A high temperature acidification corrosion inhibitor and its preparation method and application

Abstract

The present invention belongs to the field of oil production technology, and in particular to a high-temperature acidification corrosion inhibitor and its preparation method and application. The preparation method is as follows: 1-aza-18-crown-ether-6, methanol, a reducing agent, benzaldehyde-2,4-disulfonate sodium are sequentially added into a reactor, stirred evenly, adjusted to pH 2-3 with hydrochloric acid, and heated to a temperature-insulating reaction; 2,3-dimethoxybenzyl chloride is added into the above-mentioned reactor, pH 8-9 is adjusted with sodium hydroxide, heated to reflux, and vacuum distillation is performed to obtain a viscous solid, which is recrystallized from cyclohexane to obtain a solid, dried at 105 ° C overnight, and a product high-temperature acidification corrosion inhibitor is obtained. Based on 1 molar portion of 1-aza-18-crown-ether-6, the amounts of benzaldehyde-2,4-disulfonate and 2,3-dimethoxybenzyl chloride are 0.8-1.2 and 0.8-1.2 molar portions, respectively. The acidification corrosion inhibitor of the present invention has the advantages of high temperature resistance and good corrosion inhibition effect.

Description

Technical Field

[0001] The invention belongs to the technical field of petroleum extraction, and in particular relates to a high-temperature acidizing corrosion inhibitor and a preparation method and application thereof. Background Art

[0002] During the production of oil and gas wells, fracturing and acidizing technology is a very effective measure to increase production. Its principle is to inject acidizing fracturing fluid into the formation through the oil well tubing. The acidizing fracturing fluid reacts with the limestone and other components in the formation to produce soluble substances. At the same time, under the action of high pressure, the porosity of the formation is increased. When the soluble substances are discharged from the formation with the acid, the permeability of the oil-producing layer is increased, thereby achieving the purpose of increasing production.

[0003] In this process, the acid used mainly includes strong acids such as hydrochloric acid and hydrofluoric acid. The corrosion of metal by acid will not only damage ground equipment and downhole pipelines, but also the large amount of iron ions corroded will form iron oxide precipitation under certain conditions, affecting the acidizing effect. Sometimes it may also lead to reduced strength and thinning of the equipment, and may eventually cause perforation and rupture of the equipment, resulting in serious economic losses. Therefore, adding corrosion inhibitors to the acidizing fracturing fluid is a necessary anti-corrosion measure.

[0004] Acidizing corrosion inhibitors are chemical substances or mixtures of chemical substances that, when present in the environment at appropriate concentrations and forms, can prevent or slow down corrosion. They minimize acid corrosion on equipment, extend pipeline life, and ensure smooth acidizing operations. The quality of acidizing corrosion inhibitors is crucial to the success of acidizing operations.

[0005] CN104449653A discloses an acidifying corrosion inhibitor and its preparation and application; the composition is as follows: 23-25 ​​parts of ketone, 24-26 parts of aldehyde, and 9-11 parts of acid are added to a reactor in sequence by weight, the pH of the reaction liquid system is adjusted to 4, the stirrer is started, the temperature is gradually raised to 100°C, and the temperature is maintained for 30 minutes. Then, 6-21 parts of alcoholamine are added to the reactor, and the temperature is maintained at 100°C for 2 hours. After the material cools, 35-37 parts of alcohol are added, and the reactor is discharged to obtain the product. However, the corrosion inhibitor has complex components, and the product is a Mannich base with poor water solubility. Therefore, a large amount of ethanol is added as a solvent, which increases the cost. Ethanol is flammable and volatile, and its vapor can form an explosive mixture with air.

[0006] CN113278409B discloses a high-temperature acidizing corrosion inhibitor, belonging to the field of oil and gas field corrosion protection technology. The corrosion inhibitor comprises a main corrosion inhibitor, auxiliary agent A, and auxiliary agent B. The mass ratio of the main corrosion inhibitor, auxiliary agent A, and auxiliary agent B is 10:3:1. The main corrosion inhibitor, auxiliary agent A, and auxiliary agent B are mixed to form the corrosion inhibitor, which is dissolved in ethanol to form a corrosion inhibitor solution. The main corrosion inhibitor is prepared by reacting cyanoguanidine, 4-(((4-chloropyridin-2-yl)oxy)methyl)benzonitrile, and potassium hydroxide in ethylene glycol monoethyl ether at 120°C for 2 hours to produce the product 6-(4-(((4-chloropyridin-2-yl)oxy)methyl)benzonitrile)1,3,5-triazine-2,4,diamine, which is the main corrosion inhibitor. Auxiliary agent B is prepared by reacting N,N-dimethylamine and oxalic acid in the presence of a catalyst at 90°C for 6 hours. However, the invention adds 5wt% corrosion inhibitor to 20wt% hydrochloric acid solution at 180℃, and the corrosion rate is greater than 50g / (m 2 h), the corrosion inhibition effect needs to be improved. Summary of the Invention

[0007] The present invention addresses the deficiencies of the above-mentioned prior art and provides a high-temperature acidizing corrosion inhibitor, a preparation method and an application thereof. The acidizing corrosion inhibitor of the present invention has the advantages of high temperature resistance and good corrosion inhibition effect.

[0008] To achieve the above objectives:

[0009] In a first aspect, the present invention discloses a method for preparing a high-temperature acidizing corrosion inhibitor, wherein the specific steps of the preparation method are as follows:

[0010] (1) Add 1-aza-18-crown-6, methanol, reducing agent, and sodium benzaldehyde-2,4-disulfonate into a reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, and heat and keep the reaction;

[0011] (2) 2,3-dimethoxybenzyl chloride was added to the above reactor, the pH was adjusted to 8-9 with sodium hydroxide, the mixture was heated to reflux, and vacuum distillation was performed to obtain a viscous solid, which was recrystallized with cyclohexane to obtain a solid, and the solid was dried at 105° C. overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0012] In the present invention, preferably, based on 1 mole of 1-aza-18-crown-6, the amounts of sodium benzaldehyde-2,4-disulfonate and 2,3-dimethoxybenzyl chloride are 0.8-1.2 and 0.8-1.2 mole parts, respectively.

[0013] More preferably, based on 1 mole of 1-aza-18-crown-6, the amounts of sodium benzaldehyde-2,4-disulfonate and 2,3-dimethoxybenzyl chloride are 0.9-1.1 and 0.9-1.1 mole parts, respectively.

[0014] In the present invention, preferably, the mass ratio of methanol to 1-aza-18-crown-6 in step (1) is 20-30:1.

[0015] In the present invention, preferably, the reducing agent in step (1) is one of sodium borohydride, sodium triacetoxyborohydride and sodium cyanoborohydride.

[0016] More preferably, the reducing agent is one of sodium triacetoxyborohydride and sodium cyanoborohydride.

[0017] In the present invention, preferably, the mass ratio of the reducing agent to 1-aza-18-crown-6 is 0.2-0.8:1.

[0018] In the present invention, preferably, the temperature of the heating and heat preservation reaction in step (1) is 50-60° C. and the time is 1-4 h.

[0019] In the present invention, preferably, the heating reflux time in step (2) is 12-48 hours.

[0020] The reaction equation for the synthesis of the high-temperature acidification corrosion inhibitor of the present invention is as follows:

[0021]

[0022] In another aspect, the present invention discloses a high-temperature acidizing corrosion inhibitor, the molecular structure of which is as follows:

[0023]

[0024] The third object of the present invention is to disclose the application of the above-mentioned high-temperature acidizing corrosion inhibitor in oil field acidizing fracturing.

[0025] The high-temperature acidification corrosion inhibitor molecules of the present invention contain quaternary ammonium salts, which have a strong positive charge and can be adsorbed on metal surfaces, forming a protective film on the metal surface. The 2,3-dimethoxybenzyl group has a hydrophobic structure, which can slow the approach of acidic aqueous phases to the metal surface. The crown ether can encapsulate iron ions, preventing the iron ions generated by corrosion from escaping with the acid solution, thus preventing further corrosion. The S and O groups of the sulfonic acid group have lone pairs of electrons, which can be adsorbed on the metal surface through various means, such as electrostatic adsorption and the formation of coordinate bonds, forming a more solid protective film.

[0026] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0027] (1) The high-temperature acidification corrosion inhibitor of the present invention is adaptable to different temperature ranges and has a good corrosion inhibition effect from 60-180°C;

[0028] (2) The high temperature acidification corrosion inhibitor of the present invention has a good corrosion inhibition effect. When 5 wt% of the corrosion inhibitor is added to a 20 wt% hydrochloric acid solution at 180°C, the corrosion rate is lower than 15 g / (m 2 ·h); When 6wt% corrosion inhibitor is added to 12wt% hydrochloric acid + 3wt% hydrofluoric acid solution at 180℃, the corrosion rate is lower than 22g / (m 2 ·h). DETAILED DESCRIPTION

[0029] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0030] The present invention will be further described below with reference to specific embodiments:

[0031] Example 1

[0032] (1) Add 20 mmol of 1-aza-18-crown-6, 105.2 g of methanol, 1.05 g of sodium borohydride, and 16 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 50°C, and keep the reaction for 2 h.

[0033] (2) 16 mmol of 2,3-dimethoxybenzyl chloride was added to the above reactor, the pH was adjusted to 8-9 with sodium hydroxide, and the mixture was heated under reflux for 12 h. A viscous solid was obtained by distillation under reduced pressure, and the solid was recrystallized with cyclohexane. The solid was dried at 105° C. overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0034] Example 2

[0035] (1) Add 20 mmol of 1-aza-18-crown ether-6, 107 g of methanol, 1.83 g of sodium borohydride, and 24 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 55°C, and keep the reaction warm for 3 hours.

[0036] (2) 17 mmol of 2,3-dimethoxybenzyl chloride was added to the above reactor, the pH was adjusted to 8-9 with sodium hydroxide, and the mixture was heated under reflux for 24 h. A viscous solid was obtained by distillation under reduced pressure, and the solid was recrystallized with cyclohexane. The solid was dried at 105° C. overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0037] Example 3

[0038] (1) Add 20 mmol of 1-aza-18-crown ether-6, 118 g of methanol, 1.96 g of sodium borohydride, and 17 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 60°C, and keep the reaction for 1 hour.

[0039] (2) Add 24 mmol of 2,3-dimethoxybenzyl chloride to the above reactor, adjust the pH to 8-9 with sodium hydroxide, heat and reflux for 32 hours, and distill under reduced pressure to obtain a viscous solid. Recrystallize with cyclohexane to obtain a solid, and dry it at 105°C overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0040] Example 4

[0041] (1) Add 20 mmol of 1-aza-18-crown ether-6, 152 g of methanol, 2.14 g of sodium borohydride, and 23 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 52 ° C, and keep the reaction for 4 hours.

[0042] (2) 18 mmol of 2,3-dimethoxybenzyl chloride was added to the above reactor, the pH was adjusted to 8-9 with sodium hydroxide, and the mixture was heated under reflux for 36 h. A viscous solid was obtained by distillation under reduced pressure, and the solid was recrystallized with cyclohexane. The solid was dried at 105° C. overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0043] Example 5

[0044] (1) Add 20 mmol of 1-aza-18-crown-6, 157.8 g of methanol, 3.33 g of sodium triacetoxyborohydride, and 16 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 55°C, and keep the reaction warm for 2 h.

[0045] (2) Add 22 mmol of 2,3-dimethoxybenzyl chloride to the above reactor, adjust the pH to 8-9 with sodium hydroxide, heat and reflux for 18 hours, and distill under reduced pressure to obtain a viscous solid. Recrystallize with cyclohexane to obtain a solid, and dry it at 105°C overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0046] Example 6

[0047] (1) Add 20 mmol of 1-aza-18-crown ether-6, 144 g of methanol, 4.21 g of sodium triacetoxyborohydride, and 21 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 60°C, and keep the reaction warm for 2 h.

[0048] (2) 19 mmol of 2,3-dimethoxybenzyl chloride was added to the above reactor, the pH was adjusted to 8-9 with sodium hydroxide, and the mixture was heated under reflux for 42 h. A viscous solid was obtained by distillation under reduced pressure, and the solid was recrystallized with cyclohexane. The solid was dried at 105° C. overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0049] Example 7

[0050] (1) Add 20 mmol of 1-aza-18-crown ether-6, 125 g of methanol, 3.3 g of sodium cyanoborohydride, and 19 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 55 ° C, and keep the reaction for 4 hours.

[0051] (2) Add 20 mmol of 2,3-dimethoxybenzyl chloride to the above reactor, adjust the pH to 8-9 with sodium hydroxide, heat and reflux for 45 hours, and distill under reduced pressure to obtain a viscous solid. Recrystallize with cyclohexane to obtain a solid, and dry it at 105°C overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0052] Example 8

[0053] (1) Add 20 mmol of 1-aza-18-crown ether-6, 135 g of methanol, 3.4 g of sodium cyanoborohydride, and 20 mmol of sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, heat to 60°C, and keep the reaction warm for 3 hours.

[0054] (2) Add 21 mmol of 2,3-dimethoxybenzyl chloride to the above reactor, adjust the pH to 8-9 with sodium hydroxide, heat and reflux for 48 hours, and distill under reduced pressure to obtain a viscous solid. Recrystallize with cyclohexane to obtain a solid, and dry it at 105°C overnight to obtain the product high-temperature acidification corrosion inhibitor.

[0055] Example 9 Corrosion Rate Test

[0056] The static corrosion rate at normal pressure and the dynamic corrosion rate at high temperature and high pressure were determined with reference to the method in SY / T 5405-2019 “Test method and evaluation method for performance of corrosion inhibitors for acidification”. The different test parameters are shown in Tables 1 and 2, and the test results are shown in Table 3.

[0057] A comparative experiment was conducted using the acidizing corrosion inhibitor HJ-1 from Shandong Juxin New Materials Co., Ltd.

[0058] Table 1 Test conditions for static corrosion rate at normal pressure

[0059]

[0060] Table 2 High temperature and high pressure dynamic corrosion rate measurement conditions

[0061]

[0062] Table 3 Corrosion rate test results

[0063]

[0064] From Table 2 we can see that:

[0065] (1) When 5 wt% of corrosion inhibitor is added to 20 wt% hydrochloric acid solution at 180 °C, the corrosion rate is lower than 15 g / (m 2 ·h); while the corrosion rate of the acidified corrosion inhibitor HJ-1 of Shandong Juxin New Materials Co., Ltd. is 61g / (m 2 h), which is significantly higher than that of the present invention.

[0066] (2) When 6 wt% of corrosion inhibitor was added to 12 wt% hydrochloric acid + 3 wt% hydrofluoric acid solution at 180 °C, the corrosion rate was lower than 22 g / (m 2 ·h). The corrosion rate of the acidified corrosion inhibitor HJ-1 of Shandong Juxin New Materials Co., Ltd. is 66g / (m 2 h), which is significantly higher than that of the present invention.

[0067] The preferred embodiments of the present invention are described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the technical concept of the present invention, various simple modifications can be made to the technical solution of the present invention, and these simple modifications all fall within the scope of protection of the present invention.

[0068] It should also be noted that the various specific technical features described in the above specific embodiments can be combined in any appropriate manner without contradiction. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations.

[0069] In addition, the various embodiments of the present invention may be arbitrarily combined, and as long as they do not violate the concept of the present invention, they should also be regarded as the contents disclosed by the present invention.

Claims

1. A high temperature acidification corrosion inhibitor, characterized in that: The molecular structural formula of the acidifying corrosion inhibitor is as follows: 。 2. The method for preparing a high-temperature acidification corrosion inhibitor according to claim 1, characterized in that: The specific steps of the preparation method are as follows: (1) Add 1-aza-18-crown-6, methanol, reducing agent, and sodium benzaldehyde-2,4-disulfonate into the reactor in sequence, stir evenly, adjust the pH to 2-3 with hydrochloric acid, and heat and keep the reaction; (2) Add 2,3-dimethoxybenzyl chloride to the above reactor, adjust the pH to 8-9 with sodium hydroxide, heat to reflux, and distill under reduced pressure to obtain a viscous solid, which is recrystallized with cyclohexane to obtain a solid, and then dried at 105°C overnight to obtain the product high-temperature acidification corrosion inhibitor; Based on 1 mole of 1-aza-18-crown-6, the amounts of sodium benzaldehyde-2,4-disulfonate and 2,3-dimethoxybenzyl chloride are 0.8-1.2 and 0.8-1.2 mole parts, respectively.

3. The method for preparing a high-temperature acidification corrosion inhibitor according to claim 2, characterized in that: Based on 1 mole of 1-aza-18-crown-6, the amounts of sodium benzaldehyde-2,4-disulfonate and 2,3-dimethoxybenzyl chloride are 0.9-1.1 and 0.9-1.1 mole parts, respectively.

4. The method for preparing a high-temperature acidification corrosion inhibitor according to claim 2, characterized in that: The mass ratio of methanol to 1-aza-18-crown-6 in step (1) is 20-30:

1.

5. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 2, characterized in that: The reducing agent in step (1) is one of sodium borohydride, sodium triacetoxyborohydride and sodium cyanoborohydride.

6. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 5, characterized in that: The reducing agent is one of sodium triacetoxyborohydride and sodium cyanoborohydride.

7. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 2 or 5, characterized in that: The mass ratio of the reducing agent to 1-aza-18-crown-6 is 0.2-0.8:

1.

8. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 2, characterized in that: The heating and insulation reaction in step (1) is carried out at a temperature of 50-60°C and for a time of 1-4 hours.

9. The method for preparing a high-temperature acidizing corrosion inhibitor according to claim 2, characterized in that: The heating reflux time described in step (2) is 12-48h.

10. Use of the high-temperature acidizing corrosion inhibitor according to claim 1 in oil field acidizing fracturing.

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