A titanium-based quantum dot nanocomposite high-performance water-locking agent and its preparation method
The modified titanium quantum dot nanocomposite water-locking agent was prepared by hydrothermal method and combined with surfactant to solve the water lock blockage problem in low permeability reservoirs, achieving deep migration and water-locking effect without reservoir damage.
Patent Information
- Application Number
- CN202510629029.4
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- Filing Date
- 2025-05-16
- Publication Date
- 2025-09-30
- Estimated Expiration
- 2045-05-16
AI Technical Summary
Existing water-locking agents are difficult to effectively reduce the gas-water surface tension and interfacial tension in low permeability reservoirs, resulting in blockage of reservoir seepage channels and affecting gas well productivity.
Titanium quantum dots are prepared by a hydrothermal method and modified to form titanium-based quantum dot nanocomposite water-locking agents, which are combined with amphoteric, anionic-nonionic surfactants and antifoaming agents to synergistically reduce surface tension.
It achieves deep migration in low-permeability reservoirs, reduces the surface tension of deionized water to 19.3mN/m, avoids reservoir damage, and improves water-locking performance.
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Figure CN120137633B_ABST
Abstract
Description
Technical Field
[0001] The present invention belongs to the technical field of oil and gas field development, and in particular relates to a titanium-based quantum dot nanocomposite high-performance water-desorption and locking agent and a preparation method thereof. Background Art
[0002] Water breakthrough during or in the later stages of gas well production can cause some seepage channels to become blocked due to water lock, leading to a gradual decrease in gas production. For low-permeability gas reservoirs like those in the Ordos Basin, hydraulic fracturing is a key measure to improve reservoir conditions and increase production and efficiency. However, during post-fracturing flowback, water lock is a key factor affecting the efficiency of fracturing fluid flowback and a major cause of reservoir damage near the wellbore. Therefore, removing water lock is an effective method to restore reservoir seepage conditions, minimize damage, and maintain gas well productivity. The primary cause of water lock is excessively high gas-water surface tension and some condensate-water interfacial tension, resulting in capillary resistance and blocking gas flow channels. Therefore, removing water lock can only be achieved by reducing the surface and interfacial tension of the water phase.
[0003] Therefore, most common water-locking agents are based on surfactants, including anionic, nonionic, amphoteric, gemini, and pseudo-quadrant surfactants. However, in order to further enhance the surface activity of water-locking agents, the surface tension reduction performance of water-locking agents is enhanced by compounding different types of surfactants. Among them, functional nanomaterials and surfactants have significant synergistic effects and have been widely studied as efficient water-locking agents. However, conventional nanomaterials are limited by particle size and native dispersibility, making it difficult to exert their due performance in low permeability reservoirs. Summary of the Invention
[0004] In response to the defects of the existing technology, the present invention prepares and modifies titanium quantum dots by a hydrothermal method, and synergistically enhances the surfactant fluid to form a titanium-based quantum dot nanocomposite high-performance water-locking agent, and also provides a preparation method thereof.
[0005] A titanium-based quantum dot nanocomposite high-performance water-locking agent, which is composed of the following raw materials by weight, calculated as 100%: 0.03-0.1% amphiphilic titanium quantum dots, 0.2-0.4% amphoteric surfactant, 0.05-0.2% anionic-nonionic surfactant, 0.1-0.2% cosolvent, 0.1-0.3% antifoaming agent, and the balance water;
[0006] Among them, the amphiphilic titanium quantum dots are prepared by the following method: first, a titanate coupling agent is hydrolyzed and condensed by a hydrothermal method to form titanium-based quantum dots, then modified once by a silane coupling agent, and then a secondary surface in-situ polymerization modification is performed using functional monomers, wherein the functional monomers are hydrophobic monomers, acrylic acid and temperature-resistant and salt-resistant monomers.
[0007] Preferably, the amphiphilic titanium quantum dots are prepared by the following method:
[0008] (1) Under stirring, a titanate coupling agent is added dropwise to an activator and stirred to obtain solution A. Solution A and polyethylene glycol 2000 are dissolved in ethanol, stirred evenly, reacted at 130-180°C for 2-4 hours, washed with anhydrous ethanol, filtered, and dried to obtain titanium-based quantum dot nanopowders;
[0009] (2) Under ultrasonic and stirring conditions, the titanium-based quantum dot nanopowder is added to an ethanol aqueous solution, the pH is adjusted to 10, an ethanol solution of a silane coupling agent is added dropwise thereto, and the mixture is refluxed at 50-60° C. for 12-18 hours. After the reaction is completed, the mixture is extracted with petroleum ether and dried to obtain a silane coupling agent-modified titanium-based quantum dot nanopowder;
[0010] (3) Under ultrasonic and stirring conditions, the silane coupling agent-modified titanium-based quantum dot nanopowder and dispersant are added to deionized water, the functional monomer is added thereto, the pH is adjusted to 7-8, and then an aqueous solution of the initiator is added thereto, the mixture is stirred evenly, and the mixture is refluxed at 50-60° C. for 3-5 hours, extracted with ethyl acetate, and dried to obtain amphiphilic titanium quantum dots.
[0011] Preferably, in step (1), the ratio of titanate coupling agent, activator, polyethylene glycol 2000, and ethanol is (5-8) mL: 4 mL: (0.8-1.2) g: 100 mL;
[0012] The titanate coupling agent is one of tetraisopropyl titanate or n-butyl titanate;
[0013] The activator is a 1-5 wt % hydrochloric acid aqueous solution, a 20-25 wt % glacial acetic acid aqueous solution, or a 20-25 wt % lactic acid aqueous solution.
[0014] Preferably, in step (2), the mass of the silane coupling agent is 10-15% of the mass of the titanium-based quantum dot nanopowder;
[0015] The silane coupling agent is any one of vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyltriethoxysilane, and N-aminoethyl-3-aminopropyltrimethoxysilane;
[0016] The ethanol content in the ethanol aqueous solution is 80-85wt%.
[0017] Preferably, in step (3), the mass of the functional monomer accounts for 15-20% of the mass of the silane coupling agent modified titanium-based quantum dot nanopowder, the mass of the initiator accounts for 15-20% of the mass of the functional monomer, and the mass of the dispersant accounts for 0.8-1.5% of the total mass of the silane coupling agent modified titanium-based quantum dot nanopowder, deionized water, and the functional monomer;
[0018] The dispersant is any one of Tween 20, Tween 60, Tween 80, and dodecyl polyoxyethylene ether;
[0019] The initiator is any one or two of ammonium persulfate, ammonium sulfite, potassium persulfate, potassium sulfite, sodium persulfate, sodium sulfite, and hydrogen peroxide.
[0020] Preferably, based on the total mass of the functional monomers being 100%, the addition ratios of the hydrophobic monomer, acrylic acid, and the temperature- and salt-resistant monomer are 20-25%: 50-60%: 20-25%;
[0021] The hydrophobic monomer is any one of dodecyldimethylallyl ammonium chloride, tetradecyldimethylallyl ammonium chloride, hexadecyldimethylallyl ammonium chloride, octadecyldimethylallyl ammonium chloride, and octadecyl methacrylate;
[0022] The temperature-resistant and salt-resistant monomer is at least one of 2-acrylamide-2-methylpropanesulfonic acid, vinylbenzenesulfonic acid, vinylsulfonic acid, N-vinylpyrrolidone, and acryloylmorpholine;
[0023] Preferably, the drying is performed at 48-60° C. for 12-18 h; the ultrasonic power is 300 W; in step (2), 20-25 wt % ammonia solution is added dropwise to adjust the pH to 10; in step (3), 2-5 wt % sodium hydroxide solution is added dropwise to adjust the pH to 7-8; and in step (1), the filtration is performed by dialysis or centrifugation.
[0024] More preferably, the dialysis uses a dialysis bag with a molecular weight of 3 kDa, each dialysis lasts 4-6 hours, and the dialysis is performed 4-6 times.
[0025] More preferably, the centrifugal rotation speed is 6000-8000 rpm.
[0026] Preferably, the amphoteric surfactant is any one of oleamidopropyl betaine, oleamidopropyl hydroxysulfobetaine, hexadecyl hydroxysulfobetaine, hexadecyl propyl betaine, erucamidopropyl betaine, and erucamidopropyl hydroxysulfobetaine.
[0027] The anionic-nonionic surfactant is any one of sodium lauryl polyoxyethylene ether sulfate, fatty alcohol polyoxyethylene ether sulfonate, and sodium lauryl polyoxyethylene ether carboxylate.
[0028] Preferably, the foam suppressant is any one of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, and polyoxypropylene glycerol ether.
[0029] The co-solvent is at least one of isopropyl alcohol, methanol, propylene glycol and glycerol.
[0030] The preparation method of the titanium-based quantum dot nanocomposite high-performance water-locking agent comprises the following steps: uniformly dispersing amphiphilic titanium quantum dots in water under ultrasonic and stirring conditions at room temperature; then adding a cosolvent thereto under stirring conditions; stirring evenly; and then sequentially adding an amphoteric surfactant, an anionic-nonionic surfactant, and a foam suppressant thereto, and stirring until dissolved.
[0031] Advantages of the present invention:
[0032] The present invention adopts a hydrothermal method to hydrolyze a titanate coupling agent into titanium-based quantum dot nanoparticles, and then modifies the titanium-based quantum dots to obtain a particle size of 2-6nm. The particles have obvious fluorescent properties and synergistically act with surfactants. The prepared water-locking agent can migrate deeply without damaging the reservoir, can reduce the surface tension of deionized water to 19.3mN / m, and exhibits excellent water-locking performance. BRIEF DESCRIPTION OF THE DRAWINGS
[0033] Figure 1 This is a high-resolution transmission electron microscope image of titanium quantum dot nanoparticles.
[0034] Figure 2 This is the particle size distribution diagram of titanium quantum dot nanoparticles.
[0035] Figure 3 It is the fluorescence phenomenon of titanium quantum dot nanofluid. DETAILED DESCRIPTION
[0036] Example 1
[0037] 1. A titanium-based quantum dot nanocomposite high-performance water-locking agent, comprising the following raw materials by weight, calculated as 100%, as follows: 0.03% amphiphilic titanium quantum dots, 0.3% amphoteric surfactant oleamidopropyl betaine, 0.1% anionic surfactant sodium lauryl polyoxyethylene ether carboxylate, 0.1% cosolvent glycerin, 0.2% foam suppressant polyoxyethylene polyoxypropanolamine ether, and the balance deionized water;
[0038] Wherein, the amphiphilic titanium quantum dots are prepared by the following method:
[0039] (1) Under stirring, 8 mL of tetraisopropyl titanate was added dropwise to 4 mL of 25 wt% glacial acetic acid aqueous solution and stirred to obtain solution A. Solution A and 1 g of polyethylene glycol 2000 were dissolved in 100 mL of ethanol, stirred evenly, and transferred to a polytetrafluoroethylene high-temperature and high-pressure reactor. The reaction was carried out at 150 ° C for 3 h, washed with anhydrous ethanol 3 times, filtered through a 3 kDa dialysis bag 5 times, each filtration time was 5 h and the water was changed, and then dried at 50 ° C for 18 h to obtain titanium-based quantum dot nanopowder;
[0040] (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nanopowder was added to 90 mL of an 80 wt% ethanol aqueous solution, 20 wt% ammonia aqueous solution was added dropwise to adjust the pH to 10, 10 mL of an ethanol solution containing 0.3 g of 3-aminopropyltrimethoxysilane was added dropwise thereto, and the mixture was refluxed at 55 ° C for 14 h. After the reaction was completed, the mixture was extracted with petroleum ether 3 times and dried at 60 ° C for 12 h to obtain silane coupling agent-modified titanium-based quantum dot nanopowder;
[0041] (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nanopowder and 1 g of dispersant Tween 60 were added to 40 g of deionized water, and 0.05 g of octadecyl methacrylate, 0.1 g of acrylic acid, and 0.05 g of 2-acrylamide-2-methylpropanesulfonic acid were added thereto in sequence. Deionized water was added to a total mass of 100 g of the solution, and the pH was adjusted to 7.5 using a 2 wt % aqueous solution of sodium hydroxide. 2 mL of an aqueous solution containing 0.04 g of potassium persulfate was added thereto, and the mixture was stirred evenly. The mixture was refluxed at 50° C. for 5 h, extracted with ethyl acetate, and dried at 50° C. for 18 h to obtain amphiphilic titanium quantum dots.
[0042] 2. The titanium-based quantum dot nanocomposite high-performance water-locking agent is prepared as follows: at room temperature, under ultrasonication and stirring, amphiphilic titanium quantum dots are uniformly dispersed in water. A cosolvent is then added to the water under stirring. After uniform stirring, an amphoteric surfactant, an anionic nonionic surfactant, and a foam suppressant are sequentially added and stirred until dissolved. The ultrasonic power is 300W.
[0043] Example 2
[0044] The content of amphiphilic titanium quantum dots was 0.05%, and the rest was the same as in Example 1.
[0045] Example 3
[0046] The content of amphiphilic titanium quantum dots was 0.07%, and the rest was the same as in Example 1.
[0047] Example 4
[0048] The content of amphiphilic titanium quantum dots was 0.1%, and the rest was the same as in Example 1.
[0049] Example 5
[0050] 1. A titanium-based quantum dot nanocomposite high-performance water-locking agent, comprising the following raw materials by weight, calculated as 100%, as follows: 0.05% amphiphilic titanium quantum dots; 0.4% amphoteric surfactant oleamidopropylhydroxysulfonic acid betaine; 0.2% anionic nonionic surfactant fatty alcohol polyoxyethylene ether sulfonate; 0.2% cosolvent isopropyl alcohol; 0.3% antifoaming agent polyoxyethylene polyoxypropylene pentaerythritol ether; and the balance deionized water.
[0051] Wherein, the amphiphilic titanium quantum dots are prepared by the following method:
[0052] (1) Under stirring, 5 mL of tetraisopropyl titanate was added dropwise to 4 mL of 5 wt% hydrochloric acid aqueous solution and stirred to obtain solution A. Solution A and 0.8 g of polyethylene glycol 2000 were dissolved in 100 mL of ethanol, stirred evenly, and transferred to a polytetrafluoroethylene high-temperature and high-pressure reactor. The reaction was carried out at 130 ° C for 4 h, washed with anhydrous ethanol 3 times, centrifuged and filtered at a speed of 6000 rpm, and then dried at 48 ° C for 18 h to obtain titanium-based quantum dot nanopowders.
[0053] (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nanopowder was added to 90 mL of an 85 wt% ethanol aqueous solution, 25 wt% ammonia aqueous solution was added dropwise to adjust the pH to 10, 10 mL of an ethanol solution containing 0.2 g of vinyltrimethoxysilane was added dropwise thereto, and the mixture was refluxed at 50 ° C for 18 h. After the reaction was completed, the mixture was extracted with petroleum ether 3 times and dried at 48 ° C for 18 h to obtain silane coupling agent-modified titanium-based quantum dot nanopowder;
[0054] (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nanopowder and 0.8 g of dispersant Tween 80 were added to 40 g of deionized water, and 0.03 g of dodecyldimethylallyl ammonium chloride, 0.09 g of acrylic acid, and 0.03 g of vinylbenzenesulfonic acid were added thereto in sequence. Deionized water was added to a total mass of 100 g of the solution, and the pH was adjusted to 7 using a 5 wt % aqueous sodium hydroxide solution. 2 mL of an aqueous solution containing 0.03 g of ammonium sulfite was then added thereto, and the mixture was stirred evenly. The mixture was refluxed at 60 ° C for 3 h, extracted with ethyl acetate, and dried at 48 ° C for 18 h to obtain amphiphilic titanium quantum dots.
[0055] 2. The preparation method of the titanium-based quantum dot nanocomposite high-performance water-desorption and locking agent is the same as that in Example 1.
[0056] Example 6
[0057] 1. A titanium-based quantum dot nanocomposite high-performance water-locking agent, comprising the following raw materials by weight, calculated as 100%: 0.1% amphiphilic titanium quantum dots, 0.2% amphoteric surfactant hexadecyl hydroxysulfobetaine, 0.05% anionic nonionic surfactant sodium lauryl polyoxyethylene ether sulfate, 0.15% cosolvent methanol, 0.1% foam suppressor polyoxypropylene glycerol ether, and the balance deionized water;
[0058] Wherein, the amphiphilic titanium quantum dots are prepared by the following method:
[0059] (1) Under stirring, 8 mL of tetraisopropyl titanate was added dropwise to 4 mL of 20 wt% lactic acid aqueous solution and stirred to obtain solution A. Solution A and 1.2 g of polyethylene glycol 2000 were dissolved in 100 mL of ethanol, stirred evenly, and transferred to a polytetrafluoroethylene high-temperature and high-pressure reactor. The reaction was carried out at 180 ° C for 2 h, washed with anhydrous ethanol 3 times, filtered through a 3 kDa dialysis bag 4 times, each filtration time was 6 h and the water was changed, and then dried at 60 ° C for 12 h to obtain titanium-based quantum dot nanopowder;
[0060] (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nanopowder was added to 90 mL of an 80 wt% ethanol aqueous solution, 20 wt% ammonia aqueous solution was added dropwise to adjust the pH to 10, 10 mL of an ethanol solution containing 0.3 g of γ-methacryloyloxypropyltrimethoxysilane was added dropwise thereto, and the mixture was refluxed at 60° C. for 12 h. After the reaction was completed, the mixture was extracted with petroleum ether three times and dried at 60° C. for 12 h to obtain silane coupling agent-modified titanium-based quantum dot nanopowder;
[0061] (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nanopowder and 1.5 g of dispersant Tween 80 were added to 40 g of deionized water, and 0.05 g of octadecyldimethylallyl ammonium chloride, 0.1 g of acrylic acid, and 0.05 g of N-vinylpyrrolidone were added thereto in sequence. Deionized water was added to a total mass of 100 g of the solution, and the pH was adjusted to 8 using a 2 wt % aqueous solution of sodium hydroxide. 2 mL of an aqueous solution containing 0.03 g of hydrogen peroxide was added thereto, and the mixture was stirred evenly. The mixture was refluxed at 55 ° C for 4 h, extracted with ethyl acetate, and dried at 60 ° C for 12 h to obtain amphiphilic titanium quantum dots.
[0062] 2. The preparation method of the titanium-based quantum dot nanocomposite high-performance water-desorption and locking agent is the same as that in Example 1.
[0063] Example 7
[0064] 1. A titanium-based quantum dot nanocomposite high-performance water-locking agent, comprising the following raw materials by weight, calculated as 100%: 0.03% amphiphilic titanium quantum dots, 0.3% amphoteric surfactant erucamidopropyl betaine, 0.05% anionic nonionic surfactant sodium lauryl polyoxyethylene ether carboxylate, 0.1% cosolvent propylene glycol, 0.1% antifoaming agent polyoxyethylene polyoxypropanolamine ether, and the balance deionized water;
[0065] Wherein, the amphiphilic titanium quantum dots are prepared by the following method:
[0066] (1) Under stirring, 6 mL of tetraisopropyl titanate was added dropwise to 4 mL of 1 wt% hydrochloric acid aqueous solution and stirred to obtain solution A. Solution A and 1 g of polyethylene glycol 2000 were dissolved in 100 mL of ethanol, stirred evenly, and transferred to a polytetrafluoroethylene high-temperature and high-pressure reactor. The reaction was carried out at 150 ° C for 3 h, washed with anhydrous ethanol 3 times, centrifuged and filtered at a speed of 8000 rpm, and then dried at 50 ° C for 18 h to obtain titanium-based quantum dot nanopowders.
[0067] (2) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 2 g of the titanium-based quantum dot nanopowder was added to 90 mL of an 80 wt% ethanol aqueous solution, 20 wt% ammonia aqueous solution was added dropwise to adjust the pH to 10, 10 mL of an ethanol solution containing 0.2 g of N-aminoethyl-3-aminopropyltriethoxysilane was added dropwise thereto, and the mixture was refluxed at 60° C. for 14 h. After the reaction was completed, the mixture was extracted with petroleum ether three times and dried at 60° C. for 12 h to obtain silane coupling agent-modified titanium-based quantum dot nanopowder;
[0068] (3) Under ultrasonic treatment with an ultrasonic power of 300 W and simultaneous stirring, 1 g of the silane coupling agent-modified titanium-based quantum dot nanopowder and 1 g of dispersant Tween 60 were added to 40 g of deionized water, and 0.05 g of tetradecyldimethylallyl ammonium chloride, 0.1 g of acrylic acid, and 0.05 g of acryloylmorpholine were added thereto in sequence. Deionized water was added to a total mass of 100 g of the solution, and the pH was adjusted to 7.5 using a 2 wt % aqueous solution of sodium hydroxide. 2 mL of an aqueous solution containing 0.04 g of ammonium sulfite was added thereto, and the mixture was stirred evenly. The mixture was refluxed at 50° C. for 5 h, extracted with ethyl acetate, and dried at 50° C. for 18 h to obtain amphiphilic titanium quantum dots.
[0069] 2. The preparation method of the titanium-based quantum dot nanocomposite high-performance water-desorption and locking agent is the same as that in Example 1.
[0070] Comparative Example 1
[0071] The content of amphiphilic titanium quantum dots is 0, and the rest is the same as in Example 1.
[0072] Performance testing
[0073] 1. Detection of Amphiphilic Titanium Quantum Dots in Example 1
[0074] 1. Transmission electron microscopy
[0075] The amphiphilic titanium quantum dots in Example 1 were examined by transmission electron microscopy. Figure 1 .
[0076] 2. Particle size detection
[0077] The particle size of the amphiphilic titanium quantum dots in Example 1 was calculated using Image J software. Figure 2 .
[0078] Depend on Figure 1 、 2 As shown, the synthesized titanium quantum dots are granular, have good dispersion, uniform size distribution, and a median particle size of 3.5 nm.
[0079] 3. Fluorescence property detection
[0080] The fluorescence characteristics of the amphiphilic titanium quantum dots in Example 1 were detected using a dark box UV instrument. The results are shown in Figure 3 .Depend on Figure 3 It can be seen that it exhibits typical blue fluorescence characteristics, confirming that it is a quantum dot nanofluid.
[0081] 2. Surface tension test of water lock agent
[0082] At room temperature, the surface tension of the sample was measured using the hanging drop method module of a high-temperature and high-pressure interfacial tension meter. The water-locking agent sample was sucked into a syringe, and a drop of liquid was ejected and suspended in the air. The surface tension was calculated by fitting the drop shape, and the value was taken after the curve stabilized. The test results are shown in Table 1.
[0083] Table 1 Surface tension test results
[0084] Water lock agent Amphiphilic titanium quantum dots concentration / % Surface tension / mN / m Comparative Example 1 0 27.2 Example 1 0.03 21.5 Example 2 0.05 20.1 Example 3 0.07 19.3 Example 4 0.1 19.4 Example 5 0.05 19.1 Example 6 0.1 19.3 Example 7 0.03 20.5
[0085] From the data in Table 1, it can be seen that the surface tension of the liquid is significantly reduced after adding amphiphilic titanium quantum dots. Compared with not adding amphiphilic titanium quantum dots, when the addition amount of amphiphilic titanium quantum dots in Example 3 reaches 0.07%, the surface tension is reduced from 27.2 mN / m to 19.3 mN / m. It can be seen that amphiphilic titanium quantum dots can cooperate with surfactants to exert excellent water-locking effect.
Claims
1. A titanium-based quantum dot nanocomposite high-performance water-locking agent, characterized by: Based on 100%, it is composed of the following raw materials in weight content: 0.03-0.1% of amphiphilic titanium quantum dots, 0.2-0.4% of amphoteric surfactant, 0.05-0.2% of anionic nonionic surfactant, 0.1-0.2% of cosolvent, 0.1-0.3% of antifoaming agent, and the balance of water; The amphiphilic titanium quantum dots are prepared by the following method: first, a titanate coupling agent is hydrolyzed and condensed by a hydrothermal method to form titanium-based quantum dots, then modified by a silane coupling agent, and then a secondary surface in-situ polymerization modification is performed using a functional monomer, as follows: (1) Under stirring, a titanate coupling agent is added dropwise to an activator and stirred to obtain solution A. Solution A and polyethylene glycol 2000 are dissolved in ethanol, stirred evenly, reacted at 130-180°C for 2-4 hours, washed with anhydrous ethanol, filtered, and dried to obtain titanium-based quantum dot nanopowders; (2) Under ultrasonic and stirring conditions, the titanium-based quantum dot nanopowder is added to an ethanol aqueous solution, the pH is adjusted to 10, an ethanol solution of a silane coupling agent is added dropwise thereto, and the mixture is refluxed at 50-60° C. for 12-18 hours. After the reaction is completed, the mixture is extracted with petroleum ether and dried to obtain a silane coupling agent-modified titanium-based quantum dot nanopowder; (3) Under ultrasonic and stirring conditions, the silane coupling agent-modified titanium-based quantum dot nanopowder and dispersant are added to deionized water, the functional monomer is added thereto, the pH is adjusted to 7-8, and then an aqueous solution of the initiator is added thereto, the mixture is stirred evenly, refluxed at 50-60° C. for 3-5 hours, extracted with ethyl acetate, and dried to obtain amphiphilic titanium quantum dots; The functional monomers are hydrophobic monomers, acrylic acid and heat-resistant and salt-resistant monomers; based on the total mass of the functional monomers being 100%, the addition ratios of the hydrophobic monomers, acrylic acid and heat-resistant and salt-resistant monomers are 20-25%: 50-60%: 20-25%; The hydrophobic monomer is any one of dodecyldimethylallyl ammonium chloride, tetradecyldimethylallyl ammonium chloride, hexadecyldimethylallyl ammonium chloride, octadecyldimethylallyl ammonium chloride, and octadecyl methacrylate; The temperature-resistant and salt-resistant monomer is at least one of 2-acrylamide-2-methylpropanesulfonic acid, vinylbenzenesulfonic acid, vinylsulfonic acid, N-vinylpyrrolidone, and acryloylmorpholine.
2. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 1, characterized in that: In step (1), the ratio of titanate coupling agent, activator, polyethylene glycol 2000, and ethanol is (5-8) mL:4 mL: (0.8-1.2) g:100 mL; The titanate coupling agent is one of tetraisopropyl titanate or n-butyl titanate; the activator is a 1-5wt% hydrochloric acid aqueous solution, a 20-25wt% glacial acetic acid aqueous solution, or a 20-25wt% lactic acid aqueous solution.
3. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 2, characterized in that: In step (2), the mass of the silane coupling agent is 10-15% of the mass of the titanium-based quantum dot nanopowder; The silane coupling agent is any one of vinyltrimethoxysilane, vinyltriethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ-methacryloxypropyltriethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, N-aminoethyl-3-aminopropyltriethoxysilane, and N-aminoethyl-3-aminopropyltrimethoxysilane; The ethanol content in the ethanol aqueous solution is 80-85wt%.
4. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 3, characterized in that: In step (3), the mass of the functional monomer accounts for 15-20% of the mass of the silane coupling agent modified titanium-based quantum dot nanopowder, the mass of the initiator accounts for 15-20% of the mass of the functional monomer, and the mass of the dispersant accounts for 0.8-1.5% of the total mass of the silane coupling agent modified titanium-based quantum dot nanopowder, deionized water, and the functional monomer; The dispersant is any one of Tween 20, Tween 60, Tween 80, and dodecyl polyoxyethylene ether; The initiator is any one or two of ammonium persulfate, ammonium sulfite, potassium persulfate, potassium sulfite, sodium persulfate, sodium sulfite, and hydrogen peroxide.
5. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 4, characterized in that: The drying step is drying at 48-60° C. for 12-18 hours; the ultrasonic power is 300 W; in step (2), a 20-25 wt % ammonia solution is added dropwise to adjust the pH to 10; in step (3), a 2-5 wt % sodium hydroxide solution is added dropwise to adjust the pH to 7-8; and in step (1), the filtration step is dialysis or centrifugation.
6. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 1, characterized in that: The amphoteric surfactant is any one of oleamidopropyl betaine, oleamidopropyl hydroxysulfobetaine, hexadecyl hydroxysulfobetaine, hexadecyl propyl betaine, erucamidopropyl betaine, and erucamidopropyl hydroxysulfobetaine; The anionic-nonionic surfactant is any one of sodium lauryl polyoxyethylene ether sulfate, fatty alcohol polyoxyethylene ether sulfonate, and sodium lauryl polyoxyethylene ether carboxylate.
7. The titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 1, characterized in that: The foam suppressant is any one of polyoxyethylene polyoxypropylene pentaerythritol ether, polyoxyethylene polyoxypropanolamine ether, and polyoxypropylene glycerol ether; The co-solvent is at least one of isopropyl alcohol, methanol, propylene glycol and glycerol.
8. The method for preparing a titanium-based quantum dot nanocomposite high-performance water-locking agent according to claim 1, characterized in that: At room temperature, under ultrasonic and stirring conditions, the amphiphilic titanium quantum dots are evenly dispersed in water, and then a cosolvent is added thereto under stirring. After stirring evenly, an amphoteric surfactant, an anionic-nonionic surfactant, and an antifoaming agent are added thereto in sequence and stirred until dissolved.