Ultrahigh-temperature-resistant amide emulsifier for high-density oil-based drilling fluid as well as preparation method and application thereof

Abstract

The invention discloses an ultrahigh-temperature-resistant amide emulsifier for high-density oil-based drilling fluid as well as a preparation method and application of the ultrahigh-temperature-resistant amide emulsifier. The preparation method of the emulsifier comprises the following steps: mixing vegetable oil fatty acid with a benzamide compound for reaction to obtain a first reaction product; mixing vegetable oil fatty acid with polybasic organic amine for reaction, and then mixing with an aromatic ester compound for reaction to obtain a second reaction product; and mixing the first reaction product with the second reaction product to obtain the catalyst. The emulsifier can be effectively adsorbed on an oil-water interface, the strength of an interface film is greatly improved, the emulsifier is good in compatibility with an oil-based drilling fluid system, and the temperature resistance, the emulsification stability and the sedimentation stability of the oil-based drilling fluid system can be improved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield drilling fluids, and particularly relates to an ultra-high temperature resistant amide emulsifier for high-density oil-based drilling fluids, a preparation method thereof, and an application thereof. Background Art

[0002] With the increasing emphasis on the development of deep and ultra-deep oil and gas resources, more and more unconventional complex formations are encountered during the drilling process. As a high-performance drilling fluid with good stability and strong inhibition, which can effectively stabilize the wellbore, oil-based drilling fluid shows unique advantages in the development of unconventional oil and gas resources. However, in the face of the challenges of high temperature and high pressure in deep and ultra-deep wells, high-density oil-based drilling fluids still have problems such as poor emulsion stability, sedimentation stability, and rheological filtration performance, and the temperature resistance needs to be further improved. As the most important treatment agent in oil-based drilling fluids, the temperature resistance of the emulsifier determines whether the oil-based drilling fluid can play its due role in formations thousands of meters underground. Therefore, the preparation of a high-temperature resistant emulsifier is of great significance for improving the performance of oil-based drilling fluids.

[0003] At present, many patent literatures have carried out research and reports on high-temperature resistant emulsifiers. For example: Chinese patent literature CN202111468647.3 discloses a high-temperature resistant solid emulsifier for oil-based drilling fluids. This emulsifier is prepared from a specific diamino compound, a dibasic acid, a fatty amine, and a substituted or unsubstituted alkyl sulfonic acid monomer. It can form an aggregated solid emulsifier through hydrogen bonding between groups and molecules. At the same time, due to the introduction of aromatic rings and sulfonic acid groups in its molecular structure, the temperature resistance can reach 200 °C, and it has good high-temperature stability, which can meet the needs of high-temperature deep wells, but it is slightly insufficient in terms of ultra-high temperature resistance. Chinese patent literature CN201711082088.6 discloses a preparation method of a high-temperature resistant emulsifier, including: mixing rosin acid and white oil and heating to 30-100 °C, stirring until fully dissolved, adding alkali and reacting at 30-100 °C for 1-4 hours, then adding an alkyl sulfonate and reacting for 1-4 hours, and cooling to obtain the high-temperature resistant emulsifier. The temperature resistance of this emulsifier can reach 200 °C, but the application situation in high-density oil-based drilling fluids is not provided. Chinese patent CN201410162602.7 discloses a solid emulsifier for oil-based drilling fluids. This emulsifier is an amide surfactant. The preparation method is: adding diethylenetriamine to an organic acid, adding a catalyst, heating to 175-185 °C, and reacting for 1-3 hours to obtain an intermediate product. Then, the reaction temperature is lowered to 90-120 °C, adding an acid anhydride, and continuing to react for 2-4 hours. After cooling to room temperature, the product is a brown solid, which is pulverized by a pulverizer to obtain a reddish-brown solid powder, that is, it has good temperature resistance, but the effect is average in the application of high-density oil-based drilling fluids.

[0004] Therefore, the existing emulsifiers mainly have problems such as the need to improve the temperature resistance and poor application effects in high-density drilling fluids, and technical breakthroughs are urgently needed. Summary of the Invention

[0005] In view of the deficiencies of the prior art, the present invention provides an ultra-high temperature resistant amide emulsifier for high-density oil-based drilling fluids, its preparation method and application. The emulsifier of the present invention can effectively adsorb at the oil-water interface, greatly improve the strength of the interfacial film, has good compatibility with the oil-based drilling fluid system, and can improve the temperature resistance, emulsification stability and sedimentation stability of the oil-based drilling fluid system.

[0006] In the first aspect of the present invention, a preparation method of an ultra-high temperature resistant amide emulsifier for high-density oil-based drilling fluids is provided, including: mixing and reacting vegetable oil fatty acids with benzamide compounds to obtain a first reaction product; mixing and reacting vegetable oil fatty acids with polyamine compounds, and then mixing and reacting with aromatic ester compounds to obtain a second reaction product; mixing the first reaction product and the second reaction product to obtain the product.

[0007] According to the specific embodiments of the present invention, in the preparation of the first reaction product, the mass ratio of vegetable oil fatty acids to benzamide compounds is 1:0.35 - 0.45, preferably 1:0.4.

[0008] According to the specific embodiments of the present invention, the vegetable oil fatty acids in the preparation of the first reaction product and the second reaction product are the same or different, and are each independently selected from one or more combinations of tall oil fatty acids, coconut oil fatty acids, tung oil fatty acids, and castor oil fatty acids.

[0009] According to the specific embodiments of the present invention, the benzamide compounds are selected from one or more combinations of benzamide, 4-methoxybenzamide, 2-ethoxybenzamide, and 3-methoxy-4-methylbenzamide.

[0010] According to the specific embodiments of the present invention, the preparation conditions of the first reaction product include: carried out under anaerobic conditions, the reaction temperature is 190 - 210 °C, and the reaction time is 7 - 9 h; preferably, the reaction temperature is 180 °C and the reaction time is 8 h.

[0011] According to the specific embodiments of the present invention, in the preparation of the second reaction product, the mass ratio of vegetable oil fatty acids to polyamine compounds and aromatic ester compounds is 1:0.15 - 0.25:0.2 - 0.3, preferably 1:0.2:0.25.

[0012] According to the specific embodiments of the present invention, the polyamine compounds are selected from one or more combinations of ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

[0013] According to the specific embodiments of the present invention, the aromatic ester compound is selected from one or a combination of more than two of methyl benzoate, ethyl benzoate, methyl phenylacetate, and ethyl phenylacetate.

[0014] According to the specific embodiments of the present invention, the preparation conditions of the second reaction product include: carried out under anaerobic conditions; the reaction temperature of vegetable oil fatty acid and polyorganic amine is 170 - 190 °C, and the reaction time is 7 - 9 h; the reaction temperature with the aromatic ester compound is 110 - 130 °C, and the reaction time is 4 - 6 h; preferably, the reaction temperature of vegetable oil fatty acid and polyorganic amine is 180 °C, and the reaction time is 8 h; the reaction temperature with the aromatic ester compound is 120 °C, and the reaction time is 5 h.

[0015] According to the specific embodiments of the present invention, the mass ratio of the first reaction product to the second reaction product is 1.0 - 1.2:1.

[0016] In the second aspect of the present invention, there is provided a high-temperature-resistant amide emulsifier for high-density oil-based drilling fluid prepared by the aforementioned preparation method.

[0017] In the third aspect of the present invention, there is provided an oil-based drilling fluid, which contains the aforementioned emulsifier; preferably, in the oil-based drilling fluid, the concentration of the emulsifier is 40 - 60 g / L.

[0018] In the fourth aspect of the present invention, there is provided the application of the aforementioned emulsifier in high-density oil-based drilling fluid; preferably, the high-density oil-based drilling fluid is an oil-based drilling fluid with a density not lower than 2.2 g / cm 3 ³.

[0019] The beneficial effects of the present invention are as follows:

[0020] In the preparation method provided by the present invention, the reaction product obtained by reacting vegetable oil fatty acid with a benzamide compound is used as the main emulsifier, and the reaction product obtained by reacting vegetable oil fatty acid with polyorganic amine and aromatic ester compound is used as the auxiliary emulsifier. Amide groups can be introduced as hydrophilic groups in both the main emulsifier and the auxiliary emulsifier, and benzene rings are introduced. The amide groups have strong hydrophilicity and high-temperature stability, and the introduced benzene rings further enhance their temperature resistance. The emulsifier obtained by compounding the main and auxiliary emulsifiers has the following characteristics: 1) It can adapt to the optimal HLB value of white oil-based oil-based drilling fluid, significantly reduce the interfacial tension at the oil-water interface, improve the strength of the interfacial film, enhance the emulsification stability of the emulsion, and resist high temperature up to 230 °C, effectively avoiding problems such as emulsion instability and a significant decrease in the demulsification voltage after high-temperature aging; 2) At a density of 2.2 g / cm 3In a high-density oil-based drilling fluid, it can increase the shear force of the drilling fluid, maintain the stable suspension of weighting materials, and has good sedimentation stability after aging; 3) It has good compatibility with other oil-based drilling fluid additives, has little influence on the viscosity of the drilling fluid, can better control the filtration loss of the drilling fluid, and maintain the stable performance of the drilling fluid. Detailed implementation mode

[0021] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described. Obviously, the described embodiments are some, but not all, of the embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0022] Example 1

[0023] An anti-super-high-temperature amide emulsifier for high-density oil-based drilling fluid is prepared as follows:

[0024] (1) Add 100 g of tall oil fatty acid into a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. After the temperature of the sample in the flask reaches 90 °C, start timing, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser in time to remove the water generated during the reaction. Slowly add 40 g of benzamide into the flask, adjust the temperature of the oil bath to 200 °C. After the benzamide is completely melted and the temperature of the sample in the flask reaches 200 °C, start timing. After 8 h, the reaction ends, and a brown viscous liquid is obtained, which is recorded as the anti-super-high-temperature main emulsifier.

[0025] (2) Add 100 g of tall oil fatty acid into a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. After the temperature of the sample in the flask reaches 90 °C, start timing, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser. Slowly add 20 g of ethylenediamine into the flask, adjust the temperature of the oil bath to 180 °C. After the temperature of the sample in the flask reaches 180 °C, start timing. After 8 h, the reaction ends. Turn off the oil bath. After the temperature of the sample drops below 70 °C, slowly add 25 g of methyl benzoate into the flask, adjust the temperature of the oil bath to 120 °C. After the temperature of the sample in the flask reaches 120 °C, start timing. After 5 h, the reaction ends, and a brown viscous liquid is obtained, which is recorded as the anti-super-high-temperature auxiliary emulsifier.

[0026] (3) Mix the anti-super-high-temperature main emulsifier and the anti-super-high-temperature auxiliary emulsifier in a mass ratio of 1:1 to obtain the product.

[0027] Example 2

[0028] An ultra-high temperature resistant amide emulsifier for high-density oil-based drilling fluid, the preparation method is as follows:

[0029] (1) Add 100 g of coconut oil fatty acid to a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. Start timing after the temperature of the sample in the flask reaches 90 °C, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser. Slowly add 40 g of 4-methoxybenzamide to the flask, adjust the temperature of the oil bath to 200 °C, start timing after the benzamide is completely melted and the temperature of the sample in the flask reaches 200 °C, and the reaction ends after 8 h to obtain a brown viscous liquid, denoted as the ultra-high temperature resistant main emulsifier.

[0030] (2) Add 100 g of coconut oil fatty acid to a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. Start timing after the temperature of the sample in the flask reaches 90 °C, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser. Slowly add 20 g of diethylenetriamine to the flask, adjust the temperature of the oil bath to 180 °C, start timing after the temperature of the sample in the flask reaches 180 °C, and the reaction ends after 8 h. Turn off the oil bath, and after the temperature of the sample drops below �0 °C, slowly add 25 g of ethyl benzoate to the flask, adjust the temperature of the oil bath to 120 °C, start timing after the temperature of the sample in the flask reaches 120 °C, and the reaction ends after 5 h to obtain a brown viscous liquid, denoted as the ultra-high temperature resistant auxiliary emulsifier.

[0031] (3) Mix the ultra-high temperature resistant main emulsifier and the ultra-high temperature resistant auxiliary emulsifier according to a mass ratio of 1.2:1 to obtain the product.

[0032] Example 3

[0033] An ultra-high temperature resistant amide emulsifier for high-density oil-based drilling fluid, the preparation method is as follows:

[0034] (1) Add 100 g of tung oil fatty acid to a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. Start timing after the temperature of the sample in the flask reaches 90 °C, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser. Slowly add 40 g of 2-ethoxybenzamide to the flask, adjust the temperature of the oil bath to 200 °C, start timing after the benzamide is completely melted and the temperature of the sample in the flask reaches 200 °C, and the reaction ends after 8 h to obtain a brown viscous liquid, denoted as the ultra-high temperature resistant main emulsifier.

[0035] (2) Add 100 g of eleostearic acid to a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. Start timing after the temperature of the sample in the flask reaches 90 °C, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser. Slowly add 20 g of triethylenetetramine to the flask, adjust the temperature of the oil bath to 180 °C, start timing after the temperature of the sample in the flask reaches 180 °C, and the reaction ends after 8 h. Turn off the oil bath. After the temperature of the sample drops below 70 °C, slowly add 25 g of methyl phenylacetate to the flask, adjust the temperature of the oil bath to 120 °C, start timing after the temperature of the sample in the flask reaches 120 °C, and the reaction ends after 5 h to obtain a brown viscous liquid, denoted as the anti-ultra-high temperature auxiliary emulsifier.

[0036] (3) Mix the anti-ultra-high temperature main emulsifier and the anti-ultra-high temperature auxiliary emulsifier in a mass ratio of 1:1 to obtain the product.

[0037] Example 4

[0038] An anti-ultra-high temperature amide emulsifier for high-density oil-based drilling fluids is prepared as follows:

[0039] (1) Add 100 g of ricinoleic acid to a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. Start timing after the temperature of the sample in the flask reaches 90 °C, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser. Slowly add 40 g of 3-methoxy-4-methylbenzamide to the flask, adjust the temperature of the oil bath to 200 °C, start timing after the benzamide completely melts and the temperature of the sample in the flask reaches 200 °C, and the reaction ends after 8 h to obtain a brown viscous liquid, denoted as the anti-ultra-high temperature main emulsifier.

[0040] (2) Add 100 g of ricinoleic acid to a flask equipped with a stirring device and a ventilation pipe. Adjust the temperature of the oil bath to 90 °C, and control the stirring rate at 350 r / min. Start timing after the temperature of the sample in the flask reaches 90 °C, and pass nitrogen for 1 h to remove oxygen. After deoxygenation, remove the ventilation pipe and install a water separator and a condenser. Slowly add 20 g of tetraethylenepentamine to the flask, adjust the temperature of the oil bath to 180 °C, start timing after the temperature of the sample in the flask reaches 180 °C, and the reaction ends after 8 h. Turn off the oil bath. After the temperature of the sample drops below 70 °C, slowly add 25 g of ethyl phenylacetate to the flask, adjust the temperature of the oil bath to 120 °C, start timing after the temperature of the sample in the flask reaches 120 °C, and the reaction ends after 5 h to obtain a brown viscous liquid, denoted as the anti-ultra-high temperature auxiliary emulsifier.

[0041] (3) Mix the anti-ultra-high temperature main emulsifier and the anti-ultra-high temperature auxiliary emulsifier in a mass ratio of 1:1 to obtain the product.

[0042] Comparative Example 1

[0043] It is different from Example 1 in that the anti-ultra-high temperature co-emulsifier is removed.

[0044] Comparative Example 2

[0045] It is different from Example 1 in that the anti-ultra-high temperature main emulsifier is removed.

[0046] Comparative Example 3

[0047] It is different from Example 1 in that the addition amount of benzamide is 50 g.

[0048] Comparative Example 4

[0049] It is different from Example 1 in that the addition amount of ethylenediamine is 30 g.

[0050] Comparative Example 5

[0051] It is different from Example 1 in that the addition amount of methyl benzoate is 35 g.

[0052] 1. Evaluation of Emulsion Stability Performance

[0053] Preparation of emulsion: Measure 270 mL of white oil and pour it into a slurry cup. Add 7.5 g of the main emulsifiers prepared in each example and comparative example and 7.5 g of co-emulsifiers to the slurry cup respectively. For the emulsifiers prepared in Comparative Example 1 and Comparative Example 2, directly weigh 15 g and add them to the slurry cup. Use a high-speed stirrer to stir at a speed of 10000±100 r / min for 20 min to completely disperse the emulsifiers. Then add 30 mL of 30% CaCl2 brine with a mass fraction to the slurry cup and stir at a high speed for another 20 min. Use an electric stability measuring instrument to measure the demulsification voltage of the emulsion, and use a real-time particle size and particle number analyzer to measure the average particle size of the emulsion at the initial moment and after 16 h.

[0054] Transfer the above emulsion to an aging tank and continuously age it at 230°C for 16 h using a roller heating furnace. After aging, stir the emulsion cooled to room temperature at a high speed for another 20 min, and measure its demulsification voltage after aging and the average particle size of the emulsion at the initial moment and after 16 h after aging. The experimental results are shown in Table 1.

[0055] Table 1 Evaluation of Emulsion Stability Performance

[0056]

[0057]

[0058] As can be seen from Table 1, the emulsifiers prepared in the examples all have good emulsifying stability and temperature resistance. After aging, the demulsification voltage can be maintained above 500V, and the emulsion particle size is relatively small. In Comparative Example 1 and Comparative Example 2, only a single emulsifier was used to stabilize the emulsion, and its HLB value could not reach the optimal range for stabilizing the white oil-based emulsion. Therefore, its emulsifying stability is slightly poor, and the particle size of the formed emulsion is relatively large. In Comparative Example 3, an excessive amount of benzamide was added during the preparation of the main emulsifier. In Comparative Example 4, an excessive amount of ethylenediamine was added during the preparation of the auxiliary emulsifier. In Comparative Example 5, an excessive amount of methyl benzoate was added during the preparation of the auxiliary emulsifier, all of which led to a slight increase in the hydrophilicity of the finally prepared emulsifier, resulting in a slight decrease in the emulsifying effect compared with the examples, but still better than the emulsifiers of Comparative Example 1 and Comparative Example 2.

[0059] 2. Performance evaluation of oil-based drilling fluid system

[0060] Preparation of oil-based drilling fluid system: Measure 270 mL of white oil and pour it into a slurry cup. Add 7.5 g of the main emulsifiers prepared in each example and comparative example and 7.5 g of the auxiliary emulsifier to the slurry cup respectively. For the emulsifiers prepared in Comparative Example 1 and Comparative Example 2, directly weigh 15 g and add them to the slurry cup. Use a high-speed stirrer to stir at a speed of 10,000 ± 100 r / min for 20 min to completely disperse the emulsifier. Then add 30 mL of 30% mass fraction CaCl2 brine to the slurry cup and stir at high speed for another 20 min. Add 12 g of organophilic clay, 15 g of calcium oxide, 9 g of oxidized asphalt, 9 g of organic lignite, 1.5 g of thixotropic agent, barite powder (to increase the density of the drilling fluid to 2.2 g / cm 3 ) and 1% of the wetting agent based on the mass of barite powder to the emulsion in sequence. After each additive is added, it is necessary to stir at high speed for 20 min.

[0061] Use a six-speed rotational viscometer to measure the viscosity and shear force of the oil-based drilling fluid system at 65 °C, and use an electrical stability measuring instrument to measure the demulsification voltage of the drilling fluid at 65 °C. Transfer the above drilling fluid to an aging tank and use a roller heating furnace to age it continuously at 230 °C for ɪ6 h. After aging, stir the drilling fluid cooled to room temperature at high speed for another 20 min, and measure its viscosity, shear force, and demulsification voltage after aging, and measure its high-temperature and high-pressure filtration loss at 200 °C × 3.5 MPa. The experimental results are shown in Table 2.

[0062] Table 2 Basic performance evaluation of oil-based drilling fluid

[0063]

[0064]

[0065] As can be seen from Table 2, the emulsifiers prepared in the examples have good compatibility in the drilling fluid system. After aging, the demulsification voltage and shear force are maintained at a relatively high level, and the high-temperature and high-pressure filtration loss is controlled within 5 mL. In Comparative Example 1 and Comparative Example 2, only a single emulsifier is used to stabilize the emulsion, and the demulsification voltage is quite different from that of each example using a composite emulsifier. At the same time, its shear force is slightly lower and the filtration loss also increases. The hydrophilicity of the emulsifiers prepared in Comparative Examples 3, 4, and 5 is slightly increased. Therefore, the performance of the drilling fluid system formulated with them is slightly worse than that of the examples, but still better than the emulsifiers of Comparative Example 1 and Comparative Example 2.

[0066] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited to the specific details in the above embodiments. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, and these simple modifications all belong to the protection scope of the present invention.

Claims

1. A preparation method of an amide emulsifier for high-density oil-based drilling fluid with ultra-high temperature resistance, characterized in that, The preparation method includes: Mixing and reacting vegetable oil fatty acid with a benzamide compound to obtain a first reaction product; Mixing and reacting vegetable oil fatty acid with a polyorganic amine, and then mixing and reacting with an aromatic ester compound to obtain a second reaction product; Mixing the first reaction product and the second reaction product to obtain the product.

2. The preparation method according to claim 1, characterized in that, In the preparation of the first reaction product, the mass ratio of vegetable oil fatty acid to the benzamide compound is 1:0.35 - 0.45, preferably 1:0.

4.

3. The preparation method according to claim 1, wherein, The vegetable oil fatty acids in the preparation of the first reaction product and the second reaction product are the same or different, and each independently selected from one or more combinations of tall oil fatty acid, coconut oil fatty acid, tung oil fatty acid, and castor oil fatty acid.

4. The preparation method according to claim 1, characterized in that, The benzamide compound is selected from one or more combinations of benzamide, 4-methoxybenzamide, 2-ethoxybenzamide, and 3-methoxy-4-methylbenzamide.

5. The preparation method according to claim 1, characterized in that, The preparation conditions of the first reaction product include: carried out under anaerobic conditions, the reaction temperature is 190 - 210 °C, and the reaction time is 7 - 9 h; preferably, the reaction temperature is 180 °C and the reaction time is 8 h.

6. The preparation method according to claim 1, characterized in that, In the preparation of the second reaction product, the mass ratio of vegetable oil fatty acid to polyorganic amine and aromatic ester compound is 1:0.15 - 0.25:0.2 - 0.3, preferably 1:0.2:0.

25.

7. The preparation method according to claim 1, characterized in that, The polyorganic amine is selected from one or more combinations of ethylenediamine, diethylenetriamine, triethylenetetramine, and tetraethylenepentamine.

8. The preparation method according to claim 1, characterized in that, The aromatic ester compound is selected from one or more combinations of methyl benzoate, ethyl benzoate, methyl phenylacetate, and ethyl phenylacetate.

9. The preparation method according to claim 1, wherein The preparation conditions of the second reaction product include: carried out under anaerobic conditions; the reaction temperature of the vegetable oil fatty acid and the polyorganic amine is 170 - 190 °C, and the reaction time is 7 - 9 h; the reaction temperature with the aromatic ester compound is 110 - 130 °C, and the reaction time is 4 - 6 h; Preferably, the reaction temperature of the vegetable oil fatty acid and the polyorganic amine is 180 °C, and the reaction time is 8 h; the reaction temperature with the aromatic ester compound is 120 °C, and the reaction time is 5 h.

10. The preparation method according to claim 1, characterized in that, The mass ratio of the first reaction product to the second reaction product is 1.0 - 1.2:

1.

11. The ultra-high temperature resistant amide emulsifier for high-density oil-based drilling fluid prepared by the preparation method according to any one of claims 1 to 10.

12. An oil-based drilling fluid, characterized in that, The oil-based drilling fluid contains the emulsifier according to claim 11.

13. The oil-based drilling fluid according to claim 12, characterized in that, In the oil-based drilling fluid, the concentration of the emulsifier is 40 - 60 g / L.

14. The application of the emulsifier according to claim 11 in high-density oil-based drilling fluid.

15. The application according to claim 14, characterized in that The high-density oil-based drilling fluid described above has a density of not less than 2.2 g / cm 3 oil-based drilling fluid.

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