A comb-shaped polyether reverse demulsifier and its preparation method

Abstract

This invention discloses a comb-shaped polyether reverse demulsifier and its preparation method, relating to the field of oilfield chemical technology. The preparation method includes the following steps: dissolving N-(3-dimethylaminopropyl)methacrylamide and styrene in ethanol to obtain a monomer solution; purging with nitrogen for 15 min to remove oxygen; adding an initiator; and polymerizing to obtain a copolymer solution of N-(3-dimethylaminopropyl)methacrylamide-styrene. Adding an equimolar amount of p-chlorobenzaldehyde (as in step S1) and a certain amount of aluminum tribromide to the copolymer solution; stirring for a certain time to obtain a modified copolymer solution; and adding an equimolar amount of polyether monoamine (as in step S2) to the modified copolymer solution; and stirring at room temperature for 10–14 h to obtain the final product. This invention has the advantages of low dosage, fast oil removal speed, and high efficiency. The prepared reverse demulsifier has a good treatment effect on oilfield produced fluids, with an oil removal rate greater than 90%, and exhibits excellent oil removal performance for heavy oilfield produced fluids.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically to a comb-shaped polyether reverse demulsifier and its preparation method. Background Technology

[0002] As offshore oilfields enter the mid-to-late stages of water injection production, the water content in the produced fluid increases significantly, posing a substantial challenge to normal production. Due to limited space on offshore platforms, expanding or increasing the capacity of produced fluid treatment equipment is extremely difficult. This leads to a significant reduction in the residence time of produced fluid in existing treatment equipment, thus placing higher demands on the performance of treatment agents. The process flow for producing fluid treatment on offshore platforms involves the produced fluid entering a three-phase separator, undergoing synergistic treatment with demulsifiers and reverse demulsifiers, and then the desorbed water entering the water system for further treatment with a cleaning agent. The better the reverse demulsifier's effect, the lower the treatment pressure in the water system. Currently, cationic polymer reverse demulsifiers and block polyethers are commonly used reverse demulsifiers. Cationic polymer reverse demulsifiers effectively neutralize the negative charge on the oil droplet surface, promoting droplet aggregation and coalescence, but they can produce sticky sludge. Block polyethers reduce the strength of the oil-water interface film, promoting droplet coalescence without producing sludge, but their oil removal rate and speed are relatively slow. Summary of the Invention

[0003] In view of this, the present invention proposes a comb-shaped polyether reverse demulsifier and its preparation method, which can achieve efficient oil removal without producing sludge.

[0004] This invention discloses a comb-shaped polyether reverse demulsifier and its preparation method, comprising the following steps:

[0005] Step S1: Dissolve N-(3-dimethylaminopropyl)methacrylamide and styrene in ethanol to obtain a monomer solution. After purging with nitrogen for 15 min to remove oxygen, add an initiator and polymerize to obtain a copolymer solution of N-(3-dimethylaminopropyl)methacrylamide-styrene.

[0006] Step S2: Add p-chlorobenzaldehyde, which is equimolar in amount of styrene as in step S1, and a certain amount of aluminum tribromide to the copolymer solution, and stir the reaction for a certain time to obtain the modified copolymer solution.

[0007] Step S3: Add polyether monoamine in the same molar amount as p-chlorobenzaldehyde in step S2 to the modified copolymer solution, and stir at room temperature for 10-14 hours to obtain the product.

[0008] In one embodiment of the present invention, the mass concentration of the monomer solution in step S1 is 15-21%.

[0009] In one embodiment of the present invention, the ratio of styrene to N-(3-dimethylaminopropyl)methacrylamide in step S1 is 1:5 to 8, based on a molar ratio.

[0010] In one embodiment of the present invention, the initiator in step S1 is azobisisobutyronitrile, and the amount added is 0.1 to 0.3% of the monomer mass.

[0011] One embodiment of the present invention is that the polymerization reaction conditions in step S1 are: reaction at 50-65°C for 10-14 hours.

[0012] In one embodiment of the present invention, the ratio of aluminum tribromide to p-chlorobenzaldehyde in step S2 is 1:4 to 8, based on a molar ratio.

[0013] One embodiment of the present invention is that the stirring reaction conditions in step S2 are: reaction at 25-40°C for 5-12 hours.

[0014] In one embodiment of the present invention, the polyether monoamine in step S3 is one of M-1000, M-2005, M-2070, and M3085.

[0015] And the comb-shaped polyether reverse demulsifier prepared by the above method.

[0016] The technical advantages of this invention are as follows:

[0017] This invention has the advantages of low dosage, fast oil removal speed, and high efficiency. The prepared reverse demulsifier has a good treatment effect on oilfield produced fluids, with an oil removal rate of more than 90%, and has good oil removal performance for heavy oil field produced fluids. Attached Figure Description

[0018] Figure 1 This is a graph showing the evaluation results of the reverse demulsification experiment in this invention. Detailed Implementation

[0019] The present invention will be further described in detail below with reference to the embodiments. However, the implementation of the present invention is not limited thereto. Unless otherwise specified, the experimental methods used in the following embodiments are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0020] Example 1

[0021] (1) 30.05 g (0.2 mol) N-(3-dimethylaminopropyl)methacrylamide, 3.47 g (0.033 mol) styrene and 134.08 g ethanol were added to a 500 mL screw-top bottle, and after magnetic stirring to dissolve, nitrogen was purged for 15 min to remove oxygen. Then 0.05 g azobisisobutyronitrile was added, the bottle was sealed tightly, and the reaction solution was magnetically stirred at 55 °C for 10 h to obtain N-(3-dimethylaminopropyl)methacrylamide-styrene copolymer.

[0022] (2) Add 4.64 g (0.033 mol) p-chlorobenzaldehyde and 1.47 g (0.0055 mol) aluminum tribromide to the copolymer solution, purge with nitrogen for 5 min, and react at 30 °C for 12 h to obtain a modified copolymer with benzaldehyde as a partial side group.

[0023] (3) Add 66g (0.033mol) of polyether monoamine M-2005 to the modified copolymer solution and stir at room temperature for 12h to obtain comb-shaped polyether reverse demulsifier.

[0024] Example 2

[0025] The implementation method of this embodiment is basically the same as that of Example 1. The difference is that in step (1), the amount of N-(3-dimethylaminopropyl)methacrylamide added is 29.79g (0.175mol), the amount of styrene added is 3.64g (0.035mol), in step (2) the amount of p-chlorobenzaldehyde added is 4.92g (0.035mol), the amount of aluminum tribromide added is 1.55g (0.0058mol), and in step (3) the amount of M-2005 added is 70g (0.035mol).

[0026] Example 3

[0027] The implementation method of this embodiment is basically the same as that of Example 1. The difference is that in step (1), the amount of N-(3-dimethylaminopropyl)methacrylamide added is 30.98g (0.182mol), the amount of styrene added is 2.71g (0.026mol), in step (2) the amount of p-chlorobenzaldehyde added is 3.65g (0.026mol), the amount of aluminum tribromide added is 1.15g (0.0043mol), and in step (3) the amount of M-2005 added is 52g (0.026mol).

[0028] Example 4

[0029] The implementation method of this embodiment is basically the same as that of Example 1. The difference is that in step (1), the amount of N-(3-dimethylaminopropyl)methacrylamide added is 31.33g (0.184mol), the amount of styrene added is 2.39g (0.023mol), in step (2) the amount of p-chlorobenzaldehyde added is 3.23g (0.023mol), the amount of aluminum tribromide added is 1.01g (0.0038mol), and in step (3) the amount of M-2005 added is 46g (0.023mol).

[0030] Example 5

[0031] The implementation method of this embodiment is basically the same as that of Example 1, except that in step (1), the amount of N-(3-dimethylaminopropyl)methacrylamide added is 30.64g (0.180mol), the amount of styrene added is 2.08g (0.020mol), the amount of p-chlorobenzaldehyde added in S2 is 2.81g (0.020mol), the amount of aluminum tribromide added is 0.88g (0.0033mol), and the amount of M-2005 added in S3 is 40g (0.020mol).

[0032] Example 6

[0033] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of ethanol added in step (1) is 189.94g.

[0034] Example 7

[0035] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of azobisisobutyronitrile added in step (1) is 0.0337g.

[0036] Example 8

[0037] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of azobisisobutyronitrile added in step (1) is 0.067g.

[0038] Example 9

[0039] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of azobisisobutyronitrile added in step (1) is 0.1g.

[0040] Example 10

[0041] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 50°C.

[0042] Example 11

[0043] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 60°C.

[0044] Example 12

[0045] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 65°C.

[0046] Example 13

[0047] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of aluminum tribromide added in step (2) is 2.2g (0.00825mol).

[0048] Example 14

[0049] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of aluminum tribromide added in step (2) is 1.76g (0.0066mol).

[0050] Example 15

[0051] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of aluminum tribromide added in step (2) is 1.25g (0.0047mol).

[0052] Example 16

[0053] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of aluminum tribromide added in step (2) is 1.1g (0.004125mol).

[0054] Example 17

[0055] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (2) is 25°C.

[0056] Example 18

[0057] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (2) is 35°C.

[0058] Example 19

[0059] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (2) is 40°C.

[0060] Example 20

[0061] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction time in step (2) is 8 hours.

[0062] Example 21

[0063] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction time in step (2) is 12h.

[0064] Example 22

[0065] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction time in step (2) is 16h.

[0066] Example 23

[0067] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the polyether monoamine in step (3) is M-1000.

[0068] Example 24

[0069] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the polyether monoamine in step (3) is M-2070.

[0070] Example 25

[0071] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the polyether monoamine in step (3) is M-3085.

[0072] Comparative Example 1

[0073] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of ethanol added in step (1) is 301.68g.

[0074] Comparative Example 2

[0075] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the amount of ethanol added in step (1) is 100.56g.

[0076] Comparative Example 3

[0077] The implementation method of this embodiment is basically the same as that of Example 1, except that the amount of azobisisobutyronitrile added in step (1) is 0.1g.

[0078] Comparative Example 4

[0079] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction temperature in step (1) is 70°C.

[0080] Comparative Example 5

[0081] The implementation method of this embodiment is basically the same as that of embodiment 1, except that the reaction time in step (2) is 4 hours.

[0082] To better illustrate the technical effects of the present invention, the following provides corresponding characterization and performance evaluation of the relevant embodiments.

[0083] Performance Evaluation

[0084] (1) Effect of the molar ratio of N-(3-dimethylaminopropyl)methacryloyl to styrene on the performance of comb-shaped polyether reverse demulsifier

[0085] The performance evaluation method for reverse demulsifiers is as follows: Take 140 mL of produced fluid (taken from a heavy oil field in the Bohai Sea, with a comprehensive water cut of 95.6%, an oil content in the aqueous phase of 4800 mg / L, and a crude oil density of 0.9650 g / cm³). 3 The mixture was kept in a 70°C water bath for 10 minutes, then 25 mg / L of reverse demulsifier was added. After shaking by hand 50 times, it was kept in a 70°C water bath for 5 minutes. Finally, 10 mL of the lower supernatant was collected, and the oil removal rate was calculated by measuring the turbidity before and after reverse demulsification. Examples 1-5 were evaluated according to the described method, and the results are shown in Table 1.

[0086] Table 1. Effect of the molar ratio of N-(3-dimethylaminopropyl)methacrylamide to styrene on the performance of comb-shaped polyether reverse demulsifiers.

[0087]

[0088] Table 1 shows the effect of the molar ratio of N-(3-dimethylaminopropyl)methacrylamide to styrene on the performance of comb-shaped polyether reverse demulsifiers. Physical images of the evaluation process are shown below. Figure 1 As shown in Table 1, with the decrease of styrene in the copolymer, the content of polyether in the final product decreases, and the reverse demulsification performance of the product decreases. When the molar ratio of N-(3-dimethylaminopropyl)methacryloyl to styrene is in the range of 5:1 to 8:1, the oil removal rate of reverse demulsification can reach more than 90%.

[0089] (2) Effect of monomer concentration on the performance of comb-shaped polyether reverse demulsifier

[0090] Demulsification performance evaluation experiments were conducted on Examples 1 and 6, as well as Comparative Examples 1 and 2, and the results are shown in Table 2:

[0091] Table 2. Effect of monomer concentration on the performance of comb-shaped polyether reverse demulsifiers.

[0092]

[0093] Table 2 shows the effect of monomer concentration on the performance of comb-shaped polyether reverse demulsifier in step (1). As can be seen from Table 2, as the monomer concentration in S1 increases, the oil removal rate of the final reaction product increases. This is because the molecular weight of the copolymer increases with the increase of monomer concentration, which is beneficial for capturing more oil droplets to achieve aggregation and coagulation. However, when the monomer concentration is 25%, the flowability of the final product is very poor and it is not practical.

[0094] (3) Effect of initiator concentration on the performance of comb-shaped polyether reverse demulsifier

[0095] Demulsification performance evaluation experiments were conducted on Examples 1, 7-9, and Comparative Example 3, and the results are shown in Table 3:

[0096] Table 3. Effect of monomer concentration on the performance of comb-shaped polyether reverse demulsifiers

[0097] Group Example 1 Example 7 Example 8 Example 9 Comparative Example 3 Initiator concentration (%) 0.15 0.1 0.2 0.3 0.4 Oil removal rate (%) 92.1 93.0 90.8 90.0 85.4

[0098] Table 3 shows the effect of initiator concentration on the performance of comb-shaped polyether reverse demulsifier in step (1). As shown in Table 3, when the initiator dosage is in the range of 0.1% to 0.3%, the final product exhibits good reverse demulsification performance, with an oil removal rate greater than 90%. However, when the initiator dosage is 0.4%, the oil removal rate of the product decreases significantly. This may be because when the initiator dosage is too high, the molecular weight of the product decreases, leading to a decline in the ability to aggregate and coalesce multiple oil droplets, thus resulting in a decrease in the oil removal rate.

[0099] (4) Effect of reaction temperature in step (1) on the performance of comb-shaped polyether reverse demulsifier

[0100] Demulsification performance evaluation experiments were conducted on Examples 1, 10-12, and Comparative Example 4, and the results are shown in Table 4:

[0101] Table 4. Results of the effect of reaction temperature in step (1) on the performance of comb-shaped polyether reverse demulsifier

[0102] Group Example 1 Example 10 Example 11 Example 12 Comparative Example 4 Reaction temperature (°C) 55 50 60 65 70 Oil removal rate (%) 92.1 92.4 91.2 90.2 87.4

[0103] Table 4 shows the effect of reaction temperature on the performance of comb-shaped polyether reverse demulsifier in step (1). As can be seen from Table 4, when the reaction temperature is in the range of 50℃ to 65℃, the final product has good reverse demulsification performance. However, when the reaction temperature is 70℃, the oil removal rate of the product is less than 90%. This may be because when the temperature is too high, the molecular weight of the product decreases, resulting in the aggregation and polymerization of multiple oil droplets and a decrease in performance, thus leading to a decrease in the oil removal rate.

[0104] (5) Effect of aluminum tribromide catalyst dosage on the performance of comb-shaped polyether reverse demulsifier

[0105] Demulsification performance evaluation experiments were conducted on Examples 1 and 13-16, and the results are shown in Table 5:

[0106] Table 5. Effect of aluminum tribromide catalyst dosage on the performance of comb-shaped polyether reverse demulsifier.

[0107]

[0108] Table 5 shows the effect of the amount of aluminum tribromide added as a catalyst in step (2) on the performance of the comb-shaped polyether reverse demulsifier. As shown in Table 5, the oil removal rate of the final product decreases with decreasing aluminum tribromide dosage. However, when the molar ratio of p-chlorobenzaldehyde to aluminum tribromide is in the range of 4:1 to 8:1, the oil removal rate is greater than 90%. This is because the Friedel-Crafts reaction between p-chlorobenzaldehyde and styrene requires a sufficient amount of catalyst to improve the reaction conversion rate. When the amount of catalyst is too small, the amount of polyether that can be attached to the final reaction product decreases, and the reverse demulsification performance of the product will decline.

[0109] (6) Effect of reaction temperature in step (2) on the performance of comb-shaped polyether reverse demulsifier

[0110] Demulsification performance evaluation experiments were conducted on Examples 1 and 17-19, and the results are shown in Table 6:

[0111] Table 6. Results of the effect of reaction temperature in step (2) on the performance of comb-shaped polyether reverse demulsifier

[0112] Example 1 17 18 19 Reaction temperature (°C) 30 25 35 40 Oil removal rate (%) 92.1 90.5 92.5 92.5

[0113] Table 6 shows the effect of reaction temperature in step (2) on the performance of the comb-shaped polyether reverse demulsifier. Since chlorostyrene, in addition to undergoing a Friedel-Crafts reaction with styrene, also undergoes a quaternization reaction with N-(3-dimethylaminopropyl)methacrylamide at high temperatures, the reaction temperature in step (2) should be controlled below 40°C to avoid the quaternization reaction. The results in Table 6 show that when the reaction temperature is in the range of 25°C to 40°C, the final product exhibits good performance, with an oil removal rate greater than 90%.

[0114] (7) Effect of reaction time in step (2) on the performance of comb-shaped polyether reverse demulsifier

[0115] Demulsification performance evaluation experiments were conducted on Examples 1, 20-22, and Comparative Example 5, and the results are shown in Table 7:

[0116] Table 7 Results of the effect of reaction time in step (2) on the performance of comb-shaped polyether reverse demulsifier

[0117] Group Example 1 Example 20 Example 21 Example 22 Comparative Example 5 Reaction time (h) 20 8 12 16 4 Oil removal rate (%) 92.1 80.4 92.1 92.1 53.3

[0118] Table 7 shows the effect of reaction time in step (2) on the performance of the comb-shaped polyether reverse demulsifier. As can be seen from Table 7, when the reaction time in step (2) is ≥12h, the oil removal rate of the final product is constant at 92.1%, indicating that the reaction in step (2) has basically ended.

[0119] (8) The effect of polyether monoamine type on the performance of comb-shaped polyether reverse demulsifier

[0120] Demulsification performance evaluation experiments were conducted on Examples 1 and 23-25, and the results are shown in Table 8:

[0121] Table 8. Effects of Polyether Monoamine Type on the Performance of Comb-Shaped Polyether Reverse Demulsifiers

[0122] Example 1 23 24 25 Polyether monoamine M-2005 M-1000 M-2070 M-3085 Oil removal rate (%) 92.1 90.7 93.8 93.2

[0123] Table 8 shows the effect of the type of polyether monoamine in step (3) on the performance of the comb-shaped polyether reverse demulsifier. As can be seen from Table 8, when the polyether monoamine is M-1000, M-2005, M-2070 and M-3085, the oil removal rate of the final product is greater than 90%, which proves that the reverse demulsifier prepared by the present invention has good performance.

[0124] In summary, this invention has prepared a highly efficient reverse demulsifier that can effectively remove oil from heavy oil produced fluid without producing sludge, with an oil removal rate of more than 90%.

[0125] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the embodiments of the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be defined by the scope of the claims.

Claims

1. A process for the preparation of a comb polyether reverse emulsion breaker characterized in that, The method comprises the following steps: Step S1: dissolving N-(3-dimethylaminopropyl) methacrylamide and styrene in ethanol to obtain a monomer solution, adding an initiator after deoxidizing for 15 min under nitrogen, and polymerizing to obtain a copolymer solution of N-(3-dimethylaminopropyl) methacrylamide-styrene, wherein the mass concentration of the monomer solution is 15-21%; The ratio of styrene and N-(3-dimethylaminopropyl) methacrylamide is 1:5-8 in terms of molar ratio; The initiator is azobisisobutyronitrile, and the addition amount is 0.1-0.3% of the mass of the monomers; The polymerization reaction condition is 10-14 h of reaction at 50-65 ℃; Step S2: adding p-chlorobenzaldehyde in an amount equal to that of styrene in step S1 and a certain amount of aluminum tribromide into the copolymer solution, and stirring for a certain time to obtain a modified copolymer solution, wherein the ratio of aluminum tribromide and p-chlorobenzaldehyde is 1:4-8 in terms of molar ratio; The stirring reaction condition is 5-12 h of reaction at 25-40 ℃; The polyether monoamine is one of M-1000, M-2005, M-2070 and M3085; Step S3: adding polyether monoamine in an amount equal to that of p-chlorobenzaldehyde in step S2 into the modified copolymer solution, and stirring for 10-14 h at room temperature to obtain the product.

2. A comb polyether reverse emulsion breaker characterized in that, The product is prepared by the method of claim 1.

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