Benzimidazolyl Gemini surfactant as well as preparation and application thereof

Abstract

The invention discloses a benzimidazolyl Gemini surfactant as well as preparation and application of the benzimidazolyl Gemini surfactant. The benzimidazolyl Gemini surfactant is a symmetric gemini type compound formed by a benzimidazole group, a styrene group, a sulfonate group and an alkyl chain with a proper length, and the compound has a better oil displacement effect. The surfactant can also reduce the surface tension of a solution in a dose-dependent manner, has relatively strong interfacial activity, excellent shear restorability and wettability, is beneficial to improving the oil recovery rate, and is suitable for multiple aspects such as an oil-soluble viscosity reducer, an oil-displacing agent and a microemulsion internal phase in tertiary oil recovery. The invention provides a method for preparing a surfactant by sulfonation and neutralization after styryl benzimidazole and alkyl diethylene oxide are subjected to ring-opening reaction to obtain a Gemini intermediate, and the synthetic process route has the characteristics of high product surface activity, excellent rheological property and simple synthetic method.

Description

Technical Field

[0001] The present invention relates to a surfactant in the field of petrochemical industry and its preparation and application, in particular to a benzimidazole-based Gemini surfactant and its preparation and application in oil recovery in oilfield chemistry. Background Art

[0002] The world's proven conventional light crude oil reserves account for only about 30% of the total reserves, and the rest are mostly high-viscosity oil resources such as heavy oil, extra-heavy oil, oil sands and asphalt. These high-viscosity resources have poor fluidity and are difficult to recover efficiently using conventional oil recovery technology, resulting in a large amount of residual oil that cannot be effectively mined. To address this problem, tertiary oil recovery (EOR) technology to enhance oil recovery has been widely used, among which chemical flooding technology has become one of the key means to deal with complex oil reservoirs due to its significant production increase effect.

[0003] In chemical flooding technology, the introduction of surfactants is considered to be one of the key means to improve oil recovery. Surfactants effectively reduce the oil-water interfacial tension and promote oil-water emulsification, thereby improving the fluidity of crude oil. Especially in heavy oil and complex reservoirs, surfactants have shown unique advantages. However, existing surfactants have problems such as poor chemical stability, thermal stability and salt resistance in complex reservoir environments, and their production costs are high, which seriously limits their commercial application in actual oil fields.

[0004] The role of surfactants in oil recovery is mainly reflected in reducing the oil-water interfacial tension, changing the wettability of rocks and forming microemulsions, and improving the fluidity of oil-water miscible phases. In recent years, Gemini surfactants have become a research hotspot in the field of chemical oil recovery due to their unique amphiphilic molecular structure, showing stronger surface activity, lower critical micelle concentration and better salt and temperature resistance. Compared with traditional surfactants, Gemini surfactants have lower critical micelle concentrations, better interfacial activity and salt and temperature resistance, especially in improving the fluidity and recovery rate of crude oil.

[0005] At present, oil recovery systems at home and abroad are developing in the direction of low damage, high adaptability, low cost and environmental protection. In order to cope with the dual challenges of global energy shortage and environmental pollution, it is of great practical significance to develop a new type of surfactant with excellent surface activity, temperature and salt resistance, good emulsification and viscosity reduction to meet the increasingly severe needs. Summary of the invention

[0006] Object of the Invention: The object of the present invention is to provide a benzimidazole-based Gemini surfactant with excellent oil displacement effect. Another object of the present invention is to propose a preparation method of the benzimidazole-based Gemini surfactant to solve the problem of how to prepare the benzimidazole-based Gemini surfactant. The third object of the present invention is to propose the application of the benzimidazole-based Gemini surfactant in an oil-soluble viscosity reducer or an oil displacement agent or the internal phase of a microemulsion in tertiary oil recovery to solve the problem of how to obtain an oil-soluble viscosity reducer or an oil displacement agent or the internal phase of a microemulsion in tertiary oil recovery with excellent performance.

[0007] Technical Solution: A benzimidazole-based Gemini surfactant represented by formula (I) according to the present invention:

[0008]

[0009] wherein R 1 is a sulfonate group, and X is a C 1-30 alkyl group.

[0010] In the present invention, the benzimidazole-based Gemini surfactant exhibits excellent chemical stability, thermal stability, and excellent oil displacement effect due to the synergistic effect of the introduced benzimidazole group, styrene group, sulfonate group, and an alkyl chain of appropriate length, and is suitable for oil displacement operations in complex reservoirs.

[0011] Preferably, the cation in the sulfonate group is at least one of Na + , K + , NH 4 + , and X is a C 1-10 linear alkyl group.

[0012] Preferably, the sulfonate group is a sodium sulfonate group, and X is one of methyl, ethyl, and propyl.

[0013] On the other hand, the present invention discloses a preparation method of the above-mentioned benzimidazole-based Gemini surfactant, which includes the following steps:

[0014]

[0015] wherein X is a C 1-30 alkyl group.

[0016] Preferably, the base catalyst includes at least one of KOH and NaOH, the sulfonating agent is selected from at least one of H 2 SO 4 , NaHSO 3 , SO 3 , and the alkali solution is one of an aqueous KOH solution, an aqueous NaOH solution, and ammonia water.

[0017] Preferably, the synthesis reaction conditions of Compound III are as follows: Compound IV is added dropwise to Compound V, then a base catalyst is added. After mixing at room temperature, the temperature is first raised to 30 - 60 °C and reacted for 1 - 4 h, and then the temperature is raised to 60 - 120 °C and reacted for 1 - 6 h to obtain Compound III;

[0018] The synthesis reaction conditions of Compound II are as follows: A sulfonating agent is mixed with Compound III and reacted at 35 - 55 °C for 1 - 3 h to obtain Compound II; the molar ratio of the sulfonating agent to Compound III is 2 - 4:1.

[0019] The synthesis reaction conditions of Compound I are as follows: An alkali solution with a concentration of 20 - 30% is added to the sulfonation reaction product until the sulfonation reaction product is neutral to obtain Compound I.

[0020] Preferably, the preparation method of Compound V is as follows:

[0021]

[0022] Preferably, the molar ratio of o - phenylenediamine to cinnamaldehyde is 1 - 2:1 - 2.

[0023] Preferably, the reaction conditions are as follows: o - phenylenediamine and cinnamaldehyde are mixed in a polar solvent, with boric acid as a catalyst, and reacted at 40 - 80 °C for 2 - 8 h. The polar solvent can be selected from methanol, ethanol, DMSO, and DMF.

[0024] The third aspect of the present invention discloses the application of the above - mentioned benzimidazolyl Gemini surfactant in an oil - soluble viscosity reducer, an oil displacement agent, or the internal phase of a microemulsion in tertiary oil recovery.

[0025] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages:

[0026] 1. The benzimidazolyl Gemini surfactant in the present invention has a good oil displacement effect, and the oil displacement effect is significantly better than that of sodium dodecyl sulfate at the same concentration. This surfactant can also dose - dependently reduce the surface tension of the solution, and at the same time has strong interfacial activity, excellent shear recovery, and wettability. It has a small dosage, low cost, and less damage to the formation, which is beneficial to improving oil recovery. It is applicable to multiple aspects such as oil - soluble viscosity reducers, oil displacement agents, and the internal phase of microemulsions in tertiary oil recovery, and has great market application potential.

[0027] 2. The present invention provides a method for preparing a benzimidazole-based Gemini surfactant. First, o-phenylenediamine reacts with cinnamaldehyde to synthesize styrylbenzimidazole. Then, an ring-opening reaction occurs with alkyldiethylene oxide to obtain a Gemini intermediate, followed by sulfonation and neutralization. This synthetic process route is environmentally friendly, without industrial waste residues, has high surface activity of the product, excellent rheological properties, and a simple synthesis method. Description of the Drawings

[0028] Figure 1 It is a graph showing the surface tension test results of the benzimidazole-based Gemini surfactant prepared in Examples 1-3;

[0029] Figure 2 It is a graph showing the interfacial activity test results of the benzimidazole-based Gemini surfactant prepared in Example 1;

[0030] Figure 3 It is a graph showing the shear recovery test results of the benzimidazole-based Gemini surfactant prepared in Example 1;

[0031] Figure 4 It is a graph showing the wettability test results of the benzimidazole-based Gemini surfactant prepared in Example 1;

[0032] Figure 5 It is a graph showing the oil displacement effect test results of the benzimidazole-based Gemini surfactant prepared in Example 1. Detailed Embodiments

[0033] The technical solutions of the present invention will be further described below with reference to the accompanying drawings.

[0034] Example 1: A benzimidazole-based Gemini surfactant, whose chemical structural formula is as follows:

[0035]

[0036] The preparation method of the above benzimidazole-based Gemini surfactant is as follows:

[0037]

[0038] In 50 g of DMSO, 10.8 g (0.1 mol) of o-phenylenediamine and 13.2 g (0.1 mol) of cinnamaldehyde were mixed in an equimolar ratio, and 0.1 g of boric acid was used as a catalyst. The temperature was raised to 55 °C and the reaction was carried out for 5 h. Then, the solid product was precipitated by an ice-water bath to obtain styrylbenzimidazole. 22 g (0.1 mol) of styrylbenzimidazole was taken and methyl diglycidyl ether 5 g (0.05 mol) was added dropwise, and it was thoroughly mixed and stirred with 0.12 g of KOH catalyst at room temperature. First, the temperature was raised to 50 °C and the reaction was carried out for 2 h, and then the temperature was raised to 75 °C and the reaction was carried out for 3.5 h to obtain an intermediate product containing Compound III. Gaseous SO 3 was diluted to a volume ratio of 10% to obtain a mixed gas. According to the molar ratio of SO 3 to Compound III of 2:1, the mixed gas was introduced into the intermediate product containing Compound III, and the temperature was controlled at 45 °C and the reaction was carried out for 3 hours to sulfonate the benzimidazolyl diol intermediate synthesized in the previous step to obtain an intermediate product containing Compound II. After the reaction was completed, the pH of the intermediate product containing Compound II was adjusted to neutral with 30% aqueous sodium hydroxide solution. After the product was dried, it was recrystallized from acetone to obtain a light yellow solid, which was the benzimidazolyl Gemini surfactant BG 1 .

[0039] Preparation method of oil displacement agent: The benzimidazolyl Gemini surfactant prepared above was dissolved in water to prepare a 1% solution, and it was fully stirred to completely dissolve it to prepare the oil displacement agent.

[0040] Example 2: A benzimidazolyl Gemini surfactant, whose chemical structural formula is as follows:

[0041]

[0042] In 50 g of DMF, 0.2 mol of o-phenylenediamine and 0.1 mol of cinnamaldehyde were mixed, and 0.1 g of boric acid was used as a catalyst. The temperature was raised to 40 °C and the reaction was carried out for 8 h. Then, the solid product was precipitated by an ice-water bath to obtain styrylbenzimidazole. 22 g (0.1 mol) of styrylbenzimidazole was taken and ethyl diglycidyl ether 5.7 g (0.05 mol) was added dropwise, and it was thoroughly mixed and stirred with 0.12 g of KOH catalyst at room temperature. First, the temperature was raised to 60 °C and the reaction was carried out for 1 h, and then the temperature was raised to 120 °C and the reaction was carried out for 1 h to obtain an intermediate product containing Compound III. Gaseous SO 3 was diluted to a volume ratio of 10% to obtain a mixed gas. According to the molar ratio of SO 3The mixed gas was introduced into the intermediate product containing Compound III at a molar ratio of 2:1 with Compound III, and the temperature was controlled at 55 °C for reaction for 1 hour to sulfonate the benzimidazolyl diol intermediate synthesized in the previous step to obtain an intermediate product containing Compound II. After the reaction was completed, the pH of the intermediate product containing Compound II was adjusted to neutral with 30% aqueous sodium hydroxide solution. After drying the product, it was recrystallized with acetone to obtain a pale yellow solid, which was the benzimidazolyl Gemini surfactant BG 2 。

[0043] Example 3: A benzimidazolyl Gemini surfactant, whose chemical structural formula is as follows:

[0044]

[0045] In 50 g of methanol, 0.1 mol of o-phenylenediamine and 0.2 mol of cinnamaldehyde were mixed, and 0.1 g of boric acid was used as a catalyst. The temperature was raised to 80 °C and reacted for 2 h, and then the solid product was precipitated by ice-water bath to obtain styrylbenzimidazole. Take 22 g (0.1 mol) of styrylbenzimidazole, and gradually add 6.4 g (0.05 mol) of propyl diglycidyl ether dropwise. It was fully mixed and stirred with 0.12 g of KOH catalyst at room temperature. First, the temperature was raised to 30 °C and reacted for 4 h, and then the temperature was raised to 60 °C and reacted for 6 h to obtain an intermediate product containing Compound III. The gaseous SO 3 was diluted to a volume ratio of 10% to obtain a mixed gas. According to the molar ratio of SO 3 to Compound III of 2:1, the mixed gas was introduced into the intermediate product containing Compound III, and the temperature was controlled at 35 °C for reaction for 3 hours to sulfonate the benzimidazolyl diol intermediate synthesized in the previous step to obtain an intermediate product containing Compound II. After the reaction was completed, the pH of the intermediate product containing Compound II was adjusted to neutral with 30% aqueous KOH solution. After drying the product, it was recrystallized with acetone to obtain a pale yellow solid, which was the benzimidazolyl Gemini surfactant BG 3 。

[0046] In order to detect the performance of the benzimidazolyl Gemini surfactant in the present invention, the following experiments were carried out:

[0047] 1. The surface activity of the benzimidazolyl Gemini surfactants (BG 1 , BG 2 , BG 3 ) prepared in Examples 1-3 was tested. The surface tension at different concentrations was measured using a JK99M6 full-automatic surface tension meter, and the surface tension of solutions at different concentrations was tested by the hanging plate method (Pt, width 24 mm). Each sample was measured three times and the average value was taken. The results are as Figure 1As shown, it can be seen from the figure that the system has good surface activity. As the concentration increases, the surface tension decreases and the surface activity increases. Among them, BG 1 exhibits relatively excellent surface activity.

[0048] 2. Conduct an interfacial activity test on the benzimidazole-based Gemini surfactant (BG 1 ) prepared in Example 1. Use a CNG Series Spinning Drop Tensiometer (CNG Enterprise Limited, USA) to measure the oil-water interfacial tension. Place a crude oil drop in the BG aqueous solution at different concentrations. The temperature is kept constant at 50 °C and the rotation speed is 6000 r / min. Test and record the interfacial tension values. The results are as Figure 2 shown. It can be seen from the figure that as the concentration of BG 1 increases, the oil-water interfacial tension decreases and the interfacial activity increases, indicating that BG 1 has relatively excellent interfacial activity.

[0049] 3. Conduct a shear recovery performance test on the benzimidazole-based Gemini surfactant (BG 1 ) prepared in Example 1. Use an Anton Paar MCR 302 advanced rheometer. The shear rate scanning range is 1 s -1 -170 s -1 -1 s -1 . The results are as Figure 3 shown. It can be seen from the figure that as the shear rate increases, the viscosity of BG 1 decreases slightly. When the shear speed returns to 1 s -1 , its viscosity shows an obvious recovery, indicating that BG 1 has excellent shear recovery and good structural stability.

[0050] 4. Conduct a wetting performance test on the benzimidazole-based Gemini surfactant (BG 1 ) prepared in Example 1. Use a Drop Shape Analyzer-DSA30 (KRüSS GmbH, Germany) to measure the contact angle. Measure the contact angle of the BG 1 solution on the oil-wet rock surface. Fix the liquid drop volume at 3 μl and measure the influence of the concentration on its contact angle. The results are as Figure 4 shown. It can be seen from the figure that as the concentration of the BG 1 solution increases, the contact angle with the oil-wet core slice surface becomes smaller, indicating that BG 1 has good wettability, which helps it better cover the rock surface, mix with petroleum, reduce friction, and improve the recovery rate.

[0051] 5. Perform a microscopic simulation displacement experiment on the benzimidazole-based Gemini surfactant (BG 1 ) prepared in Example 1. Conduct a microscopic visualization experiment using a flat glass etching model (2×2 cm) to study the oil-water distribution in the core when BG 1 solution is used for oil displacement. The average pore diameter is 20 μm. Use a micro pump to inject the liquid at a constant speed of 0.003 mL / min. Select the traditional surfactant sodium dodecyl sulfate at the same concentration for comparison. The results are as Figure 5 shown. Compared with sodium dodecyl sulfate at the same concentration, the oil saturation in the microscopic model decreases significantly and the residual oil decreases significantly after injecting BG 1 solution, indicating that BG 1 displacement can further improve the oil recovery rate and has a better oil displacement effect.

[0052] Comparative Example 1: Use the styrylbenzimidazole prepared in Example 1 as the surfactant sample for subsequent comparative tests.

[0053] Comparative Example 2: The rest are the same as in Example 1, except that:

[0054] Replace methyldiethylene oxide with:

[0055]

[0056] The resulting end product is:

[0057]

[0058] Comparative Example 3: The rest are the same as in Example 1, except that:

[0059] Replace styrylbenzimidazole with benzimidazole.

[0060] The resulting end product is:

[0061]

[0062] Test the interfacial activity and wettability of the surfactant samples prepared in Examples 1-3 and Comparative Examples 1-3 at a working concentration of 0.8% according to the above method. The results are as follows:

[0063] Table 1 Test results of interfacial activity and wettability of different surfactants

[0064] Group <![CDATA[Interfacial tension between oil and water (mN·m -1 )]]> Contact Angle (°) Example 1 0.38 16.4±2.8 Example 2 0.36 16.1±2.2 Example 3 0.39 17.2±3.1 Comparative Example 1 0.62 32.5±5.3 Comparative Example 2 0.51 24.8±3.5 Comparative Example 3 0.47 21.7±2.1

[0065] In the results of Table 1, the oil-water interfacial tension and contact angle of the surfactant samples in Comparative Examples 1-3 were significantly higher than those in Example 1. It can be seen that the oil displacement effect of Comparative Examples 1-3 was significantly inferior to that of Example 1. From Comparative Example 1, it can be seen that the oil displacement effect of styrylbenzimidazole single molecules was not good, and a symmetric gemini structure needed to be formed by styrylbenzimidazole single molecules to produce excellent oil displacement effect. From Comparative Example 2, it can be seen that the length of the straight-chain alkyl group used to connect two styrylbenzimidazole single molecules should not be too long, and too long a straight-chain alkyl group would also lead to a decrease in the oil displacement performance of the surfactant. From Comparative Example 3, it can be seen that the generation of the excellent oil displacement effect of the present invention also depends on the participation of styryl groups. When the styryl group is absent or replaced, the overall oil displacement performance of the surfactant will also decrease significantly. In summary, the excellent oil displacement performance of the present invention depends on the symmetric gemini compound structure formed by benzimidazole groups, styryl groups and shorter alkyl chains, and these functional groups can cooperate to play an oil displacement role in a specific compound structure.

Claims

1. A benzimidazole-based Gemini surfactant represented by formula (I): Where R1 is a sulfonate group, X is C 1-30 alkyl.

2. The benzimidazole-based Gemini surfactant according to claim 1, characterized in that: The cation in the sulfonate group is Na + , K + NH4 + At least one of the following, wherein X is C 1-10 Straight chain alkyl.

3. The benzimidazole-based Gemini surfactant according to claim 1, characterized in that: The sulfonate group is a sodium sulfonate group, and X is one of a methyl group, an ethyl group, and a propyl group.

4. The method for preparing the benzimidazole-based Gemini surfactant according to any one of claims 1 to 3, characterized in that: The steps include: Where X is C 1-30 alkyl.

5. The method for preparing the benzimidazole-based Gemini surfactant according to claim 4, characterized in that: The alkaline catalyst includes at least one of KOH and NaOH, the sulfonating agent is selected from at least one of H2SO4, NaHSO3, and SO3, and the alkali solution is one of KOH aqueous solution, NaOH aqueous solution, and ammonia water.

6. The method for preparing the benzimidazole-based Gemini surfactant according to claim 4, characterized in that: The synthesis reaction conditions of the compound III are as follows: add compound IV dropwise to compound V, then add a base catalyst, mix at room temperature, first heat to 30-60° C. for reaction for 1-4 h, then heat to 60-120° C. for reaction for 1-6 h to obtain compound III; The synthesis reaction conditions of the compound II are as follows: the sulfonating agent and the compound III are mixed and reacted at 35-55° C. for 1-3 hours to obtain the compound II; The synthetic reaction conditions of the compound I are as follows: adding alkali solution with a concentration of 20-30% into the sulfonation reaction product until the sulfonation reaction product is neutral, thereby obtaining the compound I.

7. The method for preparing the benzimidazole-based Gemini surfactant according to claim 4, characterized in that: The preparation method of the compound V is:

8. The method for preparing the benzimidazole-based Gemini surfactant according to claim 7, characterized in that: The molar ratio of o-phenylenediamine to cinnamaldehyde is 1-2:1-2.

9. The method for preparing the benzimidazole-based Gemini surfactant according to claim 7, characterized in that: The reaction conditions are as follows: o-phenylenediamine and cinnamaldehyde are mixed in a polar solvent, boric acid is used as a catalyst, and the mixture is reacted at 40-80° C. for 2-8 hours.

10. Use of the benzimidazole-based Gemini surfactant according to any one of claims 1 to 3 in an oil-soluble viscosity reducer or oil displacement agent or in a microemulsion inner phase in tertiary oil recovery.

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