High-efficiency crown ether chelating scale inhibitor for oil and gas wells and preparation method thereof

Abstract

This invention relates to the field of heterocyclic compound technology, specifically to a highly efficient crown ether chelating scale remover for oil and gas wells and its preparation method. The method includes adding anhydrous potassium carbonate as an alkaline catalyst to a mixture, cooling the reaction solution to room temperature, adjusting the pH with dilute hydrochloric acid, collecting the precipitate by filtration, washing with ice water, purifying by column chromatography, collecting the target product, and vacuum drying to obtain the highly efficient crown ether chelating scale remover for oil and gas wells. This invention also involves sulfonating 4'-aminobenzo-18-crown-6 to introduce a strongly hydrophilic sulfonic acid group onto the crown ether benzene ring, thereby enhancing the crown ether cavity's resistance to Ba. 2+ / Sr 2+ Size matching and electrostatic attraction; then, multiple carboxyethyl side arms are added to form a multidentate chelate structure with crown ether cavity coordination and carboxylic acid side arm co-coordination. This structure can react with Ba under neutral conditions at 60-70℃. 2+ / Sr 2+ It forms stable complexes, significantly improving the dissolution capacity for barium sulfate and strontium sulfate scale.

Description

Technical Field

[0001] This invention relates to the field of heterocyclic compound technology, and in particular to a highly efficient crown ether chelating scale remover for oil and gas wells and its preparation method. Background Technology

[0002] During oil and gas well production, inorganic salt scaling is highly likely to occur on the wellbore, near-wellbore area, and downhole equipment surfaces due to changes in the temperature and pressure of the produced fluid and the incompatibility between formation water and injected water. Common scaling types include calcium carbonate, calcium sulfate, barium sulfate, and strontium sulfate. Among them, barium sulfate and strontium sulfate scale have extremely high chemical stability, are almost insoluble in conventional acids (such as hydrochloric acid and nitric acid), and are hard and have strong adhesion. Once formed, they are difficult to remove, seriously affecting the normal production of oil and gas wells and even leading to production shutdowns.

[0003] In recent years, crown ether compounds have been explored for the selective chelation of metal ions due to their unique cavity structure and size-selective recognition capabilities. However, conventional monocyclic crown ethers (such as 18-crown-6) have limited effectiveness against Ba. 2+ / Sr 2+ Its complexation stability is limited and its water solubility is poor, making it difficult to apply directly to water-based descaling systems.

[0004] Existing chelating agents for Ca 2+ Mg 2+ The abundant scale-forming ions lack selectivity, and in the high-hardness environment of oilfield formation water, their effective chelation capacity is largely consumed, affecting Ba. 2+ / Sr 2+ The actual removal rate is significantly reduced. Therefore, in response to the problems mentioned above, this invention proposes a high-efficiency crown ether chelating descaling agent for oil and gas wells and its preparation method. Summary of the Invention

[0005] The purpose of this invention is to provide a high-efficiency crown ether chelate scale remover for oil and gas wells and its preparation method, so as to solve the problems mentioned in the background art.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a high-efficiency crown ether chelating scale remover for oil and gas wells and its preparation method, comprising the following steps:

[0007] S1. Add anhydrous potassium carbonate to the mixture and react at 60-70℃ for 16-20h to obtain the reaction solution.

[0008] S2. Cool the reaction solution to room temperature, evaporate the solvent under reduced pressure, dilute the residue with deionized water, adjust the pH to 2-2.5 with dilute hydrochloric acid, and collect the precipitate by filtration.

[0009] S3. Wash the precipitate 2-3 times with ice water, purify it by column chromatography, collect the target product, remove the solvent by rotary evaporation, and dry it under vacuum to obtain a high-efficiency crown ether chelating scale remover for oil and gas wells.

[0010] The mixture is prepared through the following steps:

[0011] S11. Add the modified 4'-aminobenzo-18-crown-6 to anhydrous methanol and stir at room temperature until the crown ether is completely dissolved to obtain the stock solution.

[0012] S12. Dissolve acrylic acid in anhydrous methanol, add hydroquinone polymerization inhibitor and mix to obtain acrylic acid methanol solution. Under nitrogen protection, add acrylic acid methanol solution dropwise into the original solution.

[0013] S13. After the addition is complete, the temperature is raised to 40-50℃ and the reaction is continued with stirring for 8-12 hours. Methanol is removed by rotary evaporation to obtain the product. The product is then redissolved in N,N-dimethylformamide to obtain a mixed solution.

[0014] As a preferred embodiment of the present invention, the modified 4'-aminobenzo-18-crown-6 in S11 is obtained through the following steps:

[0015] S111. Dissolve 4'-aminobenzo-18-crown-6 in a mixed solution at 0-2℃ to obtain solution A. Add acetic anhydride dropwise to solution A under nitrogen protection. After the addition is complete, heat to 25-30℃ and stir for 20-24 hours to obtain a reaction solution. Add water to quench the reaction. Extract the aqueous phase with dichloromethane, wash with saturated brine, and dry the organic phase with anhydrous magnesium sulfate to obtain the crude product.

[0016] S112. Dissolve the crude product in dichloromethane, add chlorosulfonic acid dropwise at 0-2℃, and stir the reaction at 25-30℃ for 3-4 hours after the addition is complete. Neutralize the pH to 7-8 with sodium hydroxide solution, extract with dichloromethane 2-3 times, combine the organic phases, dry the organic phase with anhydrous sodium sulfate, filter, and remove the solvent by vacuum distillation to obtain the solid product.

[0017] S113. Mix the solid product with hydrochloric acid and reflux at 100-110℃ for 6-8 hours. After the reaction is complete, cool to room temperature, extract with dichloromethane to remove impurities, neutralize the aqueous phase with sodium hydroxide solution to pH 7-8, purify by column chromatography, remove solvent by rotary evaporation, and dry under vacuum to obtain modified 4'-aminobenzo-18-crown-6.

[0018] As a preferred embodiment of the present invention, the mass ratio of the mixture to anhydrous potassium carbonate in S1 is 1:(0.01-0.03).

[0019] As a preferred embodiment of the present invention, the mass ratio of modified 4'-aminobenzo-18-crown-6 to anhydrous methanol in S11 is 1:(10-20).

[0020] As a preferred embodiment of the present invention, the mass ratio of acrylic acid, anhydrous methanol and hydroquinone polymerization inhibitor in S12 is 1:(10-20):(0.005-0.01); the mass ratio of acrylic acid methanol solution to the original solution is 1:(3-5).

[0021] As a preferred embodiment of the present invention, the mass ratio of the product to N,N-dimethylformamide in S13 is 1:(10-20).

[0022] As a preferred embodiment of the present invention, the mass ratio of 4'-aminobenzo-18-crown-6 to the mixed solution in S111 is 1:(20-30), wherein the mixed solution is composed of dichloromethane and pyridine in a mass ratio of 1:(1-2); the mass ratio of acetic anhydride to solution A is 1:(30-50); and the mass ratio of the reaction solution to water is 1:(4-6).

[0023] As a preferred embodiment of the present invention, the mass ratio of crude product, dichloromethane and chlorosulfonic acid in S112 is 1:(5-15):(1-3); the dropping rate of chlorosulfonic acid is 1-2 mL / min.

[0024] As a preferred embodiment of the present invention, the mass ratio of the solid product to hydrochloric acid in S113 is 1:(10-20).

[0025] As a preferred embodiment of the present invention, a high-efficiency crown ether chelating scale remover for oil and gas wells is prepared according to the preparation method described above.

[0026] Compared with the prior art, the beneficial effects of the present invention are:

[0027] 1. This invention enhances the resistance of the crown ether cavity to Ba by sulfonating 4'-aminobenzo-18-crown-6 to introduce a strongly hydrophilic sulfonic acid group onto the crown ether benzene ring. 2+ / Sr 2+ Size matching and electrostatic attraction; then, multiple carboxyethyl side arms are added to form a multidentate chelate structure with crown ether cavity coordination and carboxylic acid side arm co-coordination. This structure can react with Ba under neutral conditions at 60-70℃. 2+ / Sr 2+ It forms a stable complex, which significantly improves the dissolution capacity of barium sulfate and strontium sulfate scale. Compared with traditional chelating agents, the present invention has a significantly improved removal effect on insoluble scale and avoids strong acid corrosion. It is especially suitable for the removal of barium and strontium scale in high-temperature deep wells.

[0028] 2. In this invention, the sulfonic acid group is a strongly hydrophilic group, which completely ionizes into -SO3 in an aqueous environment with a pH greater than 2. - This gives the molecule good water solubility; at the same time, the polycarboxyethyl side arms also partially ionize under alkaline or neutral conditions, further increasing water solubility. The descaling working solution can be prepared directly with water, avoiding the use of flammable organic solvents such as methanol and ethanol, improving on-site operation safety and reducing material costs. Attached Figure Description

[0029] Figure 1 This is a schematic diagram of the preparation process of the high-efficiency crown ether chelating scale remover for oil and gas wells in this invention;

[0030] Figure 2 This is a schematic diagram of the preparation process of the mixture in this invention;

[0031] Figure 3 This is a schematic diagram of the preparation process of modified 4'-aminobenzo-18-crown-6 in this invention. Detailed Implementation

[0032] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0033] Please see Figures 1-3 This invention provides a technical solution for a high-efficiency crown ether chelating scale remover for oil and gas wells and its preparation method:

[0034] Example 1:

[0035] A method for preparing a high-efficiency crown ether chelating scale remover for oil and gas wells includes the following steps:

[0036] I. Preparation of modified 4'-aminobenzo-18-crown-6:

[0037] S111. Take 50g of 4'-aminobenzo-18-crown-6 and dissolve it in 1000g of a mixed solution (500g of dichloromethane and 500g of pyridine in a mass ratio of 1:1) at 0℃ to obtain solution A. Under nitrogen protection, add 35g of acetic anhydride dropwise to 1050g of solution A. After the addition is complete, raise the temperature to 25℃ and stir the reaction for 20h to obtain a reaction solution. Add 400g of water to every 100g of reaction solution to quench the reaction. Extract the aqueous phase with dichloromethane and wash with saturated brine. Dry the organic phase with anhydrous magnesium sulfate, filter, and remove the solvent by vacuum distillation to obtain the crude product.

[0038] S112. Dissolve 100g of crude product in 500g of dichloromethane. Add 100g of chlorosulfonic acid dropwise at 0℃ at a rate of 1mL / min. After the addition is complete, raise the temperature to 25℃ and stir the reaction for 3h. After the reaction is complete, neutralize to pH 7 with sodium hydroxide solution, extract twice with dichloromethane, combine the organic phases, dry with anhydrous sodium sulfate, filter, and remove the solvent by vacuum distillation to obtain the solid product.

[0039] S113. Mix 100g of solid product with 1000g of 6mol / L hydrochloric acid and reflux at 100℃ for 6h. After the reaction is complete, cool to room temperature, extract with dichloromethane to remove impurities, neutralize the aqueous phase to pH 7 with sodium hydroxide solution, purify by column chromatography, remove solvent by rotary evaporation, and obtain modified 4'-aminobenzo-18-crown-6 after vacuum drying.

[0040] II. Preparation of the mixture:

[0041] S11. Take 100g of modified 4'-aminobenzo-18-crown-6, add 1000g of anhydrous methanol, stir at room temperature until completely dissolved, and obtain the stock solution.

[0042] S12. Take 50g of acrylic acid, 500g of anhydrous methanol, and 0.25g of hydroquinone polymerization inhibitor, mix them evenly to obtain an acrylic acid methanol solution, and under nitrogen protection, add 100g of the acrylic acid methanol solution to 300g of the original solution.

[0043] S13. After the addition is complete, the temperature is raised to 40°C and the reaction is stirred for 8 hours. After the reaction is complete, methanol is removed by rotary evaporation to obtain the product. 100g of the product is redissolved in 1000g of N,N-dimethylformamide to obtain a mixed solution.

[0044] III. Preparation of High-Efficiency Crown Ether Chelating Scale Removers for Oil and Gas Wells:

[0045] S1. Add 1g of anhydrous potassium carbonate to 100g of the mixture and continue the reaction at 60℃ for 16h to obtain the reaction solution.

[0046] S2. Cool the reaction solution to room temperature, evaporate the solvent under reduced pressure, dilute the residue with deionized water, adjust the pH to 2 with dilute hydrochloric acid, and collect the precipitate by filtration.

[0047] S3. Wash the precipitate twice with ice water, purify it by column chromatography, collect the target product, remove the solvent by rotary evaporation, and obtain a high-efficiency crown ether chelating scale remover for oil and gas wells after vacuum drying.

[0048] Example 2:

[0049] A method for preparing a high-efficiency crown ether chelating scale remover for oil and gas wells includes the following steps:

[0050] I. Preparation of modified 4'-aminobenzo-18-crown-6:

[0051] S111. Take 50g of 4'-aminobenzo-18-crown-6 and dissolve it in 1250g of a mixed solution (500g of dichloromethane and 750g of pyridine, mass ratio 1:1.5) at 1℃ to obtain solution A. Under nitrogen protection, add 30g of acetic anhydride dropwise to 1200g of solution A. After the addition is complete, raise the temperature to 27℃ and stir the reaction for 22h to obtain a reaction solution. Add 500g of water to every 100g of reaction solution to quench the reaction. Extract the aqueous phase with dichloromethane and wash with saturated brine. Dry the organic phase with anhydrous magnesium sulfate, filter, and remove the solvent by vacuum distillation to obtain the crude product.

[0052] S112. Dissolve 100g of crude product in 1000g of dichloromethane. Add 200g of chlorosulfonic acid dropwise at 1℃ at a rate of 1.5mL / min. After the addition is complete, raise the temperature to 28℃ and stir the reaction for 3.5h. After the reaction is complete, neutralize to pH 7.5 with sodium hydroxide solution, extract twice with dichloromethane, combine the organic phases, dry with anhydrous sodium sulfate, filter, and remove the solvent by vacuum distillation to obtain the solid product.

[0053] S113. Mix 100g of solid product with 1500g of 6mol / L hydrochloric acid and reflux at 105℃ for 7h. After the reaction is complete, cool to room temperature, extract with dichloromethane to remove impurities, neutralize the aqueous phase with sodium hydroxide solution to pH 7.5, purify by column chromatography, remove solvent by rotary evaporation, and dry under vacuum to obtain modified 4'-aminobenzo-18-crown-6.

[0054] II. Preparation of the mixture:

[0055] S11. Take 100g of modified 4'-aminobenzo-18-crown-6, add 1500g of anhydrous methanol, stir at room temperature until completely dissolved, and obtain the stock solution.

[0056] S12. Take 50g of acrylic acid, 750g of anhydrous methanol, and 0.4g of hydroquinone polymerization inhibitor, mix them evenly to obtain an acrylic acid methanol solution, and under nitrogen protection, add 100g of the acrylic acid methanol solution to 400g of the original solution.

[0057] S13. After the addition is complete, the temperature is raised to 45°C and the reaction is stirred for 10 hours. After the reaction is complete, methanol is removed by rotary evaporation to obtain the product. 100g of the product is redissolved in 1500g of N,N-dimethylformamide to obtain a mixed solution.

[0058] III. Preparation of High-Efficiency Crown Ether Chelating Scale Removers for Oil and Gas Wells:

[0059] S1. Add 2g of anhydrous potassium carbonate to 100g of the mixture and continue the reaction at 65℃ for 18h to obtain the reaction solution.

[0060] S2. Cool the reaction solution to room temperature, evaporate the solvent under reduced pressure, dilute the residue with deionized water, adjust the pH to 2.3 with dilute hydrochloric acid, and collect the precipitate by filtration.

[0061] S3. Wash the precipitate twice with ice water, purify it by column chromatography, collect the target product, remove the solvent by rotary evaporation, and obtain a high-efficiency crown ether chelating scale remover for oil and gas wells after vacuum drying.

[0062] Example 3:

[0063] A method for preparing a high-efficiency crown ether chelating scale remover for oil and gas wells includes the following steps:

[0064] I. Preparation of modified 4'-aminobenzo-18-crown-6:

[0065] S111. Take 50g of 4'-aminobenzo-18-crown-6 and dissolve it in 1500g of a mixed solution (500g of dichloromethane and 1000g of pyridine, mass ratio 1:2) at 2℃ to obtain solution A. Under nitrogen protection, add 30g of acetic anhydride dropwise to 1500g of solution A. After the addition is complete, raise the temperature to 30℃ and stir the reaction for 24h to obtain a reaction solution. Add 600g of water to every 100g of reaction solution to quench the reaction. Extract the aqueous phase with dichloromethane and wash with saturated brine. Dry the organic phase with anhydrous magnesium sulfate, filter, and remove the solvent by vacuum distillation to obtain the crude product.

[0066] S112. Dissolve 100g of crude product in 1500g of dichloromethane. Add 300g of chlorosulfonic acid dropwise at 2℃ at a rate of 2mL / min. After the addition is complete, raise the temperature to 30℃ and stir the reaction for 4h. After the reaction is complete, neutralize to pH 8 with sodium hydroxide solution, extract three times with dichloromethane, combine the organic phases, dry with anhydrous sodium sulfate, filter, and remove the solvent by vacuum distillation to obtain the solid product.

[0067] S113. Mix 100g of solid product with 2000g of 6mol / L hydrochloric acid and reflux at 110℃ for 8h. After the reaction is complete, cool to room temperature, remove impurities by extraction with dichloromethane, neutralize the aqueous phase to pH 8 with sodium hydroxide solution, purify by column chromatography, remove solvent by rotary evaporation, and obtain modified 4'-aminobenzo-18-crown-6 after vacuum drying.

[0068] II. Preparation of the mixture:

[0069] S11. Take 100g of modified 4'-aminobenzo-18-crown-6, add 2000g of anhydrous methanol, stir at room temperature until completely dissolved, and obtain the stock solution.

[0070] S12. Take 50g of acrylic acid, 1000g of anhydrous methanol, and 0.5g of hydroquinone polymerization inhibitor, mix them evenly to obtain an acrylic acid methanol solution, and under nitrogen protection, add 100g of acrylic acid methanol solution to 500g of stock solution.

[0071] S13. After the addition is complete, the temperature is raised to 50°C and the reaction is stirred for 12 hours. After the reaction is complete, methanol is removed by rotary evaporation to obtain the product. 100g of the product is redissolved in 2000g of N,N-dimethylformamide to obtain a mixed solution.

[0072] III. Preparation of High-Efficiency Crown Ether Chelating Scale Removers for Oil and Gas Wells:

[0073] S1. Add 3g of anhydrous potassium carbonate to 100g of the mixture and continue the reaction at 70℃ for 20h to obtain the reaction solution.

[0074] S2. Cool the reaction solution to room temperature, evaporate the solvent under reduced pressure, dilute the residue with deionized water, adjust the pH to 2.5 with dilute hydrochloric acid, and collect the precipitate by filtration.

[0075] S3. Wash the precipitate three times with ice water, purify it by column chromatography, collect the target product, remove the solvent by rotary evaporation, and obtain a high-efficiency crown ether chelating scale remover for oil and gas wells after vacuum drying.

[0076] Comparative Example 1:

[0077] Compared to Example 1, Comparative Example 1 replaced the modified 4'-aminobenzo-18-crown-6 with an equal mass of 4'-aminobenzo-18-crown-6, and the remaining steps were exactly the same as in Example 1.

[0078] Comparative Example 2:

[0079] Comparative Example 2, compared to Example 1, replaced the mixture with an equal mass of unmodified reaction solution (28g of 4'-aminobenzo-18-crown-6 was added, along with 373.3g of N,N-dimethylformamide and 11.2g of anhydrous potassium carbonate, and stirred at room temperature until completely dissolved to obtain the reaction solution), with the remaining steps being exactly the same as in Example 1.

[0080] The following performance tests were conducted on the descaling agent samples prepared in Examples 1-3 and Comparative Examples 1-2.

[0081] I. Water solubility test:

[0082] Weigh 1.0g of each sample and place it in a 50mL beaker. Add 20mL of deionized water and stir magnetically at 25℃ for 10min. Observe the dissolution and record the time (min) required for complete dissolution.

[0083] II. Static scale dissolution rate test (for BaSO4 scale):

[0084] Analytical purity BaSO4 powder was pressed into tablets (Φ20mm, 3mm thickness), dried at 105℃ for 2 hours, and weighed. Prepare simulated formation water (containing 5000 mg / L Na) + 500mg / L Ca 2+ 200 mg / L Mg 2+ The total mineralization was 8000 mg / L, and the pH was 7.0. 100 mL of the above water sample was taken, and each descaling agent sample (500 mg / L) was added. The mixture was stirred to dissolve the descaling agent. BaSO4 scale flakes were suspended in the solution and placed in a 90℃ constant temperature water bath for 24 hours. The scale flakes were then removed, gently rinsed with deionized water, and dried at 105℃ for 2 hours. The scale flakes were then weighed. ), Scale dissolution rate calculation:

[0085]

[0086] III. Anti-Ca 2+ / Mg 2+ Interference selectivity test:

[0087] Procedure: Same as the scale dissolution rate test above, but simulate Ca in formation water. 2+ Concentration increased to 2000 mg / L, Mg 2+ Increase the concentration to 800 mg / L (other parameters remain unchanged), measure the scale dissolution rate, compare it with the scale dissolution rate under no interference, and calculate the retention rate. Selective retention rate (%) = (scale dissolution rate under high hardness conditions / scale dissolution rate under basic conditions) × 100%.

[0088] IV. High Temperature Stability Test:

[0089] Each descaling agent sample was prepared into a 500 mg / L solution using deionized water, dispensed into pressure-resistant bottles, and aged at 120℃ and 150℃ for 24 h respectively. After cooling, the scale dissolution rate of the aged samples was determined according to the "static scale dissolution rate test" method. Thermal stability (%) = scale dissolution rate after aging / scale dissolution rate before aging × 100%. The specific test results are shown in Table 1.

[0090] Table 1: Performance Test Table of High-Efficiency Crown Ether Chelating Scale Remover for Oil and Gas Wells

[0091] Implementation Dissolution time (min) Scale dissolution rate (%) Retention rate (%) Thermal stability (%) Example 1 0.5 96.5 91.2 88.3 Example 2 0.4 97.8 93.5 90.1 Example 3 0.6 96 90.8 87.5 Comparative Example 1 3.5 68.3 52.4 45.2 Comparative Example 2 5.2 (Turbid) 54.6 48.1 38.5

[0092] As can be seen from the data in Table 1, the high-efficiency crown ether chelate scale removers for oil and gas wells prepared in Examples 1-3 are significantly better than those in Comparative Examples 1-2 in terms of water solubility, static scale dissolution rate, selectivity against ion interference, and high-temperature thermal stability. Specifically, the dissolution times of Examples 1, 2, and 3 are 0.5 min, 0.4 min, and 0.6 min, respectively, and all can be completely dissolved in deionized water within 1 min to form a clear solution. In contrast, Comparative Example 1 requires 3.5 min to dissolve, and Comparative Example 2 requires 5.2 min, and the solution is turbid. This indicates that the water solubility of the unmodified crown ether or the product without the two-step addition is significantly insufficient.

[0093] Regarding the static scale dissolution rate (for BaSO4 scale), Example 2 achieved 97.8%, slightly higher than 96.5% in Example 1 and 96.0% in Example 3. All three examples demonstrated a highly efficient scale removal capacity of over 95%. In contrast, Comparative Example 1 achieved only 68.3%, and Comparative Example 2 was even lower at 54.6%. This indicates that the sulfonic acid group and polycarboxyethyl side arm structure introduced by the present invention significantly enhance the chelation and dissolution capacity for sparingly soluble barium sulfate scale.

[0094] Anti-Ca 2+ / Mg 2+ In the interference selectivity test, Examples 1-3 simulated high-hardness formation water (Ca) 2+ 2000mg / L, Mg 2+ The scale retention rates under the condition of 800 mg / L were 91.2%, 93.5% and 90.8%, respectively, all exceeding 90%, with Example 2 showing the highest retention rate; while the retention rates of Comparative Examples 1 and 2 were only 52.4% and 48.1%, respectively, indicating that the chelation selectivity of the unmodified crown ether and single-arm product decreased significantly in the presence of a large number of competing ions.

[0095] Regarding high-temperature thermal stability, after aging at 120℃ for 24 hours, the scale retention rates of Examples 1-3 were 88.3%, 90.1%, and 87.5%, respectively, maintaining high activity and suitable for high-temperature operating environments in deep wells. In contrast, the retention rates of Comparative Examples 1 and 2 were only 45.2% and 38.5%, respectively, indicating poor thermal stability. Considering the above results, Example 2, due to its appropriate material ratio and reaction conditions, exhibits slightly better performance than Examples 1 and 3, making it a superior implementation method. The comparative examples, lacking sulfonation modification or a two-step addition step, show significantly inferior performance compared to the examples, fully verifying the key role of the technical solution of this invention.

[0096] The above are merely specific embodiments of the present invention, but the technical features of the present invention are not limited thereto. Any simple changes, equivalent substitutions or modifications made based on the present invention to solve essentially the same technical problems and achieve essentially the same technical effects are all covered within the protection scope of the present invention.

Claims

1. A method for preparing a high-efficiency crown ether chelate scale remover for oil and gas wells, characterized in that, Includes the following steps: S1. Add anhydrous potassium carbonate to the mixture and react at 60-70℃ for 16-20h to obtain the reaction solution; S2. Cool the reaction solution to room temperature, evaporate the solvent under reduced pressure, dilute the residue with deionized water, adjust the pH to 2-2.5 with dilute hydrochloric acid, and collect the precipitate by filtration. S3. Wash the precipitate with ice water 2-3 times, purify it by column chromatography, collect the target product, remove the solvent by rotary evaporation, and dry it under vacuum to obtain a high-efficiency crown ether chelating scale remover for oil and gas wells. The mixture is prepared through the following steps: S11. Add the modified 4'-aminobenzo-18-crown-6 to anhydrous methanol and stir at room temperature until the crown ether is completely dissolved to obtain the original solution; S12. Dissolve acrylic acid in anhydrous methanol, add hydroquinone polymerization inhibitor and mix to obtain acrylic acid methanol solution. Under nitrogen protection, add acrylic acid methanol solution dropwise into the original solution. S13. After the addition is complete, heat to 40-50℃ and continue stirring for 8-12 hours. Remove methanol by rotary evaporation to obtain the product. Redissolve the product in N,N-dimethylformamide to obtain a mixture.

2. The preparation method of the high-efficiency crown ether chelating scale remover for oil and gas wells according to claim 1, characterized in that: The modified 4'-aminobenzo-18-crown-6 in S11 is obtained through the following steps: S111. Dissolve 4'-aminobenzo-18-crown-6 in a mixed solution at 0-2℃ to obtain solution A. Add acetic anhydride dropwise to solution A under nitrogen protection. After the addition is complete, heat to 25-30℃ and stir for 20-24 hours to obtain a reaction solution. Add water to quench the reaction. Extract the aqueous phase with dichloromethane, wash with saturated brine, and dry the organic phase with anhydrous magnesium sulfate to obtain the crude product. S112. Dissolve the crude product in dichloromethane, add chlorosulfonic acid dropwise at 0-2℃, and stir the reaction at 25-30℃ for 3-4 hours after the addition is complete. Neutralize the pH to 7-8 with sodium hydroxide solution, extract with dichloromethane 2-3 times, combine the organic phases, dry the organic phase with anhydrous sodium sulfate, filter, remove the solvent by vacuum distillation, and obtain the solid product. S113. Mix the solid product with hydrochloric acid and reflux at 100-110℃ for 6-8 hours. After the reaction is complete, cool to room temperature, extract with dichloromethane to remove impurities, neutralize the aqueous phase with sodium hydroxide solution to pH 7-8, purify by column chromatography, remove solvent by rotary evaporation, and dry under vacuum to obtain modified 4'-aminobenzo-18-crown-6.

3. The preparation method of the high-efficiency crown ether chelating scale remover for oil and gas wells according to claim 1, characterized in that: The mass ratio of the mixture to anhydrous potassium carbonate in S1 is 1:(0.01-0.03).

4. The preparation method of the high-efficiency crown ether chelating scale remover for oil and gas wells according to claim 1, characterized in that: The mass ratio of modified 4'-aminobenzo-18-crown-6 to anhydrous methanol in S11 is 1:(10-20).

5. The preparation method of the high-efficiency crown ether chelating scale remover for oil and gas wells according to claim 1, characterized in that: The mass ratio of acrylic acid, anhydrous methanol, and hydroquinone polymerization inhibitor in S12 is 1:(10-20):(0.005-0.01). The mass ratio of the acrylic acid methanol solution to the original solution is 1:(3-5).

6. The preparation method of the high-efficiency crown ether chelating scale remover for oil and gas wells according to claim 1, characterized in that: The mass ratio of the product to N,N-dimethylformamide in S13 is 1:(10-20).

7. The preparation method of the high-efficiency crown ether chelating scale remover for oil and gas wells according to claim 2, characterized in that: The mass ratio of 4'-aminobenzo-18-crown-6 to the mixed solution in S111 is 1:(20-30), wherein the mixed solution is composed of dichloromethane and pyridine in a mass ratio of 1:(1-2); The mass ratio of acetic anhydride to solution A is 1:(30-50). The mass ratio of the reaction solution to water is 1:(4-6).

8. The preparation method of the high-efficiency crown ether chelate scale remover for oil and gas wells according to claim 2, characterized in that: The mass ratio of crude product, dichloromethane and chlorosulfonic acid in S112 is 1:(5-15):(1-3). The dropping rate of the chlorosulfonic acid is 1-2 mL / min.

9. The preparation method of the high-efficiency crown ether chelating scale remover for oil and gas wells according to claim 2, characterized in that: The mass ratio of the solid product to hydrochloric acid in S113 is 1:(10-20).

10. A high-efficiency crown ether chelate scale remover for oil and gas wells, characterized in that, Prepared by the preparation method according to any one of claims 1-9.

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