Multipurpose high-temperature acidizing corrosion inhibitor for oil field and preparation method thereof

Abstract

The invention relates to the technical field of corrosion inhibitors for oil wells, in particular to a multipurpose high-temperature acidizing corrosion inhibitor for an oil field and a preparation method thereof, and the multipurpose high-temperature acidizing corrosion inhibitor for the oil field is obtained according to the following method: adding a required amount of N 'N-dimethylformamide, butynediol and an emulsifier into self-made bis-schiff base quaternary ammonium salt, fully stirring, then adding benzotriazole, and stirring to obtain the multipurpose high-temperature acidizing corrosion inhibitor. According to the invention, the self-made bis-Schiff base quaternary ammonium salt can form a compact and firm adsorption film on a metal matrix, so that contact between an acid solution and metal is reduced, and effective protection is realized; the raw materials are also compounded with other small molecular compounds of N 'N-dimethylformamide, butynediol emulsifier and benzotriazole, so that the multipurpose high-temperature acidizing corrosion inhibitor for the oil field has the characteristics of strong adaptability, good temperature resistance and good corrosion inhibition effect aiming at different acid liquor types.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of corrosion inhibitors for oil wells, and is a multipurpose high-temperature acidizing corrosion inhibitor for oil fields and a preparation method thereof. BACKGROUND

[0002] With the increasing demand for oil and gas resources in China, oil and gas fields have also begun large-scale development, constantly increasing oil and gas production. Acidizing is to inject hydrochloric acid, mud acid or other types of acid into the formation, expand the permeation channel of the oil and gas layer rock through the dissolution of the rock, restore or increase the permeability of the oil and gas layer, so as to achieve the purpose of increasing the yield of the oil and gas field. However, various types of acid used in the acidizing process have serious corrosion on the oil well pipe column and related equipment, especially a large amount of pitting corrosion on the surface of steel, which greatly shortens the service life of the oil well pipe column and equipment. Therefore, during the acidizing construction of the oil and gas well, an effective acidizing corrosion inhibitor must be added to reduce the corrosion of the acid on the pipe column and improve the service life of the oil and gas well.

[0003] At present, the number of ultra-deep wells and ultra-high pressure gas wells encountered during the development of oil and gas fields is increasing, and the state attaches more and more importance to environmental protection, which puts higher and higher requirements on the performance of the acidizing corrosion inhibitor. Not only should the acidizing corrosion inhibitor have good high-temperature resistance, but also should not cause great harm to the environment. However, the existing acidizing corrosion inhibitors have poor effects at high temperatures, and the pitting corrosion on the surface of steel is serious. In addition, due to different geological conditions, different types of acid are used in different regions, which makes the existing acidizing corrosion inhibitors unable to meet the requirements of high-temperature acidizing of different types of acid systems. The high-temperature acidizing corrosion inhibitors used at home and abroad are generally composed of multiple components, and the selected propargyl alcohol, metal antimony and other compounds for mutual compounding of the high-temperature acidizing corrosion inhibitors cause serious environmental pollution. Therefore, the existing high-temperature acidizing corrosion inhibitors have poor temperature resistance and low applicability to different acid systems. SUMMARY

[0004] The present application provides a multipurpose high-temperature acidizing corrosion inhibitor for oil fields and a preparation method thereof, which overcomes the shortcomings of the prior art and effectively solves the problems of poor temperature resistance and low applicability to different acid systems of the existing high-temperature acidizing corrosion inhibitors.

[0005] One of the technical solutions of the present application is realized by the following measures: a multipurpose high-temperature acidizing corrosion inhibitor for oil fields, the raw materials include 25-30 parts of bis-Schiff base quaternary ammonium salt, 55-60 parts of N’N-dimethylformamide, 4-6 parts of butyne diol, 5-10 parts of emulsifier and 1-3 parts of benzotriazole, by weight.

[0006] The following is a further optimization or / and improvement of one of the above-mentioned technical solutions of the present application: The emulsifier is one of Tween 20 and emulsifier OP-10.

[0007] The above-mentioned double Schiff base quaternary ammonium salt is obtained by using salicylaldehyde, 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl] and 3-chloro-2-hydroxypropanesulfonic acid sodium in a mass ratio of (2.2 to 2.4):1:2 as raw materials according to the following method: In the first step, the required amount of salicylaldehyde and 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl] are added to the solvent toluene and stirred to obtain a mixture, then 3-chloro-2-hydroxypropanesulfonic acid sodium is added to the mixture and stirred to obtain a Schiff base. In the second step, the required amount of 3-chloro-2-hydroxypropanesulfonic acid sodium is added to the Schiff base and stirred to obtain a double Schiff base quaternary ammonium salt.

[0008] In the above-mentioned first step, 60g to 70g of solvent toluene is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl], and 1ml to 2ml of acetic acid is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl].

[0009] In the above-mentioned first step, the reaction temperature is 100°C to 120°C, and the reaction time is 7h to 9h.

[0010] In the above-mentioned second step, the reaction temperature is 80°C to 90°C, and the reaction time is 10h to 14h.

[0011] The above-mentioned oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained by adding the required amount of N,N-dimethylformamide, butyne diol and emulsifier to the required amount of double Schiff base quaternary ammonium salt, stirring thoroughly to obtain an intermediate mixture, and then adding the required amount of benzotriazole to the intermediate mixture and stirring to obtain the oilfield multipurpose high-temperature acidizing corrosion inhibitor.

[0012] The second technical solution of the present application is realized by the following measures: a preparation method of an oilfield multipurpose high-temperature acidizing corrosion inhibitor, which is prepared by adding the required amount of N,N-dimethylformamide, butyne diol and emulsifier to the required amount of double Schiff base quaternary ammonium salt, stirring thoroughly to obtain an intermediate mixture, and then adding the required amount of benzotriazole to the intermediate mixture and stirring to obtain the oilfield multipurpose high-temperature acidizing corrosion inhibitor.

[0013] The application can form a dense and firm adsorption film on a metal base through the self-made double Schiff base quaternary ammonium salt, reduces the contact of acid liquid with the metal to achieve effective protection, and meanwhile, the raw materials are compounded with other small molecular compounds of N'N-dimethylformamide, butyne diol emulsifier and benzotriazole, so that the oilfield multipurpose high-temperature acidification corrosion inhibitor has the characteristics of strong adaptability, good temperature resistance and good corrosion inhibition effect for different acid liquid types. DETAILED DESCRIPTION

[0014] The application is not limited by the following examples, and the specific implementation can be determined according to the technical scheme and actual situation of the application. The various chemical reagents and chemical products mentioned in the application are common chemical reagents and chemical products known in the prior art unless otherwise specified; the percentages in the application are mass percentages unless otherwise specified; the solution in the application is an aqueous solution with water as the solvent unless otherwise specified, for example, a hydrochloric acid solution is an aqueous hydrochloric acid solution; the normal temperature and room temperature in the application generally refer to a temperature of 15-25 DEG C, and are generally defined as 25 DEG C.

[0015] The application will be further described below in combination with examples: Example 1: The oilfield multipurpose high-temperature acidification corrosion inhibitor includes 25-30 parts of double Schiff base quaternary ammonium salt, 55-60 parts of N'N-dimethylformamide, 4-6 parts of butyne diol, 5-10 parts of emulsifier and 1-3 parts of water-soluble benzotriazole by weight.

[0016] Example 2: As an optimization of the above examples, the emulsifier is one of Tween 20 and emulsifier OP-10.

[0017] Example 3: As an optimization of the above examples, the double Schiff base quaternary ammonium salt is obtained by the following method: First step, a required amount of salicylaldehyde and 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl] is added to a solvent toluene and stirred to obtain a mixed solution, then acetic acid is added to the mixed solution, mixed and reacted to obtain a Schiff base; Second step, a required amount of 3-chloro-2-hydroxypropanesulfonic acid sodium is added to the Schiff base, mixed and reacted to obtain a double Schiff base quaternary ammonium salt.

[0018] Example 4: As an optimization of the above examples, in the first step, 60-70 g of solvent toluene is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl], and 1-2 ml of acetic acid is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl].

[0019] Example 5: As an optimization of the above-mentioned examples, in the first step, the reaction temperature is 100-120°C, and the reaction time is 7-9h.

[0020] Example 6: As an optimization of the above-mentioned examples, in the second step, the reaction temperature is 80-90°C, and the reaction time is 10-14h.

[0021] Example 7: The oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained by the following method: a required amount of N'N-dimethylformamide, butyne diol, and emulsifier are added to a required amount of bis-Schiff base quaternary ammonium salt, and after being fully stirred, an intermediate mixture is obtained, a required amount of water-soluble benzotriazole is added to the intermediate mixture, and after being stirred, the oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained.

[0022] Example 8: The oilfield multipurpose high-temperature acidizing corrosion inhibitor, the raw materials include 25 parts of bis-Schiff base quaternary ammonium salt, 55 parts of N'N-dimethylformamide, 4 parts of butyne diol, 5 parts of emulsifier OP-10, and 1 part of water-soluble benzotriazole by weight, is obtained by the following method: a required amount of N'N-dimethylformamide, butyne diol, and emulsifier are added to a required amount of bis-Schiff base quaternary ammonium salt, and after being fully stirred, an intermediate mixture is obtained, a required amount of water-soluble benzotriazole is added to the intermediate mixture, and after being stirred, the oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained. The bis-Schiff base quaternary ammonium salt is obtained by the following method: In the first step, a required amount of salicylaldehyde and 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl] is added to a solvent toluene and stirred to obtain a mixed solution, then acetic acid is added to the mixed solution, and after being reacted at 100°C for 7h, a Schiff base is obtained; wherein 60g of solvent toluene is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl], and 1ml of acetic acid is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl]; In the second step, a required amount of 3-chloro-2-hydroxypropanesulfonic acid sodium salt is added to the Schiff base and mixed, and after being reacted at 80°C for 10h, a bis-Schiff base quaternary ammonium salt is obtained.

[0023] Example 9: The oilfield multipurpose high-temperature acidification corrosion inhibitor, raw materials include 30 parts of double Schiff base quaternary ammonium salt, 60 parts of N'N-dimethylformamide, 6 parts of butyne diol and 10 parts of emulsifier OP-10 and 3 parts of water-soluble benzotriazole by weight, obtained by the following method: to the required amount of double Schiff base quaternary ammonium salt, add the required amount of N'N-dimethylformamide, butyne diol and emulsifier, stir well to get intermediate mixture, to the intermediate mixture, add the required amount of water-soluble benzotriazole, stir to get oilfield multipurpose high-temperature acidification corrosion inhibitor; Wherein, the double Schiff base quaternary ammonium salt is obtained by the following method: First, add the required amount of salicylaldehyde and 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl] to the solvent toluene and stir to get a mixed solution, then add acetic acid to the mixed solution, react at 120℃ for 9h to get the Schiff base; wherein, 70g of solvent toluene is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl], and 2ml of acetic acid is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl]; Second, add the required amount of 3-chloro-2-hydroxypropanesulfonic acid sodium to the Schiff base and mix, react at 90℃ for 14h to get the double Schiff base quaternary ammonium salt.

[0024] Example 10: The oilfield multipurpose high-temperature acidification corrosion inhibitor, raw materials include 27 parts of double Schiff base quaternary ammonium salt, 58 parts of N'N-dimethylformamide, 5 parts of butyne diol and 8 parts of emulsifier OP-10 and 2 parts of water-soluble benzotriazole by weight, obtained by the following method: to the required amount of double Schiff base quaternary ammonium salt, add the required amount of N'N-dimethylformamide, butyne diol and emulsifier, stir well to get intermediate mixture, to the intermediate mixture, add the required amount of water-soluble benzotriazole, stir to get oilfield multipurpose high-temperature acidification corrosion inhibitor; Wherein, the double Schiff base quaternary ammonium salt is obtained by the following method: First, add the required amount of salicylaldehyde and 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl] to the solvent toluene and stir to get a mixed solution, then add acetic acid to the mixed solution, react at 120℃ for 9h to get the Schiff base; wherein, 70g of solvent toluene is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl], and 2ml of acetic acid is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl]; Second, add the required amount of 3-chloro-2-hydroxypropanesulfonic acid sodium to the Schiff base and mix, react at 90℃ for 14h to get the double Schiff base quaternary ammonium salt.

[0025] Compared with the prior art, the present application has the beneficial effects that: Firstly, the oilfield multipurpose high-temperature acidification corrosion inhibitor of the present application uses self-made raw material double-Schiff base quaternary ammonium salt, which has the advantages that, on the one hand, it has multiple hydroxyl groups and excellent water solubility; on the other hand, it has multiple strong adsorption groups such as benzene ring, double bond and amino group in the molecular structure, which can form a dense and firm adsorption film on the metal substrate to reduce the contact between acid liquid and metal and achieve effective protection. Secondly, the raw material of the oilfield multipurpose high-temperature acidification corrosion inhibitor of the present application is further compounded with other small molecular compounds such as N’N-dimethylformamide, butyne diol emulsifier and water-soluble benzotriazole, so that the oilfield multipurpose high-temperature acidification corrosion inhibitor has the characteristics of high efficiency and strong adaptability, and can play an excellent protective role for different acid liquid types and different metals. Thirdly, the raw material of the present application has wide sources, low cost and simple preparation process, and is easy to realize industrialized production.

[0026] Example 11: The double-Schiff base quaternary ammonium salt is obtained by the following method: First step, 53.9g of salicylaldehyde and 38.2g of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl] are added to a three-necked flask connected with a water trap, 65g of solvent toluene is added, stirring is started, then 1ml to 2ml of acetic acid is added dropwise to the three-necked flask, and the temperature is slowly raised to 110℃, and after refluxing at this temperature for 8h without water, the temperature is lowered, and a Schiff base is obtained; wherein the molar ratio of salicylaldehyde and 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidinyl] is 2.4:1; Second step, 78.63g of 3-chloro-2-hydroxypropanesulfonic acid sodium is added to the three-necked flask containing the Schiff base, stirring is started, the temperature is raised to 80℃ to 90℃, and the reaction is carried out for 12h, and then a double-Schiff base quaternary ammonium salt is obtained; the following is a structural schematic diagram of the reaction process of the double-Schiff base quaternary ammonium salt: The oilfield multipurpose high-temperature acidification corrosion inhibitor is obtained by the following method: 58g of N’N-dimethylformamide, 5g of butyne diol and 8g of emulsifier OP-10 are added to 27g of double-Schiff base quaternary ammonium salt, and after stirring, an intermediate mixture is obtained, 2g of water-soluble benzotriazole is added to the intermediate mixture, and after stirring, the oilfield multipurpose high-temperature acidification corrosion inhibitor is obtained.

[0027] The oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 11 was tested for corrosion inhibition effect with reference to SY / T5405-2019 “Performance Test Method and Evaluation Index of Acidizing Corrosion Inhibitor”. The test method was as follows: N80 steel was placed in different types of acid liquid system solutions, 1.0% of the oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 11 was added, the reaction time was 4 hours, and the corrosion rate of the N80 steel was observed after 4 hours. The test results are shown in Table 1. As shown in Table 1, the corrosion rates of the N80 steel in different types of acid liquid system solutions without adding any acidizing corrosion inhibitor were all large and could not be calculated, and the corrosion rates of the N80 steel in different types of acid liquid system solutions with the addition of the oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 12 were all less than 1.0 g / (m 2 ·h), which met the requirements of the industry standard. This indicates that the oilfield multipurpose high-temperature acidizing corrosion inhibitor has good corrosion inhibition performance.

[0028] Embodiment 12 The preparation method of the bis-Schiff base quaternary ammonium salt is the same as that of the embodiment 11.

[0029] The oilfield multipurpose high-temperature acidizing corrosion inhibitor was obtained by the following method. An intermediate mixture was obtained by adding 52 g of N’N-dimethylformamide, 5 g of butyne diol and 10 g of emulsifier OP-10 into 30 g of the bis-Schiff base quaternary ammonium salt and stirring thoroughly, and the oilfield multipurpose high-temperature acidizing corrosion inhibitor was obtained by adding 3 g of water-soluble benzotriazole into the intermediate mixture and stirring.

[0030] The oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 12 was tested for corrosion inhibition effect with reference to SY / T5405-2019 “Performance Test Method and Evaluation Index of Acidizing Corrosion Inhibitor”. The test method was as follows: N80 steel was placed in different concentrations of hydrochloric acid solutions (mass concentrations of 15% and 20%), different concentrations (1.0%, 2.0%, 3.0% and 4.0%) of the oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 12 were added at different temperatures (100°C, 120°C, 140°C and 160°C), the reaction time was 4 hours, and the corrosion rate of the N80 steel was observed after 4 hours. The test results are shown in Table 2. As shown in Table 2, the corrosion rates of the N80 steel in 15% and 20% HCl acid liquid at different temperatures all met the requirements of the industry standard. This indicates that the oilfield multipurpose high-temperature acidizing corrosion inhibitor can effectively protect the N80 steel from corrosion by the hydrochloric acid solution and has good corrosion inhibition performance.

[0031] Embodiment 13 The preparation method of the bis-Schiff base quaternary ammonium salt is the same as that of the embodiment 11.

[0032] The oilfield multipurpose high-temperature acidification corrosion inhibitor is obtained by the following method: After 32 g of the bis-Schiff base quaternary ammonium salt, 50 g of N'N-dimethylformamide, 4 g of butyne glycol, and 12 g of emulsifier OP-10 are fully stirred, an intermediate mixture is obtained. After 2 g of water-soluble benzotriazole is added to the intermediate mixture and stirred, the oilfield multipurpose high-temperature acidification corrosion inhibitor is obtained.

[0033] The oilfield multipurpose high-temperature acidification corrosion inhibitor prepared in Example 13 is tested for corrosion inhibition effect according to SY / T5405-2019 “Performance Test Method and Evaluation Index for Corrosion Inhibitors for Acidification”. The test method is as follows: N80 steel is placed in different concentrations of hydrochloric acid solution and hydrofluoric acid solution, different concentrations (1.0%, 2.0%, 3.0%, and 4.0%) of the oilfield multipurpose high-temperature acidification corrosion inhibitor prepared in Example 13 are added at different temperatures (100℃, 120℃, 140℃, and 160℃), the reaction time is 4 hours, and the corrosion rate of N80 steel is investigated after 4 hours. The test results are shown in Table 3. As shown in Table 3, at different temperatures, the corrosion rate of N80 steel in different concentrations of hydrochloric acid solution and hydrofluoric acid solution is within the range required by the industry. This indicates that the oilfield multipurpose high-temperature acidification corrosion inhibitor can effectively protect N80 steel from corrosion by mixed acid solution of hydrochloric acid solution and hydrofluoric acid solution, and has good corrosion inhibition performance.

[0034] Example 14: The bis-Schiff base quaternary ammonium salt is prepared by the same method as in Example 11.

[0035] The oilfield multipurpose high-temperature acidification corrosion inhibitor is obtained by the following method: After 34 g of the bis-Schiff base quaternary ammonium salt, 46 g of N'N-dimethylformamide, 5 g of butyne glycol, and 12 g of Tween 20 are fully stirred, an intermediate mixture is obtained. After 2 g of water-soluble benzotriazole is added to the intermediate mixture and stirred, the oilfield multipurpose high-temperature acidification corrosion inhibitor is obtained.

[0036] The oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 14 of the present application is tested for corrosion inhibition effect by referring to SY / T5405-2019 “Performance Test Method and Evaluation Index of Acidizing Corrosion Inhibitor”. The test method is as follows: N80 steel is placed in hydrochloric acid solution, hydrofluoric acid solution and acetic acid solution with different concentrations, and the oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 14 of the present application with different concentrations (1.0%, 2.0%, 3.0% and 4.0%) is added at different temperatures (100°C, 120°C, 140°C and 160°C), the reaction time is 4 hours, and the corrosion rate of N80 steel is observed after 4 hours. The test results are shown in Table 4. As shown in Table 4, at different temperatures, the corrosion rates of N80 steel in hydrochloric acid solution, hydrofluoric acid solution and acetic acid solution with different concentrations are all within the range required by the industry. This shows that the oilfield multipurpose high-temperature acidizing corrosion inhibitor of the present application can effectively protect N80 steel from corrosion by mixed acid solution of hydrochloric acid solution, hydrofluoric acid solution and acetic acid solution, and has good corrosion inhibition performance.

[0037] Example 15 The double-Schiff base quaternary ammonium salt is prepared by the same method as in the embodiment 11.

[0038] The oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained by the following method: After 30g of double-Schiff base quaternary ammonium salt, 51g of N’N-dimethylformamide, 5g of butyne diol and 11g of Tween 20 are fully stirred, an intermediate mixture is obtained. After 3g of water-soluble benzotriazole is added to the intermediate mixture and stirred, the oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained.

[0039] The oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 15 of the present application is tested for corrosion inhibition effect by referring to SY / T5405-2019 “Performance Test Method and Evaluation Index of Acidizing Corrosion Inhibitor”. The test method is as follows: different types of steel (N80 steel, P110 steel and J55 steel) are placed in 20% hydrochloric acid solution, and the oilfield multipurpose high-temperature acidizing corrosion inhibitor prepared in the embodiment 15 of the present application with different concentrations (2.0%, 3.0% and 4.0%) is added at different temperatures (120°C, 140°C and 160°C), the reaction time is 4 hours, and the corrosion rates of different types of steel (N80 steel, P110 steel and J55 steel) are observed after 4 hours. The test results are shown in Table 5. As shown in Table 5, the corrosion rates of different types of steel (N80 steel, P110 steel and J55 steel) in 20% hydrochloric acid solution are all within the range required by the industry. This shows that the oilfield multipurpose high-temperature acidizing corrosion inhibitor of the present application can effectively protect various types of steel from corrosion by acid solution, and has good corrosion inhibition performance.

[0040] Comparative Example 1 The single-Schiff base quaternary ammonium salt is obtained by the following method: First step, in the three-port flask with water collector, add 36.6g salicylaldehyde and 63.9g aniline, then add 65g solvent toluene, open the stirring, then, add 1ml to 2ml acetic acid to the three-port flask, slowly warm up to 110℃, reflux for 8h without water, then cool down, get the Schiff base; Second step, add 58.97g 3-chloro-2-hydroxypropanesulfonic acid sodium to the three-port flask with Schiff base, open the stirring, warm up to 80℃ to 90℃, react for 12h, get the single Schiff base quaternary ammonium salt.

[0041] The oilfield multipurpose high-temperature acidification corrosion inhibitor is obtained by the following method: Add 51g N’N-dimethylformamide, 5g butyne diol and 11g Tween 20 to 30g single Schiff base quaternary ammonium salt, fully stir to get the intermediate mixture, then add 3g water-soluble benzotriazole to the intermediate mixture, stir to get the oilfield multipurpose high-temperature acidification corrosion inhibitor.

[0042] According to SY / T5405-2019 "Performance test method and evaluation index of corrosion inhibitor for acidification", the oilfield multipurpose high-temperature acidification corrosion inhibitor prepared by the present application comparative example 1 is tested for corrosion inhibition effect, the test method is the same as that in example 12, N80 steel is respectively placed in 15% and 20% hydrochloric acid solution, different concentrations (1.0%, 2.0%, 3.0% and 4.0%) of the oilfield multipurpose high-temperature acidification corrosion inhibitor prepared by the present application comparative example 1 are added at different temperatures (100℃, 120℃, 140℃ and 160℃), the reaction time is 4 hours, and the corrosion rate of N80 steel is investigated after 4 hours. The test results are shown in Table 6. As shown in Table 6, the corrosion rate of N80 steel in 15% and 20% HCl acid solution at different temperatures is higher than the industry standard requirement, which does not meet the industry requirement. This shows that the oilfield multipurpose high-temperature acidification corrosion inhibitor prepared by the single Schiff base quaternary ammonium salt and other small molecule compounds in the present application comparative example 1 has poor corrosion inhibition performance.

[0043] In summary, according to the test results of examples 11 to 15 and comparative example 1 of the present application, the self-made double Schiff base quaternary ammonium salt can form a dense and firm adsorption film on the metal substrate, reducing the contact between acid and metal to achieve effective protection. At the same time, the raw materials are compounded with other N’N-dimethylformamide, butyne diol emulsifier and water-soluble benzotriazole small molecule compounds, so that the oilfield multipurpose high-temperature acidification corrosion inhibitor has the characteristics of strong adaptability, good temperature resistance and good corrosion inhibition effect for different types of acid.

[0044] The above technical features constitute the examples of the present application, which have strong adaptability and implementation effect. Non-essential technical features can be added or reduced according to actual needs to meet different needs.

Claims

1. A multi-purpose high temperature acidizing corrosion inhibitor for oil field, characterized in that The raw materials include 25-30 parts of bis-Schiff base quaternary ammonium salt, 55-60 parts of N'N-dimethylformamide, 4-6 parts of butyne glycol, 5-10 parts of emulsifier and 1-3 parts of benzotriazole.

2. The oil field multipurpose high temperature acidizing corrosion inhibitor according to claim 1, characterized in that The emulsifier is one of Tween 20 and emulsifier OP-10.

3. The oilfield multipurpose high temperature acidizing corrosion inhibitor according to claim 1 or 2, characterized in that The bis-Schiff base quaternary ammonium salt is obtained by using salicylaldehyde, 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl] and 3-chloro-2-hydroxypropanesulfonic acid sodium in a mass ratio of 2.2-2.4:1:2 as raw materials according to the following method: In the first step, the required amount of salicylaldehyde and 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl] are added to the solvent toluene and stirred to obtain a mixture, then 3-chloro-2-hydroxypropanesulfonic acid sodium is added to the mixture and stirred to obtain a bis-Schiff base quaternary ammonium salt. In the first step, 60-70 g of solvent toluene is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl], and 1-2 ml of acetic acid is added to each mole of 1,3-phenylenediamine-5-[4-(dimethylamino)-1-piperidyl].

4. The oil field multipurpose high temperature acidizing corrosion inhibitor according to claim 3, characterized in that In the first step, the reaction temperature is 100-120℃, and the reaction time is 7-9 h.

5. The oilfield multipurpose high temperature acidizing corrosion inhibitor according to claim 3 or 4, characterized in that In the second step, the reaction temperature is 80-90℃, and the reaction time is 10-14 h.

6. The oilfield multipurpose high temperature acidizing corrosion inhibitor according to claim 3 or 4 or 5, characterized in that The oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained by adding the required amount of N'N-dimethylformamide, butyne glycol and emulsifier to the required amount of bis-Schiff base quaternary ammonium salt and stirring to obtain an intermediate mixture, and then adding the required amount of benzotriazole to the intermediate mixture and stirring to obtain the oilfield multipurpose high-temperature acidizing corrosion inhibitor.

7. The oilfield multipurpose high temperature acidizing corrosion inhibitor according to any one of claims 1 to 6, characterized in that The oilfield multipurpose high-temperature acidizing corrosion inhibitor is obtained by adding the required amount of N'N-dimethylformamide, butyne glycol and emulsifier to the required amount of bis-Schiff base quaternary ammonium salt and stirring to obtain an intermediate mixture, and then adding the required amount of benzotriazole to the intermediate mixture and stirring to obtain the oilfield multipurpose high-temperature acidizing corrosion inhibitor.

8. A method for preparing a multi-purpose high-temperature acidizing corrosion inhibitor for oilfields according to any one of claims 1 to 6, characterized in that... ​

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