A microemulsion demulsifier, its preparation method and application

Abstract

This invention discloses a microemulsion demulsifier, its preparation method, and its application. The microemulsion demulsifier comprises a polyether-type demulsifier and an acrylate copolymer. The microemulsion demulsifier is polymerized from microemulsions and has a particle size of 10–100 nm. Its small particle radius and large surface area result in strong wetting properties and penetration effects. The microemulsion demulsifier significantly improves the demulsification and dehydration rate, enhancing its demulsification and dehydration performance on crude oil emulsions.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemicals technology, and more specifically, to a microemulsion demulsifier, its preparation method, and its application. Background Technology

[0002] During oil extraction and processing, the gums, asphalt, naphthenic acids, fatty acids and salts, crystalline paraffins, and various artificially introduced surface-active substances in crude oil often result in a water-in-oil or oil-in-water emulsion state. These oil-water emulsions present a series of problems for crude oil storage, transportation, and processing. Crude oil demulsifiers are surfactants that can disrupt emulsions. Their molecules contain both lipophilic and hydrophilic groups; when added to a crude oil emulsion, the resulting emulsion breakdown is called chemical demulsification. Research and application of first-generation crude oil demulsifiers began in the 1920s, primarily using anionic surfactants. Second-generation crude oil demulsifiers were developed after the 1940s. From the 1960s to the present, third-generation crude oil demulsifiers, mainly using high-molecular-weight nonionic surfactants, have been researched and applied. After 1990, amphoteric surfactants were successfully researched and entered the practical application stage. Since the late 1980s, research and development of demulsifiers abroad (mainly in the United States) has been rapid. Based on the improvement of third-generation polyether demulsifiers with high relative molecular mass, a large number of new demulsifier products have been researched and developed, and significant progress has been made.

[0003] However, with the application of tertiary oil recovery technology and heavy oil extraction technology, demulsifiers, in addition to meeting the basic requirements of traditional demulsifiers, must also meet the requirements of dehydration processes under rapid, efficient, and low-temperature conditions. Therefore, the research on rapid and efficient demulsifiers is of great necessity.

[0004] Microemulsion polymerization is an emulsion polymerization process for preparing small-particle-size latex. A microemulsion system is a thermodynamically stable, transparent dispersion of two incompatible components. Microemulsions have particle sizes within 100 nm, characterized by small radii and large surface areas, resulting in unsaturation and exhibiting strong chemical and adsorption properties. Due to the unique properties of nanomaterials, nano-demulsifiers based on oil-water separation have attracted considerable attention in the petroleum industry. Summary of the Invention

[0005] The technical problem to be solved by this invention is to address the shortcomings of the prior art by providing a microemulsion demulsifier, its preparation method, and its application. This demulsifier mainly comprises a polyether-type demulsifier and an acrylate copolymer, and is formed by microemulsion polymerization. The microemulsion has a particle size within 100 nm, a small particle radius, and a large surface area, exhibiting strong wetting properties and penetration effects, allowing it to quickly reach the oil-water interface. Furthermore, the acrylate copolymer and the polyether-type demulsifier each possess their own demulsification characteristics; their synergistic effect significantly improves the demulsification and dehydration rate, thereby enhancing the demulsification and dehydration performance of the demulsifier on crude oil emulsions.

[0006] One of the objectives of this invention is to provide a microemulsion demulsifier, comprising a polyether-type demulsifier and an acrylate copolymer.

[0007] According to a preferred embodiment of the present invention, the polyether-type demulsifier is a water-soluble polyether demulsifier, preferably a block polyether with an alcohol as an initiator.

[0008] According to a preferred embodiment of the present invention, the acrylate copolymer is a copolymer polymerized from hydrophobic monomers, hydrophilic monomers, and optionally crosslinking monomers.

[0009] The hydrophobic monomer is preferably selected from at least one of styrene, methacrylate compounds, and acrylate compounds, and more preferably from one, two, or more of methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, ethylhexyl acrylate, isooctyl methacrylate, lauryl acrylate, lauryl methacrylate, octadecyl acrylate, and octadecyl methacrylate.

[0010] The hydrophilic monomer is preferably selected from at least one of acrylic compounds and polyethers with double bonds at the end groups, more preferably from at least one of acrylic compounds and polyoxyethylene ethers with double bonds at the end groups, and most preferably selected from one, two or more of acrylic acid, allyl polyoxyethylene ether, and polyethylene glycol monomethyl ether acrylate.

[0011] The crosslinking monomer is preferably an olefin containing two or more unsaturated double bonds, and more preferably one, two or more of the following: diethylene glycol dimethacrylate, trimethylolpropionic acid triacrylate, butanediol dimethacrylate, divinylbenzene, butanediol diacrylate, N-hydroxymethylacrylamide, and N,N'-methylenebisacrylamide.

[0012] The particle size of the microemulsion demulsifier can be 10-100 nm, preferably 30-80 nm.

[0013] A second objective of this invention is to provide a method for preparing the demulsifier, comprising microemulsion polymerization of raw materials including hydrophobic monomers, hydrophilic monomers, polyether-type demulsifiers, co-emulsifiers, initiators, and optional crosslinking monomers.

[0014] According to a preferred embodiment of the present invention, the preparation method includes: mixing a co-emulsifier and a polyether-type demulsifier evenly, adding water, a hydrophobic monomer, and optionally a crosslinking monomer, preferably heating to 30-80°C, adding a portion of an initiator under a nitrogen atmosphere, preferably reacting for 3-5 hours, then adding a hydrophilic monomer and the remaining initiator, preferably maintaining the temperature for 2-5 hours, and then cooling to room temperature to obtain a microemulsion demulsifier.

[0015] In the above preparation method, the hydrophilic monomer can be added last; alternatively, some of the hydrophilic monomer can be added together with the hydrophobic monomer, and the remaining hydrophilic monomer can be added last.

[0016] In the above preparation method, the initiator is prepared into an aqueous solution and then added dropwise to the reaction system.

[0017] In the above preparation method, the preferred time for adding the hydrophilic monomer and the remaining initiator aqueous solution is 30 to 60 minutes.

[0018] In a specific embodiment of the present invention, the hydrophobic monomer may be selected from one, two or more of styrene, methacrylate compounds, and acrylate compounds, preferably at least one of methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, isooctyl methacrylate, ethylhexyl acrylate, lauryl acrylate, lauryl methacrylate, octadecyl acrylate and octadecyl methacrylate.

[0019] In a specific embodiment of the present invention, the hydrophilic monomer may be selected from one or two of acrylic compounds and polyether monomers with double bonds at the end group; preferably at least one of acrylic compounds and polyoxyethylene ether monomers with double bonds at the end group; more preferably at least one of acrylic acid, allyl polyoxyethylene ether or polyethylene glycol monomethyl ether acrylate.

[0020] The weight ratio of the hydrophilic monomer to the hydrophobic monomer is (5:95) to (50:50), preferably (5:95) to (40:60), and can specifically be 5:95, 10:90, 15:85, 20:80, 25:75, 30:70, 35:65, 40:60, 45:55, 50:50, etc.

[0021] According to a specific embodiment of the present invention, the crosslinking monomer may be selected from olefins containing two or more unsaturated double bonds, preferably at least one of diethylene glycol dimethacrylate, trimethylolpropionic acid triacrylate, butanediol dimethacrylate, divinylbenzene, butanediol diacrylate, N-hydroxymethylacrylamide, and N,N'-methylenebisacrylamide.

[0022] The crosslinking monomer is used in an amount of 0 to 3 wt% of the total amount of the hydrophilic monomer and the hydrophobic monomer, by weight. Preferably, the crosslinking monomer is used in an amount of 0.001 wt% to 0.3 wt% of the total amount of the hydrophilic monomer and the hydrophobic monomer, more preferably 0.001 wt% to 0.1 wt%, specifically 0.001 wt%, 0.005 wt%, 0.01 wt%, 0.03 wt%, 0.05 wt%, 0.08 wt%, 0.1 wt%, 0.5 wt%, 1 wt%, 2 wt%, 3 wt%, etc.

[0023] The polyether-type demulsifier serves as an emulsifier. The polyether-type demulsifier can be a water-soluble polyether demulsifier dry form, preferably a block polyether with an alcohol initiator.

[0024] The amount of the polyether-type demulsifier by weight is 0.25 to 5 times the total amount of the hydrophilic monomer and the hydrophobic monomer, preferably 0.5 to 3 times, and specifically can be 0.25 times, 0.5 times, 1 time, 2 times, 3 times, 4 times, 5 times, etc.

[0025] According to a preferred embodiment of the present invention, the co-emulsifier is an organic alcohol, preferably at least one selected from methanol, ethanol, isopropanol, tert-butanol, n-octanol and dodecanol, and more preferably methanol and ethanol.

[0026] The amount of the co-emulsifier by weight is 0.25 to 5 times the total amount of the hydrophilic monomer and the hydrophobic monomer, preferably 0.5 to 3 times, and specifically can be 0.25 times, 0.5 times, 1 time, 2 times, 3 times, 4 times, 5 times, etc.

[0027] According to a preferred embodiment of the present invention, the initiator is selected from redox initiators and / or azo initiators.

[0028] Preferably, the redox initiator is selected from ammonium persulfate-sodium bisulfite and potassium persulfate-sodium bisulfite, and the azo initiator is selected from one or more of dimethyl 2,2-azobisisobutyrate, 2,2-azo[2-(2-imidazolinyl)propane]dihydrochloride, azobisisobutyramidine hydrochloride, and azobisisobutyramidine hydrochloride.

[0029] The amount of the initiator is 0.1wt% to 2wt% of the total amount of the hydrophilic monomer and the hydrophobic monomer, preferably 0.3wt% to 1.5wt%, and can specifically be 0.1wt%, 0.2wt%, 0.3wt%, 0.4wt%, 0.5wt%, 0.6wt%, 0.7wt%, 0.8wt%, 0.9wt%, 1wt%, 1.2wt%, 1.5wt%, 2wt%, etc.

[0030] A third objective of this invention is to provide the application of the demulsifier or the demulsifier obtained by the preparation method in crude oil demulsification.

[0031] The demulsifier can be used alone or in combination with other demulsifiers known in the art.

[0032] The microemulsion demulsifier of the present invention has a small microemulsion particle size and a large surface area, which has strong wetting properties and penetration effect, and can quickly reach the oil-water interface. Furthermore, the acrylate copolymer and the polyether demulsifier have their own demulsification characteristics. The two work synergistically to greatly improve the demulsification and dehydration speed and improve the demulsification and dehydration performance of the demulsifier on crude oil emulsions. Attached Figure Description

[0033] Figure 1 The results are for particle size detection in Example 1.

[0034] Figure 2 The results are for particle size detection in Example 2.

[0035] Figure 3 The results are for particle size detection in Example 3. Detailed Implementation

[0036] The present invention will now be described in detail with reference to specific embodiments. It should be noted that the following embodiments are only used to further illustrate the present invention and should not be construed as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by those skilled in the art based on the content of the present invention are still within the scope of protection of the present invention.

[0037] It should also be noted that the various specific technical features described in the following embodiments can be combined in any suitable manner without contradiction. To avoid unnecessary repetition, the various possible combinations will not be described separately in this invention.

[0038] Furthermore, various embodiments of the present invention can be combined in any way, as long as they do not violate the spirit of the present invention. The resulting technical solutions are part of the original disclosure of this specification and also fall within the protection scope of the present invention.

[0039] Unless otherwise specified, the raw materials used in the examples and comparative examples are all disclosed in the prior art, such as those that can be directly purchased or prepared according to the preparation methods disclosed in the prior art.

[0040] According to a preferred embodiment of the present invention, the hydrophilic monomer includes an acrylic acid compound monomer and a polyether monomer with a double bond at the end group. The preparation method of the present invention may include the following steps:

[0041] Add all organic alcohol co-emulsifiers and water-soluble polyether demulsifier dry agent to the reactor, start stirring and mix evenly, add some distilled water, polyether monomers with double bonds at the end groups, hydrophobic monomers, and optional crosslinking monomers, heat to the reaction temperature, add some initiator aqueous solution dropwise under nitrogen atmosphere, react for 3-5 hours, add acrylic hydrophilic monomers and some initiator aqueous solution dropwise for 30-60 minutes, keep the reaction at the temperature for 2-5 hours, cool to room temperature, and discharge to obtain microemulsion demulsifier.

[0042] Example 1

[0043] Add 30 g of methanol and 15 g of polyether dry agent PE2040 (initiator is polyol) to a reactor, stir and mix thoroughly. Add 20 g of distilled water, 5 g of polyoxyethylene ether monomer (HPEG-2400) with double bonds at the end groups, 6 g of butyl acrylate, 4 g of methyl methacrylate, and 0.03 g of N,N'-methylenebisacrylamide. Heat to the reaction temperature of 50°C. Under a nitrogen atmosphere, add 12 g of 1% concentration of 2-azo(2-amidinylpropane) dihydrochloride (V50) aqueous solution dropwise over 30 min. Maintain the reaction temperature for 3 hours. Add 0.5 g of acrylic acid and 4 g of 1% concentration of 2-azo(2-amidinylpropane) dihydrochloride (V50) aqueous solution dropwise over 30 min. Maintain the reaction temperature for 4 hours, then cool to room temperature and discharge to obtain a microemulsion demulsifier. The microemulsion particle size is 66.1 nm.

[0044] Example 2

[0045] Add 30 g of methanol and 15 g of polyether dry agent PE2040 (initiator is polyol) to a reactor, stir and mix thoroughly. Add 20 g of distilled water, 5 g of polyoxyethylene ether monomer (HPEG-2400) with double bonds at the end groups, 6 g of butyl acrylate, 4 g of ethylhexyl acrylate, and 0.03 g of N,N'-methylenebisacrylamide. Heat to the reaction temperature of 50°C. Under a nitrogen atmosphere, add 12 g of 1% concentration of 2-azo(2-amidinylpropane) dihydrochloride (V50) aqueous solution dropwise over 30 min. Maintain the reaction temperature for 3 hours. Add 0.5 g of acrylic acid and 4 g of 1% concentration of 2-azo(2-amidinylpropane) dihydrochloride (V50) aqueous solution dropwise over 30 min. Maintain the reaction temperature for 4 hours, then cool to room temperature and discharge to obtain a microemulsion demulsifier. The microemulsion particle size is 46.8 nm.

[0046] Example 3

[0047] 49.5 g of methanol and 49.5 g of polyether dry agent PE2040 (initiator is polyol) were added to a reactor. The mixture was stirred until homogeneous. Then, 36 g of distilled water, 9 g of butyl acrylate, 6 g of methyl methacrylate, and 0.03 g of N,N'-methylenebisacrylamide were added. The temperature was raised to 50°C. Under a nitrogen atmosphere, 12 g of a 1% concentration of 2-azo(2-amidinylpropane) dihydrochloride (V50) aqueous solution was added dropwise over 30 min. The reaction was maintained at this temperature for 3 hours. Then, 1.5 g of acrylic acid and 4 g of a 1% concentration of 2-azo(2-amidinylpropane) dihydrochloride (V50) aqueous solution were added dropwise over 30 min. The reaction was maintained at this temperature for 4 hours. The mixture was then cooled to room temperature and discharged to obtain a microemulsion demulsifier. The microemulsion particle size was 75.5 nm.

[0048] Comparative Example 1

[0049] The demulsifier used at the Chengdong Joint Station of the Hekou Oil Production Plant in Shengli Oilfield is a polyoxyethylene polyoxypropylene ether with polyol as the initiator, provided by Shengli Chemical Hekou Branch.

[0050] Comparative Example 2

[0051] The demulsifier used at the Guliu Joint Station of the Hekou Gudao Oil Production Plant in Shengli Oilfield was adopted. This demulsifier is a polyoxyethylene polyoxypropylene ether with phenolic resin as the initiator, which was provided by Shengli Chemical Hekou Branch.

[0052] Example 4

[0053] The demulsifiers prepared in Examples 1-3 and Comparative Example 1 were used to evaluate the demulsification performance of crude oil from Chengdong, Shengli Oilfield. The evaluation method specified in the Petroleum and Natural Gas Industry Standard SY-T5281-2000, "Performance Testing Method for Crude Oil Demulsifiers (Bottle Test Method)," was used to evaluate their demulsification performance.

[0054] The specific demulsifying properties are shown in Table 1 below.

[0055] Table 1. Indoor Demulsification Performance Evaluation Experiment

[0056]

[0057] Experiments have shown that the microemulsion demulsifier prepared by the method of this invention has a significantly higher demulsification effect on the heavy oil emulsion at the Chengdong Joint Station than the demulsifier of Comparative Example 1 (i.e., the field-use demulsifier). Furthermore, at a dosage concentration of 80 mg / L, the demulsifier of Example 1 is superior to the demulsification effect of Comparative Example 1 at a dosage concentration of 100 mg / L.

[0058] Example 5

[0059] The demulsifiers prepared in Examples 1-3 and Comparative Example 2 were used to evaluate the demulsification performance of crude oil from Gudao Oilfield in Shengli Oilfield. The evaluation method specified in the Petroleum and Natural Gas Industry Standard SY-T5281-2000, "Performance Testing Method for Crude Oil Demulsifiers (Bottle Test Method)," was used to evaluate their demulsification performance.

[0060] The specific demulsification performance is shown in Table 2 below.

[0061] Table 2. Indoor Demulsification Performance Evaluation Experiment

[0062]

[0063] Experiments have shown that the microemulsion demulsifier prepared using the method of this invention has a significantly higher demulsification effect on heavy oil emulsions at the Gudao Joint Station than the demulsifier used in Comparative Example 2 (i.e., the field-use demulsifier). Among them, the demulsifier in Example 2 showed the best effect; at a dosage concentration of 150 mg / L, the demulsifier in Example 2 was superior to that in Comparative Example 2 at a dosage concentration of 200 mg / L. Even at a dosage of 150 mg / L, the crude oil dehydration rate could still reach over 90%, enabling demulsification of the Gudao heavy oil produced fluid at a relatively low dosage concentration.

[0064] The present invention has been described in detail above with reference to specific embodiments and exemplary examples; however, these descriptions should not be construed as limiting the present invention. Those skilled in the art will understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and embodiments of the present invention without departing from the spirit and scope of the invention, and all such modifications and improvements fall within the scope of the present invention. The scope of protection of the present invention is defined by the appended claims.

Claims

1. A microemulsion demulsifier, comprising a polyether-type demulsifier and an acrylate copolymer, wherein the microemulsion demulsifier is obtained by microemulsion polymerization of raw materials including a hydrophobic monomer, a hydrophilic monomer, a polyether-type demulsifier, a co-emulsifier, an initiator, and optionally a crosslinking monomer, wherein the weight ratio of the hydrophilic monomer to the hydrophobic monomer is (5:95) to (50:50); and the amount of the polyether-type demulsifier is 0.25 to 5 times the total amount of the hydrophilic monomer and the hydrophobic monomer by weight.

2. The microemulsion demulsifier according to claim 1, characterized in that: The polyether-type demulsifier is a water-soluble polyether demulsifier.

3. The microemulsion demulsifier according to claim 2, characterized in that: The polyether-type demulsifier is a block polyether with alcohols as initiators.

4. The microemulsion demulsifier according to claim 1, characterized in that: The acrylate copolymer is a copolymer polymerized from hydrophobic monomers, hydrophilic monomers, and optionally crosslinking monomers.

5. The microemulsion demulsifier according to claim 4, characterized in that: The hydrophobic monomer is selected from at least one of styrene, methacrylate compounds, and acrylate compounds; The hydrophilic monomer is selected from at least one of acrylic compounds and polyethers with double bonds at the end groups; The crosslinking monomer is selected from alkenes containing two or more unsaturated double bonds.

6. The microemulsion demulsifier according to claim 5, characterized in that: The hydrophobic monomer is selected from at least one of methyl methacrylate, methyl acrylate, ethyl acrylate, butyl acrylate, butyl methacrylate, ethylhexyl acrylate, isooctyl methacrylate, lauryl acrylate, lauryl methacrylate, octadecyl acrylate, and octadecyl methacrylate. The hydrophilic monomer is selected from at least one of acrylic acid compounds and polyoxyethylene ethers with double bonds at the end groups; The crosslinking monomer is selected from at least one of diethylene glycol dimethacrylate, trimethylolpropionic acid triacrylate, butanediol dimethacrylate, divinylbenzene, butanediol diacrylate, and N,N'-methylenebisacrylamide.

7. The microemulsion demulsifier according to claim 6, characterized in that: The hydrophilic monomer is selected from at least one of acrylic acid, allyl polyoxyethylene ether, and polyethylene glycol monomethyl ether acrylate.

8. The microemulsion demulsifier according to claim 1, characterized in that: The particle size of the microemulsion demulsifier is 10~100nm.

9. The microemulsion demulsifier according to claim 8, characterized in that: The particle size of the microemulsion demulsifier is 30~80nm.

10. A method for preparing a microemulsion demulsifier according to any one of claims 1 to 9, comprising microemulsion polymerization of raw materials including hydrophobic monomers, hydrophilic monomers, polyether-type demulsifiers, co-emulsifiers, initiators, and optionally crosslinking monomers.

11. The preparation method according to claim 10, characterized in that: The weight ratio of the hydrophilic monomer to the hydrophobic monomer is (5:95) to (50:50). The amount of the crosslinking monomer is 0 to 3 wt% of the total amount of the hydrophilic monomer and the hydrophobic monomer.

12. The preparation method according to claim 11, characterized in that: The weight ratio of the hydrophilic monomer to the hydrophobic monomer is (5:95) to (40:60). The amount of the crosslinking monomer is 0.001 to 0.3 wt% of the total amount of the hydrophilic monomer and the hydrophobic monomer.

13. The preparation method according to claim 10, characterized in that: The co-emulsifier is an organic alcohol; The initiator is selected from redox initiators and / or azo initiators.

14. The preparation method according to claim 13, characterized in that: The co-emulsifier is selected from at least one of methanol, ethanol, isopropanol, tert-butanol, n-octanol, and dodecanol; The redox initiator is selected from at least one of ammonium persulfate-sodium bisulfite and potassium persulfate-sodium bisulfite; the azo initiator is selected from at least one of dimethyl 2,2-azobisisobutyrate, 2,2-azo[2-(2-imidazolinyl)propane]dihydrochloride, azobisisobutyramidine hydrochloride, and azobisisobutyramidine hydrochloride.

15. The preparation method according to claim 10, characterized in that: The amount of the polyether-type demulsifier used, by weight, is 0.25 to 5 times the total amount of the hydrophilic monomer and the hydrophobic monomer. The amount of the co-emulsifier, by weight, is 0.25 to 5 times the total amount of the hydrophilic monomer and the hydrophobic monomer; The amount of the initiator is 0.1 to 2 wt% of the total amount of the hydrophilic monomer and the hydrophobic monomer.

16. The preparation method according to claim 15, characterized in that: The amount of the polyether-type demulsifier by weight is 0.5 to 3 times the total amount of the hydrophilic monomer and the hydrophobic monomer; The amount of the co-emulsifier, by weight, is 0.5 to 3 times the total amount of the hydrophilic monomer and the hydrophobic monomer; The amount of the initiator is 0.3 to 1.5 wt% of the total amount of the hydrophilic monomer and the hydrophobic monomer.

17. The method of any one of claims 10 to 16, wherein Includes the following steps: The co-emulsifier and polyether-type demulsifier are mixed evenly, and water, hydrophobic monomers, and optional crosslinking monomers are added. Under a nitrogen atmosphere, a portion of the initiator is added, followed by the addition of hydrophilic monomers and the remaining initiator. The mixture is then cooled to room temperature to obtain the microemulsion demulsifier. Optionally, some hydrophilic monomers may be added together with hydrophobic monomers.

18. The preparation method according to claim 17, characterized in that: Add water, hydrophobic monomers, and optional crosslinking monomers, heat to 30~80℃, add part of the initiator under a nitrogen atmosphere, react for 3~5 hours, then add hydrophilic monomers and the remaining initiator, and keep the reaction at the temperature for 2~5 hours.

19. The application of the microemulsion demulsifier according to any one of claims 1 to 9 or the microemulsion demulsifier obtained by the preparation method according to any one of claims 10 to 18 in crude oil demulsification.

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