Quaternary ammonium salt type environment-friendly high-temperature-resistant filtrate reducer and preparation method thereof

Abstract

The invention provides a quaternary ammonium salt type environment-friendly high-temperature-resistant filtrate reducer and a preparation method thereof. The preparation method of the quaternary ammonium salt type environment-friendly high-temperature-resistant filtrate reducer comprises the following steps: mixing and dissolving acrylamide, N-vinyl pyrrolidone, allyl imidazole and a chain transfer agent to obtain a first solution; adding an initiator into the first solution for reaction at 55-60 DEG C for 6-8 hours to obtain a second solution; and adding 2-chloro-3-hydracrylic acid and 4-dimethylaminopyridine into the second solution to react at 85-90 DEG C for 48-50 hours, and freezing and recrystallizing to obtain the filtrate reducer. The quaternary ammonium salt type environment-friendly high-temperature-resistant filtrate reducer is obtained by the method. The quaternary ammonium salt type environment-friendly high-temperature-resistant filtrate reducer provided by the invention is good in high-temperature resistance, can resist the temperature of 180 DEG C, and is degradable and environment-friendly.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically to a quaternary ammonium salt type environmentally friendly high-temperature resistant filtration reducer and its preparation method. Background Technology

[0002] To minimize the adverse environmental impact of drilling fluids and implement source pollution control, researching environmentally friendly water-based drilling fluid treatment agents is of great significance. As oil exploration and development gradually advances into deeper formations, the encountered formations become increasingly complex, placing higher demands on the temperature resistance of drilling fluids. Currently, commonly used environmentally friendly filtration reducers, such as cellulose and starch-based filtration reducers, typically have a temperature resistance of less than 120℃, which cannot meet the future development trends of drilling fluids. Therefore, to meet the future needs of drilling fluid development, it is urgent to develop filtration reducers with better high-temperature resistance and greater environmental friendliness. Thus, providing a quaternary ammonium salt-type environmentally friendly high-temperature resistant filtration reducer and its preparation method is of great importance.

[0003] Chinese patent application number CN202110550571.2, entitled "A High-Temperature, Salt-Resistant, Anti-Collapse, and Filtration Loss Reducing Agent and Its Preparation Method," discloses a high-temperature, salt-resistant, anti-collapse, and filtration loss reducing agent and its preparation method. This filtration loss reducing agent is polymerized from lignin degradation solution, maleic anhydride, sodium p-styrene sulfonate, and dimethyl diallyl ammonium chloride under the action of an initiator and a crosslinking agent. By immobilizing lignin degraded by ferulic acid esterase, the molecular weight decreases and the number of active sites increases, making it easier to react with other monomers. The resulting compound has good solubility, good compatibility with other drilling fluid additives, and outstanding high-temperature, salt-resistant, and anti-collapse properties. However, this filtration loss reducing agent differs from the filtration loss reducing agent in this application, and their preparation methods also differ. Summary of the Invention

[0004] In view of the shortcomings of the prior art, the purpose of this invention is to solve one or more problems existing in the prior art. For example, one objective of this invention is to provide a quaternary ammonium salt-type environmentally friendly high-temperature filtration reducer with good high-temperature resistance and environmental friendliness.

[0005] To achieve the above objectives, the present invention provides a quaternary ammonium salt-type environmentally friendly high-temperature filtration loss reducing agent, wherein the structural formula of the quaternary ammonium salt-type environmentally friendly high-temperature filtration loss reducing agent may include the following structural unit (I):

[0006]

[0007] According to one or more exemplary embodiments of one aspect of the present invention, the formulation of the quaternary ammonium salt type environmentally friendly high-temperature filtration loss reducing agent may include: acrylamide, N-vinylpyrrolidone, allyl imidazole, 2-chloro-3-hydroxypropionic acid, chain transfer agent, initiator and 4-dimethylaminopyridine.

[0008] Another aspect of the present invention provides a method for preparing the quaternary ammonium salt type environmentally friendly high-temperature filtration loss reducing agent as described above. The method may include: mixing and dissolving acrylamide, N-vinylpyrrolidone, allyl imidazole and a chain transfer agent to obtain a first solution; adding an initiator to the first solution and reacting at 55-60°C for 6-8 hours to obtain a second solution; adding 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine to the second solution and reacting at 85-90°C for 48-50 hours, followed by freezing and recrystallization to obtain the filtration loss reducing agent.

[0009] According to one or more exemplary embodiments of another aspect of the present invention, the material components in the method may include, by mass percentage: 25-30% acrylamide, 10-15% N-vinylpyrrolidone, 10-15% allyl imidazole, 15-20% 2-chloro-3-hydroxypropionic acid, 4-6% chain transfer agent, 0.2-0.4% initiator, and 0.1-0.2% 4-dimethylaminopyridine.

[0010] According to one or more exemplary embodiments of another aspect of the present invention, the initiator may include any one of azobisisobutyrazoline hydrochloride, azobisisobutyramidine hydrochloride, ammonium persulfate, potassium persulfate, and azobisisobutyronitrile.

[0011] According to one or more exemplary embodiments of another aspect of the present invention, the chain transfer agent may include any one of sodium formate, sodium hypophosphite, and sodium hypophosphite.

[0012] According to one or more exemplary embodiments of another aspect of the present invention, the reaction of adding the initiator may include: cooling to room temperature after the reaction is completed; the reaction of adding 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine to the second solution may include: cooling to room temperature after the reaction is completed.

[0013] According to one or more exemplary embodiments of another aspect of the present invention, the solvent used for the dissolution may include anhydrous ethanol.

[0014] According to one or more exemplary embodiments of another aspect of the present invention, after dissolution, the first solution may be purged of air before the initiator is added; when 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine are added to the second solution for reaction, the current solution may be purged of air.

[0015] According to one or more exemplary embodiments of another aspect of the present invention, the air purging may include: introducing an inert gas to purge air for 20 to 30 minutes.

[0016] Compared with the prior art, the beneficial effects of the present invention include at least one of the following:

[0017] (1) The quaternary ammonium salt type environmentally friendly high temperature filtration loss reducer proposed in this invention has better high temperature resistance and is more environmentally friendly, which is in line with the future development trend of drilling fluid.

[0018] (2) The quaternary ammonium salt-type environmentally friendly high-temperature filtration reducer proposed in this invention has rigid cyclic groups with strong temperature resistance, which improves the temperature resistance of the polymer. Through the overall design of the molecular structure, copolymerization, and grafting modification, the cyclic structure, quaternary ammonium group, hydroxyl group and carboxyl group work together to effectively improve the comprehensive performance of the filtration reducer under high temperature conditions of 180℃, such as temperature resistance, hydration capacity and high temperature adsorption capacity. For example, when the quaternary ammonium group is used as a cationic group, it can effectively enhance the adsorption capacity and play a long-term stabilizing role; the hydroxyl group is a non-ionic adsorption group. When the treatment agent is dispersed in the drilling fluid, it can be adsorbed onto the surface of clay particles through this group. At the same time, it also has a certain hydration effect to obtain a better stable colloid and maintain the comprehensive performance of the drilling fluid; the carboxyl group can form a strong solvent layer in the polymer chain, thereby playing a role in salt resistance, temperature resistance and pollution resistance.

[0019] (3) The molecular structure of conventional oil and gas field drilling fluid treatment agents is related to their environmental impact. Regarding degradability: aromatic rings are difficult to break, making biodegradation difficult; drilling fluid treatment agents containing aromatic rings in their molecular structure have low acute biotoxicity EC50 values ​​and high toxicity. In this invention, by independently designing the types of functional groups and the molecular skeleton structure, the introduction of functional groups such as aromatic rings that have a significant impact on environmental performance into the molecular structure is avoided, providing a novel high-temperature resistant, environmentally friendly filtration reduction agent. Attached Figure Description

[0020] The above and other objects and features of the present invention will become clearer from the following description taken in conjunction with the accompanying drawings, in which:

[0021] Figure 1 The infrared spectrum of the filtration reduction agent of Example 1 of the present invention is shown;

[0022] Figure 2 The photoelectron spectrum of the filter loss reducing agent of Example 7 of the present invention is shown;

[0023] Figure 3 Another photoelectron spectrum of the filter loss reducing agent of Example 7 of the present invention is shown;

[0024] Figure 4The following are shown: Example 6 of the present invention, a filtration loss reducer, and three existing filtration loss reducers added to a base slurry sample, and the filtration loss of the base slurry sample. Detailed Implementation

[0025] In the following description, an environmentally friendly high-temperature filtration reducer of the present invention and its preparation method will be described in detail with reference to the accompanying drawings and exemplary embodiments.

[0026] In the description of this application, it should be understood that the terms "first," "second," "I," etc., are used merely for convenience of description and distinction, and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. In the description of this invention, unless otherwise stated, "a plurality of" means two or more. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] Exemplary Example 1

[0028] This exemplary embodiment provides a method for preparing a quaternary ammonium salt-type environmentally friendly high-temperature resistant filtration loss reducer.

[0029] The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature filtration loss reducing agent in this exemplary embodiment mainly includes the following steps:

[0030] S1. Place acrylamide, N-vinylpyrrolidone, allyl imidazole and chain transfer agent in a container and stir until completely dissolved to obtain the first solution.

[0031] S2. Add an initiator to the first solution and react at 55-60°C for 6-8 hours to obtain the second solution.

[0032] S3. Add 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine to the second solution and react at 85-90℃ for 48-50 h. Then freeze and recrystallize the reaction product to obtain the filtrate loss reducer.

[0033] In this exemplary embodiment, in step S2, the reaction temperature of 55–60°C is chosen to account for the initiation temperature of the initiator. Below 55°C, the reaction is incomplete; above 60°C, the initiator decomposes too quickly, causing the reaction rate to rise sharply and the polymerization reaction to become uncontrolled. The present invention uses a reaction time of 6–8 hours to control the conversion rate. Less than 6 hours leads to incomplete monomer reaction; more than 8 hours allows the reaction to reach equilibrium, and the conversion rate of the generated product remains unchanged.

[0034] In this exemplary embodiment, the formulation components for preparing the quaternary ammonium salt type environmentally friendly high-temperature filtration loss reducing agent may include: by mass percentage, 25-30% acrylamide, 10-15% N-vinylpyrrolidone, 10-15% allyl imidazole, 15-20% 2-chloro-3-hydroxypropionic acid, 4-6% chain transfer agent, 0.2-0.4% initiator and 0.1-0.2% 4-dimethylaminopyridine.

[0035] Specifically, the raw materials and reagents used to prepare quaternary ammonium salt-type environmentally friendly high-temperature filtration loss reducing agents can be as follows:

[0036]

[0037] Anhydrous ethanol is used as the solvent for dissolution, and its composition is the remainder of the raw material reagents excluding the components in the above formula.

[0038] In this exemplary embodiment, the initiator may include any one of azobisisobutyrazoline hydrochloride (VO44), azobisisobutyramidine hydrochloride (V50), ammonium persulfate, potassium persulfate, and azobisisobutyronitrile (AIBN).

[0039] In this exemplary embodiment, the chain transfer agent may include any one of sodium formate, sodium hypophosphite, and sodium hypophosphite.

[0040] In this exemplary embodiment, step S2, the initiator addition reaction may include: cooling to room temperature after the reaction is completed.

[0041] In this exemplary embodiment, in step S3, the reaction of adding 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine to the second solution may include: cooling to room temperature after the reaction is completed, followed by freezing and recrystallization.

[0042] In this exemplary embodiment, the solvent used for dissolution in step S1 may include anhydrous ethanol.

[0043] In this exemplary embodiment, in step S2, the first solution is purged of air before the initiator is added. Here, an inert gas, such as N2, can be introduced into the solution to purge the air for 20-30 minutes. The purpose of introducing N2 is to remove air from the reaction solution; if air is present, it will consume the free radicals of the initiator, leading to incomplete reaction. The inert gas can also be helium, argon, etc.

[0044] In this exemplary embodiment, in step S3, 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine are added to the second solution to react, and the solution is purged of air for 20 to 30 minutes.

[0045] In this exemplary embodiment, the resulting quaternary ammonium salt-type environmentally friendly high-temperature filtration loss reducing agent may be a powdered filtration loss reducing agent.

[0046] Exemplary Example 2

[0047] This exemplary embodiment provides a quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer.

[0048] The quaternary ammonium salt type environmentally friendly high-temperature filtration loss reducing agent of this exemplary embodiment can be obtained by the preparation method of the quaternary ammonium salt type environmentally friendly high-temperature filtration loss reducing agent of Exemplary Embodiment 1 above.

[0049] In this exemplary embodiment, the structural formula of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer may include the following structural unit (I):

[0050]

[0051] To better understand the exemplary embodiments of the present invention described above, further explanation is provided below with reference to specific examples.

[0052] The preparation steps in Examples 1-7 below include:

[0053] Acrylamide, N-vinylpyrrolidone, allyl imidazole, and chain transfer agent (sodium formate) were prepared according to the raw material composition requirements of Examples 1-7. The raw materials were placed in a container to prepare a solution with a total monomer concentration of 50%. After complete dissolution, N2 was bubbled into the solution to purge air for 30 minutes. An initiator (AIBN) was then added to the solution, and the reaction was carried out at 60°C for 6 hours. After the reaction, the solution was cooled to room temperature for later use. 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine were added to the solution according to the corresponding raw material ratio, and N2 was bubbled into the solution to purge air for 30 minutes. The reaction was carried out at 90°C for 48 hours. After the reaction, the solution was cooled to room temperature and recrystallized to obtain a powdered filtration loss reducer. The filtration loss reducers in Examples 1-7 all possess the above-described structural unit (I).

[0054] Example 1

[0055] The raw materials and components used in this example preparation are shown in Table 1 below, resulting in a quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer L1.

[0056] Table 1. Main raw materials and components of filtration loss reducer L1

[0057]

[0058] Example 2

[0059] The raw materials and components used in this example preparation are shown in Table 2 below, resulting in a quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer L2.

[0060] Table 2 Main raw materials and components of filtration loss reducer L2

[0061]

[0062]

[0063] Example 3

[0064] The raw materials and components used in this example preparation are shown in Table 3 below, resulting in a quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer L3.

[0065] Table 3 Main raw materials and components of filtration loss reducer L3

[0066]

[0067] Example 4

[0068] The raw materials and components used in this example preparation are shown in Table 4 below, resulting in the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer L4.

[0069] Table 4. Main raw materials and components of filtration loss reducer L4

[0070]

[0071]

[0072] Example 5

[0073] The raw materials and components used in this example preparation are shown in Table 5 below, resulting in a quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer L5.

[0074] Table 5. Main raw materials and components of filter loss reducer L5

[0075]

[0076] Example 6

[0077] The raw materials and components used in this example preparation are shown in Table 6 below, resulting in the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer L6.

[0078] Table 6 Main raw materials and components of filtration loss reducer L6

[0079]

[0080]

[0081] Example 7

[0082] The raw materials and components used in this example preparation are shown in Table 7 below, resulting in a quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer L7.

[0083] Table 7 Main raw materials and components of filtration loss reducer L7

[0084]

[0085] Figure 1 The infrared spectrum of the filtration loss reducer L1 prepared in Example 1 is shown. The image shows the spectrum at 3400 cm⁻¹. -1 The peak at 2900 cm⁻¹ is a characteristic peak of the NH bond in allyl imidazole and acrylamide. -1 The signal peaks at 1670 cm⁻¹ are from the polymer backbone and the methyl and methylene groups in allyl imidazole; -1 The signal peak at 1500 cm⁻¹ is C=O. -1 The signal peak at 1450 cm⁻¹ is the CH signal peak on the benzene ring. -1 The signal peak at point N+ is 1045 cm⁻¹. -1 The signal peak at the position is -SO3; the infrared spectral data shows that the synthesized product has the target functional group unique to the monomer, and the target product was successfully obtained, that is, the filtration loss reducing agent obtained by the present invention is a filtration loss reducing agent with structural unit (I).

[0086] Figures 2-3 All images show the photoelectron spectra (XPS) of the filtration loss reducer L7 prepared in Example 7. As shown in the figures, the fine C(1s) spectrum exhibits signal peaks for C=O, CO, and CC at 288.62 eV, 287.19 eV, and 284.81 eV, respectively; the N(1s) spectrum shows signal peaks for CN and NH at 401.18 eV and 399.23 eV; and an N+ signal peak appears at 401.83 eV, mainly due to the quaternization reaction of the tertiary amine. The appearance of these signal peaks, combined with the FT-IR characterization results, demonstrates the successful preparation of the molecular structure of the quaternary ammonium salt-type environmentally friendly high-temperature filtration loss reducer designed in this invention.

[0087] The following are the biotoxicity test results of the filtration loss reducer L6 prepared in Example 6, which meet the environmental protection technical requirements for water-soluble oilfield chemicals.

[0088]

[0089] Comparative Example 1

[0090] The performance of the aforementioned quaternary ammonium salt-type environmentally friendly high-temperature filtration loss reducer L6 (hereinafter referred to as L6) in the base slurry was evaluated (filtration loss was measured), and its performance in the base slurry was compared with that of the three existing filtration loss reducers.

[0091] (1) Preparation of 4% bentonite-based slurry: Add 16g bentonite and 0.56g anhydrous sodium carbonate to 400mL water, stir at 8000r / min for 20 minutes, and let it stand at room temperature for 24h to hydrate.

[0092] (2) Preparation of base slurry sample: Take 400 mL of 4% bentonite base slurry, three portions, and add 8 g (2%) of L6 and three existing industrial filtration loss reducers respectively (filtration loss reducer 1 is drilling fluid filtration loss reducer polyanionic cellulose PAC-LV; filtration loss reducer 2 is high temperature water loss reducer modified natural resin product product code JNJS220; filtration loss reducer 3 is high temperature water loss reducer multi-component copolymer product code WNFB), and stir at 8000 r / min for 20 min.

[0093] (3) Sample aging treatment: Place the above samples in a roller heating furnace, set the aging temperature to 180℃, and the aging time to 16h.

[0094] The filtration loss of each sample was tested according to the determination method specified in GB / T16783.1-2014. Specific data can be found in [link to data]. Figure 4 .

[0095] from Figure 4 As can be seen, the filtration loss of the base slurry sample was 37 mL. The performance evaluation of filtration loss reducer 1 in the base slurry showed a filtration loss of 34 mL. The filtration loss of the sample containing filtration loss reducer 2 was 9.6 mL. The filtration loss of the sample containing filtration loss reducer 3 was 9.4 mL. The filtration loss of the sample containing L6 of this invention was only 4.8 mL, representing an 87% reduction compared to the base slurry with the highest filtration loss. Clearly, L6 can significantly improve the filtration loss of the base slurry sample and exhibits excellent filtration loss reduction ability after aging at 180℃ for 16 hours.

[0096] In summary, the advantages proposed by this invention include at least one of the following:

[0097] (1) The amide group (-NCO), carboxyl group (-COOH), and amine group (-NH) in the molecular structure (structure I) of the quaternary ammonium salt type environmentally friendly high temperature filtration loss reducer proposed in this invention are more easily biodegraded, thus improving the biodegradation activity.

[0098] (2) The preparation method of the quaternary ammonium salt type environmentally friendly anti-high temperature filtration loss agent proposed in this invention introduces quaternary ammonium salt cationic groups, which makes the polymer adsorption capacity strong and long-lasting at high temperature, playing a long-term stabilizing role, and has high compatibility with other anionic polymer treatment agents; in order to improve the hydration capacity of the polymer, hydroxyl and carboxyl groups are introduced to form a strong solvation layer on the clay surface, which enhances the polymer's temperature resistance and pollution resistance. The resulting quaternary ammonium salt type environmentally friendly anti-high temperature filtration loss agent has good high temperature resistance, and the temperature resistance can reach 180℃.

[0099] (3) The raw materials used in the preparation method of the quaternary ammonium salt type environmentally friendly high temperature filtration loss reducing agent proposed in this invention are available on the market, and the preparation method can be carried out using conventional equipment for preparing filtration loss reducing agents, which is relatively economical and applicable.

[0100] Although the present invention has been described above with reference to exemplary embodiments, including an environmentally friendly high-temperature filtration loss reducing agent and its preparation method, those skilled in the art should understand that various modifications and changes can be made to the exemplary embodiments of the present invention without departing from the spirit and scope defined by the claims.

Claims

1. A quaternary ammonium salt-type environmentally friendly high-temperature resistant filtration loss reducer, characterized in that, The structural formula of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer includes the following structural unit (I):

2. The quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 1, characterized in that, The formulation of the quaternary ammonium salt type environmentally friendly high-temperature filtration loss reducer includes: acrylamide, N-vinylpyrrolidone, allyl imidazole, 2-chloro-3-hydroxypropionic acid, chain transfer agent, initiator and 4-dimethylaminopyridine.

3. A method for preparing a quaternary ammonium salt-type environmentally friendly high-temperature filtration loss reducing agent as described in claim 1, characterized in that, The method includes: The first solution is obtained by mixing and dissolving acrylamide, N-vinylpyrrolidone, allyl imidazole and chain transfer agent; An initiator is added to the first solution to react, and the reaction is carried out at 55-60°C for 6-8 hours to obtain the second solution; 2-Chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine were added to the second solution and reacted at 85-90°C for 48-50 h. The mixture was then frozen and recrystallized to obtain the filtrate loss reducer.

4. The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 3, characterized in that, The material components in the method include, by mass percentage: 25-30% acrylamide, 10-15% N-vinylpyrrolidone, 10-15% allyl imidazole, 15-20% 2-chloro-3-hydroxypropionic acid, 4-6% chain transfer agent, 0.2-0.4% initiator, and 0.1-0.2% 4-dimethylaminopyridine.

5. The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 3, characterized in that, The initiator includes any one of azobisisobutyrazoline hydrochloride, azobisisobutyramidine hydrochloride, ammonium persulfate, potassium persulfate, and azobisisobutyronitrile.

6. The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 3, characterized in that, The chain transfer agent includes any one of sodium formate, sodium hypophosphite, and sodium hypophosphite.

7. The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 3, characterized in that, The initiator addition reaction includes: cooling to room temperature after the reaction is completed; the addition of 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine to the second solution includes: cooling to room temperature after the reaction is completed.

8. The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 3, characterized in that, The solvent used for the dissolution includes anhydrous ethanol.

9. The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 3, characterized in that, After dissolution, the air in the first solution is purged before adding the initiator; when adding 2-chloro-3-hydroxypropionic acid and 4-dimethylaminopyridine to the second solution for reaction, the air in the current solution is purged.

10. The preparation method of the quaternary ammonium salt type environmentally friendly high-temperature resistant filtration loss reducer according to claim 9, characterized in that, The air purging process includes: introducing inert gas to purge air for 20 to 30 minutes.

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