A nano-silica modified polymer type asphaltene inhibitor and a preparation method and application thereof

Abstract

The application discloses a polymer type asphaltene inhibitor based on nano-silica modification and a preparation method and application thereof, and comprises the following steps: firstly, surface organic silica is obtained by condensation reaction of a silica dispersion liquid and a coupling agent solution; secondly, an organic solvent, the surface organic silica and an unsaturated alkyl ester monomer are uniformly mixed, and then an initiator is added for reaction; after the reaction is completed, a sulfonic group-containing organic monomer and a cocatalyst are added in sequence for continuous reaction; after the reaction is completed, a terminating agent is added into the reaction system to terminate the reaction; and finally, the polymer type asphaltene inhibitor based on nano-silica modification is obtained after washing, filtering and drying. The asphaltene inhibitor prepared by the application has obvious dispersing and stabilizing effect on crude oil asphaltene.

Description

Technical Field

[0001] This invention belongs to the field of flow modifiers in the petroleum weather storage and transportation industry, specifically relating to a polymer-type asphaltene inhibitor based on nano-silica modification, its preparation method, and its application. Background Technology

[0002] During crude oil gathering, transportation, and pipeline transport, temperature and pressure fluctuations, shearing forces, and the loss of light components weaken colloidal stability, causing asphaltene to transform from a dispersed state to a flocculated and aggregated state. With long-term storage in underground water-sealed caverns, once asphaltene deposits, it can lead to increased pressure drop, higher energy consumption, and localized blockages in subsequent pipeline transport, affecting pipeline safety and continuous operation.

[0003] Compared to energy-intensive methods such as dilution and heating, adding asphaltene inhibitors during storage in underground water-sealed caverns offers engineering advantages such as operational flexibility and rapid response. However, when polymers are added to crude oil as asphaltene inhibitors, they are susceptible to shear degradation during pipeline transportation. Strong shearing occurs at pipeline pumps, valves, throttling points, and bends, leading to chain breakage in some polymers and a decrease in molecular weight, resulting in reduced dispersion ability. Furthermore, they exhibit poor persistence, and degradation fragments may alter the emulsion state or cause secondary problems.

[0004] Compared with traditional small molecule dispersants, nano-inhibitors often require lower dosages, have stronger temperature and salt resistance and shear resistance, and can achieve better compatibility and persistence in different crude oil systems by controlling particle size, surface hydrophilicity-hydrophobicity balance and functional group type. This provides a more promising material solution for preventing sedimentation and improving pipeline pressure reduction efficiency in underground water-sealed cavern storage. Summary of the Invention

[0005] This invention is proposed to solve the problems existing in the prior art, and its purpose is to provide a polymer-type asphaltene inhibitor based on nano-silica modification, its preparation method and application.

[0006] This invention is achieved through the following technical solution: A method for preparing a polymer-type asphaltenes inhibitor based on nano-silica modification includes the following steps: S1. Preparation of surface-organized silica: Vacuum-dried nano-silica is dispersed in a certain amount of dispersion carrier solvent and sonicated for 30 min to 60 min to make the nano-silica uniformly dispersed in the dispersion carrier solvent, thus obtaining a silica dispersion. Take a certain amount of coupling agent solvent, add silane coupling agent to it, adjust the pH of the solution to 4-5, stir at room temperature for 0.5 h-2 h, and carry out silane hydrolysis reaction. After the hydrolysis reaction is completed, the silane hydrolysis reaction completed solution is obtained. Add silica dispersion to the silane hydrolysis reaction completed solution and stir at 80 ℃~180 ℃ for 24 h. The silane coupling agent that is completely hydrolyzed in the silane hydrolysis reaction completed solution undergoes a condensation reaction with the silanol groups on the silica surface. After the condensation reaction, solid-liquid separation (centrifugation) was performed using anhydrous ethanol, followed by washing the solid with anhydrous ethanol. Finally, the byproducts were washed using a regenerated cellulose dialysis bag (a small amount of silane coupling agent that did not undergo condensation reaction will self-polymerize). The volume of the dialysis fluid (distilled water or ethanol) was 100 times the volume of the solid product. The fluid was continuously stirred and washed for 24 hours, changing the solution every 4 to 6 hours, until there was no obvious silane odor. After vacuum drying at 70 °C, surface-organized silica (o-SiO2) was obtained. The process of preparing surface-organized silica in this invention not only greatly improves the dispersibility of silica in the organic phase, but more importantly, introduces polymerizable functional groups into it. The particle size of the nano-silica is 10 nm to 100 nm; The dispersion carrier solvent and coupling agent solvent are both mixed solutions of methyl isopropanone and water or anhydrous ethanol and water, with a volume ratio of methyl isopropanone to water of 95:5; and a volume ratio of anhydrous ethanol to water of 95:5. The silane coupling agent is any one of γ-methacryloxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, or a diekoxy class; The concentration of the nano-silica in the dispersion carrier solvent is 50 g / L to 100 g / L; The mass concentration of the silane coupling agent in the coupling agent solvent is 2 wt%~10 wt%; The mass of the silane coupling agent is 5wt% to 15wt% of the mass of nano-silica; S2, Synthetic Asphaltenes Inhibitor: In a four-necked flask, add organic solvent, surface-organized silica (o-SiO2) prepared in step S1 and unsaturated alkyl ester monomer. Under an inert atmosphere, stir magnetically until uniformly dispersed. Add initiator and react at 60 ℃~75 ℃ for 6 h~12 h to make the silica surface hydrophobic, easier to disperse in the oil phase and less prone to water absorption. After the reaction is complete, a solution of organic monomers containing sulfonic acid groups and a co-catalyst are added sequentially, and the temperature is adjusted to 50 ℃~75 ℃, and the reaction is carried out for 4 h~12 h. The mass ratio of the organic solvent, surface-organized silica (o-SiO2), and unsaturated alkyl ester monomer is 50 mL: (1~2) g: (1~3) g; The organic solvent is any one of toluene, DMF, ethyl acetate or DMSO; The unsaturated alkyl ester monomer has 6 to 18 carbon atoms in its alkyl side chain and 1 to 3 unsaturated bonds; the unsaturated alkyl ester monomer is any one of dodecyl acrylate, hexadecyl acrylate, or octadecyl acrylate. The initiator is any one of AIBN, BPO or APS; The amount of the initiator added is 0.5w% to 1.5w% of the total amount of unsaturated alkyl ester monomers and sulfonic acid group-containing organic monomers. The sulfonic acid-containing organic monomer is any one of 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 2-methacrylamido-2-methylpropanesulfonic acid (MAPS), 2-sulfoethyl acrylate (SEA), or 3-sulfopropyl acrylate (SPA). The amount of the organic monomer containing sulfonic acid group added is 10% to 30% of the mass of the unsaturated alkyl ester monomer; the solvent used for the organic monomer solution containing sulfonic acid group is 10 mL of anhydrous ethanol; The co-catalyst is at least one of ammonium persulfate, potassium persulfate, or tetramethylethylenediamine; The mass of the co-catalyst added is 0.2g; S3, Post-treatment with asphaltene inhibitors: After the reaction in step S2 is completed, a terminator solution is added to the reaction system to terminate the reaction. After washing with an alcohol solvent multiple times, the mixture is filtered and dried under vacuum at 50℃~75℃ to finally obtain a polymer-type asphaltenes inhibitor with a "core-shell" structure based on nano-silica modification. The terminator is p-hydroxyanisole (MEHQ). The solvent for the terminating agent solution is a mixture of acetone and ethanol in a volume ratio of 1:1; The concentration of the terminator in the terminator solution is 200ppm to 500ppm; The alcohol solvent is anhydrous ethanol.

[0007] A polymeric asphaltenes inhibitor based on nano-silica modification prepared by the aforementioned method, wherein the asphaltenes inhibitor is a core-shell structured nanocomposite material with organically modified nano-silica as the core and sulfonated polyunsaturated ester as the shell, wherein polymer chains are chemically grafted onto the surface of organically modified nano-silica particles via covalent bonds.

[0008] The application of a polymer-type asphaltene inhibitor based on nano-silica modification prepared by the aforementioned method in preventing asphaltene deposition and blockage during crude oil storage in underground water-sealed caverns; the amount of asphaltene inhibitor added is 200ppm~500ppm.

[0009] The beneficial effects of this invention are: This invention provides a polymer-type asphaltenes inhibitor based on nano-silica modification, its preparation method, and its application. The prepared asphaltenes inhibitor is added to crude oil stored in underground water-sealed caverns to inhibit asphaltenes precipitation and sedimentation, reduce the risk of crude oil deterioration and stratification, and ensure the normal operation of the equipment.

[0010] This invention uses nano-silica as a base, chemically modifying it to impart reactivity, resulting in functional composite nano-silica. Using nano-silica as a nanocore, silanization condensation transforms it into a polymerization "anchor," enabling copolymerization with acrylates, enhancing their lipophilicity, and allowing for uniform dispersion in the oil phase. Furthermore, an initiator facilitates free radical copolymerization of acrylates with sulfonic acid-containing organic monomers, allowing copolymer chains to grow on the particle surface, forming composite nanoparticles with a stable "core-shell" structure. The introduction of sulfonic acid groups enhances their interaction with asphaltenes in crude oil, achieving three major advantages: high performance, low cost, and environmental friendliness. This process inhibits asphaltenes flocculation and enhances the dispersion stability of asphaltenes in crude oil. The raw materials used in this invention are environmentally friendly and inexpensive, the process is simple, and the resulting product exhibits excellent effects in inhibiting asphaltenes deposition in crude oil.

[0011] This invention uses widely available and inexpensive silica to replace traditional synthetic nanomaterials, significantly reducing raw material costs. It aligns with the development direction of green chemistry, is environmentally friendly, and has low cost. This invention breaks the inherent hydrophilic barrier of silica through chemical modification, making it perfectly compatible with oils and polyolefin matrices, avoiding performance defects caused by agglomeration, and giving asphaltenes inhibitors excellent compatibility and dispersibility. The preparation method of this invention has high process feasibility and is easy to scale up for production. Attached Figure Description

[0012] Figure 1 This is the Fourier transform infrared spectrum of the polymer-type asphaltenes inhibitor based on nano-silica modification prepared in Example 1 of this invention.

[0013] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0014] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0015] Example 1

[0016] A method for preparing a polymer-type asphaltenes inhibitor based on nano-silica modification includes the following steps: S1. Preparation of surface-organized silica: 10g of nano-silica with a particle size of 20nm, which was vacuum dried at 120℃ for 4h, was dispersed in 200mL of a mixture of anhydrous ethanol and water (the volume ratio of anhydrous ethanol to water was 95 / 5), and sonicated for 30min to make it uniformly dispersed, thus obtaining a silica dispersion. Take another 0.5 g of γ-methacryloxypropyltrimethoxysilane and add it to 20 mL of a mixture of anhydrous ethanol and water (the volume ratio of anhydrous ethanol to water is 95 / 5). Adjust the pH to 4 with glacial acetic acid and stir at room temperature for 0.5 h to carry out the silane hydrolysis reaction. After the hydrolysis reaction is completed, the silane hydrolysis reaction completed solution is obtained. Add silica dispersion to the silane hydrolysis reaction solution, stir for 30 min, and then continue the reaction in a water bath at 80 °C for 24 h under a nitrogen atmosphere. After the reaction is completed, separate the solution, wash with ethanol 3 times, then wash with water 2 times, and finally remove unreacted silane and byproducts by dialysis with regenerated cellulose. Then dry under vacuum at 70 °C for 24 h to obtain surface organic silica (o-SiO2). S2, Synthetic Asphaltenes Inhibitor: In a four-necked flask, add 100 mL of DMF, 2 g of surface-organic silica (o-SiO2) prepared in step S1 and 6 g of octadecyl acrylate. Under a nitrogen atmosphere, stir magnetically to disperse the silica evenly. Add 0.11 g of initiator AIBN and react at 70 °C for 6 h to make the silica surface hydrophobic, easier to disperse in the oil phase and less prone to water absorption. After the reaction was completed, AMPS solution (1.8 g of AMPS dissolved in 10 mL of ethanol) and 0.2 g of co-catalyst ammonium persulfate were added sequentially, the temperature was adjusted to 70 °C, and the reaction was allowed to proceed for 10 h. S3, Post-treatment with asphaltene inhibitors: After the reaction in step S2 is completed, 10 mL of terminator solution (the solvent of the terminator solution is a mixture of acetone and ethanol in a volume ratio of 1:1) is added to the reaction system to terminate the reaction. The solid particles are centrifuged, washed multiple times with anhydrous ethanol using a Soxhlet extractor, filtered, and dried under vacuum at 60 °C to finally obtain a polymer-type asphaltene inhibitor (sample A) with a "core-shell" structure based on nano-silica modification.

[0017] The Fourier transform infrared spectrum of the prepared polymer-type asphaltenes inhibitor based on nano-silica modification is shown below. Figure 1 As shown, from Figure 1 It can be seen that: 3428cm -1 The strong absorption peak at 1089 cm⁻¹ is attributed to the silanol groups (Si-OH) on the silica surface, and may also be superimposed with -NH groups. -1 The absorption peak at 1298 cm⁻¹ is attributed to the asymmetric stretching of Si-O-Si.-1 One of the core fingerprint peaks of AMPS, attributed to -SO3 - The S=O asymmetric stretching, and at 954cm -1 The second core fingerprint peak is attributed to -SO3. - The S=O symmetrical stretching vibration. 1733cm -1 The absorption peak at 2811 cm⁻¹ corresponds to the C=O group in the acrylate. -1 and 1483cm -1 This is attributed to the stretching and bending vibrations of its alkyl groups, indicating successful modification of nano-silica.

[0018] Example 2

[0019] A method for preparing a polymer-type asphaltenes inhibitor based on nano-silica modification includes the following steps: S1. Preparation of surface-organized silica: 10g of nano-silica with a particle size of 50nm, which was vacuum dried at 120℃ for 4h, was dispersed in 200mL of a mixture of anhydrous ethanol and water (the volume ratio of anhydrous ethanol to water was 95 / 5), and sonicated for 30min to make it uniformly dispersed, thus obtaining a silica dispersion. Take another 0.5 g of vinyltris(β-methoxyethoxy)silane and add it to a mixture of 20 mL of anhydrous ethanol and water (the volume ratio of anhydrous ethanol to water is 95 / 5). Adjust the pH to 4 with glacial acetic acid and stir at room temperature for 30 min to carry out the silane hydrolysis reaction. After the silane hydrolysis reaction is completed, a silica dispersion is added to the silane hydrolysis reaction solution. After stirring for 30 min, the reaction is continued in a water bath at 100 °C for 24 h under a nitrogen atmosphere. After the reaction is completed, the solution is separated, washed three times with ethanol, and then washed twice with water to remove unreacted silane and byproducts. The solution is then dried under vacuum at 60 °C for 24 h to obtain surface-organic silica (o-SiO2). S2, Synthetic Asphaltenes Inhibitor: In a four-necked flask, add 100 mL of DMF, 4 g of surface-organic silica (o-SiO2) prepared in step S1, and 6 g of octadecyl acrylate. Under a nitrogen atmosphere, stir magnetically to disperse the silica evenly. Add 0.1 g of initiator AIBN and react at 70 °C for 6 h to make the silica surface hydrophobic, easier to disperse in the oil phase, and less prone to water absorption. After the reaction was completed, AMPS solution (1.8 g of AMPS dissolved in 10 mL of ethanol) and the co-catalyst ammonium persulfate were added sequentially, the temperature was adjusted to 70 °C, and the reaction was allowed to proceed for 10 h. S3, Post-treatment with asphaltene inhibitors: After the reaction in step S2 is completed, 10 mL of a terminator (a 1:1 mixture of acetone and ethanol) is added to the reaction system to terminate the reaction. The solid particles are centrifuged, washed multiple times with anhydrous ethanol using a Soxhlet extractor, filtered, and dried under vacuum at 60 °C to finally obtain a polymer-type asphaltene inhibitor with a "core-shell" structure based on nano-silica modification.

[0020] Example 3

[0021] A method for preparing a polymer-type asphaltenes inhibitor based on nano-silica modification includes the following steps: S1. Preparation of surface-organized silica: 10g of nano-silica with a particle size of 20nm, which was vacuum dried at 120℃ for 4h, was dispersed in 200mL of a mixture of anhydrous ethanol and water (the volume ratio of anhydrous ethanol to water was 95 / 5), and sonicated for 30min to make it uniformly dispersed, thus obtaining a silica dispersion. Take another 0.5 g of γ-methacryloxypropyltriethoxysilane and add it to a mixture of 20 mL of anhydrous ethanol and water (the volume ratio of anhydrous ethanol to water is 95 / 5). Adjust the pH to 4 with glacial acetic acid and stir at room temperature for 30 min to carry out the silane hydrolysis reaction. After the silane hydrolysis reaction is completed, a silica dispersion is added to the silane hydrolysis reaction solution. After stirring for 30 min, the reaction is continued in a water bath at 120 °C for 24 h under a nitrogen atmosphere. After the reaction is completed, the solution is separated, washed three times with ethanol, and then washed twice with water to remove unreacted silane and byproducts. The solution is then dried under vacuum at 60 °C for 24 h to obtain surface-organic silica (o-SiO2). S2, Synthetic Asphaltenes Inhibitor: In a four-necked flask, add 100 mL of DMF, 4 g of surface-organic silica (o-SiO2) prepared in step S1 and 4 g of octadecyl acrylate. Under a nitrogen atmosphere, stir magnetically to disperse the silica evenly. Add 0.07 g of initiator AIBN and react at 70 °C for 6 h to make the silica surface hydrophobic, easier to disperse in the oil phase and less prone to water absorption. After the reaction was completed, AMPS solution (1.2 g of AMPS dissolved in 10 mL of ethanol) and the co-catalyst ammonium persulfate were added sequentially, the temperature was adjusted to 70 °C, and the reaction was allowed to proceed for 10 h. S3, Post-treatment with asphaltene inhibitors: After the reaction in step S2 is completed, 10 mL of a terminator (a 1:1 mixture of acetone and ethanol) is added to the reaction system to terminate the reaction. The solid particles are centrifuged, washed multiple times with anhydrous ethanol using a Soxhlet extractor, filtered, and dried under vacuum at 60 °C to finally obtain a polymer-type asphaltene inhibitor with a "core-shell" structure based on nano-silica modification.

[0022] Examples 1-3 of this invention all yielded asphaltenes inhibitors, which showed significant effects on the dispersion stability of crude oil asphaltenes. The performance of the composite nano-silica asphaltenes inhibitors prepared in Examples 1-3 is studied below: The asphaltene inhibitors prepared in Examples 1-3 were vacuum dried, and then dispersed in diesel fuel at a mass ratio of 1:10. The mixture was ultrasonicated for 20 minutes until uniformly dispersed, yielding asphaltene inhibitor dispersions. The asphaltene inhibitor dispersions obtained in Examples 1-3 were evaluated, and the results are shown in Tables 1 and 2. The testing method is as follows: Currently, there is no unified standard for evaluating asphaltene inhibitors. The evaluation mainly refers to the experimental methods in NB / SH / T 0902-2015 "Determination of the Separability Value of the n-Heptane-Induced Phase in Heavy Fuel Oil Containing Asphaltene by Optical Scanning Method" and NB / SH / T 0908-2015 "Determination of the Stability and Compatibility of Heavy Fuel Oil and Crude Oil by Optical Detection Method" to evaluate the dispersion stability of asphaltene, thereby evaluating asphaltene inhibitors. Static experiments are used for evaluation. By adding n-heptane (an asphaltene precipitant) to crude oil, physical methods (high-speed centrifugation, spectrophotometry, and weighing) are used to quantitatively compare the amount of asphaltene deposition or dispersion stability before and after the addition, quickly determining the inhibitor's effect.

[0023] Absorbance value is positively correlated with the dispersion stability of asphaltene; the higher the absorbance, the better the dispersibility of asphaltene and the better the inhibition effect. The dispersion stability rate is calculated as follows:

[0024] In the formula: Dispersion stability rate / %; A 加剂平均 A represents the average absorbance of the additive; 空白平均 The average absorbance of the blank sample; The experimental results of the asphalt dispersion test (ADT) - spectrophotometry and high-speed centrifugation are shown in Tables 1 and 2.

[0025] Table 1: Asphaltene Dispersion Test (ADT) - Spectrophotometry

[0026] Table 2: High-speed centrifugation method

[0027] As can be seen from the experimental results in Tables 1 and 2, the composite nano-asphaltite inhibitor prepared in this invention not only has strong dispersibility and can reduce the aggregation tendency between particles by adsorbing on the surface of asphaltite particles, thereby improving the dispersion stability of asphaltite in crude oil and reducing precipitation from the source, but also has high inhibition efficiency and can significantly reduce the amount of asphaltite deposition.

[0028] The principle of this invention: There are many methods for surface functionalization of nano-silica, and the implementation process is simpler. It can be optimized for different crude oil components and contents. Nano-silica has a high specific surface area and strong adsorption capacity. This invention is based on polymer-type asphaltenes inhibitor modified with nano-silica. Compared with traditional organic inhibitors, it can better disperse and stabilize asphaltenes in crude oil in terms of mechanism.

[0029] Nanoparticles have strong interactions and are prone to agglomeration and enlargement. Once agglomerated, they lose their nano-effect and the inhibitory effect decreases. Based on this, the present invention performs surface organic modification and reactivity modification on nano-silica to make it into oil-soluble nanoparticles, which enhances the dispersibility of nanoparticles in crude oil. Then, it is chemically grafted with unsaturated acid esters and sulfonated to prepare a crude oil asphaltenes inhibitor that integrates "capture-dispersion-agglomeration inhibition".

[0030] This invention transforms nano-silica from an easily agglomerated, hydrophilic nanoparticle into an oil-soluble monomer that can participate in polymerization reactions by sulfonating it.

[0031] This invention relates to an asphaltenes inhibitor that uses nano-silica as a nanocore. Through silanization condensation, the nano-silica becomes a polymerization "anchor," enabling copolymerization with acrylates, enhancing their lipophilicity, and allowing for uniform dispersion in the oil phase. Furthermore, an initiator facilitates free radical copolymerization of acrylates and AMPS, causing copolymer chains to grow on the particle surface, forming composite nanoparticles with a stable "core-shell" structure. The introduction of sulfonic acid groups further enhances their interaction with asphaltenes in crude oil. This invention achieves three major advantages: high performance, low cost, and environmental friendliness, inhibiting asphaltenes flocculation and enhancing the dispersion stability of asphaltenes in crude oil. The raw materials used in this invention are environmentally friendly and inexpensive, the process is simple, and the resulting product exhibits excellent efficacy in inhibiting asphaltenes deposition in crude oil.

[0032] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A method for preparing a polymer-type asphaltenes inhibitor based on nano-silica modification, characterized in that: Includes the following steps: S1. Nano-silica is uniformly dispersed in a dispersion carrier solvent to obtain a silica dispersion; a silane coupling agent is added to the coupling agent solvent and stirred for hydrolysis to obtain a silane hydrolysis reaction completed solution; the silica dispersion is added to the silane hydrolysis reaction completed solution to carry out a condensation reaction; after the condensation reaction is completed, the surface-organized silica is obtained after solid-liquid separation, washing, dialysis and drying. S2. After mixing the organic solvent, unsaturated alkyl ester monomer and the surface-organized silica obtained in step S1 evenly, an initiator is added to carry out the reaction; after the reaction is completed, a solution of organic monomer containing sulfonic acid groups and a co-catalyst are added in sequence to continue the reaction. After the reactions in steps S3 and S2 are completed, a terminator solution is added to the reaction system to terminate the reaction. After washing, solid-liquid separation and drying, a polymer-type asphaltene inhibitor based on nano-silica modification is obtained.

2. The preparation method of the polymer-type asphaltenes inhibitor based on nano-silica modification according to claim 1, characterized in that: The particle size of the nano-silica is 10 nm to 100 nm; the silane coupling agent is any one of γ-methacryloxypropyltrimethoxysilane, vinyltris(β-methoxyethoxy)silane, or a diekoxy group.

3. The preparation method of the polymer-type asphaltenes inhibitor based on nano-silica modification according to claim 1, characterized in that: The dispersion carrier solvent and coupling agent solvent are both mixed solutions of methyl isopropanone and water or mixed solutions of anhydrous ethanol and water, with a volume ratio of methyl isopropanone to water of 95:5; and a volume ratio of anhydrous ethanol to water of 95:

5.

4. The preparation method of the polymer-type asphaltenes inhibitor based on nano-silica modification according to claim 1, characterized in that: The concentration of the nano-silica in the dispersion carrier solvent is 50 g / L to 100 g / L; The mass concentration of the silane coupling agent in the coupling agent solvent is 2 wt%~10 wt%; The mass of the silane coupling agent is 5wt% to 15wt% of the mass of nano-silica.

5. The preparation method of the polymer-type asphaltenes inhibitor based on nano-silica modification according to claim 1, characterized in that: The organic solvent in step S2 is any one of toluene, DMF, ethyl acetate or DMSO; The unsaturated alkyl ester monomer is any one of dodecyl acrylate, hexadecyl acrylate, or octadecyl acrylate.

6. The preparation method of the polymer-type asphaltenes inhibitor based on nano-silica modification according to claim 1, characterized in that: The ratio of the organic solvent, surface-organized silica, and unsaturated alkyl ester monomer is 50 mL: (1~2) g: (1~3) g; The initiator in step S2 is any one of AIBN, BPO or APS; the mass of the initiator added is 0.5w% to 1.5w% of the total amount of unsaturated alkyl ester monomer and sulfonic acid group-containing organic monomer.

7. The preparation method of the polymer-type asphaltenes inhibitor based on nano-silica modification according to claim 1, characterized in that: The sulfonic acid group-containing organic monomer is any one of 2-acrylamido-2-methylpropanesulfonic acid, 2-methacrylamido-2-methylpropanesulfonic acid, 2-sulfoethyl acrylate or 3-sulfopropyl acrylate; The amount of the organic monomer containing sulfonic acid group added is 10% to 30% of the mass of the unsaturated alkyl ester monomer; The co-catalyst is at least one of ammonium persulfate, potassium persulfate, or tetramethylethylenediamine.

8. The preparation method of the polymer-type asphaltenes inhibitor based on nano-silica modification according to claim 1, characterized in that: The terminator is p-hydroxyanisole; The solvent for the terminating agent solution is a mixture of acetone and ethanol in a volume ratio of 1:1; The concentration of the terminator solution is 200ppm to 500ppm; The alcohol solvent is anhydrous ethanol.

9. A polymeric asphaltenes inhibitor based on nano-silica modification prepared by the method according to any one of claims 1 to 8, characterized in that: The asphaltenes inhibitor is a core-shell structured nanocomposite material with organically modified nano-silica as the core and sulfonated polyunsaturated ester as the shell. The polymer chains are chemically grafted onto the surface of the organic silica particles through covalent bonds.

10. The application of a polymer-type asphaltene inhibitor based on nano-silica modification prepared by the method of any one of claims 1 to 8 in preventing asphaltene deposition and blockage during crude oil storage in underground water-sealed caverns.

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