A high molecular emulsion breaker, its preparation method and application

Abstract

The application discloses a high-molecular demulsifier and a preparation method and application thereof, and belongs to the technical field of oil exploitation. The high-molecular demulsifier has a structure as shown in the formula (I): formula (I); wherein R is selected from any one of NH2-(CH2CH2NH)m-CH2CH2, m represents an integer of 1-4, n represents an integer of 25-600, a represents an integer of 60-200, and b represents an integer of 40-150. The high-molecular demulsifier has good demulsification effect, improves the water phase cleanliness of demulsification and water discharge, is suitable for various working conditions, and solves the problem of difficult treatment of existing oilfield three-phase oil.

Description

TECHNICAL FIELD

[0001] The application relates to a high-molecular demulsifier as well as a preparation method and application thereof, and belongs to the technical field of oil exploitation. BACKGROUND

[0002] With the development of oil fields into the middle and later stages, a large amount of surfactants and polymers are used in the secondary oil recovery and tertiary oil recovery process, resulting in an increase in the emulsified oil content in the produced liquid and an increase in the difficulty of oil-water separation. Traditional demulsifiers, such as inorganic salts, low-molecular surfactants and the like, have problems such as a large dosage, poor effect, easy secondary pollution and the like, and therefore cannot effectively treat the complex emulsions.

[0003] A Chinese patent CN103709390B discloses a block polyether demulsifier taking polyethylene imine as a starting agent and a preparation method thereof, and the demulsifier has good demulsification effect on W / O type emulsions generated after oil field polymer flooding. However, the demulsifier product has a relatively low molecular weight and does not have good universality; and the demulsifier is a non-ionic demulsifier, and in actual application, a cationic polymer water purifier needs to be additionally added to improve water quality, thereby increasing the treatment cost. SUMMARY

[0004] The application aims to provide a high-molecular demulsifier as well as a preparation method and application thereof, which has good demulsification effect, improves the water phase cleanliness of demulsification and drainage water, is suitable for various working conditions, and solves the problem of difficult treatment of existing oil field three-recovery crude oil.

[0005] To achieve the above object, the technical scheme adopted by the application is as follows:

[0006] According to one aspect of the application, a high-molecular demulsifier is provided, which has a structure as shown in formula (I):

[0007] Formula (I);

[0008] wherein R is selected from any one of NH2-(CH2CH2NH)m-CH2CH2, and m represents an integer of 1-4;

[0009] n represents an integer of 25-600;

[0010] a represents an integer of 60-200;

[0011] b represents an integer of 40-150.

[0012] Optionally, the molecular weight of the high-molecular demulsifier is 10000-35000.

[0013] According to another aspect of the application, a method for preparing the high-molecular demulsifier described in any one of the above aspects is provided, which comprises:

[0014] (1) polyethylene imine and basic catalyst are added into a reaction kettle, and stirring is performed under heating, and vacuum and nitrogen replacement are performed to ensure that the reaction kettle is free of moisture and oxygen, and then propylene oxide is introduced at 130-140°C, and after the reaction is completed, the temperature is lowered to 120-130°C, and then ethylene oxide is introduced, to obtain a polyether;

[0015] (2) polyethylene polyamine and a solvent are added into a flask, and then epichlorohydrin is added dropwise, and the temperature is controlled to be <30°C during the dropwise addition, and after the dropwise addition is completed, the reaction is performed at 20-30°C for 14-18h, to obtain a modifier;

[0016] (3) the polyether is added into a flask, and the temperature is raised to 85-95°C, and then the modifier is added dropwise, and after the dropwise addition is completed, the reaction is performed for 2-3h, to obtain a crude high-molecular demulsifier;

[0017] (4) n-hexane is added into the crude high-molecular demulsifier, and extraction is performed, and two phases are separated, and the lower target product is collected, and the target product is subjected to elevated temperature distillation at 140-160°C under reduced pressure to remove the solvent, to obtain the high-molecular demulsifier.

[0018] Optionally, in step (1), the mass ratio of the polyethylene imine, propylene oxide and ethylene oxide is 1:(0.8-10):(0.4-8).

[0019] The basic catalyst accounts for 0.3-1wt% of the total mass of the propylene oxide and the ethylene oxide.

[0020] Optionally, in step (1), the basic catalyst is selected from any one of potassium hydroxide, sodium hydroxide and potassium methoxide.

[0021] Optionally, in step (1), the molecular weight of the polyethylene imine is 1000-25000.

[0022] Optionally, in step (2), the molar ratio of the polyethylene polyamine to the epichlorohydrin is 1:(1-2).

[0023] Optionally, in step (2), the polyethylene polyamine is selected from any one of diethylene triamine, triethylene tetramine, tetraethylene pentamine and pentaethylene hexamine.

[0024] The solvent is selected from any one of ethanol, ethylene glycol and ethylene glycol monobutyl ether.

[0025] Optionally, in step (3), the mass ratio of the modifier to the polyether is 1:(10-50).

[0026] According to still another aspect of the present application, the use of the high-molecular demulsifier described in any one of the above in the process of demulsification and dehydration of produced liquid crude oil is provided, and the amount of the high-molecular demulsifier is 90-110ppm.

[0027] The beneficial effects of the present application include but are not limited to:

[0028] 1. The high molecular demulsifier of the present application has a high molecular weight, and its long chain structure can bridge oil droplets and water droplets to form larger aggregates, and then coalesce, separate and demulsify, effectively removing water in crude oil, reducing the water content of crude oil, and ensuring the water content standard of crude oil export; and also has a certain cationic degree, which can not only form an ion pair with the emulsifier molecules in the anionic emulsifier to destroy the coating layer of the emulsifier, making the emulsion lose stability and then demulsify, but also can neutralize the negative charge on the surface of solid suspensions, to a certain extent, improve the water phase cleanliness.

[0029] 2. The high molecular demulsifier of the present application, the starting agent selects branched polyethyleneimine, which has a certain degree of branching and molecular degree, and then ring-opening polymerization with propylene oxide and ethylene oxide to form a long polyether segment with higher branching degree, which can significantly reduce the interfacial tension; wherein, by optimizing the ratio of propylene oxide and ethylene oxide, the contact points of the demulsifier molecules in the water phase and the oil phase can be adjusted, and the area occupied by the molecules on the oil-water interface can be increased, thereby effectively improving the demulsification performance.

[0030] 3. The high molecular demulsifier of the present application, which uses epichlorohydrin and polyethylene polyamine to react to form a long chain segment modifier, which on the one hand increases the molecular weight of the polyether after modification, and on the other hand, through modification experiments, a quaternary amination reaction occurs, forming a demulsifier with stronger cationicity, which has a water purification effect and can improve the water phase cleanliness of demulsified water.

[0031] 4. The preparation method of the high molecular demulsifier of the present application is simple, the raw materials are easy to obtain, and easy to industrialize production; the high molecular demulsifier prepared has the advantages of less dosage, high demulsification rate, clear water quality, and fast dehydration speed, and is widely used in oilfield produced liquid treatment, effectively removing emulsified water in crude oil, improving the quality of crude oil; it is beneficial to reduce equipment corrosion in subsequent refining process, reduce operation difficulty, reduce the amount of chemical agents in sewage treatment process, shorten the treatment time, and thus reduce the treatment cost. BRIEF DESCRIPTION OF DRAWINGS

[0032] The drawings described herein are used to provide further understanding of the present application, and constitute a part of the present application. The schematic embodiments of the present application and their descriptions are used to explain the present application, and do not constitute an improper limitation on the present application. In the drawings:

[0033] Figure 1 It is the infrared spectrum of the high molecular demulsifier 3# of the present application embodiment 3.

[0034] Figure 2 It is the GPC graph of the high molecular demulsifier 3# of the present application embodiment 3. DETAILED DESCRIPTION

[0035] The endpoints of the ranges and any values disclosed herein are not limited to the precise values recited as the exact dimensions are not considered critical for the purposes of the application. Any numerical range recited herein is intended to include all sub-ranges of the same numbers (i.e., every subset of numbers within the indicated range). For instances of numerical ranges, the endpoints are included within the range.

[0036] Unless otherwise indicated, conventional methods or those modifications suggested by the manufacturer were used. Unless otherwise indicated, the materials used and, where appropriate, the equipment, were those available from commercial suppliers such as Sigma-Aldrich.

[0037] Example 1

[0038] A method for preparing a high molecular emulsion breaker, comprising:

[0039] (1) 50 g of polyethyleneimine (PEI-3000) and 1.5 g of potassium hydroxide were added to a polymerization reactor, and the temperature was raised while stirring, and vacuum and nitrogen replacement were performed to ensure that there was no moisture or oxygen in the reactor. At 135°C, 120 g of propylene oxide was slowly introduced, and after the reaction was complete, the temperature was lowered to 125°C, and 100 g of ethylene oxide was slowly introduced. After the reaction was complete, a polyether was formed. The reaction equation is as follows (where n is 70, a is 124, and b is 136):

[0040]

[0041] (2) 103 g of diethylenetriamine and 145 g of ethylene glycol were added to a three-necked flask, and 184 g of epichlorohydrin was slowly added dropwise while controlling the temperature to be <30°C. After the addition was complete, the reaction was allowed to proceed at 25°C for 16 h to obtain a modifier. The reaction equation is as follows:

[0042]

[0043] (3) 200 g of the polyether synthesized in step (1) was added to a three-necked flask, and the temperature was raised to 90°C. Then, 10 g of the modifier synthesized in step (2) was slowly added dropwise, and after the addition was complete, the reaction was allowed to proceed at 90°C for 2.5 h to obtain a crude high molecular emulsion breaker. The reaction equation is as follows:

[0044]

[0045] (4) n-hexane was added to the crude high molecular emulsion breaker, and extraction was performed to separate the two phases. The lower layer of the target product was collected, and the target product was subjected to distillation at 150°C under reduced pressure to remove the solvent, thereby obtaining a high molecular emulsion breaker 1#, which had a molecular weight of 23877.

[0046] Example 2

[0047] A method for preparing a high molecular emulsion breaker, comprising:

[0048] (1) Put 80 g of polyethyleneimine (PEI-5000) and 1.4 g of potassium hydroxide into a polymerization reactor, start stirring and heating, and perform vacuum and nitrogen replacement to ensure that the reactor is free of moisture and oxygen, slowly pass in 120 g of propylene oxide at 135°C, and after the reaction of propylene oxide is complete, cool to 125°C, slowly pass in 70 g of ethylene oxide, and after the reaction is complete, form a polyether, the reaction equation being the same as that of step (1) of Example 1 (wherein n is 116, a is 129, and b is 99);

[0049] (2) Put 146 g of triethylenetetramine and 185 g of ethylene glycol into a three-necked flask, slowly drop in 184 g of epichlorohydrin, control the temperature to be <30°C during the dropping process, after the dropping is complete, incubate at 25°C for 16 h to obtain a modifier; the reaction equation is as follows:

[0050]

[0051] (3) Put 200 g of the polyether synthesized in step (1) into a three-necked flask, heat to 90°C, slowly drop in 10 g of the modifier synthesized in step (2), after the dropping is complete, incubate at 90°C for 2.5 h to obtain a crude high molecular emulsion breaker; the reaction equation is as follows:

[0052]

[0053] (4) Add n-hexane to the crude high molecular emulsion breaker to perform extraction, separate the two phases, collect the lower target product, and heat the target product to 150°C to perform reduced-pressure distillation to remove the solvent, and thus obtain a high molecular emulsion breaker 2#, the molecular weight of which is 25172.

[0054] Example 3

[0055] A method for preparing a high molecular emulsion breaker, comprising:

[0056] (1) Put 200 g of polyethyleneimine (PEI-8000) and 1.8 g of potassium hydroxide into a polymerization reactor, start stirring and heating, and perform vacuum and nitrogen replacement to ensure that the reactor is free of moisture and oxygen, slowly pass in 160 g of propylene oxide at 135°C, and after the reaction of propylene oxide is complete, cool to 125°C, slowly pass in 100 g of ethylene oxide, and after the reaction is complete, form a polyether, the reaction equation being the same as that of step (1) of Example 1 (wherein n is 186, a is 110, and b is 91);

[0057] (2) Put 189 g tetraethylene pentamine and 210 g ethylene glycol into a three-necked flask, slowly drop 115 g epoxy chloropropane, control the temperature <30°C during the dropping process, after the dropping process, keep the temperature at 25°C for 16 h to obtain the modifier; the reaction equation is as follows:

[0058]

[0059] (3) Put 220 g polyether synthesized in step (1) into a three-necked flask, slowly drop 10 g modifier synthesized in step (2) at 90°C, keep the temperature at 90°C for 2.5 h to obtain the crude product of the high molecular emulsion breaker; the reaction equation is as follows:

[0060]

[0061] (4) Add n-hexane to the crude product of the high molecular emulsion breaker to carry out extraction, separate two phases, collect the lower target product, and carry out distillation at 150°C under reduced pressure to remove the solvent, thereby obtaining the high molecular emulsion breaker 3#, and the molecular weight is 26375.

[0062] Example 4

[0063] A method for preparing a high molecular emulsion breaker, comprising:

[0064] (1) Put 250 g polyethylene imine (PEI-10000) and 1.2 g potassium hydroxide into a polymerization reactor, start to heat and stir, and carry out vacuum and nitrogen replacement to ensure that the reactor is free of water and oxygen, slowly pass 200 g propylene oxide at 135°C, after the reaction of the propylene oxide is completed, reduce the temperature to 125°C, slowly pass 100 g ethylene oxide, and after the reaction is completed, form a polyether; the reaction equation is the same as that in step (1) of Example 1 (wherein n is 233, a is 138, and b is 91);

[0065] (2) Put 232 g pentaethylene hexamine and 235 g ethylene glycol into a three-necked flask, slowly drop 102 g epoxy chloropropane, control the temperature <30°C during the dropping process, after the dropping process, keep the temperature at 25°C for 16 h to obtain the modifier; the reaction equation is as follows:

[0066]

[0067] (3) Put 350 g polyether synthesized in step (1) into a three-necked flask, slowly drop 10 g modifier synthesized in step (2) at 90°C, keep the temperature at 90°C for 2.5 h to obtain the crude product of the high molecular emulsion breaker; the reaction equation is as follows:

[0068]

[0069] (4) adding n-hexane into the crude polymer demulsifier, carrying out extraction, separating two phases, collecting the lower target product, and carrying out distillation on the target product under the condition of heating to 150℃ and reducing pressure, removing the solvent, and obtaining the polymer demulsifier 4#, the molecular weight of which is 30110.

[0070] Comparative Example 1

[0071] A method for preparing a polymer demulsifier, comprising:

[0072] polyethyleneimine (PEI-8000) 200g, potassium hydroxide 1.8g are added into a polymerization reactor, heating and stirring are started, vacuum and nitrogen replacement are carried out, and no moisture and oxygen are ensured in the reactor, 160g propylene oxide is slowly introduced at 135℃, the reaction of propylene oxide is completed, the temperature is lowered to 125℃, 100g ethylene oxide is slowly introduced, the reaction is completed, the polymer demulsifier D1# is formed, the molecular weight of which is 13983, and the reaction equation is the same as that of step (1) of Example 1.

[0073] Comparative Example 2

[0074] A method for preparing a polymer demulsifier, comprising:

[0075] (1) 189g tetraethylene pentamine, 210g ethylene glycol are added into a three-necked flask, 115g epichlorohydrin is slowly added dropwise, the temperature is controlled to be <30℃ during the dropwise addition, after the dropwise addition is completed, the reaction is carried out at 25℃ for 16h, and a modifier is obtained; the reaction equation is as follows:

[0076]

[0077] (2) polyethyleneimine (PEI-8000) 100g is added into a three-necked flask, the temperature is raised to 90℃, 10g of the modifier synthesized in step (1) is slowly added dropwise, after the dropwise addition is completed, the reaction is carried out at 90℃ for 2.5h, and the polymer demulsifier D2# is obtained, the molecular weight of which is 12294. The reaction equation is as follows (wherein n is 186):

[0078]

[0079] Test Example 1 Crude oil demulsification experiment of a joint station in Shengli Oilfield

[0080] Seven groups of experiments were carried out for the produced liquid oil sample of a joint station in Shengli Oilfield, and the demulsification performance of each group of agent was tested under the same temperature and the same dosage. Among them, the demulsifier sample (polyamine as the starting agent type polyoxypropylene polyoxyethylene ether, molecular weight 4500) currently in use in the joint station, the high molecular demulsifiers obtained in Examples 1-4 are represented by codes 1#, 2#, 3# and 4#, the high molecular demulsifiers obtained in Comparative Examples 1-2 are represented by codes D1# and D2#, the water content of the oil sample is 35%, the dehydration temperature is 50℃, and the oil volume is 80 mL. The test results of each agent are shown in Table 1:

[0081] Table 1 Dehydration data of demulsifiers

[0082]

[0083] According to Table 1, the high molecular demulsifiers 1#-4# provided in Examples 1-4 have high dehydration rates, all reaching the index of dehydration rate ≥90% required in the field, and the water phase cleanliness of the separated water is higher than the field product index. The products of Examples can achieve water purification while dehydrating, and by centrifuging the upper crude oil after dehydration, the high molecular demulsifiers 1#-4# can achieve dehydration and dryness, reaching the requirement of upper water content <0.8. Among them, the high molecular demulsifier 3# has the best effect, with a dehydration rate of 95.7% and an upper water content of 0.3.

[0084] Compared with the high molecular demulsifier D1# provided in Comparative Example 1, the high molecular demulsifiers 1#-4# provided in Examples 1-4 all introduce modifiers, and both the demulsification effect and the water purification effect are greatly improved.

[0085] Compared with the high molecular demulsifier D2# provided in Comparative Example 2, the high molecular demulsifiers 1#-4# provided in Examples 1-4 and the structure of the field demulsifier sample all have block polyether formed by propylene oxide and ethylene oxide, which is directionally arranged and easy to adsorb the oil-water interface, weaken the strength of the original interface film, and make the interface film easy to break, thereby realizing oil-water separation.

[0086] The high molecular demulsifier 3# provided in Example 3 was characterized by FTIR, and it was found that Figure 1 the peak at 1100 cm -1 -1 is the stretching vibration peak of ether bond (C-O-C), proving that propylene oxide and ethylene oxide undergo ring-opening polymerization with polyethyleneimine, the wide and strong peak at 3300-3500 cm -1 -1 is the stretching vibration absorption peak of tetraethylene pentamine amine group (N-H), there is no peak at 910 cm -1 -1, proving that there is no epoxy group and the epichlorohydrin has reacted with tetraethylene pentamine, and the peak at 736 cm -1 -1 is the characteristic absorption peak of quaternary ammonium substitution, proving that the quaternary amination reaction has occurred.

[0087] Figure 2 The molecular weight of the high molecular demulsifier 3# was measured, and the weight average molecular weight of the high molecular demulsifier 3# provided in Example 3# reached 26375.

[0088] The above merely provides examples of the present application, and the protection scope of the present application is not limited by these specific examples, but is determined by the claims of the present application. Various modifications and changes can be made to the present application by those skilled in the art. Any modification, equivalent replacement, improvement, etc. within the technical thought and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A high molecular emulsion breaker, characterized by, Having a structure as shown in formula (I): Formula (I); Wherein, R is selected from any one of NH2-(CH2CH2NH)m-CH2CH2, m represents an integer of 1-4; n represents an integer of 25-600; a represents an integer of 60-200; b represents an integer of 40-150.

2. The polymeric demulsifier according to claim 1, characterized in that, The molecular weight of the high molecular emulsion breaker is 10000-35000.

3. A process for the preparation of the polymeric demulsifier according to any one of claims 1 to 2, characterized in that, Comprising: (1) adding polyethyleneimine and basic catalyst into a reaction kettle, warming and stirring, and performing vacuum and nitrogen replacement to ensure that the reaction kettle is free of moisture and oxygen, then passing in propylene oxide at 130-140℃, cooling to 120-130℃ after the reaction is completed, and then passing in ethylene oxide, to obtain polyether; (2) adding polyethylene polyamine and solvent into a flask, then adding dropwise epichlorohydrin, controlling the temperature <30℃ during the dropwise addition process, and after the dropwise addition is completed, performing incubation reaction at 20-30℃ for 14-18h, to obtain a modifier; (3) adding polyether into a flask, warming to 85-95℃, then adding dropwise the modifier, after the dropwise addition is completed, incubating for 2-3h, to obtain a high molecular emulsion breaker crude product; (4) adding n-hexane into the high molecular emulsion breaker crude product, performing extraction, separating two phases, collecting the lower target product, and performing warming to 140-160℃ reduced pressure distillation on the target product to remove the solvent, to obtain the high molecular emulsion breaker.

4. The method of claim 3, wherein, In step (1), the mass ratio of the polyethyleneimine, propylene oxide and ethylene oxide is 1:(0.8-10):(0.4-8). The basic catalyst accounts for 0.3-1wt% of the total mass of propylene oxide and ethylene oxide.

5. The method of claim 3, wherein, In step (1), the basic catalyst is selected from any one of potassium hydroxide, sodium hydroxide and potassium methoxide.

6. The method of claim 3, wherein, In step (1), the molecular weight of the polyethyleneimine is 1000-25000.

7. The method of claim 3, wherein, In step (2), the molar ratio of the polyethylene polyamine to epichlorohydrin is 1:(1-2).

8. The method of claim 3, wherein, In step (2), the polyethylene polyamine is selected from any one of diethylene triamine, triethylene tetramine, tetraethylene pentamine and pentaethylene hexamine; The solvent is selected from any one of ethanol, ethylene glycol and ethylene glycol monobutyl ether.

9. The method of claim 3, wherein, In step (3), the mass ratio of the modifier to polyether is 1:(10-50).

10. The use of the high molecular emulsion breaker in any one of claims 1-2 in the process of demulsification and dehydration of produced liquid crude oil, and the dosage of the high molecular emulsion breaker is 90-110ppm.

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