A Gemini Surfactant, an Acidification Corrosion Inhibitor and its Preparation Method

Abstract

This application belongs to the field of oilfield chemistry, and specifically relates to a gemini surfactant, an acid corrosion inhibitor, and its preparation method. The preparation method of the gemini surfactant includes mixing N-hydroxymethylimidazoline, acyl chloride, tetrahydrofuran, and triethylamine, refluxing at 60-70°C for 2-3 hours, followed by rotary evaporation to obtain a solid intermediate product. After washing, the intermediate product is added to a mixed solution of n-hexane and 1,4-dibromobutene, stirred at room temperature for 10-12 hours, and the precipitate is collected to obtain the gemini surfactant. The gemini surfactant synthesized in this application exhibits chain scission of the ester group on its hydrophobic chain at high temperatures, consuming energy on the metal surface to protect the adsorption capacity of the gemini surfactant on the metal surface. Furthermore, the unsaturated groups on the bridging group of the gemini surfactant form covalent π bonds with the metal, strengthening the adhesion to the metal surface. The acid corrosion inhibitor prepared using this surfactant can effectively reduce the corrosion rate at high temperatures, meeting industry standards for corrosion inhibitors.

Description

Technical Field

[0001] This application belongs to the field of oilfield chemistry, and specifically relates to a gemini surfactant, an acidification corrosion inhibitor, and a method for preparing the same. Background Technology

[0002] As oil and gas exploration and development deepens, more and more ultra-deep wells are being drilled. These ultra-deep wells are often located in reservoirs with excessive depth and dense lithology, requiring reservoir stimulation for effective exploration and production. Common reservoir acidizing stimulation involves injecting high-concentration, corrosive acids into the reservoir. To protect downhole tubing and equipment, corrosion inhibitors need to be injected along with the acid. However, the bottom hole temperature in ultra-deep wells can sometimes reach 231°C, requiring corrosion inhibitors with high temperature resistance.

[0003] Currently used corrosion inhibitors mainly rely on their adsorption on the metal surface to form an adsorption layer, thereby isolating the acid from the metal. The strength of the corrosion inhibitor's protective effect on the metal and its temperature resistance mainly depends on the inhibitor's adsorption capacity on the metal surface; the stronger the adsorption capacity, the better the protective ability and temperature resistance. Currently reported corrosion inhibitors are mainly quaternary ammonium salts. Patent CN114634803A uses quinoline-chloromethylnaphthalene quaternary ammonium salt, bisquinoline-1,4-bischloromethylnaphthalene quaternary ammonium salt, and 1,3,5-trimethylhexylhydroxy-1,3,5-triazine as the main agents to obtain a corrosion inhibitor with a temperature resistance of 180–200℃. Patent CN116410154A uses acylthiazole compounds, aromatic aldehydes, and polyethylene polyamines as raw materials, and synthesizes compounds through the Mannich reaction that can meet the 180℃ requirement. The corrosion inhibitor developed in the paper "Development and Performance Evaluation of High-Temperature Acid Corrosion Inhibitors" can meet the corrosion protection requirements at 200℃. However, the aforementioned quaternary ammonium salts and other types of corrosion inhibitors have limited adsorption sites and are easily desorbed at high temperatures above 200°C, thus failing to protect metals in the temperature environment of ultra-deep well bottoms.

[0004] Therefore, it is necessary to develop a twin surfactant and acid corrosion inhibitor with strong adsorption capacity to meet the needs of ultra-deep well development. Summary of the Invention

[0005] To address the above problems, this application discloses a gemini surfactant with the following structural formula:

[0006]

[0007] Where R is or .

[0008] Furthermore, the two R's in the structural formula may be the same or different.

[0009] Preferably, the two R's in the structural formula are the same.

[0010] This application also discloses a method for preparing the above-mentioned strongly adsorbing gemini surfactant, comprising:

[0011] N-hydroxymethylimidazoline, acyl chloride, tetrahydrofuran, and triethylamine were mixed and refluxed at 60-70°C for 2-3 hours, followed by rotary evaporation to obtain a solid intermediate product.

[0012] The solid intermediate was washed and added to a mixed solution of hexane and 1,4-dibromobutene. After stirring at room temperature for 10-12 hours, the precipitate was collected to obtain a strongly adsorbed gemini surfactant.

[0013] Furthermore, the molar ratio of N-hydroxymethylimidazoline to acyl chloride is not less than 2:3 and not more than 1:1.

[0014] Furthermore, the acyl chloride is a C3-C6 alkyl acyl chloride.

[0015] Furthermore, the C3-C6 alkyl acyl chloride is butyryl chloride or hexanoyl chloride.

[0016] Furthermore, the mass of tetrahydrofuran is 2-3 times the mass of the N-hydroxymethylimidazoline.

[0017] Furthermore, the mass of triethylamine is 5-10% of the mass of the N-hydroxymethylimidazoline.

[0018] Furthermore, the mass of n-hexane is 2-3 times the mass of the N-hydroxymethylimidazoline.

[0019] Furthermore, the mass of 1,4-dibromobutene is 10-20% of the mass of the N-hydroxymethylimidazoline.

[0020] This application also discloses an acid corrosion inhibitor, wherein the components of the acid corrosion inhibitor, by mass percentage, include 15-30% of the above-mentioned strong adsorption gemini surfactant, 20-30% of small molecule alcohol, 2-6% of propynyl alcohol, 5-10% of formic acid and 0.5-2% of alkyl polyoxyethylene ether, with the remainder being water.

[0021] Furthermore, the small molecule alcohol is a mixture of methanol and ethylene glycol, with a mass ratio of methanol to ethylene glycol of 2-5:1.

[0022] Furthermore, the alkyl group in alkyl polyoxyethylene ether is octyl or decanyl.

[0023] The technical effects and advantages of this application are as follows:

[0024] This application synthesizes a strong adsorption Gemini surfactant. The ester group on its hydrophobic chain breaks at high temperature, consuming energy on the metal surface to protect the adsorption capacity of the Gemini surfactant on the metal surface. The unsaturated group on the bridging group of the Gemini surfactant forms a covalent π bond with the metal, strengthening the adhesion to the metal surface. The acid corrosion inhibitor prepared by it can effectively reduce the corrosion rate at 180℃, 200℃ and 220℃, meeting the industry standard for corrosion inhibitors.

[0025] Other features and advantages of this application will be set forth in the description which follows, and will be apparent in part from the description, or may be learned by practicing the application. The objectives and other advantages of this application may be realized and obtained by means of the structures pointed out in the description, claims and drawings. Attached Figure Description

[0026] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0027] Figure 1 This is a flowchart illustrating a method for preparing a strongly adsorbing gemini surfactant according to an embodiment of this application. Detailed Implementation

[0028] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0029] To meet the need for high-temperature corrosion inhibitors in ultra-deep well development, this application discloses a gemini surfactant with the following structural formula:

[0030]

[0031] Where R is or .

[0032] In some embodiments of this application, the two Rs in the structural formula may be the same or different. Preferably, the two Rs in the structural formula are the same.

[0033] The strong adsorption Gemini surfactant designed in this application has an ester group on its hydrophobic chain that breaks at high temperature, consuming energy on the metal surface to protect the adsorption capacity of the Gemini surfactant on the metal surface. The unsaturated group on the bridging group of the strong adsorption Gemini surfactant can form a covalent π bond with the metal, strengthening the adhesion to the metal surface.

[0034] like Figure 1 As shown, this application also discloses a method for preparing the above-mentioned gemini surfactant, comprising:

[0035] N-hydroxymethylimidazoline, acyl chloride, tetrahydrofuran, and triethylamine were mixed and refluxed at 60-70°C for 2-3 hours, followed by rotary evaporation to obtain a solid intermediate product.

[0036] After washing the solid intermediate, it was added to a mixed solution of hexane and 1,4-dibromobutene. The mixture was stirred at room temperature for 10-12 hours, and the precipitate was collected to obtain a strongly adsorbed gemini surfactant.

[0037] In some embodiments of this application, the molar ratio of N-hydroxymethylimidazoline to acyl chloride is not less than 2:3 and not more than 1:1.

[0038] In some embodiments of this application, the acyl chloride is a C3-C6 alkyl acyl chloride, preferably a butyryl chloride or a caproyl chloride.

[0039] In some embodiments of this application, the mass of tetrahydrofuran is 2-3 times the mass of N-hydroxymethylimidazoline.

[0040] In some embodiments of this application, the mass of triethylamine is 5-10% of the mass of N-hydroxymethylimidazoline.

[0041] In some embodiments of this application, the mass of n-hexane is 2-3 times the mass of N-hydroxymethylimidazoline.

[0042] In some embodiments of this application, the mass of 1,4-dibromobutene is 10-20% of the mass of N-hydroxymethylimidazoline.

[0043] This application also discloses an acid corrosion inhibitor, wherein the components of the acid corrosion inhibitor, by mass percentage, include 15-30% of the above-mentioned strong adsorption gemini surfactant, 20-30% of small molecule alcohol, 2-6% of propynyl alcohol, 5-10% of formic acid and 0.5-2% of alkyl polyoxyethylene ether, with the remainder being water.

[0044] In some embodiments of this application, the small molecule alcohol is a mixture of methanol and ethylene glycol, with a mass ratio of methanol to ethylene glycol of 2-5:1.

[0045] To better illustrate this solution, the following embodiments are provided.

[0046] Example 1

[0047] 100.12 kg of N-hydroxymethylimidazoline and 106.55 kg of butyryl chloride were reacted in 300.36 kg of tetrahydrofuran with 10 kg of triethylamine as a catalyst. The mixture was refluxed at 70 °C for 2 h and then rotary evaporated to obtain a brown solid intermediate product.

[0048] The brown solid intermediate was washed three times with 400 kg of methanol and placed in a flask. 300 kg of n-hexane was added, followed by 20 kg of 1,4-dibromobutene. The mixture was stirred at room temperature for 12 h, and the precipitate was collected by filtration to obtain a strongly adsorbed gemini surfactant.

[0049] Example 2

[0050] 81 kg of N-hydroxymethylimidazoline was reacted with 161.52 kg of hexanoyl chloride in 162 kg of tetrahydrofuran with 4.05 kg of triethylamine as catalyst. The mixture was refluxed at 70 °C for 2 h and then rotary evaporated to obtain a brown solid intermediate product.

[0051] The brown solid intermediate was washed three times with 243 kg of methanol and placed in a flask. 162 kg of n-hexane was added, followed by 8.1 kg of 1,4-dibromobutene. The mixture was stirred at room temperature for 12 h, and the precipitate was collected by filtration to obtain a strongly adsorbed gemini surfactant.

[0052] Example 3

[0053] 90 kg of N-hydroxymethylimidazoline and 117.2 kg of hexanoyl chloride were reacted in 225 kg of tetrahydrofuran with 6.3 kg of triethylamine as a catalyst. The mixture was refluxed at 60 °C for 3 h and then rotary evaporated to obtain a brown solid intermediate product.

[0054] The brown solid intermediate was washed three times with 324 kg of methanol and placed in a flask. 252 kg of n-hexane was added, followed by 11.7 kg of 1,4-dibromobutene. The mixture was stirred at room temperature for 10 h, and the precipitate was collected by filtration to obtain a strongly adsorbed gemini surfactant.

[0055] Example 4

[0056] 15 kg of the strongly adsorbing Gemini surfactant prepared in Example 1, 15 kg of methanol, 5 kg of ethylene glycol, 3 kg of propynyl alcohol, 5 kg of formic acid, 0.6 kg of octyl polyoxyethylene ether, and 56.4 kg of water were injected into an enamel-lined reactor and stirred at 3000 rpm for 1 hour to obtain an acidification corrosion inhibitor.

[0057] Example 5

[0058] 30 kg of the strongly adsorbing Gemini surfactant prepared in Example 2, 20 kg of methanol, 10 kg of ethylene glycol, 6 kg of propynyl alcohol, 8 kg of formic acid, 2 kg of decanyl polyoxyethylene ether, and 24 kg of water were injected into an enamel-lined reactor and stirred at 3000 rpm for 3 hours to obtain an acidification corrosion inhibitor.

[0059] Example 6

[0060] 20 kg of the strongly adsorbing Gemini surfactant prepared in Example 3, 20 kg of methanol, 4 kg of ethylene glycol, 3 kg of propargyl alcohol, 10 kg of formic acid, 0.5 kg of decanyl polyoxyethylene ether, and 42.5 kg of water were injected into an enamel-lined reactor and stirred at 3000 rpm for 1 hour to obtain an acidification corrosion inhibitor.

[0061] Example 7

[0062] 25 kg of the strongly adsorbing Gemini surfactant prepared in Example 3, 16 kg of methanol, 4 kg of ethylene glycol, 5 kg of propynyl alcohol, 7 kg of formic acid, 1 kg of octyl polyoxyethylene ether, and 42 kg of water were injected into an enamel-lined reactor and stirred at 3000 rpm for 3 hours to obtain an acidification corrosion inhibitor.

[0063] Example 8

[0064] 30 kg of the strongly adsorbing Gemini surfactant prepared in Example 2, 18 kg of methanol, 4 kg of ethylene glycol, 6 kg of propynyl alcohol, 9 kg of formic acid, 1.8 kg of octyl polyoxyethylene ether, and 31.2 kg of water were injected into an enamel-lined reactor and stirred at 3000 rpm for 3 hours to obtain an acidification corrosion inhibitor.

[0065] The corrosion inhibition performance of the acid corrosion inhibitors prepared in Examples 4-8 under ultra-high temperature conditions was tested according to the corrosion rate test method in standard SYT 5405-2019 "Test Methods and Evaluation Indicators for Performance of Acid Corrosion Inhibitors". The results are shown in Table 1. The acid corrosion inhibitors prepared in Examples 4-8 can effectively reduce the corrosion rate at 180℃, 200℃ and 220℃, meeting the industry standard for corrosion inhibitors. Under the same acid solution formulation, the corrosion inhibition performance of the two existing acid corrosion inhibitors decreased significantly at 220℃.

[0066] Table 1. Performance test results of the acid corrosion inhibitors prepared in Examples 4-8 and existing acid corrosion inhibitors.

[0067]

[0068] In summary, this application synthesizes a strong adsorption Gemini surfactant. The ester group on its hydrophobic chain breaks at high temperature, consuming energy on the metal surface to protect the adsorption capacity of the Gemini surfactant on the metal surface. The unsaturated group on the bridging group of the Gemini surfactant forms a covalent π bond with the metal, strengthening the adhesion to the metal surface. The acid corrosion inhibitor prepared using it can effectively reduce the corrosion rate at 180℃, 200℃ and 220℃, meeting the industry standards for corrosion inhibitors.

[0069] Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application.

Claims

1. A gemini surfactant, characterized in that, Its structural formula is: Where R is or .

2. The gemini surfactant according to claim 1, characterized in that, In the structural formula, the two R's are the same.

3. A method for preparing the gemini surfactant according to claim 1 or 2, characterized in that, include: N-hydroxymethylimidazoline, acyl chloride, tetrahydrofuran, and triethylamine were mixed and refluxed at 60-70°C for 2-3 hours, followed by rotary evaporation to obtain a solid intermediate product. The solid intermediate was washed and added to a mixed solution of hexane and 1,4-dibromobutene. After stirring at room temperature for 10-12 h, the precipitate was collected to obtain the Gemini surfactant. The acyl chloride is a C3-C6 alkyl acyl chloride; The C3-C6 alkyl acyl chloride is butyryl chloride or hexanoyl chloride.

4. The preparation method according to claim 3, characterized in that, The molar ratio of N-hydroxymethylimidazoline to acyl chloride is not less than 2:3 and not more than 1:

1.

5. The preparation method according to claim 3, characterized in that, The mass of the tetrahydrofuran is 2-3 times the mass of the N-hydroxymethylimidazoline.

6. The preparation method according to claim 3, characterized in that, The mass of the triethylamine is 5-10% of the mass of the N-hydroxymethylimidazoline.

7. The preparation method according to claim 3, characterized in that, The mass of the n-hexane is 2-3 times the mass of the N-hydroxymethylimidazoline.

8. The preparation method according to claim 3, characterized in that, The mass of the 1,4-dibromobutene is 10-20% of the mass of the N-hydroxymethylimidazoline.

9. An acid corrosion inhibitor, characterized in that, The acid corrosion inhibitor comprises, by mass percentage, 15-30% of the gemini surfactant as described in claim 1 or 2, 20-30% of small molecule alcohol, 2-6% of propargyl alcohol, 5-10% of formic acid and 0.5-2% of alkyl polyoxyethylene ether, with the remainder being water.

10. The acid corrosion inhibitor according to claim 9, characterized in that, The small molecule alcohol is a mixture of methanol and ethylene glycol, with a mass ratio of methanol to ethylene glycol of 2-5:

1.

11. The acid corrosion inhibitor according to claim 9, characterized in that, The alkyl group of the alkyl polyoxyethylene ether is octyl or decyl.

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