A hydrate polymerization inhibitor, its preparation method and application

Abstract

The application discloses a hydrate polymerization inhibitor, a preparation method and application thereof. The hydrate polymerization inhibitor comprises a pretreated asphaltene mixture, an active treatment agent and a synergist, wherein the pretreated asphaltene mixture comprises asphaltene, an acid anhydride treatment agent, a reaction initiator and a dissolving dispersant. The hydrate polymerization inhibitor can effectively hinder hydrate particle aggregation, prevent hydrate pipe blockage, has a small influence on crude oil properties, and has the advantages of low cost and high efficiency, and can provide a feasible method for risk management of hydrates in a subsea multiphase pipeline in a petroleum and natural gas conveying process.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of oil and gas production, in particular to a complex hydrate inhibitor based on asphaltene, a preparation method and application thereof. BACKGROUND

[0002] The study of hydrate began in the early nineteenth century, and is currently attracting attention in many fields, such as pipeline flow safety, energy saving and energy storage, low-carbon technology by hydrate method, and gas storage. In the field of pipeline flow safety, hydrate can appear in the multiphase pipeline under suitable conditions and threaten the safe operation of the pipeline. Due to the presence of natural surfactants in crude oil, oil-water two-phase in the submarine pipeline often appears in the form of water-in-oil emulsion. When the temperature, pressure and system composition in the pipeline reach the hydrate formation conditions, water droplets will be transformed into hydrate particles at the end of the induction period.

[0003] The generated hydrate particles will aggregate under the action of capillary liquid bridge force and can form particle or block objects, and the hydrate particles can also deposit on the inner wall of the pipeline, which seriously threatens the safe operation of the pipeline and can even block the pipeline. In order to prevent the generated hydrate from blocking the pipeline, the management method of hydrate has been paid more and more attention in the process of oil and gas production and transportation.

[0004] The traditional hydrate management and control method mainly adds a thermodynamic inhibitor mainly composed of methanol or ethylene glycol. This method can avoid the occurrence of hydrate by changing the thermodynamic conditions of hydrate formation. With the consideration of economic and environmental factors, low-dose kinetic inhibitors have gradually begun to be applied. Kinetic inhibitors mainly avoid hydrate blockage by prolonging the induction period of hydrate. However, the nucleation of hydrate is a random process, and it is uncertain to completely avoid the generation of hydrate by using hydrate inhibitors. With the continuous deepening of research, the management measures of hydrate have gradually changed from completely avoiding the generation of hydrate to risk control. The risk control strategy of hydrate is to make the hydrate flow in the form of relatively stable slurry, which broadens the method of hydrate management and ensures the safe operation of the pipeline. The key to the risk control strategy of hydrate is the application of low-dose hydrate inhibitors. Hydrate inhibitors can adsorb on the surface of water droplets to stabilize the emulsion before the formation of hydrate, thereby reducing the particle size of the generated hydrate particles. At the same time, the inhibitor can inhibit the aggregation of hydrate, so that it is dispersed in the form of particles in the liquid phase for stable transportation, and will not be blocked in a large amount.

[0005] CN105090747B discloses a complex hydrate inhibitor containing rhamnolipid, which is prepared by compounding rhamnolipid biosurfactant and polyol nonionic surfactant, and the hydrate inhibitor is prepared by changing the surface hydrophilicity of hydrate to inhibit the aggregation of hydrate particles, but a large amount of surfactant needs to be added, which increases the pipeline operation cost and the difficulty of oil-gas-water three-phase separation.

[0006] CN107314245B discloses a complex hydrate inhibitor containing lecithin and its use, which is prepared by mixing polyol nonionic surfactant, lecithin zwitterionic surfactant and complex synergist, but the addition of a large amount of reagent increases the liquid viscosity and operating friction, and increases the energy consumption in the pipeline operation process.

[0007] The hydrate inhibitors used at present are mainly amphiphilic surfactants, and typical hydrate inhibitors include quaternary ammonium salt surfactants and sorbitan. The hydrate inhibitor can be adsorbed on the surface of water droplets and hydrate particles, reduce the capillary liquid bridge action between hydrate particles and disperse them. The quaternary ammonium salt hydrate inhibitor has good dispersing performance on hydrate particles, but it is toxic and not easy to degrade, which limits its large-scale promotion to a certain extent. Therefore, it is of great significance to develop a new type of hydrate inhibitor for the field of hydrate management. SUMMARY

[0008] In view of the deficiencies of the prior art, the present application provides a hydrate inhibitor, a preparation method and application thereof. The hydrate inhibitor of the present application can effectively hinder the aggregation of hydrate particles, prevent hydrate from plugging the pipeline, has little effect on the properties of crude oil, and has the advantages of low cost and high efficiency, and can provide a feasible method for risk management of hydrate in subsea multiphase pipelines during oil and natural gas transportation.

[0009] The present application provides a hydrate inhibitor, which comprises: a pretreated asphaltene mixture, an active treatment agent and a synergist, wherein the pretreated asphaltene mixture comprises asphaltene, an acid anhydride treatment agent, a reaction initiator and a dissolution dispersant.

[0010] Further, the mass ratio of the pretreated asphaltene mixture, the active treatment agent and the synergist is 40:(0.01-0.1):(0.1-1).

[0011] Further, in the pretreated asphaltene mixture, the mass ratio of asphaltene, acid anhydride treatment agent, reaction initiator and dissolution dispersant is 1:(0.1-0.5):(0.01-0.05):(5-50).

[0012] Further, the asphaltene can be extracted from vacuum residue, crude oil or asphalt, and the extraction step can refer to NB / SH / T0509-2010 "Determination of Four Components of Petroleum Asphalt".

[0013] Further, the properties of the asphaltene include: a molecular weight of 500-8000, preferably 1000-5000; a mass content of carbon element of 80wt%-88wt%; a mass content of nitrogen element of 0.5wt%-2.5wt%; a mass content of hydrogen element of 4wt%-12wt%; a mass content of sulfur element of 1.0wt%-8.0wt%; a mass content of oxygen element of 0.5wt%-5.0wt%; and a hydrogen-carbon molar ratio of 1.0-1.5, preferably 1.0-1.2.

[0014] Further, the anhydride treating agent is one or more of maleic anhydride, polyisobutylene succinic anhydride, dodecenyl succinic anhydride, tung oil anhydride, polyazelaic anhydride, polyglutaric anhydride, polyitaconic anhydride or hydrolyzed polymaleic anhydride.

[0015] Further, the reaction initiator is one or more of dicumyl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, sodium metabisulfite, azobisisobutyronitrile or azobisisoheptyl nitrile.

[0016] Further, the dissolving dispersing agent is one or more of hydrocarbon solvents such as toluene, benzene, xylene, carbon disulfide, chloroform, carbon tetrachloride and methylnaphthalene.

[0017] Further, the active treating agent is one or more of polyvinyl alcohol (molecular weight of 10000-150000) or polyethyleneimine (molecular weight of 1000-10000).

[0018] Further, the synergist is one or more of non-ionic surfactants Span20, Span40, Span60 or Span80.

[0019] The second aspect of the present application provides a preparation method of the above hydrate polymerization inhibitor, comprising the following steps:

[0020] (1) dispersing the asphaltene in a dissolving dispersing agent, adding an anhydride treating agent and a reaction initiator, and treating under stirring to obtain a pretreated asphaltene mixture;

[0021] (2) mixing the pretreated asphaltene mixture obtained in step (1) with an active treating agent and a synergist, and stirring to obtain a hydrate polymerization inhibitor.

[0022] Further, the step (1) adopts ultrasonic oscillation to dissolve and disperse the asphaltene in the dissolving dispersant. The oscillation time is 30-60 minutes, the temperature is 25-60 DEG C, and the oscillation frequency is 20-40 MHz.

[0023] Further, in the step (1), the stirring rate is 100-800 rpm, the treatment time is 3-5 hours, and the treatment temperature is 60-90 DEG C.

[0024] Further, in the step (2), the stirring rate is 200-800 rpm, the stirring temperature is 25-60 DEG C, and the stirring time is 10-30 minutes.

[0025] The third aspect of the present application provides a use of the hydrate inhibitor in an oil-water system.

[0026] Further, the water content in the oil-water system is 5-50 wt%, and the oil content is 50-95 wt%. The temperature of the oil-water system is-10-50 DEG C, and the pressure is 0.1-20.0 MPa.

[0027] Further, the added amount of the hydrate inhibitor is 0.5-3.5% of the oil phase in the oil-water system.

[0028] Compared with the prior art, the present application has the following advantages:

[0029] (1) The hydrate inhibitor based on asphaltene in the present application can obviously inhibit the coalescence of water droplets before hydrate formation, and hinder the aggregation of hydrate particles, so that the hydrate exists in the system in the form of particles, effectively avoids the hydrate blockage, is beneficial to the risk management of hydrate, and can ensure the safe operation of the oil-water multiphase pipeline.

[0030] (2) The hydrate inhibitor in the present application has stronger reactivity by pretreating the asphaltene, and improves the hydrophilicity and the inhibition effect of the asphaltene itself. The inhibition effect of the asphaltene and the synergistic agent on the hydrate is enhanced by compounding the components, so that the content of the chemical emulsifier in the inhibitor is greatly reduced, the hydrate aggregation is effectively prevented, and the influence of the inhibitor on the pipeline operation and subsequent oil-water separation is reduced.

[0031] (3) The hydrate inhibitor in the present application mainly extracts asphaltene from low-cost residual oil, has low cost, improves the economic benefit of residual oil, has significant social benefits, and has simple preparation method, obvious effect, and is beneficial to popularization and application in oilfield sites.

[0032] (4) The hydrate inhibitor of the present application has less required mass in application, does not need to inject a large amount of chemical reagent additionally, has less influence on the properties of crude oil, and reduces the difficulty of subsequent treatment of the crude oil. BRIEF DESCRIPTION OF DRAWINGS

[0033] Figure 1 The microscopic picture of the water droplet particle size in the oil-water system in Comparative Example 1;

[0034] Figure 2 The microscopic picture of the water droplet particle size in the oil-water system in Comparative Example 4;

[0035] Figure 3 The microscopic picture of the water droplet particle size in the oil-water system in Example 1. DETAILED DESCRIPTION

[0036] The present application will be further described in detail by specific examples, and the described examples are only used to explain the present application, but not used to limit the protection scope of the present application.

[0037] The Nikon OPTIPHOT2-POL type polarizing microscope is used to measure the water droplet particle size in the examples and comparative examples.

[0038] Comparative Example 1

[0039] The purpose of the present comparative example is to measure the dispersed particle size of the water droplet in the oil phase before the hydrate is generated. In the water-in-oil system, the water phase is dispersed in the oil phase in the form of droplets, and the water droplet gradually converts into hydrate particles when the hydrate is generated. Therefore, the particle size of the water droplet determines the particle size of the generated hydrate particles.

[0040] The optical microscope is used to observe the water droplet particle size in the present comparative example and other specific test examples of the water-in-oil system.

[0041] The specific steps of measuring the water droplet particle size by using the above optical microscope are as follows:

[0042] (1) 600 mL of diesel oil and 200 mL of deionized water are sequentially poured into a 2L beaker, and the beaker is placed in a temperature-controlled water bath.

[0043] (2) The oil-water system is stirred at a stirring speed of 1000 rpm, a stirring temperature of 4℃, and a stirring time of 15 min.

[0044] (3) After the stirring is completed, an appropriate amount of liquid is taken by using a sampling tube and placed on a glass slide to prepare an observation sample, the objective lens is selected to be 10x, and the observation and photography are performed at 4℃. Five different positions of each sample are observed and photographed.

[0045] The water droplet particle size test results are as follows: Figure 1As shown, because the present comparative example does not add a hydrate polymerization inhibitor, the water droplets in the oil-water system have a large particle size, and after the stirring is stopped, the water droplets in the beaker will quickly coalesce, and within 10 min, a clear two-phase oil-water layer is formed.

[0046] Comparative Example 2

[0047] The present comparative example uses a high-pressure stirred hydrate reactor to evaluate the hydrate particle aggregation effect, which mainly includes a high-pressure reactor body, a temperature control system, a pressure control system, a stirring system, a parameter measurement and data acquisition system. The water-in-oil system is subjected to a hydrate generation process in the high-pressure reactor chamber, the temperature is controlled by a circulating water bath, the pressure is controlled by a high-pressure gas cylinder and a regulating valve, and the stirring is achieved by a magnetic stirrer.

[0048] The specific steps for the evaluation experiment using the above high-pressure stirred hydrate reactor are as follows:

[0049] (1) Pour 600 mL of diesel oil and 200 mL of deionized water into a 2 L beaker in sequence, and stir at a speed of 1000 rpm for 15 min to obtain an oil-water mixture.

[0050] (2) After cleaning the high-pressure reactor chamber, pour the oil-water mixture into it and seal it, and then replace the residual air in the reactor with a vacuum pump.

[0051] (3) Turn on the stirring paddle and data acquisition system, set the stirring speed to 400 rpm, and stir the liquid in the reactor.

[0052] (4) Open the gas cylinder and the gas inlet valve, gradually introduce gas into the high-pressure reactor to 4.0 MPa, and then close the gas cylinder and the gas inlet valve to maintain the high-pressure environment of the system.

[0053] (5) Set the water bath temperature, gradually reduce the temperature in the reactor from room temperature to 4°C, and maintain the water bath temperature after reaching the specified temperature.

[0054] (6) When the temperature in the system suddenly rises, it indicates that the hydrate begins to form, and the water droplets in the oil-water system gradually transform into hydrate particles.

[0055] (7) As the water droplets transform, the temperature in the system gradually decreases under the action of the circulating water bath, and the pressure also gradually decreases due to the consumption of gas. When there is no change in the pressure and temperature in the system within 30 min, the hydrate formation is complete.

[0056] (8) After the hydrate is formed, stop stirring, reopen the stirring paddle after 1 h, and observe whether the hydrate particles aggregate and affect the stirring paddle, then open the exhaust valve to release the pressure in the system, and when the pressure reaches normal pressure, open the high-pressure reactor to take out the hydrate in the reactor, and observe the state of the hydrate.

[0057] The hydrate inhibitor can make the hydrate exist in the oil phase in the form of small particle size particles when the hydrate inhibitor works, the stirring paddle can be restarted smoothly after the stirring is stopped, and the hydrate can be observed in the form of particles after the autoclave is opened, and no block is formed.

[0058] In the present comparative example, no hydrate inhibitor is added, and the hydrate can be generated rapidly after the temperature and pressure meet the conditions, and the rotation of the stirring paddle is blocked when the stirring is stopped for 1 h. After the stirring paddle is turned off and depressurized, it is observed that the hydrate particles in the autoclave are all gathered together to form a block-shaped whole. It is shown that when no hydrate inhibitor is added, the hydrate particles are significantly gathered under the action of capillary liquid bridge force, and it is extremely likely to block the pipeline in the engineering site.

[0059] Comparative Example 3

[0060] The present comparative example uses a high-pressure swing reaction device to evaluate the effect of the hydrate inhibitor, and the structure includes a swing autoclave main body, a temperature control system, a pressure control system, a swing system, a parameter measurement and data acquisition system. The swing autoclave cavity is a transparent tube, and at the same time, a metal ball is placed in the swing autoclave cavity for stirring the fluid. When the hydrate particles are gathered, the reciprocating swing movement of the metal ball will be hindered, and when the hydrate particle aggregates are large enough, the small ball will stop moving.

[0061] The specific steps for evaluation experiment using the above high-pressure stirring type hydrate reaction autoclave are as follows:

[0062] (1) 600 mL of diesel oil and 200 mL of deionized water are poured into a 2 L beaker in sequence, and stirred at a speed of 1000 rpm for 15 min to obtain an oil-water mixture.

[0063] (2) After the swing autoclave cavity is cleaned, the oil-water mixture is poured into it and sealed, and then the residual air is replaced.

[0064] (3) The swing motor and the data acquisition system are turned on, and the reaction autoclave cavity is subjected to periodic reciprocating swing movement.

[0065] (4) The gas cylinder and the inlet valve are opened, and the gas is gradually introduced into the autoclave to 3 MPa, and then the gas cylinder and the inlet valve are closed to maintain the high-pressure environment of the system.

[0066] (5) The temperature of the water bath is set, and the temperature in the autoclave is gradually reduced from room temperature to 3℃, and when the specified temperature is reached, the water bath temperature is maintained unchanged.

[0067] (6) When the temperature in the system suddenly rises, it indicates that the hydrate is generated, and the water droplets in the oil-water system gradually change to hydrate particles.

[0068] (7) With the transformation of water droplets, solid particles began to appear in the rocking pot and hinder the movement of metal balls. When the pressure and temperature in the system did not change within 30 minutes, the evaluation experiment ended.

[0069] When the hydrate inhibitor works, the hydrate exists in the oil phase in the form of small particle size particles. The hydrate does not block the pipeline, and the metal ball does not stop moving or the time required for stopping moving is prolonged.

[0070] In the present comparative example, no hydrate inhibitor is added. After the generation of hydrate, the movement speed of the small ball decreases rapidly, and the movement stops within 5 minutes due to the aggregation of hydrate particles to block the pipeline, which shows that the hydrate particles in the oil-water system without adding the polymerization inhibitor can grow and aggregate rapidly.

[0071] Example 1

[0072] (1) The asphaltene (properties are shown in Table 1) is dispersed in toluene by ultrasonic oscillation, the oscillation time is 40 min, the temperature is 40℃, and the oscillation frequency is 40MHz. Then maleic anhydride and dicumyl peroxide are added, wherein the mass ratio of asphaltene, maleic anhydride, dicumyl peroxide and toluene is 1:0.2:0.04:20. The treatment is carried out under stirring at a stirring rate of 300 rpm for 4h at a treatment temperature of 80℃, to obtain a pretreated asphaltene mixture;

[0073] (2) The pretreated asphaltene mixture obtained in step (1) is stirred and mixed with polyethyleneimine (molecular weight 8000) and Span20 at a mass ratio of 40:0.05:0.5 at a stirring rate of 500 rpm for 20 min at a stirring temperature of 40℃, to obtain a hydrate polymerization inhibitor.

[0074] According to the experimental conditions of Comparative Example 1, the compound hydrate polymerization inhibitor is added before stirring, and the addition mass is 1.61% of the mass of the oil phase. The same experimental method is used to observe the water droplet particle size of the oil-water system.

[0075] The observation results are shown in Table 2. Figure 3 As can be seen, the addition of the hydrate polymerization inhibitor significantly reduces the particle size of the water droplets in the oil-water system, and no water droplet aggregation is found within 60 minutes after the oil-water system is stopped stirring, and no obvious oil-water layering phenomenon is found after 12h, which shows that the compound polymerization inhibitor effectively hinders the aggregation of water droplets, and the hydrate particles can flow safely in the pipeline.

[0076] Example 2

[0077] The preparation of the hydrate polymerization inhibitor in this example is the same as that in Example 1.

[0078] The complex hydrate inhibitor provided in this example was added before stirring according to the experimental conditions of Comparative Example 3, and the added mass was 1.61% of the mass of the oil phase. The effect of the hydrate inhibitor was evaluated using the same experimental method.

[0079] Because a kind of asphaltene-based hydrate inhibitor was added to the system, the stirring paddle could be directly and smoothly restarted after stirring for 1 h. After the stirring paddle was turned off and the pressure was released, it was observed that the hydrates in the autoclave existed in the form of dispersed particles, and no block hydrate aggregates appeared, indicating that the complex inhibitor provided in this example could significantly inhibit hydrate particle aggregation.

[0080] Example 3

[0081] The hydrate inhibitor of this example was prepared in the same manner as in Example 1.

[0082] The complex hydrate inhibitor provided in this example was added before stirring according to the experimental conditions of Comparative Example 3, and the added mass was 1.61% of the mass of the oil phase. The effect of the hydrate inhibitor was evaluated using the same experimental method.

[0083] Because a kind of asphaltene-based hydrate inhibitor was added to the system, the stirring paddle could be directly and smoothly restarted after stirring for 1 h. After the stirring paddle was turned off and the pressure was released, it was observed that the hydrates in the autoclave existed in the form of dispersed particles, and no block hydrate aggregates appeared, indicating that the complex inhibitor provided in this example could significantly inhibit hydrate particle aggregation.

[0084] Example 4

[0085] (1) The asphaltene (properties are shown in Table 1) was dispersed in toluene by ultrasonic oscillation, the oscillation time was 30 min, the temperature was 50°C, and the oscillation frequency was 40 MHz. Then, hydrolyzed polymaleic anhydride and dicumyl peroxide were added, and the mass ratio of asphaltene, hydrolyzed polymaleic anhydride, dicumyl peroxide, and toluene was 1:0.5:0.04:40. The pretreated asphaltene mixture was obtained by stirring at a rate of 300 rpm for 4 h at a temperature of 60°C.

[0086] (2) The pretreated asphaltene mixture obtained in step (1) was mixed with polyethyleneimine (molecular weight 10000) and Span 80 at a mass ratio of 40:0.04:0.8 by stirring at a rate of 600 rpm for 20 min at a temperature of 40°C to obtain the hydrate inhibitor.

[0087] The complex hydrate inhibitor provided in this example was added when the emulsion was prepared according to the experimental conditions of Comparative Example 2, and the added mass was 2.03% of the mass of the oil phase. The effect of the hydrate inhibitor was evaluated using the same experimental method using a high-pressure stirred hydrate reactor.

[0088] Due to the addition of a hydrate inhibitor based on asphaltene in the system, the stirring paddle can be directly restarted smoothly after 1 h of stirring. After the stirring paddle is turned off and the pressure is released, it is observed that the hydrate exists in the form of dispersed particles in the autoclave, indicating that the complex inhibitor provided in this example can significantly inhibit the aggregation of hydrate particles, and has a significant inhibition effect.

[0089] Example 5

[0090] The preparation of the hydrate inhibitor in this example is the same as that in Example 4.

[0091] According to the experimental conditions of Comparative Example 3, the complex hydrate inhibitor provided in this example is added before stirring, with an addition mass of 2.03% of the mass of the oil phase. The same experimental method is used to evaluate the effect of the inhibitor.

[0092] Due to the addition of a hydrate inhibitor based on asphaltene in the system, the movement speed of the metal ball decreases after the hydrate is generated, but it can still move back and forth without stopping within 60 min. This indicates that the inhibitor provided in this example can significantly inhibit the aggregation of hydrate particles, and has a significant inhibition effect, which can avoid pipeline blockage.

[0093] Example 6

[0094] (1) Disperse asphaltene (properties see Table 1) in o-xylene by ultrasonic oscillation, with an oscillation time of 40 min, a temperature of 40°C, and an oscillation frequency of 40 MHz. Then add hydrolyzed polymaleic anhydride and dicumyl peroxide, with a mass ratio of asphaltene, hydrolyzed polymaleic anhydride, azobisisobutyronitrile, and o-xylene of 1:0.5:0.08:25. Stir and treat, with a stirring rate of 600 rpm, a treatment time of 4 h, and a treatment temperature of 60°C. Obtain a pretreated asphaltene mixture;

[0095] (2) Stir and mix the pretreated asphaltene mixture obtained in step (1) with polyvinyl alcohol (molecular weight 20000) and Span 80 at a mass ratio of 40:0.08:0.4, with a stirring rate of 500 rpm, a stirring temperature of 40°C, and a stirring time of 30 min. Obtain a hydrate inhibitor.

[0096] According to the experimental conditions of Comparative Example 3, the complex hydrate inhibitor provided in this example is added before stirring, with an addition mass of 3.27% of the mass of the oil phase. The same experimental method is used to evaluate the effect of the inhibitor.

[0097] Due to the addition of the hydrate polymerization inhibitor based on asphaltenes in the system, the movement speed of the metal balls decreases after the formation of the hydrate, but the metal balls can still move back and forth within 60 minutes and do not stop. It is shown that the polymerization inhibitor provided in the embodiment can obviously inhibit the aggregation of the hydrate particles and has a significant polymerization inhibition effect, so that the pipeline can be prevented from being blocked.

[0098] Comparative Example 4

[0099] The hydrate polymerization inhibitor of the comparative example is prepared by the method compared with the method of Example 1, and the only difference is that Span20 is not added in step (2).

[0100] According to the experimental conditions of Comparative Example 1, the hydrate polymerization inhibitor is added before stirring, and the mass of the polymerization inhibitor is 1.61% of the mass of the oil phase. The same experimental method is used to observe the water droplet particle size of the oil-water system.

[0101] The observation results are shown in Table 1. Figure 2 By comparison with the experimental results in Example 1, the water droplet particle size is larger.

[0102] Comparative Example 5

[0103] The hydrate polymerization inhibitor of the comparative example is prepared by the method compared with the method of Example 1, and the only difference is that Span20 is not added in step (2).

[0104] According to the experimental conditions of Comparative Example 2, the hydrate polymerization inhibitor is added before stirring, and the mass of the polymerization inhibitor is 1.61% of the mass of the oil phase. The same experimental method is used to evaluate the aggregation of the hydrate.

[0105] After the stirring is stopped for 1 hour, the stirring paddle can be slowly restarted. After the stirring paddle is turned off and the pressure is released, it is observed that the hydrate in the autoclave exists in the form of broken blocks, which is more likely to be aggregated into blocks than the hydrate in Example 2.

[0106] Comparative Example 6

[0107] The hydrate polymerization inhibitor of the comparative example is prepared by the method compared with the method of Example 1, and the only difference is that Span20 is not added in step (2).

[0108] According to the experimental conditions of Comparative Example 3, the hydrate polymerization inhibitor is added before stirring, and the mass of the polymerization inhibitor is 1.61% of the mass of the oil phase. The same experimental method is used to evaluate the aggregation of the hydrate.

[0109] The results show that the movement speed of the small balls decreases rapidly after the formation of the hydrate, and the movement stops after 13 minutes. By comparison with Example 3, it is known that the hydrate in the comparative example is more likely to be aggregated and block the pipeline.

[0110] Comparative Example 7

[0111] The hydrate inhibitor of the comparative example was prepared by the same method as in Example 1, except that the asphaltene was not pretreated and was directly mixed with polyethyleneimine (molecular weight 8000) and Span 20 in a mass ratio of 40:0.05:0.5.

[0112] The hydrate inhibitor was added before stirring according to the experimental conditions of Comparative Example 2, and the mass of the inhibitor was 1.61% of the mass of the oil phase. The evaluation of the hydrate aggregation effect was performed by the same experimental method.

[0113] After the stirring was stopped for 1 h, the stirring paddle was slowly restarted. After the stirring paddle was turned off and the pressure was released, it was observed that the hydrates in the autoclave existed in the form of broken chunks and were more likely to aggregate into chunks than the hydrates in Example 2.

[0114] Comparative Example 8

[0115] The hydrate inhibitor of the comparative example was prepared by the same method as in Example 1, except that maleic anhydride was not added in step (1) for preparing the pretreated asphaltene mixture.

[0116] The hydrate inhibitor was added before stirring according to the experimental conditions of Comparative Example 2, and the mass of the inhibitor was 1.61% of the mass of the oil phase. The evaluation of the hydrate aggregation effect was performed by the same experimental method.

[0117] The results showed that after the stirring was stopped for 1 h, the stirring paddle was slowly restarted. After the stirring paddle was turned off and the pressure was released, it was observed that the hydrates in the autoclave existed in the form of broken chunks.

[0118] Table 1 Properties of the asphaltene used in the examples

[0119] Molecular weight 3180 Carbon element mass content / wt% 82.8 Nitrogen element mass content / wt% 1.9 Hydrogen element mass content / wt% 7.7 Sulfur element mass content / wt% 5.4 Oxygen element mass content / wt% 2.2 Hydrogen carbon molar ratio 1.11

[0120] The preferred embodiments of the application are described in detail above, but the application is not limited thereto. Within the technical concept of the application, various simple modifications can be made to the technical solutions of the application, including the combination of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as disclosed by the application and fall within the protection scope of the application.

Claims

1. A hydrate inhibitor, characterized by: The hydrate inhibitor comprises: a pretreated asphaltene mixture material, an active treatment agent, and a synergist, wherein the pretreated asphaltene mixture material comprises asphaltene, an anhydride treatment agent, a reaction initiator, and a dissolving dispersant; The mass ratio of the pretreated asphaltene mixture material, the active treatment agent, and the synergist is 40: (0.01-0.1): (0.1-1); In the pretreated asphaltene mixture material, the mass ratio of asphaltene, the anhydride treatment agent, the reaction initiator, and the dissolving dispersant is 1: (0.1-0.5): (0.01-0.05): (5-50); The anhydride treatment agent is one or more of maleic anhydride, polyisobutylene succinic anhydride, dodecenyl succinic anhydride, tung oil anhydride, polyazelaic anhydride, polyglutaric anhydride, polyethanedioic anhydride, or hydrolyzed polymaleic anhydride; The active treatment agent is one or more of polyvinyl alcohol with a molecular weight of 10,000-150,000 or polyethyleneimine with a molecular weight of 1,000-10,000; The synergist is one or more of non-ionic surfactants Span 20, Span 40, Span 60, or Span 80.

2. The hydrate polymerization inhibitor of claim 1, wherein: The properties of the asphaltene include: a molecular weight of 500-8,000, a carbon element mass content of 80wt%-88wt%, a nitrogen element mass content of 0.5wt%-2.5wt%, a hydrogen element mass content of 4wt%-12wt%, a sulfur element mass content of 1.0wt%-8.0wt%, an oxygen element mass content of 0.5wt%-5.0wt%, and a hydrogen-carbon molar ratio of 1.0-1.

5.

3. The hydrate polymerization inhibitor of claim 2, wherein: The properties of the asphaltene include: a molecular weight of 1,000-5,000, and a hydrogen-carbon molar ratio of 1.0-1.

2.

4. The hydrate polymerization inhibitor of claim 1, wherein: The reaction initiator is one or more of dicumyl peroxide, tert-butyl hydroperoxide, benzoyl peroxide, sodium metabisulfite, azobis isobutyronitrile, or azobis isohexyl nitrile; And / or, the dissolving dispersant is one or more of toluene, benzene, xylene, carbon disulfide, trichloromethane, carbon tetrachloride, and methylnaphthalene.

5. The preparation method of the hydrate inhibitor according to any one of claims 1-4, comprising the following steps: (1) dispersing asphaltene in a dissolving dispersant, adding an anhydride treatment agent and a reaction initiator, and treating under stirring to obtain a pretreated asphaltene mixture material; (2) mixing the pretreated asphaltene mixture material obtained in step (1) with an active treatment agent and a synergist, and stirring to obtain a hydrate inhibitor.

6. The method of claim 5, wherein: In step (1), ultrasonic oscillation is used to dissolve and disperse the asphaltene in the dissolving dispersant; the oscillation time is 30min-60min, the temperature is 25℃-60℃, and the oscillation frequency is 20-40MHz.

7. The method of claim 5, wherein: In step (1), the stirring rate is 100-800rpm; the treatment time is 3-5h, and the treatment temperature is 60℃-90℃.

8. The method of claim 5, wherein: In step (2), the stirring rate is 200rpm-800rpm, the stirring temperature is 25℃-60℃, and the stirring time is 10min-30min.

9. Use of the hydrate inhibitor according to any one of claims 1-4 or the hydrate inhibitor prepared according to any one of claims 5-8 in an oil-water system.

10. Use according to claim 9, characterized in that: The added mass of the hydrate inhibitor is 0.5%-3.5% of the mass of the oil phase in the oil-water system.

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