Corrosion inhibitor for carbon dioxide corrosion and preparation method thereof

Abstract

The invention relates to the field of oil and gas exploitation, in particular to a corrosion inhibitor for carbon dioxide corrosion and a preparation method thereof. The corrosion inhibitor for carbon dioxide corrosion comprises the following components: foots, sodium hydroxide, a paper pulp by-product, sulfuric acid, m-phenylenediamine, rosin amine, diethylenetriamine and EDTMP, and the paper pulp by-product is a by-product obtained by using wood as a raw material and preparing paper pulp through a sulfate method. The corrosion inhibitor for carbon dioxide corrosion not only is low in cost, but also is low in corrosion rate.

Description

TECHNICAL FIELD

[0001] The application relates to the field of oil and gas exploitation, in particular to a carbon dioxide corrosion inhibitor and a preparation method thereof. BACKGROUND

[0002] CCUS (Carbon Capture, Utilization and Storage) technology is an important technical means for addressing global climate change at present, and generally includes three directions of carbon capture, carbon utilization and carbon storage. Specifically, carbon capture refers to separating carbon dioxide emitted by industrial production (such as power plants, steel plants, etc.) from waste gas through chemical or physical methods; carbon utilization refers to resource utilization of captured carbon dioxide, for example, for production of chemicals, enhanced oil recovery, production of carbonated beverages, etc.; carbon storage refers to injecting carbon dioxide into deep geological structures in the ground, such as depleted oil and gas fields, deep saline aquifers, etc., so as to be isolated from the atmosphere for a long time. CCUS technology helps to reduce carbon dioxide emissions in the atmosphere, and has important significance for achieving global greenhouse gas emission reduction targets and mitigating climate change.

[0003] The utilization of carbon dioxide to improve recovery efficiency is a breakthrough for oilfields to realize green and low-carbon transformation. However, due to the high corrosiveness of carbon dioxide, it can cause casing and production string leakage and damage, and in severe cases, casing failure, carbon dioxide leakage to the surface, which directly threatens the safety of the entire injection well. In the process of carbon dioxide flooding, carbon dioxide huff and puff, and subsequent expansion of CCUS application, carbon dioxide in the downhole humid environment, especially under high pressure and certain temperature, will cause serious corrosion problems to the injection well and production well casing and pump, affecting normal production. The simplest anticorrosion measure for injection wells and production wells is to add an inhibitor to the production well to achieve the purpose of corrosion protection of the production well.

[0004] An inhibitor is a chemical substance that can prevent or slow down corrosion when it exists in the environment (usually a corrosive medium) in an appropriate concentration and form. Inhibitors are widely used in many fields, such as petroleum and chemical industry, metal processing, water treatment, etc. Different types of inhibitors are suitable for different corrosion environments and metal materials. Common inhibitors include inorganic inhibitors (such as chromate, phosphate, etc.), organic inhibitors (such as amines, aldehydes, etc.). Traditional inhibitors often cannot completely adapt to new situations in carbon dioxide corrosion. In recent years, many researchers have devoted themselves to the research of inhibitors for carbon dioxide corrosion, but existing carbon dioxide inhibitors still have problems such as high price, unsatisfactory corrosion inhibition effect, and non-environmental application. SUMMARY

[0005] In view of the above, the present application provides a low-cost and effective corrosion inhibitor for carbon dioxide corrosion, and a preparation method of the corrosion inhibitor for carbon dioxide corrosion.

[0006] To solve at least one of the above technical problems, the present application adopts the following technical solutions: According to the present application, a corrosion inhibitor for carbon dioxide corrosion is provided, comprising the following components: oil foot, sodium hydroxide, paper pulp by-product, sulfuric acid, m-phenylenediamine, rosin amine, diethylene triamine and EDTMP, wherein the paper pulp by-product is a by-product obtained by using wood as raw material to produce paper pulp by the kraft process.

[0007] According to an embodiment of the present application, the ratio of each component of the corrosion inhibitor is as follows: oil foot: 80-100 parts by weight; sodium hydroxide: 40-45 parts by weight; paper pulp by-product: 35-45 parts by weight; sulfuric acid: 80-100 parts by weight; m-phenylenediamine: 15-25 parts by weight; rosin amine: 10-15 parts by weight; diethylene triamine: 10-15 parts by weight; and EDTMP: 0.5-1.5 parts by weight.

[0008] According to an embodiment of the present application, the ratio of each component of the corrosion inhibitor is as follows: Oil foot: 90 parts by weight; Sodium hydroxide: 40.5 parts by weight; Paper pulp by-product: 40.5 parts by weight; Sulfuric acid: 90 parts by weight; M-phenylenediamine: 22.5 parts by weight; Rosin amine: 13.5 parts by weight; Diethylene triamine: 13.5 parts by weight; EDTMP: 1.35 parts by weight.

[0009] According to an embodiment of the present application, the sodium salt of fatty acid accounts for 20-40% of the oil foot in terms of weight percentage.

[0010] According to an embodiment of the present application, the carboxylate accounts for 10-30% of the paper pulp by-product in terms of weight percentage.

[0011] According to the application, a preparation method of a carbon dioxide corrosion inhibitor is provided, comprising the following steps: S1, heating a reaction kettle to 80-90 DEG C, then adding oil feet into the reaction kettle, starting stirring, and adding sodium hydroxide while stirring; S2, heating the reaction kettle to 90-95 DEG C, adding paper pulp by-product while stirring, then adding concentrated sulfuric acid, and obtaining a reaction product after 1.8-2.2 hours of reaction, wherein the paper pulp by-product is a by-product obtained by using wood as raw material to produce paper pulp by the kraft process; S3, introducing the reaction product from the reaction kettle into a high-temperature centrifuge for separation, and taking the upper liquid; S4, adding the upper liquid into the reaction kettle, heating the reaction kettle to 55-65 DEG C, and adding m-phenylenediamine, rosin amine, diethylene triamine and EDTMP in sequence while continuously stirring; S5, after the addition is completed, heating to 80-90 DEG C, continuously stirring for 40-45 minutes, and obtaining a mixture; S6, heating the temperature of the reaction kettle to 175-185 DEG C, separating water in the mixture, and obtaining the corrosion inhibitor.

[0012] According to an embodiment of the application, the proportion of each component of the corrosion inhibitor is as follows: oil feet: 80-100 parts by weight; sodium hydroxide: 40-45 parts by weight; paper pulp by-product: 35-45 parts by weight; sulfuric acid: 80-100 parts by weight; m-phenylenediamine: 15-25 parts by weight; rosin amine: 10-15 parts by weight; diethylene triamine: 10-15 parts by weight; and EDTMP: 0.5-1.5 parts by weight.

[0013] According to an embodiment of the application, in steps S1, S2, S4, S5 and S6, the heating rate is controlled to be 4-5 DEG C / min.

[0014] According to an embodiment of the application, in step S1, after adding sodium hydroxide, continue to stir for 1.8-2.2 hours.

[0015] According to an embodiment of the application, in step S2, the concentrated sulfuric acid is added into the reaction kettle in multiple times slowly.

[0016] According to an embodiment of the application, in step S3, the centrifuge is controlled to centrifuge at a speed of 1500-2000 r / min for 0.5-1.5 hours.

[0017] According to an embodiment of the application, in step S6, a reflux water trap is used to separate water in the mixture, and the reflux water trap is maintained for 2-2.5 hours.

[0018] By adopting the above technical solution, the application has at least one of the following advantages compared with the prior art: 1. The carbon dioxide corrosion inhibitor according to the present application uses oil foot and paper pulp by-product as components, not only realizes the secondary use of industrial by-products, but also avoids the use of expensive raw materials, and effectively reduces the production cost; 2. The carbon dioxide corrosion inhibitor according to the present application has low corrosion rate and good corrosion inhibition effect on metals in the carbon dioxide injection environment through simulation of the field working condition; 3. The components of the carbon dioxide corrosion inhibitor according to the present application are non-toxic and easy to decompose, and will not cause environmental pollution; 4. The preparation method of the carbon dioxide corrosion inhibitor according to the present application is simple in steps and easy to operate, and is suitable for popularization and use in the industry. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiment or prior art description. Obviously, the drawings in the following description only some embodiments of the present application, and for those skilled in the art, without creative labor, other embodiments can also be obtained from these drawings.

[0020] Figure 1 The flow chart of the carbon dioxide corrosion inhibitor and its preparation method provided by an embodiment of the present application. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical scheme and advantages of the present application more clear, the following will be further described in detail by combining with specific embodiments and referring to the drawings.

[0022] It should be understood that the embodiments of the present application shown in the exemplary embodiments are only illustrative. Although only a few embodiments are described in detail in the present application, those skilled in the art can easily appreciate that various modifications are possible without departing from the teachings of the present application subject matter. Accordingly, all such modifications should be included in the scope of the present application. Other substitutions, modifications, changes and omissions can be made to the design, operating conditions and parameters of the following exemplary embodiments without departing from the spirit of the present application.

[0023] According to one aspect of the present application, a carbon dioxide corrosion inhibitor is provided, which generally comprises the following components: oil foot, sodium hydroxide, paper pulp by-product, sulfuric acid, m-phenylenediamine, rosin amine, diethylene triamine and EDTMP. The above components are all commercially available industrial products, and any commercially available product meeting the corresponding quality standards can be used in the present application and achieve the purpose of the present application.

[0024] Oil foot (Lecithin gum) is a by-product of the hydration degumming process in oil refining, usually refers to the thick material precipitated at the bottom of the container after oil refining. The main components of oil foot can include: phospholipids, free fatty acids, pigments and other impurities such as proteins, carbohydrates, minerals, etc. In some cases, oil foot can be used as a food additive in food processing, edible oil can be extracted from it through a specific process, or after further processing and treatment, it can be used to produce feed, fertilizer, biodiesel and other products. With oil foot as a component, it will not cause environmental pollution. In the present invention, oil foot is saponified with alkali to produce fatty acid sodium salt, and then the fatty acid sodium salt is acidified into fatty acid with strong acid, which can effectively control the corrosion rate of carbon dioxide. In the embodiment of the present invention, the content of fatty acid sodium salt in oil foot is 20-40% by weight, preferably 30%.

[0025] Paper pulp by-product is a by-product of paper pulp production. Due to its low purity and high fatty acid content, it was previously a waste that was difficult to dispose of. In the present invention, the alkali of the paper pulp by-product can be further reacted with oil foot, and then organic acid can be produced by using sulfuric acid. Specifically, the paper pulp by-product contains carboxylate, lignin and water, and the main use is the carboxylate inside. After adding sulfuric acid, organic acids are produced. The content of carboxylate can be 10-30% by weight, preferably 20%. In the embodiment of the present invention, the by-product obtained by using pine as raw material to produce paper pulp by the sulfite process can be selected, and its components mainly include: black liquor, containing a large amount of lignin degradation products, dissolved part of hemicellulose, various sodium salts (such as sodium sulfate, sodium carbonate, etc.), a small amount of cellulose and residual pulping chemicals, and some turpentine components such as abietic acid, fatty acid, etc.; tall oil, mainly composed of fatty acids, resin acids and unsaponifiable matter; turpentine oil: a volatile mixture of terpenes, including α-pinene, β-pinene and other components; dissolved sugar substances: such as xylose, mannose and other hemicellulose hydrolysates. Among them, the turpentine components such as abietic acid and fatty acid can be used to generate organic acid.

[0026] M-phenylenediamine, also known as 1,3-phenylenediamine, is an organic compound with the chemical formula C6H8N2. It is a white needle-like crystal at room temperature, soluble in water and organic solvents such as ethanol, acetone, etc. M-phenylenediamine can be widely used in the manufacture of disperse dyes, reactive dyes, direct dyes and cement accelerators.

[0027] Abietamine is a light yellow viscous oily liquid with a pungent ammonia smell, slightly soluble in boiling water, easily soluble in alcohol, ether, hydrocarbon and most organic solvents. It can be used as an additive for lubricants, asphalt emulsifier, wood preservative, corrosion inhibitor, bactericide and algicide in industrial water treatment, and sludge stripping agent in sewage system.

[0028] Diethylenetriamine, chemical formula C4H13N3, is a light yellow liquid, soluble in water, ethanol, acetone, mainly used as a solvent and organic synthesis intermediates.

[0029] EDTMPA, also known as ethylenediamine tetramethylene phosphonic acid, molecular formula C6H20N2O12P4, has strong chelating properties, can form stable complex with iron ions, copper, aluminum, zinc, calcium, magnesium and other ions. It still has good scale inhibition effect at 200℃. It is commonly used as a scale and corrosion inhibitor for industrial circulating cooling water, boiler water, circulating water of power plant. It can also be used as a complexing agent for cyanide-free electroplating.

[0030] In the embodiment of the present application, the ratio of each component of the corrosion inhibitor is preferably: 80-100 parts by weight of oil foot; 40-45 parts by weight of sodium hydroxide; 35-45 parts by weight of paper pulp by-product; 80-100 parts by weight of sulfuric acid; 15-25 parts by weight of m-phenylenediamine; 10-15 parts by weight of rosin amine; 10-15 parts by weight of diethylenetriamine; 0.5-1.5 parts by weight of EDTMP.

[0031] According to one aspect of the present application, a method for preparing a corrosion inhibitor for carbon dioxide corrosion is provided. As shown in Figure 1 the method generally comprises the following steps: S1, the reaction kettle is heated to 80-90℃, then the oil foot is added to the reaction kettle, and the stirring is started, and the sodium hydroxide is added while stirring; S2, the reaction kettle is heated to 90-95℃, the paper pulp by-product is added while stirring, then the concentrated sulfuric acid is added, and the reaction product is obtained after 1.8-2.2h of reaction, wherein the paper pulp by-product is a by-product obtained by using pine as raw material to produce paper pulp by the sulfite process; S3, the reaction product is introduced into a high-temperature centrifuge for separation, and the upper liquid is taken; S4, the upper liquid is added to the reaction kettle, the reaction kettle is heated to 55-65℃, and the m-phenylenediamine, rosin amine, diethylenetriamine and EDTMP are added in turn while stirring; S5, after the addition is completed, the temperature is raised to 80-90℃, and the stirring is continued for 40-45min to obtain a mixture; S6, the temperature of the reaction kettle is raised to 175-185℃, the water in the mixture is separated, and the corrosion inhibitor is obtained.

[0032] In the embodiment of the present application, the ratio of each component of the corrosion inhibitor is preferably: 80-100 parts by weight of oil foot; 40-45 parts by weight of sodium hydroxide; 35-45 parts by weight of paper pulp by-product; 80-100 parts by weight of sulfuric acid; 15-25 parts by weight of m-phenylenediamine; 10-15 parts by weight of rosin amine; 10-15 parts by weight of diethylenetriamine; 0.5-1.5 parts by weight of EDTMP.

[0033] In step S1, the reactor can be heated to 80-90°C at a heating rate of 4-5°C / min, and after the addition of sodium hydroxide, continue to stir for 1.8-2.2h to fully mix the oil foot and sodium hydroxide.

[0034] In step S2, the reactor can be heated to 90-95°C at a heating rate of 4-5°C / min. Concentrated sulfuric acid is added slowly, preferably in multiple times. In the examples of the present application, the concentrated sulfuric acid can be added in 4 times. Those skilled in the art can adjust the number of times and the addition rate of concentrated sulfuric acid according to the actual working conditions.

[0035] In step S3, the centrifuge can be controlled at a speed of 1500-2000r / min for 0.5-1.5h to fully separate the solid and liquid. In the examples of the present application, it is preferred to separate at a speed of 2000r / min for 1h.

[0036] In steps S4 and S5, the heating rate is preferably controlled at 4-5°C / min.

[0037] In step S6, the water in the mixture is separated using a reflux water trap. The reflux water trap is an experimental device that separates the water generated by the reaction from the organic solvent, so that the water remains in the water trap, and the organic solvent returns to the reaction system. In the examples of the present application, the reflux water trap is preferably maintained for 2-2.5h to ensure that all the water is separated out.

[0038] The present application will be further described below in conjunction with specific examples and comparative examples.

[0039] Example 1 In the examples of the present application, the ratio of the components of the corrosion inhibitor is: 100 parts by weight of oil foot; 45 parts by weight of sodium hydroxide; 45 parts by weight of paper pulp by-product; 100 parts by weight of sulfuric acid; 25 parts by weight of m-phenylenediamine; 15 parts by weight of rosin amine; 15 parts by weight of diethylene triamine; 1.5 parts by weight of EDTMP. Among them, the sodium salt of fatty acid in the oil foot accounts for 30%; the paper pulp by-product is a by-product obtained by sulfite pulping of pine as raw material, and the carboxylate accounts for 40%.

[0040] The synthesis of 1 ton of corrosion inhibitor comprises the following steps: Step S1, the reactor is heated to 80°C at a heating rate of 5°C / min, then 288.6kg of oil foot is added to the reaction vessel, and stirring is started, 130kg of sodium hydroxide is added while stirring, and then stirring is continued for 2h; Step S2, the reaction kettle is heated to 90℃, the heating rate is 4℃ / min, 130kg of paper pulp by-product is added while stirring, then 288.6kg of concentrated sulfuric acid is slowly added in 4 times, the reaction product is obtained after 2h of reaction; Step S3, the reaction product is introduced into a high-temperature centrifuge from the reaction kettle, and centrifugation is performed at 2000r / min for 1h, and the upper liquid is taken; Step S4, the obtained upper liquid is added into the reaction kettle, the reaction kettle is heated to 60℃, the heating rate is 5℃ / min, 72kg of m-phenylenediamine, 43.3kg of rosin amine, 43.3kg of diethylenetriamine and 4.3kg of EDTMP are added in turn and dropwise under continuous stirring; Step S5, after the dropwise addition is completed, the temperature is increased to 80℃ at a heating rate of 4℃ / min, and the stirring is continued for 45min to obtain a mixture; Step S6, the temperature of the reaction kettle is increased to 180℃ at a heating rate of 5℃ / min, and the water is separated from the water separator for 2h to obtain the corrosion inhibitor.

[0041] Example 2 In the embodiment of the present application, the ratio of the components of the corrosion inhibitor is: 80 parts by weight of oil foot; 40 parts by weight of sodium hydroxide; 35 parts by weight of paper pulp by-product; 80 parts by weight of sulfuric acid; 15 parts by weight of m-phenylenediamine; 10 parts by weight of rosin amine; 10 parts by weight of diethylenetriamine; and 0.5 parts by weight of EDTMP. Among them, the sodium salt of fatty acid in the oil foot accounts for 20%; the paper pulp by-product is a by-product obtained by sulfite pulping of pine as raw material, and the carboxylate accounts for 10%.

[0042] Synthesizing 1 ton of corrosion inhibitor specifically includes the following steps: Step S1, the reaction kettle is heated to 90℃, the heating rate is 4℃ / min, then 295.7kg of oil foot is added into the reaction vessel, and the stirring is started, 147.9kg of sodium hydroxide is added while stirring, and then the stirring is continued for 2.2h; Step S2, the reaction kettle is heated to 95℃, the heating rate is 5℃ / min, 130kg of paper pulp by-product is added while stirring, then 296kg of concentrated sulfuric acid is slowly added in 3 times, the reaction product is obtained after 1.8h of reaction; Step S3, the reaction product is introduced into a high-temperature centrifuge from the reaction kettle, and centrifugation is performed at 1500r / min for 1.5h, and the upper liquid is taken; Step S4, the obtained upper liquid is added into the reaction kettle, the reaction kettle is heated to 55℃, the heating rate is 5℃ / min, 55.5kg of m-phenylenediamine, 37kg of rosin amine, 37kg of diethylenetriamine and 1.8kg of EDTMP are added in turn and dropwise under continuous stirring; Step S5, after the drop is finished, the temperature is raised to 85℃ at a rate of 5℃ / min, and stirring is continued for 40min to obtain a mixture; Step S6, the temperature of the reactor is raised to 185℃ at a rate of 4℃ / min, and water is separated from the water separator for 2.3h to obtain the corrosion inhibitor.

[0043] Example 3 In the embodiment of the present application, the ratio of the components of the corrosion inhibitor is: 90 parts by weight of oil foot; 43 parts by weight of sodium hydroxide; 40 parts by weight of paper pulp by-product; 85 parts by weight of sulfuric acid; 20 parts by weight of m-phenylenediamine; 12 parts by weight of rosin amine; 13 parts by weight of diethylenetriamine; and 1 part by weight of EDTMP. Among them, the sodium salt of fatty acid in the oil foot accounts for 40%; the paper pulp by-product is a by-product obtained by using pine as raw material to produce paper pulp by the sulfite process, and the carboxylate accounts for 30%.

[0044] The synthesis of 1 ton of corrosion inhibitor specifically includes the following steps: Step S1, the temperature of the reactor is raised to 85℃ at a rate of 5℃ / min, then 296kg of oil foot is added to the reaction container, and stirring is started, while 141.4kg of sodium hydroxide is added, and then stirring is continued for 1.8h; Step S2, the temperature of the reactor is raised to 90℃ at a rate of 4℃ / min, while stirring, 131.6kg of paper pulp by-product is added, then 280kg of concentrated sulfuric acid is slowly added in 5 times, and after 2.2h of reaction, the reaction product is obtained; Step S3, the above reaction product is introduced into a high-temperature centrifuge from the reactor, and centrifuged at 2000r / min for 0.5h, and the upper liquid is taken; Step S4, the obtained upper liquid is added to the reactor, the temperature of the reactor is raised to 65℃ at a rate of 4℃ / min, and 65.8kg of m-phenylenediamine, 39.5kg of rosin amine, 42.7kg of diethylenetriamine, and 3.3kg of EDTMP are added dropwise in turn under continuous stirring; Step S5, after the drop is finished, the temperature is raised to 85℃ at a rate of 5℃ / min, and stirring is continued for 40min to obtain a mixture; Step S6, the temperature of the reactor is raised to 175℃ at a rate of 5℃ / min, and water is separated from the water separator for 2.5h to obtain the corrosion inhibitor.

[0045] According to another aspect of the present application, indoor evaluation experiments are conducted in the laboratory to measure the performance of the corrosion inhibitor prepared according to the above method under simulated field conditions.

[0046] Before the experiment, the corrosion plates were wiped clean with filter paper and then placed in a container with petroleum ether or acetone with a boiling range of 60~90℃. After removing the grease from the surface of the plates with degreased cotton, they were soaked in anhydrous ethanol for about 5 minutes to further degrease and dehydrate. After removing the plates, they were placed on filter paper, dried with cold air, wrapped in filter paper, and stored in a desiccator. After 1 hour, the size and weight were measured and weighed to an accuracy of 0.1 mg.

[0047] Simulated water was taken from the reactor according to its volume and placed inside. Nitrogen gas was first introduced into the simulated water for 0.5 hours to remove oxygen. Then, treated N80 corrosion strips were attached, and the reactor lid was sealed. The carbon dioxide pressure was set according to the actual field conditions, and the reactor was kept at a constant temperature to the actual field temperature for a static corrosion evaluation experiment. The experiment lasted for 72 hours. Three parallel experiments were conducted for each group, and the average value of the parallel experiments was taken as the measurement result.

[0048] After removing the trays that have reached the experimental cycle, observe and record the surface corrosion state and the adhesion of corrosion products. Immediately rinse off the experimental medium with clean water and dry the trays with filter paper. Place the trays in a container of petroleum ether or acetone with a boiling range of 60~90℃, gently wipe with degreased cotton, and then soak in anhydrous ethanol for 5 minutes for further degreasing and dehydration. Remove the trays and soak them in the acid cleaning solution prepared according to Appendix A of SY / T5273-2014 standard for 5 minutes, while gently wiping off the corrosion products on the surface of the trays with a small amount of degreased cotton using tweezers. Remove the trays from the cleaning solution, rinse off the residual acid on the surface with tap water, and immediately immerse the trays in a sodium hydroxide solution (60g / L) for 30 seconds, then rinse with tap water, and then soak in anhydrous ethanol for about 5 minutes, washing and dehydrating twice. Remove the tablets and place them on filter paper. Dry them with cold air, then wrap the tablets with filter paper and store them in a desiccator. Weigh them after 1 hour, accurate to 0.1 mg.

[0049] The corrosion rate is calculated using the following formula:

[0050] In the formula: r corr — Uniform corrosion rate, mm / a; m — Mass of the coated sample before the test, g; m t — Mass of the hanging strip after the test, g; S1 — Total area of ​​the hanging strip, cm² 2 ρ—Density of the padding material, g / cm³ 3 t——test time, h.

[0051] The test results are shown in Table 1: Table 1. Test results of corrosion inhibitor performance

[0052] The comparative example inhibitor uses a conventional inhibitor currently commonly used, and the main component comprises an imidazole phosphorus derivative. The effect of the inhibitor of the present application is evaluated through indoor experiments, and the metal has good corrosion inhibition effect under the carbon dioxide injection environment. The indoor corrosion rate determination simulation experiment is set to have a drug concentration of 100 mg / L, a corrosion reaction time of 72 h, and after adding the inhibitor prepared by the present application examples 1-3, the corrosion rate is 0.069-0.071 mm / a, which is significantly lower than that of the conventional inhibitor.

[0053] In the oil production well, the inhibitor is continuously added to the oil jacket annulus by using a dosing pump, the dosing concentration can be 50 mg / L-150 mg / L, and is mixed with the oil well production fluid to achieve the purpose of corrosion protection. Alternatively, the person skilled in the art can reasonably adjust the dosing concentration according to the actual working condition. In the carbon dioxide injection well, the inhibitor is prepared into a casing protection fluid, the casing protection fluid fills the entire wellbore from the oil jacket annulus, and then the casing protection fluid is sealed in the oil jacket annulus by using a packer to achieve the purpose of long-term protection of the casing.

[0054] The technical features of the above examples can be combined arbitrarily, and in order to make the description simple, all possible combinations of the technical features in the above examples are not described, however, as long as the combination of the technical features does not exist contradictory, it should be considered as the scope of the present application.

[0055] The above examples only express several embodiments of the present application, and the description is more specific and detailed, but it should not be understood as limiting the scope of the patent. It should be pointed out that for ordinary skilled in the art, without departing from the concept of the present application, a number of modifications and improvements can be made, which are within the scope of the present application. Therefore, the scope of the patent of the present application should be subject to the appended claims.

Claims

1. A corrosion inhibitor for carbon dioxide corrosion, characterized by comprising: The corrosion inhibitor comprises the following components: oil foot, sodium hydroxide, paper pulp by-product, sulfuric acid, m-phenylenediamine, rosin amine, diethylene triamine and EDTMP, wherein the paper pulp by-product is a by-product obtained by kraft pulping of wood.

2. The carbon dioxide corrosion inhibitor according to claim 1, characterized in that, The proportion of each component of the corrosion inhibitor is as follows: Oil foot: 80-100 parts by weight; Sodium hydroxide: 40-45 parts by weight; Paper pulp by-product: 35-45 parts by weight; Sulfuric acid: 80-100 parts by weight; M-phenylenediamine: 15-25 parts by weight; Rosin amine: 10-15 parts by weight; Diethylene triamine: 10-15 parts by weight; EDTMP: 0.5-1.5 parts by weight.

3. The carbon dioxide corrosion inhibitor according to claim 2, characterized in that, The proportion of each component of the corrosion inhibitor is as follows: Oil foot: 90 parts by weight; Sodium hydroxide: 40.5 parts by weight; Paper pulp by-product: 40.5 parts by weight; Sulfuric acid: 90 parts by weight; M-phenylenediamine: 22.5 parts by weight; Rosin amine: 13.5 parts by weight; Diethylene triamine: 13.5 parts by weight; EDTMP: 1.35 parts by weight.

4. The carbon dioxide corrosion inhibitor according to claim 2, characterized in that, The proportion of sodium salt of fatty acid in the oil foot is 20-40% by weight.

5. The carbon dioxide corrosion inhibitor according to claim 2, characterized in that, The proportion of carboxylate in the paper pulp by-product is 10-30% by weight.

6. A method for producing a carbon dioxide corrosion inhibitor, characterized by, The method comprises the following steps: S1, the reaction kettle is heated to 80-90℃, then the oil foot is added into the reaction kettle, and stirring is started, and sodium hydroxide is added while stirring; S2, the reaction kettle is heated to 90-95℃, the paper pulp by-product is added while stirring, then concentrated sulfuric acid is added, and the reaction product is obtained after 1.8-2.2h of reaction, wherein the paper pulp by-product is a by-product obtained by kraft pulping of wood; S3, the reaction product is introduced into a high-temperature centrifuge from the reaction kettle for separation, and the upper liquid is taken; S4, the upper liquid is added into the reaction kettle, the reaction kettle is heated to 55-65℃, and m-phenylenediamine, rosin amine, diethylene triamine and EDTMP are added in sequence while stirring; S5, after the addition is completed, the temperature is raised to 80-90℃, and stirring is continued for 40-45min to obtain a mixture; S6, the temperature of the reaction kettle is raised to 175-185℃, and the water in the mixture is separated to obtain the corrosion inhibitor.

7. The method for preparing the carbon dioxide corrosion inhibitor according to claim 6, characterized in that, The proportion of each component of the corrosion inhibitor is as follows: Oil foot: 80-100 parts by weight; Sodium hydroxide: 40-45 parts by weight; Paper pulp by-product: 35-45 parts by weight; Sulfuric acid: 80-100 parts by weight; M-phenylenediamine: 15-25 parts by weight; Rosin amine: 10-15 parts by weight; Diethylene triamine: 10-15 parts by weight; EDTMP: 0.5-1.5 parts by weight.

8. The method for preparing the carbon dioxide corrosion inhibitor according to claim 6, characterized in that, In steps S1, S2, S4, S5 and S6, the temperature rising rate is controlled to be 4-5℃ / min.

9. The method for preparing the carbon dioxide corrosion inhibitor according to claim 6, characterized in that, In step S1, after the addition of sodium hydroxide, stirring is continued for 1.8-2.2h.

10. The method for preparing the carbon dioxide corrosion inhibitor according to claim 6, characterized in that, In step S2, the concentrated sulfuric acid is slowly added into the reaction kettle in multiple times.

11. The method for preparing the carbon dioxide corrosion inhibitor according to claim 6, characterized in that, In step S3, the centrifuge is controlled to centrifuge at a speed of 1500-2000r / min for 0.5-1.5h.

12. The method for preparing the carbon dioxide corrosion inhibitor according to claim 6, characterized in that, In step S6, the water in the mixture is separated using a reflux water trap, and the reflux water trap is maintained for 2-2.5h.

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