A functional monomer for synthesizing a thermally tackified polymer oil displacement agent and a preparation method thereof

Abstract

The present invention relates to a functional monomer for synthesizing a thermally tackifying polymer oil-displacing agent and a preparation method thereof. The present invention solves the problem that functional monomers used to synthesize thermally tackifying polymer oil-displacing agents are not suitable for promotion and application in the Daqing Oilfield. The present invention uses methoxy polyethylene glycol acrylate (MPEG), 2-aminoethyl isothiourea hydrochloride (AET·HCl), isophorone diisocyanate (IPDI), polyethylene glycol (PEG), and acrylic acid as raw materials, and is prepared through a stepwise reaction. The present invention also discloses a preparation method for the functional monomer used to synthesize a thermally tackifying polymer oil-displacing agent. The functional monomer of the present invention can be copolymerized with acrylamide to improve the heat resistance and stability of the polymer oil-displacing agent, making it suitable for use as an oil-displacing agent. The raw materials are widely available industrially, the synthesis process is simple, and it is easy to industrialize and mass-produce.

Description

Technical Field

[0001] The present invention relates to the technical field of tertiary oil recovery in oil field development, and in particular to a functional monomer for synthesizing a thermally tackified polymer oil displacement agent and a preparation method thereof. Background Art

[0002] During the high-water-cut development phase of the Daqing Oilfield, polymer flooding technology has become a key technology for maintaining stable oil production. Currently, the primary polymer used for flooding in the Daqing Oilfield is partially hydrolyzed polyacrylamide. However, with the widespread application of polymer flooding technology in the oilfield, partially hydrolyzed polyacrylamide has struggled to meet the requirements for further quality and efficiency improvements. Under formation water conditions (i.e., a temperature of 45°C, a total salinity of 4000-7000 mg / L, and a pH of 7.5-8.0), the polymer exhibits poor thermal stability. During reservoir migration, the partially hydrolyzed polyacrylamide's molecular chains are susceptible to hydrolysis and breakage, resulting in a significant decrease in its working viscosity within the reservoir. This necessitates a significant increase in polymer dosage, reducing the technical and economic benefits of polymer flooding. To address this issue, further improving the efficiency of polymer flooding requires enhancing the thermal stability of polymer flooding agents in Daqing formation water conditions. Temperature-induced polymer viscosity enhancement has become a research area.

[0003] Temperature-induced viscosity increase in polymer solutions is the most advantageous characteristic of thermal-viscosifying polymers containing thermosensitive functional monomers. Thermal-viscosifying polymers, also known as TVPs, are responsive to thermal stimuli, exhibiting an increase in viscosity with increasing temperature. This is due to the presence of functional side groups with a lower critical solution temperature (LCST) attached to the polymer molecular chains. When the ambient temperature is below the LCST, strong hydrogen bonds form between the polymer side chains and water molecules, rendering the entire macromolecular chain water-soluble. However, when the temperature is above the LCST, the hydrogen bonds between the polymer side chains and water molecules are disrupted, resulting in hydrophobicity and amphiphilicity of the entire polymer molecular chain. This characteristic results in low viscosity at low temperatures, making injection into reservoirs easier; at high temperatures, the viscosity increases, facilitating deep reservoir displacement. Common LCST functional monomers include N-alkyl acrylamides, PEO-containing polyethylene oxide, PPO-containing polypropylene oxide, or macromonomers based on PEO-PPO-PEO or diacetone acrylamide. Some of these temperature-sensitive functional monomers have low synthesis purity and yield; some are expensive and limited to laboratory research; and some have LCSTs higher than the Daqing reservoir temperature, making it difficult to achieve a viscosifying effect. These monomers are therefore unsuitable for widespread application in the Daqing Oilfield. For these reasons, it is necessary to develop a temperature-sensitive functional monomer suitable for the Daqing reservoir to prepare a thermal viscosifying polymer, enhance the heat resistance and stability of polymer flooding agents, and ultimately achieve the goal of improving the quality and efficiency of polymer flooding. Summary of the Invention

[0004] The purpose of the present invention is to overcome the shortcomings of the background technology and provide a functional monomer for synthesizing a thermally thickening polymer oil-displacing agent and a preparation method thereof. The functional monomer can be used for the modified copolymerization of polyacrylamide to improve the heat resistance and stability of the polymer oil-displacing agent.

[0005] The present invention is achieved through the following technical solution: a functional monomer for synthesizing a thermally thickened polymer oil displacement agent is prepared by stepwise reaction using methoxy polyethylene glycol acrylate MPEG, 2-aminoethylisothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, polyethylene glycol PEG, and acrylic acid as raw materials, and has the following structural formula:

[0006]

[0007] Where n1, n2, and n3 are the corresponding numbers of structural units.

[0008] The methoxy polyethylene glycol acrylate MPEG is one of MPEG-200, MPEG-350, MPEG-400, MPEG-500, MPEG-550, MPEG-600, MPEG-750, MPEG-1000, MPEG-1500, and MPEG-2000.

[0009] The polyethylene glycol PEG is one of PEG-200, PEG-300, PEG-400, PEG-600, PEG-800, PEG-1000, PEG-1500, PEG-2000, and PEG-3000.

[0010] A method for preparing a functional monomer for synthesizing a thermally tackifying polymer oil-displacing agent comprises the following steps:

[0011] (1) Dissolve an appropriate amount of methoxy polyethylene glycol acrylate (MPEG) in deionized water, transfer the mixture into a three-necked flask equipped with an electric stirrer, stir, and pass nitrogen through the flask to remove oxygen. Then, add 2-aminoethylisothiourea hydrochloride (AET·HCl) and an initiator. After the reaction is complete, add the reactant dropwise into stirred acetone, filter the precipitate, wash it several times with ether, and then freeze-dry it at low temperature to obtain an MPEG oligomer intermediate M1 with an amino terminal group.

[0012] (2) Equimolar amounts of intermediate M1 and isophorone diisocyanate (IPDI) were dissolved in dimethylformamide (DMF). The DMF solution of intermediate M1 was transferred to a three-necked flask equipped with an electric stirrer, and the DMF solution of isophorone diisocyanate (IPDI) was transferred to a constant pressure dropping funnel. Under stirring, the DMF solution of isophorone diisocyanate (IPDI) was added dropwise to the three-necked flask. After the addition was complete, the temperature was maintained constant to obtain intermediate M2.

[0013] (3) dissolving polyethylene glycol (PEG) in an amount equimolar to the intermediate M2 in step (2) in dimethylformamide (DMF), then transferring the mixture to another constant pressure dropping funnel, and adding the polyethylene glycol (PEG) DMF solution dropwise to the three-necked flask in step (2); after the addition is complete, pouring the reactants into a large amount of acetone, filtering the precipitate, purifying it by soaking it in ether, and freeze-drying it at low temperature to obtain the intermediate M3;

[0014] (4) A suitable amount of the intermediate M3 is dissolved in dimethylformamide (DMF), and an excess amount of acrylic acid in DMF is added dropwise. After the addition is complete, the reactant is poured into a large amount of acetone, the precipitate is filtered, and the precipitate is purified by soaking in ether and freeze-dried at low temperature to obtain the functional monomer of the present invention.

[0015] In the step (1), the mixture was transferred into a three-necked flask equipped with an electric stirrer, and deoxygenated by passing N2 for 30 min at a constant temperature of 30°C and a stirring rate of 200 rpm.

[0016] In the step (2), the DMF solution of isophorone diisocyanate IPDI is transferred to a constant pressure dropping funnel; the DMF solution of isophorone diisocyanate IPDI is added dropwise to the three-necked flask at a rate of 10 drops / minute at a constant temperature of 0°C and a stirring rate of 200 rpm; after the dropwise addition is completed, the reaction is continued at a constant temperature of 0°C for 30 minutes to obtain the intermediate M2.

[0017] In the step (3), the mixture is transferred to another constant pressure dropping funnel; at a constant temperature of 0°C and a stirring rate of 200 rpm, the DMF solution of polyethylene glycol PEG is added dropwise to the three-necked flask in step (2) at a rate of 10 drops / minute; after the addition is completed, the mixture is reacted at a constant temperature of 0°C for 30 minutes, then the temperature is raised to 30°C and the reaction is continued for 1 hour, the reactant is poured into a large amount of acetone, and the precipitate is filtered.

[0018] In the step (4), an appropriate amount of the intermediate M3 is dissolved in dimethylformamide (DMF), and an excess amount of acrylic acid in DMF is added dropwise at 25° C. After the addition is complete, the reaction is continued at 25° C. for 12 hours, and then the reactant is poured into a large amount of acetone and the precipitate is filtered.

[0019] The initiator in step (1) is potassium persulfate K2S2O8, the amount used is 0.01% of the total mass of the reaction system, and the reaction time is 8 hours.

[0020] In the step (4), the molar ratio of acrylic acid to the intermediate M3 is greater than 1.

[0021] Compared with the prior art, the present invention has the following beneficial effects:

[0022] 1. This invention proposes a functional monomer for synthesizing a thermally thickened polymer oil-displacing agent, enhancing the heat stability of modified polyacrylamide oil-displacing agents under the conditions of the Daqing oil reservoir. This functional monomer exhibits temperature-sensitive properties. When incorporated into the polyacrylamide molecular chain, it achieves a low viscosity polymer solution at ambient surface temperatures, facilitating injection into oil reservoirs. At reservoir temperatures, the solution viscosity increases, achieving a profile adjustment and displacement effect deep within the reservoir.

[0023] 2. The preparation method of the functional monomer for synthesizing the thermal viscosity-increasing polymer oil-displacing agent provided by the present invention has a wide range of industrial raw material sources, a simple synthesis process, and is easy to industrialize and mass-produce.

[0024] Description of the drawings: Figure 1 Schematic diagram of the synthesis route of the functional monomer of the present invention;

[0025] Figure 2 The functional monomer prepared in Example 1 of the present invention 1 H NMR spectrum;

[0026] Figure 3is the curve of polymer solution viscosity changing with temperature;

[0027] Figure 4 This is the curve of polymer solution viscosity retention rate changing with aging time.

[0028] Specific implementation: The present invention is further described below with reference to the accompanying drawings and embodiments, but the content of the present invention is not limited to the following embodiments.

[0029] As a specific embodiment, the functional monomer for synthesizing the thermal viscosity-increasing polymer oil displacement agent of the present invention, its preparation line is as shown in the attached Figure 1 As shown, the specific preparation method is as follows:

[0030] (1) Dissolve an appropriate amount of methoxy polyethylene glycol acrylate (MPEG) in deionized water and transfer it to a three-necked flask equipped with an electric stirrer. Deoxygenate with nitrogen at a constant temperature of 30°C and a stirring rate of 200 rpm for 30 minutes. Then add 2-aminoethylisothiourea hydrochloride (AET·HCl) and initiator K2S2O8. After the reaction is complete, add the reactants dropwise to stirred acetone, filter the precipitate, wash it several times with ether, and then freeze-dry it to obtain the MPEG oligomer intermediate M1 with an amino terminal group.

[0031] (2) Equimolar amounts of intermediate M1 and isophorone diisocyanate IPDI were dissolved in dimethylformamide (DMF) respectively. The DMF solution of intermediate M1 was transferred to a three-necked flask equipped with an electric stirrer, and the DMF solution of isophorone diisocyanate IPDI was transferred to a constant pressure dropping funnel. At a constant temperature of 0°C and a stirring rate of 200 rpm, the DMF solution of isophorone diisocyanate IPDI was added dropwise to the three-necked flask at a rate of 10 drops / minute. After the addition was completed, the reaction was continued at a constant temperature of 0°C for 30 minutes to obtain intermediate M2;

[0032] (3) Dissolve the polyethylene glycol PEG in an amount equimolar to the intermediate M2 in step (2) in dimethylformamide (DMF), and then transfer it to another constant pressure dropping funnel. Add the polyethylene glycol PEG DMF solution to the three-necked flask in step (2) at a rate of 10 drops / minute at a constant temperature of 0°C and a stirring rate of 200 rpm. After the titration is completed, react at a constant temperature of 0°C for 30 minutes, then raise the temperature to 30°C and continue the reaction for 1 hour. Pour the reactant into a large amount of acetone, filter the precipitate, purify it by soaking it in ether, and freeze-dry it at low temperature to obtain the intermediate M3.

[0033] (4) A suitable amount of intermediate M3 was dissolved in dimethylformamide (DMF), and an excess amount of acrylic acid in DMF solution was added dropwise at 25°C. After the solution was added, the reaction was continued at 25°C for 12 hours. The reactant was then poured into a large amount of acetone, the precipitate was filtered, and the product was purified by soaking in ether and freeze-dried to obtain the functional monomer of the present invention.

[0034] Example 1

[0035] This embodiment provides a functional monomer for synthesizing a thermally tackifying polymer oil displacement agent and a preparation method thereof.

[0036] In this embodiment, the methoxy polyethylene glycol acrylate MPEG is MPEG-500, and the polyethylene glycol PEG is PEG-400.

[0037] In this embodiment, the main raw material formula of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil displacement agent is as follows:

[0038] Methoxy polyethylene glycol acrylate MPEG-500: 30.0g;

[0039] 2-Aminoethylisothiourea hydrogen hydrochloride AET·HCl: 28.4 g;

[0040] Isophorone diisocyanate IPDI: 12.0 g;

[0041] Polyethylene glycol PEG-400: 19.5g;

[0042] Acrylic acid: 4.8g.

[0043] In this embodiment, the functional monomer used to synthesize the thermal viscosity-increasing polymer oil displacement agent is prepared by the following method:

[0044] (1) According to the synthesis formula of the functional monomer in this embodiment, the monomers and auxiliary agents are weighed according to the proposed measurement to prepare an initiator solution of a specific concentration;

[0045] (2) Dissolve methoxy polyethylene glycol acrylate MPEG-500 in deionized water and transfer it to a three-necked flask equipped with an electric stirrer. Deoxygenate with nitrogen at a constant temperature of 30°C and a stirring rate of 200 rpm for 30 minutes. Then add 2-aminoethylisothiourea hydrochloride AET·HCl and initiator potassium persulfate K2S2O8 and react for 8 hours. After the reaction is complete, add the reactant dropwise to stirred acetone, filter the precipitate, wash it several times with ether, and then freeze-dry it to obtain the MPEG oligomer intermediate M1 with an amino terminal group.

[0046] (3) Equimolar amounts of intermediate M1 and isophorone diisocyanate (IPDI) were dissolved in dimethylformamide (DMF). The DMF solution of intermediate M1 was transferred to a three-necked flask equipped with an electric stirrer, and the DMF solution of isophorone diisocyanate (IPDI) was transferred to a constant pressure dropping funnel. At a constant temperature of 0°C and a stirring rate of 200 rpm, the DMF solution of isophorone diisocyanate (IPDI) was added dropwise to the three-necked flask at a rate of 10 drops / minute. After the addition was completed, the reaction was continued at a constant temperature of 0°C for 30 minutes to obtain intermediate M2.

[0047] (4) Dissolve polyethylene glycol PEG-400 in an amount equimolar to the intermediate M2 in step (3) in dimethylformamide (DMF) and transfer the mixture to another constant pressure dropping funnel. Add the polyethylene glycol PEG-400 DMF solution to the three-necked flask in step (3) at a rate of 10 drops / minute at a constant temperature of 0°C and a stirring rate of 200 rpm. After the titration is completed, react at a constant temperature of 0°C for 30 minutes, then raise the temperature to 30°C and continue the reaction for 1 hour. Pour the reactant into a large amount of acetone, filter the precipitate, purify it by soaking it in ether, and freeze-dry it at low temperature to obtain the intermediate M3.

[0048] (5) A certain amount of intermediate M3 was dissolved in dimethylformamide (DMF), and an excess amount of acrylic acid in DMF solution was added dropwise at 25°C. After the solution was added, the reaction was continued at 25°C for 12 hours. The reactant was then poured into a large amount of acetone, the precipitate was filtered, and the product was purified by soaking in ether and freeze-dried to obtain the functional monomer of the present invention.

[0049] According to the raw material ratio and the actual product mass, the yield of the functional monomer in this embodiment is calculated to be 65.6%.

[0050] Take an appropriate amount of functional monomer and dissolve it in D2O, then transfer it to a nuclear magnetic resonance tube. 1 H NMR.

[0051] As attached Figure 2 As shown, the functional monomer of this embodiment 1 The H NMR spectrum analysis is as follows:

[0052] (1) The spectrum is mainly concentrated between 1.0 and 4.0 ppm, and no absorption peak is found above 7.0 ppm, indicating that the polymer molecule does not contain a benzene ring structure;

[0053] (2) There are two obvious peaks at 5.7~6.3ppm. By comparison, it is found that the peaks originate from the double bond proton peaks of acrylate in the macromonomer.

[0054] (3) Among all chemical shifts, 1.3 ppm and 3.6 ppm have the largest integrated areas. The peak at 1.3 ppm is the proton peak of the main chain -CH2- of polyacrylate, and the peak at 3.6 ppm is the proton peak of polyoxyethylene ether in the monomer.

[0055] (4) At 6.2 ppm, there is a -NH- proton peak of the urea group formed by isophorone diisocyanate and 2-aminoethylisothiourea.

[0056] (5) 4.4 ppm, 3.7 ppm, and 3.6 ppm are the proton peaks of -CH2- formed by the hydrogen of 2-aminoethylisothiourea in the monomer.

[0057] 1 The results of H NMR spectrum analysis showed that the molecular structure of the functional monomer contained methoxy polyethylene glycol acrylate MPEG-500, 2-aminoethyl isothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, and polyethylene glycol PEG-400 structural units, indicating that the functional monomer was successfully prepared and confirming the authenticity of the step-by-step reaction.

[0058] Example 2

[0059] This embodiment aims to change the molecular weight and raw material ratio of the homologous series and provide a functional monomer for synthesizing a thermally thickened polymer oil displacement agent.

[0060] In this embodiment, the methoxy polyethylene glycol acrylate MPEG is MPEG-200, and the polyethylene glycol PEG is PEG-200.

[0061] In this embodiment, the main raw material formula of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil displacement agent is as follows:

[0062] Methoxy polyethylene glycol acrylate MPEG-200: 30.0g;

[0063] 2-Aminoethylisothiourea hydrogen hydrochloride AET·HCl: 35.5 g;

[0064] Isophorone diisocyanate IPDI: 30.0 g;

[0065] Polyethylene glycol PEG-200: 24.3g;

[0066] Acrylic acid: 11.8 g;

[0067] In this embodiment, the preparation method of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil-displacing agent is the same as that in Example 1.

[0068] According to the raw material ratio and the actual product mass, the yield of the functional monomer in this embodiment is calculated to be 62.5%.

[0069] Example 3

[0070] This embodiment aims to change the molecular weight and raw material ratio of the homologous series and provide a functional monomer for synthesizing a thermally thickened polymer oil displacement agent.

[0071] In this embodiment, the methoxy polyethylene glycol acrylate MPEG is MPEG-200, and the polyethylene glycol PEG is PEG-3000.

[0072] In this embodiment, the main raw material formula of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil displacement agent is as follows:

[0073] Methoxy polyethylene glycol acrylate MPEG-200: 10.0g;

[0074] 2-Aminoethylisothiourea hydrogen hydrochloride AET·HCl: 11.8 g;

[0075] Isophorone diisocyanate IPDI: 10.1 g;

[0076] Polyethylene glycol PEG-3000: 121.5g;

[0077] Acrylic acid: 4.0g;

[0078] In this embodiment, the preparation method of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil-displacing agent is the same as that in Example 1.

[0079] According to the raw material ratio and the actual product mass, the yield of the functional monomer in this embodiment is calculated to be 61.2%.

[0080] Example 4

[0081] This embodiment aims to change the molecular weight and raw material ratio of the homologous series and provide a functional monomer for synthesizing a thermally thickened polymer oil displacement agent.

[0082] In this embodiment, the methoxy polyethylene glycol acrylate MPEG is MPEG-2000, and the polyethylene glycol PEG is PEG-200.

[0083] In this embodiment, the main raw material formula of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil displacement agent is as follows:

[0084] Methoxy polyethylene glycol acrylate MPEG-2000: 30.0g;

[0085] 2-Aminoethylisothiourea hydrogen hydrochloride AET·HCl: 10.6 g;

[0086] Isophorone diisocyanate IPDI: 3.0 g;

[0087] Polyethylene glycol PEG-200: 2.5g;

[0088] Acrylic acid: 1.3g;

[0089] In this embodiment, the preparation method of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil-displacing agent is the same as that in Example 1.

[0090] According to the raw material ratio and the actual product mass, the yield of the functional monomer in this embodiment is calculated to be 61.3%.

[0091] Example 5

[0092] This embodiment aims to change the molecular weight and raw material ratio of the homologous series and provide a functional monomer for synthesizing a thermally thickened polymer oil displacement agent.

[0093] In this embodiment, the methoxy polyethylene glycol acrylate MPEG is MPEG-2000, and the polyethylene glycol PEG is PEG-3000.

[0094] In this embodiment, the main raw material formula of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil displacement agent is as follows:

[0095] Methoxy polyethylene glycol acrylate MPEG-2000: 30.0g;

[0096] 2-Aminoethylisothiourea hydrogen hydrochloride AET·HCl: 7.1 g;

[0097] Isophorone diisocyanate IPDI: 3.0 g;

[0098] Polyethylene glycol PEG-3000: 36.5g;

[0099] Acrylic acid: 1.3g;

[0100] In this embodiment, the preparation method of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil-displacing agent is the same as that in Example 1.

[0101] According to the raw material ratio and the actual product mass, the yield of the functional monomer in this embodiment is calculated to be 60.2%.

[0102] Example 6

[0103] This embodiment aims to change the molecular weight and raw material ratio of the homologous series and provide a functional monomer for synthesizing a thermally thickened polymer oil displacement agent.

[0104] In this embodiment, the methoxy polyethylene glycol acrylate MPEG is MPEG-1000, and the polyethylene glycol PEG is PEG-1000.

[0105] In this embodiment, the main raw material formula of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil displacement agent is as follows:

[0106] Methoxy polyethylene glycol acrylate MPEG-1000: 30.0g;

[0107] 2-Aminoethylisothiourea hydrogen hydrochloride AET·HCl: 21.3 g;

[0108] Isophorone diisocyanate IPDI: 6.0 g;

[0109] Polyethylene glycol PEG-1000: 24.3g;

[0110] Acrylic acid: 2.4g;

[0111] In this embodiment, the preparation method of the functional monomer used to synthesize the thermal viscosity-increasing polymer oil-displacing agent is the same as that in Example 1.

[0112] According to the raw material ratio and the actual product mass, the yield of the functional monomer in this embodiment is calculated to be 64.3%.

[0113] Example 7

[0114] This embodiment aims to investigate whether the polymer prepared by using the functional monomer of the present invention has thermal viscosity increasing properties.

[0115] In this example, the functional monomers of Examples 1-6 were copolymerized with acrylamide AM monomers through free radical aqueous solution to prepare polymers, and parallel experiments were conducted with partially hydrolyzed polyacrylamide HPAM of the same molecular weight to compare the thermal viscosity-increasing properties of the polymers.

[0116] In this embodiment, the partially hydrolyzed polyacrylamide was produced by Daqing Refining and Chemical Company, with a solid content of about 90%, a hydrolysis degree of 20% to 25%, and a molecular weight of 700 to 950×10 4 g / mol. Partially hydrolyzed polyacrylamide is produced by free radical aqueous polymerization of acrylamide (AM) monomers. Sodium hydroxide is added during the granulation process for hydrolysis, converting some of the amide groups into sodium carboxylates, improving solubility.

[0117] In this example, the thermal tackifying polymer TVP is prepared as follows: acrylamide and a thermal tackifying monomer are added to deionized water under stirring, with the weight ratios of the two monomers being 23% and 0.5%, respectively. Urea and EDTA-2Na are then added, each at a weight ratio of 0.25%, and fully dissolved. 0.02% by weight of isopropyl alcohol is added, and the pH of the solution is adjusted to 7.0-8.0 with a 50% by weight NaOH solution to obtain a reaction solution. Under a low temperature and nitrogen atmosphere, 0.01% K₂S₂O₃ and 0.02% NaHSO₃ are added to initiate polymerization. The reaction is then incubated for 12 hours. The resulting polymer colloid is granulated, and NaOH and a dispersant are added. The granulate is sealed and hydrolyzed at 80-90°C for 2-3 hours. The granulate is then dried, crushed, and sieved to obtain the thermal tackifying polymer. The basic properties of the thermal tackifying polymer TVP and partially hydrolyzed polyacrylamide (HPAM) are shown in Table 1.

[0118] In this embodiment, the viscosity of the polymer solution was measured using an Ametek Brookfield DV2T viscometer. # Rotor, speed 6 rpm, shear rate 7.338 s -1 , the measurement temperature range is 20~60℃.

[0119] In this embodiment, the polymer solution was prepared by using simulated Daqing sewage. The concentration of the polymer solution was 1000 mg / L. The total mineralization of the simulated Daqing sewage was 4500 mg / L. 2+ Mg 2+ The total concentration is 65 mg / L.

[0120] Table 1

[0121] polymer Main monomer Functional monomer Degree of hydrolysis / % Solid content / % <![CDATA[Molecular weight / (×10 4 g / mol)]]> TVP-1 Acrylamide Example 1 23.1 90.8 850 TVP-2 Acrylamide Example 2 23.2 90.7 862 TVP-3 Acrylamide Example 3 24.2 91.3 842 TVP-4 Acrylamide Example 4 23.5 91.2 871 TVP-5 Acrylamide Example 5 24.1 90.1 842 TVP-6 Acrylamide Example 6 23.8 90.3 833 HPAM Acrylamide none 23.0 91.1 852

[0122] Under the same concentration conditions, the viscosity of different polymer solutions changes with temperature as shown in the attached figure. Figure 3 The curve shows that the viscosity of the HPAM solution gradually decreases with increasing temperature. Below the critical temperature of 40°C, the viscosity of the thermally thickening polymer solution decreases slightly with increasing temperature. Above the critical temperature of 40°C, the viscosity increases significantly with increasing temperature, exhibiting low viscosity at low temperatures and high viscosity at high temperatures. This demonstrates that the polymer prepared using the functional monomer of this invention exhibits thermally thickening properties.

[0123] Example 8

[0124] This embodiment aims to investigate the heat-resistant stability of polymers prepared using the functional monomers of the present invention.

[0125] In this example, the functional monomers of Examples 1-6 were used to copolymerize with acrylamide AM monomers through free radical aqueous solution to prepare polymers, and parallel experiments were conducted with partially hydrolyzed polyacrylamide HPAM of the same molecular weight to compare the heat stability of the polymers.

[0126] In this embodiment, the partially hydrolyzed polyacrylamide HPAM and the thermal viscosity-increasing polymer TVP are the same as those in Example 7.

[0127] In this embodiment, the viscosity retention rate is used to quantitatively characterize the heat stability of the polymer solution. The specific method is as follows: a polymer solution with a concentration of 1000 mg / L is prepared using simulated Daqing sewage, the polymer solution is placed in an ampoule, connected to the iHDAS-Ⅱ intelligent and efficient deoxygenation system, and the seal is melted after deoxygenation. The instrument is manufactured by Beijing Donghang Science and Technology Instrument Co., Ltd. The ampoule is placed in a 45°C constant temperature anaerobic glove box for constant temperature aging. The instrument is manufactured by Coy Laboratory Products Inc. in the United States. The viscosity of the polymer solution at different aging times is measured using a viscometer built into the glove box, and compared with the initial viscosity to calculate the viscosity retention rate. The viscosity retention rate and aging time curves of different polymer solutions are shown in Figure 4 .

[0128] In this embodiment, the viscosity of the polymer solution was measured using an Ametek Brookfield DV2T viscometer. #Rotor, speed 6 rpm, shear rate 7.338 s -1 , measured temperature 45℃.

[0129] In this embodiment, the components of the simulated Daqing sewage are the same as those in Example 7.

[0130] Attachment Figure 4 The results show that, under the same concentration conditions, the viscosity retention of polymer solutions decreases with aging time. At the same aging time, the viscosity retention of TVP polymer is significantly higher than that of HPAM. After 90 days of aging, the viscosity retention of HPAM is only 31.8%, while that of TVP polymer exceeds 60%. This shows that polymers prepared using the functional monomers of this invention possess excellent heat stability.

Claims

1. A functional monomer for synthesizing a thermally tackified polymer oil-displacing agent, characterized in that: The product is prepared by stepwise reaction of methoxy polyethylene glycol acrylate MPEG, 2-aminoethyl isothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, polyethylene glycol PEG and acrylic acid. A functional monomer for synthesizing a thermally tackified polymer oil displacement agent; its structural formula is as follows: Where n1, n2, and n3 are the corresponding numbers of structural units; The methoxy polyethylene glycol acrylate MPEG is MPEG-500; The polyethylene glycol PEG is PEG-400; The raw materials for synthesizing the functional monomers of the thermal viscosity-increasing polymer oil-displacing agent include 30.0 g of methoxy polyethylene glycol acrylate MPEG-500, 28.4 g of 2-aminoethylisothiourea hydrogen hydrochloride AET·HCl, 12.0 g of isophorone diisocyanate IPDI, 19.5 g of polyethylene glycol PEG-400, and 4.8 g of acrylic acid.

2. A functional monomer for synthesizing a thermally tackified polymer oil-displacing agent, characterized in that: The product is prepared by stepwise reaction of methoxy polyethylene glycol acrylate MPEG, 2-aminoethyl isothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, polyethylene glycol PEG and acrylic acid. A functional monomer for synthesizing a thermally tackified polymer oil displacement agent; its structural formula is as follows: Where n1, n2, and n3 are the corresponding numbers of structural units; The methoxy polyethylene glycol acrylate MPEG is MPEG-200; The polyethylene glycol PEG is PEG-200; The raw materials for synthesizing the functional monomers of the thermally tackifying polymer oil-displacing agent include 30.0 g of methoxy polyethylene glycol acrylate MPEG-200, 35.5 g of 2-aminoethylisothiourea hydrogen hydrochloride AET·HCl, 30.0 g of isophorone diisocyanate IPDI, 24.3 g of polyethylene glycol PEG-200, and 11.8 g of acrylic acid.

3. A functional monomer for synthesizing a thermally tackified polymer oil-displacing agent, characterized in that: The product is prepared by stepwise reaction of methoxy polyethylene glycol acrylate MPEG, 2-aminoethyl isothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, polyethylene glycol PEG and acrylic acid. A functional monomer for synthesizing a thermally tackified polymer oil displacement agent; its structural formula is as follows: Where n1, n2, and n3 are the corresponding numbers of structural units; The methoxy polyethylene glycol acrylate MPEG is MPEG-200; The polyethylene glycol PEG is PEG-3000; The raw materials for synthesizing the functional monomers of the thermally tackifying polymer oil-displacing agent include 10.0 g of methoxy polyethylene glycol acrylate MPEG-200, 11.8 g of 2-aminoethylisothiourea hydrogen hydrochloride AET·HCl, 10.1 g of isophorone diisocyanate IPDI, 121.5 g of polyethylene glycol PEG-3000, and 4.0 g of acrylic acid.

4. A functional monomer for synthesizing a thermally tackified polymer oil-displacing agent, characterized in that: The product is prepared by stepwise reaction of methoxy polyethylene glycol acrylate MPEG, 2-aminoethyl isothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, polyethylene glycol PEG and acrylic acid. A functional monomer for synthesizing a thermally tackified polymer oil displacement agent; its structural formula is as follows: Where n1, n2, and n3 are the corresponding numbers of structural units; The methoxy polyethylene glycol acrylate MPEG is MPEG-2000; The polyethylene glycol PEG is PEG-200; The raw materials for synthesizing the functional monomers of the thermal viscosity-increasing polymer oil-displacing agent include 30.0 g of methoxy polyethylene glycol acrylate MPEG-2000, 10.6 g of 2-aminoethylisothiourea hydrogen hydrochloride AET·HCl, 3.0 g of isophorone diisocyanate IPDI, 2.5 g of polyethylene glycol PEG-200, and 1.3 g of acrylic acid.

5. A functional monomer for synthesizing a thermally tackified polymer oil-displacing agent, characterized in that: The product is prepared by stepwise reaction of methoxy polyethylene glycol acrylate MPEG, 2-aminoethyl isothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, polyethylene glycol PEG and acrylic acid. A functional monomer for synthesizing a thermally tackified polymer oil displacement agent; its structural formula is as follows: Where n1, n2, and n3 are the corresponding numbers of structural units; The methoxy polyethylene glycol acrylate MPEG is MPEG-2000; The polyethylene glycol PEG is PEG-3000; The raw materials for synthesizing the functional monomers of the thermally tackifying polymer oil-displacing agent include 30.0 g of methoxy polyethylene glycol acrylate MPEG-2000, 7.1 g of 2-aminoethylisothiourea hydrogen hydrochloride AET·HCl, 3.0 g of isophorone diisocyanate IPDI, 36.5 g of polyethylene glycol PEG-3000, and 1.3 g of acrylic acid.

6. A functional monomer for synthesizing a thermally tackified polymer oil displacement agent, characterized in that: The product is prepared by stepwise reaction of methoxy polyethylene glycol acrylate MPEG, 2-aminoethyl isothiourea hydrochloride AET·HCl, isophorone diisocyanate IPDI, polyethylene glycol PEG and acrylic acid. A functional monomer for synthesizing a thermally tackified polymer oil displacement agent; its structural formula is as follows: Where n1, n2, and n3 are the corresponding numbers of structural units; The methoxy polyethylene glycol acrylate MPEG is MPEG-1000; The polyethylene glycol PEG is PEG-1000; The raw materials for synthesizing the functional monomers of the thermally tackifying polymer oil-displacing agent include 30.0 g of methoxy polyethylene glycol acrylate MPEG-1000, 21.3 g of 2-aminoethylisothiourea hydrogen hydrochloride AET·HCl, 6.0 g of isophorone diisocyanate IPDI, 24.3 g of polyethylene glycol PEG-1000, and 2.4 g of acrylic acid.

7. A method for preparing a functional monomer for synthesizing a thermally tackifying polymer oil-displacing agent using any one of claims 1 to 6, characterized in that: The following steps are involved: (1) Dissolve an appropriate amount of methoxy polyethylene glycol acrylate (MPEG) in deionized water, transfer the mixture into a three-necked flask equipped with an electric stirrer, stir, and pass nitrogen through the flask to remove oxygen. Then, add 2-aminoethylisothiourea hydrochloride (AET·HCl) and an initiator. After the reaction is complete, add the reactant dropwise into stirred acetone, filter the precipitate, wash it several times with ether, and then freeze-dry it to obtain an MPEG oligomer intermediate M1 with an amino terminal group. (2) Equimolar amounts of intermediate M1 and isophorone diisocyanate IPDI were dissolved in dimethylformamide (DMF) respectively; the DMF solution of intermediate M1 was transferred to a three-necked flask equipped with an electric stirrer, and the DMF solution of isophorone diisocyanate IPDI was transferred to a constant pressure dropping funnel; under stirring, the DMF solution of isophorone diisocyanate IPDI was added dropwise to the three-necked flask; after the addition was completed, the temperature was maintained constant to obtain intermediate M2; (3) The intermediate M2 in step (2) is equimolar to polyethylene glycol PEG and dissolved in dimethylformamide DMF, and then transferred to another constant pressure dropping funnel with stirring, and the DMF solution of polyethylene glycol PEG is added dropwise to the three-necked flask in step (2); After the titration is completed, the reactant is poured into a large amount of acetone, the precipitate is filtered, purified by soaking in ether, and freeze-dried at low temperature to obtain intermediate M3; (4) Dissolve an appropriate amount of intermediate M3 in dimethylformamide (DMF), add an excess of acrylic acid in DMF dropwise, and after the addition is complete, pour the reactants into a large amount of acetone, filter the precipitate, purify it by soaking it in ether, and freeze-dry it at low temperature to obtain the functional monomer of the present invention.

8. The method for preparing a functional monomer for synthesizing a thermally tackifying polymer oil-displacing agent according to claim 7, wherein: In the step (1), the mixture was transferred into a three-necked flask equipped with an electric stirrer, and deoxygenated by passing N2 for 30 min at a constant temperature of 30°C and a stirring rate of 200 rpm.

9. The method for preparing a functional monomer for synthesizing a thermally tackified polymer oil-displacing agent according to claim 7, characterized in that: In the step (2), the DMF solution of isophorone diisocyanate IPDI is transferred to a constant pressure dropping funnel; the DMF solution of isophorone diisocyanate IPDI is added dropwise to the three-necked flask at a rate of 10 drops / minute at a constant temperature of 0°C and a stirring rate of 200 rpm; after the dropwise addition is completed, the reaction is continued at a constant temperature of 0°C for 30 minutes to obtain the intermediate M2.

10. The method for preparing a functional monomer for synthesizing a thermally tackified polymer oil-displacing agent according to claim 7, characterized in that: In the step (3), the mixture is transferred to another constant pressure dropping funnel; at a constant temperature of 0°C and a stirring rate of 200 rpm, a DMF solution of polyethylene glycol PEG is added dropwise to the three-necked flask in step (2) at a rate of 10 drops / minute; After the titration is completed, the reaction is carried out at a constant temperature of 0°C for 30 minutes, then the temperature is raised to 30°C and the reaction is continued for 1 hour. The reactant is poured into a large amount of acetone and the precipitate is filtered.

11. The method for preparing a functional monomer for synthesizing a thermally tackifying polymer oil-displacing agent according to claim 7, characterized in that: In the step (4), an appropriate amount of the intermediate M3 is dissolved in dimethylformamide (DMF), and an excess amount of acrylic acid in DMF solution is added dropwise at 25° C. After the solution is added, the reaction is continued at 25° C. for 12 hours, and then the reactant is poured into a large amount of acetone and the precipitate is filtered.

12. The method for preparing a functional monomer for synthesizing a thermally tackifying polymer oil-displacing agent according to claim 7, characterized in that: The initiator in step (1) is potassium persulfate K2S2O8, the amount used is 0.01% of the total mass of the reaction system, and the reaction time is 8 hours.

13. The method for preparing a functional monomer for synthesizing a thermally tackifying polymer oil-displacing agent according to claim 7, characterized in that: In the step (4), the molar ratio of acrylic acid to the intermediate M3 is greater than 1.

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