Oilfield composite desulfurizer and preparation method thereof

Abstract

The invention belongs to the technical field of desulfurizer preparation, and particularly relates to an oil field composite desulfurizer and a preparation method thereof. The compound desulfurizer for the oil field is prepared from the following raw materials in percentage by mass: 12 to 14 percent of 6-tridecyl-1, 3, 5-triazine-2, 4-diamine, 25 to 27 percent of tetramethylguanidine lactate, 7 to 9 percent of glutamic acid-N, N-ferric diacetate, 3.6 to 4.0 percent of sodium dioctyl sulfosuccinate, 1.0 to 1.3 percent of glyceryl polyoxypropylene polyoxyethylene ether and the balance of water. The compound desulfurizer for the oil field has the advantages that the desulfurization speed is high, the desulfurization depth and durability are considered, and the problems that a traditional desulfurizer is easy to emulsify and poor in compatibility with crude oil are solved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of desulfurizer preparation, and particularly relates to an oilfield composite desulfurizer and a preparation method thereof. BACKGROUND

[0002] The H2S generation mechanism in crude oil is mainly as follows: the inorganic cause of hydrogen sulfide is mainly the thermal chemical reduction of sulfate and the chemical decomposition of pyrite, the organic chemical cause of hydrogen sulfide is mainly the generation through mercaptan or sulfide, and the biological cause of hydrogen sulfide is mainly the generation of H2S in the process of oil formation through various complex chemical and biochemical actions such as hydrolysis, oxidation and bacterial degradation. In the process of oil exploitation, bacterial sulfate reduction is a very important generation mechanism. Under anaerobic conditions in an oil reservoir, sulfate-reducing bacteria can efficiently reduce sulfate to generate a large amount of H2S.

[0003] The presence of hydrogen sulfide in the process of oil extraction and crude oil gathering and transportation is a major challenge that needs to be solved urgently. The presence of hydrogen sulfide in oil products: ①causes serious corrosion of pipelines and equipment, resulting in a significant increase in gathering and transportation costs; ②causes great environmental pollution and directly endangers personal safety due to its high toxicity and volatility; and ③causes problems such as excessive sulfur content in finished oil products, poor oil product quality and unqualified oil products. Therefore, how to reduce the hydrogen sulfide content of crude oil to the limit before the crude oil is extracted and to zero after the crude oil is extracted is a problem that must be solved by each oilfield.

[0004] At present, the methods for treating hydrogen sulfide in oil wells at home and abroad include physical methods, biological methods and chemical methods. The physical method mainly includes physical adsorption and membrane separation. The biological method is to use various sulfur bacteria and sulfur bacillus to treat hydrogen sulfide. The chemical method mainly includes oxidation, acid-base neutralization reaction and sulfide precipitation. These methods have their own advantages and disadvantages. The acid-base neutralization method has the advantages of fast desulfurization rate, safety and low labor intensity, but the disadvantage is that the cost of desulfurization is relatively high if the raw materials are not properly selected.

[0005] Chinese patent CN110564394B discloses a desulfurizer for thick oil thermal recovery wells, which is prepared by compounding epoxy propyl linked imidazole and nitrate salt, and can remove hydrogen sulfide and mercaptan. However, the raw material nitrate salt can be converted into nitrite in a high-temperature acidic oil well, accelerating the corrosion of equipment, and the epoxy group is prone to ring-opening at high temperatures, resulting in a decrease in activity. Since the product was applied in the isolated island oil production plant, the desulfurization effect of some high-temperature wells is better than that of triazine desulfurizers, but the treatment effect is poor.

[0006] Therefore, it is necessary to desulfurize crude oil to a safe concentration. The desulfurizer used in the early stage is mostly a mixed solution of strong alkaline organic amine and high salt content, which reacts with acidic substances in the crude oil to generate macromolecular organic salt substances while desulfurizing, thereby playing a role of surfactant, causing serious emulsification of the crude oil, and causing a series of problems such as difficulty in crude oil demulsification, crude oil dehydration and desalination, and poisoning of downstream refining catalysts. Therefore, it has been a technical problem to be solved by those skilled in the art to prepare a desulfurizer capable of solving the defects of easy hydrolysis and poor desulfurization effect. SUMMARY

[0007] The purpose of the present application is to provide an oilfield composite desulfurizer which has a relatively rapid desulfurization speed, and also takes into account the desulfurization depth and durability. The present application also provides a preparation method thereof.

[0008] The oilfield composite desulfurizer according to the present application has the following raw material composition in mass percentage: 6-tridecyl-1,3,5-triazine-2,4-diamine 12-14%, tetramethyl guanidine lactate 25-27%, iron glutamate-N,N-diacetic acid 7-9%, sodium sulfosuccinic acid diisooctyl ester 3.6-4.0%, glycerol polyoxypropylene polyoxyethylene ether 1.0-1.3%, and water as the balance.

[0009] The structural formula of 6-tridecyl-1,3,5-triazine-2,4-diamine is as follows: .

[0010] The preparation method of iron glutamate-N,N-diacetic acid comprises the following steps: ① Dissolving tetrasodium glutamate diacetate in deionized water to prepare a tetrasodium glutamate diacetate solution; ② Dissolving ferric chloride hexahydrate in deionized water to prepare a ferric salt solution; ③ Under stirring, the ferric salt solution prepared in step ② is added to the tetrasodium glutamate diacetate solution, the molar ratio of tetrasodium glutamate diacetate to Fe 3+ is controlled to be 1.2:1, then a sodium hydroxide solution is added to adjust the pH value of the reaction system to 9.0, and the reaction is carried out at 50-55℃ for 1.5h. After the reaction is completed, the reaction system is cooled to room temperature, and insoluble substances are removed by filtration to prepare iron glutamate-N,N-diacetic acid.

[0011] In step ①, the mass concentration of the tetrasodium glutamate diacetate solution is 25%, and in step ②, the mass concentration of the ferric salt solution is 20%.

[0012] The preparation method of the oilfield composite desulfurizer according to the present application comprises the following steps: (1) in the reaction device, 60% of deionized water of the total mass of deionized water is added, and tetramethyl guanidine lactate is added under stirring until completely dissolved; (2) sodium diisooctyl sulfosuccinate is added, and stirring is continued until the solution is transparent; (3) 6-tridecyl-1,3,5-triazine-2,4-diamine is added, and the temperature is raised to 40-42℃ and stirred until completely dispersed; (4) glutamic acid-N,N-iron diacetate is added to the reaction system of step (3) and stirred uniformly; (5) glycerol polyoxypropylene polyoxyethylene ether is added and stirred uniformly, and then the remaining deionized water is added and stirred uniformly, to prepare the oil field composite desulfurizer.

[0013] In step (1), the stirring speed is 400r / min, the stirring time is 10-13min, and the stirring temperature is room temperature.

[0014] In step (2), the stirring time is 15-17min, the stirring speed is 400r / min, and the stirring temperature is room temperature.

[0015] In step (3), the stirring speed is 800r / min, and the stirring time is 25-30min.

[0016] In step (4), the stirring speed is 400r / min, the stirring temperature is 35-38℃, and the stirring time is 10-12min.

[0017] In step (5), the stirring speed is 400r / min, the stirring temperature is 40-42℃, glycerol polyoxypropylene polyoxyethylene ether is added, and stirring and mixing are carried out for 10-12min, then the remaining deionized water is added, and stirring and mixing are carried out for 20-23min.

[0018] The prepared oil field composite desulfurizer product is a light yellow transparent uniform liquid, the pH value is 10.8-11.2, and there is no stratification after storage at 40℃ for 30 days.

[0019] Compared with the prior art, the present application has the following beneficial effects: (1) The oilfield composite desulfurizer disclosed by the application takes 6-tridecyl-1,3,5-triazine-2,4-diamine, tetramethyl guanidine lactate and glutamic acid-N,N-diacetic iron as main desulfurizing substances, and the three substances have a synergistic effect, wherein the long-chain alkyl of 6-tridecyl-1,3,5-triazine-2,4-diamine ensures oil phase permeation, has an irreversible chemical reaction with hydrogen sulfide, and reduces the hydrogen sulfide concentration in a very short time; the tetramethyl guanidine lactate maintains an alkaline environment of the system, ensures that 6-tridecyl-1,3,5-triazine-2,4-diamine and glutamic acid-N,N-diacetic iron can work in the best pH environment, and the lactate ion can also solubilize and stabilize, and the glutamic acid-N,N-diacetic iron can deeply remove trace H2S remaining after triazine reaction, convert the H2S into elemental sulfur, and improve desulfurization depth and completeness. The three substances have a synergistic effect, and fundamentally ensure removal of hydrogen sulfide. In addition, the presence of sulfosuccinic acid diisooctyl sodium ester in the raw material can make the desulfurizer quickly remove oil film, asphaltene and biological film, reduce oil-water interfacial tension, shorten the time for the desulfurizer to take effect, glycerol polyoxypropylene polyoxyethylene ether inhibits foam generated due to a surfactant in the treatment process, prevents air lock, and ensures that the whole treatment process is smoothly carried out.

[0020] (2) The oilfield composite desulfurizer disclosed by the application has a relatively rapid desulfurization speed, and simultaneously considers desulfurization depth and durability, and avoids problems of easy emulsification and poor compatibility with crude oil of traditional desulfurizers.

[0021] (3) The preparation method of the oilfield composite desulfurizer disclosed by the application is simple in operation and mild in conditions, greatly alleviates problems of subsequent treatments such as demulsification, dehydration and desalination caused by emulsification of crude oil due to traditional desulfurizers, and saves a large amount of comprehensive treatment cost for oilfields. DETAILED DESCRIPTION

[0022] Example 1 The oilfield composite desulfurizer in the example 1 is prepared from the following raw materials in mass percentage: 6-tridecyl-1,3,5-triazine-2,4-diamine 13%, tetramethyl guanidine lactate 26%, glutamic acid-N,N-diacetic iron 8%, sulfosuccinic acid diisooctyl sodium ester 3.8%, glycerol polyoxypropylene polyoxyethylene ether 1.1%, and water as the balance.

[0023] The structural formula of the 6-tridecyl-1,3,5-triazine-2,4-diamine is as follows: .

[0024] The preparation method of the glutamic acid-N,N-diacetic iron comprises the following steps: ① Glutamic acid diacetate tetrasodium is dissolved in deionized water to prepare a glutamic acid diacetate tetrasodium solution; (ii) dissolving ferric chloride hexahydrate in deionized water to prepare a ferric salt solution; (iii) under stirring, adding the ferric salt solution prepared in step (ii) into the tetrasodium glutamate diacetate solution, controlling the molar ratio of tetrasodium glutamate diacetate to Fe 3+ to be 1.2:1, then adding a sodium hydroxide solution to adjust the pH value of the reaction system to 9.0, reacting at 53°C for 1.5 h, after the reaction is completed, cooling to room temperature, removing the insoluble substances by filtration, to prepare ferric glutamate-N,N-diacetate.

[0025] In step (i), the mass concentration of the tetrasodium glutamate diacetate solution is 25%, and in step (ii), the mass concentration of the ferric salt solution is 20%.

[0026] The preparation method of the oil field composite desulfurizer described in this embodiment 1 is composed of the following steps: (1) adding deionized water accounting for 60% of the total mass of deionized water in the reaction device, and adding tetramethyl guanidine lactate under stirring until completely dissolved; (2) adding sodium diisooctyl sulfosuccinate, and continuing to stir until the solution is transparent; (3) adding 6-tridecyl-1,3,5-triazine-2,4-diamine, and stirring at a temperature of 41°C until completely dispersed; (4) adding ferric glutamate-N,N-diacetate into the reaction system of step (3) and stirring uniformly; (5) adding glycerol polyoxypropylene polyoxyethylene ether, stirring uniformly, and then adding the remaining deionized water to prepare the oil field composite desulfurizer.

[0027] In step (1), the stirring speed is 400 r / min, the stirring time is 11 min, and the stirring temperature is room temperature.

[0028] In step (2), the stirring time is 16 min, the stirring speed is 400 r / min, and the stirring temperature is room temperature.

[0029] In step (3), the stirring speed is 800 r / min, and the stirring time is 27 min.

[0030] In step (4), the stirring speed is 400 r / min, the stirring temperature is 36°C, and the stirring time is 11 min.

[0031] In step (5), the stirring speed is 400 r / min, the stirring temperature is 41°C, glycerol polyoxypropylene polyoxyethylene ether is added, and stirring and mixing are performed for 11 min, then the remaining deionized water is added, and stirring and mixing are performed for 21 min.

[0032] The oilfield composite desulfurizer prepared in Example 1 is a light yellow transparent uniform liquid, with a pH value of 11.2, and no stratification after being stored at 40℃ for 30 days.

[0033] Example 2 The oilfield composite desulfurizer described in this Example 2 has the following raw material composition in mass percentage: 6-tridecyl-1,3,5-triazine-2,4-diamine 12%, tetramethyl guanidine lactate 25%, iron glutamate-N,N-diacetic acid 9%, sodium sulfosuccinic acid diisooctyl ester 4.0%, glycerol polyoxypropylene polyoxyethylene ether 1.0%, and water as the balance.

[0034] The structural formula of 6-tridecyl-1,3,5-triazine-2,4-diamine is as follows: .

[0035] The preparation method of iron glutamate-N,N-diacetic acid comprises the following steps: ① Tetrasodium glutamate diacetate is dissolved in deionized water to prepare a tetrasodium glutamate diacetate solution; ② Ferric chloride hexahydrate is dissolved in deionized water to prepare a ferric salt solution; ③ The ferric salt solution prepared in step ② is added to the tetrasodium glutamate diacetate solution under stirring, the molar ratio of tetrasodium glutamate diacetate to Fe 3+ is controlled to be 1.2:1, then a sodium hydroxide solution is added to adjust the pH value of the reaction system to 9.0, and the reaction is carried out at 50℃ for 1.5h. After the reaction is completed, the system is cooled to room temperature, and the insoluble substances are removed by filtration to prepare iron glutamate-N,N-diacetic acid.

[0036] In step ①, the mass concentration of the tetrasodium glutamate diacetate solution is 25%, and in step ②, the mass concentration of the ferric salt solution is 20%.

[0037] The preparation method of the oilfield composite desulfurizer described in this Example 2 comprises the following steps: (1) 60% of deionized water based on the total mass of deionized water is added to a reaction device, and tetramethyl guanidine lactate is added under stirring until it is completely dissolved; (2) Sodium sulfosuccinic acid diisooctyl ester is added, and the stirring is continued until the solution is transparent; (3) 6-tridecyl-1,3,5-triazine-2,4-diamine is added, and the temperature is raised to 40℃ for stirring until it is completely dispersed; (4) Iron glutamate-N,N-diacetic acid is added to the reaction system of step (3) and stirred uniformly; (5) Glycerol polyoxypropylene polyoxyethylene ether is added and stirred uniformly, and then the remaining deionized water is added and stirred uniformly to prepare the oilfield composite desulfurizer.

[0038] The stirring speed in step (1) is 400 r / min, the stirring time is 10 min, and the stirring temperature is room temperature.

[0039] The stirring time in step (2) is 17 min, the stirring speed is 400 r / min, and the stirring temperature is room temperature.

[0040] The stirring speed in step (3) is 800 r / min, and the stirring time is 25 min.

[0041] The stirring speed in step (4) is 400 r / min, the stirring temperature is 38℃, and the stirring time is 12 min.

[0042] The stirring speed in step (5) is 400 r / min, the stirring temperature is 40℃, glycerol polyoxypropylene polyoxyethylene ether is added, stirred and mixed for 10 min, then the remaining deionized water is added, stirred and mixed for 20 min.

[0043] The oil field composite desulfurizer prepared in Example 2 is a light yellow transparent uniform liquid, the pH value is 10.8, and there is no stratification after being stored at 40℃ for 30 days.

[0044] Example 3 The oil field composite desulfurizer described in this example 3, in mass percentage, the raw material composition is as follows: 6-tridecyl-1,3,5-triazine-2,4-diamine 14%, tetramethyl guanidine lactate 27%, glutamic acid-N,N-diacetic acid iron 7%, sodium sulfosuccinic acid diisooctyl ester 3.6%, glycerol polyoxypropylene polyoxyethylene ether 1.3%, and water as the balance.

[0045] The structural formula of 6-tridecyl-1,3,5-triazine-2,4-diamine is as follows: .

[0046] The preparation method of glutamic acid-N,N-diacetic acid iron comprises the following steps: ①Glutamic acid diacetate tetrasodium is dissolved in deionized water to prepare a glutamic acid diacetate tetrasodium solution; ②Iron salt solution is prepared by dissolving ferric chloride hexahydrate in deionized water; ③Under stirring conditions, the iron salt solution prepared in step ② is added to the glutamic acid diacetate tetrasodium solution, the molar ratio of glutamic acid diacetate tetrasodium to Fe 3+ is controlled to be 1.2:1, then sodium hydroxide solution is added to adjust the pH value of the reaction system to 9.0, and the reaction is carried out at 55℃ for 1.5 h. After the reaction is completed, it is cooled to room temperature, and the insoluble matter is removed by filtration to prepare glutamic acid-N,N-diacetic acid iron.

[0047] Wherein: the mass concentration of glutamic acid diacetic acid tetrasodium solution in step 1 is 25%, and the mass concentration of iron salt solution in step 2 is 20%.

[0048] The preparation method of the oil field composite desulfurizer described in this embodiment 3 is composed of the following steps: (1) Add deionized water accounting for 60% of the total mass of deionized water in the reaction device, and add tetramethyl guanidine lactate under stirring until completely dissolved; (2) Add sodium diisooctyl sulfosuccinate, and continue to stir until the solution is transparent; (3) Add 6-tridecyl-1,3,5-triazine-2,4-diamine, and stir to completely disperse at a temperature of 42℃; (4) Add iron glutamic acid-N,N-diacetate to the reaction system of step (3) and stir to mix evenly; (5) Add glycerol polyoxypropylene polyoxyethylene ether and stir to mix evenly, and then add the remaining deionized water and stir to mix evenly, to prepare the oil field composite desulfurizer.

[0049] Wherein: the stirring speed in step (1) is 400 r / min, the stirring time is 13 min, and the stirring temperature is room temperature.

[0050] The stirring time in step (2) is 15 min, the stirring speed is 400 r / min, and the stirring temperature is room temperature.

[0051] The stirring speed in step (3) is 800 r / min, and the stirring time is 30 min.

[0052] The stirring speed in step (4) is 400 r / min, the stirring temperature is 35℃, and the stirring time is 10 min.

[0053] The stirring speed in step (5) is 400 r / min, the stirring temperature is 42℃, glycerol polyoxypropylene polyoxyethylene ether is added, and stirring and mixing are carried out for 12 min, then the remaining deionized water is added, and stirring and mixing are carried out for 23 min.

[0054] The oil field composite desulfurizer prepared in example 3 has a light yellow transparent uniform liquid appearance, a pH value of 11.0, and no stratification after being stored at 40℃ for 30 days.

[0055] Comparative example 1 The preparation method of the oil field composite desulfurizer described in this comparative example 1 is the same as that of example 1, and the only difference is that the raw material composition is different. The oil field composite desulfurizer described in this comparative example 1 has the following raw material composition in mass percentage: tetramethyl guanidine lactate 26%, iron glutamic acid-N,N-diacetate 8%, sodium diisooctyl sulfosuccinate 3.8%, glycerol polyoxypropylene polyoxyethylene ether 1.1%, and the balance is water.

[0056] Comparative Example 2 The preparation method of the oilfield composite desulfurizer described in Comparative Example 2 is the same as that of Example 1, and the only difference is that the raw material composition is different. The oilfield composite desulfurizer described in Comparative Example 2 has the following raw material composition in mass percentage: 6-tridecyl-1, 3, 5-triazine-2, 4-diamine 13%, iron glutamic acid-N, N-diacetate 8%, sodium sulfosuccinic acid diisooctyl ester 3.8%, glycerol polyoxypropylene polyoxyethylene ether 1.1%, and water as the balance.

[0057] Comparative Example 3 The preparation method of the oilfield composite desulfurizer described in Comparative Example 3 is the same as that of Example 1, and the only difference is that the raw material composition is different. The oilfield composite desulfurizer described in Comparative Example 3 has the following raw material composition in mass percentage: 6-tridecyl-1, 3, 5-triazine-2, 4-diamine 13%, tetramethyl guanidine lactate 26%, sodium sulfosuccinic acid diisooctyl ester 3.8%, glycerol polyoxypropylene polyoxyethylene ether 1.1%, and water as the balance.

[0058] The desulfurization capacity detection method refers to ASTM D4810-88 (1999) "Standard Test Method for Hydrogen Sulfide Content of Natural Gas by Colorimetric Detector Tube Method". First, 1L of oilfield production fluid is introduced into a sealed container, the container is immediately sealed, and the container is placed in a shaking box for shaking for 10 minutes. The gas sample is taken from the top of the sealed container to detect the hydrogen sulfide concentration, which is recorded as the blank hydrogen sulfide concentration C0. A certain amount of desulfurizer is injected into the sealed container, and then 1L of oilfield production fluid is introduced, the container is immediately sealed, and the container is placed in a shaking box for shaking for 10 minutes. The gas sample is taken from the top of the sealed container to detect the hydrogen sulfide concentration, which is recorded as the hydrogen sulfide concentration C.

[0059] The desulfurization performance of the desulfurizer is evaluated by the desulfurization rate, and the higher the desulfurization rate, the better the desulfurization performance. The desulfurization rate refers to the percentage of the decrease in hydrogen sulfide content before and after the oil sample is added to the desulfurizer. The desulfurization rate is calculated according to the following formula: X = (C0-C) / C0*100%, where X is the desulfurization rate, C0 is the measured hydrogen sulfide content before adding the desulfurizer, and C is the measured desulfurizer content after adding the desulfurizer. The test platform is a certain oilfield crude oil, the concentration of the added desulfurizer is 100mg / L, and the hydrogen sulfide content in the crude oil is 2500mg / L. The desulfurization rate is tested according to the above method, and the results are shown in Table 1 below: Table 1 Test results of desulfurization performance of desulfurizer

[0060] From the above Table 1, it can be seen that the desulfurization rates of the oilfield composite desulfurizers prepared in Examples 1-3 are much higher than those of Comparative Examples 1-3. In Comparative Examples 1-3, the raw material 6-tridecyl-1,3,5-triazine-2,4-diamine, tetramethyl guanidine lactate and ferrous glutamate-N,N-diacetate are missing, respectively, resulting in a great decrease in the desulfurization efficiency of the prepared oilfield composite desulfurizers. It can be seen from Comparative Examples 1-3 that the raw materials for preparing the oilfield composite desulfurizer prepared in the present application have a synergistic effect.

[0061] The above description is merely preferred embodiments of the present application, but not a limitation of the present application. Any modification, equivalent replacement and improvement made by any person with the technical contents disclosed in the present application shall fall within the protection scope of the present application.

Claims

1. An oilfield composite desulfurizer, characterized by: The raw material composition is as follows in percentage by mass: 12-14% of 6-tridecyl-1,3,5-triazine-2,4-diamine, 25-27% of tetramethylguanidine lactate, 7-9% of glutamic acid-N,N-diacetate ferric, 3.6-4.0% of sodium diethyl sulfosuccinate, 1.0-1.3% of glycerol polyoxypropylene polyoxyethylene ether, and the balance of water.

2. The oilfield composite desulfurizer according to claim 1, characterized in that: The structural formula of 6-tridecyl-1,3,5-triazine-2,4-diamine is: 。 3. The oilfield composite desulfurizer according to claim 1, characterized in that: The preparation method of glutamic acid-N,N-diacetate ferric comprises the following steps: ① Dissolve tetrasodium glutamate diacetate in deionized water to prepare a tetrasodium glutamate diacetate solution; ② Dissolving ferric chloride hexahydrate in deionized water to prepare an iron salt solution; ③ Under stirring conditions, add the iron salt solution prepared in step ② to the tetrasodium glutamate diacetate solution to control the reaction between tetrasodium glutamate diacetate and Fe 3+ The molar ratio of the reaction mixture is 1.2:1, and then sodium hydroxide solution is added to adjust the pH value of the reaction system to 9.

0. The reaction is carried out at 50-55° C. for 1.5 hours. After the reaction is completed, the mixture is cooled to room temperature and the insoluble matter is removed by filtration to prepare glutamic acid-N,N-diacetate ferric.

4. The oilfield composite desulfurizer according to claim 3, characterized in that: The mass concentration of the tetrasodium glutamate diacetate solution in step ① is 25%, and the mass concentration of the iron salt solution in step ② is 20%.

5. A method for preparing the oilfield composite desulfurizer according to claim 1, characterized in that: It consists of the following steps: (1) Add 60% of the total mass of deionized water to the reaction device, add tetramethylguanidine lactate while stirring, and stir until completely dissolved; (2) Add sodium dioctyl sulfosuccinate and continue stirring until the solution becomes transparent; (3) Add 6-tridecyl-1,3,5-triazine-2,4-diamine, heat to 40-42°C and stir until completely dispersed; (4) Add glutamic acid-N,N-diacetate iron to the reaction system of step (3) and stir to mix; (5) Add glycerol polyoxypropylene polyoxyethylene ether and stir to mix evenly, then add the remaining deionized water and stir to mix evenly to prepare an oilfield composite desulfurizer.

6. The method for preparing the oilfield composite desulfurizer according to claim 5, characterized in that: In step (1), the stirring speed is 400 r / min, the stirring time is 10-13 min, and the stirring temperature is room temperature.

7. The method for preparing the oilfield composite desulfurizer according to claim 5, characterized in that: In step (2), the stirring time is 15-17 min, the stirring speed is 400 r / min, and the stirring temperature is room temperature.

8. The method for preparing the oilfield composite desulfurizer according to claim 5, characterized in that: In step (3), the stirring speed is 800 r / min and the stirring time is 25-30 min.

9. The method for preparing the composite desulfurizer for oil fields according to claim 5, characterized in that: In step (4), the stirring speed is 400 r / min, the stirring temperature is 35-38° C., and the stirring time is 10-12 min.

10. The method for preparing the composite desulfurizer for oil fields according to claim 5, characterized in that: In step (5), the stirring speed is 400 r / min, the stirring temperature is 40-42° C., glycerol polyoxypropylene polyoxyethylene ether is added, and the mixture is stirred for 10-12 minutes, and then the remaining deionized water is added and the mixture is stirred for 20-23 minutes.

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