1, characterized in that: The polymer has a viscosity-average molecular weight of 10 million to 15 million; and / or, The intrinsic viscosity η of the polymer is 1900-2650 mL / g; and / or, When the polymer solution concentration is 1500 mg / L, the surface tension is 33-40 mN / m.

4. The surface-active polymer as described in claim 3, characterized in that: The polymer has a viscosity-average molecular weight of 10 million to 13 million; and / or, The intrinsic viscosity η of the polymer is 1900-2350 mL / g; and / or, When the polymer solution concentration is 1500 mg / L, the surface tension is 33-36 mN / m.

5. The surface-active polymer as described in any one of claims 1 to 4, characterized in that: The structure of structural unit B is shown in equation (7), equation (8), or equation (9): （7） （8） （9） The structure of structural unit C is shown in equation (10) or equation (11): （10） （11）。 6. A method for preparing a surface-active polymer as described in any one of claims 1 to 5, characterized in that... The method includes: Monomers D, E, and F are polymerized in water in the presence of an initiator to obtain the surface-active polymer. The monomer D is acrylamide; The structure of the monomer E is shown in equation (5): （5） n is an integer between 6 and 20; The structure of the monomer F is shown in equation (6): （6）； R is selected from C6-C 12 alkyl or benzyl groups; The total weight of the monomers is 100%, with monomer D accounting for 60-89 wt%, monomer E accounting for 10-30 wt%, and monomer F accounting for 0.5-30 wt%. The content of the monomer mixture is 10-30 wt%, based on a total content of 100 wt% for the solvent and monomer mixture.

7. The preparation method according to claim 6, characterized in that: The total weight of the monomers is 100%, with monomer D comprising 70-85 wt%; monomer E comprising 10-20 wt%; and monomer F comprising 0.5-10 wt%. The content of the monomer mixture is 20-30 wt%, based on a total content of 100 wt% for the solvent and monomer mixture.

8. The preparation method according to claim 6, characterized in that: The polymerization temperature is 0-25℃; The polymerization time is 2-15 hours.

9. The preparation method according to claim 8, characterized in that: The polymerization temperature is 0-15℃; The aggregation time is 10-15 hours.

10. The preparation method according to claim 6, characterized in that: The polymerization reaction is carried out in the presence of a protective gas; The protective gas is a gas that does not react with the raw materials and products.

11. The preparation method according to claim 10, characterized in that: The protective gas is nitrogen or argon.

12. The preparation method according to claim 6, characterized in that: The structural formula of the monomer E is: or or ; The structural formula of the monomer F is: or .

13. The preparation method according to claim 6, characterized in that: The initiator is any two of the following: azo initiators, peroxide initiators, and redox initiators; The amount of initiator used is 0.01-0.1 wt% of the total weight of the monomers.

14. The preparation method according to claim 6, characterized in that: The polymerization reaction is carried out at a pH of 7-10; the pH is adjusted by adding a pH adjuster to the polymerization system. The pH adjuster is at least one of sodium hydroxide, sodium carbonate, potassium carbonate, and ammonia water.

15. The preparation method according to claim 14, characterized in that: The polymerization reaction is carried out under conditions of pH 7-9.

16. The preparation method according to claim 6, characterized in that: The polymerization reaction is carried out in the presence of a chelating agent; The chelating agent is disodium ethylenediaminetetraacetate, aminotriacetic acid, or ammonium citrate. The amount of the chelating agent is 0.1-0.3 wt% of the total weight of the monomers.

17. The preparation method according to claim 6, characterized in that: The polymerization reaction is carried out in the presence of a molecular weight regulator; The molecular weight regulator is at least one of isopropanol, ammonia, N,N'-methylenebisacrylamide, and dimethylthiourea. The amount of the molecular weight regulator is 0.02-0.05 wt% of the total weight of the monomer.

18. The preparation method according to claim 6, characterized in that: The polymerization reaction is carried out in the presence of an auxiliary agent; The auxiliary agent is at least one of urea, thiourea, and ammonia water; The amount of the adjuvant is 0.01-0.1 wt% of the total weight of the monomers.

19. The application of a surface-active functional polymer as described in any one of claims 1 to 5 in oil extraction.

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