Oil and gas well demulsifier

Abstract

The invention relates to the technical field of demulsifiers, and discloses an oil and gas well demulsifier. The invention provides a demulsifier for oil and gas wells by adding silane quaternary phosphonium salt modified polyether, hydroxyethyl cellulose modified by pyridine modified quaternary ammonium salt, and 1-ethyl-3-methylimidazolium bromide into a reactor, mixing and stirring. The silicon oxygen bond and benzene ring structure in the silane quaternary phosphonium salt modified polyether improve the high temperature resistance of the demulsifier; the quaternary phosphonium salt and the quaternary ammonium salt enhance the demulsification effect; the polyether can penetrate into the interface of the emulsion droplet to play a demulsification effect; the adamantane structure enhances the high temperature resistance of the demulsifier; the hydroxyethyl cellulose modified by pyridine modified quaternary ammonium salt has amphiphilicity, interacts with the surface molecules of the emulsion droplets, promotes the coalescence and separation of the emulsion droplets, and realizes demulsification, and the hydroxyethyl cellulose modified by pyridine modified quaternary ammonium salt has a large molecular weight and a complex structure, occupies a large space at the oil-water interface, prevents the mutual contact and coalescence of the emulsion droplets, and enhances the demulsification effect.

Description

Technical Field

[0001] The invention relates to the technical field of demulsifiers, in particular to an oil and gas well demulsifier. Background Art

[0002] Demulsifier is an indispensable chemical auxiliary agent for all oil fields. It undertakes the task of demulsifying and dehydrating crude oil emulsions. With the secondary and tertiary oil recovery in oil fields, the addition of various oil displacement surfactants, polymers and other chemical agents also makes it difficult to quickly demulsify and separate the produced emulsified crude oil. Commonly used demulsifiers may cause the active substances in the demulsifier to be unstable at higher temperatures and fail to fully play their role, thereby affecting the demulsification effect. Therefore, it is of great significance to develop a demulsifier that is resistant to high temperatures and can demulsify efficiently. For example, in the document "Synthesis and Performance Evaluation of Cationic Block Polyether Demulsifiers", it is reported that a series of cationic block polyether demulsifiers were synthesized with ethylene glycol, epichlorohydrin, ethylene oxide and propylene oxide as main raw materials, which have good demulsification effects, but the high temperature resistance of the demulsifier has not been improved. The present invention aims to improve the demulsification effect of the demulsifier while making the demulsifier have excellent high temperature resistance. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] In view of the deficiencies in the prior art, the present invention provides an oil and gas well demulsifier, which has good demulsification effect and high temperature resistance.

[0005] (II) Technical solution

[0006] To achieve the above objectives, the present invention provides the following technical solution: an oil and gas well demulsifier, comprising the following components by weight: 14-18 parts by weight of silane quaternary phosphonium salt modified polyether, 10-15 parts by weight of pyridine-modified quaternary ammonium salt modified hydroxyethyl cellulose, and 4-6 parts by weight of 1-ethyl-3-methylimidazolium bromide.

[0007] Preferably, the preparation method of the silane quaternary phosphonium salt modified polyether comprises the following steps:

[0008] (1) Add 8-12 g of 3-chloropropyltrimethoxysilane to N,N-dimethylformamide solvent, stir to dissolve, heat to 85-100° C., dropwise add 10-15 g of 2-(diphenylphosphino)ethylamine, and after the dropwise addition is complete, reflux and react at a constant temperature for 8-12 h. After the reaction is complete, cool and distill under reduced pressure to obtain a silane quaternary phosphonium salt;

[0009] (2) adding 12-18 g of silane quaternary phosphonium salt and 10-15 g of 2,6-dialdehyde-1,5-dihydroxynaphthalene to an anhydrous ethanol solvent, stirring and mixing, and then adding 5-7 g of anhydrous magnesium sulfate dehydrating agent thereto, reflux reaction under nitrogen atmosphere for 10-14 h, after the reaction is completed, suction filtration and spin drying, then washing with ethyl acetate, and vacuum drying to obtain a silane quaternary phosphonium salt modified initiator;

[0010] (3) Add 15-20 g of propylene oxide, 6-9 g of silane quaternary phosphonium salt modified initiator, and 0.05-0.08 g of sodium hydroxide catalyst to a high-pressure reactor, heat to 150-160 ° C, react for 2-3.5 hours, cool to 30-40 ° C, add 18-25 g of ethylene oxide, heat to 130-140 ° C, continue to react for 3-5 hours, and after the reaction is completed, add 7%-9% acetic acid solution by mass, adjust the pH to 6-7, and obtain a silane quaternary phosphonium salt modified polyether.

[0011] Preferably, the dripping rate of 2-(diphenylphosphino)ethylamine in step (1) is controlled at 8-12 drops / min.

[0012] Preferably, the reaction temperature in step (2) is 45-60°C.

[0013] Preferably, the method for preparing the hydroxyethyl cellulose modified with pyridine-modified quaternary ammonium salt comprises the following steps:

[0014] S1. Add 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester and potassium hydroxide catalyst to toluene solvent, stir and mix, react at 28-35° C. for 3-4 hours, filter, wash and dry after the reaction to obtain intermediate 1;

[0015] S2. Add 13-17 g of N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine and 7-10 g of intermediate 1 to an acetone solvent, stir to dissolve, heat to 60-80 ° C, reflux for 9-10 hours, and after the reaction is completed, cool, filter, wash with ether and dry to obtain a quaternary ammonium salt modified with pyridine;

[0016] S3. Dissolve 8-12 g of hydroxyethyl cellulose in dehydrated dimethyl sulfoxide solvent, add 6-10 g of quaternary ammonium salt modified with pyridine, stir and mix, heat to 60-68°C, add 0.07-0.08 g of catalyst, reflux for 45-60 min, cool after the reaction, remove the dimethyl sulfoxide solvent by solvent replacement with ethyl acetate, filter to obtain a solid product, disperse the solid product in distilled water and dialyze for 15-20 h, rotary evaporate, and freeze-dry to obtain hydroxyethyl cellulose modified with quaternary ammonium salt modified with pyridine.

[0017] Preferably, the mass ratio of 2-amino-3,5-dibromo-4-methylpyridine, 1,3-adamantyl dimethacrylate and potassium hydroxide in S1 is 1:0.5-0.7:0.03-0.06.

[0018] Preferably, the catalyst in S3 is tin tetrachloride.

[0019] Preferably, the preparation method of the oil and gas well demulsifier is: adding silane quaternary phosphonium salt modified polyether, pyridine-modified quaternary ammonium salt modified hydroxyethyl cellulose, and 1-ethyl-3-methylimidazolium bromide into a reactor, mixing and stirring at 1300-1500 rpm for 12-15 minutes to obtain the oil and gas well demulsifier.

[0020] (III) Beneficial technical effects

[0021] The invention obtains an oil and gas well demulsifier by adding silane quaternary phosphonium salt modified polyether, pyridine-modified quaternary ammonium salt modified hydroxyethyl cellulose and 1-ethyl-3-methylimidazolium bromide into a reactor, mixing and stirring.

[0022] The chlorine in 3-chloropropyltrimethoxysilane reacts with 2-(diphenylphosphino)ethylamine to undergo quaternary phosphonium reaction, and an amino group is introduced to obtain a silane quaternary phosphonium salt. The amino group in the silane quaternary phosphonium salt reacts with the aldehyde group in 2,6-dialdehyde-1,5-dihydroxynaphthalene to undergo a Schiff base synthesis reaction to obtain a silane quaternary phosphonium salt modified initiator. The silane quaternary phosphonium salt modified initiator undergoes a polymerization reaction with propylene oxide and ethylene oxide to obtain a silane quaternary phosphonium salt modified polyether. The amino group in 2-amino-3,5-dibromo-4-methylpyridine and the double bond in 1,3-dimethylacrylate adamantyl undergo Michael addition reaction to obtain intermediate 1, the bromine in intermediate 1 and the tertiary amine in N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine undergo quaternization reaction to obtain a quaternary ammonium salt modified with pyridine, the epoxy group in the quaternary ammonium salt modified with the hydroxyl group in hydroxyethyl cellulose undergo ring-opening reaction to obtain hydroxyethyl cellulose modified with the quaternary ammonium salt modified with pyridine.

[0023] The bond energy of the silicon-oxygen bond in the silane quaternary phosphonium salt modified polyether is relatively high and is not easy to break at high temperatures, thereby maintaining the thermal stability of the demulsifier and improving the high temperature resistance of the demulsifier; the rigid structure of the benzene ring can enhance the rigidity and packing density of the polyether molecular chain, thereby improving the high temperature resistance of the demulsifier, and the conjugated effect formed by the double benzene ring structure of the naphthyl group further improves the thermal stability of the demulsifier; the positive charge contained in the quaternary phosphonium salt and the quaternary ammonium salt interacts with the negative charge on the surface of the emulsion droplets, neutralizes the charge on the surface of the emulsion droplets, thereby destroying the balanced stable charge protection layer of the emulsion droplets, increasing the collision and agglomeration probability between the oil droplets, promoting oil-water separation, and enhancing the demulsification effect of the demulsifier; the polyether has an excellent balance of hydrophilicity and lipophilicity, can quickly penetrate into the interface of the emulsion droplets, destroy the stability of the emulsion, aggregate the oil droplets, thereby achieving oil-water separation and playing a demulsification role; the quaternary ammonium salt modified hydroxyethyl fiber containing pyridine The pyridine group in cellulose has strong polarity and hydrophilicity, which increases the interfacial activity of the demulsifier and makes it easier for the demulsifier to adsorb on the oil-water interface, thereby more effectively destroying the stability of the emulsion and enhancing the demulsification effect; the highly symmetrical rigid structure of adamantane has extremely high thermal stability, which improves the high temperature resistance of the demulsifier; the main chain of hydroxyethyl cellulose is hydrophilic, and by grafting side chains with hydrophobic groups on its hydroxyl groups, the obtained quaternary ammonium salt-modified hydroxyethyl cellulose containing pyridine has amphiphilicity, and through molecular interaction with the surface of the emulsion droplets, the surface tension of the oil-water interface is reduced, and the coalescence and separation of the emulsion droplets are promoted, thereby achieving demulsification. In addition, the quaternary ammonium salt-modified hydroxyethyl cellulose containing pyridine has a large molecular weight and complex structure, occupies a large space on the oil-water interface, forms a stable protective film, prevents the mutual contact and coalescence between the emulsion droplets, thereby enhancing the demulsification effect. DETAILED DESCRIPTION

[0024] Example 1

[0025] (1) Add 8 g of 3-chloropropyltrimethoxysilane to N,N-dimethylformamide solvent, stir to dissolve, heat to 85° C., dropwise add 10 g of 2-(diphenylphosphino)ethylamine at a rate of 8 drops / min, and after the dropwise addition is completed, reflux and react at a constant temperature for 8 h. After the reaction is completed, cool and distill under reduced pressure to obtain a silane quaternary phosphonium salt;

[0026] (2) adding 12 g of silane quaternary phosphonium salt and 10 g of 2,6-dialdehyde-1,5-dihydroxynaphthalene to an anhydrous ethanol solvent, stirring and mixing, and then adding 5 g of anhydrous magnesium sulfate dehydrating agent thereto, reflux reaction for 10 h under a nitrogen atmosphere, the reaction temperature is 45 ° C. After the reaction is completed, suction filtration and spin drying are performed, and then washed with ethyl acetate and vacuum dried to obtain a silane quaternary phosphonium salt modified initiator;

[0027] (3) adding 15 g of propylene oxide, 6 g of silane quaternary phosphonium salt modified initiator, and 0.05 g of sodium hydroxide catalyst to a high-pressure reactor, heating to 150° C., reacting for 2 h, cooling to 30° C., adding 18 g of ethylene oxide, heating to 130° C., and continuing to react for 3 h. After the reaction is completed, adding 7% acetic acid solution by mass, adjusting the pH to 6, and obtaining a silane quaternary phosphonium salt modified polyether;

[0028] (4) adding 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide catalyst to a toluene solvent, wherein the mass ratio of 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide is 1:0.5:0.03, stirring and mixing, reacting at 28° C. for 3 h, and filtering, washing, and drying after the reaction to obtain an intermediate 1;

[0029] (5) Add 13 g of N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine and 7 g of intermediate 1 to an acetone solvent, stir to dissolve, heat to 60° C., and reflux for 9 h. After the reaction is completed, cool, filter, wash with ether, and dry to obtain a quaternary ammonium salt modified with pyridine;

[0030] (6) 8 g of hydroxyethyl cellulose was dissolved in dehydrated dimethyl sulfoxide solvent, 6 g of quaternary ammonium salt containing pyridine was added thereto, the mixture was stirred and mixed, the temperature was raised to 60° C., 0.07 g of tin tetrachloride catalyst was added thereto, and the reaction was refluxed for 45 min. After the reaction was completed, the mixture was cooled, the dimethyl sulfoxide solvent was removed by solvent replacement with ethyl acetate, and a solid product was obtained by suction filtration. The solid product was dispersed in distilled water and dialyzed for 15 h, rotary evaporated, and freeze-dried to obtain hydroxyethyl cellulose containing quaternary ammonium salt modified with pyridine;

[0031] (7) 14 parts by weight of silane quaternary phosphonium salt modified polyether, 10 parts by weight of hydroxyethyl cellulose modified with pyridine-modified quaternary ammonium salt, and 4 parts by weight of 1-ethyl-3-methylimidazolium bromide were added to a reactor, and the mixture was mixed and stirred at 1300 rpm for 12 minutes to obtain an oil and gas well demulsifier.

[0032] Example 2

[0033] (1) Add 12 g of 3-chloropropyltrimethoxysilane to N,N-dimethylformamide solvent, stir to dissolve, heat to 100° C., dropwise add 15 g of 2-(diphenylphosphino)ethylamine at a rate of 12 drops / min, and after the dropwise addition is completed, reflux and react at a constant temperature for 12 h. After the reaction is completed, cool and distill under reduced pressure to obtain a silane quaternary phosphonium salt;

[0034] (2) adding 18 g of silane quaternary phosphonium salt and 15 g of 2,6-dialdehyde-1,5-dihydroxynaphthalene to an anhydrous ethanol solvent, stirring and mixing, and then adding 7 g of anhydrous magnesium sulfate dehydrating agent thereto, reflux reaction for 14 h under a nitrogen atmosphere, the reaction temperature is 60° C. After the reaction is completed, suction filtration and spin drying are performed, and then washing with ethyl acetate and vacuum drying are performed to obtain a silane quaternary phosphonium salt modified initiator;

[0035] (3) adding 20 g of propylene oxide, 9 g of silane quaternary phosphonium salt modified initiator, and 0.08 g of sodium hydroxide catalyst to a high-pressure reactor, heating to 160° C., reacting for 3.5 h, cooling to 40° C., adding 25 g of ethylene oxide, heating to 140° C., and continuing to react for 5 h. After the reaction is completed, adding 9% acetic acid solution by mass, adjusting the pH to 7, and obtaining a silane quaternary phosphonium salt modified polyether;

[0036] (4) adding 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide catalyst to a toluene solvent, wherein the mass ratio of 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide is 1:0.7:0.06, stirring and mixing, reacting at 35° C. for 4 hours, and after the reaction is completed, filtering, washing, and drying to obtain intermediate 1;

[0037] (5) Add 17 g of N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine and 10 g of intermediate 1 to an acetone solvent, stir to dissolve, heat to 80° C., and reflux for 10 h. After the reaction is completed, cool, filter, wash with ether, and dry to obtain a quaternary ammonium salt modified with pyridine;

[0038] (6) dissolving 12 g of hydroxyethyl cellulose in dehydrated dimethyl sulfoxide solvent, adding 10 g of quaternary ammonium salt containing pyridine, stirring and mixing, heating to 68° C., adding 0.08 g of tin tetrachloride catalyst, reflux reaction for 60 min, cooling after the reaction, removing the dimethyl sulfoxide solvent by solvent replacement with ethyl acetate, filtering to obtain a solid product, dispersing the solid product in distilled water and dialyzing for 20 h, rotary evaporating, and freeze-drying to obtain quaternary ammonium salt-modified hydroxyethyl cellulose containing pyridine;

[0039] (7) 18 parts by weight of silane quaternary phosphonium salt modified polyether, 15 parts by weight of pyridine-modified quaternary ammonium salt modified hydroxyethyl cellulose, and 6 parts by weight of 1-ethyl-3-methylimidazolium bromide were added to a reactor, and the mixture was mixed and stirred at 1500 rpm for 15 minutes to obtain an oil and gas well demulsifier.

[0040] Example 3

[0041] (1) Add 10 g of 3-chloropropyltrimethoxysilane to N,N-dimethylformamide solvent, stir to dissolve, heat to 92° C., dropwise add 12.5 g of 2-(diphenylphosphino)ethylamine at a rate of 10 drops / min, and after the dropwise addition is completed, reflux and react at a constant temperature for 10 h. After the reaction is completed, cool and distill under reduced pressure to obtain a silane quaternary phosphonium salt;

[0042] (2) adding 15 g of silane quaternary phosphonium salt and 12.5 g of 2,6-dialdehyde-1,5-dihydroxynaphthalene to an anhydrous ethanol solvent, stirring and mixing, and then adding 6 g of anhydrous magnesium sulfate dehydrating agent thereto, reflux reaction for 12 h under a nitrogen atmosphere, the reaction temperature is 53 ° C. After the reaction is completed, suction filtration and spin drying are performed, and then washed with ethyl acetate and vacuum dried to obtain a silane quaternary phosphonium salt modified initiator;

[0043] (3) adding 17.5 g of propylene oxide, 7.5 g of silane quaternary phosphonium salt modified initiator, and 0.065 g of sodium hydroxide catalyst to a high-pressure reactor, heating to 155° C., reacting for 2.7 h, cooling to 35° C., adding 21.5 g of ethylene oxide, heating to 135° C., and continuing to react for 4 h. After the reaction is completed, adding 8% acetic acid solution by mass, adjusting the pH to 6.5, and obtaining a silane quaternary phosphonium salt modified polyether;

[0044] (4) adding 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide catalyst to a toluene solvent, wherein the mass ratio of 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide is 1:0.6:0.045, stirring and mixing, reacting at 32° C. for 3.5 hours, and filtering, washing, and drying after the reaction to obtain an intermediate 1;

[0045] (5) Add 15 g of N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine and 8.5 g of intermediate 1 to an acetone solvent, stir and dissolve, heat to 70° C., and reflux for 9.5 h. After the reaction is completed, cool, filter, wash with ether, and dry to obtain a quaternary ammonium salt modified with pyridine;

[0046] (6) Dissolve 10 g of hydroxyethyl cellulose in dehydrated dimethyl sulfoxide solvent, add 8 g of quaternary ammonium salt modified with pyridine, stir and mix, heat to 64° C., add 0.075 g of tin tetrachloride catalyst, reflux for 52 min, cool after the reaction, replace the dimethyl sulfoxide solvent with ethyl acetate, filter to obtain a solid product, disperse the solid product in distilled water and dialyze for 17.5 h, rotary evaporate, and freeze-dry to obtain quaternary ammonium salt modified hydroxyethyl cellulose;

[0047] (7) 16 parts by weight of silane quaternary phosphonium salt modified polyether, 12 parts by weight of hydroxyethyl cellulose modified with pyridine-containing quaternary ammonium salt, and 5 parts by weight of 1-ethyl-3-methylimidazolium bromide were added to a reactor, and the mixture was mixed and stirred at 1400 rpm for 13 minutes to obtain an oil and gas well demulsifier.

[0048] Example 4

[0049] (1) Add 10 g of 3-chloropropyltrimethoxysilane to N,N-dimethylformamide solvent, stir to dissolve, heat to 92° C., dropwise add 12.5 g of 2-(diphenylphosphino)ethylamine at a rate of 10 drops / min, and after the dropwise addition is completed, reflux and react at a constant temperature for 10 h. After the reaction is completed, cool and distill under reduced pressure to obtain a silane quaternary phosphonium salt;

[0050] (2) adding 15 g of silane quaternary phosphonium salt and 12.5 g of 2,6-dialdehyde-1,5-dihydroxynaphthalene to an anhydrous ethanol solvent, stirring and mixing, and then adding 6 g of anhydrous magnesium sulfate dehydrating agent thereto, reflux reaction for 12 h under a nitrogen atmosphere, the reaction temperature is 53 ° C. After the reaction is completed, suction filtration and spin drying are performed, and then washed with ethyl acetate and vacuum dried to obtain a silane quaternary phosphonium salt modified initiator;

[0051] (3) adding 20 g of propylene oxide, 9 g of silane quaternary phosphonium salt modified initiator, and 0.08 g of sodium hydroxide catalyst to a high-pressure reactor, heating to 160° C., reacting for 3.5 h, cooling to 40° C., adding 25 g of ethylene oxide, heating to 140° C., and continuing to react for 5 h. After the reaction is completed, adding 9% acetic acid solution by mass, adjusting the pH to 7, and obtaining a silane quaternary phosphonium salt modified polyether;

[0052] (4) adding 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide catalyst to a toluene solvent, wherein the mass ratio of 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide is 1:0.7:0.06, stirring and mixing, reacting at 35° C. for 4 hours, and after the reaction is completed, filtering, washing, and drying to obtain intermediate 1;

[0053] (5) Add 13 g of N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine and 7 g of intermediate 1 to an acetone solvent, stir to dissolve, heat to 60° C., and reflux for 9 h. After the reaction is completed, cool, filter, wash with ether, and dry to obtain a quaternary ammonium salt modified with pyridine;

[0054] (6) 8 g of hydroxyethyl cellulose was dissolved in dehydrated dimethyl sulfoxide solvent, 6 g of quaternary ammonium salt containing pyridine was added thereto, the mixture was stirred and mixed, the temperature was raised to 60° C., 0.07 g of tin tetrachloride catalyst was added thereto, and the reaction was refluxed for 45 min. After the reaction was completed, the mixture was cooled, the dimethyl sulfoxide solvent was removed by solvent replacement with ethyl acetate, and a solid product was obtained by suction filtration. The solid product was dispersed in distilled water and dialyzed for 15 h, rotary evaporated, and freeze-dried to obtain hydroxyethyl cellulose containing quaternary ammonium salt modified with pyridine;

[0055] (7) 14 parts by weight of silane quaternary phosphonium salt modified polyether, 10 parts by weight of hydroxyethyl cellulose modified with pyridine-modified quaternary ammonium salt, and 4 parts by weight of 1-ethyl-3-methylimidazolium bromide were added to a reactor, and the mixture was mixed and stirred at 1300 rpm for 12 minutes to obtain an oil and gas well demulsifier.

[0056] Example 5

[0057] (1) Add 8 g of 3-chloropropyltrimethoxysilane to N,N-dimethylformamide solvent, stir to dissolve, heat to 85° C., dropwise add 10 g of 2-(diphenylphosphino)ethylamine at a rate of 8 drops / min, and after the dropwise addition is completed, reflux and react at a constant temperature for 8 h. After the reaction is completed, cool and distill under reduced pressure to obtain a silane quaternary phosphonium salt;

[0058] (2) adding 12 g of silane quaternary phosphonium salt and 10 g of 2,6-dialdehyde-1,5-dihydroxynaphthalene to an anhydrous ethanol solvent, stirring and mixing, and then adding 5 g of anhydrous magnesium sulfate dehydrating agent thereto, reflux reaction for 10 h under a nitrogen atmosphere, the reaction temperature is 45 ° C. After the reaction is completed, suction filtration and spin drying are performed, and then washed with ethyl acetate and vacuum dried to obtain a silane quaternary phosphonium salt modified initiator;

[0059] (3) adding 17.5 g of propylene oxide, 7.5 g of silane quaternary phosphonium salt modified initiator, and 0.065 g of sodium hydroxide catalyst to a high-pressure reactor, heating to 155° C., reacting for 2.7 h, cooling to 35° C., adding 21.5 g of ethylene oxide, heating to 135° C., and continuing to react for 4 h. After the reaction is completed, adding 8% acetic acid solution by mass, adjusting the pH to 6.5, and obtaining a silane quaternary phosphonium salt modified polyether;

[0060] (4) adding 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide catalyst to a toluene solvent, wherein the mass ratio of 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester, and potassium hydroxide is 1:0.6:0.045, stirring and mixing, reacting at 32° C. for 3.5 hours, and filtering, washing, and drying after the reaction to obtain an intermediate 1;

[0061] (5) Add 17 g of N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine and 10 g of intermediate 1 to an acetone solvent, stir to dissolve, heat to 80° C., and reflux for 10 h. After the reaction is completed, cool, filter, wash with ether, and dry to obtain a quaternary ammonium salt modified with pyridine;

[0062] (6) dissolving 12 g of hydroxyethyl cellulose in dehydrated dimethyl sulfoxide solvent, adding 10 g of quaternary ammonium salt containing pyridine, stirring and mixing, heating to 68° C., adding 0.08 g of tin tetrachloride catalyst, reflux reaction for 60 min, cooling after the reaction, removing the dimethyl sulfoxide solvent by solvent replacement with ethyl acetate, filtering to obtain a solid product, dispersing the solid product in distilled water and dialyzing for 20 h, rotary evaporating, and freeze-drying to obtain quaternary ammonium salt-modified hydroxyethyl cellulose containing pyridine;

[0063] (7) 18 parts by weight of silane quaternary phosphonium salt modified polyether, 15 parts by weight of pyridine-modified quaternary ammonium salt modified hydroxyethyl cellulose, and 6 parts by weight of 1-ethyl-3-methylimidazolium bromide were added to a reactor, and the mixture was mixed and stirred at 1500 rpm for 15 minutes to obtain an oil and gas well demulsifier.

[0064] Comparative Example 1

[0065] Compared with Example 1, the difference in this comparative example is that no silane quaternary phosphonium salt-modified polyether is added.

[0066] Comparative Example 2

[0067] Compared with Example 1, the difference in this comparative example is that no hydroxyethyl cellulose modified with pyridine-modified quaternary ammonium salt is added.

[0068] Referring to SY / T5281-2000, the demulsification performance of the demulsifier was tested, and the dehydration rate after demulsification for 1.5 hours was calculated, and the dehydration rate (%) = 1-dehydrated oil water content / crude oil water content, and the crude oil was obtained from Gudao Oil Production Plant. The test results are shown in Table 1.

[0069] Table 1: Demulsification performance test.

[0070] project Dehydration rate (%) Water phase cleanliness Example 1 94.3 Clear Example 2 95.2 Clear Example 3 92.8 Clear Example 4 93.7 Clear Example 5 96.4 Clear Comparative Example 1 74.5 Slightly turbid Comparative Example 2 72.1 Slightly turbid

[0071] As can be seen from Table 1, compared with Comparative Example 1-2, Examples 1-5 have a higher dehydration rate of crude oil and a clearer water phase, and have a better demulsification effect.

[0072] The high temperature resistance of the demulsifier was tested by a thermogravimetric analyzer under the following test conditions: under nitrogen conditions, the heating rate was 15°C / min, and the test range was 50-400°C. The test results are shown in Table 2.

[0073] Table 2: High temperature resistance test.

[0074]

[0075] It can be seen from Table 2 that Examples 1-5 have better high temperature resistance than Comparative Examples 1-2.

[0076] The preferred embodiments of the present invention disclosed above are only used to help illustrate the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to the specific implementation methods described. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. An oil and gas well demulsifier, characterized in that: The invention comprises the following components by weight: 14-18 parts by weight of silane quaternary phosphonium salt modified polyether, 10-15 parts by weight of pyridine-modified quaternary ammonium salt modified hydroxyethyl cellulose, and 4-6 parts by weight of 1-ethyl-3-methylimidazolium bromide.

2. The oil and gas well demulsifier according to claim 1, characterized in that: The preparation method of the silane quaternary phosphonium salt modified polyether comprises the following steps: (1) Add 8-12 g of 3-chloropropyltrimethoxysilane to N,N-dimethylformamide solvent, stir to dissolve, heat to 85-100° C., dropwise add 10-15 g of 2-(diphenylphosphino)ethylamine, and after the dropwise addition is complete, reflux and react at a constant temperature for 8-12 h. After the reaction is complete, cool and distill under reduced pressure to obtain a silane quaternary phosphonium salt; (2) adding 12-18 g of silane quaternary phosphonium salt and 10-15 g of 2,6-dialdehyde-1,5-dihydroxynaphthalene to an anhydrous ethanol solvent, stirring and mixing, and then adding 5-7 g of anhydrous magnesium sulfate dehydrating agent thereto, reflux reaction under nitrogen atmosphere for 10-14 h, after the reaction is completed, suction filtration and spin drying, then washing with ethyl acetate, and vacuum drying to obtain a silane quaternary phosphonium salt modified initiator; (3) Add 15-20 g of propylene oxide, 6-9 g of silane quaternary phosphonium salt modified initiator, and 0.05-0.08 g of sodium hydroxide catalyst to a high-pressure reactor, heat to 150-160 ° C, react for 2-3.5 hours, cool to 30-40 ° C, add 18-25 g of ethylene oxide, heat to 130-140 ° C, continue to react for 3-5 hours, and after the reaction is completed, add 7%-9% acetic acid solution by mass, adjust the pH to 6-7, and obtain a silane quaternary phosphonium salt modified polyether.

3. The oil and gas well demulsifier according to claim 2, characterized in that: In the step (1), the dripping rate of 2-(diphenylphosphino)ethylamine is controlled at 8-12 drops / min.

4. The oil and gas well demulsifier according to claim 2, characterized in that: The reaction temperature in step (2) is 45-60°C.

5. The oil and gas well demulsifier according to claim 1, characterized in that: The method for preparing hydroxyethyl cellulose modified with pyridine-modified quaternary ammonium salt comprises the following steps: S1. Add 2-amino-3,5-dibromo-4-methylpyridine, 1,3-dimethylacrylate adamantyl ester and potassium hydroxide catalyst to toluene solvent, stir and mix, react at 28-35° C. for 3-4 hours, filter, wash and dry after the reaction to obtain intermediate 1; S2. Add 13-17 g of N-(epoxypropyl)-N-phenyl-epoxyethylene methylamine and 7-10 g of intermediate 1 to an acetone solvent, stir to dissolve, heat to 60-80 ° C, reflux for 9-10 hours, and after the reaction is completed, cool, filter, wash with ether and dry to obtain a quaternary ammonium salt modified with pyridine; S3. Dissolve 8-12 g of hydroxyethyl cellulose in dehydrated dimethyl sulfoxide solvent, add 6-10 g of quaternary ammonium salt modified with pyridine, stir and mix, heat to 60-68°C, add 0.07-0.08 g of catalyst, reflux for 45-60 min, cool after the reaction, remove the dimethyl sulfoxide solvent by solvent replacement with ethyl acetate, filter to obtain a solid product, disperse the solid product in distilled water and dialyze for 15-20 h, rotary evaporate, and freeze-dry to obtain hydroxyethyl cellulose modified with quaternary ammonium salt modified with pyridine.

6. The oil and gas well demulsifier according to claim 5, characterized in that: The mass ratio of 2-amino-3,5-dibromo-4-methylpyridine, 1,3-adamantyl dimethacrylate and potassium hydroxide in S1 is 1:0.5-0.7:0.03-0.

06.

7. The oil and gas well demulsifier according to claim 5, characterized in that: The catalyst in S3 is tin tetrachloride.

8. A method for preparing an oil and gas well demulsifier according to any one of claims 1 to 7, characterized in that: The preparation method of the oil and gas well demulsifier comprises: adding silane quaternary phosphonium salt modified polyether, pyridine-modified quaternary ammonium salt modified hydroxyethyl cellulose and 1-ethyl-3-methylimidazolium bromide into a reactor, mixing and stirring at 1300-1500 rpm for 12-15 minutes to obtain the oil and gas well demulsifier.

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