Polymer as well as preparation method and application thereof

Abstract

The invention relates to the field of polymer preparation, and discloses a polymer as well as a preparation method and application thereof. The polymer contains a structural unit A, a structural unit B and a structural unit C, the structural unit A is selected from at least one of the structural units B, and the structural unit C is selected from at least one of the structural units C; wherein R1 and R2 are respectively alkyl, R3 is C10-C17 alkyl, n is an integer of 7-20, p is an integer of 2-6, and M is an alkali metal element.

Description

Technical Field

[0001] This invention relates to the field of polymer preparation, and more specifically, to a 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] CN1155555A describes a high-molecular-weight, high-surface-activity terpolymer synthesized by copolymerizing carboxymethyl cellulose, a surfactant macromonomer, and a third monomer. The copolymer has a molecular weight of 20,000-200,000, a surface tension of 28-35 mN / m, and an interfacial tension of 0.1-3 mN / m. This copolymer exhibits excellent interfacial activity and effectively overcomes the immiscibility of polymers blended with low-molecular-weight surfactants in applications, reducing costs. However, its low molecular weight results in low viscosity, which cannot effectively reduce the oil-water mobility ratio or increase the swept volume to improve oil recovery. CN105331347A describes a modified PVA polyvinyl alcohol high-molecular-weight 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.

[0007] Therefore, there is an urgent need for a surface-active functional polymer that combines good surface activity, thickening ability in water media, and high temperature and high salt resistance with water solubility. Summary of the Invention

[0008] The purpose of this invention is to overcome the problem that existing polymers are difficult to simultaneously possess good surface activity and thickening ability, and have poor temperature and salt resistance. This invention provides a polymer, its preparation method, and its application. The polymer incorporates surface-active monomers and temperature- and salt-resistant functional groups, and simultaneously possesses good surface activity and thickening ability in water media, as well as good temperature and salt resistance.

[0009] To achieve the above objectives, a first aspect of the present invention provides a polymer, wherein the polymer contains structural unit A, structural unit B, and structural unit C; structural unit A is... Structural unit B is selected from At least one of them, the structural unit C is selected from At least one of them;

[0010] Wherein, R1 and R2 are alkyl groups, and R3 is a C group. 10 -C 17Alkyl groups, n is an integer from 7 to 20, p is an integer from 2 to 6, and M is an alkali metal element.

[0011] A second aspect of the present invention provides a method for preparing a polymer, wherein the method comprises the following steps: polymerizing monomers in the presence of an initiator and a solvent, wherein the polymerizing monomers include monomer D, monomer E, and monomer F; monomer D is... Monomer E is selected from At least one of them, monomer F is selected from At least one of them;

[0012] Wherein, R1 and R2 are alkyl groups, and R3 is a C group. 10 -C 17 Alkyl groups, n is an integer from 7 to 20, p is an integer from 2 to 6, and M is an alkali metal element.

[0013] A third aspect of the present invention provides a polymer prepared by the preparation method provided by the present invention.

[0014] The fourth aspect of the present invention provides an application of the polymer provided by the present invention in improving the crude oil recovery rate of high-temperature and high-salinity oil reservoirs, wherein the temperature of the high-temperature and high-salinity oil reservoir is 80-90℃ and the salt content is 15g / L-25g / L.

[0015] The beneficial effects of the present invention through the above technical solution include at least the following:

[0016] This invention, from a molecular design perspective, introduces surface-active structural units B and C into the macromolecular structure of polyacrylamide. This provides surface activity to the polymer and improves the polymer's temperature and salt resistance. In a preferred embodiment, adding molecular weight regulators to the polymerization system not only adjusts the polymer's molecular weight but also increases the polymerization activity of the carbon-carbon double bonds in monomers E and F, allowing them to copolymerize with acrylamide (monomer D) and various other olefin monomers to form different functional polymers. In this invention, the surface-active polymer 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. It possesses the dual functions of viscoelastic oil displacement and active oil washing, and can replace currently used polymer / surfactant binary composite flooding in oilfields, solving problems such as chromatographic separation effects in formations associated with binary composite flooding.

[0017] The surface-active polymer of this invention effectively solves the problems of poor temperature resistance and resistance to inorganic high-valence cations in existing oil displacement systems. Furthermore, the aqueous solution of this polymer exhibits excellent surface activity. Therefore, this type of polymer-based oil displacement agent is suitable for high-temperature, high-salinity Class III oil reservoirs and can further improve crude oil recovery rates in tertiary oil recovery processes.

[0018] In a preferred embodiment of the present invention, the viscosity-average molecular weight of the polymer can reach over 12 million. It is prepared into a 1500 mg / L aqueous solution using a brine solution with a mineralization of 15 g / L, at a shear rate of 7.34 s⁻¹. -1 At a temperature of 90℃, its apparent viscosity is 13.5-24.2 mPa·s. When prepared into a 1500 mg / L aqueous solution using brine with a mineralization of 25 g / L, its viscosity is measured at a shear rate of 7.34 s⁻¹. -1 At a temperature of 90℃, its apparent viscosity ranges from 10.8 to 18.3 mPa·s. When the polymer concentration is 1500 mg / L, the surface tension of the polymer aqueous solution is between 31 and 36.6 mN / m, exhibiting good surface activity. Detailed Implementation

[0019] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0020] The first aspect of the present invention provides a polymer, wherein the polymer contains structural unit A, structural unit B, and structural unit C; structural unit A is... Structural unit B is selected from At least one of them, the structural unit C is selected from At least one of them;

[0021] Wherein, R1 and R2 are alkyl groups, and R3 is a C group. 10 -C 17 Alkyl groups, n is an integer from 7 to 20, p is an integer from 2 to 6, and M is an alkali metal element.

[0022] This invention, from a molecular design perspective, introduces surface-active structural units B and C into the macromolecular structure of polyacrylamide. This provides surface activity to the polymer and improves the temperature and salt resistance of the polymer product. In this invention, the surface-active polymer combines the thickening properties of a high molecular weight polymer with the surface activity of a low molecular weight surfactant, 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.

[0023] According to the present invention, preferably, R1 is C1-C 10 The alkyl group is preferably CH3; n is an integer from 7 to 10, preferably 9; R3 is C 12Alkyl groups, preferably C 12 Straight-chain alkyl groups.

[0024] According to the present invention, preferably, p = 3; R2 is C4-C 20 Alkyl groups.

[0025] In this invention, C4-C 20 The alkyl group can be a straight-chain alkyl group or a branched alkyl group. Preferably, R is n-butyl, sec-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl or n-eicosyl, more preferably n-dodecyl, n-tetradecyl or n-hexadecyl.

[0026] The inventors of this invention have discovered that polymers composed of specific structural units A, B, and C can further improve the oil displacement effect when used as oil displacement agents. For example,

[0027] In a preferred embodiment of the present invention, structural unit A is Structural unit B is Structural unit C is selected from When the polymer is used as an oil displacement agent, it can achieve a better oil displacement effect when it is selected from at least one of the following:

[0028] According to the present invention, preferably, based on the total weight of the polymer, the contents of structural unit A, structural unit B and structural unit C in the polymer are 60-89 wt%, 10-30 wt% and 1-30 wt%, respectively, and more preferably 70-85 wt%, 10-20 wt% and 1-10 wt%.

[0029] According to the present invention, preferably, the polymer has a viscosity-average molecular weight of 11 million to 16.1 million g / mol, more preferably 12 million to 16.1 million g / mol.

[0030] According to the present invention, preferably, the intrinsic viscosity of the polymer at 25°C is 2100-2790 mL / g, more preferably 2200-2790 mL / g.

[0031] According to the present invention, preferably, the surface tension of the aqueous solution of the polymer at a concentration of 1500 mg / L is 31-40 mN / m at 30°C, more preferably 31-35 mN / m.

[0032] A second aspect of the present invention provides a method for preparing a polymer, wherein the method comprises the following steps: polymerizing monomers in the presence of an initiator and a solvent, wherein the polymerizing monomers include monomer D, monomer E, and monomer F; monomer D is... Monomer E is selected from At least one of them, monomer F is selected from At least one of them;

[0033] Wherein, R1 and R2 are alkyl groups, and R3 is a C group. 10 -C 17 Alkyl groups, n is an integer from 7 to 20, p is an integer from 2 to 6, and M is an alkali metal element.

[0034] According to the present invention, R1 is C1-C 10 The alkyl group is preferably CH3; n is an integer from 7 to 10, preferably 9; R3 is C 12 Alkyl groups, preferably C 12 Straight-chain alkyl groups.

[0035] According to the present invention, preferably, p = 3; R2 is C4-C 20 The alkyl group is preferably n-butyl, sec-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl or n-eicosyl, more preferably n-dodecyl, n-tetradecyl or n-hexadecyl.

[0036] The inventors of this invention have discovered that polymers obtained by polymerization of specific monomers D, E, and F can further improve the oil displacement effect when used as oil displacement agents. For example,

[0037] In a preferred embodiment of the present invention, monomer D is... Monomer E is Monomer F is selected from When at least one of monomers D, E, and F is used, the polymer obtained by polymerization of monomers D, E, and F can achieve a better oil displacement effect when used as an oil displacement agent.

[0038] According to the present invention, preferably, the contents of monomer D, monomer E and monomer F in the polymeric monomer are 60-89 wt%, 10-30 wt% and 1-30 wt%, respectively, and more preferably 70-85 wt%, 10-20 wt% and 1-10 wt%.

[0039] The present invention does not impose particular restrictions on the relationship between the amount of solvent and monomer used in the polymerization reaction, and the amounts can vary within a wide range. Preferably, when carrying out the polymerization reaction, the amount of monomer used is 15-35 wt%, preferably 20-30 wt%, based on the total weight of the solvent and monomer.

[0040] The present invention does not impose any particular limitation on the amount of initiator used in the polymerization reaction, and it can vary within a wide range. Preferably, the amount of initiator is 0.01-0.1% by weight, based on the total weight of the polymerizable monomers.

[0041] The present invention does not have any particular restrictions on the type of solvent for the polymerization reaction, as long as it enables the monomers to undergo polymerization smoothly. Preferably, the solvent is water.

[0042] This invention does not impose any particular limitation on the type of initiator used in the polymerization reaction; the initiator can be any of the free radical polymerization initiators commonly used in the art. Preferably, the initiator is selected from at least one of azo initiators, peroxide initiators, and redox initiators, and is more preferably a redox initiator.

[0043] The azo initiator may be 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 may be selected from at least one of hydrogen peroxide, ammonium persulfate, sodium persulfate, potassium persulfate, benzoyl peroxide, and benzoyl tert-butyl peroxide; the redox initiator may be selected from at least one of sulfate-sulfite, persulfate-thiourea, persulfate-organic salt, and ammonium persulfate-aliphatic amine.

[0044] According to the present invention, in order to further prevent the influence of metal ions on the polymerization reaction, the polymerization reaction is preferably carried out in the presence of a chelating agent, wherein the chelating agent is selected from at least one of disodium ethylenediaminetetraacetate, aminotriacetic acid and ammonium citrate, preferably disodium ethylenediaminetetraacetate.

[0045] According to the present invention, preferably, the amount of the chelating agent is 0.08-0.3% by weight, based on the total weight of the polymerizable monomers.

[0046] According to the present invention, in order to improve the solubility of the copolymer in a solvent, the polymerization reaction is preferably carried out in the presence of an auxiliary agent selected from at least one of urea, thiourea and ammonia, preferably urea.

[0047] According to the present invention, preferably, the amount of the auxiliary agent is 0.01-0.1% by weight, based on the total weight of the polymerizable monomers.

[0048] According to the present invention, preferably, the polymerization reaction is carried out in the presence of a molecular weight regulator. The addition of a molecular weight regulator to the polymerization system can not only adjust the molecular weight of the polymer, but also increase the polymerization activity of the carbon-carbon double bonds in the molecular structures of monomers E and F, so that they can copolymerize with acrylamide (monomer D) to generate different functional polymers. In a preferred case, the molecular weight regulator is selected from at least one of isopropanol, ammonia, N,N'-methylenebisacrylamide and dimethylthiourea.

[0049] This invention does not impose any particular limitation on the amount of molecular weight regulator used during the polymerization reaction; the amount is adjusted according to the desired molecular weight of the synthesized polymer. Preferably, during the polymerization reaction, the amount of the molecular weight regulator is such that the viscosity-average molecular weight of the polymer obtained after the polymerization reaction is 11 million to 16.1 million g / mol, more preferably 12 million to 16.1 million g / mol.

[0050] According to the present invention, preferably, the temperature of the polymerization reaction is 0-25°C, more preferably 0-15°C; and the time is 2-15h, more preferably 10-15h.

[0051] According to the present invention, preferably, the polymerization reaction is carried out under conditions with a pH value of 7-10, and more preferably under conditions with a pH value of 7-9.

[0052] According to the present invention, the above-mentioned 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.

[0053] According to the present invention, preferably, the polymerization reaction is carried out in the presence of a protective gas, which is a gas that does not react with the raw materials and products. The protective gas is preferably nitrogen and / or a gas of a group 0 element in the periodic table, and more preferably nitrogen and / or argon.

[0054] In a preferred embodiment, the method of the present invention further includes purifying and drying the mixture obtained from the polymerization reaction to obtain a purified polymer. The purification is preferably performed using acetone for precipitation purification.

[0055] A third aspect of the present invention provides a polymer prepared by the preparation method provided by the present invention.

[0056] The fourth aspect of the present invention provides an application of the polymer provided by the present invention in improving the crude oil recovery rate of high-temperature and high-salinity oil reservoirs, wherein the temperature of the high-temperature and high-salinity oil reservoir is 80-90℃ and the salt content is 15g / L-25g / L.

[0057] 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.

[0058] The present invention will be described in detail below through examples and comparative examples. Unless otherwise specified, the methods used in the following examples are conventional; the reagents and materials used are commercially available unless otherwise specified.

[0059] The testing method involved in this invention is as follows:

[0060] The dissolution time and solid content of the polymer were determined according to the method specified in GB12005.8-89.

[0061] 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 in a 10wt% NaCl solution.

[0062] 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.

[0063] The apparent viscosity of the polymer solution was measured using a Brookfield DV-III viscometer at a constant shear rate of 7.34 s⁻¹. -1 .

[0064] Surface tension was measured using a Dataphysics DCAT21 surface tension meter.

[0065] Molecular structural formulas and the composition of structural units are quantitatively analyzed. 13 C-spectrum determination.

[0066] All reagents used in the examples were commercially available chemically pure reagents. The polymer sample KYP used in the comparative examples was an in-use sample provided by the oil field. 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 was 75 wt%, the content of 2-methyl-2-acrylamidopropanesulfonic acid structural units was 25 wt%, the viscosity-average molecular weight of KYP was 10.1 million, and the intrinsic viscosity was 1915 mL / g.

[0067] Example 1

[0068] The aqueous solution polymerization method was used, and 264.375g of acrylamide and 75g of n-dodecyl alcohol polyoxyethylene ether methacrylate were added to the polymerization reaction flask. 35.625g surfactant monomer M1 ( Where C 12 H 25 The monomer is n-dodecyl (prepared according to the method in Daily Chemical Industry, 2006, 36(6):345-347) and distilled water. Based on the total content of monomer and distilled water, the total content of monomer is 25% by weight. The mixture is stirred thoroughly until the solution in the polymerization flask becomes a transparent solution. Then, 200 mg of urea, 360 mg of disodium ethylenediaminetetraacetate, and 140 mg of isopropanol are added. At the same time, the pH of the system is adjusted to 7.5 with sodium hydroxide. The initial temperature of the system is controlled at 10°C. High-purity nitrogen gas with a volume concentration of 99.99% is introduced for 30 minutes to remove oxygen from the polymerization flask. Then, 100 mg of ammonium persulfate and 50 mg of sodium bisulfite are added in sequence. High-purity nitrogen gas is introduced for another 10 minutes. The reactor is sealed and the reaction is carried out for 10 hours to obtain a transparent polymer with viscosity. The gel-like product is taken out, granulated, dried, crushed, and sieved to obtain the high molecular weight surface-active functional polymer product P1.

[0069] Performance determination of polymer P1: Quantitative analysis 13 The C-ray diffraction (C-C) spectrum showed C=O and -CH2-SO3 at 175.10 ppm, 89.25 ppm, and 69.36 ppm, respectively. - The characteristic peaks of the COC bond, along with the superposition of the characteristic peaks of -CH-CH2- and C=O bonds on the main chain, confirm that the obtained copolymer molecule possesses... The structure shown can be calculated using the integrated area of ​​the characteristic peaks, yielding a x1:y1:z1 ratio of 1:0.031:0.022. The intrinsic viscosity of polymer P1 is 2210 mL / g, and the viscosity-average molecular weight is 12.15 million g / mol.

[0070] Example 2

[0071] An aqueous solution polymerization method was used, in which 292.5g of acrylamide and 45g of n-dodecyl alcohol polyoxyethylene ether methacrylate were added to a polymerization reaction flask. 37.5g surfactant monomer M1 ( Where C 12 H 25The monomer is n-dodecyl (obtained according to the method in Daily Chemical Industry, 2006, 36(6):345-347) and distilled water. Based on the total content of monomer and distilled water, the total content of monomer is 25% by weight. The mixture is stirred thoroughly until the solution in the polymerization flask becomes a transparent solution. Then, 120 mg of urea, 400 mg of disodium ethylenediaminetetraacetate, 5 mL of ammonia and 120 mg of isopropanol are added. At the same time, the pH of the system is adjusted to 8 with sodium hydroxide, and the initial temperature of the system is controlled at 10°C. High-purity nitrogen gas with a volume concentration of 99.99% is introduced for 30 minutes to remove oxygen from the polymerization flask. Then, 60 mg of ammonium persulfate and 30 mg of sodium bisulfite are added in sequence, and high-purity nitrogen gas is introduced for another 10 minutes. The reactor is sealed and the reaction is carried out for 12 hours to obtain a transparent polymer with viscosity. The gel-like product is taken out, granulated, dried, crushed and sieved to obtain the high molecular weight surface-active functional polymer product P2.

[0072] Performance determination of polymer P2: Quantitative analysis 13 The C-ray diffraction (C-C) spectrum showed C=O and -CH2-SO3 at 175.10 ppm, 89.25 ppm, and 69.36 ppm, respectively. - The characteristic peaks of the COC bond, along with the superposition of the characteristic peaks of -CH-CH2- and C=O bonds on the main chain, confirm that the obtained copolymer molecule possesses... The structure shown can be calculated using the integrated areas of the characteristic peaks, yielding a x1:y1:z1 ratio of 1:0.017:0.021. The intrinsic viscosity of polymer P2 is 2311 mL / g, and the viscosity-average molecular weight is 12.85 million g / mol.

[0073] Example 3

[0074] An aqueous solution polymerization method was used, and 301.875 g of acrylamide and 46.875 g of n-dodecyl alcohol polyoxyethylene ether methacrylate were added to the polymerization reaction flask. 26.25g surfactant monomer M2 ( Where C 14 H 29The monomer is tetradecyl (obtained according to the method described in Daily Chemical Industry, 2006, 36(6):345-347) and distilled water. Based on the total content of monomer and distilled water, the total content of monomer is 25% by weight. The mixture is stirred thoroughly until the solution in the polymerization flask becomes a transparent solution. Then, 100 mg of urea, 300 mg of disodium ethylenediaminetetraacetate, 10 mL of ammonia and 150 mg of isopropanol are added. At the same time, the pH of the system is adjusted to 7 with sodium hydroxide, and the initial temperature of the system is controlled at 7°C. High-purity nitrogen gas with a volume concentration of 99.99% is introduced for 30 minutes to remove oxygen from the polymerization flask. Then, 50 mg of ammonium persulfate and 25 mg of sodium bisulfite are added in sequence, and high-purity nitrogen gas is introduced for another 10 minutes. The reactor is sealed and the reaction is carried out for 12 hours to obtain a transparent polymer with viscosity. The gel-like product is taken out, granulated, dried, crushed and sieved to obtain the high molecular weight surface-active functional polymer product P3.

[0075] Performance determination of polymer P3: quantitative analysis 13 The C-ray diffraction (C-C) spectrum showed C=O and -CH2-SO3 at 175.10 ppm, 89.25 ppm, and 69.36 ppm, respectively. - The characteristic peaks of the COC bond, along with the superposition of the characteristic peaks of -CH-CH2- and C=O bonds on the main chain, confirm that the obtained copolymer molecule possesses... The structure shown can be calculated using the integral area of ​​the characteristic peaks, yielding a x1:y1:z1 ratio of 1:0.017:0.014. The intrinsic viscosity of polymer P3 is 2366 mL / g, and the viscosity-average molecular weight is 13.23 million g / mol.

[0076] Example 4

[0077] An aqueous solution polymerization method was used, and 305g of acrylamide and 53.25g of n-dodecyl alcohol polyoxyethylene ether methacrylate were added to the polymerization reaction flask. 16.75g surfactant monomer M2 ( Where C 14 H 29The monomer is tetradecyl (obtained according to the method described in Daily Chemical Industry, 2006, 36(6):345-347) and distilled water. Based on the total content of monomer and distilled water, the total content of monomer is 25% by weight. The mixture is stirred thoroughly until the solution in the polymerization flask becomes a transparent solution. Then, 150 mg of urea, 400 mg of disodium ethylenediaminetetraacetate, 5 mL of ammonia and 150 mg of isopropanol are added. At the same time, the pH of the system is adjusted to 8 with sodium hydroxide, and the initial temperature of the system is controlled at 5°C. High-purity nitrogen gas with a volume concentration of 99.99% is introduced for 30 minutes to remove oxygen from the polymerization flask. Then, 40 mg of ammonium persulfate and 20 mg of sodium bisulfite are added in sequence, and high-purity nitrogen gas is introduced for another 10 minutes. The reactor is sealed and the reaction is carried out for 12 hours to obtain a transparent polymer with viscosity. The gel-like product is taken out, granulated, dried, crushed and sieved to obtain the high molecular weight surface-active functional polymer product P4.

[0078] Performance determination of polymer P4: Quantitative analysis 13 The C-ray diffraction (C-C) spectrum showed C=O and -CH2-SO3 at 175.10 ppm, 89.25 ppm, and 69.36 ppm, respectively. - The characteristic peaks of the COC bond, along with the superposition of the characteristic peaks of -CH-CH2- and C=O bonds on the main chain, confirm that the obtained copolymer molecule possesses... The structure shown can be calculated using the integrated area of ​​the characteristic peaks, yielding a x1:y1:z1 ratio of 1:0.019:0.009. The intrinsic viscosity of polymer P4 is 2478 mL / g, and the viscosity-average molecular weight is 14.02 million g / mol.

[0079] Example 5

[0080] The aqueous solution polymerization method was used, and 300g of acrylamide and 63.75g of n-dodecyl alcohol polyoxyethylene ether methacrylate were added to the polymerization reaction flask. 11.25g surfactant monomer M3 ( Where C 16 H 33The monomer is a hexadecyl group (prepared according to the method described in Daily Chemical Industry, 2006, 36(6):345-347). Distilled water was added, with the total monomer content as the baseline (25% by weight). The mixture was stirred thoroughly until the solution in the polymerization flask became transparent. Then, 375 mg of urea, 760 mg of disodium ethylenediaminetetraacetate, 5 mL of ammonia, and 180 mg of isopropanol were added. Simultaneously, the pH of the system was adjusted to 7.0 with sodium hydroxide, and the initial temperature was controlled at 0°C. High-purity nitrogen (99.99% by volume) was introduced for 30 minutes to remove oxygen from the polymerization flask. Then, 100 mg of ammonium persulfate and 50 mg of sodium bisulfite were added sequentially, and high-purity nitrogen was introduced for another 10 minutes. The reactor was then sealed, and the reaction was allowed to proceed 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 P5.

[0081] Performance determination of polymer P5: Quantitative analysis 13 The C-ray diffraction (C-C) spectrum showed C=O and -CH2-SO3 at 175.10 ppm, 89.25 ppm, and 69.36 ppm, respectively. - The characteristic peaks of the COC bond, along with the superposition of the characteristic peaks of -CH-CH2- and C=O bonds on the main chain, confirm that the obtained copolymer molecule possesses... The structure shown can be calculated using the integrated area of ​​the characteristic peaks, yielding a x1:y1:z1 ratio of 1:0.023:0.006. The intrinsic viscosity of polymer P5 is 2610 mL / g, and the viscosity-average molecular weight is 14.96 million g / mol.

[0082] Example 6

[0083] An aqueous solution polymerization method was used, and 318.75 g of acrylamide and 37.5 g of n-dodecyl alcohol polyoxyethylene ether methacrylate were added to the polymerization reaction flask. 18.75g surfactant monomer M3 ( Where C 16 H 33The monomer is a hexadecyl group (prepared according to the method described in Daily Chemical Industry, 2006, 36(6):345-347). Distilled water was added, with the total monomer content as the basis. The total monomer content was 25% by weight. The mixture was stirred thoroughly until the solution in the polymerization flask became transparent. Then, 320 mg of urea, 480 mg of disodium ethylenediaminetetraacetate, 10 mL of ammonia, and 150 mg of isopropanol were added. Simultaneously, the pH of the system was adjusted to 8 with sodium hydroxide, and the initial temperature was controlled at 0°C. High-purity nitrogen gas with a volume concentration of 99.99% was introduced for 30 minutes to remove oxygen from the polymerization flask. Then, 30 mg of ammonium persulfate and 15 mg of sodium bisulfite were added sequentially, and high-purity nitrogen gas was introduced for another 10 minutes. The reactor was then sealed, and the reaction was allowed to proceed 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.

[0084] Performance determination of polymer P6: quantitative analysis 13 The C-ray diffraction (C-C) spectrum showed C=O and -CH2-SO3 at 175.10 ppm, 89.25 ppm, and 69.36 ppm, respectively. - The characteristic peaks of the COC bond, along with the superposition of the characteristic peaks of -CH-CH2- and C=O bonds on the main chain, confirm that the obtained copolymer molecule possesses... The structure shown can be calculated using the integral area of ​​the characteristic peaks, yielding a x1:y1:z1 ratio of 1:0.013:0.009. The intrinsic viscosity of polymer P6 is 2760 mL / g, and the viscosity-average molecular weight is 16.04 million g / mol.

[0085] Example 7

[0086] The polymer product was prepared according to the method of Example 6, except that the type of monomer E was different. Specifically, "n-dodecyl alcohol polyoxyethylene ether methacrylate" was used. n=15” replaces an equal weight of “n-dodecyl alcohol polyoxyethylene ether methacrylate” n=9”. This yields P7, a high molecular weight surface-active functional polymer product.

[0087] Performance determination of polymer P7: quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6. The x1:y1:z1 ratio can be calculated as 1:0.009:0.009 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer P7 is 2140 mL / g, and the viscosity-average molecular weight is 11.67 million g / mol.

[0088] Example 8

[0089] The polymer product was prepared according to the method of Example 6, except that the type of monomer F was different. Specifically, it was prepared using " R2 is n-butyl, replacing an equal weight of " R2 is a hexadecyl group. This yields a high molecular weight surface-active functional polymer product, P8.

[0090] Performance determination of polymer P8: quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6. The x1:y1:z1 ratio can be calculated as 1:0.013:0.013 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer P8 is 2489 mL / g, and the viscosity-average molecular weight is 14.1 million g / mol.

[0091] Example 9

[0092] The polymer product was prepared according to the method of Example 6, except that the type of monomer F was different. Specifically, monomer F was n-dodecyl. R2 is tetradecyl A mixture with a mass ratio of 1:1 was used to obtain a high molecular weight surface-active functional polymer product, P9.

[0093] Performance determination of polymer P9: Quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6. The x1:y1:z1 ratio can be calculated as 1:0.013:0.010 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer P9 is 2645 mL / g, and the viscosity-average molecular weight is 15.21 million g / mol.

[0094] Example 10

[0095] The polymer product was prepared according to the method of Example 6, except that the weight ratios of monomers D, E, and E were different. Specifically, the amount of monomer D (acrylamide) added was 225 g, and monomer E... The amount added was 112.5g, monomer F The amount added was 37.5g. A high molecular weight surface-active functional polymer product, P10, was obtained.

[0096] Performance determination of polymer P10: Quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6. The x1:y1:z1 ratio can be calculated to be 1:0.055:0.024 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer P10 is 2100 mL / g, and the viscosity-average molecular weight is 11.4 million g / mol.

[0097] Example 11

[0098] The polymer product was prepared according to the method of Example 6, except that the type of chelating agent was different. Specifically, ammonium citrate was used instead of an equal weight of disodium ethylenediaminetetraacetate. A high molecular weight surface-active functional polymer product, P11, was obtained.

[0099] Performance determination of polymer P11: Quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6, and the integrated area ratio of the characteristic peaks is also the same as in Example 6. The intrinsic viscosity of polymer P11 is 2149 mL / g, and the viscosity-average molecular weight is 11.73 million g / mol.

[0100] Example 12

[0101] The polymer product was prepared according to the method of Example 6, except that the type of auxiliary agent was different. Specifically, thiourea was used instead of an equal weight of urea. A high molecular weight surface-active functional polymer product, P12, was obtained.

[0102] Performance determination of polymer P12: Quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6, and the integrated area ratio of the characteristic peaks is also the same as in Example 6. The intrinsic viscosity of polymer P12 is 2116 mL / g, and the viscosity-average molecular weight is 11.51 million g / mol.

[0103] Example 13

[0104] The polymer product was prepared according to the method of Example 6, except that the pH value during the polymerization reaction was different. Specifically, "adjust the pH value of the system to 8" was replaced with "adjust the pH value of the system to 10". A high molecular weight surface-active functional polymer product P13 was obtained.

[0105] Performance determination of polymer P13: quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6, and the integrated area ratio of the characteristic peaks is also the same as in Example 6. The intrinsic viscosity of polymer P13 is 2105 mL / g, and the viscosity-average molecular weight is 11.43 million g / mol.

[0106] Comparative Example 1

[0107] The polymer product was prepared according to the method of Example 6, except that "n-dodecyl alcohol polyoxyethylene ether methacrylate" was used. "Replace with an equal weight" C 16 H 33 "It is n-hexadecyl." This yielded polymer product D1.

[0108] Performance determination of polymer D1: quantitative analysis 13The characteristic peaks of C=O and COC bonds appeared at 175.50 ppm and 69.66 ppm in the C-spectrum, respectively, confirming that the obtained copolymer molecules possess... The structure shown shows that the x1:y1 ratio can be calculated to be 1:0.019 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer D1 is 1507 mL / g, and the viscosity-average molecular weight is 7.53 million g / mol.

[0109] Comparative Example 2

[0110] The polymer product was prepared according to the method of Example 6, except that the n value in monomer E was different. Specifically, monomer E The value of n is 2. Polymer product D2 is obtained.

[0111] Performance determination of polymer D2: quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are approximately the same as in Example 6. The x1:y1:z1 ratio can be calculated as 1:0.024:0.009 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer D2 is 1340 mL / g, and the viscosity-average molecular weight is 6.5 million g / mol.

[0112] Comparative Example 3

[0113] The surface-active polymer was prepared according to the method of Example 6, except that octadecyl alcohol polyoxyethylene ether methacrylate was used. Replace with an equal weight of dodecyl alcohol polyoxyethylene ether methacrylate Obtain polymer product D3.

[0114] Performance determination of polymer D3: quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are similar to those in Example 6. The x1:y1:z1 ratio can be calculated as 1:0.011:0.009 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer D3 is 1253 mL / g, and the viscosity-average molecular weight is 5.98 million g / mol.

[0115] Comparative Example 4

[0116] The surface-active polymer was prepared according to the method of Example 6, except that... Replace with an equal weight Obtain polymer product D4.

[0117] Performance determination of polymer D4: quantitative analysis 13 The positions of the characteristic peaks in the C-NMR spectrum are similar to those in Example 6. The x1:y1:z1 ratio can be calculated as 1:0.013:0.008 based on the integrated area of ​​the characteristic peaks. The intrinsic viscosity of polymer D3 is 1563 mL / g, and the viscosity-average molecular weight is 7.88 million g / mol.

[0118] Test case

[0119] Polymer solutions were prepared using simulated formation water with oilfield salinity of 15 g / L and 25 g / L, respectively, for the polymers obtained in each example and comparative example. The polymer solution concentration was 1500 mg / L, and the shear rate was 7.34 s⁻¹. -1 Under the conditions specified, the apparent viscosity of solutions prepared from the polymers obtained in each embodiment and comparative example, as well as the KYP solution, at 90°C is shown in Table 1. The surface tension of aqueous solutions of the polymers obtained in each embodiment and comparative example, with a concentration of 1500 mg / L, and the KYP aqueous solutions prepared using simulated formation water with a mineralization of 10 g / L, at 30°C, is shown in Table 1. Here, mineralization refers to the Na+ content in the simulated formation water. + K + Ca 2+ Mg 2+ Cl - SO4 2- CO3 2- The sum of the contents of inorganic ions, etc.

[0120] Table 1

[0121]

[0122]

[0123] As shown in Table 1, the polymers obtained in Examples 1-13 exhibit high apparent viscosity at high temperatures (90°C) and high mineralization (15-25 g / L). At 90°C and a mineralization of 15 g / L, the apparent viscosity of the polymer aqueous solution reaches 13.5-24.2 mPa·s. Even at a mineralization of 25 g / L, the apparent viscosity remains high, reaching 10.8-18.3 mPa·s, indicating that the surface-active polymers according to the present invention possess good temperature and salt resistance. At a polymer concentration of 1500 mg / L, the surface tension of the polymer aqueous solution is between 31-36.6 mN / m, demonstrating good surface activity. The aqueous solution of the acrylamide polymer designated KYP exhibits low apparent viscosity and a surface tension of 64.1 mN / m at high temperatures and high mineralization, indicating virtually no surface activity. The polymer product of Comparative Example 1 was polymerized from two monomers. In Comparative Example 2, the n value of monomer E was 2. In Comparative Example 3, R3 in monomer E was n-octadecyl. In Comparative Example 4, the n value of monomer F was 7. Compared with Examples 1-13, the aqueous solutions of the polymer products prepared in Comparative Examples 1-4 had lower apparent viscosity and poorer surface activity at high temperature and high salinity.

[0124] Furthermore, Example 7 changed the n value in monomer E, Example 8 changed the type of R2 in monomer F, Example 10 changed the weight ratio of monomer D, monomer E, and monomer E, Example 11 changed the type of chelating agent, Example 12 changed the type of auxiliary agent, and Example 13 changed the pH value during the polymerization reaction. Compared with Example 6, the aqueous solutions of the polymer products obtained in Examples 7-8 and 10-13 showed reduced apparent viscosity and surface activity at high temperature and high salinity. This indicates that when the types and weight ratios of monomer D, monomer E, and monomer E, the types of chelating agent and auxiliary agent, and the polymerization reaction conditions meet the preferred conditions, the temperature and salt resistance of the polymer can be further improved.

[0126] This improves performance and further enhances the surface activity of the polymer.

[0127] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A polymer, characterized in that, The polymer contains structural unit A, structural unit B and structural unit C; Structural unit A is Structural unit B is selected from At least one of them, the structural unit C is selected from At least one of them; Wherein, R1 and R2 are alkyl groups, and R3 is a C group. 10 -C 17 Alkyl groups, n is an integer from 7 to 20, p is an integer from 2 to 6, and M is an alkali metal element.

2. The polymer according to claim 1, characterized in that, R1 is C1-C 10 The alkyl group is preferably CH3; n is an integer from 7 to 10, preferably 9; R3 is C 12 Alkyl groups, preferably C 12 Straight-chain alkyl groups; Preferably, p = 3; R2 is C4-C 20 The alkyl group is preferably n-butyl, sec-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl or n-eicosyl, more preferably n-dodecyl, n-tetradecyl or n-hexadecyl.

3. The polymer according to claim 1 or 2, characterized in that, Based on the total weight of the polymer, the contents of structural unit A, structural unit B and structural unit C in the polymer are 60-89 wt%, 10-30 wt% and 1-30 wt%, respectively, preferably 70-85 wt%, 10-20 wt% and 1-10 wt%. Preferably, the polymer has a viscosity-average molecular weight of 11 million to 16.1 million g / mol, more preferably 12 million to 16.1 million g / mol.

4. The polymer according to any one of claims 1-3, characterized in that, The polymer has an intrinsic viscosity of 2100-2790 mL / g at 25°C, preferably 2200-2790 mL / g; Preferably, the surface tension of the aqueous solution of the polymer at a concentration of 1500 mg / L is 31-40 mN / m at 30°C, more preferably 31-35 mN / m.

5. A method for preparing a polymer, characterized in that, The preparation method includes the following steps: polymerizing monomers in the presence of an initiator and a solvent, wherein the monomers include monomer D, monomer E, and monomer F; monomer D is... Monomer E is selected from At least one of them, monomer F is selected from At least one of them; Wherein, R1 and R2 are alkyl groups, and R3 is a C group. 10 -C 17 Alkyl groups, where n is an integer from 7 to 20, p is an integer from 2 to 6, and M is an alkali metal element; Preferably, R1 is C1-C 10 The alkyl group is preferably CH3; n is an integer from 7 to 10, preferably 9; R3 is C 12 Alkyl groups, preferably C 12 Straight-chain alkyl groups; Preferably, p = 3; R2 is C4-C 20 The alkyl group is preferably n-butyl, sec-butyl, isobutyl, tert-butyl, n-hexyl, n-octyl, n-decyl, n-undecyl, n-dodecyl, n-tridecyl, n-tetradecyl, n-pentadecanyl, n-hexadecyl, n-heptadecyl, n-octadecyl, n-nonadecanyl or n-eicosyl, more preferably n-dodecyl, n-tetradecyl or n-hexadecyl.

6. The preparation method according to claim 5, characterized in that, The contents of monomers D, E and F in the polymer monomers are 60-89 wt%, 10-30 wt% and 1-30 wt%, respectively, preferably 70-85 wt%, 10-20 wt% and 1-10 wt%.

7. The preparation method according to claim 5 or 6, characterized in that, When carrying out the polymerization reaction, the amount of the polymeric monomer is 15-35 wt%, preferably 20-30 wt%, based on the total weight of the solvent and the polymeric monomer; Preferably, the amount of initiator is 0.01-0.1% by weight, based on the total weight of the polymerizable monomers; Preferably, the solvent is water; Preferably, the initiator is selected from at least one of azo initiators, peroxide initiators, and redox initiators, and is preferably a redox initiator.

8. The preparation method according to any one of claims 5-7, characterized in that, The polymerization reaction is carried out in the presence of a chelating agent, which is selected from at least one of disodium ethylenediaminetetraacetate, aminotriacetic acid, and ammonium citrate, preferably disodium ethylenediaminetetraacetate; Preferably, the amount of the chelating agent is 0.08-0.3% by weight, based on the total weight of the polymerizable monomers; Preferably, the polymerization reaction is carried out in the presence of an auxiliary agent selected from at least one of urea, thiourea, and ammonia, with urea being the most preferred. Preferably, the amount of the auxiliary agent is 0.01-0.1% by weight, based on the total weight of the polymerizable monomers. Preferably, the polymerization reaction is carried out in the presence of a molecular weight regulator selected from at least one of isopropanol, ammonia, N,N'-methylenebisacrylamide, and dimethylthiourea.

9. The preparation method according to any one of claims 5-8, characterized in that, The polymerization reaction is carried out at a temperature of 0-25℃, preferably 0-15℃, for a time of 2-15h, preferably 10-15h. Preferably, the polymerization reaction is carried out at a pH of 7-10, and more preferably at a pH of 7-9; Preferably, the polymerization reaction is carried out in the presence of a protective gas, which is preferably nitrogen and / or a gas of a Group 0 element in the periodic table, more preferably nitrogen and / or argon.

10. A polymer prepared by the method according to any one of claims 5-9.

11. The application of the polymer according to any one of claims 1-4 and 10 in improving the oil recovery rate of high-temperature, high-salinity oil reservoirs, wherein, The temperature of high-temperature and high-salinity oil reservoirs is 80-90℃, and the salt content is 15g / L-25g / L.

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