Water-containing crude oil demulsifier as well as preparation method and application thereof

Abstract

The invention relates to a water-containing crude oil demulsifier as well as a preparation method and application thereof, the demulsifier disclosed by the invention is relatively high in branching degree and strong in interfacial activity, can obtain relatively high dehydration rate when being used for demulsifying water-containing crude oil, especially thick oil, and is especially suitable for an ore bed environment with high calcium and magnesium ion content and relatively low treatment temperature.

Description

Technical Field

[0001] This disclosure relates to the field of crude oil demulsification technology, specifically to a demulsifier for water-containing crude oil, its preparation method, and its application. Background Technology

[0002] As crude oil is continuously consumed and extracted, the reserves of easily accessible and high-quality crude oil are gradually decreasing. my country has abundant heavy oil reserves, accounting for more than 70% of its total crude oil reserves. Effective extraction of heavy oil is becoming increasingly important for my country's strategic and energy security. Due to its high viscosity and poor fluidity, heavy oil requires measures such as injecting chemical viscosity reducers and steam injection to lower its viscosity and increase its production. However, this process results in a rapid increase in the water content of the produced fluid and a complex composition, leading to significant challenges in later demulsification.

[0003] Currently, commonly used demulsification methods are divided into physical, chemical, and biological methods. Chemical demulsification methods involve adding demulsifiers to disrupt the oil-water interface film, causing oil droplets to coalesce and float while the aqueous phase settles, thus achieving oil-water separation. Commonly used demulsifiers include cationic (quaternary ammonium salts), anionic (sulfonates, carboxylates, etc.), and nonionic (block polyethers). Invention patent CN117229808 uses silicon-containing zwitterionic surfactants and fatty alcohols as demulsifiers for produced oil demulsification, achieving a dehydration rate of over 88%. Patent CN117186381 discloses a demulsifier for polymer flooding produced fluids. It uses guar gum, epoxidized soybean oil, ethylene oxide, and propylene oxide, among others, through a series of reactions to introduce polyether molecular chains and hydrophobic soybean oil chains into the guar gum matrix, generating a demulsifier for polymer flooding produced fluids. This demulsifier achieves excellent oil-water separation and a high dehydration rate. Studies have shown that increasing the branching of surfactants can enhance the dehydration capacity of demulsifiers. Patent CN113717061 discloses a Y-type demulsifier synthesized under specific conditions using glycerol triglycidyl ether and dodecylamine, achieving a demulsification rate of approximately 88%. Patent CN116589368 discloses an ionic liquid demulsifier generated by reacting di-secondary amine, alkyl glycidyl ether, and a dihalogenated derivative. This demulsifier is a typical multi-branched demulsifier, exhibiting significant dehydration effects when applied to crude oil demulsification. However, the demulsifiers disclosed in these patents are primarily used for demulsifying low-viscosity, water-containing crude oils.

[0004] Heavy oil is characterized by its high density and high content of asphaltenes and gums. Asphaltenes and gums are natural emulsifiers present within the oil, which accumulate at the oil-water interface, increasing the thickness and strength of the oil-water interface transition layer and forming a stable W / O emulsion. Therefore, the dehydration rate of existing conventional demulsifiers in heavy oil demulsification is often low and difficult to meet the requirements. Summary of the Invention

[0005] The purpose of this disclosure is to provide a demulsifier for water-containing crude oil, its preparation method and application. The demulsifier has the advantages of a wide applicable temperature range (20~80℃) and good oil-water separation effect, and is especially suitable for demulsification and dehydration of water-containing crude oil with high salt and high calcium and magnesium content.

[0006] To achieve the above objectives, a first aspect of this disclosure provides an aqueous crude oil demulsifier, said aqueous crude oil demulsifier comprising a polymer having the structure shown in Formula I:

[0007] Formula I Wherein, R1 and R2 may be the same or different, and are respectively selected from alkylene groups with 1 to 6 carbon atoms and alkene groups with 1 to 6 carbon atoms; R3 is selected from H, substituted or unsubstituted alkyl groups with 1 to 12 carbon atoms, alkoxy groups with 1 to 12 carbon atoms, substituted or unsubstituted phenyl groups with 6 to 12 carbon atoms, substituted or unsubstituted phenoxy groups, and heterocyclic groups with 2 to 10 carbon atoms. The substituents on the alkyl group include amino groups; The substituents on the phenyl group include alkyl groups having 1 to 6 carbon atoms; The substituents on the phenoxy group include alkyl groups having 1 to 6 carbon atoms; The heterocyclic group contains one or more of N, O and S atoms; Each R4 may be the same or different, and is selected from phenyl and alkyl groups having 1 to 12 carbon atoms, respectively; a1, a2, a3 and a4 may be the same or different, b1, b2, b3 and b4 may be the same or different, (b1+b2+b3+b4):(a1+a2+a3+a4) = (0.1~10):1.

[0008] Optionally, the weight-average molecular weight of the water-containing crude oil demulsifier is 1,000 to 10,000, preferably 2,000 to 5,000.

[0009] Optionally, R3 is selected from a heterocyclic group having 3 to 9 carbon atoms, wherein the heterocyclic group contains N atoms; Preferably, R3 is selected from the group consisting of: , , , , , , , .

[0010] Optionally, each R4 may be the same or different, and may be selected from alkyl groups having 4 to 8 carbon atoms.

[0011] A second aspect of this disclosure provides a method for preparing a demulsifier for water-containing crude oil, the method comprising: S1. A polyamine having the structure shown in Formula II is contacted with an epoxide having the structure shown in Formula III to carry out a first reaction, thereby obtaining a first intermediate. S2. The first intermediate is contacted with propylene oxide to carry out a second reaction, thereby obtaining a second intermediate; S3. The second intermediate is brought into contact with ethylene oxide to carry out the third reaction;

[0012] Formula II;

[0013] Formula III; Wherein, R1 and R2 may be the same or different, and are respectively selected from alkylene groups with 1 to 6 carbon atoms and alkene groups with 1 to 6 carbon atoms; R3 is selected from H, substituted or unsubstituted alkyl groups with 1 to 12 carbon atoms, alkoxy groups with 1 to 12 carbon atoms, substituted or unsubstituted phenyl groups with 6 to 12 carbon atoms, substituted or unsubstituted phenoxy groups, and heterocyclic groups with 2 to 10 carbon atoms. The substituents on the alkyl group include amino groups; The substituents on the phenyl group include alkyl groups having 1 to 6 carbon atoms; The substituents on the phenoxy group include alkyl groups having 1 to 6 carbon atoms; The heterocyclic group contains one or more of N, O and S atoms; Each R4 may be the same or different, and is selected from phenyl and alkyl groups having 1 to 12 carbon atoms, respectively; The molar ratio of ethylene oxide to propylene oxide is (0.1~10):1.

[0014] Optionally, R3 is selected from a heterocyclic group having 3 to 9 carbon atoms, wherein the heterocyclic group contains N atoms; Preferably, R3 is selected from the group consisting of: , , , , , , , ; Optionally, each R4 may be the same or different, and may be selected from alkyl groups having 4 to 8 carbon atoms.

[0015] Optionally, steps S1 to S3 are performed under an inert atmosphere, which includes nitrogen and / or argon.

[0016] Optionally, step S1 is carried out in the presence of a solvent, which includes one or more of saturated monohydric alcohols with 1 to 3 carbon atoms and dichloromethane. The total concentration of the polyamine and the epoxide is 10-60% by weight, preferably 20-50% by weight, relative to the total weight of the solvent, the polyamine and the epoxide.

[0017] Optionally, in step S1, the molar ratio of the epoxide to the polyamine is (4~40):1; The conditions for the first reaction include: a time of 2 to 24 hours and a temperature of 60 to 150°C.

[0018] Optionally, in step S2, the weight ratio of propylene oxide to the first intermediate is (1~10):1, preferably (1~5):1; The conditions for the second reaction include: time of 30-120 min, temperature of 105-125℃, and pressure of 0.3-1 MPa; The second reaction is carried out in the presence of a base, which includes sodium hydroxide and / or potassium hydroxide; The weight ratio of the alkali to the first intermediate is (0.25~1):100.

[0019] Optionally, in step S3, the conditions for the third reaction include: a time of 30-120 min and a temperature of 105-125 °C; The molar ratio of ethylene oxide to propylene oxide is (0.5~5):1.

[0020] The third aspect of this disclosure provides a demulsifier for water-containing crude oil prepared using the method described in the second aspect of this disclosure.

[0021] The fourth aspect of this disclosure provides a method for demulsifying water-containing crude oil, wherein the water-containing crude oil is contacted with the water-containing crude oil demulsifier described in the first or third aspect of this disclosure.

[0022] Optionally, the water-containing crude oil includes water-containing heavy oil, which has a viscosity of 2000~100000 mPa·s at 50°C and a water content of 10~85% by weight.

[0023] Optionally, the contact includes: mixing the aqueous crude oil with a solution containing the aqueous crude oil demulsifier and then allowing it to stand; The contact temperature is 20~80℃, and the standing time is 30~240min; In the solution of the water-containing crude oil demulsifier, the concentration of the water-containing crude oil demulsifier is 0.001~0.5% by weight. The amount of demulsifier used for the aqueous crude oil is 1.25~1000mg relative to 1L of the aqueous crude oil.

[0024] Through the above technical solution, the demulsifier disclosed herein exhibits a high degree of branching and strong interfacial activity. When applied to demulsifying water-bearing crude oil, especially heavy oil, multiple branches interact strongly with the gums and asphaltenes in the heavy oil through electrostatic and hydrogen bonding, disrupting the stable oil-water interface. Water droplets coalesce and settle out, achieving the purpose of demulsification and dehydration. Simultaneously, the demulsifier disclosed herein can replace gums and asphaltenes, accumulating at the oil-water interface, reducing the interfacial tension and Gibbs free energy, exhibiting good interfacial activity, promoting phase transformation, and disrupting the original W / O system to achieve demulsification. It is particularly suitable for mineral formations with high calcium and magnesium ion content. This disclosure has broad application potential in the field of heavy oil demulsification.

[0025] Other features and advantages of this disclosure will be described in detail in the following detailed description section. Attached Figure Description

[0026] The accompanying drawings are provided to further illustrate the present disclosure and form part of the specification. They are used together with the following detailed description to explain the present disclosure, but do not constitute a limitation thereof. In the drawings: Figure 1 This is the carbon NMR spectrum of the demulsifier A1 prepared in Example 1 of this disclosure.

[0027] Figure 2 The image shows the carbon NMR spectrum of the demulsifier A2 prepared in Example 2 of this disclosure.

[0028] Figure 3 This is the carbon NMR spectrum of the demulsifier A3 prepared in Example 3 of this disclosure.

[0029] Figure 4 The image shows the carbon NMR spectrum of the demulsifier A4 prepared in Example 4 of this disclosure. Detailed Implementation

[0030] The specific embodiments of this disclosure will be described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are for illustration and explanation only and are not intended to limit this disclosure.

[0031] The first aspect of this disclosure provides an aqueous crude oil demulsifier, said aqueous crude oil demulsifier comprising a polymer having the structure shown in Formula I:

[0032] Formula I Wherein, R1 and R2 may be the same or different, and are respectively selected from alkylene groups with 1 to 6 carbon atoms and alkene groups with 1 to 6 carbon atoms; R3 is selected from H, substituted or unsubstituted alkyl groups with 1 to 12 carbon atoms, alkoxy groups with 1 to 12 carbon atoms, substituted or unsubstituted phenyl groups with 6 to 12 carbon atoms, substituted or unsubstituted phenoxy groups, and heterocyclic groups with 2 to 10 carbon atoms. The substituents on the alkyl group include amino groups; The substituents on the phenyl group include alkyl groups having 1 to 6 carbon atoms; The substituents on the phenoxy group include alkyl groups having 1 to 6 carbon atoms; The heterocyclic group contains one or more of N, O and S atoms; Each R4 may be the same or different, and is selected from phenyl and alkyl groups having 1 to 12 carbon atoms, respectively; a1, a2, a3 and a4 may be the same or different, b1, b2, b3 and b4 may be the same or different, (b1+b2+b3+b4):(a1+a2+a3+a4) = (0.1~10):1.

[0033] Crude oil extraction involves extensive water injection processes (such as active water flooding and condensate water generated from steam injection), resulting in high water content in the produced liquid oil. This water forms a stable w / o emulsion system with the crude oil. Compared to ordinary crude oil, heavy oil is characterized by high content of gums and asphaltenes. These naturally polar components are adsorbed at the oil-water interface, forming a more stable w / o emulsion. The demulsifier disclosed in this invention has the advantages of high branching degree and strong interfacial activity. It has multiple contact points with asphaltenes at the oil-water interface, occupying a larger interfacial area. Multiple branches can interact strongly with gums and asphaltenes through electrostatic and hydrogen bonding, disrupting the stable oil-water interface. Water droplets aggregate and settle out, achieving the purpose of demulsification and dehydration. On the other hand, the demulsifier replaces the asphaltenes and accumulates at the oil-water interface, reducing the interfacial tension and Gibbs free energy, exhibiting good interfacial activity, promoting phase transformation, disrupting the original W / O system, and achieving demulsification. While achieving a high dehydration rate, it lowers the dehydration temperature, increases the oil-water sedimentation and separation rate, and reduces the oil content in wastewater and the water content in oil. Simultaneously, the applicant unexpectedly discovered that the demulsifier disclosed herein is particularly suitable for high-mineralization environments with high calcium and magnesium ion content, effectively reducing interfacial tension. For example, in mineralization environments with calcium and magnesium ion content >7000 mg / L, the interfacial tension is reduced to 10. -2 mN / m.

[0034] In this disclosure, "heterocyclic group" refers to a group whose cyclic atoms include heteroatoms, which include one or more of N, O and S atoms.

[0035] In this disclosure, the number of carbon atoms includes the total number of carbon atoms in the group, and if the group has substituents, the number of carbon atoms includes the total number of carbon atoms in the group and the substituents. For example, a methyl-substituted phenyl group has 7 carbon atoms.

[0036] In this disclosure, the number of carbon atoms in "substituted or unsubstituted alkyl group having 1 to 12 carbon atoms" can be 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12. "Unsubstituted alkyl group having 1 to 12 carbon atoms" can include substituted or unsubstituted straight-chain alkyl groups having 1 to 12 carbon atoms and substituted or unsubstituted branched alkyl groups having 3 to 12 carbon atoms. Specific examples of "substituted or unsubstituted alkyl group having 1 to 12 carbon atoms" include, but are not limited to, examples from other sources. The compounds include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, isopentyl, neopentyl, n-hexyl, n-octyl, 2-ethylhexyl, nonyl, decyl, 3,7-dimethyloctyl, amino-substituted methyl, amino-substituted ethyl, amino-substituted n-propyl, amino-substituted isopropyl, amino-substituted n-butyl, amino-substituted isobutyl, amino-substituted tert-butyl, amino-substituted n-pentyl, amino-substituted isopentyl, amino-substituted neopentyl, etc.

[0037] In this disclosure, "alkoxy groups having 1 to 12 carbon atoms" includes alkoxy groups having 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, or 12 carbon atoms, and specific examples include, but are not limited to, methoxy, ethoxy, and propoxy groups.

[0038] In this disclosure, the number of carbon atoms in "substituted or unsubstituted phenyl with 6 to 12 carbon atoms" includes the total number of carbon atoms of the phenyl group and the substituents on the phenyl group, which can be 6, 7, 8, 9, 10, 11, or 12. Specific examples include, but are not limited to, phenyl, benzyl, phenethyl, etc.

[0039] In this disclosure, the number of carbon atoms in "heterocyclic groups having 2 to 10 carbon atoms" can be 2, 3, 4, 5, 6, 7, 8, 9, or 10, and specific examples include, but are not limited to, those mentioned above. , , , , , , , wait.

[0040] In this disclosure, "alkylene" refers to a divalent or polyvalent group formed by the further loss of one or more H atoms from an alkyl group, and "alkoxide" has a similar definition.

[0041] In this disclosure, "substituted alkyl" means that at least one H on an alkyl group is substituted by a substituent; "substituted alkeneoxy", "substituted phenyl", and "substituted phenoxy" have similar definitions.

[0042] In this disclosure, the connection methods of R1, R2 and adjacent groups are conventional in the art. For example, R1 is ethylene, and its connection methods include: , , .

[0043] According to one embodiment of this disclosure, the substituents on the phenyl and phenoxy groups are located at the para position.

[0044] According to one embodiment of this disclosure, a1, a2, a3 and a4 may be the same or different, b1, b2, b3 and b4 may be the same or different, and (b1+b2+b3+b4):(a1+a2+a3+a4) = (0.5~5):1.

[0045] According to one embodiment of this disclosure, the weight-average molecular weight of the water-containing crude oil demulsifier is 1000~10000, preferably 2000~5000. When the weight-average molecular weight of the water-containing crude oil demulsifier is within the above range, it can avoid the disadvantages of low molecular weight leading to a high proportion of hydrophobic groups, decreased hydrophilicity, and poor water solubility, as well as high molecular weight leading to poor penetration ability and difficulty in penetrating into the extra-heavy oil phase to fully contact the polar components in the heavy oil, thereby achieving an enhanced demulsification effect.

[0046] In order to enable the demulsifier to reach the oil-water interface more quickly, promote droplet aggregation and interfacial film rupture, and achieve rapid demulsification and dehydration, according to one embodiment of the present disclosure, R1 and R2 may be the same or different, and are respectively selected from alkylene groups having 1 to 6 carbon atoms, and R3 is selected from heterocyclic groups having 3 to 9 carbon atoms, wherein the heterocyclic group contains N atoms.

[0047] According to a preferred embodiment of this disclosure, R3 is selected from the group consisting of: , , , , , , , .

[0048] According to one embodiment of this disclosure, each R4 may be the same or different, and is selected from alkyl groups having 4 to 8 carbon atoms.

[0049] A second aspect of this disclosure provides a method for preparing a demulsifier for water-containing crude oil, the method comprising: S1. A polyamine having the structure shown in Formula II is contacted with an epoxide having the structure shown in Formula III to carry out a first reaction, thereby obtaining a first intermediate. S2. The first intermediate is contacted with propylene oxide to carry out a second reaction, thereby obtaining a second intermediate; S3. The second intermediate is brought into contact with ethylene oxide to carry out the third reaction;

[0050] Formula II;

[0051] Formula III; Wherein, R1 and R2 may be the same or different, and are respectively selected from alkylene groups with 1 to 6 carbon atoms and alkene groups with 1 to 6 carbon atoms; R3 is selected from H, substituted or unsubstituted alkyl groups with 1 to 12 carbon atoms, alkoxy groups with 1 to 12 carbon atoms, substituted or unsubstituted phenyl groups with 6 to 12 carbon atoms, substituted or unsubstituted phenoxy groups, and heterocyclic groups with 2 to 10 carbon atoms. The substituents on the alkyl group include amino groups; The substituents on the phenyl group include alkyl groups having 1 to 6 carbon atoms; The substituents on the phenoxy group include alkyl groups having 1 to 6 carbon atoms; The heterocyclic group contains one or more of N, O and S atoms; Each R4 may be the same or different, and is selected from phenyl and alkyl groups having 1 to 12 carbon atoms, respectively; The molar ratio of ethylene oxide to propylene oxide is (0.1~10):1.

[0052] According to one embodiment of this disclosure, steps S1 to S3 are performed under an inert atmosphere, which includes nitrogen and / or argon.

[0053] To promote contact between raw materials and thus the reaction, according to one embodiment of this disclosure, step S1 is carried out in the presence of a solvent, which includes one or more of a saturated monohydric alcohol with 1 to 3 carbon atoms and dichloromethane, preferably one or more of methanol, ethanol, isopropanol and dichloromethane; the total concentration of the polyamine and the epoxide is 10 to 60% by weight, preferably 20 to 50% by weight, relative to the total weight of the solvent, the polyamine and the epoxide.

[0054] To promote the reaction, according to one embodiment of this disclosure, in step S1, the molar ratio of the epoxide to the polyamine is (4~40):1; the conditions for the first reaction include: a time of 2~24h, preferably 4~6h; and a temperature of 60~150℃, preferably 105~135℃.

[0055] According to one embodiment of this disclosure, the method further includes: after step S1, obtaining a first intermediate from the mixture obtained in step S1. Specifically, this can be achieved by removing the solvent using a rotary evaporator and then performing column chromatography. The specific operating methods and conditions are conventional in the art.

[0056] To promote the reaction, according to one embodiment of this disclosure, in step S2, the weight ratio of propylene oxide to the first intermediate is (1~10):1, preferably (1~5):1; the conditions for the second reaction include: time of 30~120 min, temperature of 105~125℃, and pressure of 0.3~1 MPa; the second reaction is carried out in the presence of an alkali, which includes sodium hydroxide and / or potassium hydroxide; the weight ratio of the alkali to the first intermediate is (0.25~1):100; the "reaction time" is calculated from the end of the propylene oxide addition.

[0057] According to one embodiment of this disclosure, the method further includes: continuing aging for 0.5 to 6 hours after the second reaction is completed.

[0058] According to one embodiment of this disclosure, in step S3, the conditions for the third reaction include: a time of 30-120 min and a temperature of 105-125 °C; the molar ratio of ethylene oxide to propylene oxide is (0.5-5):1; and the "reaction time" refers to the time calculated from the end of the ethylene oxide drop addition.

[0059] According to one embodiment of this disclosure, steps S2 and S3 can be carried out in a high-pressure reactor, and propylene oxide and ethylene oxide are added dropwise.

[0060] According to one embodiment of this disclosure, steps S2 and S3 are performed under stirring conditions, which are conventional in the art.

[0061] According to one embodiment of this disclosure, the method further includes: after step S3, neutralizing the mixture obtained from the third reaction with acetic acid and allowing it to stand and separate into layers.

[0062] The third aspect of this disclosure provides a demulsifier for water-containing crude oil prepared using the method described in the second aspect of this disclosure.

[0063] The demulsifier for water-containing crude oil described in the third aspect of this disclosure has the same characteristics as the demulsifier for water-containing crude oil described in the second aspect of this disclosure, and will not be described again here.

[0064] The fourth aspect of this disclosure provides a method for demulsifying water-containing crude oil, wherein the water-containing crude oil is contacted with the water-containing crude oil demulsifier described in the first or third aspect of this disclosure.

[0065] According to one embodiment of this disclosure, the water-containing crude oil includes water-containing heavy oil, preferably extra-heavy oil, wherein the viscosity of the water-containing heavy oil at 50°C is 2000~100000 mPa·s, preferably 5000~50000 mPa·s; and the water content is 10~85% by weight, preferably 10~80% by weight.

[0066] According to one embodiment of this disclosure, the contact includes: mixing the aqueous crude oil with a solution containing the aqueous crude oil demulsifier and then allowing it to stand; the contact temperature is 20~80℃, and the standing time is 30~240min; in the aqueous crude oil demulsifier solution, the concentration of the aqueous crude oil demulsifier is 0.001%~0.5% by weight; the amount of the aqueous crude oil demulsifier relative to 1L of the aqueous crude oil is 1.25~1000mg; the water used to prepare the solution can be oilfield formation produced water, tap water, or distilled water, preferably oilfield formation produced water.

[0067] The present disclosure is further illustrated by the following examples, but the present disclosure is not limited thereto. Unless otherwise specified, the raw materials, reagents, instruments, and equipment designed in the examples of this disclosure can all be obtained by purchase.

[0068] Example 1 Demulsifier A1 was prepared using the following steps:

[0069] (1) In a nitrogen atmosphere, 2.04 g (10.0 mmol) of diamine monomer (1-I) was added to a solution of 7.68 g (60.0 mmol) of 1,2-epoxyoctane in anhydrous ethanol (50 mL), and the mixture was heated to 100 °C and refluxed for 6 h. The total concentration of diamine monomer (1-I) and 1,2-epoxyoctane is 19.8% by weight, and the molar ratio of 1,2-epoxyoctane to diamine monomer (1-I) is 6:1. After the reaction was completed, the anhydrous ethanol solvent was removed by rotary evaporation, the crude product was dissolved in dichloromethane, and then purified by elution with dichloromethane / methanol using a silica gel column and vacuum drying to obtain 9.2 g of white powdery first intermediate (1-II), with a yield of 94.6%.

[0070] (2) Add 9g of the first intermediate (1-II) to the high-pressure reactor, then add 0.05g of KOH catalyst, seal the reactor body, and use dry nitrogen to displace the air in the high-pressure reactor, feed vessel, and feed pipe. Start heating and stirring, and simultaneously use a vacuum pump to evacuate the system. Stop evacuating the system when the temperature reaches 100℃, pressurize to 0.4MPa, start mechanical stirring, and then open the feed valve to slowly add propylene oxide. The total amount of propylene oxide added is 14g. During the process, control the reaction temperature at 115℃ and the pressure at 0.4MPa. After the addition is complete, stop stirring after reacting for 1 hour and continue aging for 1 hour. The weight ratio of propylene oxide to the first intermediate (1-II) is 1.56:1; The weight ratio of potassium hydroxide to the first intermediate (1-II) is 0.56:100.

[0071] (3) While stirring, continue to add ethylene oxide dropwise to the reactor in (2). The total amount of ethylene oxide is 7g, the temperature is 115℃, and the reaction time is 60 min. After the reaction is completed, wait for the pressure inside the reactor to drop to a constant value, then cool and discharge the product. Neutralize the reaction product with acetic acid, and after standing and separating into layers, take the lower opaque layer to obtain 27.3g, with a yield of 91%. The molar ratio of ethylene oxide to propylene oxide is 1.5:1.

[0072] The weight-average molecular weight of demulsifier A1 was determined to be 2100 using GPC.

[0073] Based on the feed amounts of propylene oxide and ethylene oxide and the stoichiometry, the ratio of (b1+b2+b3+b4):(a1+a2+a3+a4) in demulsifier A1 is 1.5:1.

[0074] The demulsifier A1 was subjected to carbon NMR spectroscopy, and the results are listed below. Figure 1 .according to Figure 1 As shown, the carbon spectrum at shift 173 is the carbon spectrum of the carbon atom between two nitrogen atoms in the nitrogen-containing heterocycle; shifts at 146, 143, and 131 are the carbon spectra of the carbon atoms on the benzene ring; shifts between 60 and 100 are the carbon spectra of the carbon atoms in epoxide, ethylene oxide, and propylene oxide; and shifts below 60 are the carbon spectra of the carbon atoms in the alkyl chain.

[0075] Example 2 Demulsifier A2 was prepared using the following steps:

[0076] (1) In a nitrogen atmosphere, 2.52 g (10.0 mmol) of diamine monomer (2-I) was added to a solution of 7.68 g (60.0 mmol) of 1,2-epoxyoctane in anhydrous ethanol (50 mL), and the mixture was heated to 100 °C and refluxed for 6 h. The total concentration of diamine monomer (2-I) and 1,2-epoxyoctane is 20.5% by weight, and the molar ratio of 1,2-epoxyoctane to diamine monomer (2-I) is 6:1. After the reaction was completed, the anhydrous ethanol solvent was removed by rotary evaporation, the crude product was dissolved in dichloromethane, and then purified by elution with dichloromethane / methanol on a silica gel column and vacuum dried to obtain 9.3 g of white powdery first intermediate (2-II), with a yield of 91.2%.

[0077] (2) Add 6g of the first intermediate (2-II) to the high-pressure reactor, then add 0.05g of KOH catalyst, seal the reactor body, and use dry nitrogen to displace the air in the high-pressure reactor, feed vessel, and feed pipe. Start heating and stirring, and simultaneously use a vacuum pump to evacuate the system. Stop evacuating the system when the temperature reaches 100℃, pressurize to 0.4MPa, start mechanical stirring, and then open the feed valve to slowly add propylene oxide. The total amount of propylene oxide added is 12g. During the process, control the reaction temperature at 115℃ and the pressure at 0.4MPa. After the addition is complete, stop stirring after reacting for 1 hour and continue aging for 1 hour. The weight ratio of propylene oxide to the first intermediate (2-II) is 2:1; The weight ratio of potassium hydroxide to the first intermediate (2-II) is 0.83:100.

[0078] (3) While stirring, continue to add ethylene oxide dropwise to the reactor in (2). The total amount of ethylene oxide is 7g, the temperature is 115℃, and the reaction time is 60 min. After the reaction is completed, wait for the pressure inside the reactor to drop to a constant value, then cool and discharge the product. Neutralize the reaction product with acetic acid, and after standing and separating the layers, take the lower opaque layer to obtain 23.9g, with a yield of 95.5%. The molar ratio of ethylene oxide to propylene oxide is 1.3:1.

[0079] The weight-average molecular weight of demulsifier A2 was determined to be 3600 using GPC.

[0080] Based on the feed amounts of propylene oxide and ethylene oxide and the stoichiometry, the ratio of (b1+b2+b3+b4):(a1+a2+a3+a4) in demulsifier A2 is 1.3:1.

[0081] The demulsifier A2 was subjected to carbon NMR spectroscopy, and the results are listed below. Figure 2 ,according to Figure 2 The data shows that the carbon spectrum at shift 330 represents the carbon atom connected to both nitrogen and benzene rings; at shift 159 represents the carbon atom between two nitrogen atoms in a nitrogen-containing heterocycle; shifts 153 and 147 represent the carbon spectra of carbon atoms on the benzene ring in benzopyrazole; shifts 135, 137, and 149 represent the carbon spectra of carbon atoms on the benzene ring; shifts between 60 and 90 represent the carbon spectra of octane oxide, ethylene oxide, and propylene oxide; and shifts below 60 represent the carbon spectra of carbon atoms in alkyl chains.

[0082] Example 3 Demulsifier A3 was prepared using the following steps:

[0083] (1) In a nitrogen atmosphere, 2.23 g (10.0 mmol) of diamine monomer (3-I) was added to a solution of 9.38 g (60.0 mmol) of 1,2-epoxydecane in anhydrous ethanol (50 mL), and the mixture was heated to 100 °C and refluxed for 6 h. The total concentration of diamine monomer (3-I) and 1,2-epoxydecane was 22.7% by weight, and the molar ratio of 1,2-epoxydecane to diamine monomer (3-I) was 6:1. After the reaction was completed, the anhydrous ethanol solvent was removed by rotary evaporation, the crude product was dissolved in dichloromethane, and then purified by elution with dichloromethane / methanol on a silica gel column and vacuum dried to obtain 10.3 g of white powdery first intermediate (3-II), with a yield of 88.7%.

[0084] (2) Add 6g of the first intermediate (3-II) to the high-pressure reactor, then add 0.05g of KOH catalyst, seal the reactor body, and use dry nitrogen to displace the air in the high-pressure reactor, feed vessel, and feed pipe. Start heating and stirring, and simultaneously use a vacuum pump to evacuate the system. Stop evacuating the system when the temperature reaches 100℃, pressurize to 0.4MPa, start mechanical stirring, and then open the feed valve to slowly add propylene oxide. The total amount of propylene oxide added is 14g. During the process, control the reaction temperature at 115℃ and the pressure at 0.4MPa. After the addition is complete, stop stirring after reacting for 1 hour and continue aging for 1 hour. The weight ratio of propylene oxide to the first intermediate (3-II) is 2.33:1; The weight ratio of potassium hydroxide to the first intermediate (3-II) is 0.83:100.

[0085] (3) While stirring, ethylene oxide was added dropwise to the reactor in (2). The total amount of ethylene oxide was 7g, the temperature was 115℃, and the reaction time was 60 min. After the reaction was completed, the pressure inside the reactor was allowed to drop to a constant value, and the product was cooled and discharged. The reaction product was neutralized with acetic acid, and after standing and separating into layers, the lower opaque layer was taken to obtain 27.8g, with a yield of 95.9%. The molar ratio of ethylene oxide to propylene oxide is 1.5:1.

[0086] The weight-average molecular weight of demulsifier A3 was determined to be 5000 using GPC.

[0087] Based on the feed amounts of propylene oxide and ethylene oxide and the stoichiometry, the ratio of (b1+b2+b3+b4):(a1+a2+a3+a4) in demulsifier A3 is 1.5:1.

[0088] The demulsifier A3 was subjected to carbon NMR spectroscopy, and the results are listed below. Figure 3 , Figure 3 This indicates that it has the target structure shown in the figure above.

[0089] Example 4 Demulsifier A4 was prepared using the following steps:

[0090] (1) In a nitrogen atmosphere, 2.04 g (10.0 mmol) of diamine monomer (4-I) was added to a solution of 9.38 g (60.0 mmol) of 1,2-epoxydecane in anhydrous ethanol (50 mL), and the mixture was heated to 100 °C and refluxed for 6 h. The total concentration of diamine monomer (4-I) and 1,2-epoxydecane was 22.4% by weight, and the molar ratio of 1,2-epoxydecane to diamine monomer (4-I) was 6:1. After the reaction was completed, the anhydrous ethanol solvent was removed by rotary evaporation, the crude product was dissolved in dichloromethane, and then purified by elution with dichloromethane / methanol using a silica gel column and vacuum drying to obtain 9.2 g of white powdery first intermediate (1-II), with a yield of 94.6%.

[0091] (2) Add 6g of the first intermediate (1-II) to the high-pressure reactor, then add 0.05g of KOH catalyst, seal the reactor body, and use dry nitrogen to displace the air in the high-pressure reactor, feed vessel, and feed pipe. Start heating and stirring, and simultaneously use a vacuum pump to evacuate the system. Stop evacuating the system when the temperature reaches 100℃, pressurize to 0.4MPa, start mechanical stirring, and then open the feed valve to slowly add propylene oxide. The total amount of propylene oxide added is 14g. During the process, control the reaction temperature at 115℃ and the pressure at 0.4MPa. After the addition is complete, stop stirring after reacting for 1 hour and continue aging for 1 hour. The weight ratio of propylene oxide to the first intermediate (1-II) is 2.33:1; The weight ratio of potassium hydroxide to the first intermediate (1-II) is 0.83:100.

[0092] (3) While stirring, continue to add ethylene oxide dropwise to the reactor in (2). The total amount of ethylene oxide is 7g, the temperature is 115℃, and the reaction time is 60 min. After the reaction is completed, wait for the pressure inside the reactor to drop to a constant value, then cool and discharge the product. Neutralize the reaction product with acetic acid, and after standing and separating into layers, take the lower opaque layer to obtain 27.3g, with a yield of 91%. The molar ratio of ethylene oxide to propylene oxide is 1.5:1.

[0093] The weight-average molecular weight of demulsifier A4 was determined to be 3900 using GPC.

[0094] Based on the feed amounts of propylene oxide and ethylene oxide and the stoichiometry, the ratio of (b1+b2+b3+b4):(a1+a2+a3+a4) in demulsifier A4 is 1.5:1.

[0095] The demulsifier A4 was subjected to carbon NMR spectroscopy, and the results are listed below. Figure 4 , Figure 4 This indicates that it has the target structure shown in the figure above.

[0096] Test Example 1: Interfacial Activity and Critical Aggregation Concentration The oil-water interfacial tension of the polymeric demulsifier prepared in the examples was measured using a TX-500C interfacial tensiometer with the rotating droplet method. The oil used in the experiment was a produced oil sample from an oilfield in Northwest China, with a viscosity of 12500 mPa·s at 50°C. The test temperature was controlled at 50°C and the rotation speed at 5000 rpm.

[0097] During the experiment, as the surfactant concentration increased, the oil-water interfacial tension continuously decreased. After a certain critical concentration, the interfacial tension remained relatively stable, resulting in a plateau region. This critical concentration was defined as the critical aggregation concentration (CAC), and the interfacial tension value in the plateau region was defined as the interfacial tension. The test parameters are listed in Table 1.

[0098] Test Example 2: Demulsification and Dehydration Performance Test of Polymer Demulsifier The oil used in the experiment was crude oil from an oil field in Xinjiang. Its viscosity at 50℃ was 12250 mPa•s, which falls into the category of extra-heavy oil. According to the crude oil water content test method (GB / T8929), its water content was measured to be 58.7% by weight.

[0099] The demulsifiers prepared in Examples 1-4 were prepared into a 1% by weight solution using tap water and then put into use.

[0100] Take 99 mL of the above-mentioned water-containing crude oil and add it to a graduated 100 mL test tube. Add the polymeric demulsifier prepared in Test Examples 1-4. The amount of demulsifier used is 100 mg relative to 1 L of water-containing crude oil. After treating at 50 °C for 60 min, determine the oil phase content and water phase content in the test tube. At the same time, extract the water phase separated from the bottom of the test tube and determine the oil content in the water phase according to SY / T0530. Determine the water content in the oil phase in the upper part of the test tube according to the method described in GB / T8929.

[0101] Following the same method, the amount of water removed, the oil content in the aqueous phase, and the water content in the upper oil phase were tested after treatment at 30℃ and 80℃ for 60 minutes.

[0102] Comparative Example 1 The same method as in Test Example 2 was used, except that the demulsifier was replaced with an equal volume of water. The results are shown in Table 1.

[0103] Comparative Example 2 The same method as in Test Example 2 was used, except that the demulsifier was replaced with an equal volume of the commercially available demulsifier product nonylphenol polyoxyethylene ether (molecular weight 880). The results are listed in Table 1.

[0104] Table 1

[0105] According to the test data in Table 1, the demulsifier disclosed herein can significantly reduce interfacial tension in high-calcium, high-magnesium, and high-salinity formation water, demonstrating significantly better interfacial activity than the comparative commercial demulsifiers. Simultaneously, it can effectively disrupt the W / O stable emulsion system in heavy oil, achieving oil-water separation. At 50°C and above, the dehydration rate reaches over 90%, and at a lower temperature of 30°C, the dehydration rate reaches over 85%. In contrast, at lower temperatures of 50°C and below, the commercially available demulsifier AE exhibits a lower dehydration rate in heavy oil, less than 30%, and is difficult to effectively remove water at low temperatures.

[0106] The preferred embodiments of this disclosure have been described in detail above with reference to the accompanying drawings. However, this disclosure is not limited to the specific details of the above embodiments. Within the scope of the technical concept of this disclosure, various simple modifications can be made to the technical solutions of this disclosure, and these simple modifications all fall within the protection scope of this disclosure.

[0107] It should also be noted that the various specific technical features described in the above embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, this disclosure will not describe the various possible combinations separately.

[0108] Furthermore, various different embodiments of this disclosure can be combined in any way, as long as they do not violate the spirit of this disclosure, they should also be regarded as the content disclosed in this disclosure.

Claims

1. An aqueous crude oil demulsifier, characterized in that, The aqueous crude oil demulsifier comprises a polymer having a structure shown in Formula I: Formula I wherein R1 and R2 are the same or different, and are selected from alkylene groups having 1 to 6 carbon atoms, and alkylene oxide groups having 1 to 6 carbon atoms, respectively; R3 is selected from H, substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, substituted or unsubstituted phenyl groups having 6 to 12 carbon atoms, substituted or unsubstituted phenoxy groups, and heterocyclic groups having 2 to 10 carbon atoms; the substituents on the alkyl groups include amino groups; the substituents on the phenyl groups include alkyl groups having 1 to 6 carbon atoms; the substituents on the phenoxy groups include alkyl groups having 1 to 6 carbon atoms; the heterocyclic groups contain one or more of N atoms, O atoms, and S atoms; each R4 is the same or different, and is selected from phenyl groups and alkyl groups having 1 to 12 carbon atoms; a1, a2, a3, and a4 are the same or different, b1, b2, b3, and b4 are the same or different, and (b1+b2+b3+b4):(a1+a2+a3+a4)=(0.1-10):

1.

2. The aqueous crude oil demulsifier of claim 1, wherein, The aqueous crude oil demulsifier has a weight average molecular weight of 1000-10000, preferably 2000-5000.

3. The aqueous crude oil demulsifier of claim 1, wherein, R3 is selected from heterocyclic groups having 3 to 9 carbon atoms, the heterocyclic groups containing N atoms; Preferably, R3 is selected from the group consisting of: 、 、 、 、 、 、 、 。 4. The aqueous crude oil demulsifier of claim 1, wherein, each R4 is the same or different, and is selected from alkyl groups having 4 to 8 carbon atoms.

5. Process for the preparation of an aqueous crude oil demulsifier, characterized in that, The method comprises: S1, contacting a polyamine having a structure shown in Formula II with an alkylene oxide having a structure shown in Formula III to perform a first reaction to obtain a first intermediate; S2, contacting the first intermediate with propylene oxide to perform a second reaction to obtain a second intermediate; S3, contacting the second intermediate with ethylene oxide to perform a third reaction; Formula II; Formula III; wherein R1 and R2 are the same or different, and are selected from alkylene groups having 1 to 6 carbon atoms, and alkylene oxide groups having 1 to 6 carbon atoms, respectively; R3 is selected from H, substituted or unsubstituted alkyl groups having 1 to 12 carbon atoms, alkoxy groups having 1 to 12 carbon atoms, substituted or unsubstituted phenyl groups having 6 to 12 carbon atoms, substituted or unsubstituted phenoxy groups, and heterocyclic groups having 2 to 10 carbon atoms; the substituents on the alkyl groups include amino groups; the substituents on the phenyl groups include alkyl groups having 1 to 6 carbon atoms; the substituents on the phenoxy groups include alkyl groups having 1 to 6 carbon atoms; the heterocyclic groups contain one or more of N atoms, O atoms, and S atoms; each R4 is the same or different, and is selected from phenyl groups and alkyl groups having 1 to 12 carbon atoms; the molar ratio of the ethylene oxide to the propylene oxide is (0.1-10):

1.

6. The method of claim 5, wherein, R3 is selected from heterocyclic groups having 3 to 9 carbon atoms, the heterocyclic groups containing N atoms; Preferably, R3 is selected from the group consisting of: 、 、 、 、 、 、 、 ； each R4 is the same or different, and is selected from alkyl groups having 4 to 8 carbon atoms.

7. The method of claim 5, wherein, Steps S1 to S3 are performed under an inert atmosphere, the inert atmosphere including nitrogen and / or argon.

8. The method of claim 5, wherein, The step S1 is carried out in the presence of a solvent, which includes one or more of saturated monohydric alcohols having 1-3 carbon atoms and dichloromethane; The total concentration of the polyamine and the alkylene oxide is 10-60 wt%, preferably 20-50 wt%, relative to the total weight of the solvent, the polyamine and the alkylene oxide.

9. The method of claim 5, wherein, In the step S1, the molar ratio of the alkylene oxide to the polyamine is (4-40):

1. The conditions of the first reaction include a time of 2-24 h and a temperature of 60-150℃.

10. The method of claim 5, wherein, In the step S2, the weight ratio of the propylene oxide to the first intermediate is (1-10):1, preferably (1-5):

1. The conditions of the second reaction include a time of 30-120 min, a temperature of 105-125℃ and a pressure of 0.3-1 MPa. The second reaction is carried out in the presence of a base, which includes sodium hydroxide and / or potassium hydroxide. The weight ratio of the base to the first intermediate is (0.25-1):

100.

11. The method of claim 5, wherein, In the step S3, the conditions of the third reaction include a time of 30-120 min and a temperature of 105-125℃. The molar ratio of the ethylene oxide to the propylene oxide is (0.5-5):

1.

12. An aqueous crude oil demulsifier prepared by the method of any one of claims 5-11.

13. A method for demulsification of water-containing crude oil, characterized in that, The aqueous crude oil is contacted with the aqueous crude oil demulsifier of any one of claims 1-4 and 12.

14. The method of claim 13, wherein, The aqueous crude oil includes an aqueous viscous crude oil having a viscosity of 2000-100000 mPa·s at 50℃ and a water content of 10-85 wt%.

15. The method of claim 13, wherein, The contacting includes mixing the aqueous crude oil with a solution containing the aqueous crude oil demulsifier and then standing; The temperature of the contacting is 20-80℃ and the standing time is 30-240 min. In the solution of the aqueous crude oil demulsifier, the concentration of the aqueous crude oil demulsifier is 0.001-0.5 wt%; The amount of the aqueous crude oil demulsifier is 1.25-1000 mg per 1 L of the aqueous crude oil.

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