Corrosion inhibition-sterilization treatment agent for oil field and preparation method of corrosion inhibition-sterilization treatment agent

Abstract

The invention relates to the technical field of oil field chemical engineering, and particularly discloses a corrosion inhibition-sterilization treatment agent for an oil field and a preparation method of the corrosion inhibition-sterilization treatment agent for the oil field, and the preparation method comprises the following steps: (1) reacting epichlorohydrin, long-chain alkyl tertiary amine and a nitroimidazole compound to obtain imidazole heterocyclic biquaternary ammonium salt; and (2) dissolving the imidazole heterocycle-containing biquaternary ammonium salt in an organic solvent to form an organic phase, dispersing quercetin-lecithin in water to form a water phase, mixing the organic phase and the water phase, adding a compound emulsifier, and uniformly stirring to obtain the corrosion inhibition-sterilization treatment agent for the oil field. According to the invention, the imidazole heterocycle-containing biquaternary ammonium salt is wrapped by quercetin-lecithin to form a core-shell structure, so that not only is the bactericidal performance of the agent improved, but also the corrosion inhibition-sterilization treatment agent is endowed with long-term effectiveness.

Description

Technical Field

[0001] The present application relates to the technical field of oilfield chemical industry, and more specifically, to a corrosion inhibition-sterilization treatment agent for oilfields and a preparation method thereof. Background Art

[0002] With the continuous development of oil fields, the problem of sewage corrosion has caused great trouble to the development of oil fields. Replacing pipelines and equipment will cause production stoppage and material loss. The sewage corrosion of oil fields is generally caused by harmful media such as Cl in the water. - 、HCO3 - It is caused by salt ions, CO2, H2S, O2, and bacteria (sulfate-reducing bacteria, iron bacteria, saprophytes, etc., mainly sulfate-reducing bacteria). Therefore, oil fields can effectively and economically achieve the purpose of corrosion prevention and bacterial control by adding corrosion inhibitors and fungicides to produced fluids and reinjection water. Therefore, adding corrosion inhibitors and fungicides has become a necessary process in many domestic oil fields.

[0003] At present, the corrosion inhibitors commonly used in oil and water treatment processes in oil fields include quaternary ammonium salts, amides, imidazolines, and other organic compounds containing N, P, and S, as well as a few inorganic corrosion inhibitors. Commonly used fungicides include quaternary ammonium salts, diquaternary ammonium salts, polyquaternary ammonium salts, quaternary phosphonium salts, aldehydes, and some heterocyclic compounds. Among them, dodecyldimethylbenzyl ammonium chloride (1227) is the most commonly used and economical and efficient. However, due to drug resistance and other reasons, the use of this type of fungicide in offshore oil fields has gradually increased. Other commonly used fungicides also have similar problems. Therefore, it is necessary to further improve the technology, introduce groups, or compound new substances to improve the effect and reduce drug resistance.

[0004] The patent application document with publication number CN110250194A discloses a composite bactericidal corrosion inhibitor for oil fields and a preparation method thereof. The composite bactericidal corrosion inhibitor comprises, by mass, 18-35 parts of an intermediate, 10-20 parts of glutaraldehyde, 2-8 parts of thiourea, 5-10 parts of an alcohol solvent, and the remainder being water. The preparation method of the intermediate is to add oleic acid, cyclohexane acid and diethylenetriamine into a reactor in proportion to prepare the intermediate. The composite bactericidal corrosion inhibitor for oil fields is prepared by introducing cyclohexanecarboxylic acid imidazoline acetate on the basis of oleic acid imidazoline quaternary ammonium salt, and then compounding thiourea, glutaraldehyde, etc. to form a composite bactericide, in which thiourea is added. Although thiourea, as a sulfur-containing compound, has a strong corrosion inhibition and bactericidal effect, it produces harmful gases and waste during use, causing certain pollution to the environment, limiting its application in offshore oil fields. At the same time, glutaraldehyde itself is flammable and toxic, has a strong irritating odor, can corrode the skin, is prone to combustion and explosion when encountering combustible materials, is volatile, and has no long-term effect. Summary of the Invention

[0005] In order to improve the environmental protection and long-term effectiveness of the corrosion inhibition-sterilization treatment agent, the present application provides a corrosion inhibition-sterilization treatment agent for oil fields and a preparation method thereof.

[0006] In a first aspect, the present application provides a method for preparing a corrosion inhibition-sterilization agent for oil fields, which adopts the following technical solution: A method for preparing a corrosion inhibition-sterilization agent for oil fields comprises the following steps: (1) reacting epichlorohydrin, a long-chain alkyl tertiary amine and a nitroimidazole compound to obtain an imidazole-containing heterocyclic diquaternary ammonium salt; (2) The imidazole heterocyclic diquaternary ammonium salt is dissolved in an organic solvent to form an organic phase, quercetin-lecithin is dispersed in water to form an aqueous phase, the organic phase and the aqueous phase are mixed and a composite emulsifier is added to obtain a corrosion inhibition-sterilization agent for oil fields.

[0007] By adopting the above technical solution, the present application combines a diquaternary ammonium salt fungicide with a nitroimidazole compound to form an imidazole heterocycle-containing diquaternary ammonium salt. The nitrogen atom on the imidazole ring reacts with an active quaternizing agent and a long-chain alkyl group to form the diquaternary ammonium salt, improving its water solubility without destroying the imidazole ring structure. The introduction of a nitrogen-containing heterocyclic group into the diquaternary ammonium salt not only retains the bactericidal properties of the imidazole ring but also significantly enhances its corrosion inhibition performance. In addition to improving the water solubility, surface activity, and bactericidal properties of the imidazole ring compound, this design also imparts excellent corrosion inhibition ability to the new diquaternary ammonium salt compound, achieving the effect of multiple uses with a single dose, low dosage, and excellent bactericidal and corrosion inhibition properties. Furthermore, the compound does not contain thiourea or other sulfur-containing substances, reducing the risk of corrosion in crude oil refining processes. The compound is particularly suitable for bacterial control and anti-corrosion treatment in oil fields, particularly offshore oil fields.

[0008] In addition, quercetin-lecithin has excellent antibacterial effects. The present application forms a core-shell structure by encapsulating the imidazole heterocyclic diquaternary ammonium salt, which not only improves the bactericidal performance of the agent, but also buffers the release of the imidazole heterocyclic diquaternary ammonium salt, reduces its release rate, and prolongs the action time, thereby giving the corrosion inhibition-bactericidal treatment agent long-lasting effect.

[0009] Preferably, the preparation method of the imidazole heterocyclic diquaternary ammonium salt comprises the following steps: Epichlorohydrin is heated to 75-85° C. and maintained at a constant temperature, a long-chain alkyl tertiary amine is added dropwise to the epichlorohydrin, and after the addition is complete, the mixture is stirred for reaction. After the reaction is complete, the mixture is cooled to room temperature to obtain an intermediate; acetonitrile is added to the intermediate and the mixture is heated to reflux under acetonitrile, and then a nitroimidazole compound is added. After the nitroimidazole compound is dissolved, the mixture is refluxed for reaction for 6-10 hours, cooled to room temperature, and distilled under reduced pressure, washed with acetone, filtered, and dried to obtain an imidazole-containing heterocyclic diquaternary ammonium salt; The molar ratio of epichlorohydrin, long-chain alkyl tertiary amine and nitroimidazole compound is 2: (1-1.2): (1-1.3); The mass ratio of epichlorohydrin, acetonitrile and acetone is 1:(2.7-6):(3-5).

[0010] Preferably, the long-chain alkyl tertiary amine is one or more of dodecyldimethyl tertiary amine, tetradecyldimethyl tertiary amine, hexadecyldimethyl tertiary amine, and dodecylbenzylmethyl tertiary amine.

[0011] Preferably, the nitroimidazole compound is one of metronidazole, tinidazole and ornidazole, more preferably ornidazole.

[0012] By adopting the above technical solution, the nitroimidazole compound is a solid, while the selected quaternizing agents are all liquids. At the same time, the first step in the preparation process of the target product is to generate a quaternary ammonium salt solid. If there is no solvent to dissolve the nitroimidazole compound, the next reaction will be difficult to proceed, so a suitable solvent must be selected. Acetonitrile, as a polarizing agent, can not only dissolve the quaternary ammonium salt and the nitroimidazole compound, but is also miscible with the quaternizing agent, thereby enhancing the activity of the quaternizing agent and promoting the quaternization reaction.

[0013] Since the σ bond in nitroimidazole compounds is composed of two electrons and does not have aromaticity, the stability is poor and the ring is easily opened when the temperature is too high or the alkalinity is too strong. Therefore, the reaction temperature should not be too high, and it is more appropriate to control it at around 80°C.

[0014] Epichlorohydrin is used as a linker, and its hydroxyl functional group participates in the reaction, which accelerates the reaction rate.

[0015] Ornidazole is the third generation of nitroimidazole derivatives after metronidazole and tinidazole, and has better bactericidal properties.

[0016] Preferably, the preparation method of the corrosion inhibition-sterilization agent for oil fields comprises the following steps: (1) Epichlorohydrin, long-chain alkyl tertiary amine and nitroimidazole compounds are reacted to obtain an imidazole-containing heterocyclic diquaternary ammonium; (2) The imidazole heterocyclic diquaternary ammonium salt and the pyridinium quaternary ammonium salt are dissolved in an organic solvent to form an organic phase, quercetin-lecithin is dispersed in water to form an aqueous phase, the organic phase and the aqueous phase are mixed and a composite emulsifier is added to obtain a corrosion inhibition-sterilization treatment agent for oil fields.

[0017] By adopting the above technical solution, since nitroimidazole compounds are prone to ring opening when the temperature is too high, the corrosion inhibition and bactericidal effect of the imidazole heterocyclic diquaternary ammonium salt formed when the temperature exceeds 90°C becomes worse; since pyridine is aromatic, stable and resistant to high temperatures, the formed pyridine quaternary ammonium salt has the typical characteristics of cationic surfactants (such as hydrophilic-lipophilic balance, low critical micelle concentration, high surface activity and good compatibility), and at the same time has unique positive charge characteristics and bactericidal properties. Therefore, after compounding the pyridine quaternary ammonium salt with it, the present application found that not only the applicable temperature range of the obtained corrosion inhibitor-bactericide can be broadened, but also it has a better corrosion inhibition and bactericidal effect than a single addition.

[0018] Preferably, the mass ratio of the imidazole heterocyclic diquaternary ammonium salt to the pyridinium quaternary ammonium salt is 1:(1-3).

[0019] Preferably, the preparation method of the quaternary pyridinium ammonium salt comprises the following steps: At 0°C, add alkyl bromide and metallic lithium to anhydrous ether, maintain the reaction at low temperature and stir, then add pyridine and toluene solution, raise the temperature to 110-120°C, and reflux for 6-12 hours to synthesize α-alkylpyridine; α-alkylpyridine and dibromoalkyl halide are mixed in ethanol or propanol solvent, heated to reflux reaction, cooled for crystallization, filtered and dried to obtain quaternary ammonium salt of pyridine; The molar ratio of the alkyl bromide to metallic lithium is 1:(1-3); The molar ratio of the dibromoalkyl halide to the α-alkylpyridine is 1:(2-3).

[0020] By adopting the above technical solution, the preparation method of the present application is easy to operate, has fewer steps and mild reaction conditions. The obtained pyridinium quaternary ammonium salt not only has high surface activity and low critical micelle concentration, but also has excellent bactericidal and corrosion inhibition properties.

[0021] Preferably, the composite emulsifier is a mixture of an emulsifier and an emulsifying aid in a mass ratio of (2-3):1; the emulsifier is a mixture of Span-80 and Tween-80 in a mass ratio of (1-3):(7-9).

[0022] By adopting the above technical solution, Span-80 and Tween-80 have complementary properties. Both are non-ionic surfactants. The combination of Span-80 and Tween-80 can form a more stable emulsification system, improve the dispersibility and emulsification effect of the system; at the same time, the appropriate ratio can maximize the respective characteristics of the two, so that they can achieve the best effect during use.

[0023] The combination of emulsifier and emulsifying aid produces a synergistic effect, which can not only reduce the surface tension, but also serve as a corrosion inhibition-bactericidal adjuvant, further enhancing the corrosion inhibition and bactericidal properties of the corrosion inhibition-bactericidal treatment agent, and synergistically exerting multiple corrosion inhibition-bactericidal effects with imidazole heterocyclic diquaternary ammonium salts and pyridine quaternary ammonium salts.

[0024] Preferably, the emulsifying aid is one or more of dodecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide; further, the emulsifying aid is a mixture of dodecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide in a mass ratio of (5-7): (3-5).

[0025] By adopting the above technical solution, when studying the corrosion inhibition-bactericidal effect of emulsifying agents on oil fields, it was found that the corrosion inhibition-bactericidal film layer formed by imidazole heterocyclic diquaternary ammonium salt and pyridinium quaternary ammonium salt had a large number of defects: when compounded with dodecyltrimethylammonium bromide, due to its relatively small steric hindrance, it can more fully fill the film defects, making the film more dense; when compounded with tetradecyltrimethylammonium bromide, due to the latter's greater steric hindrance, the ability to fill defects is limited, resulting in large gaps in the film layer and poor compounding effect. Therefore, when the two are compounded, due to their steric hindrance differences, they can be staggered to fill the defects of the corrosion inhibition-bactericidal film layer formed by imidazole heterocyclic diquaternary ammonium salt and pyridinium quaternary ammonium salt, jointly improving the corrosion inhibition and bactericidal properties, and showing a good synergistic effect.

[0026] Preferably, the organic solvent is one of N,N-dimethylformamide, N-methylpyrrolidone, acetone or dimethylacetamide.

[0027] In a second aspect, the present application provides a corrosion inhibition-sterilization agent for oil fields, which adopts the following technical solution: The corrosion inhibition-sterilization treatment agent for oil fields is prepared by adopting the above preparation method.

[0028] In summary, this application has the following beneficial effects: 1. The present application effectively combines a diquaternary ammonium salt fungicide with a nitroimidazole compound to form an imidazole heterocycle-containing diquaternary ammonium salt, which not only achieves multi-purpose use with one dose, has a small usage amount, and has excellent bactericidal and corrosion inhibition properties, but also does not contain thiourea and other sulfur-containing substances, thereby reducing the corrosion risk in the crude oil refining process; at the same time, since quercetin-lecithin has excellent antibacterial effects, the core-shell structure is formed by wrapping the imidazole heterocycle-containing diquaternary ammonium salt with quercetin-lecithin, which not only improves the bactericidal property of the prepared agent, but also quercetin-lecithin has a buffering effect on the release of the imidazole heterocycle-containing diquaternary ammonium salt, which can reduce the release rate of the imidazole heterocycle-containing diquaternary ammonium salt and prolong its use time, thereby making the corrosion inhibition-sterilization treatment agent have long-lasting effect.

[0029] 2. The present application compounds pyridine quaternary ammonium salt with imidazole heterocyclic diquaternary ammonium salt, which not only improves the applicable temperature range of the obtained corrosion inhibition-sterilization treatment agent, but also has better corrosion inhibition and sterilization effect than single addition.

[0030] 3. This application utilizes a synergistic effect of compounding emulsifiers and emulsifying aids, which can not only reduce surface tension, but also serve as an adjuvant to enhance the corrosion inhibition-bactericidal performance, further enhancing the bactericidal and corrosion inhibition properties of the corrosion inhibition-bactericidal treatment agent.

[0031] 4. The emulsifying agent of this application is a compound of dodecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide. Due to the difference in steric hindrance between the two, they can be staggered and filled in the defects of the bactericidal-corrosion-inhibiting film layer formed by imidazole heterocyclic diquaternary ammonium salt and pyridine quaternary ammonium salt, thereby jointly improving the corrosion inhibition and bactericidal properties, and having a good synergistic effect. DETAILED DESCRIPTION

[0032] The present application is further described in detail below with reference to the examples. The raw materials involved in the present application can be obtained commercially.

[0033] Preparation Example 1-3 Imidazole-containing heterocyclic diquaternary ammonium salt Preparation Example 1 This preparation example discloses a method for preparing a diquaternary ammonium salt containing an imidazole heterocycle. The specific process is as follows: 0.2 mol of epichlorohydrin is added to a four-necked flask, the temperature is slowly raised to 80°C, 0.1 mol of tetradecyldimethyl tertiary amine is slowly added dropwise to the epichlorohydrin under stirring, the addition is completed over about 3 hours, and heating is stopped; after the solution is cooled, 50 g of acetonitrile is added, the temperature is then raised to 82°C to reflux the acetonitrile, and then 0.1 mol of ornidazole is added to the reaction solution in three portions. After the ornidazole is dissolved, the solution is refluxed for 8 hours until the solution gradually changes from yellow to reddish brown, and cooled; the solvent and unreacted raw materials are evaporated under reduced pressure at room temperature to obtain a crude product, which is then washed with 55.5 g of acetone and filtered to obtain a brown waxy solid product, which is the diquaternary ammonium salt containing an imidazole heterocycle.

[0034] Preparation Example 2 This preparation example discloses a method for preparing a diquaternary ammonium salt containing an imidazole heterocycle. The specific process is as follows: 0.2 mol of epichlorohydrin is added to a four-necked flask, the temperature is slowly raised to 80°C, 0.11 mol of tetradecyldimethyl tertiary amine is slowly added dropwise to the epichlorohydrin under stirring, the addition is completed over about 3 hours, and heating is stopped; after the solution is cooled, 83.3 g of acetonitrile is added, the temperature is raised to reflux of the acetonitrile, and then 0.115 mol of ornidazole is added to the reaction solution in three portions. After the ornidazole is dissolved, the solution is refluxed for 8 hours until the solution gradually changes from yellow to reddish brown, and cooled; the solvent and unreacted raw materials are evaporated under reduced pressure at room temperature to obtain a crude product, which is then washed with 74 g of acetone and filtered to obtain a brown waxy solid product, which is the diquaternary ammonium salt containing an imidazole heterocycle.

[0035] Preparation Example 3 This preparation example discloses a method for preparing a diquaternary ammonium salt containing an imidazole heterocycle. The specific process is as follows: 0.2 mol of epichlorohydrin is added to a four-necked flask, the temperature is slowly raised to 80° C., 0.12 mol of tetradecyldimethyl tertiary amine is slowly added dropwise to the epichlorohydrin under stirring, the addition is completed over about 3 hours, and heating is stopped; after the solution is cooled, 111 g of acetonitrile is added, the temperature is raised to reflux of the acetonitrile, and then 0.13 mol of ornidazole is added to the reaction solution in three portions. After the ornidazole is dissolved, the solution is refluxed for 8 hours until the solution gradually changes from yellow to reddish brown, and cooled; the solvent and unreacted raw materials are evaporated under reduced pressure at room temperature to obtain a crude product, which is then washed with 92.5 g of acetone and filtered to obtain a brown waxy solid product, which is the diquaternary ammonium salt containing an imidazole heterocycle.

[0036] Preparation Example 4-6 Pyridinium Quaternary Ammonium Salt Preparation Example 4 This preparation example discloses a method for preparing a quaternary ammonium salt of pyridinium, and the specific steps are as follows: After purging a three-necked flask with nitrogen, add 100 mL of anhydrous ether and 0.4 mol of lithium. While stirring, add dropwise a mixture of 0.2 mol of bromododecane and 50 mL of anhydrous ether. Let the reaction proceed for 1 hour to complete the reaction of the lithium. Control the reaction temperature near the freezing point, then add dropwise 0.26 mol of pyridine and 50 mL of toluene. After 2 hours of reaction, raise the temperature to 110°C, and reflux for 3 hours. Separate the liquids, wash, and dry in sequence. Evaporate the low-boiling-point compounds, collect the corresponding fractions by vacuum distillation, and then subject them to column chromatography (eluent: petroleum ether:ethyl acetate = 4:1) to obtain α-alkylpyridine. 2.4 mol of α-alkylpyridine and 1 mol of 1,4-dibromobutane were dissolved in anhydrous ethanol, heated to 80°C and refluxed for 48 hours, the anhydrous ethanol was evaporated, and then anhydrous acetone was added and frozen and recrystallized twice to obtain a white solid. In the presence of phosphorus pentoxide, the solid was dried under reduced pressure at room temperature for 24 hours to obtain a quaternary ammonium salt of pyridine.

[0037] Preparation Example 5 This preparation example discloses a method for preparing a quaternary ammonium salt of pyridinium, and the specific steps are as follows: After purging a three-necked flask with nitrogen, add 50 mL of anhydrous ether and 0.2 mol of lithium. While stirring, add dropwise a mixture of 0.2 mol of bromododecane and 50 mL of anhydrous ether. Let the reaction proceed for 1 hour to complete the lithium reaction. Control the reaction temperature near the freezing point, then add dropwise 0.26 mol of pyridine and 50 mL of toluene. After 2 hours of reaction, raise the temperature to 110°C, and reflux for 3 hours. Separate the liquid, wash, and dry the mixture in sequence. Evaporate the low-boiling-point compound, collect the corresponding fraction by vacuum distillation, and then subject it to column chromatography (eluent: petroleum ether:ethyl acetate = 4:1) to obtain α-alkylpyridine. 2 mol of α-alkylpyridine and 1 mol of 1,4-dibromobutane were dissolved in anhydrous ethanol, heated to 80°C and refluxed for 48 hours, the anhydrous ethanol was evaporated, and then anhydrous acetone was added and frozen and recrystallized twice to obtain a white solid. In the presence of phosphorus pentoxide, the solid was dried under reduced pressure at room temperature for 24 hours to obtain a quaternary ammonium salt of pyridine.

[0038] Preparation Example 6 This preparation example discloses a method for preparing a quaternary ammonium salt of pyridinium, and the specific steps are as follows: After purging a three-necked flask with nitrogen, add 150 mL of anhydrous ether and 0.6 mol of lithium. While stirring, add dropwise a mixture of 0.2 mol of bromododecane and 50 mL of anhydrous ether. Let the reaction proceed for 1 hour to complete the lithium reaction. Control the reaction temperature near the freezing point, then add dropwise 0.26 mol of pyridine and 50 mL of toluene. After reacting for 2 hours, raise the temperature to 110°C, and reflux for 3 hours. Separate the liquid, wash, and dry the mixture in sequence. Evaporate the low-boiling-point compound, collect the corresponding fraction by vacuum distillation, and then subject it to column chromatography (eluent: petroleum ether:ethyl acetate = 4:1) to obtain α-alkylpyridine. 3 mol of α-alkylpyridine and 1 mol of 1,4-dibromobutane were dissolved in anhydrous ethanol, heated to 80°C and refluxed for 48 hours, the anhydrous ethanol was evaporated, and then anhydrous acetone was added and frozen and recrystallized twice to obtain a white solid. In the presence of phosphorus pentoxide, the solid was dried under reduced pressure at room temperature for 24 hours to obtain a quaternary ammonium salt of pyridine.

[0039] Example 1 This embodiment provides a method for preparing a corrosion inhibition-sterilization agent for oil fields, comprising the following steps: (1) Dissolve 100 g of imidazole-containing heterocyclic quaternary ammonium salt in 600 g of N,N-dimethylformamide to form an organic phase; (2) Dissolve 500 g of quercetin-lecithin in 1 L of methanol, place in a flask, evaporate to obtain a uniform lipid dry film, add 2 L of distilled water, and sonicate in a water bath for 30 min to form an aqueous phase; (3) After mixing the organic phase with the aqueous phase, the mixture was stirred and intermittently ultrasonicated in a water bath (2 min each time, 30 s interval, 10 cycles). After stopping the ultrasonication, the mixture was stirred for 2 h and then filtered through a 0.5 μm microporous membrane to obtain sustained-release nanospheres. (4) Add 200 g of slow-release nanospheres to 10 g of composite emulsifier and homogenize at room temperature for 1 h under a pressure of 40 MPa to obtain a corrosion inhibition-sterilization agent for oil fields.

[0040] Among them, the preparation method of quercetin-lecithin is as follows: 0.0488g of lecithin is dissolved in 50mL of tetrahydrofuran to obtain a light yellow clear solution, and then 0.0244g of quercetin is added and fully dissolved, and refluxed for 4h under heating in a water bath, and the temperature is controlled at 55°C. After the reaction is completed, the solution is distilled under reduced pressure and methanol is added, filtered, and the filtrate is further distilled under reduced pressure and n-hexane is added to obtain a precipitate, filtered, and the precipitate is washed with n-hexane, and dried in a vacuum drying oven at 40°C for 3h to obtain quercetin-lecithin.

[0041] The composite emulsifier is 0.7 g of Span-80, 6 g of Tween-80 and 1 g of dodecyltrimethylammonium bromide.

[0042] The imidazole-containing heterocyclic quaternary ammonium salt is from Preparation Example 1.

[0043] Example 2 The difference between this embodiment and embodiment 1 is that the heterocyclic quaternary ammonium salt containing imidazole comes from Preparation Example 2.

[0044] Other details are the same as in Example 1.

[0045] Example 3 The difference between this embodiment and embodiment 1 is that the heterocyclic quaternary ammonium salt containing imidazole comes from Preparation Example 3.

[0046] Other details are the same as in Example 1.

[0047] Example 4 This embodiment provides a method for preparing a corrosion inhibition-sterilization agent for oil fields, comprising the following steps: (1) Dissolve 50 g of imidazole heterocyclic quaternary ammonium salt and 50 g of pyridinium quaternary ammonium salt in 600 g of N,N-dimethylformamide to form an organic phase; (2) Dissolve 500 g of quercetin-lecithin in 1 L of methanol, place in a flask, evaporate to obtain a uniform lipid dry film, add 2 L of distilled water, and sonicate in a water bath for 30 min to form an aqueous phase; (3) After mixing the organic phase with the aqueous phase, the mixture was stirred and intermittently ultrasonicated in a water bath (2 min each time, 30 s interval, 10 cycles). After stopping the ultrasonication, the mixture was stirred for 2 h and then filtered through a 0.5 μm microporous membrane to obtain sustained-release nanospheres. (4) Add 200 g of slow-release nanospheres to 10 g of composite emulsifier and homogenize at room temperature for 1 h under a pressure of 40 MPa to obtain a corrosion inhibition-sterilization agent for oil fields.

[0048] The composite emulsifier is 0.7 g of Span-80, 6 g of Tween-80 and 1 g of dodecyltrimethylammonium bromide.

[0049] The imidazole heterocyclic quaternary ammonium salt is from Preparation Example 2, and the pyridine quaternary ammonium salt is from Preparation Example 4.

[0050] Example 5 The difference between this embodiment and embodiment 1 is that the quaternary ammonium salt of pyridinium comes from Preparation Example 5.

[0051] Other details are the same as in Example 4.

[0052] Example 6 The difference between this embodiment and embodiment 1 is that the quaternary ammonium salt of pyridinium comes from Preparation Example 6.

[0053] Other details are the same as in Example 4.

[0054] Example 7 The difference between this embodiment and embodiment 5 is that: (1) 33 g of imidazole heterocyclic quaternary ammonium salt and 67 g of pyridinium quaternary ammonium salt are dissolved in 600 g of N,N-dimethylformamide to form an organic phase; Other details are the same as in Example 5.

[0055] Example 8 The difference between this embodiment and embodiment 5 is that: (2) 25 g of imidazole heterocyclic quaternary ammonium salt and 75 g of pyridine quaternary ammonium salt are dissolved in 600 g of N,N-dimethylformamide to form an organic phase.

[0056] Other details are the same as in Example 5.

[0057] Example 9 This embodiment provides a method for preparing a corrosion inhibition-sterilization agent for oil fields, comprising the following steps: (1) dissolving 33 g of imidazole heterocyclic quaternary ammonium salt and 67 g of pyridinium quaternary ammonium salt in 600 g of N,N-dimethylformamide to form an organic phase; (2) Dissolve 500 g of quercetin-lecithin in 1 L of methanol, place in a flask, evaporate to obtain a uniform lipid dry film, add 2 L of distilled water, and sonicate in a water bath for 30 min to form an aqueous phase; (3) After mixing the organic phase with the aqueous phase, the mixture was stirred and intermittently ultrasonicated in a water bath (2 min each time, 30 s interval, 10 cycles). After stopping the ultrasonication, the mixture was stirred for 2 h and then filtered through a 0.5 μm microporous membrane to obtain sustained-release nanospheres. (4) Add 200 g of slow-release nanospheres to 10 g of composite emulsifier and homogenize at room temperature for 1 h under a pressure of 40 MPa to obtain a corrosion inhibition-sterilization agent for oil fields.

[0058] The composite emulsifier is a mixture of 0.7 g of Span-80, 6 g of Tween-80 and 1 g of tetradecyltrimethylammonium bromide.

[0059] The imidazole heterocyclic quaternary ammonium salt is from Preparation Example 2, and the pyridine quaternary ammonium salt is from Preparation Example 4.

[0060] Example 10 The difference between this embodiment and embodiment 9 is that the composite emulsifier is 0.7 g of Span-80, 6 g of Tween-80, 0.5 g of dodecyltrimethylammonium bromide and 0.5 g of tetradecyltrimethylammonium bromide.

[0061] Other details are the same as in Example 9.

[0062] Example 11 The difference between this embodiment and embodiment 9 is that the composite emulsifier is 0.7 g of Span-80, 6 g of Tween-80, 0.6 g of dodecyltrimethylammonium bromide and 0.4 g of tetradecyltrimethylammonium bromide.

[0063] Other details are the same as in Example 9.

[0064] Example 12 The difference between this embodiment and embodiment 9 is that the composite emulsifier is 0.7 g of Span-80, 6 g of Tween-80, 0.7 g of dodecyltrimethylammonium bromide and 0.3 g of tetradecyltrimethylammonium bromide.

[0065] Other details are the same as in Example 9.

[0066] Example 13 The difference between this embodiment and embodiment 9 is that the composite emulsifier is 1.43 g of Span-80, 5.71 g of Tween-80, 1.72 g of dodecyltrimethylammonium bromide and 1.14 g of tetradecyltrimethylammonium bromide.

[0067] Other details are the same as in Example 9.

[0068] Example 14 The difference between this embodiment and embodiment 9 is that the composite emulsifier is 2.25 g of Span-80, 5.25 g of Tween-80, 1.5 g of dodecyltrimethylammonium bromide and 1 g of tetradecyltrimethylammonium bromide.

[0069] Other details are the same as in Example 9.

[0070] Comparative Example 1 The corrosion inhibition-sterilization agent used in this comparative example is a diquaternary ammonium salt containing an imidazole heterocycle, wherein the diquaternary ammonium salt containing an imidazole heterocycle is from Preparation Example 1.

[0071] Comparative Example 2 The corrosion inhibition-sterilization agent used in this comparative example for oil fields is pyridinium quaternary ammonium salt, wherein the pyridinium quaternary ammonium salt is from Preparation Example 4.

[0072] Comparative Example 3 The corrosion inhibition-sterilization agent for oil fields used in this comparative example is a mixture of an imidazole heterocyclic quaternary ammonium salt and a pyridine quaternary ammonium salt in a mass ratio of 1:1, wherein the imidazole heterocyclic quaternary ammonium salt is from Preparation Example 1 and the pyridine quaternary ammonium salt is from Preparation Example 4.

[0073] Performance testing The corrosion inhibition-sterilization treatment agent prepared in each example and comparative example was diluted 1000 times with distilled water to obtain an agent.

[0074] (1) Sterilization experiment The water was injected from an oilfield injection station. Sulfate-reducing bacteria (SRB), saprophytic bacteria (TGB), and iron bacteria (FB) were cultured in the laboratory and used as experimental strains. The bactericidal rate was evaluated according to Q / SY 17049-2020. 30 mg / L of the agent was added. The test results are shown in Table 1.

[0075] (2) Corrosion inhibition experiment The water is the injection water of an oilfield injection station. The corrosion inhibition rate is evaluated according to Q / SY 17126-2019. 50 mg / L of the agent is added. The corrosion inhibition rate % = (corrosion rate without corrosion inhibitor added - corrosion rate) / corrosion rate without corrosion inhibitor added. The test results are shown in Table 1.

[0076] (3) Sustained-release experiment Based on the corrosion inhibition efficiency of more than 80%, the corrosion inhibition cycle time of the oil field corrosion inhibition-sterilization treatment agent prepared in each embodiment and comparative example was tested on the basis of the corrosion inhibition experiment.

[0077] Table 1 Performance test data of Examples 1-14 and Comparative Examples 1-3

[0078] In combination with Example 1 and Comparative Example 1 or Example 4 and Comparative Example 3 and with reference to Table 1, it can be seen that the bactericidal effect of the corrosion inhibition-sterilization treatment agent prepared in the embodiment is better than that of the comparative example, and the agent has a long-lasting effect; it shows that the present application forms a core-shell structure with an imidazole heterocyclic diquaternary ammonium salt and quercetin-lecithin, and utilizes the antibacterial effect of quercetin-lecithin itself to improve the bactericidal property of the agent, and after quercetin-lecithin wraps the imidazole heterocyclic diquaternary ammonium salt, the release rate of the imidazole heterocyclic diquaternary ammonium salt can be reduced, and its use time can be extended, thereby making the corrosion inhibition-sterilization treatment agent have a long-lasting effect.

[0079] It can be seen from Examples 1 and 4 or Comparative Examples 1-3 that the present application improves the bactericidal and corrosion-inhibiting properties of the resulting corrosion inhibition-bactericidal treatment agent by compounding a diquaternary ammonium salt containing an imidazole heterocycle and a pyridinium quaternary ammonium salt. Since nitroimidazole compounds are prone to ring opening when the temperature is too high, the corrosion inhibition effect of the imidazole heterocycle diquaternary ammonium salt formed when the temperature exceeds 90°C deteriorates; since pyridine has aromaticity, it has good stability and good high temperature resistance, and the formed pyridinium quaternary ammonium salt has high surface activity and good compounding properties. After compounding the pyridinium quaternary ammonium salt with it, it was found that not only the applicable temperature range of the resulting corrosion inhibition-bactericide can be improved, but also a better corrosion inhibition and bactericidal effect can be achieved compared to the addition of a single substance.

[0080] It can be seen from Examples 7, 9 and 10 that the emulsifying agent used in the present application is a mixture of dodecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide, which can further improve the bactericidal and corrosion-inhibiting properties of the obtained corrosion inhibition-sterilization treatment agent. The bactericidal-corrosion-inhibiting film layer formed by imidazole heterocyclic diquaternary ammonium salt and pyridinium quaternary ammonium salt has a large number of defects. When compounded with dodecyltrimethylammonium bromide, due to the relatively small steric hindrance of dodecyltrimethylammonium bromide, it can more fully fill the defects of the bactericidal-corrosion-inhibiting film layer formed by imidazole heterocyclic diquaternary ammonium salt and pyridinium quaternary ammonium salt, making the film layer more dense; when the imidazole heterocyclic diquaternary ammonium salt and pyridinium quaternary ammonium salt are compounded with tetradecyltrimethylammonium bromide, tetradecyltrimethylammonium bromide is larger than dodecyltrimethylammonium bromide, and its ability to fill defects is limited, resulting in larger gaps in the film layer, resulting in poor compounding effect; however, when dodecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide are compounded, due to the difference in steric hindrance between the two, they can be staggered and filled in the defects of the bactericidal-corrosion-inhibiting film layer formed by imidazole heterocyclic diquaternary ammonium salt and pyridinium quaternary ammonium salt, jointly improving the corrosion inhibition and bactericidal properties, and having a good synergistic effect.

[0081] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A method for preparing a corrosion inhibition-sterilization agent for oil fields, characterized in that: The following steps are involved: (1) reacting epichlorohydrin, a long-chain alkyl tertiary amine and a nitroimidazole compound to obtain an imidazole-containing heterocyclic diquaternary ammonium salt; (2) The imidazole heterocyclic diquaternary ammonium salt is dissolved in an organic solvent to form an organic phase, quercetin-lecithin is dispersed in water to form an aqueous phase, the organic phase and the aqueous phase are mixed and a composite emulsifier is added to obtain a corrosion inhibition-sterilization agent for oil fields.

2. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 1, characterized in that: The preparation method of the imidazole heterocyclic diquaternary ammonium salt comprises the following steps: Epichlorohydrin is heated to 75-85° C. and maintained at a constant temperature, a long-chain alkyl tertiary amine is added dropwise to the epichlorohydrin, and after the addition is complete, the mixture is stirred for reaction. After the reaction is complete, the mixture is cooled to room temperature to obtain an intermediate; acetonitrile is added to the intermediate and the mixture is heated to reflux under acetonitrile, and then a nitroimidazole compound is added. After the nitroimidazole compound is dissolved, the mixture is refluxed for reaction for 6-10 hours, cooled to room temperature, and distilled under reduced pressure, washed with acetone, filtered, and dried to obtain an imidazole-containing heterocyclic diquaternary ammonium salt; The molar ratio of epichlorohydrin, long-chain alkyl tertiary amine and nitroimidazole compound is 2: (1-1.2): (1-1.3); The mass ratio of epichlorohydrin, acetonitrile and acetone is 1:(2.7-6):(3-5).

3. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 2, characterized in that: The long-chain alkyl tertiary amine is one or more of dodecyldimethyl tertiary amine, tetradecyldimethyl tertiary amine, hexadecyldimethyl tertiary amine, and dodecylbenzylmethyl tertiary amine.

4. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 2, characterized in that: The nitroimidazole compound is one of metronidazole, tinidazole and ornidazole.

5. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 1, characterized in that: The following steps are involved: (1) reacting epichlorohydrin, a long-chain alkyl tertiary amine and a nitroimidazole compound to obtain an imidazole-containing heterocyclic diquaternary ammonium salt; (2) dissolving the imidazole heterocyclic diquaternary ammonium salt and the pyridinium quaternary ammonium salt in an organic solvent to form an organic phase, dispersing quercetin-lecithin in water to form an aqueous phase, mixing the organic phase and the aqueous phase and adding a composite emulsifier to obtain a corrosion inhibition-sterilization agent for oil fields; The mass ratio of the imidazole heterocyclic diquaternary ammonium salt to the pyridinium quaternary ammonium salt is 1:(1-3).

6. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 5, characterized in that: The preparation method of the pyridinium quaternary ammonium salt comprises the following steps: At 0°C, add alkyl bromide and metallic lithium to anhydrous ether, maintain the reaction at low temperature and stir, then add pyridine and toluene solution, raise the temperature to 110-120°C, and reflux for 6-12 hours to synthesize α-alkylpyridine; α-alkylpyridine and dibromoalkyl halide are mixed in ethanol or propanol solvent, heated to reflux reaction, cooled for crystallization, filtered and dried to obtain quaternary ammonium salt of pyridine; The molar ratio of the alkyl bromide to metallic lithium is 1:(1-3); The molar ratio of the dibromoalkyl halide to the α-alkylpyridine is 1:(2-3).

7. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 1, characterized in that: The composite emulsifier is a mixture of an emulsifier and an emulsifying aid in a mass ratio of (2-3):1; the emulsifier is a mixture of Span-80 and Tween-80 in a ratio of (1-3):(7-9); and the emulsifying aid is one or more of dodecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide.

8. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 7, characterized in that: The emulsifying aid is a mixture of dodecyltrimethylammonium bromide and tetradecyltrimethylammonium bromide in a mass ratio of (5-7): (3-5).

9. The method for preparing the corrosion inhibition-sterilization agent for oil fields according to claim 1, characterized in that: The organic solvent is one of N,N-dimethylformamide, N-methylpyrrolidone, acetone or dimethylacetamide.

10. Oilfield corrosion inhibition-sterilization agent, characterized in that: The oilfield corrosion inhibition-bactericidal treatment agent is prepared by the preparation method of any one of claims 1 to 9.

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