Clay stabilizers and methods for making the same

Abstract

The application discloses a clay stabilizer and a preparation method thereof, and belongs to the technical field of oil field additives, and comprises the following steps: dissolving a first monomer and 2,3-epoxypropyl trimethyl ammonium chloride in a solvent, or respectively dissolving the first monomer and 2,3-epoxypropyl trimethyl ammonium chloride in a solvent to configure a solution, then dropping the 2,3-epoxypropyl trimethyl ammonium chloride solution into the first monomer solution; then, reaction is carried out to obtain a reaction liquid; after the reaction is completed, the reaction liquid is separated and purified to obtain the clay stabilizer; the first monomer is an aromatic diamine, the aromatic diamine is p-phenylenediamine, o-phenylenediamine or m-phenylenediamine, the number of active hydrogens on an amine group in the first monomer is n, and the molar ratio of the first monomer to the 2,3-epoxypropyl trimethyl ammonium chloride is 1:0.9n-1.1n. The clay stabilizer has good shale inhibition effect, and the preparation method is simple and easy to popularize.

Description

[0001] This application is a divisional application of Chinese invention patent application filed on September 14, 2024, with application number 202411289649.X and invention title "Clay Stabilizer and Preparation Method Thereof". Technical Field

[0002] This invention belongs to the field of oilfield additives technology, specifically relating to a clay stabilizer and its preparation method. Background Technology

[0003] Clay minerals mainly include several categories such as montmorillonite, kaolinite, illite, chlorite, illite-montmorillonite mixed layers, and chlorite-montmorillonite mixed layers. Clay minerals are widely present in oil and gas reservoirs. During oilfield exploration and development, such as drilling, well completion, acidizing, fracturing, and water injection, these clay mineral particles will expand or migrate when encountering external water-based fluids, thus clogging pores or fracture media and affecting permeability and oil and gas well production. Generally, to protect the permeability of oil and gas reservoirs and improve oil and gas production, during fracturing, acidizing, or well workover operations, inhibitory clay stabilizers are used to mitigate clay expansion or migration in shale or clay-type formations.

[0004] Amine clay stabilizers are a commonly used type of clay stabilizer. They primarily utilize the cationic nature of the amino groups, allowing them to adsorb onto the clay surface and neutralize the surface charge. Another component consists of hydrophobic groups, which prevent water molecules from further approaching the clay. Therefore, amine clay stabilizers are characterized by low dosage and high effectiveness. However, current polyamine clay stabilizers require more raw materials and involve more complex preparation processes, resulting in higher costs and limited application in actual production. Summary of the Invention

[0005] The purpose of this invention is to provide a clay stabilizer and its preparation method. The clay stabilizer has a good shale inhibition effect, and its preparation method is simple and easy to promote.

[0006] To achieve the above-mentioned objectives, the following technical solution is adopted:

[0007] A method for preparing a clay stabilizer includes the following steps: dissolving a first monomer and 2,3-epoxypropyltrimethylammonium chloride in a solvent, or dissolving the first monomer and 2,3-epoxypropyltrimethylammonium chloride separately in a solvent to prepare solutions, and then adding the 2,3-epoxypropyltrimethylammonium chloride solution dropwise to the first monomer solution; then reacting to obtain a reaction solution; after the reaction is completed, separating and purifying the reaction solution to obtain the clay stabilizer; wherein, the first monomer is an aliphatic compound containing at least one primary amine or an aromatic compound containing at least one primary amine, the number of active hydrogens on the amine group in the first monomer is n, and the molar ratio of the first monomer to the 2,3-epoxypropyltrimethylammonium chloride is 1:0.9n~1.1n.

[0008] Specifically, in this invention, the primary method involves reacting the amino group containing active hydrogen in the first monomer with the epoxy group in 2,3-epoxypropyltrimethylammonium chloride to generate a tertiary amine and an alcohol. The active hydrogen on the amino group referred to in this invention is hydrogen directly bonded to a nitrogen atom; for example, a primary amine has two active hydrogens, and a secondary amine has one. Simultaneously, 1 mole of the primary amine can react with 2 moles of the epoxy group. Therefore, after complete reaction, the synthesized clay stabilizer molecule contains two quaternary ammonium groups and two tertiary amine groups. These groups greatly increase the inhibitory performance of the clay stabilizer. Furthermore, after the reaction, it also contains at least two hydroxyl groups, which can also adsorb onto the clay, further enhancing its inhibitory effect. For example, the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride can also be 1:0.95n~1.05n.

[0009] The aliphatic compound containing at least one primary amine is an aliphatic mono-primary amine, a polyethylene polyamine, an aliphatic diamine, or an aliphatic compound containing one primary amine and one tertiary amine. The aromatic compound containing at least one primary amine is an aromatic mono-primary amine, an aromatic diamine, or an aromatic compound containing one primary amine and one tertiary amine.

[0010] The aliphatic compound containing one primary amine and one tertiary amine is one of N,N-dibutyl-1,3-propanediamine, N,N-diethylethylenediamine, and N,N-dimethylethylenediamine, and the aromatic compound containing one primary amine and one tertiary amine is one of N,N-dimethyl-1,4-phenylenediamine and N1,N1-dimethyl-1-phenylethane-1,2-diamine.

[0011] The aliphatic monoamine is one of n-pentylamine and n-hexylamine; the aromatic monoamine is one of aniline, p-aminotoluene, and phenethylamine; the polyethylene polyamine is diethylenetriamine or triethylenetetramine; the aromatic diamine is p-phenylenediamine; and the aliphatic diamine is hexamethylenediamine.

[0012] In this field, there are many organic compounds containing a primary amine monomer, such as the more common aliphatic primary amines and aromatic primary amines. Based on the number of amine groups, they can be further subdivided into aliphatic mono-primary amines, aromatic mono-primary amines, polyethylene polyamines, aliphatic diamines, aromatic diamines, and other amines containing heteroatoms. Theoretically, all of these compounds can be used in this invention.

[0013] However, after extensive experimentation, the inventors discovered that aliphatic and aromatic primary amines exhibit better performance than other amines, particularly n-pentylamine, n-hexylamine, aniline, p-aminotoluene, and phenethylamine. Among aliphatic primary amines, both excessively short and excessively long carbon chain lengths result in poor clay stabilizer performance: short carbon chains lead to poor hydrophobicity, while excessively long carbon chains weaken the amine group's activity. Therefore, in this invention, n-pentylamine and n-hexylamine are typically chosen for aliphatic primary amines. For aromatic primary amines, the presence of the benzene ring enhances their hydrophobicity; however, excessively large molecular weights can lead to overly strong hydrophobicity, thus reducing the effectiveness of the clay stabilizer. Therefore, after extensive experimentation, the inventors selected aniline, p-aminotoluene, and phenethylamine, which have lower molecular weights, as they exhibit better performance.

[0014] For polyethylene polyamines (such as diethylenetriamine and triethylenetetramine), aliphatic diamines (such as hexamethylenediamine), and aromatic diamines (such as phenylenediamine, which is divided into o-phenylenediamine, m-phenylenediamine, and p-phenylenediamine), due to the presence of multiple active hydrogen atoms, the resulting clay stabilizers are too hydrophilic. Although they have a certain clay stabilizing effect, in practice, their effect is relatively poor.

[0015] In particular, the inventors discovered a special class of first monomers during their experiments: aliphatic or aromatic compounds containing one primary amine and one tertiary amine. When using this type of compound as the first monomer, its effect is better than that of aliphatic and aromatic mono-primary amines. There are many compounds of this type, such as N,N-dimethyl-1,4-phenylenediamine, N'-benzyl-N,N-dimethylethylenediamine, N1,N1-dimethyl-1-phenylethane-1,2-diamine, N,N-dibutyl-1,3-propanediamine, N,N-diethylethylenediamine, and N,N-dimethylethylenediamine (there are two types of amines with this name; here it refers to an amine compound containing one primary amine and one tertiary amine), etc. These are all relatively mature products and are available on the market.

[0016] During the reaction, the solvent used needs to completely dissolve both the first monomer and 2,3-epoxypropyltrimethylammonium chloride. Therefore, one of ethanol, isopropanol, acetone, toluene, or dimethyl sulfoxide can be chosen as the solvent. Of course, those skilled in the art can also choose other solvents. Furthermore, the reaction of this invention is carried out at 20-70°C for 1-8 hours, which are relatively mild conditions, allowing the reaction to occur at room temperature. After extensive experimentation, the inventors found that when the temperature exceeds 70°C, not only is the reaction difficult to control, but side reactions are also prone to occur, leading to reduced yield and poorer results. Conversely, when the temperature is below 20°C, the reaction rate is slow, making large-scale application difficult.

[0017] Meanwhile, during the reaction, the two can be directly mixed and reacted, or the first monomer and 2,3-epoxypropyltrimethylammonium chloride can be prepared into solutions separately, and then the 2,3-epoxypropyltrimethylammonium chloride solution can be added dropwise to the first monomer solution to carry out the reaction. From the perspective of efficiency, the latter method is better, but it takes more time. Those skilled in the art can choose the appropriate method according to the actual situation.

[0018] One embodiment of the present invention involves the following specific steps for separation and purification: Under continuous stirring, diethyl ether or petroleum ether is added to the reaction solution. After stirring, the mixture is allowed to stand for crystallization. The crystalline precipitate is then collected and dried to obtain the clay stabilizer. During the addition of diethyl ether or petroleum ether, continuous stirring is maintained. As the amount of diethyl ether or petroleum ether increases, crystals gradually precipitate. After stirring, the mixture is allowed to stand for a period of time and then filtered to obtain the crystalline precipitate. In this step, the amount of diethyl ether or petroleum ether added is typically more than 5 times, and usually 10 times, the total volume of the reaction solution. In addition to the above separation and purification method, the following method can also be used for separation and purification: The solvent in the reaction solution is removed by vacuum distillation to obtain a solid phase. The solid phase is washed several times with diethyl ether or petroleum ether, and then dried to obtain the clay stabilizer. Those skilled in the art can choose one of these methods according to the actual situation, or other methods can be used for separation and purification.

[0019] One embodiment of the present invention is that the reaction is carried out under alkaline conditions. While the reaction conditions are typically alkaline, since some of the raw materials are already alkaline, the reaction can proceed without the addition of an external alkali. If the pH of the reaction solution is less than 7, it can be adjusted by adding an alkali, typically an inorganic alkali such as sodium hydroxide or potassium hydroxide.

[0020] A clay stabilizer is disclosed, which is prepared using any of the above-described methods for preparing clay stabilizers. The clay stabilizer prepared by the method of the present invention exhibits high inhibition performance and can be applied to oil and gas development processes such as drilling and fracturing.

[0021] Compared with the prior art, the present invention has the following beneficial technical effects:

[0022] The clay stabilizer prepared by the method of the present invention has good shale stability performance. The preparation method is simple, requiring only one reaction step, and the reaction conditions are mild. At the same time, the raw materials are low in cost and easy to obtain, making it suitable for large-scale promotion. In addition, its viscosity is low, which can be applied to some low viscosity environments, thus expanding its application range. Detailed Implementation

[0023] All features disclosed in this specification, or steps in all methods or processes disclosed, may be combined in any way except for mutually exclusive features and / or steps, and may be replaced by other equivalent or similar alternative features unless specifically stated otherwise. That is, unless specifically stated otherwise, each feature is only one embodiment of a series of equivalent or similar features.

[0024] The clay stabilizer and its preparation method of the present invention will be further illustrated below with reference to the embodiments.

[0025] Unless otherwise specified, the experimental methods used in all the following examples are conventional methods.

[0026] Unless otherwise specified, all materials and reagents used in the following examples are commercially available.

[0027] In all the following examples, the percentage of clay stabilizer added is by mass.

[0028] In all the following embodiments, the rolling recovery rate and dynamic viscosity of the clay stabilizer prepared by the method of the present invention were measured using the method disclosed in SY / T6335-1997 "Evaluation Method for Shale Inhibitors for Drilling Fluids". It should be noted that in all the following embodiments, according to SY / T6335-1997 "Evaluation Method for Shale Inhibitors for Drilling Fluids", the mass percentage of clay stabilizer added in the corresponding embodiments was calculated based on the amount of water added.

[0029] Example 1

[0030] In this embodiment, the first monomer is N,N-dimethyl-1,4-phenylenediamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:2.1. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0031] 13.6 g of N,N-dimethyl-1,4-phenylenediamine and 31.8 g of 2,3-epoxypropyltrimethylammonium chloride were dissolved in isopropanol. Then, the 2,3-epoxypropyltrimethylammonium chloride solution was added dropwise to the N,N-dimethyl-1,4-phenylenediamine solution. The reaction was carried out at 30°C for 4 hours to obtain a reaction solution. After the reaction was completed, approximately 10 times the volume of the reaction solution was added to the reaction solution under continuous stirring. After stirring, the solution was allowed to stand for crystallization for 10 minutes, filtered, and the resulting crystalline precipitate was dried to obtain the clay stabilizer. In this example, isopropanol was used as the solvent.

[0032] Tests showed that when the amount of clay stabilizer obtained in this embodiment was 0.3%, its rolling recovery rate at 120°C was 87.8%; and when the amount of clay stabilizer obtained in this embodiment was 1% added to water, its dynamic viscosity at 20°C was 1.25 mPa·s.

[0033] Example 2

[0034] In this embodiment, the first monomer is N1,N1-dimethyl-1-phenylethane-1,2-diamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:1.9. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0035] 16.4 g of N1,N1-dimethyl-1-phenylethane-1,2-diamine and 28.8 g of 2,3-epoxypropyltrimethylammonium chloride were added to ethanol and dissolved. The mixture was reacted at 40°C for 3 hours to obtain a reaction solution. After the reaction was completed, approximately 10 times the volume of the reaction solution was added to the reaction solution under continuous stirring. After stirring, the mixture was allowed to stand for crystallization for 10 minutes, filtered, and the resulting crystalline precipitate was dried to obtain the clay stabilizer. In this example, ethanol was used as the solvent.

[0036] Tests showed that when the amount of clay stabilizer obtained in this embodiment was 0.3%, its rolling recovery rate at 120°C was 85.4%; and when the amount of clay stabilizer obtained in this embodiment was 1% added to water, its dynamic viscosity at 20°C was 1.30 mPa·s.

[0037] Example 3

[0038] In this embodiment, the first monomer is N,N-dibutyl-1,3-propanediamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:2.0. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0039] 18.6 g of N,N-dibutyl-1,3-propanediamine and 30.3 g of 2,3-epoxypropyltrimethylammonium chloride were added to ethanol and dissolved. The mixture was reacted at 20°C for 2 hours to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this embodiment, "several times" can refer to two, three, four, or more washes. The specific number of washes is determined by thoroughly cleaning the solvent from the solid phase. The meaning of "several times" in all subsequent embodiments is the same as that in this embodiment and will not be repeated hereafter. In this embodiment, ethanol is used as the solvent.

[0040] Tests showed that when the clay stabilizer obtained in this embodiment was added at a dosage of 0.3%, its rolling recovery rate at 120°C was 86.1%; and when the clay stabilizer obtained in this embodiment was added to water at a dosage of 1%, its dynamic viscosity at 20°C was 1.67 mPa·s.

[0041] Example 4

[0042] In this embodiment, the first monomer is N,N-diethylethylenediamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:2.1. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0043] 11.6 g of N,N-diethylethylenediamine and 31.8 g of 2,3-epoxypropyltrimethylammonium chloride were added to ethanol and dissolved. The mixture was reacted at 40 °C for 1 h to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this example, ethanol was used as the solvent.

[0044] Tests showed that when the amount of clay stabilizer obtained in this embodiment was 0.3%, its rolling recovery rate at 120°C was 83.4%; and when the amount of clay stabilizer obtained in this embodiment was 1% added to water, its dynamic viscosity at 20°C was 1.95 mPa·s.

[0045] Example 5

[0046] In this embodiment, the first monomer is n-pentylamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:2.0. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0047] 8.7 g of n-pentylamine and 30.3 g of 2,3-epoxypropyltrimethylammonium chloride were added to ethanol and dissolved. The mixture was reacted at 20 °C for 2 h to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this example, ethanol was used as the solvent.

[0048] Tests showed that when the amount of clay stabilizer obtained in this embodiment was 0.3%, its rolling recovery rate at 120°C was 82.1%; and when the amount of clay stabilizer obtained in this embodiment was 1% added to water, its dynamic viscosity at 20°C was 1.74 mPa·s.

[0049] Example 6

[0050] In this embodiment, the first monomer is propylamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:2.0. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0051] 5.9 g of propylamine and 30.3 g of 2,3-epoxypropyltrimethylammonium chloride were added to ethanol and dissolved. The mixture was reacted at 30 °C for 1 h to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this example, ethanol was used as the solvent.

[0052] Tests showed that when the clay stabilizer obtained in this embodiment was added at a dosage of 0.3%, its rolling recovery rate at 120°C was 71.2%; and when the clay stabilizer obtained in this embodiment was added to water at a dosage of 1%, its dynamic viscosity at 20°C was 1.44 mPa·s.

[0053] Example 7

[0054] In this embodiment, the first monomer is n-octylamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:2.0. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0055] 12.9 g of n-octylamine and 30.3 g of 2,3-epoxypropyltrimethylammonium chloride were added to ethanol and dissolved. The mixture was reacted at 30 °C for 4 h to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this example, ethanol was used as the solvent.

[0056] Tests showed that when the clay stabilizer obtained in this embodiment was added at a dosage of 0.3%, its rolling recovery rate at 120°C was 68.7%; and when the clay stabilizer obtained in this embodiment was added to water at a dosage of 1%, its dynamic viscosity at 20°C was 1.72 mPa·s.

[0057] Example 8

[0058] In this embodiment, the first monomer is phenethylamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:2.0. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0059] 12.1 g of phenethylamine and 30.3 g of 2,3-epoxypropyltrimethylammonium chloride were added to acetone and dissolved. The mixture was reacted at 70 °C for 3 h to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this example, acetone was used as the solvent.

[0060] Tests showed that when the amount of clay stabilizer obtained in this embodiment was 0.3%, its rolling recovery rate at 120°C was 85.5%; and when the amount of clay stabilizer obtained in this embodiment was 1% added to water, its dynamic viscosity at 20°C was 1.53 mPa·s.

[0061] Example 9

[0062] In this embodiment, the first monomer is p-phenylenediamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:4.1. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0063] 10.8 g of p-phenylenediamine and 62.2 g of 2,3-epoxypropyltrimethylammonium chloride were added to acetone and dissolved. The mixture was reacted at 40 °C for 8 h to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this example, acetone was used as the solvent.

[0064] Tests showed that when the amount of clay stabilizer obtained in this embodiment was 0.3%, its rolling recovery rate at 120°C was 72.0%; and when the amount of clay stabilizer obtained in this embodiment was 1% added to water, its dynamic viscosity at 20°C was 2.42 mPa·s.

[0065] Example 10

[0066] In this embodiment, the first monomer is diethylenetriamine, and the molar ratio of the first monomer to 2,3-epoxypropyltrimethylammonium chloride is 1:4.8. The preparation method of the clay stabilizer in this embodiment includes the following steps:

[0067] 10.3 g of diethylenetriamine and 73.3 g of 2,3-epoxypropyltrimethylammonium chloride were added to acetone and dissolved. The mixture was reacted at 40 °C for 3 h to obtain a reaction solution. After the reaction was completed, the solvent in the reaction solution was removed by vacuum distillation to obtain a solid phase. The solid phase was then washed several times with diethyl ether and dried to obtain the clay stabilizer. In this example, acetone was used as the solvent.

[0068] Tests showed that when the clay stabilizer obtained in this embodiment was added at a dosage of 0.3%, its rolling recovery rate at 120°C was 80.9%; and when the clay stabilizer obtained in this embodiment was added to water at a dosage of 1%, its dynamic viscosity at 20°C was 5.77 mPa·s.

[0069] Example 11

[0070] The difference between this embodiment and Embodiment 1 is that the reaction temperature is 80°C, while all other aspects are the same.

[0071] Tests showed that when the amount of clay stabilizer obtained in this embodiment was 0.3%, its rolling recovery rate at 120°C was 57.2%; and when the amount of clay stabilizer obtained in this embodiment was 1% added to water, its dynamic viscosity at 20°C was 5.19 mPa·s.

[0072] In the aforementioned Examples 1 to 11, the reaction conditions are usually alkaline. However, since some raw materials are usually alkaline, the reaction can be carried out without the addition of an external alkali. If the pH of the reaction solution is less than 7, it can be adjusted by adding an alkali. The alkali added can usually be an inorganic alkali such as sodium hydroxide or potassium hydroxide.

[0073] The experimental data on the rolling recovery rate and dynamic viscosity of the clay stabilizer obtained from the tests in Examples 1 to 11 above show that: the clay stabilizer prepared by the method of the present invention has good shale stability performance; the preparation method of the clay stabilizer of the present invention is simple, requiring only one reaction step, and the reaction conditions are mild. At the same time, the cost of the raw materials is low and the raw materials are easy to obtain, making it suitable for large-scale promotion; in addition, the clay stabilizer prepared by the method of the present invention has low viscosity, which can be applied to some low viscosity environments, thus expanding its application range.

Claims

1. A method for preparing a clay stabilizer, characterized by, The method comprises the following steps: dissolving a first monomer and 2,3-epoxypropyltrimethylammonium chloride in a solvent, or respectively dissolving the first monomer and 2,3-epoxypropyltrimethylammonium chloride in a solvent to prepare a solution, and then adding the 2,3-epoxypropyltrimethylammonium chloride solution into the first monomer solution; then, performing a reaction to obtain a reaction liquid; after the reaction is completed, the reaction liquid is separated and purified to obtain the clay stabilizer; wherein the first monomer is an aromatic diamine, the aromatic diamine is p-phenylenediamine, o-phenylenediamine or m-phenylenediamine; the number of active hydrogen on the amine group in the first monomer is n, and the molar ratio of the first monomer to the 2,3-epoxypropyltrimethylammonium chloride is 1:0.9n-1.1n.

2. The method of claim 1, wherein the clay stabilizer is prepared by the steps of: The solvent is one of ethanol, isopropyl alcohol, acetone, toluene and dimethyl sulfoxide.

3. The method for preparing the clay stabilizer according to claim 1, characterized in that, The specific operation of the separation and purification is: under the condition of continuous stirring, adding diethyl ether or petroleum ether into the reaction liquid, after stirring is completed, crystallization is carried out, the crystallization precipitate is taken out, and then the taken crystallization precipitate is dried to obtain the clay stabilizer; or the specific operation of the separation and purification is: removing the solvent in the reaction liquid by distillation under reduced pressure to obtain a solid phase, washing the solid phase several times with diethyl ether or petroleum ether, and then drying the washed solid phase to obtain the clay stabilizer.

4. The method of claim 1, wherein the clay stabilizer is prepared by the steps of: The reaction is performed under the condition of 20-70 DEG C, and the reaction time is 1-8 hours.

5. The method for preparing the clay stabilizer according to claim 1, characterized in that, The reaction is performed under alkaline conditions.

6. A clay stabilizer characterized by, The clay stabilizer is prepared by the method of any one of claims 1-5.