Preparation method of clay stabilizer, clay stabilizer and application

Abstract

The application relates to the technical field of oil production engineering, and particularly discloses a preparation method of a clay stabilizer, the clay stabilizer and application; the preparation method of the clay stabilizer comprises the following steps: under a nitrogen environment, ethylenediamine tetraethanol, polyethylene amine and a supported amine catalyst are added into a reactor, the molar ratio of the ethylenediamine tetraethanol and the polyethylene amine is 1:(6-8.3); then hydrogen is introduced, stirring is started, and the reaction is carried out at a temperature of 200-240 DEG C for 3-6 hours; and after the reaction is completed, the clay stabilizer is separated. The preparation process of the clay stabilizer is simple, the clay stabilizer contains multiple amine groups, the adsorption points are many, and the anti-swelling effect of the clay stabilizer can be effectively improved.

Description

Technical Field

[0001] This application relates to the field of oilfield engineering technology, and more specifically, to a method for preparing a clay stabilizer, the clay stabilizer itself, and its application. Background Technology

[0002] Clay minerals are widely present in oil reservoirs; 97% of the world's oil reservoirs contain clay minerals to varying degrees. When these clays come into contact with water or water-based substances during water injection, acidizing, and fracturing, they swell and disperse into fine particles with a diameter of less than 10 μm. This clogs the throats of the formation's pore structure, reduces formation permeability, and causes formation damage. Therefore, for reservoirs with high clay content and strong water sensitivity, clay stabilizers are generally used during drilling, cementing, water injection, fracturing, acidizing, well workover, and well control operations to prevent clay expansion from affecting formation permeability.

[0003] Currently, commonly used anti-swelling agents mainly include inorganic salts, cationic polymers, and quaternary ammonium salts. Inorganic salts, as the earliest clay anti-swelling agents, primarily utilize inorganic salt ions such as K+ to embed into the clay crystal structure to neutralize the clay's electronegativity. However, inorganic salt-based clay anti-swelling agents have weak binding force with the formation and poor ability to prevent clay migration. Cationic polymers contain multiple positive charges in their molecules, allowing for multi-point adsorption on the clay mineral surface, resulting in good anti-swelling effects and erosion resistance. However, their large molecular weight easily clogs formation pores and throats, impairing formation permeability, making them unsuitable for dense formations. Furthermore, cationic polymers have poor temperature resistance, easily decomposing at high temperatures, causing their anti-swelling effect to disappear. Although quaternary ammonium salts have small molecular weights and do not clog the formation themselves, their anti-swelling effect is inferior to that of cationic polymers because they can only produce single-point adsorption on the clay surface.

[0004] CN105198757B discloses a small cationic bisquaternary ammonium salt clay stabilizer and its preparation method. Using epichlorohydrin, small molecule tertiary amine and hydrochloric acid as raw materials, a clay anti-swelling agent with relatively high charge density is prepared. However, due to the still relatively small number of adsorption sites on the clay surface, its anti-swelling effect is not ideal.

[0005] CN115232016B discloses a clay stabilizer solution and its preparation method. This clay stabilizer is prepared by a tertiary amination reaction of dimethylamine and benzyl chloride to obtain an N,N-dimethylaniline intermediate, followed by a quaternization reaction with glycidyltrimethylammonium chloride. This clay stabilizer has two N+ ions, allowing it to simultaneously adsorb clay and exhibit a certain anti-swelling effect. However, due to the limited number of adsorption sites on the clay surface, its anti-swelling effect is not ideal. Furthermore, existing clay stabilizers generally suffer from complex preparation processes.

[0006] Therefore, there is a need to develop a clay stabilizer that has a simple preparation process, multiple adsorption sites, strong binding force with the formation, and good anti-swelling properties. Summary of the Invention

[0007] This application provides a method for preparing a clay stabilizer, as well as the clay stabilizer and its application. The prepared clay stabilizer has multiple amine groups in its molecular structure and many adsorption sites, which can effectively improve the anti-swelling effect of the clay stabilizer. Moreover, the method for preparing the clay stabilizer obtained in this application is simple.

[0008] In a first aspect, this application provides a method for preparing a clay stabilizer, employing the following technical solution:

[0009] A method for preparing a clay stabilizer includes the following steps:

[0010] In a nitrogen atmosphere, ethylenediaminetetraethanol, polyethyleneamine, and a supported amination catalyst are added to a reactor, wherein the molar ratio of ethylenediaminetetraethanol to polyethyleneamine is 1:(6-8.3); then hydrogen is introduced, stirring is started, and the reaction is carried out at a temperature of 200-240℃ for 3-6 hours. After the reaction is completed, the clay stabilizer is separated.

[0011] Furthermore, the polyethyleneamine is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0012] Furthermore, the supported amination catalyst is composed of a main active component, an auxiliary agent, and a support. The main active component is a mixture of Ni, Cu, and Re; the auxiliary agent is one or more of Cr, Fe, or Zn; and the support is a molecular sieve or alumina.

[0013] Furthermore, in the main active component, the Ni loading is 15-30% of the weight of the supported amination catalyst, the Cu loading is 5-10% of the weight of the supported amination catalyst, and the Re loading is 5-10% of the weight of the supported amination catalyst.

[0014] Furthermore, in the additive, the loading of Cr is 0.5-2% of the weight of the supported amination catalyst, the loading of Fe is 1-2.5% of the weight of the supported amination catalyst, and the loading of Zn is 0.5-2.5% of the weight of the supported amination catalyst.

[0015] Furthermore, the particle size of the supported amination catalyst is 0.1–5 mm.

[0016] Furthermore, the amount of the supported amination catalyst added is 5-10% of the total mass of ethylenediaminetetraethanol and ethyleneamine.

[0017] Further, nitrogen gas is introduced into the magnetic high-pressure reactor for airtightness testing; then ethylenediaminetetraethanol, ethyleneamine, and supported amination catalyst are added to the magnetic high-pressure reactor, and the reactor is tightened; the magnetic high-pressure reactor is purged with nitrogen gas; then purged again with hydrogen gas; finally, hydrogen gas is introduced into the reactor.

[0018] Furthermore, during the reaction, the initial partial pressure of hydrogen is 1.5–3.0 MPa.

[0019] Secondly, this application provides a clay stabilizer, which adopts the following technical solution:

[0020] A clay stabilizer comprising a substance with the structure shown in formula (1):

[0021]

[0022] Where n is any integer from 0 to 4.

[0023] Thirdly, this application provides an application of a clay stabilizer, employing the following technical solution:

[0024] An application of a clay stabilizer, wherein the clay stabilizer is used in oilfield oil production technology.

[0025] In summary, this application has the following beneficial effects:

[0026] (1) The clay stabilizer of this application introduces multiple amine groups into its molecular structure, which can form amine cations in aqueous solution. When used, it can neutralize the negative charge on the clay surface and reduce the Zeta sites of clay particles, and can also enhance the adhesion of the stratum through electrostatic adsorption, thereby greatly improving the anti-swelling performance and water washability of the clay stabilizer. When its addition amount is only 0.1%, it can achieve an anti-swelling rate of more than 87% and a water washability of more than 97%.

[0027] (2) The clay stabilizer is prepared by one-step reaction in this application. The process is simple and easy to industrialize. No organic solvents are used, resulting in less waste and environmental protection. Detailed Implementation

[0028] The present application will be further described in detail below with reference to the embodiments.

[0029] Example

[0030] The embodiments of this application first provide a method for preparing a clay stabilizer, including the following steps:

[0031] Under nitrogen atmosphere, ethylenediaminetetraethanol, polyethyleneamine, and a supported amination catalyst are added to a reactor, followed by hydrogen gas introduction and stirring. The reaction is carried out at 200-240°C for 3-6 hours. After the reaction, the clay stabilizer is obtained. The molar ratio of ethylenediaminetetraethanol to polyethyleneamine is 1:(6-8.3). The amount of supported amination catalyst added is 5-10% of the total mass of ethylenediaminetetraethanol and polyethyleneamine.

[0032] Furthermore, the polyethyleneamine is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

[0033] Further, the supported amination catalyst consists of a main active component, an auxiliary agent, and a support. The main active component is a mixture of Ni, Cu, and Re; the auxiliary agent is one or more of Cr, Fe, or Zn; and the support is a molecular sieve or alumina. Specifically, in the main active component, the Ni loading is 15-30% of the weight of the supported amination catalyst, the Cu loading is 5-10% of the weight of the supported amination catalyst, and the Re loading is 5-10% of the weight of the supported amination catalyst. In the auxiliary agent, the Cr loading is 0.5-2% of the weight of the supported amination catalyst, the Fe loading is 1-2.5% of the weight of the supported amination catalyst, and the Zn loading is 0.5-2.5% of the weight of the supported amination catalyst. The particle size of the supported amination catalyst is 0.1-5 mm. The supported amination catalyst in the embodiments of this application can be prepared using conventional preparation methods.

[0034] Specifically, it includes the following steps:

[0035] (1) Fill the magnetic high-pressure reactor with 6.0 MPa of nitrogen gas and check the airtightness.

[0036] (2) Add ethylenediaminetetraethanol, ethyleneamine and supported amination catalyst to a magnetic high-pressure reactor and tighten the reactor.

[0037] (3) Replace the magnetic high-pressure reactor three times with nitrogen gas at 0.5 MPa; then replace it twice more with hydrogen gas at 0.5 MPa.

[0038] (4) Introduce hydrogen gas at a certain pressure into the magnetic high-pressure reactor; the initial partial pressure of hydrogen gas is 1.5 to 3.0 MPa;

[0039] (5) Turn on the stirring and gradually raise the temperature to the required reaction temperature, and carry out the reaction at the reaction temperature;

[0040] (6) After the reaction is complete, cool to room temperature, release pressure and discharge the material. Separate the catalyst and product by filtration. The product is the clay stabilizer.

[0041] The clay stabilizer prepared above includes substances with the structure shown in formula (1):

[0042]

[0043] Where n is any integer from 0 to 4. The values ​​of n on each branch are independent of each other.

[0044] The aforementioned clay stabilizers are applied to oilfield oil production technology.

[0045] The following explanation is provided through specific examples.

[0046] Example 1

[0047] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 4.

[0048] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0049] Raw material preparation:

[0050] Weigh out 22.8g of ethylenediaminetetraethanol, 185.6g of pentaethylenehexamine and 18.765g of supported amination catalyst.

[0051] In the supported amination catalyst, the support is alumina with a particle size of 0.5 mm; the active components and additives supported in the catalyst are as follows: 30% Ni, 6% Cu, 10% Re, 1.8% Cr, 2.5% Fe, and 1.5% Zn.

[0052] Preparation process:

[0053] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the leak was found to be airtight, the reactor was opened, raw materials were added, and the reactor was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 2 MPa, and the reactor was slowly heated to 220°C under stirring. The reaction was allowed to proceed for 6 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S1.

[0054] Example 2

[0055] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 3.

[0056] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0057] Raw material preparation:

[0058] Weigh out 22.8g of ethylenediaminetetraethanol, 122.85g of tetraethylenepentamine and 11.652g of supported amination catalyst.

[0059] The supported amination catalyst has an alumina support with a particle size of 1 mm. The active components and additives supported in the catalyst are as follows: 28% Ni, 7% Cu, 8% Re, 2% Cr, 2% Fe, and 1% Zn.

[0060] Preparation process:

[0061] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the airtightness was good, the reactor was opened, raw materials were added, and the mixture was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 1.5 MPa, and the mixture was stirred and slowly heated to 230°C for 3.5 hours. After the reaction, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S2.

[0062] Example 3

[0063] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 1.

[0064] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0065] Raw material preparation:

[0066] Weigh out 22.8g of ethylenediaminetetraethanol, 82.4g of diethylenetriamine and 10.52g of supported amination catalyst.

[0067] The supported amination catalyst has an alumina support with a particle size of 4 mm. The active components and additives supported in the catalyst are as follows: 30% Ni, 9% Cu, 10% Re, 1.5% Cr, 1.5% Fe, and 2% Zn.

[0068] Preparation process:

[0069] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the leak was found to be airtight, the reactor was opened, raw materials were added, and the reactor was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas at 2.5 MPa was then introduced, and the reactor was slowly heated to 240°C under stirring. The reaction was allowed to proceed for 5.5 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S3.

[0070] Example 4

[0071] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 2.

[0072] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0073] Raw material preparation:

[0074] Weigh out 22.8g of ethylenediaminetetraethanol, 109.5g of triethylenetetramine and 13.23g of supported amination catalyst.

[0075] The supported amination catalyst has an alumina support with a particle size of 3.5 mm. The active components and additives supported in the catalyst are as follows: 29% Ni, 11% Cu, 6% Re, 1% Cr, 1.5% Fe, and 2.5% Zn.

[0076] Preparation process:

[0077] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and the reactor was checked for leaks using foam water. The reactor was allowed to stand for 6 hours. If the leak was found to be airtight, the reactor was opened and the raw materials were added. The reactor was then purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 3 MPa, and the reactor was slowly heated to 235°C under stirring. The reaction was allowed to proceed for 5 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S4.

[0078] Example 5

[0079] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 0.

[0080] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0081] Raw material preparation:

[0082] Weigh out 22.8g of ethylenediaminetetraethanol, 36g of ethylenediamine, and 5.88g of supported amination catalyst.

[0083] In the supported amination catalyst, the support is a molecular sieve with a particle size of 0.2 mm; the active components and additives supported in the catalyst are as follows: 15% Ni, 10% Cu, 10% Re, 1% Cr, 1.5% Fe, and 2.5% Zn.

[0084] Preparation process:

[0085] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the leak was found to be airtight, the reactor was opened, raw materials were added, and the reactor was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 3 MPa, and the reactor was slowly heated to 200°C under stirring. The reaction was allowed to proceed for 6 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S5.

[0086] Example 6

[0087] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 0.

[0088] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0089] Raw material preparation:

[0090] Weigh out 22.8g of ethylenediaminetetraethanol, 48g of ethylenediamine and 5.664g of supported amination catalyst.

[0091] In the supported amination catalyst, the support is a molecular sieve with a particle size of 0.1 mm; the active components and additives supported in the catalyst are as follows: 30% Ni, 5% Cu, 8% Re, 0.5% Cr, 1% Fe, and 2% Zn.

[0092] Preparation process:

[0093] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and the reactor was checked for leaks using foam water. The reactor was allowed to stand for 6 hours. If the leak was found to be airtight, the reactor was opened and the raw materials were added. The reactor was then purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 1.5 MPa, and the reactor was stirred. The temperature was slowly increased to 210°C, and the reaction was allowed to proceed for 4 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S6.

[0094] Example 7

[0095] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 1.

[0096] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0097] Raw material preparation:

[0098] Weigh out 22.8g of ethylenediaminetetraethanol, 72.1g of diethylenetriamine and 4.745g of supported amination catalyst.

[0099] In the supported amination catalyst, the support is a molecular sieve with a particle size of 3 mm; the active components and additives supported in the catalyst are as follows: 30% Ni, 10% Cu, 5% Re, 2% Cr, 1.5% Fe, and 1% Zn.

[0100] Preparation process:

[0101] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the leak was found to be airtight, the reactor was opened, raw materials were added, and the reactor was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 2 MPa, and the reactor was slowly heated to 240°C under stirring. The reaction was allowed to proceed for 5 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S7.

[0102] Example 8

[0103] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 2.

[0104] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0105] Raw material preparation:

[0106] Weigh out 22.8g of ethylenediaminetetraethanol, 109.5g of triethylenetetramine and 13.23g of supported amination catalyst.

[0107] The supported amination catalyst has an alumina support with a particle size of 5 mm. The active components and additives supported in the catalyst are as follows: 25% Ni, 10% Cu, 10% Re, 1% Cr, 2.5% Fe, and 2% Zn.

[0108] Preparation process:

[0109] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the airtightness was good, the reactor was opened, raw materials were added, and the reactor was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas at 2.5 MPa was then introduced, and the reactor was slowly heated to 230°C under stirring. The reaction was allowed to proceed for 3 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S8.

[0110] Example 9

[0111] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 3.

[0112] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0113] Raw material preparation:

[0114] Weigh out 22.8g of ethylenediaminetetraethanol, 151.2g of tetraethylenepentamine and 10.44g of supported amination catalyst.

[0115] In the supported amination catalyst, the support is alumina with a particle size of 2 mm; the active components and additives supported in the catalyst are as follows: 30% Ni, 8% Cu, 7% Re, 1.5% Cr, 2% Fe, and 2% Zn.

[0116] Preparation process:

[0117] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the leak was found to be airtight, the reactor was opened, raw materials were added, and the reactor was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 3 MPa, and the reactor was slowly heated to 240°C under stirring. The reaction was allowed to proceed for 5 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S9.

[0118] Example 10

[0119] This embodiment provides a clay stabilizer, wherein the value of n in the structural formula of the clay stabilizer in this embodiment is 4.

[0120] The method for preparing the clay stabilizer in this embodiment includes the following steps:

[0121] Raw material preparation:

[0122] Weigh out 22.8g of ethylenediaminetetraethanol, 150.8g of pentaethylenehexamine and 12.152g of supported amination catalyst.

[0123] The supported amination catalyst has an alumina support with a particle size of 0.5 mm. The active components and additives supported in the catalyst are as follows: 320% Ni, 10% Cu, 5% Re, 15% Cr, 1% Fe, and 1% Zn.

[0124] Preparation process:

[0125] A magnetic high-pressure reactor was filled with 6.0 MPa of nitrogen gas, and a foam water test was performed to check for leaks. The reactor was allowed to stand for 6 hours. If the airtightness was good, the reactor was opened, raw materials were added, and the reactor was purged three times with 0.5 MPa nitrogen gas, followed by two purgings with 0.5 MPa hydrogen gas. Hydrogen gas was then introduced at 1.5 MPa, and the reactor was slowly heated to 200°C under stirring. The reaction was allowed to proceed for 4.5 hours. After the reaction was complete, cooling water was introduced to lower the temperature. Once the temperature dropped to 60°C, the pressure was slowly released, and the product was discharged. The catalyst and reaction products were separated by hot filtration to obtain clay stabilizer S10.

[0126] The difference between Example 11 and Example 1 is that the supported amination catalyst in Example 11 is supported by aluminum oxide with a particle size of 0.5 mm; the active components and additives supported in the catalyst are as follows: 30% Ni, 6% Cu, 11% Re, 2.3% Cr, 2.6% Fe, and 1.5% Zn.

[0127] The difference between Example 12 and Example 1 is that the supported amination catalyst in Example 12 is supported by aluminum oxide with a particle size of 6 mm; the active components and additives supported in the catalyst are as follows: 30% Ni, 6% Cu, 10% Re, 1.8% Cr, 2.5% Fe, and 1.5% Zn.

[0128] Comparative Example

[0129] Comparative Example 1

[0130] Commercially available clay stabilizer HJZ-100 was used as Comparative Example 1.

[0131] The difference between Comparative Example 2 and Example 1 is that the reaction temperature is 190°C.

[0132] The difference between Comparative Example 3 and Example 1 is that the reaction temperature is 250°C.

[0133] The difference between Comparative Example 4 and Example 1 is that the amount of pentaethylenehexamine used is 201.3g (the molar ratio of ethylenediaminetetraethanol and polyethyleneamine is 1:9).

[0134] The difference between Comparative Example 5 and Example 1 is that the amount of pentaethylenehexamine used is 122.6 g (the molar ratio of ethylenediaminetetraethanol and polyethyleneamine is 1:5.5).

[0135] Performance testing

[0136] The anti-swelling rate of the clay stabilizers prepared in the examples and comparative examples and the commercially available clay stabilizers at a mass concentration of 0.1% was tested in accordance with the "Sy / T5971-2016 Performance Evaluation Method of Clay Stabilizers for Water Injection".

[0137] The wash resistance of the clay stabilizers prepared in the examples and comparative examples and the commercially available clay stabilizers at a mass concentration of 0.1% after three water washes was tested in accordance with the "Sy / T5971-2016 Performance Evaluation Method of Clay Stabilizers for Water Injection".

[0138] The anti-swelling and water-washing properties of clay stabilizers S1-S10 and commercially available clay stabilizers prepared in the examples and comparative examples are shown in Table 1.

[0139] Table 1 Performance Evaluation Results

[0140] sample Room temperature anti-swelling rate, % Washing resistance, % Example 1 S1 90.81 100.00 Example 2 S2 89.28 97.25 Example 2 S3 86.45 98.23 Example 4 S4 88.68 97.76 Example 5 S5 87.21 97.64 Example 6 S6 88.15 98.09 Example 7 S7 89.10 100.00 Example 8 S8 90.09 99.87 Example 9 S9 90.15 100.00 Example 10 S10 90.54 100.00 Example 11 S11 85.29 95.85 Example 12 S12 84.32 94.92 Comparative Example 1 Commercially available samples 52.35 75.12 Comparative Example 2 D1 72.12 80.32 Comparative Example 3 D2 65.35 85.12 Comparative Example 4 D3 80.12 85.33 Comparative Example 5 D4 75.60 74.33

[0141] As can be seen from the test results of Examples 1-10 in the table above, the clay stabilizer prepared by the method of this application has excellent anti-swelling rate and water washability. Specifically, the anti-swelling rate of the clay stabilizer prepared by the method of this application at room temperature is all above 87%, reaching a maximum of 90.81%; the water washability is all above 97%, reaching a maximum of 100%. In contrast, the anti-swelling rate of commercially available clay stabilizers at room temperature is only 52.35%, and the water washability is only 75.12%. Compared with commercially available clay stabilizers, the anti-swelling rate of the clay stabilizer prepared by this application is increased by up to 73.47% at room temperature (calculated as a percentage increase), and the water washability is increased by up to 33.12%. Furthermore, the preparation process of this application involves a one-step reaction to prepare the clay stabilizer, which is very simple, does not use organic solvents, and is easy to industrialize; that is, this application obtains a product with excellent performance through a simple preparation process.

[0142] Furthermore, regarding the preparation process itself, analysis of Comparative Examples 2 and 3 reveals that excessively high or low temperatures affect the final material structure of the clay stabilizer, leading to varying degrees of performance degradation. In addition, analysis of Comparative Example 4 shows that when excessive amines are used, the anti-swelling rate and washability of the clay stabilizer decrease to some extent. This is because a higher amount of amines participates in the reaction, resulting in a more complex material structure and larger molecular weight in the obtained clay stabilizer. Consequently, the clay stabilizer cannot effectively penetrate the clay layers, reducing its interlayer binding effect. Comparative Example 5, on the other hand, shows insufficient amines, failing to meet the requirements of the clay stabilizer material of this application and thus failing to achieve the technical effects of the clay stabilizer described in this application.

[0143] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for preparing a clay stabilizer, characterized in that, Includes the following steps: In a nitrogen atmosphere, ethylenediaminetetraethanol, polyethyleneamine, and a supported amination catalyst are added to a reactor, wherein the molar ratio of ethylenediaminetetraethanol to polyethyleneamine is 1:(6-8.3); then hydrogen is introduced, stirring is started, and the reaction is carried out at a temperature of 200-240℃ for 3-6 hours. After the reaction is completed, the clay stabilizer is separated.

2. The method for preparing a clay stabilizer according to claim 1, characterized in that, The polyethyleneamine is at least one of ethylenediamine, diethylenetriamine, triethylenetetramine, tetraethylenepentamine, and pentaethylenehexamine.

3. The method for preparing a clay stabilizer according to claim 1, characterized in that, The supported amination catalyst is composed of a main active component, an auxiliary agent, and a support. The main active component is a mixture of Ni, Cu, and Re; the auxiliary agent is one or more of Cr, Fe, or Zn; and the support is a molecular sieve or alumina.

4. The method for preparing a clay stabilizer according to claim 3, characterized in that, In the main active component, the Ni loading is 15-30% of the weight of the supported amination catalyst, the Cu loading is 5-10% of the weight of the supported amination catalyst, and the Re loading is 5-10% of the weight of the supported amination catalyst.

5. The method for preparing a clay stabilizer according to claim 3, characterized in that, In the additives, the loading of Cr is 0.5-2% of the weight of the supported amination catalyst, the loading of Fe is 1-2.5% of the weight of the supported amination catalyst, and the loading of Zn is 0.5-2.5% of the weight of the supported amination catalyst.

6. The method for preparing a clay stabilizer according to claim 1, characterized in that, The supported amination catalyst has a particle size of 0.1–5 mm.

7. The method for preparing a clay stabilizer according to claim 1, characterized in that, The amount of the supported amination catalyst added is 5-10% of the total mass of ethylenediaminetetraethanol and ethyleneamine.

8. The method for preparing a clay stabilizer according to claim 1, characterized in that, Nitrogen gas was introduced into the magnetic high-pressure reactor for a leak test. Then, ethylenediaminetetraethanol, ethyleneamine, and the supported amination catalyst were added to the magnetic high-pressure reactor, and the reactor was tightened. The magnetic high-pressure reactor was then purged with nitrogen gas. Hydrogen gas was then introduced to purge the reactor. Finally, hydrogen gas was introduced into the reactor.

9. The method for preparing a clay stabilizer according to claim 1, characterized in that, During the reaction, the initial partial pressure of hydrogen is 1.5–3.0 MPa.

10. A clay stabilizer prepared by the preparation method according to any one of claims 1 to 9, characterized in that, The clay stabilizer comprises a substance with the structure shown in formula (1): Where n is any integer from 0 to 4.

11. The application of a clay stabilizer prepared by the preparation method according to any one of claims 1 to 9, characterized in that, The clay stabilizer is used in oilfield oil production technology.

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