Clay stabilizer containing dihydroxyl quaternary ammonium salt and preparation method thereof

Abstract

The invention relates to the technical field of oilfield chemistry, in particular to a clay stabilizer containing dihydroxyl quaternary ammonium salt and a preparation method thereof, and the preparation method of the clay stabilizer containing dihydroxyl quaternary ammonium salt comprises the following steps: mixing required amounts of tetramethylethylenediamine, 3-chloro-2-hydroxypropyl trimethyl ammonium chloride and a hydrogen bond donor for reaction to obtain the clay stabilizer containing dihydroxyl quaternary ammonium salt. And after the reaction is ended, obtaining the clay stabilizer containing the dihydroxyl quaternary ammonium salt. The clay stabilizer containing dihydroxyl quaternary ammonium salt is high in charge density and remarkable in clay expansion prevention effect; the fabric has the characteristic of multi-point adsorption and is high in washing resistance; the polymer is composed of small molecular weight compounds and can be used for transformation of low-permeability and ultra-low-permeability reservoirs. And meanwhile, the fracturing fluid has good compatibility with the fracturing fluid, the influence on the viscosity of the fracturing fluid is small, and the sand-carrying performance of the fracturing fluid can be guaranteed while reservoir protection is realized. The preparation method of the clay stabilizer containing the dihydroxyl quaternary ammonium salt is simple in process, easy to control and implement and suitable for industrial large-scale production.

Description

Technical Field

[0001] This invention relates to the field of oilfield chemical technology, specifically to a clay stabilizer containing dihydroxy-4-quaternary ammonium salt and its preparation method. Background Technology

[0002] Clay minerals are widely present in oil reservoirs, with 97% of the world's oil reservoirs containing clay minerals to varying degrees. The main clay mineral categories are montmorillonite, kaolinite, illite, chlorite, illite-montmorillonite mixed layers, and chlorite-montmorillonite mixed layers. These clays swell when they come into contact with water or water-based substances during water injection, acidizing, and fracturing. Improper measures during oil and gas reservoir development can cause clay minerals to expand, disperse, and migrate, thereby clogging formation pores and throats, reducing formation permeability, causing formation damage, and blocking formation channels, leading to a decrease in formation permeability. Therefore, for reservoirs with high clay content and high water sensitivity, any intrusion of water-based working fluids during drilling, cementing, water injection, fracturing, acidizing, well workover, and well kill operations can potentially cause water-sensitive damage.

[0003] The use of clay stabilizers can effectively prevent the hydration, swelling, dispersion, and migration of clay minerals. The use of clay stabilizers in reservoir protection is an effective means of protecting water-sensitive formations. Correct use of clay stabilizers is an effective measure for reservoir protection and improving oil well production.

[0004] Chinese patent document CN117886980A discloses a quaternary ammonium salt clay stabilizer and its preparation method. The quaternary ammonium salt clay stabilizer comprises a polymer generated by the self-polymerization of dimethyl diallyl ammonium chloride. The weight-average molecular weight of the quaternary ammonium salt clay stabilizer is less than 20,000, the radius of gyration of the quaternary ammonium salt clay stabilizer is 0.4-0.6 nm, the cationicity of the quaternary ammonium salt clay stabilizer is 3-4 mmol / g, the anti-swelling rate of the quaternary ammonium salt clay stabilizer is >85%, the water washability is >80%, and the temperature resistance is ≥160℃.

[0005] Chinese patent document CN119264895A discloses a petroleum-based antibacterial clay stabilizer and its preparation method. The antibacterial clay stabilizer is obtained by mixing a slow-release neutralizing liquid and a stabilizing agent liquid. The slow-release neutralizing liquid includes polyvinylpyrrolidone, cationic metal releasing particles, and a reducing agent. The stabilizing agent liquid includes a stabilizing agent, deionized water, glacial acetic acid, polyether polyol, and potassium hydroxide solution. With its small molecular weight, it is easy to insert into the clay interlayer, and its long outer chain has strong hydrophobicity, which can effectively and stably retain colloidal molecules, thereby stably releasing metal cations and enhancing the anti-swelling effect of clay.

[0006] Chinese patent document CN109054798A discloses a method for preparing a high-temperature resistant clay stabilizer for oil fields. This clay stabilizer is prepared by an addition reaction using γ-(2,3-epoxypropoxy)propyltrimethoxysilane and trimethylamine hydrochloride as raw materials and anhydrous ethanol as a solvent.

[0007] However, existing clay stabilizers still have many problems. Inorganic salt clay stabilizers (such as KCl, NH4Cl, CaCl2, etc.) have the advantages of low price and good short-term anti-swelling effect; however, their disadvantages are also very obvious: short anti-swelling period, poor effect on inhibiting particle migration, and negative impact on the performance of the injected fluid. Inorganic cationic polymer clay stabilizers (such as aluminum hydroxide or zirconium hydroxide) have the advantages of longer anti-swelling period than salts and cationic surfactants, and can effectively prevent particle migration; the disadvantage is poor temperature and acid resistance. Cationic surfactant clay stabilizers have the advantages of strong adsorption, water washability, and the ability to inhibit particle migration; the disadvantage is that they can change the water wettability of the reservoir to oil wettability. Organic cationic polymer clay stabilizers have the advantages of low dosage, high efficiency, strong adsorption capacity, low pH influence, and strong formation adaptability, but they are not suitable for low-permeability reservoirs, as they will aggravate the damage to the permeability of low-permeability reservoirs. Furthermore, the aforementioned types of clay stabilizers have poor compatibility with fracturing fluids, which significantly reduces the viscosity of the fracturing fluid, affects its proppant-carrying capacity, and increases the difficulty of proppant addition during fracturing operations. Therefore, developing clay stabilizers with low dosage, high efficiency, long shelf life, and minimal impact on fracturing fluid performance is of significant practical importance for the efficient development of low-permeability and ultra-low-permeability reservoirs. Summary of the Invention

[0008] This invention provides a clay stabilizer containing dihydroxy-4-quaternary ammonium salt and its preparation method, which overcomes the shortcomings of the prior art and can effectively solve the problems of short shelf life, high cost and poor compatibility of existing clay stabilizers.

[0009] One of the technical solutions of this invention is achieved through the following measures: a method for preparing a clay stabilizer containing dihydroxy-4-quaternary ammonium salt, comprising the following steps: The required amounts of tetramethylethylenediamine, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and hydrogen bond donors are mixed and reacted. After the reaction is terminated, a clay stabilizer containing dihydroxytrimethylammonium salt is obtained.

[0010] The following are further optimizations and / or improvements to one of the above-mentioned technical solutions: The molar ratio of the above tetramethylethylenediamine, 3-chloro-2-hydroxypropyltrimethylammonium chloride and hydrogen bond donor is 1:(1.6 to 2):(1 to 6).

[0011] The hydrogen bond donors mentioned above are one or more of urea, ethylene glycol, and glycerol.

[0012] The above-mentioned reaction termination includes adding a terminator to the reaction system to terminate the reaction.

[0013] The aforementioned terminating agent is water, and the molar ratio of tetramethylethylenediamine to water is 1:(0 to 10).

[0014] The above reactions include the first-stage reaction and the second-stage reaction.

[0015] The reaction temperature in the first stage is 40℃ to 60℃, and the reaction time is 4h to 8h.

[0016] The reaction temperature in the second stage is 80℃ to 100℃, and the reaction time is 6h to 24h.

[0017] The second stage reaction described above is a reflux reaction.

[0018] The second technical solution of the present invention is achieved by the following measures: a clay stabilizer containing dihydroxy-quaternary ammonium salt is prepared by a method for preparing a clay stabilizer containing dihydroxy-quaternary ammonium salt according to one of the technical solutions.

[0019] This invention provides a stabilizer containing dihydroxy-4-quaternary ammonium salt and its preparation method. This clay stabilizer has a high charge density and a significant effect in preventing clay swelling. It also has the characteristics of multi-point adsorption and strong water washing resistance. It is composed of low molecular weight compounds and can be used for the transformation of low-permeability and ultra-low-permeability reservoirs. At the same time, it has good compatibility with fracturing fluids and has little impact on the viscosity of fracturing fluids, thus achieving reservoir protection while ensuring the proppant carrying capacity of fracturing fluids. Detailed Implementation

[0020] This invention is not limited to the following embodiments, and specific implementation methods can be determined according to the technical solutions and actual conditions of this invention. Unless otherwise specified, all chemical reagents and chemicals mentioned in this invention are well-known and commonly used chemical reagents and chemicals in the prior art; unless otherwise specified, all percentages in this invention are mass percentages; unless otherwise specified, all solutions in this invention are aqueous solutions with water as the solvent, for example, hydrochloric acid solution is an aqueous solution of hydrochloric acid; room temperature in this invention generally refers to a temperature between 15°C and 25°C, generally defined as 25°C.

[0021] The present invention will be further described below with reference to embodiments: Example 1: A method for preparing the clay stabilizer containing dihydroxy-4-quaternary ammonium salt, comprising the following steps: The required amounts of tetramethylethylenediamine, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and hydrogen bond donors are mixed and reacted. After the reaction is terminated, a clay stabilizer containing dihydroxytrimethylammonium salt is obtained.

[0022] Example 2: As an optimization of the above example, the molar ratio of tetramethylethylenediamine, 3-chloro-2-hydroxypropyltrimethylammonium chloride and hydrogen bond donor is 1:(1.6 to 2):(1 to 6).

[0023] Example 3: As an optimization of the above examples, the hydrogen bond donor is one or more of urea, ethylene glycol and glycerol.

[0024] Example 4: As an optimization of the above examples, reaction termination includes adding a terminator to the reaction system to terminate the reaction.

[0025] Example 5: As an optimization of the above examples, the terminating agent is water, and the molar ratio of tetramethylethylenediamine to water is 1:(0 to 10).

[0026] Example 6: As an optimization of the above examples, the reaction includes a first-stage reaction and a second-stage reaction.

[0027] Example 7: As an optimization of the above example, the reaction temperature in the first stage is 40°C to 60°C, and the reaction time is 4h to 8h.

[0028] Example 8: As an optimization of the above example, the reaction temperature in the second stage is 80°C to 100°C, and the reaction time is 6h to 24h.

[0029] Example 9: As an optimization of the above examples, the second stage reaction is a reflux reaction.

[0030] The clay stabilizer of the present invention contains a dihydroxy-quaternary ammonium salt, wherein the structural formula of the dihydroxy-quaternary ammonium salt is: .

[0031] The chemical reaction process is as follows: .

[0032] Example 10: The preparation process of this clay stabilizer containing dihydroxy-4-quaternary ammonium salt is as follows: 188g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, 60g of tetramethylethylenediamine and 93g of ethylene glycol were mixed and stirred, and reacted at 60℃ for 6h. Then the temperature was raised to 90℃ and refluxed for 12h. 59g of tap water was added to terminate the reaction. After stirring evenly, a clay stabilizer containing dihydroxytrimethylammonium salt was obtained, denoted as S1.

[0033] Example 11: The preparation process of this clay stabilizer containing dihydroxy-4-quaternary ammonium salt is as follows: 190g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, 60g of tetramethylethylenediamine, 93g of ethylene glycol and 30g of urea were mixed and stirred, and reacted at 50℃ for 4h. Then the temperature was raised to 100℃ and refluxed for 8h. 29g of tap water was added to terminate the reaction and the mixture was stirred evenly to obtain a clay stabilizer containing dihydroxytrimethylammonium salt, denoted as S2.

[0034] Example 12: The preparation process of this clay stabilizer containing dihydroxy-4-quaternary ammonium salt is as follows: 194g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, 60g of tetramethylethylenediamine, and 140g of ethylene glycol were mixed and stirred, and reacted at 50°C for 4 hours. Then, the temperature was raised to 100°C and refluxed for 8 hours. 16g of tap water was added to terminate the reaction and the mixture was stirred evenly to obtain a clay stabilizer containing dihydroxytrimethylammonium salt, denoted as S3.

[0035] Example 13: The preparation process of this clay stabilizer containing dihydroxy-4-quaternary ammonium salt is as follows: 194g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, 60g of tetramethylethylenediamine, and 140g of glycerol were mixed and stirred, and reacted at 50°C for 4 hours. Then, the temperature was raised to 100°C and refluxed for 8 hours. 16g of tap water was added to terminate the reaction and the mixture was stirred evenly to obtain a clay stabilizer containing dihydroxytrimethylammonium salt, denoted as S4.

[0036] Example 14: 194g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, 60g of tetramethylethylenediamine, 120g of urea and 68g of ethylene glycol were mixed and stirred evenly, reacted at 50℃ for 4h, and then heated to 100℃ and refluxed for 8h to obtain a clay stabilizer containing dihydroxytrimethylammonium salt, denoted as S5.

[0037] Comparative Example 1: 60 g of tetramethylethylenediamine and 188 g of 3-chloro-2-hydroxypropyltrimethylammonium chloride were dissolved in 1000 mL of anhydrous ethanol and reacted at 60 °C for 6 h. Then the temperature was raised to 90 °C and refluxed for 12 h. The solvent was recovered by rotary evaporation, ethyl acetate was used as precipitate, and the product was filtered and dried under vacuum to obtain a white solid, which is the dihydroxyquaternary ammonium salt small molecule clay stabilizer with a yield of 98.6%, denoted as D1.

[0038] Comparative Example 2: 60g of tetramethylethylenediamine, 188g of 3-chloro-2-hydroxypropyltrimethylammonium chloride, and 4mol of ethylene glycol were mixed and reacted at 60℃ for 6h, followed by reflux at 90℃ for 12h to obtain a clay stabilizer, denoted as D2.

[0039] Performance testing section: The test method refers to SY / T5971-2024 "Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields". The centrifugation method is used to test the anti-swelling rate, water washability and gel viscosity retention rate.

[0040] Test 1: Evaluation of the anti-swelling rate of clay stabilizers Take 0.7g each of the dihydroxy-tert-ammonium salt clay stabilizers S1 to S4 and clay stabilizers D1 and D2, add 100g of distilled water and shake well to obtain a clay stabilizer solution. Weigh 0.50g of sodium bentonite, put it into a 10mL centrifuge tube, add 10mL of clay stabilizer solution, shake well, let stand at room temperature for 2h, put it into a centrifuge, centrifuge at 1500r / min for 15min, and read the volume V1 of the expanded sodium bentonite.

[0041] The volume V2 of sodium bentonite after expansion is calculated by replacing the clay stabilizer solution with distilled water.

[0042] When kerosene is used instead of clay stabilizer solution, the volume V0 of sodium bentonite after expansion is calculated.

[0043] The formula for calculating the anti-swelling rate B is: .

[0044] Test 2: Evaluation of the water wash resistance of clay stabilizers After centrifuging in Test 1, discard the supernatant in the centrifuge tube, add 10 mL of distilled water, shake well, let stand for 2 hours, put it into a centrifuge, and centrifuge at 1500 r / min for 15 min. Repeat the above operation twice, read the volume of sodium bentonite after expansion, and calculate the anti-swelling rate in the same way as in Test 1.

[0045] Test 3: Evaluation of the gel viscosity retention rate of clay stabilizers Prepare 1000 mL of 0.4% hydroxypropyl guar gum fracturing fluid base solution and divide it into 7 equal parts. One part is a blank sample, and 0.7% (mass fraction) of S1 to S4 and D1 and D2 are added to the other 6 parts respectively.

[0046] The fracturing fluid crosslinking solution formula is: sodium tetraborate 3.0% (mass fraction) and sodium hydroxide 10.0% (mass fraction).

[0047] Hydroxypropyl guar gum fracturing fluid base and fracturing fluid crosslinking fluid were prepared into fracturing fluid gel at a crosslinking ratio of 100:1. Then, the apparent viscosity of two gel samples at 90℃ was measured.

[0048] The formula for calculating the viscosity retention rate of gel is: In the formula, Viscosity retention rate, expressed as a percentage; The apparent viscosity, in mPa·s, is the viscosity after adding clay stabilizer. ρ is the apparent viscosity of the blank sample, in mPa·s.

[0049] The test results for tests 1 to 3 are shown in Table 1.

[0050] Table 1 .

[0051] The results in Table 1 show that the clay stabilizer containing dihydroxy-4-quaternary ammonium salt of the present invention has an anti-swelling rate of over 85%, a water-washed anti-swelling rate of over 83%, and a gel viscosity retention rate of over 90%, which meets the technical specifications for clay stabilizers used in oil and gas field fracturing, acidizing, and water injection. Furthermore, the gel viscosity retention rate is close to or exceeds 100%, which does not reduce the performance of guar gum fracturing fluid.

[0052] In summary, the clay stabilizer containing dihydroxy-4-quaternary ammonium salt of the present invention has the characteristics of high charge density and multiple adsorption sites. It has strong water washing resistance, significant effect in preventing clay swelling, good compatibility with fracturing fluid, and minimal impact on fracturing fluid viscosity, thus achieving reservoir protection while ensuring the proppant carrying capacity of fracturing fluid. Furthermore, the clay stabilizer containing dihydroxy-4-quaternary ammonium salt of the present invention is composed of low molecular weight compounds, which will not cause secondary damage to the reservoir and can be used for the stimulation of low-permeability and ultra-low-permeability reservoirs. At the same time, its preparation method is simple, the reaction process is safe and controllable, and it is suitable for large-scale production.

[0053] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A method for preparing a clay stabilizer containing a dihydroxy-4-hydroxy ammonium salt, characterized in that... Includes the following steps: The required amounts of tetramethylethylenediamine, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and hydrogen bond donors are mixed and reacted. After the reaction is terminated, a clay stabilizer containing dihydroxytrimethylammonium salt is obtained. The molar ratio of tetramethylethylenediamine, 3-chloro-2-hydroxypropyltrimethylammonium chloride, and the hydrogen bond donor is 1:1.6 to 2:1 to 6; The reaction includes a first-stage reaction and a second-stage reaction. The first-stage reaction temperature is 40°C to 60°C and the reaction time is 4h to 8h. The second-stage reaction temperature is 80°C to 100°C and the reaction time is 6h to 24h.

2. The method for preparing the clay stabilizer containing dihydroxy-4-hydroxy ammonium salt according to claim 1, characterized in that... The hydrogen bond donors are one or more of urea, ethylene glycol, and glycerol.

3. The method for preparing the clay stabilizer containing dihydroxy-4-hydroxy ammonium salt according to claim 1 or 2, characterized in that... Reaction termination includes adding a terminator to the reaction system to stop the reaction.

4. The method for preparing the clay stabilizer containing dihydroxy-4-hydroxy ammonium salt according to claim 3, characterized in that... The terminating agent is water, and the molar ratio of tetramethylethylenediamine to water is 1:0 to 10.

5. The method for preparing the clay stabilizer containing dihydroxy-4-hydroxy ammonium salt according to claim 1, characterized in that... The second stage reaction is a reflux reaction.

6. A clay stabilizer containing dihydroxy-4-quaternary ammonium salt prepared by a method according to any one of claims 1 to 5.

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