A novel high-temperature resistant acid corrosion inhibitor and its preparation method

Abstract

A novel high-temperature resistant acid corrosion inhibitor preparation method includes the following steps: S1 Weigh a solvent and place it in a three-necked flask for later use. The solvent is one or a mixture of two of DMF, anhydrous ethanol, and glycerol. S2 Weigh benzaldehyde and cyclohexanone into the three-necked flask, seal and heat to 120°C, while simultaneously stirring and reacting for 3 hours. S3 Add a mixture of nonionic polyacrylamide, octadecylamine, and triamine citrate and react for 5 hours. After the reaction is complete, cool to room temperature. S4 Add one or a mixture of two of Tween 60 and Tween 80. The acid corrosion inhibitor prepared by this method exhibits good solubility and dispersibility at ultra-high temperatures of 140–200°C and does not exhibit coking or stratification. When applied to downhole equipment protection, it can improve the effect of oil and gas production enhancement and stimulation while slowing down the corrosion of downhole equipment.

Description

[Technical Field]

[0001] This invention belongs to the field of oilfield chemical technology, specifically relating to a high-temperature acidification corrosion inhibitor suitable for 140-200℃ and its preparation method. [Background Technology]

[0002] Energy utilization severely restricts economic construction and development. Conventional oil and gas resources can no longer meet people's energy needs, and the development of unconventional oil and gas resources such as low-permeability and tight reservoirs has become a new and important trend. Acidizing, as one of the main measures for enhancing production in low-porosity and low-permeability oil and gas reservoirs, can increase formation permeability and improve recovery rates. However, while acidizing brings higher production, it also increases the corrosion of downhole equipment in oil and gas wells. Especially as oil and gas extraction moves towards deeper and ultra-deep reservoirs, the ultra-high temperature and high pressure environment exacerbates the corrosion of downhole equipment by acid.

[0003] To prevent acid corrosion of downhole equipment under high temperature and high pressure environments, current methods include using acid corrosion inhibitors, upgraded materials, and surface coatings. Acid corrosion inhibitors, as a corrosion protection method for oil and gas wells, are widely used due to their economic efficiency, ease of operation, and significant effectiveness compared to other corrosion protection methods. After a long period of development, a wide variety of acid corrosion inhibitors have been developed, mainly Mannich bases and pyridine quaternary ammonium salts. However, when the temperature rises, the adsorption and temperature resistance of these inhibitors decrease significantly, especially above 140℃, where poor dissolution and dispersion, and easy coking and stratification may occur. Since the operating environment temperature of downhole equipment generally exceeds 140℃, existing acid corrosion inhibitors cannot provide effective corrosion protection for downhole equipment.

[0004] Therefore, it is necessary to develop an acid corrosion inhibitor suitable for use under ultra-high temperature conditions of 140-200℃ in order to improve the effect of oil and gas production enhancement and reduce the corrosion of downhole equipment. [Summary of the Invention]

[0005] To address the aforementioned problems, this invention provides a novel method for preparing a high-temperature acid corrosion inhibitor. The acid corrosion inhibitor prepared using this method exhibits excellent solubility and dispersibility at ultra-high temperatures of 140–200°C and does not exhibit coking or stratification. When applied to downhole equipment protection, it can improve the effect of oil and gas production enhancement and modification while mitigating corrosion of downhole equipment.

[0006] This invention is achieved through the following technical solution, providing a novel high-temperature acid corrosion inhibitor, which, by weight, comprises the following components:

[0007] The solvent comprises 2-5 parts, benzaldehyde 4 parts, cyclohexanone 2 parts, a mixture of nonionic polyacrylamide, octadecylamine, and triammonium citrate 1 part, and Tween 60 and / or Tween 80 0.5 parts. In this invention, the Tween 60 and Tween 80 are mixed in any proportion.

[0008] Specifically, the solvent is one or any two of DMF, anhydrous ethanol, and glycerol mixed in any proportion.

[0009] Specifically, in this invention, the selection of the molecular weight of the nonionic polyacrylamide is determined by the product's corrosion resistance. For the same product, when its operating temperature is 140-150℃, a nonionic polyacrylamide with a molecular weight of 600 is selected; when its operating temperature is greater than 150℃, a mixture of 2-5 nonionic polyacrylamides with molecular weights of 6-15 million is selected. In this case, the mixture must contain one low molecular weight nonionic polyacrylamide and one high molecular weight nonionic polyacrylamide, which are mixed in the same proportion, such as a 1:1 mixture of polyacrylamides with a molecular weight of 6 million and 15 million. In this way, the high molecular weight Mannich base groups in the final corrosion inhibitor are first adsorbed on the metal surface, and the low molecular weight Mannich base groups are later used to fill the unadsorbed areas of the high molecular weight groups, thereby forming a more comprehensive protective film.

[0010] Specifically, at 140-150℃, the content of the nonionic polyacrylamide is less than 0.4 parts, and the octadecylamine and triammonium citrate are mixed in a 4:1 ratio; at temperatures above 150℃, the content of the nonionic polyacrylamide is greater than 0.4 parts, and the octadecylamine and triammonium citrate are mixed in a 4:1 ratio.

[0011] This invention also provides a method for preparing a novel high-temperature resistant acid corrosion inhibitor, comprising the following steps:

[0012] S1 Weigh 100 grams of solvent and place it in a three-necked flask for later use. The solvent is one or a mixture of two of DMF, anhydrous ethanol, and glycerol in any ratio.

[0013] S2 Weigh 212.5 g of benzaldehyde and 98 g of cyclohexanone into a three-necked flask, seal and heat to 120°C, while stirring and reacting for 3 hours.

[0014] S3 was added to a mixture of 145 g nonionic polyacrylamide, 78 g octadecylamine, and 40 g triamine citrate and reacted for 5 h. After the reaction was completed, the mixture was cooled to room temperature.

[0015] Adding 31 grams of S4 to a mixture of one or two of Tween 60 and Tween 80, and stirring at room temperature for 10 minutes, will yield a new type of high-temperature resistant acid corrosion inhibitor.

[0016] Specifically, the synthetic molecular formula of the novel high-temperature acid-resistant corrosion inhibitor is as follows:

[0017]

[0018] Compared with existing technologies, this invention provides a novel method for preparing a high-temperature acid corrosion inhibitor. The acid corrosion inhibitor prepared by this method has the following beneficial effects:

[0019] 1. Existing high-temperature acid corrosion inhibitors are generally used in combination with agent A and agent B. Although they can achieve certain effects, they will cause problems such as precipitation and flocculation after mixing. This increases the difficulty of dosing and management, as well as the cost of the agent. The acid corrosion inhibitor provided in this case is a single agent, which solves the problem of using non-single agents, greatly reduces the difficulty of dosing and management, and has the characteristics of good agent stability, clear and no precipitation.

[0020] 2. The introduction of the macromolecular polymer polyacrylamide significantly increases the effective functional groups of the agent, thereby greatly improving the agent's temperature resistance and adsorption properties.

[0021] 3. Compared with pyridine-based acid corrosion inhibitors, which have an irritating odor and are carcinogenic, the acid corrosion inhibitor provided in this case has no irritating odor and is not carcinogenic.

[0022] 4. Conventional Mannich bases have relatively simple compositions. The acid corrosion inhibitor provided in this case introduces triammonium citrate, polyacrylamide, and octadecylamine, resulting in a greater variety of Mannich base functional groups. Furthermore, the molecular weights of the various Mannich bases differ, thus the prepared corrosion inhibitor exhibits a more prominent protective effect. This is because Mannich base groups of different molecular weights have different adsorption forces on the metal surface. Large molecular weights adsorb rapidly, while small molecular weights can fill the gaps on the unadsorbed metal surface. The maximum protective temperature can reach 240℃.

[0023] In summary, the acid corrosion inhibitor provided in this case introduces benzene rings and polyacrylamide macromolecules, solving the problems of poor adsorption and poor temperature resistance of traditional corrosion inhibitors. The benzene ring contains unsaturated bonds that can be adsorbed onto the metal surface. As the molecular weight increases, the temperature resistance of the corrosion inhibitor will improve, and the adsorption performance will become stronger. At the same time, this acid corrosion inhibitor does not introduce new difficult-to-treat substances, such as pyridine quaternary ammonium salts, which reduces the difficulty of subsequent water treatment. [Attached Image Description]

[0024] Figure 1 These are unprocessed test pieces;

[0025] Figure 2 These are test pieces treated with the acid corrosion inhibitor of this invention;

[0026] Figure 3The test pieces are treated with the existing Mannich base corrosion inhibitor. The two test pieces on the left show the appearance after the test at 200℃, and the two test pieces on the right show the appearance after the test at 90℃.

Detailed Implementation Methods

[0027] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0028] Example 1

[0029] 100 g of DMF was weighed and placed in a three-necked flask as a solvent. 212.5 g of benzaldehyde and 98 g of cyclohexanone were added to the flask. The mixture was sealed and heated to 120°C with stirring for 3 hours. Then, 145 g of a mixture of nonionic polyacrylamide (8 million and 14 million molecular weights, prepared in a 1:1 ratio), 78 g of octadecylamine, and 40 g of triammonium citrate were added and reacted for 5 hours. After the reaction was complete, the mixture was cooled to room temperature, and 31 g of Tween 60 was added and stirred for 15 minutes. The performance of the high-temperature acid corrosion inhibitor prepared in this example was evaluated using a high-temperature, high-pressure corrosion rate tester according to the requirements of standard SY / T 5405-2019.

[0030] Example 2

[0031] A mixture of 100 g DMF and anhydrous ethanol was placed in a three-necked flask as a solvent. 212.5 g benzaldehyde and 98 g cyclohexanone were added to the flask. The mixture was sealed and heated to 120°C with stirring for 3 hours. Then, 145 g of a mixture of nonionic polyacrylamide (6 million and 15 million molecular weights) in a 1:1 ratio, 78 g octadecylamine, and 40 g triammonium citrate were added and reacted for 5 hours. After the reaction was complete, the mixture was cooled to room temperature, and 15.5 g each of Tween 60 and Tween 80 were added and stirred for 15 minutes. The performance of the high-temperature acid corrosion inhibitor prepared in this example was evaluated using a high-temperature, high-pressure corrosion rate tester according to the requirements of standard SY / T 5405-2019.

[0032] Comparative Example

[0033] The performance of the existing Mannich base corrosion inhibitor was evaluated on a high-temperature acidification corrosion inhibitor using a high-temperature and high-pressure corrosion rate tester, in accordance with the requirements of standard SY / T 5405-2019.

[0034] After testing, it was found that:

[0035] Experiments were conducted using the acid corrosion inhibitor prepared in Example 1. At an experimental temperature of 140°C, the corrosion rate of the test piece with 20% hydrochloric acid was 11.9 g / cm·h; at an experimental temperature of 200°C, the corrosion rate of the test piece with 20% hydrochloric acid was 45.6 g / cm·h, which meets and is far less than the requirements in standard SY / T 5405. Therefore, it is evident that the acid corrosion inhibitor prepared in Example 2, when applied to the test piece, exhibits a low corrosion rate and excellent protective effect. Thus, this acid corrosion inhibitor can be applied to the protection of downhole equipment in high-temperature environments.

[0036] The acid corrosion inhibitor prepared in Example 2 was used in experiments. At an experimental temperature of 140℃, the corrosion rate of the test piece with 20% hydrochloric acid was 10.6 g / cm·h, and at an experimental temperature of 200℃, the corrosion rate was 35.6 g / cm·h. These values ​​meet and are significantly lower than the requirements of standard SY / T 5405, and are superior to the acid corrosion inhibitor prepared in Example 1. Therefore, the acid corrosion inhibitor prepared in Example 2, when applied to the test piece, exhibits a low corrosion rate and excellent protective effect, while also... Figure 1 and Figure 2 It can be seen that the acid corrosion inhibitor prepared in this embodiment provides good protection for the test piece even under high temperature conditions. Therefore, this acid corrosion inhibitor can be used to protect downhole equipment in high temperature environments.

[0037] Experiments were conducted using the Mannich base corrosion inhibitor needle from the example. At an experimental temperature of 90℃, the corrosion rate of the sample with 20% hydrochloric acid was 2.1 g / cm·h, and at 200℃, the corrosion rate was 205.6 g / cm·h. This demonstrates that its protective effect is inferior to the acid corrosion inhibitor prepared in this invention. Figure 3 This is a diagram illustrating the protective effect of the corrosion inhibitor on the product. Figure 3 It can be seen that the existing acid corrosion inhibitors have a decent protective effect at a temperature of 90℃, but the protective effect is worse than that of the acid corrosion inhibitors prepared in this case. When the temperature reaches 200℃, the test piece is severely corroded. Therefore, the existing acid corrosion inhibitors do not have an ideal protective effect on downhole equipment in high-temperature environments.

Claims

1. A novel high-temperature resistant acid corrosion inhibitor, characterized in that, Based on parts by weight, it includes the following components: The novel high-temperature acid corrosion inhibitor is prepared by the following method: 2-5 parts solvent, 4 parts benzaldehyde, 2 parts cyclohexanone, 1 part a mixture of nonionic polyacrylamide, octadecylamine, and triammonium citrate, and 0.5 parts Tween 60 and / or Tween 80. S1 Weigh the solvent and place it in a three-necked flask for later use. The solvent is one or a mixture of two of DMF, anhydrous ethanol, and glycerol in any ratio. S2 Weigh benzaldehyde and cyclohexanone into a three-necked flask, seal and heat to 120°C, while stirring and reacting for 3 hours. S3 was added to a mixture of nonionic polyacrylamide, octadecylamine, and triamine citrate and reacted for 5 hours. After the reaction was completed, the mixture was cooled to room temperature. Adding S4 to one or a mixture of two of Tween 60 and Tween 80, and stirring at room temperature for 10 minutes, will yield a new type of high-temperature resistant acid corrosion inhibitor.

2. The novel high-temperature acid corrosion inhibitor according to claim 1, characterized in that, The solvent is one or a mixture of any two of DMF, anhydrous ethanol, and glycerol.

3. The novel high-temperature acid corrosion inhibitor according to claim 1, characterized in that, When the operating temperature of the novel high-temperature resistant acid corrosion inhibitor is 140-150℃, the molecular weight of the nonionic polyacrylamide is 6 million; when the operating temperature of the novel high-temperature resistant acid corrosion inhibitor is greater than 150℃, the nonionic polyacrylamide is a mixture of 2-5 types with molecular weights of 6-15 million, and the mixture is composed of low molecular weight nonionic polyacrylamide and high molecular weight nonionic polyacrylamide in equal proportions.

4. The novel high-temperature acid corrosion inhibitor according to claim 1, characterized in that, When the operating temperature of the novel high-temperature resistant acid corrosion inhibitor is 140-150℃, the content of nonionic polyacrylamide is less than 0.4 parts, and octadecylamine and triammonium citrate are mixed in a 4:1 ratio; when the operating temperature of the novel high-temperature resistant acid corrosion inhibitor is greater than 150℃, the content of nonionic polyacrylamide is greater than 0.4 parts, and octadecylamine and triammonium citrate are mixed in a 4:1 ratio.

5. The preparation method of a novel high-temperature acid-resistant corrosion inhibitor according to claim 1, characterized in that, The reaction equation for the preparation method of the novel high-temperature acid-resistant corrosion inhibitor is as follows:

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