Fluorine-containing polyether demulsifier, and preparation method and application thereof

Abstract

The application discloses a fluorine-containing polyether demulsifier and a preparation method and application thereof, and belongs to the technical field of oil field chemicals. The demulsifier has a structure as shown in the formula (I): formula (I); wherein a represents an integer of 5-20, n represents an integer of 80-200, and m represents an integer of 50-130. The demulsifier has the characteristics of high molecular weight, high dehydration rate and fast dehydration speed. In particular, the demulsifier has wide temperature adaptability and can maintain high-efficiency demulsification performance in the range of 30-85 DEG C.

Description

Technical Field

[0001] This application relates to a fluorinated polyether demulsifier, its preparation method and application, belonging to the technical field of oilfield chemical agents. Background Technology

[0002] As oilfields are developed, the extracted crude oil emulsions become increasingly stable. Asphaltenes, gums, petroleum acids, and wax crystals in crude oil are naturally occurring, highly reactive interfacial components that together form a high-strength, highly viscoelastic interfacial film, which is the internal factor contributing to emulsion stability. Tertiary oil recovery (polymer flooding, surfactant flooding, and ternary composite flooding) introduces chemical agents to enhance oil recovery. These agents, combined with natural emulsifiers, push the emulsion towards a more stable state, which is the external factor contributing to emulsion stability. Existing demulsifiers mainly include polyethers, cationic surfactants, and silicone-containing agents, but when dealing with complex crude oil emulsions, they generally suffer from low demulsification efficiency, slow dehydration speed, and insufficient temperature resistance.

[0003] Chinese invention patent application CN112876664A discloses a polyether ester crude oil demulsifier and its preparation method. The raw material composition includes: 0.3-0.5g each of two or more ethylene glycol condensates, 8.5-12.8g each of two or more polypropylene glycols of different molecular weights, 0.3-0.55g of chain extender, 0.1-0.35g of catalyst, and 0.03-0.85g of polyethylenepolyamine. This demulsifier exhibits good demulsification performance on crude oil emulsions. However, this demulsifier requires 45℃ to achieve a good demulsification effect; its demulsification effect at lower and higher temperatures is unknown, making it difficult to adapt to the temperature variations of different operating conditions in oilfields. Summary of the Invention

[0004] The purpose of this invention is to provide a fluorinated polyether demulsifier, its preparation method and application, which has the characteristics of high molecular weight, high dehydration rate and fast dehydration speed. In particular, the demulsifier of this invention has wide temperature adaptability and can maintain high efficiency demulsification performance in the range of 30-85℃.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: According to one aspect of this application, a fluorinated polyether demulsifier is provided, having a structure as shown in formula (I): Formula (I); Where a represents an integer from 5 to 20, n represents an integer from 80 to 200, and m represents an integer from 50 to 130.

[0006] Optionally, the molecular weight of the fluorinated polyether demulsifier is 10,000-30,000.

[0007] According to another aspect of this application, a method for preparing a fluorinated polyether demulsifier as described in any one of the above claims is provided, comprising: (1) Add allyl glycidyl ether, 2,2,3,4,4,4-hexafluorobutyl methacrylate and aromatic solvent to a flask, stir and heat to 110-130℃, add 1 part of initiator, maintain the temperature at 120-130℃ for reaction, add 1 part of initiator every 0.5-1.5h, add a total of 5 parts, and then continue to keep the reaction at 120-130℃ for 1-3h to form a polymer solution; (2) Add the polymer solution and catalyst formed in step (1) into the reactor, remove oxygen by nitrogen replacement, and introduce propylene oxide at 120-130℃ for stirring reaction. After the reaction is completed, remove solvent and impurities under vacuum, purify, and form polymer polyether head. (3) Add the polymer polyether head and catalyst formed in step (2) into the reactor, replace the oxygen with nitrogen, and introduce propylene oxide at 120-130℃ for stirring reaction. After the reaction is completed, age for 0.5-1.5h, then introduce ethylene oxide at 120-130℃ for stirring reaction. After the reaction is completed, age for 0.5-1.5h to obtain fluorinated polyether demulsifier.

[0008] Optionally, in step (1), the aromatic solvent is toluene and / or xylene; And / or, the initiator is selected from any one of di-tert-butyl peroxide, tert-butyl peroxide, and dicumyl peroxide.

[0009] Optionally, in step (1), the mass ratio of allyl glycidyl ether to 2,2,3,4,4,4-hexafluorobutyl methacrylate is 1:(2.0-2.5). And / or, the mass ratio of the aromatic solvent to the total mass of the polymerizing monomer is 1:(2.0-3.0). And / or, the initiator accounts for 0.3-1 wt% of the total mass of the polymerizing monomers.

[0010] Optionally, in steps (2) and (3), the catalyst is selected from any one of potassium hydroxide, potassium methoxide, potassium ethoxide and DMC bimetallic catalyst.

[0011] Optionally, in step (2), the mass ratio of the polymer solution to propylene oxide is 1:(2-2.6). And / or, the amount of the catalyst is 0.3-1 wt% of the mass of propylene oxide.

[0012] Optionally, in step (3), the mass ratio of the polymer polyether head, propylene oxide and ethylene oxide is 1:(10-30):(5-15).

[0013] And / or, the amount of the catalyst is 0.2-0.8 wt% of the total mass of propylene oxide and ethylene oxide.

[0014] According to another aspect of this application, the application of any of the fluorinated polyether demulsifiers described above in the demulsification and dehydration process of produced crude oil is provided.

[0015] Optionally, the amount of the fluorinated polyether demulsifier is 90-110 ppm.

[0016] The beneficial effects of this application include, but are not limited to: 1. The fluorinated polyether demulsifier of this application uses allyl glycidyl ether (AGE) as a bifunctional monomer, possessing both carbon-carbon double bonds and epoxy groups. The double bonds can participate in free radical polymerization, and the epoxy groups can serve as ring-opening polymerization sites. The fluorinated alkyl chain of 2,2,3,4,4,4-hexafluorobutyl methacrylate (HFBMA) endows the molecule with strong hydrophobicity and interfacial penetration ability. After copolymerizing AGE and HFBMA, the ring-opening polymerization of propylene oxide (PO) / ethylene oxide (EO) is initiated by utilizing the residual epoxy groups in the main chain. The resulting fluorinated polyether demulsifier has a high molecular weight, and the polymer chain has stronger interfacial activity, enabling it to be rapidly adsorbed at the oil-water interface, replacing natural emulsifiers and achieving highly efficient demulsification.

[0017] 2. The fluorinated polyether demulsifier of this application, due to the introduction of fluorinated alkyl segments, possesses extremely low surface free energy. These fluorinated segments can spontaneously spread at the oil-water interface, effectively displacing the rigid interfacial film formed by natural emulsifiers (such as gums, asphaltenes, and naphthenic acid soaps) in crude oil. The carbon-fluorine bond (CF) has a bond energy as high as 485 kJ / mol, higher than the carbon-hydrogen bond (CH, 413 kJ / mol). Therefore, this fluorinated polyether demulsifier is not prone to thermal degradation or chain breakage under high-temperature conditions (≥80℃). Simultaneously, the low surface energy characteristics of the fluorinated segments remain stable at high temperatures and will not desorb due to temperature increases. The polyether side chains can be adjusted in structure at different temperatures by controlling the PO / EO ratio, maintaining interfacial activity. Experimental results show that the demulsifier of this invention maintains high-efficiency demulsification within the temperature range of 30-85℃, overcoming the limitations of conventional polyether demulsifiers that fail at high temperatures due to cloud point effects and become inactive at low temperatures due to crystallization.

[0018] 3. The fluorinated polyether demulsifier of this application can precisely control the content of fluorinated segments by adjusting the molar ratio of AGE to HFBMA, thereby regulating the hydrophobic strength and interfacial adsorption energy of the demulsifier; by limiting the mass ratio of PO to EO, the hydrophilic-lipophilic balance value (HLB value) suitable for crude oil emulsion can be precisely controlled to avoid the reduction of interfacial activity due to HLB value imbalance.

[0019] 4. The preparation method of the fluorinated polyether demulsifier of this application is simple, the raw materials are readily available, and it is easy to carry out industrial production; the prepared demulsifier has a high demulsification rate, fast dehydration speed, and long-lasting demulsification effect, and is widely used in the treatment of oilfield produced fluids. Attached Figure Description

[0020] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings: Figure 1 This is a diagram of fluorinated polyether demulsifier 1#GPC from Example 1 of this application.

[0021] Figure 2 The infrared spectrum of fluorinated polyether demulsifier 1# in Example 1 of this application is shown. Detailed Implementation

[0022] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

[0023] Unless otherwise specified in the examples, the procedures shall be performed under standard conditions or conditions recommended by the manufacturer. Raw materials or instruments whose manufacturers are not specified are all commercially available products.

[0024] Example 1 A method for using a fluorinated polyether demulsifier includes: (1) 100g allyl glycidyl ether, 220g 2,2,3,4,4,4-hexafluorobutyl methacrylate, and 125g xylene were added to a flask and stirred until the temperature reached 120°C. 0.2g di-tert-butyl peroxide was added, and the reaction was maintained at 125°C. During the reaction, 0.2g di-tert-butyl peroxide was added every 1 hour for a total of 5 times. After the addition was completed, the reaction was maintained at 125°C for 2 hours to form a polymer solution. The reaction equation is as follows:

[0025] (2) Add 100g of the polymer solution formed in step (1) and 1.1g of potassium hydroxide to a high-temperature and high-pressure polymerization reactor. Remove oxygen by nitrogen purging, stir and heat, and introduce 215g of propylene oxide at 125℃. After the reaction is complete, remove the solvent and impurities under vacuum, purify, and form a polymer polyether head. The reaction equation is as follows:

[0026] (3) Add 10g of the polymer polyether head formed in step (2) and 1.2g of potassium hydroxide to a high-temperature and high-pressure polymerization reactor. Remove oxygen by nitrogen purging, stir and heat, and continue to introduce 200g of propylene oxide at 125℃. After the reaction is complete, age for 1 hour, and continue to introduce 100g of ethylene oxide at 125℃ for 1 hour to obtain fluorinated polyether demulsifier 1# with a molecular weight of 21217. The reaction equation is as follows: .

[0027] Example 2 A method for using a fluorinated polyether demulsifier (the reaction equations involved in each step are the same as in Example 1), comprising: (1) 100g allyl glycidyl ether, 220g 2,2,3,4,4,4-hexafluorobutyl methacrylate and 125g toluene were added to a flask, stirred and heated to 120°C, and 0.4g tert-butyl peroxide was added. The temperature was maintained at 125°C for the reaction. 0.4g tert-butyl peroxide was added every 1 hour during the reaction, for a total of 5 times. After the addition was completed, the reaction was continued at 125°C for 2 hours to form a polymer solution. (2) Add 100g of the polymer solution formed in step (1) and 1.3g of potassium methoxide to a high-temperature and high-pressure polymerization reactor, remove oxygen by nitrogen replacement, stir and heat, and introduce 215g of propylene oxide at 125℃. After the reaction is complete, remove the solvent and impurities under vacuum, purify, and form a polymer polyether head. (3) Add 10g of the polymer polyether head formed in step (2) and 0.75g of potassium methoxide to a high-temperature and high-pressure polymerization reactor, remove oxygen by nitrogen replacement, stir and heat up, and continue to introduce 100g of propylene oxide at 125°C. After the reaction is complete, age for 1 hour, and continue to introduce 50g of ethylene oxide at 125°C for 1 hour to obtain fluorinated polyether demulsifier 2# with a molecular weight of 10951.

[0028] Example 3 A method for using a fluorinated polyether demulsifier (the reaction equations involved in each step are the same as in Example 1), comprising: (1) 100g allyl glycidyl ether, 250g 2,2,3,4,4,4-hexafluorobutyl methacrylate and 117g toluene were added to a flask, stirred and heated to 120°C, and 0.7g dicumyl peroxide was added. The temperature was maintained at 125°C for the reaction. 0.7g dicumyl peroxide was added every 1 hour during the reaction, for a total of 5 times. After the addition was completed, the reaction was continued at 125°C for 2 hours to form a polymer solution. (2) Add 100g of the polymer solution formed in step (1) and 2.6g of potassium ethoxide to a high-temperature and high-pressure polymerization reactor, remove oxygen by nitrogen replacement, stir and heat up, and introduce 260g of propylene oxide at 125℃. After the reaction is complete, remove the solvent and impurities under vacuum, purify, and form a polymer polyether head. (3) Add 10g of the polymer polyether head and 3.6g of potassium ethoxide formed in step (2) into a high-temperature and high-pressure polymerization reactor, remove oxygen by nitrogen replacement, stir and heat up, and continue to introduce 300g of propylene oxide at 125°C. After the reaction is completed, age for 1 hour, and continue to introduce 150g of ethylene oxide at 125°C for 1 hour to obtain fluorinated polyether demulsifier 3# with a molecular weight of 28148.

[0029] Example 4 A method for using a fluorinated polyether demulsifier (the reaction equations involved in each step are the same as in Example 1), comprising: (1) Add 100g allyl glycidyl ether, 200g 2,2,3,4,4,4-hexafluorobutyl methacrylate and 150g xylene to a flask, stir and heat to 120℃, add 0.2g di-tert-butyl peroxide, maintain the temperature at 125℃ and react. Add 0.2g di-tert-butyl peroxide every 1h during the reaction, for a total of 5 times. After the addition is complete, continue to react at 125℃ for 2h to form a polymer solution. (2) Add 100g of the polymer solution formed in step (1) and 0.6g of DMC bimetallic catalyst into a high-temperature and high-pressure polymerization reactor, remove oxygen by nitrogen replacement, stir and heat up, and introduce 200g of propylene oxide at 125℃. After the reaction is completed, remove the solvent and impurities under vacuum, purify, and form a polymer polyether head. (3) Add 10g of the polymer polyether head formed in step (2) and 0.54g of DMC bimetallic catalyst to a high-temperature and high-pressure polymerization reactor, remove oxygen by nitrogen replacement, stir and heat up, and continue to introduce 200g of propylene oxide at 125℃. After the reaction is completed, age for 1h, and continue to introduce 70g of ethylene oxide at 125℃ for 1h of aging to obtain fluorinated polyether demulsifier 4# with a molecular weight of 19892.

[0030] Comparative Example 1 The difference from Example 1 is that the polymer solution synthesized in step (1) is replaced with propylene glycol.

[0031] Comparative Example 2 The difference from Example 1 is that the polymer solution synthesized in step (1) is replaced with tetraethylenepentamine.

[0032] Comparative Example 3 The difference from Example 1 is that in step (3), the mass of propylene oxide introduced is 80g and the mass of ethylene oxide introduced is 200g.

[0033] Comparative Example 4 The difference from Example 1 is that allyl glycidyl ether is replaced with glycidyl methacrylate.

[0034] Comparative Example 5 The difference from Example 1 is that 2,2,3,4,4,4-hexafluorobutyl methacrylate is replaced with n-butyl methacrylate.

[0035] Comparative Example 6 The difference from Example 1 is that step (1) is: 100g allyl glycidyl ether, 220g 2,2,3,4,4,4-hexafluorobutyl methacrylate, and 125g xylene were added to a flask, stirred and heated to 120℃, and 1.0g di-tert-butyl peroxide was added. The temperature was maintained at 125℃ for 5 hours to form a polymer solution.

[0036] Test Example 1: Crude oil demulsification experiment at a joint station in Shengli Oilfield Experiments were conducted on produced fluid samples from a joint station in Shengli Oilfield. The demulsification performance of each reagent group was tested under the same temperature and dosage conditions. The demulsifiers obtained in Examples 1-4 are designated as 1#, 2#, 3#, and 4#. The field demulsifier composition was phenolic resin polyoxypropylene polyoxyethylene ether. The field oil sample had a water content of 42%, a dehydration temperature of 60℃, and a test volume of 80 mL. The test results for each reagent are shown in Table 1. Table 1 Dehydration data of demulsifier

[0037] As shown in Table 1, the demulsifiers 1#-4# provided in Examples 1-4 have a high dehydration rate, all reaching over 90%. Among them, demulsifier 1# has the best effect, with a dehydration rate of 96.7%.

[0038] Based on the differences in performance between Comparative Examples 1, 2, and 1, it is evident that the polyether head prepared from the polymer solution obtained by copolymerizing allyl glycidyl ether with 2,2,3,4,4,4-hexafluorobutyl methacrylate is the core structure for achieving efficient demulsification in the fluorinated polyether demulsifier of this application. When replaced with conventional polyether initiators such as propylene glycol and polyethylene polyamine, the dehydration rate and dehydration percentage of the demulsifier both decreased significantly, with dehydration percentages of only 65.5% and 75.9%, respectively, far lower than the 96.7% in Example 1. This indicates that the fluorinated copolymer polymer segments can endow the demulsifier with excellent interfacial adsorption and film disruption capabilities, which is the key to its demulsification performance being far superior to that of traditional polyether demulsifier initiation systems.

[0039] Based on the difference in effects between Comparative Example 3 and Example 1, it can be seen that the ratio of propylene oxide to ethylene oxide has a significant impact on the demulsifying performance of the demulsifier in this application. When the amount of propylene oxide introduced is greatly reduced and the amount of ethylene oxide introduced is greatly increased, the dehydration start-up speed of the demulsifier is extremely slow, the initial dehydration rate is almost 0, and the final dehydration rate is only 58.0%, which is much lower than that of Example 1. This indicates that only within the mass ratio range of polymer polyether head, propylene oxide, and ethylene oxide specified in this application can a demulsifier with a suitable HLB value be obtained. Deviating from this ratio will lead to a significant reduction in the interfacial activity of the demulsifier, making it impossible to effectively achieve oil-water separation.

[0040] Based on the difference in effects between Comparative Example 4 and Example 1, it can be seen that the allyl flexible side chain structure exhibits strong molecular chain stretching after polymerization, resulting in excellent film formation and interface compatibility; the methacrylate rigid group accounts for a high proportion, the polymer product molecules are relatively rigid, and the deformation and wetting ability are relatively weak, showing a low dehydration rate.

[0041] Based on the difference in effects between Comparative Example 5 and Example 1, it can be seen that the demulsifier with fluorine-containing structure, due to its ultra-high surface activity, is superior to the traditional non-fluorine polyether demulsifier in terms of demulsification speed and final dehydration rate.

[0042] The difference in effects between Comparative Example 6 and Example 1 indicates that Comparative Example 6, by adding the initiator all at once, resulted in an excessively high concentration of free radicals in the initial stage of the reaction, leading to an excessively fast polymerization rate, localized overheating, and explosive polymerization. This resulted in an uneven reaction system, affecting the structural regularity and density of the polymer, and consequently making it difficult to effectively remove water during the subsequent dehydration process, resulting in a low dehydration rate. In contrast, Example 1, by adding the initiator in batches, effectively controlled the rate of free radical generation, allowing the polymerization reaction to proceed smoothly, resulting in a more uniform temperature distribution in the system, enhanced controllability of the polymerization process, and a more homogeneous polymer structure, thus exhibiting a higher dehydration rate.

[0043] Test Example 2: Low-Temperature Demulsification Test of Demulsifier Experiments were conducted on produced fluid samples from a joint station in Shengli Oilfield. The water content of the samples was 42%, the dehydration temperature was 30℃, and the test volume was 80 mL. The test results for each reagent are shown in Table 2. Table 2 Dehydration data for demulsifiers

[0044] As shown in Table 2, the demulsifiers 1#-4# provided in Examples 1-4 still have a high dehydration rate at a low temperature of 30℃, indicating that the products in the examples are suitable for low temperature demulsification at 30℃. However, in the field, when the demulsification temperature is reduced from 60℃ to 30℃, the demulsification rate drops from 92.3% to 50.6%, and the demulsification effect decreases significantly. The demulsifiers provided in Comparative Examples 1-6 all have low dehydration rates at a low temperature of 30℃ and are not suitable for low temperature demulsification at 30℃.

[0045] Test Example 3: High-Temperature Demulsification Test of Demulsifier Experiments were conducted on produced fluid samples from a joint station in Shengli Oilfield. The water content of the samples was 42%, the dehydration temperature was 85℃, and the test volume was 80 mL. The test results for each reagent are shown in Table 3. Table 3 Dehydration data for demulsifiers

[0046] As shown in Table 3, the demulsifiers 1#-4# provided in Examples 1-4 still exhibited high dehydration rates at 85℃, indicating that the products in these examples are suitable for demulsification at 85℃. However, in the field, when the demulsification temperature increased from 60℃ to 85℃, the demulsification rate decreased from 92.3% to 67.0%, showing a significant reduction in demulsification effectiveness. The demulsifiers provided in Comparative Examples 1-6 all had low dehydration rates at 85℃, making them unsuitable for demulsification at 85℃.

[0047] Figure 1 The image shows the GPC diagram of fluorinated polyether demulsifier 1#. The molecular weight of fluorinated polyether demulsifier 1# provided in Example 1 was determined, and the weight-average molecular weight can reach 21217.

[0048] Figure 2 Infrared spectrum of fluorinated polyether demulsifier #1, 1180 cm⁻¹ -1 This is the CF stretching vibration peak in 2,2,3,4,4,4-hexafluorobutyl methacrylate, at 1210 cm⁻¹. -1 The peak value for stretching vibration of CF2 is 1278 cm⁻¹. -1 The stretching vibration peak of CF3 is 1730 cm⁻¹. -1 The absorption peak for C=O in 2,2,3,4,4,4-hexafluorobutyl methacrylate is 3000-3100 cm⁻¹. -1 The absence of an absorption peak at 1100 cm⁻¹ indicates the absence of a C=C double bond, suggesting that 2,2,3,4,4,4-hexafluorobutyl methacrylate underwent a polymerization reaction with allyl glycidyl ether. -1 The peak at this point represents the stretching vibration of the ether bond (COC), indicating that propylene oxide, ethylene oxide, and the epoxy structure of the polymer underwent a ring-opening polymerization reaction.

[0049] The above description is merely an embodiment of this application, and the scope of protection of this application is not limited to these specific embodiments, but is determined by the claims of this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the technical concept and principles of this application should be included within the scope of protection of this application.

Claims

1. A method for preparing a fluorinated polyether demulsifier, characterized in that, include: (1) Add allyl glycidyl ether, 2,2,3,4,4,4-hexafluorobutyl methacrylate and aromatic solvent to a flask, stir and heat to 110-130℃, add 1 part of initiator, maintain the temperature at 120-130℃ for reaction, add 1 part of initiator every 0.5-1.5h, add a total of 5 parts, and then continue to keep the reaction at 120-130℃ for 1-3h to form a polymer solution; (2) Add the polymer solution and catalyst formed in step (1) into the reactor, remove oxygen by nitrogen replacement, and introduce propylene oxide at 120-130℃ for stirring reaction. After the reaction is completed, remove solvent and impurities under vacuum, purify, and form polymer polyether head. (3) Add the polymer polyether head and catalyst formed in step (2) into the reactor, remove oxygen by nitrogen replacement, and stir the reaction by introducing propylene oxide at 120-130℃. After the reaction is completed, age the reaction for 0.5-1.5h, and then stir the reaction by introducing ethylene oxide at 120-130℃. After the reaction is completed, age the reaction for 0.5-1.5h to obtain the fluorinated polyether demulsifier. In step (3), the mass ratio of the polymer polyether head, propylene oxide and ethylene oxide is 1:(10-30):(5-15).

2. The method according to claim 1, characterized in that, In step (1), the aromatic solvent is toluene and / or xylene; And / or, the initiator is selected from any one of di-tert-butyl peroxide, tert-butyl peroxide, and dicumyl peroxide.

3. The method according to claim 1, characterized in that, In step (1), the mass ratio of allyl glycidyl ether to 2,2,3,4,4,4-hexafluorobutyl methacrylate is 1:(2.0-2.5). And / or, the mass ratio of the aromatic solvent to the total mass of the polymerizing monomer is 1:(2.0-3.0). And / or, the initiator accounts for 0.3-1 wt% of the total mass of the polymerizing monomers.

4. The method according to claim 1, characterized in that, In steps (2) and (3), the catalyst is selected from any one of potassium hydroxide, potassium methoxide, potassium ethoxide and DMC bimetallic catalyst.

5. The method according to claim 1, characterized in that, In step (2), the mass ratio of the polymer solution to propylene oxide is 1:(2-2.6). And / or, the amount of the catalyst is 0.3-1 wt% of the mass of propylene oxide.

6. The method according to claim 1, characterized in that, In step (3), the amount of catalyst used is 0.2-0.8 wt% of the total mass of propylene oxide and ethylene oxide.

7. A fluorinated polyether demulsifier, characterized in that, The fluorinated polyether demulsifier is prepared by the method described in any one of claims 1-6.

8. The fluorinated polyether demulsifier according to claim 7, characterized in that, The molecular weight of the fluorinated polyether demulsifier is 10,000-30,000.

9. The application of the fluorinated polyether demulsifier as described in claim 7 in the process of demulsification and dehydration of produced crude oil.

10. The application according to claim 9, characterized in that, The amount of the fluorinated polyether demulsifier used is 90-110 ppm.

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