High-temperature acidizing corrosion inhibitor as well as preparation method and application thereof

Abstract

The invention discloses a high-temperature acidizing corrosion inhibitor as well as a preparation method and application thereof, and relates to the technical field of corrosion prevention and inhibition. The high-temperature acidizing corrosion inhibitor disclosed by the invention is prepared by taking a dicarboxyl pyridine Schiff base intermediate and tris (2-aminothiophene) isocyanurate as novel functional monomers through melt polymerization reaction. The high-temperature acidizing corrosion inhibitor prepared by the invention is a macromolecular hyperbranched polyamide polymer, contains a high-temperature-resistant isocyanurate heterocyclic structure, is good in heat resistance and high in structural stability, is not easy to decompose at high temperature and under an acid medium, can keep good corrosion inhibition performance, and has a wide application prospect in the fields of oil and gas well exploitation and the like.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of corrosion and inhibition technology, in particular to a high-temperature acidification corrosion inhibitor and a preparation method and application thereof. BACKGROUND

[0002] In the process of oil and gas exploitation, due to the blockage in the pipeline during exploitation and transportation, it is usually necessary to inject acid liquid into the formation to restore the permeability of the formation, so as to achieve the effect of increasing the production of oil and gas wells. However, the injection of acid liquid will cause corrosion of the wellbore, pipeline and other equipment, and the addition of corrosion inhibitor to the acid liquid can overcome the corrosion of the wellbore and other equipment. During the exploitation of oil and gas wells, as the depth of the oil and gas well increases, the temperature of the reservoir also increases, and the corrosion of the acid liquid to the wellbore, pipeline and other equipment will be very serious at high temperature, and the corrosion inhibitor may have the problem of thermal decomposition at high temperature, therefore, higher requirements are put forward for the corrosion inhibition performance and high temperature performance of the acidification corrosion inhibitor. For example, the patent with the authorization announcement number CN110283581B discloses an acidification corrosion inhibitor, which is compounded by aldehyde ketone amine condensate, synergist, dispersant and the like, and an acidification corrosion inhibitor suitable for high temperature above 160 DEG C is obtained. Although it can reduce the corrosion risk of the downhole pipe string in the process of high-temperature carbonated rock acidification reconstruction in deep and ultra-deep layers, the acidification corrosion inhibitor still has the problems of fast corrosion rate and poor corrosion inhibition performance. SUMMARY

[0003] The main purpose of the present application is to provide a high-temperature acidification corrosion inhibitor and a preparation method and application thereof, so as to solve the problems of fast corrosion rate and poor corrosion inhibition performance of the existing acidification corrosion inhibitor.

[0004] In order to achieve the above-mentioned purpose, the present application provides a preparation method of a high-temperature acidification corrosion inhibitor, which is prepared by melt polymerization reaction of tris(2-aminothiophene) isocyanurate and a dicarboxypyridine Schiff base intermediate: the structural formula of the tris(2-aminothiophene) isocyanurate is: The structural formula of the dicarboxypyridine Schiff base intermediate is:

[0005] In the foregoing method, the preparation reaction formula of the high-temperature acidification corrosion inhibitor is as follows:

[0006]

[0007] The present application is a new type of functional monomer with bishydroxy pyridine Schiff base intermediate and tris (2-aminothiophene) isocyanurate as a new type of functional monomer, which is prepared by melt polymerization reaction, and then a high temperature acidification corrosion inhibitor is prepared. The high temperature acidification corrosion inhibitor prepared by the above method has a three-dimensional dendritic structure of hyperbranched polyamide, which contains a large number of amide bonds, pyridine Schiff base and thiophene structural units, which can form coordination bond and complexation with iron atoms on the surface of steel, and then a macromolecular protective film of hyperbranched polymer can be formed on the surface of steel, which has high adsorption firmness, can effectively inhibit the contact between steel and corrosive medium, reduce the corrosion rate and has excellent corrosion inhibition performance.

[0008] Meanwhile, the high temperature acidification corrosion inhibitor of the present application contains cyanuric acid ester heterocyclic structure with high temperature resistance, good heat resistance, high structural stability and is not easy to decompose under high temperature and acidic medium, which can further improve the corrosion inhibition performance of the high temperature acidification corrosion inhibitor. In summary, the high temperature acidification corrosion inhibitor of the present application has high temperature resistance effect, is suitable for high concentration hydrochloric acid and other acidification media, and can be better applied in the field of oil and gas well exploitation.

[0009] Further, the molar ratio of the tris (2-aminothiophene) isocyanurate to the bishydroxy pyridine Schiff base intermediate is 1:1.5-2.

[0010] Further, the temperature of the melt polymerization reaction is 200-230℃, and the time is 1-3h.

[0011] Further, the preparation method of the high temperature acidification corrosion inhibitor comprises the following steps: S1, mixing N,N-dimethylformamide, 2-nitro-5-bromothiophene and cyanuric acid, stirring and dissolving, then adding cuprous iodide and cesium carbonate dropwise, passing nitrogen, reacting at a temperature of 120-140℃ for 36-60h, pouring the reacted solution into methanol for precipitation, filtering, washing the filtered precipitate, then adding to an iron powder-containing glacial acetic acid solution, stirring uniformly, reacting at a temperature of 50-60℃ for 4-7h, and then sequentially performing extraction separation, organic phase drying and concentration to obtain the tris (2-aminothiophene) isocyanurate;

[0012] S2, adding the tris (2-aminothiophene) isocyanurate and the bishydroxy pyridine Schiff base intermediate into a reaction bottle, passing nitrogen, performing the melt polymerization reaction, and then sequentially performing cooling, washing and drying of the reacted product to obtain the high temperature acidification corrosion inhibitor.

[0013] In the foregoing method, the preparation reaction formula of the tris (2-aminothiophene) isocyanurate is as follows:

[0014]

[0015] Further, in the S1, the molar ratio of 2-nitro-5-bromothiophene, cyanuric acid, cuprous iodide and cesium carbonate is (3.6-4.5):1:(0.01-0.018):(4-6).

[0016] Further, in the S1, the molar concentration of iron powder in the glacial acetic acid solution is 3-4 mol / L.

[0017] Further, in the S1, the precipitate of the solution is washed with water and diethyl ether in sequence.

[0018] Further, the preparation method of the double carboxyl pyridine Schiff base intermediate is as follows: the solvent, glutaraldehyde and 6-aminonicotinic acid are mixed and stirred, and then the reaction is carried out, and then the solvent is concentrated and recrystallized to obtain the double carboxyl pyridine Schiff base intermediate.

[0019] In the foregoing method, the preparation reaction formula of the double carboxyl pyridine Schiff base intermediate is as follows:

[0020]

[0021] Further, the molar ratio of the glutaraldehyde and the 6-aminonicotinic acid is 1:1.8-2.8.

[0022] Further, the reaction is refluxed at a temperature of 60-80℃ for 3-8h.

[0023] Further, the solvent is selected from one or more of ethanol, isopropanol or 1,4-dioxane.

[0024] Another aspect of the present application provides a high-temperature acidification corrosion inhibitor prepared by the foregoing preparation method of the high-temperature acidification corrosion inhibitor.

[0025] Another aspect of the present application also provides the use of the foregoing high-temperature acidification corrosion inhibitor in a high-temperature oil well acidification fluid.

[0026] Compared with the prior art, the application has the following beneficial effects: the high-temperature acidification corrosion inhibitor is prepared by using bishydroxypyridine Schiff base intermediate and tris(2-aminothiophene) isocyanurate as new functional monomers through melt polymerization reaction. The high-temperature acidification corrosion inhibitor has a three-dimensional dendritic structure of hyperbranched polyamide, contains a large number of amide bonds, pyridine Schiff base and thiophene structural units, can form coordination bonds and complexation with iron atoms on the surface of steel, and further forms a macromolecular protective film of hyperbranched polymer on the surface of steel. The macromolecular protective film has high adsorption firmness, can effectively inhibit the contact between steel and corrosive medium, reduces the corrosion rate and thus has excellent corrosion inhibition performance. Meanwhile, the high-temperature acidification corrosion inhibitor contains cyanurate heterocyclic structure with high-temperature resistance, has good heat resistance, high structural stability and is not easy to decompose under high temperature and acidic medium, and can further improve the corrosion inhibition effect of the corrosion inhibitor.

[0027] In conclusion, the high-temperature acidification corrosion inhibitor prepared by the application is a macromolecular hyperbranched polyamide polymer, contains cyanurate heterocyclic structure with high-temperature resistance, has good heat resistance, high structural stability and is not easy to decompose under high temperature and acidic medium, can maintain good corrosion inhibition performance, and has wide application prospects in the field of oil and gas well exploitation. DETAILED DESCRIPTION

[0028] It should be noted that the embodiments in the application and the features in the embodiments can be combined with each other without conflict. The application will be described in detail below with reference to the embodiments.

[0029] Embodiment 1

[0030] The preparation method of the bishydroxypyridine Schiff base intermediate is as follows: 100 mL of isopropyl alcohol, 20 mmol of glutaraldehyde and 56 mmol of 6-aminonicotinic acid are added to a reaction bottle, the reaction is stirred and refluxed at a temperature of 80℃ for 6 h, the solvent is concentrated, and the product after concentration is recrystallized in ethyl acetate to obtain the bishydroxypyridine Schiff base intermediate.

[0031] The preparation method of the tris(2-aminothiophene) isocyanurate is as follows: 150 mL of N,N-dimethylformamide, 60 mmol of 2-nitro-5-bromothiophene and 15 mmol of cyanuric acid are added to a reaction bottle, stirred and dissolved, then 0.21 mmol of cuprous iodide and 70 mmol of cesium carbonate are added dropwise, nitrogen is introduced, and the reaction is carried out at a temperature of 130℃ for 36 h. The solution after reaction is poured into methanol for precipitation, filtration, and then the precipitate is washed with water and diethyl ether in sequence. Then the product is added to a 60 mL ice acetic acid solution containing iron powder, the molar concentration of iron powder in the ice acetic acid solution is controlled to be 3 mol / L, stirred uniformly, and the reaction is carried out at a temperature of 60℃ for 4 h. Saturated sodium bicarbonate solution and ethyl acetate are added for extraction and separation, the organic phase is dried and concentrated to obtain the tris(2-aminothiophene) isocyanurate.

[0032] The preparation process of the high-temperature acidification corrosion inhibitor is as follows: 20 mmol of tris(2-aminothiophene) isocyanurate and 30 mmol of the dicarboxy pyridine Schiff base intermediate are added to a reaction bottle, nitrogen is introduced, and a melt polymerization reaction is performed at a temperature of 200°C for 3 h; the product after the reaction is sequentially washed with ethanol and dichloromethane after being cooled, and dried to obtain the hyperbranched polyamide type high-temperature acidification corrosion inhibitor.

[0033] Example 2

[0034] The preparation method of the dicarboxy pyridine Schiff base intermediate is as follows: 80 mL of ethanol, 20 mmol of glutaraldehyde, and 45 mmol of 6-aminonicotinic acid are added to a reaction bottle, and a reflux reaction is performed at a temperature of 70°C for 5 h while stirring; the solvent is concentrated, and the product after the concentration is recrystallized in ethyl acetate to obtain the dicarboxy pyridine Schiff base intermediate.

[0035] The preparation method of tris(2-aminothiophene) isocyanurate is as follows: 200 mL of N,N-dimethylformamide, 67.5 mmol of 2-nitro-5-bromothiophene, and 15 mmol of cyanuric acid are added to a reaction bottle, and then 0.27 mmol of cuprous iodide and 90 mmol of cesium carbonate are added dropwise while stirring and dissolving; nitrogen is introduced, and a reaction is performed at a temperature of 130°C for 48 h; the solution after the reaction is poured into methanol for precipitation, and then filtered; the precipitate is sequentially washed with water and diethyl ether; then the product is added to a 40 mL ice acetic acid solution containing iron powder, the molar concentration of the iron powder in the solution is controlled to be 4 mol / L, and stirring is uniformly performed; a reaction is performed at a temperature of 50°C for 7 h; saturated sodium bicarbonate solution and ethyl acetate are added for extraction and separation; the organic phase is dried and concentrated to obtain tris(2-aminothiophene) isocyanurate.

[0036] The preparation process of the high-temperature acidification corrosion inhibitor is as follows: 20 mmol of tris(2-aminothiophene) isocyanurate and 40 mmol of the dicarboxy pyridine Schiff base intermediate are added to a reaction bottle, nitrogen is introduced, and a melt polymerization reaction is performed at a temperature of 200°C for 2 h; the product after the reaction is sequentially washed with ethanol and dichloromethane after being cooled, and dried to obtain the hyperbranched polyamide type high-temperature acidification corrosion inhibitor.

[0037] Example 3

[0038] The preparation method of the dicarboxy pyridine Schiff base intermediate is as follows: 100 mL of ethanol, 20 mmol of glutaraldehyde, and 56 mmol of 6-aminonicotinic acid are added to a reaction bottle, and a reflux reaction is performed at a temperature of 70°C for 5 h while stirring; the solvent is concentrated, and the product after the concentration is recrystallized in ethyl acetate to obtain the dicarboxy pyridine Schiff base intermediate.

[0039] The preparation method of tris(2-aminothiophene) isocyanurate is as follows: 100 mL of N,N-dimethylformamide, 54 mmol of 2-nitro-5-bromothiophene, 15 mmol of cyanuric acid are added to a reaction bottle, stirred and dissolved, then 0.15 mmol of cuprous iodide and 60 mmol of cesium carbonate are added dropwise, nitrogen is introduced, and the reaction is carried out at a temperature of 120°C for 60h. The solution after the reaction is poured into methanol for precipitation, filtration, and the precipitate is washed with water and diethyl ether in turn. Then the product is added to a 50 mL ice acetic acid solution containing iron powder, the molar concentration of iron powder in the solution is controlled to be 3.5 mol / L, stirred uniformly, and reacted at a temperature of 50°C for 6h. Saturated sodium bicarbonate solution and ethyl acetate are added for extraction and separation, the organic phase is dried, concentrated, and tris(2-aminothiophene) isocyanurate is obtained.

[0040] The preparation process of the high-temperature acidification corrosion inhibitor is as follows: 20 mmol of tris(2-aminothiophene) isocyanurate and 40 mmol of the double-carboxyl pyridine Schiff base intermediate are added to a reaction bottle, nitrogen is introduced, and the melt polymerization reaction is carried out at a temperature of 220°C for 2h. The product after the reaction is cooled and washed with ethanol and dichloromethane in turn, and dried to obtain a hyperbranched polyamide type high-temperature acidification corrosion inhibitor.

[0041] Example 4

[0042] The preparation method of the double-carboxyl pyridine Schiff base intermediate is as follows: 60 mL of 1,4-dioxane, 20 mmol of glutaraldehyde, and 36 mmol of 6-aminonicotinic acid are added to a reaction bottle, stirred and refluxed at a temperature of 60°C for 3h. The solvent is concentrated, and the product is recrystallized in ethyl acetate to obtain the double-carboxyl pyridine Schiff base intermediate.

[0043] The preparation method of tris(2-aminothiophene) isocyanurate is as follows: 150 mL of N,N-dimethylformamide, 60 mmol of 2-nitro-5-bromothiophene, and 15 mmol of cyanuric acid are added to a reaction bottle, stirred and dissolved, then 0.27 mmol of cuprous iodide and 70 mmol of cesium carbonate are added dropwise, nitrogen is introduced, and the reaction is carried out at a temperature of 120°C for 60h. The solution after the reaction is poured into methanol for precipitation, filtration, and the precipitate is washed with water and diethyl ether in turn. Then the product is added to a 40 mL ice acetic acid solution containing iron powder, the molar concentration of iron powder in the solution is controlled to be 4 mol / L, stirred uniformly, and reacted at a temperature of 60°C for 4h. Saturated sodium bicarbonate solution and ethyl acetate are added for extraction and separation, the organic phase is dried, concentrated, and tris(2-aminothiophene) isocyanurate is obtained.

[0044] The preparation process of the high-temperature acidizing corrosion inhibitor: 20 mmol of tris(2-aminothiophene) isocyanurate, 35 mmol of dicarboxypyridine Schiff base intermediate are added to the reaction bottle, nitrogen is introduced, and the melt polymerization reaction is carried out at 230°C for 1h, and then the product after reaction is washed with ethanol and dichloromethane in turn, and dried to obtain a hyperbranched polyamide type high-temperature acidizing corrosion inhibitor.

[0045] Comparative Example 1

[0046] The dicarboxypyridine Schiff base intermediate is directly used as the corrosion inhibitor, and the preparation process is as shown in Example 1.

[0047] Comparative Example 2

[0048] The tris(2-aminothiophene) isocyanurate is directly used as the corrosion inhibitor, and the preparation process is as shown in Example 1.

[0049] The corrosion inhibition performance of the corrosion inhibitors of Examples 1-4 and Comparative Examples 1-2 is tested according to the method of SY / T 5405-2019.

[0050] The corrosion rate test process of the corrosion inhibitor with different mass fractions: the test material is N80 steel with a clean surface, the corrosion medium is a 5% hydrochloric acid solution, and the mass fraction of the corrosion inhibitor is 0.5-4%. The N80 steel single piece is hung and immersed in the hydrochloric acid solution, the temperature is controlled at 90°C, and the time is 4h, the mass difference (△m) of the N80 steel before and after corrosion is calculated, and the corrosion rate V; V=(△m) / (A·t), A is the surface area of the N80 steel, and t is the corrosion time.

[0051] Table 1 is a corrosion rate test table of the corrosion inhibitor with different mass fractions.

[0052] Table 1

[0053]

[0054] The high-temperature acidizing corrosion inhibitor prepared in Examples 1-4 has the lowest corrosion rate of only 10.7g / m 2 ·h and the best corrosion inhibition efficiency when the mass fraction of the corrosion inhibitor is 3-4%. This is because the high-temperature acidizing corrosion inhibitor has a three-dimensional dendritic structure of hyperbranched polyamide, contains a large number of amide bonds, pyridine Schiff base and thiophene structural units, can form coordination bonds and complexation with iron atoms on the steel surface, form a macromolecular protective film of hyperbranched polymer on the steel surface, and has high adsorption firmness, inhibits the contact between the steel and the corrosion medium, reduces the corrosion rate and thus has excellent corrosion inhibition performance.

[0055] Comparative Example 1 uses a dicarboxypyridine Schiff base intermediate as the corrosion inhibitor; Comparative Example 2 uses tris(2-aminothiophene) isocyanurate as the corrosion inhibitor; both have a high corrosion rate and poor corrosion inhibition performance. This is because the dicarboxypyridine Schiff base intermediate of Comparative Example 1 does not contain an amide bond or a thiophene structure, and the tris(2-aminothiophene) isocyanurate of Comparative Example 2 does not contain an amide bond or a pyridine Schiff base structure, and the coordination with iron atoms on the steel surface is low, and both are small molecules and cannot form a large molecule protective film on the steel surface, so the corrosion inhibition performance is poor.

[0056] Table 2 is a corrosion rate test table for different concentrations of hydrochloric acid.

[0057] Table 2

[0058]

[0059]

[0060] When the mass fraction of the corrosion inhibitor is 3%, in a 10% low concentration hydrochloric acid medium, the high temperature acidizing corrosion inhibitor prepared in Example 2 has the lowest corrosion rate of only 13.9 g / m 2 ·h; in a 20% high concentration hydrochloric acid medium, the high temperature acidizing corrosion inhibitor prepared in Example 1 has the lowest corrosion rate of only 31.8 g / m 2 ·h. Much lower than Comparative Examples 1 and 2.

[0061] The corrosion rate test process of the corrosion inhibitor at different temperatures: the test material is N80 steel with a clean surface, the corrosion medium is a 5% concentration hydrochloric acid solution, and the mass fraction of the corrosion inhibitor is 3%. The N80 steel single piece is hung and immersed in the hydrochloric acid solution, and the temperature is controlled at 90-180°C for 4h.

[0062] Table 3 is a corrosion rate test table for the corrosion inhibitor at different temperatures.

[0063] Table 3

[0064]

[0065] At a higher temperature of 120°C, the high temperature acidizing corrosion inhibitor prepared in Example 2 has the lowest corrosion rate of only 15.8 g / m 2 ·h; at a high temperature of 180°C, the high temperature acidizing corrosion inhibitor prepared in Example 4 has the lowest corrosion rate of only 26.5 g / m 2• h, has excellent high-temperature corrosion inhibition performance. This is because the high-temperature acidizing corrosion inhibitor is a macromolecular hyperbranched polyamide, and also contains a high-temperature-resistant isocyanurate heterocyclic structure, has good heat resistance, high structural stability, and is not easy to decompose under high temperature and acidic medium, and can maintain good corrosion inhibition performance. Comparative Example 1 uses a dicarboxypyridine Schiff base intermediate as a corrosion inhibitor; Comparative Example 2 uses tris(2-aminothiophene) isocyanurate as a corrosion inhibitor; both are small molecules, have poor heat resistance, and may undergo structural decomposition under high temperature and acidic medium, resulting in a sharp increase in corrosion rate and a serious decrease in corrosion inhibition performance.

[0066] Obviously, the above embodiments of the present application are only examples for clearly illustrating the present application, and are not intended to limit the embodiments of the present application. For those skilled in the art, other different forms of changes or variations can be made on the basis of the above description, and it is impossible to enumerate all the embodiments here. Any obvious changes or variations derived from the technical solutions of the present application are still within the protection scope of the present application.

Claims

1. A method for preparing a high-temperature acidification corrosion inhibitor, characterized in that: The high-temperature acidification corrosion inhibitor is prepared by melt polymerization of tris(2-aminothiophene) isocyanurate and dicarboxylpyridine Schiff base intermediate; The structural formula of the tris(2-aminothiophene)isocyanurate is: The structural formula of the dicarboxylpyridine Schiff base intermediate is:

2. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 1, wherein: The molar ratio of the tris(2-aminothiophene)isocyanurate to the dicarboxylpyridine Schiff base intermediate is 1:1.5-2.

3. The method for preparing the high temperature acidification corrosion inhibitor according to claim 1 or 2, characterized in that: The temperature of the melt polymerization reaction is 200-230° C., and the time is 1-3 hours.

4. The method for preparing a high-temperature acidizing corrosion inhibitor according to any one of claims 1 to 3, characterized in that: The following steps are involved: S1, N,N-dimethylformamide, 2-nitro-5-bromothiophene, and cyanuric acid are mixed and stirred to dissolve, and then cuprous iodide and cesium carbonate are added dropwise, nitrogen is introduced, and the reaction is carried out at a temperature of 120-140° C. for 36-60 hours. The solution after the reaction is poured into methanol for precipitation and filtered. The filtered precipitate is washed and then added to a glacial acetic acid solution containing iron powder and stirred uniformly. The reaction is carried out at a temperature of 50-60° C. for 4-7 hours, and then extraction and separation, the organic phase is dried, and concentrated to obtain the tris(2-aminothiophene)isocyanurate; S2, adding the tris(2-aminothiophene)isocyanurate and the dicarboxylpyridine Schiff base intermediate into a reaction flask, introducing nitrogen, and performing the melt polymerization reaction, and then cooling, washing, and drying the reaction product in sequence to obtain the high-temperature acidification corrosion inhibitor.

5. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 4, wherein: In the S1, the molar ratio of 2-nitro-5-bromothiophene, cyanuric acid, cuprous iodide and cesium carbonate is (3.6-4.5):1:(0.01-0.018):(4-6).

6. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 4, characterized in that: In S1, the molar concentration of the iron powder in the glacial acetic acid solution is 3-4 mol / L.

7. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 4, wherein: The preparation method of the dicarboxylpyridine Schiff base intermediate is as follows: a solvent, glutaraldehyde and 6-aminonicotinic acid are mixed and stirred to react, and then the solvent is concentrated and recrystallized to obtain the dicarboxylpyridine Schiff base intermediate.

8. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 7, characterized in that: The molar ratio of the glutaraldehyde to the 6-aminonicotinic acid is 1:1.8-2.8; Preferably, the reaction is refluxed at a temperature of 60-80° C. for 3-8 hours; Preferably, the solvent is selected from one or more of ethanol, isopropanol or 1,4-dioxane.

9. A high temperature acidification corrosion inhibitor, characterized in that: The high-temperature acidizing corrosion inhibitor is prepared by the preparation method of any one of claims 1 to 8.

10. Use of the high-temperature acidizing corrosion inhibitor according to claim 9 in high-temperature oil well acidizing fluid.

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