Anti-swelling agent for fracturing and method for preparing the same

Abstract

The application belongs to the technical field of anti-swelling agent preparation, and particularly relates to a fracturing anti-swelling agent and a preparation method thereof. The fracturing anti-swelling agent is prepared by taking cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride and dimethyl octadecyl [3-(trimethoxysilyl) propyl] ammonium chloride as main anti-swelling components, adding tetrasodium iminodisuccinate to complex metal ions in formation water, taking isomeric tridecanol polyoxyethylene ether as a penetrating component, taking perfluorohexyl ethanol polyoxyethylene ether as a cleanup component, taking sodium D-erythorbate as an antioxidant component, and adding triethanolamine to adjust the alkalinity of the system, so that the raw materials synergize with each other, and the prepared fracturing anti-swelling agent has good anti-swelling rate and water washing resistance.

Description

Technical Field

[0001] This invention belongs to the field of anti-swelling agent preparation technology, specifically relating to an anti-swelling agent for fracturing and its preparation method. Background Technology

[0002] Hydraulic fracturing is a core production enhancement technology for tight oil and gas and shale oil and gas reservoirs, creating reservoir seepage channels through fracturing fluid to create fractures and carry proppant. However, most oil and gas reservoirs are rich in clay minerals such as montmorillonite, illite, and kaolinite. After fracturing fluid is introduced into the well, it can easily cause clay hydration and swelling, dispersion and migration, and blockage of pores and fracture channels, resulting in a significant decrease in reservoir permeability and a rapid decline in the production enhancement effect of fracturing. This is a key problem restricting the efficient development of low-permeability oil and gas reservoirs. Therefore, clay anti-swelling components are usually added to the fracturing fluid system.

[0003] Currently, commonly used anti-swelling agents in oilfields mainly include inorganic salts, ordinary mono-quaternary ammonium salts, and a small amount of silanes. Among them, inorganic potassium salts and ammonium salts are inexpensive and have significant short-term anti-swelling effects, but they have problems such as corrosion of tubing and poor inhibition of particle migration. Traditional mono-alkyl quaternary ammonium salt anti-swelling agents rely on the single cation charge neutralization effect to inhibit clay swelling, but they have few molecular adsorption sites and weak adsorption stability, making it difficult to build a dense hydrophobic protective film on the clay surface. Conventional silane quaternary ammonium salt anti-swelling agents can achieve rock interface anchoring modification, but the hydrolysis film formation rate is slow and the film uniformity is poor under low temperature conditions, and the anti-swelling stability is insufficient when used alone.

[0004] Patent CN 104277817B discloses a high-temperature anti-swelling agent for fracturing and its preparation method. The anti-swelling agent is made from the following raw materials in weight percentages: 10-40% quaternary ammonium salt-type organic cationic polymer, 10-20% shielding agent, and 40-80% inorganic salt. This anti-swelling agent contains a large amount of inorganic salt, which easily crystallizes, increases fracturing fluid residue, and clogs reservoir micropores and fractures. The quaternary ammonium salt-type organic cationic polymer is a quaternary ammonium polymer prepared by polymerizing small-molecule amines with epichlorohydrin. Its molecular structure lacks long-chain hydrophobic alkyl groups, and it can only achieve charge neutralization to prevent swelling, failing to form a dense hydrophobic protective film on the clay surface. Therefore, it suffers from technical shortcomings such as significant reservoir damage, limited permeability, and poor anti-swelling effect.

[0005] Therefore, it is necessary to explore a new type of anti-swelling agent for fracturing. Summary of the Invention

[0006] The purpose of this invention is to provide a fracturing anti-swelling agent with high anti-swelling rate and water washability. In addition, this invention also provides a method for its preparation.

[0007] The fracturing anti-swelling agent of the present invention, by mass percentage, is composed of the following raw materials: 21-23% cationic quaternary ammonium salt, 8-10% hexadecyl dimethyl benzyl ammonium chloride, 5-7% dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, 3-4% tetrasodium iminodisuccinate, 2.0-2.5% isotridecyl alcohol polyoxyethylene ether, 1.2-1.5% perfluorohexyl ethanol polyoxyethylene ether, 0.1-0.15% triethanolamine, 1.0-1.2% sodium D-isoascorbate, and deionized water as the balance. The preparation method of the cationic quaternary ammonium salt comprises the following steps: ① adding 1,3- Bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane and anhydrous isopropanol were used. The air in the reactor was purged with nitrogen 6-8 times, and the temperature was raised to 60-65℃. Oleamide propyl dimethylamine was added dropwise to the above solution under stirring. After the addition was completed, the reaction was maintained at the temperature to prepare a tertiary amine intermediate. ② The prepared tertiary amine intermediate was added to the reaction apparatus, and then anhydrous isopropanol was added. The air in the reactor was purged with nitrogen 3-5 times, and the reaction system was raised to 50℃. Finally, 2,3-epoxypropyltrimethylammonium chloride solution was added dropwise. After the addition was completed, the temperature was raised to 65-68℃ and the reaction was maintained at the temperature for 9 hours. After the reaction was completed, a cationic quaternary ammonium salt was prepared by post-treatment.

[0008] In the preparation method of cationic quaternary ammonium salt, step ① involves a heat preservation reaction at a temperature of 65-70℃ for 8 hours.

[0009] In step ① of the preparation method of cationic quaternary ammonium salt, the dripping time of oleamidopropyl dimethylamine is 2.5 h.

[0010] In step ① of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0011] In step ① of the preparation method of cationic quaternary ammonium salt, the molar ratio of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane to oleamide propyl dimethylamine is 1:2.05.

[0012] In step ① of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 58% of the total mass of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane, anhydrous isopropanol, and oleamide propyl dimethylamine.

[0013] In step ② of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0014] Preparation method of cationic quaternary ammonium salt, step ②: Nitrogen gas is purged throughout the reaction process to isolate oxygen and water vapor.

[0015] In step ② of the preparation method of cationic quaternary ammonium salt, the 2,3-epoxypropyltrimethylammonium chloride solution is prepared by adding 2,3-epoxypropyltrimethylammonium chloride to a mixed solution of ethanol and isopropanol and stirring at 40°C for 70 min. The 2,3-epoxypropyltrimethylammonium chloride accounts for 35% of the total mass of 2,3-epoxypropyltrimethylammonium chloride, ethanol, and isopropanol, and the mass ratio of ethanol to isopropanol is 1:2.

[0016] In step ② of the preparation method of cationic quaternary ammonium salt, the molar ratio of the tertiary amine intermediate to the 2,3-epoxypropyltrimethylammonium chloride contained in the 2,3-epoxypropyltrimethylammonium chloride solution is 1:2.2.

[0017] In step ② of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 50% of the total mass of the tertiary amine intermediate, anhydrous isopropanol, and 2,3-epoxypropyltrimethylammonium chloride solution.

[0018] In step ② of the preparation method of cationic quaternary ammonium salt, the dropping time of 2,3-epoxypropyltrimethylammonium chloride solution is 2.5 h.

[0019] The post-treatment described in step ② of the preparation method of the cationic quaternary ammonium salt is as follows: heating to 70-72℃, vacuum distilling at -0.090MPa to recover anhydrous isopropanol, purging with nitrogen for 30 min to remove volatile impurities, adding a deionized water-ethanol mixture while stirring and while hot, the mass of the deionized water-ethanol mixture being 3 times the mass of the product, and ethanol accounting for 15% of the total mass of the mixture, stirring and dissolving at 50-60℃ for 50-60 min to prepare the cationic quaternary ammonium salt.

[0020] The preparation method of the fracturing anti-swelling agent of the present invention comprises the following steps: (1) Add 70% of the total mass of deionized water to the reaction apparatus, add triethanolamine and stir for 5-10 min, then add tetrasodium iminodisuccinate and sodium D-isoascorbate. (2) Add cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride and dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride sequentially to the reaction system prepared in step (1); (3) Add isomeric tridecyl alcohol polyoxyethylene ether and perfluorohexyl ethanol polyoxyethylene ether sequentially to the reaction system prepared in step (2); (4) Add 30% of the total mass of deionized water to the reaction system prepared in step (3), stir at room temperature for 40-50 min, and then let it stand to mature to prepare the anti-swelling agent for fracturing.

[0021] In step (1), add tetrasodium iminodisuccinate and stir for 10-15 min, then add sodium D-isoascorbate and stir for 15-20 min.

[0022] In step (2), add cationic quaternary ammonium salt and stir for 25-35 min, then add hexadecyl dimethyl benzyl ammonium chloride and stir for 20-30 min, and finally add dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride and stir for 30-35 min.

[0023] In step (3), add isomeric tridecyl alcohol polyoxyethylene ether and stir for 20-23 min, then add perfluorohexyl ethanol polyoxyethylene ether and stir for 20-25 min.

[0024] In steps (1) to (3), the stirring speed is 200-300 r / min and the stirring temperature is room temperature.

[0025] In step (4), the temperature for standing and ripening is room temperature, and the time for standing and ripening is 2 hours.

[0026] Compared with the prior art, the present invention has the following advantages: (1) The anti-swelling agent for fracturing described in this invention uses cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride, and dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride as the main anti-swelling components, adds tetrasodium iminodisuccinate to complex metal ions in formation water, uses isomeric tridecyl alcohol polyoxyethylene ether as a permeation component, perfluorohexyl ethanol polyoxyethylene ether as a drainage aid component, and sodium D-isoascorbate as an antioxidant component. At the same time, triethanolamine is added to adjust the alkalinity of the system. Thus, the synergistic effect between the raw materials ensures that the prepared anti-swelling agent for fracturing has a good anti-swelling rate and water washability.

[0027] (2) The anti-swelling agent for fracturing described in this invention uses cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride, and dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride as the main anti-swelling components, with each raw material acting synergistically. Hexadecyl dimethyl benzyl ammonium chloride is a single-chain cationic surfactant. Its quaternary ammonium positive charge is adsorbed onto the negatively charged sites on the surface of clay particles through electrostatic attraction. At the same time, the long hexadecyl chain can intercalate into the interlayer gaps of clay layers and / or cover the outer surface of the particles, forming a hydrophobic hydrocarbon film that hinders the penetration of water molecules, thereby inhibiting hydration swelling. The dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride molecule contains C 18Alkyl hydrophobic chains can form a hydrophobic coating layer on the clay surface, reducing water wettability and hindering free water from penetrating into the interlayer. However, this molecule contains only a single quaternary ammonium site, making it difficult to simultaneously anchor different particles at both ends of the same molecule, thus limiting its ability to flocculate and capture fine clay particles. Therefore, this invention prepares a self-made organosilicon cationic quaternary ammonium salt. First, a bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane is reacted with oleamide propyl dimethylamine to obtain a bistertiary amine intermediate. Then, the bistertiary amine intermediate is reacted with 2,3-epoxypropyltrimethylammonium chloride to undergo an epoxy ring-opening quaternization process, ultimately yielding the organosilicon cationic quaternary ammonium salt. The organosilicon cationic quaternary ammonium salt relies on the intramolecular quaternary ammonium positive charge to efficiently neutralize the negative charge on the clay surface and compress and diffuse the electric double layer, thus inhibiting clay hydration and swelling. It utilizes a twin molecular structure to achieve interparticle bridging and flocculation of clay particles, blocking the migration of fine clay particles. The hydroxyl groups in the molecular chain can form hydrogen bonds with the silanol groups on the clay surface. Combined with a hydrophobic isolation membrane constructed from long alkyl chains, this synergistically enhances adsorption stability and water-resistant anti-swelling ability. The siloxane backbone improves its interfacial compatibility with reservoir aluminosilicate minerals, achieving long-term reservoir protection. Therefore, the synergistic effect of hexadecyl dimethyl benzyl ammonium chloride, dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, and the self-made cationic quaternary ammonium salt reduces the wettability of the clay surface, giving the fracturing anti-swelling agent excellent anti-swelling and swelling-inhibiting properties.

[0028] (3) The fracturing anti-swelling agent of the present invention also contains triethanolamine to adjust the pH of the system to a weakly alkaline state: on the one hand, it avoids the acidic environment from accelerating the hydrolysis of the trimethoxysilyl group in dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, causing premature condensation and formation of siloxane gel, thus preventing its failure; on the other hand, it prevents the strong alkaline conditions from causing severe hydrolysis of the silicon group, ensuring that after the agent enters the formation, it gradually hydrolyzes and anchors in situ under the action of humid heat and water-rock; on the other hand, it stabilizes the chelating activity range of tetrasodium iminodisuccinate, ensuring its complexation efficiency for polyvalent metal ions such as calcium, magnesium, and iron, while optimizing the micelle stability of the cationic quaternary ammonium salt in aqueous solution, avoiding the system stratification or anti-swelling performance degradation caused by acid-base fluctuations. Since the formation water is rich in Ca 2+ Mg 2+ and Fe 3+Tetrasodium iminodisuccinate can effectively complex polyvalent metal ions in the solution, preventing them from forming insoluble flocculent precipitates that clog pores with the anti-swelling component. It also prevents polyvalent metal ions from compressing the electric double layer or forming insoluble complexes with quaternary ammonium salts, thus avoiding interference with micellar stability and anti-swelling uniformity. Isomeric tridecyl alcohol polyoxyethylene ether is used as the wetting and penetrating component. Its nonionic structure significantly reduces the interfacial tension between the agent and the reservoir rock, improves the wetting and spreading properties of the solution on the clay surface, and promotes the penetration of the anti-swelling component into the clay crystal layer, preventing surface adsorption only in the near-wellbore zone. Perfluorohexyl ethanol polyoxyethylene ether is used as the drainage aid component. Utilizing the ultra-low surface tension of the fluorocarbon chain, it weakens formation capillary retention resistance, reduces adsorption residues of the agent in the reservoir pores, and minimizes secondary damage to reservoir permeability. Sodium D-isoascorbate is an antioxidant component that addresses the oxidative chain scission defects of long alkyl structures such as cationic quaternary ammonium salts and silane quaternary ammonium salts under conditions of high temperature, dissolved oxygen, and the coexistence of metal ions. It slows down the oxidative degradation of quaternary ammonium cationic alkyl chains by capturing free radicals and reducing dissolved oxygen content, thus ensuring the molecular structural integrity of the anti-swelling main component. Simultaneously, sodium D-isoascorbate and tetrasodium iminodisuccinate form a synergistic effect: tetrasodium iminodisuccinate chelates Fe... 3+ Transition metal ions inhibit metal-catalyzed oxidation, while sodium D-isoascorbate removes dissolved oxygen and free radicals through reduction. Together, they form an antioxidant-chelation dual protection system, further enhancing the stability and long-term applicability of the agent in high-temperature formation environments.

[0029] (4) The preparation method of the anti-swelling agent for fracturing described in this invention is simple in process, the parameters are easy to control, and the anti-swelling agent prepared has stable performance. Detailed Implementation

[0030] Example 1

[0031] The fracturing anti-swelling agent described in Example 1 is composed of the following raw materials by mass percentage: 22% cationic quaternary ammonium salt, 9% hexadecyl dimethyl benzyl ammonium chloride, 6% dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, 3.5% tetrasodium iminodisuccinate, 2.3% isotridecyl alcohol polyoxyethylene ether, 1.4% perfluorohexyl ethanol polyoxyethylene ether, 0.12% triethanolamine, 1.1% sodium D-isoascorbate, and deionized water as the balance. Specifically, ① 1,3-bis(3-glycidyl etheroxypropyl)tetramethyl... Disiloxane and anhydrous isopropanol were used. The air in the reactor was purged with nitrogen seven times, and the temperature was raised to 63°C. Oleamide propyl dimethylamine was added dropwise to the above solution under stirring. After the addition was completed, the reaction was maintained at the temperature to prepare a tertiary amine intermediate. ② The prepared tertiary amine intermediate was added to the reaction apparatus, and then anhydrous isopropanol was added. The air in the reactor was purged with nitrogen four times, and the reaction system was raised to 50°C. Finally, 2,3-epoxypropyltrimethylammonium chloride solution was added dropwise. After the addition was completed, the temperature was raised to 67°C and the reaction was maintained at the temperature for 9 hours. After the reaction was completed, a cationic quaternary ammonium salt was prepared by post-treatment.

[0032] In the preparation method of cationic quaternary ammonium salt, step ① involves a heat preservation reaction at 67℃ for 8 hours.

[0033] In step ① of the preparation method of cationic quaternary ammonium salt, the dripping time of oleamidopropyl dimethylamine is 2.5 h.

[0034] In step ① of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0035] In step ① of the preparation method of cationic quaternary ammonium salt, the molar ratio of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane to oleamide propyl dimethylamine is 1:2.05.

[0036] In step ① of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 58% of the total mass of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane, anhydrous isopropanol, and oleamide propyl dimethylamine.

[0037] In step ② of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0038] Preparation method of cationic quaternary ammonium salt, step ②: Nitrogen gas is purged throughout the reaction process to isolate oxygen and water vapor.

[0039] In step ② of the preparation method of cationic quaternary ammonium salt, the 2,3-epoxypropyltrimethylammonium chloride solution is prepared by adding 2,3-epoxypropyltrimethylammonium chloride to a mixed solution of ethanol and isopropanol and stirring at 40°C for 70 min. The 2,3-epoxypropyltrimethylammonium chloride accounts for 35% of the total mass of 2,3-epoxypropyltrimethylammonium chloride, ethanol, and isopropanol, and the mass ratio of ethanol to isopropanol is 1:2.

[0040] In step ② of the preparation method of cationic quaternary ammonium salt, the molar ratio of the tertiary amine intermediate to the 2,3-epoxypropyltrimethylammonium chloride contained in the 2,3-epoxypropyltrimethylammonium chloride solution is 1:2.2.

[0041] In step ② of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 50% of the total mass of the tertiary amine intermediate, anhydrous isopropanol, and 2,3-epoxypropyltrimethylammonium chloride solution.

[0042] In step ② of the preparation method of cationic quaternary ammonium salt, the dropping time of 2,3-epoxypropyltrimethylammonium chloride solution is 2.5 h.

[0043] The post-treatment described in step ② of the preparation method of the cationic quaternary ammonium salt is as follows: heating to 71℃, vacuum distillation at -0.090MPa to recover anhydrous isopropanol, purging with nitrogen for 30 min to remove volatile impurities, adding a deionized water-ethanol mixture while stirring and while hot, the mass of the deionized water-ethanol mixture being 3 times the mass of the product, and ethanol accounting for 15% of the total mass of the mixture, stirring and dissolving at 55℃ for 55 min to prepare the cationic quaternary ammonium salt.

[0044] The preparation method of the anti-swelling agent for fracturing described in Example 1 consists of the following steps: (1) Add 70% of the total mass of deionized water to the reaction apparatus, add triethanolamine and stir for 7 min, then add tetrasodium iminodisuccinate and sodium D-isoascorbate. (2) Add cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride and dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride sequentially to the reaction system prepared in step (1); (3) Add isomeric tridecyl alcohol polyoxyethylene ether and perfluorohexyl ethanol polyoxyethylene ether sequentially to the reaction system prepared in step (2); (4) Add 30% of the total mass of deionized water to the reaction system prepared in step (3), stir at room temperature for 43 min, and then let it stand to mature to prepare the anti-swelling agent for fracturing.

[0045] In step (1), add tetrasodium iminodisuccinate and stir for 13 minutes, then add sodium D-isoascorbate and stir for 17 minutes.

[0046] In step (2), add cationic quaternary ammonium salt and stir for 30 min, then add hexadecyl dimethyl benzyl ammonium chloride and stir for 25 min, and finally add dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride and stir for 33 min.

[0047] In step (3), add isomeric tridecyl alcohol polyoxyethylene ether and stir for 21 min, then add perfluorohexyl ethanol polyoxyethylene ether and stir for 23 min.

[0048] In steps (1) to (3), the stirring speed is 250 r / min and the stirring temperature is room temperature.

[0049] In step (4), the temperature for standing and ripening is room temperature, and the time for standing and ripening is 2 hours.

[0050] According to the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the anti-swelling agent for fracturing prepared in Example 1 was formulated into a 1.0% mass fraction aqueous solution, mixed with sodium-based bentonite, and then kept at a constant temperature of 25°C for 2 hours. After centrifugation, the anti-swelling rate was calculated. The anti-swelling rate after being kept at a constant temperature of 25°C for 2 hours was 92.7%.

[0051] According to section 7.4 of the "Sy / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the water wash resistance was tested. After standing at room temperature for 2 hours, the retention rate after 3 water washes was 90.3%.

[0052] Example 2

[0053] The anti-swelling agent for fracturing described in Example 2 is composed of the following raw materials by mass percentage: 21% cationic quaternary ammonium salt, 10% hexadecyl dimethyl benzyl ammonium chloride, 5% dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, 3% tetrasodium iminodisuccinate, 2.5% isotridecyl alcohol polyoxyethylene ether, 1.2% perfluorohexyl ethanol polyoxyethylene ether, 0.1% triethanolamine, 1.0% sodium D-isoascorbate, and deionized water as the balance. The preparation method of the cationic quaternary ammonium salt comprises the following steps: ① Adding 1,3-bis(3-glycidyl)propanediol to the reaction apparatus... Oleamide propyl dimethylamine was added dropwise to the above solution with oleamide propyl dimethylamine and anhydrous isopropanol. The air in the reactor was purged with nitrogen 6 times, and the temperature was raised to 60°C. After stirring, the solution was kept at a constant temperature to prepare a tertiary amine intermediate. The prepared tertiary amine intermediate was added to the reaction apparatus, and then anhydrous isopropanol was added. The air in the reactor was purged with nitrogen 3 times, and the reaction system was raised to 50°C. Finally, 2,3-epoxypropyltrimethylammonium chloride solution was added dropwise. After the addition was completed, the temperature was raised to 65°C and the reaction was kept at a constant temperature for 9 hours. After the reaction was completed, the cationic quaternary ammonium salt was prepared by post-treatment.

[0054] In the preparation method of cationic quaternary ammonium salt, step ① involves a heat preservation reaction at 65℃ for 8 hours.

[0055] In step ① of the preparation method of cationic quaternary ammonium salt, the dripping time of oleamidopropyl dimethylamine is 2.5 h.

[0056] In step ① of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0057] In step ① of the preparation method of cationic quaternary ammonium salt, the molar ratio of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane to oleamide propyl dimethylamine is 1:2.05.

[0058] In step ① of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 58% of the total mass of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane, anhydrous isopropanol, and oleamide propyl dimethylamine.

[0059] In step ② of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0060] Preparation method of cationic quaternary ammonium salt, step ②: Nitrogen gas is purged throughout the reaction process to isolate oxygen and water vapor.

[0061] In step ② of the preparation method of cationic quaternary ammonium salt, the 2,3-epoxypropyltrimethylammonium chloride solution is prepared by adding 2,3-epoxypropyltrimethylammonium chloride to a mixed solution of ethanol and isopropanol and stirring at 40°C for 70 min. The 2,3-epoxypropyltrimethylammonium chloride accounts for 35% of the total mass of 2,3-epoxypropyltrimethylammonium chloride, ethanol, and isopropanol, and the mass ratio of ethanol to isopropanol is 1:2.

[0062] In step ② of the preparation method of cationic quaternary ammonium salt, the molar ratio of the tertiary amine intermediate to the 2,3-epoxypropyltrimethylammonium chloride contained in the 2,3-epoxypropyltrimethylammonium chloride solution is 1:2.2.

[0063] In step ② of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 50% of the total mass of the tertiary amine intermediate, anhydrous isopropanol, and 2,3-epoxypropyltrimethylammonium chloride solution.

[0064] In step ② of the preparation method of cationic quaternary ammonium salt, the dropping time of 2,3-epoxypropyltrimethylammonium chloride solution is 2.5 h.

[0065] The post-treatment described in step ② of the preparation method of the cationic quaternary ammonium salt is as follows: heating to 70℃, vacuum distilling at -0.090MPa to recover anhydrous isopropanol, purging with nitrogen for 30 min to remove volatile impurities, adding a deionized water-ethanol mixture while stirring and while hot, the mass of the deionized water-ethanol mixture being 3 times the mass of the product, and ethanol accounting for 15% of the total mass of the mixture, stirring and dissolving at 50℃ for 60 min to prepare the cationic quaternary ammonium salt.

[0066] The preparation method of the anti-swelling agent for fracturing described in Example 2 consists of the following steps: (1) Add 70% of the total mass of deionized water to the reaction apparatus, add triethanolamine and stir for 5 min, then add tetrasodium iminodisuccinate and sodium D-isoascorbate. (2) Add cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride and dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride sequentially to the reaction system prepared in step (1); (3) Add isomeric tridecyl alcohol polyoxyethylene ether and perfluorohexyl ethanol polyoxyethylene ether sequentially to the reaction system prepared in step (2); (4) Add 30% of the total mass of deionized water to the reaction system prepared in step (3), stir at room temperature for 40 min, and then let it stand to mature to prepare the anti-swelling agent for fracturing.

[0067] In step (1), add tetrasodium iminodisuccinate and stir for 10 min, then add sodium D-isoascorbate and stir for 15 min.

[0068] In step (2), add cationic quaternary ammonium salt and stir for 25 min, then add hexadecyl dimethyl benzyl ammonium chloride and stir for 30 min, and finally add dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride and stir for 30 min.

[0069] In step (3), add isomeric tridecyl alcohol polyoxyethylene ether and stir for 23 min, then add perfluorohexyl ethanol polyoxyethylene ether and stir for 20 min.

[0070] In steps (1) to (3), the stirring speed is 300 r / min and the stirring temperature is room temperature.

[0071] In step (4), the temperature for standing and ripening is room temperature, and the time for standing and ripening is 2 hours.

[0072] According to the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the anti-swelling agent for fracturing prepared in Example 2 was formulated into a 1.0% mass fraction aqueous solution, mixed with sodium-based bentonite, and then kept at a constant temperature of 25°C for 2 hours. After centrifugation, the anti-swelling rate was calculated. The anti-swelling rate after being kept at a constant temperature of 25°C for 2 hours was 90.4%.

[0073] According to section 7.4 of the "Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields" (SY / T 5971-2016), the water wash resistance was tested. After standing at room temperature for 2 hours, the retention rate after 3 water washes was 88.3%.

[0074] Example 3

[0075] The fracturing anti-swelling agent described in Example 3 is composed of the following raw materials by mass percentage: 23% cationic quaternary ammonium salt, 8% hexadecyl dimethyl benzyl ammonium chloride, 7% dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, 4% tetrasodium iminodisuccinate, 2.0% isotridecyl alcohol polyoxyethylene ether, 1.5% perfluorohexyl ethanol polyoxyethylene ether, 0.15% triethanolamine, 1.2% sodium D-isoascorbate, and the balance being deionized water. The preparation method of the cationic quaternary ammonium salt comprises the following steps: ① Adding 1,3-bis(3-glycidyl) ① Tetramethyldisiloxane (etheroxypropyl) and anhydrous isopropanol were used. The air in the reactor was purged with nitrogen 8 times, and the temperature was raised to 65°C. Oleamide propyl dimethylamine was added dropwise to the above solution under stirring. After the addition was completed, the reaction was maintained at the temperature to prepare a tertiary amine intermediate. ② The prepared tertiary amine intermediate was added to the reaction apparatus, and then anhydrous isopropanol was added. The air in the reactor was purged with nitrogen 5 times, and the reaction system was raised to 50°C. Finally, 2,3-epoxypropyltrimethylammonium chloride solution was added dropwise. After the addition was completed, the temperature was raised to 65-68°C and the reaction was maintained at the temperature for 9 hours. After the reaction was completed, a cationic quaternary ammonium salt was prepared by post-treatment.

[0076] In the preparation method of cationic quaternary ammonium salt, step ① involves a heat preservation reaction at 70℃ for 8 hours.

[0077] In step ① of the preparation method of cationic quaternary ammonium salt, the dripping time of oleamidopropyl dimethylamine is 2.5 h.

[0078] In step ① of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0079] In step ① of the preparation method of cationic quaternary ammonium salt, the molar ratio of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane to oleamide propyl dimethylamine is 1:2.05.

[0080] In step ① of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 58% of the total mass of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane, anhydrous isopropanol, and oleamide propyl dimethylamine.

[0081] In step ② of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

[0082] Preparation method of cationic quaternary ammonium salt, step ②: Nitrogen gas is purged throughout the reaction process to isolate oxygen and water vapor.

[0083] In step ② of the preparation method of cationic quaternary ammonium salt, the 2,3-epoxypropyltrimethylammonium chloride solution is prepared by adding 2,3-epoxypropyltrimethylammonium chloride to a mixed solution of ethanol and isopropanol and stirring at 40°C for 70 min. The 2,3-epoxypropyltrimethylammonium chloride accounts for 35% of the total mass of 2,3-epoxypropyltrimethylammonium chloride, ethanol, and isopropanol, and the mass ratio of ethanol to isopropanol is 1:2.

[0084] In step ② of the preparation method of cationic quaternary ammonium salt, the molar ratio of the tertiary amine intermediate to the 2,3-epoxypropyltrimethylammonium chloride contained in the 2,3-epoxypropyltrimethylammonium chloride solution is 1:2.2.

[0085] In step ② of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 50% of the total mass of the tertiary amine intermediate, anhydrous isopropanol, and 2,3-epoxypropyltrimethylammonium chloride solution.

[0086] In step ② of the preparation method of cationic quaternary ammonium salt, the dropping time of 2,3-epoxypropyltrimethylammonium chloride solution is 2.5 h.

[0087] The post-treatment described in step ② of the preparation method of the cationic quaternary ammonium salt is as follows: heating to 72℃, vacuum distilling at -0.090MPa to recover anhydrous isopropanol, purging with nitrogen for 30 min to remove volatile impurities, adding a deionized water-ethanol mixture while stirring and while hot, the mass of the deionized water-ethanol mixture being 3 times the mass of the product, and ethanol accounting for 15% of the total mass of the mixture, stirring and dissolving at 60℃ for 50 min to prepare the cationic quaternary ammonium salt.

[0088] The preparation method of the fracturing anti-swelling agent described in Example 3 consists of the following steps: (1) Add 70% of the total mass of deionized water to the reaction apparatus, add triethanolamine and stir for 10 min, then add tetrasodium iminodisuccinate and sodium D-isoascorbate. (2) Add cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride and dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride sequentially to the reaction system prepared in step (1); (3) Add isomeric tridecyl alcohol polyoxyethylene ether and perfluorohexyl ethanol polyoxyethylene ether sequentially to the reaction system prepared in step (2); (4) Add 30% of the total mass of deionized water to the reaction system prepared in step (3), stir at room temperature for 50 min, and then let it stand to mature to prepare the anti-swelling agent for fracturing.

[0089] In step (1), add tetrasodium iminodisuccinate and stir for 15 minutes, then add sodium D-isoascorbate and stir for 20 minutes.

[0090] In step (2), add cationic quaternary ammonium salt and stir for 35 min, then add hexadecyl dimethyl benzyl ammonium chloride and stir for 20 min, and finally add dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride and stir for 35 min.

[0091] In step (3), add isomeric tridecyl alcohol polyoxyethylene ether and stir for 20 min, then add perfluorohexyl ethanol polyoxyethylene ether and stir for 25 min.

[0092] In steps (1) to (3), the stirring speed is 200 r / min and the stirring temperature is room temperature.

[0093] In step (4), the temperature for standing and ripening is room temperature, and the time for standing and ripening is 2 hours.

[0094] According to the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the anti-swelling agent for fracturing prepared in Example 3 was formulated into a 1.0% mass fraction aqueous solution, mixed with sodium-based bentonite, and then kept at a constant temperature of 25°C for 2 hours. After centrifugation, the anti-swelling rate was calculated. The anti-swelling rate after being kept at a constant temperature of 25°C for 2 hours was 94.2%.

[0095] According to section 7.4 of the "Sy / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the water wash resistance was tested. After standing at room temperature for 2 hours, the retention rate after 3 water washes was 92.0%.

[0096] Comparative Example 1 The preparation method of the anti-swelling agent for fracturing described in Comparative Example 1 is the same as that in Example 1, the only difference being the composition of the raw materials. The anti-swelling agent for fracturing described in Comparative Example 1, by mass percentage, consists of the following raw materials: 9% hexadecyl dimethyl benzyl ammonium chloride, 6% dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, 3.5% tetrasodium iminodisuccinate, 2.3% isotridecyl alcohol polyoxyethylene ether, 1.4% perfluorohexyl ethanol polyoxyethylene ether, 0.12% triethanolamine, 1.1% sodium D-isoascorbate, and the balance being deionized water.

[0097] According to the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the anti-swelling agent for fracturing prepared in Comparative Example 1 was prepared into a 1.0% mass fraction aqueous solution, mixed with sodium-based bentonite, and then kept at a constant temperature of 25℃ for 2 hours. After centrifugation, the anti-swelling rate was calculated. The anti-swelling rate after being kept at a constant temperature of 25℃ for 2 hours was 72.2%.

[0098] According to section 7.4 of the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the water wash resistance was tested. After standing at room temperature for 2 hours, the retention rate after 3 water washes was 62.3%.

[0099] Comparative Example 2 The preparation method of the fracturing anti-swelling agent described in Comparative Example 2 is the same as that in Example 1, the only difference being the composition of the raw materials. The fracturing anti-swelling agent described in Comparative Example 2, by mass percentage, consists of the following raw materials: 22% cationic quaternary ammonium salt, 6% dimethyloctadecyl[3-(trimethoxysilyl)propyl]ammonium chloride, 3.5% tetrasodium iminodisuccinate, 2.3% isotridecyl alcohol polyoxyethylene ether, 1.4% perfluorohexylethanol polyoxyethylene ether, 0.12% triethanolamine, 1.1% sodium D-isoascorbate, and the balance being deionized water. The preparation method of its cationic quaternary ammonium salt is also the same as that in Example 1.

[0100] According to the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the anti-swelling agent for fracturing prepared in Comparative Example 2 was prepared into a 1.0% mass fraction aqueous solution, mixed with sodium-based bentonite, and then kept at a constant temperature of 25℃ for 2 hours. After centrifugation, the anti-swelling rate was calculated. The anti-swelling rate after being kept at a constant temperature of 25℃ for 2 hours was 81.9%.

[0101] According to section 7.4 of the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the water wash resistance was tested. After standing at room temperature for 2 hours, the retention rate after 3 water washes was 74.1%.

[0102] Comparative Example 3 The preparation method of the fracturing anti-swelling agent described in Comparative Example 3 is the same as that in Example 1, the only difference being the composition of the raw materials. The fracturing anti-swelling agent described in Comparative Example 3, by mass percentage, consists of the following raw materials: 22% cationic quaternary ammonium salt, 9% hexadecyl dimethyl benzyl ammonium chloride, 3.5% tetrasodium iminodisuccinate, 2.3% isotridecyl alcohol polyoxyethylene ether, 1.4% perfluorohexyl ethanol polyoxyethylene ether, 0.12% triethanolamine, 1.1% sodium D-isoascorbate, and the balance being deionized water. The preparation method of its cationic quaternary ammonium salt is also the same as that in Example 1.

[0103] According to the "SY / T 5971-2016 Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields", the anti-swelling agent for fracturing prepared in Comparative Example 3 was prepared into a 1.0% mass fraction aqueous solution, mixed with sodium-based bentonite, and then kept at a constant temperature of 25℃ for 2 hours. After centrifugation, the anti-swelling rate was calculated. The anti-swelling rate after being kept at a constant temperature of 25℃ for 2 hours was 85.0%.

[0104] According to section 7.4 of the "Performance Evaluation Method of Clay Stabilizer for Fracturing, Acidizing and Water Injection in Oil and Gas Fields" (SY / T 5971-2016), the water wash resistance was tested. After standing at room temperature for 2 hours, the retention rate after 3 water washes was 77.9%.

[0105] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Although the present invention has been disclosed above with reference to preferred embodiments, it is not intended to limit the present invention. Any person skilled in the art can make some modifications or alterations to the above-disclosed technical content to create equivalent embodiments without departing from the scope of the present invention. Any simple modifications, equivalent changes and alterations made to the above embodiments based on the technical essence of the present invention without departing from the scope of the present invention shall still fall within the scope of the present invention.

Claims

1. A fracturing anti-swelling agent, characterized in that: The product, by mass percentage, is composed of the following raw materials: 21-23% cationic quaternary ammonium salt, 8-10% hexadecyl dimethyl benzyl ammonium chloride, 5-7% dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride, 3-4% tetrasodium iminodisuccinate, 2.0-2.5% isotridecyl alcohol polyoxyethylene ether, 1.2-1.5% perfluorohexyl ethanol polyoxyethylene ether, 0.1-0.15% triethanolamine, 1.0-1.2% sodium D-isoascorbate, and deionized water as the balance. The preparation method of the cationic quaternary ammonium salt comprises the following steps: ① adding 1,3-bis(3-glycidyl)-dimethylbenzyl ammonium chloride to the reaction apparatus. ① A tertiary amine intermediate is prepared by purging the reactor with nitrogen 6-8 times, heating it to 60-65℃, and adding oleamide-propyl dimethylamine dropwise to the above solution while stirring. After the addition is complete, the reaction is maintained at this temperature to prepare a tertiary amine intermediate. ② The prepared tertiary amine intermediate is added to the reaction apparatus, followed by the addition of anhydrous isopropanol. The reactor is purged with nitrogen 3-5 times, and the reaction system is heated to 50℃. Finally, 2,3-epoxypropyltrimethylammonium chloride solution is added dropwise. After the addition is complete, the temperature is raised to 65-68℃ and the reaction is maintained at this temperature for 9 hours. After the reaction is completed, a cationic quaternary ammonium salt is prepared through post-treatment.

2. The anti-swelling agent for fracturing according to claim 1, characterized in that: In the preparation method of cationic quaternary ammonium salt, the temperature of the heat preservation reaction in step ① is 65-70℃, and the heat preservation reaction time is 8h; In the preparation method of cationic quaternary ammonium salt, the time for dropping oilammonium propyl dimethylamine in step ① is 2.5 h; In step ① of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min.

3. The anti-swelling agent for fracturing according to claim 1, characterized in that: In step ① of the preparation method of cationic quaternary ammonium salt, the molar ratio of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane to oleamide propyl dimethylamine is 1:2.

05. In step ① of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 58% of the total mass of 1,3-bis(3-glycidyl etheroxypropyl)tetramethyldisiloxane, anhydrous isopropanol, and oleamide propyl dimethylamine.

4. The anti-swelling agent for fracturing according to claim 1, characterized in that: In step ② of the preparation method of cationic quaternary ammonium salt, the stirring speed is 600 r / min; Step ② of the preparation method of cationic quaternary ammonium salt: Nitrogen gas is purged throughout the reaction process.

5. The anti-swelling agent for fracturing according to claim 1, characterized in that: In step ② of the preparation method of cationic quaternary ammonium salt, the 2,3-epoxypropyltrimethylammonium chloride solution is prepared by adding 2,3-epoxypropyltrimethylammonium chloride to a mixed solution of ethanol and isopropanol and stirring at 40°C for 70 min. The 2,3-epoxypropyltrimethylammonium chloride accounts for 35% of the total mass of 2,3-epoxypropyltrimethylammonium chloride, ethanol, and isopropanol, and the mass ratio of ethanol to isopropanol is 1:

2.

6. The anti-swelling agent for fracturing according to claim 1, characterized in that: In step ② of the preparation method of cationic quaternary ammonium salt, the mass of anhydrous isopropanol accounts for 50% of the sum of the masses of the tertiary amine intermediate, anhydrous isopropanol, and 2,3-epoxypropyltrimethylammonium chloride solution. In step ② of the preparation method of cationic quaternary ammonium salt, the dropping time of 2,3-epoxypropyltrimethylammonium chloride solution is 2.5 h.

7. The anti-swelling agent for fracturing according to claim 1, characterized in that: The post-treatment described in step ② of the preparation method of the cationic quaternary ammonium salt is as follows: heating to 70-72℃, vacuum distilling at -0.090MPa to recover anhydrous isopropanol, purging with nitrogen for 30 min to remove volatile impurities, adding a deionized water-ethanol mixture while stirring and while hot, the mass of the deionized water-ethanol mixture being 3 times the mass of the product, and ethanol accounting for 15% of the total mass of the mixture, stirring and dissolving at 50-60℃ for 50-60 min to prepare the cationic quaternary ammonium salt.

8. A method for preparing the anti-swelling agent for fracturing according to claim 1, characterized in that: It consists of the following steps: (1) Add 70% of the total mass of deionized water to the reaction apparatus, add triethanolamine and stir for 5-10 min, then add tetrasodium iminodisuccinate and sodium D-isoascorbate. (2) Add cationic quaternary ammonium salt, hexadecyl dimethyl benzyl ammonium chloride and dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride sequentially to the reaction system prepared in step (1); (3) Add isomeric tridecyl alcohol polyoxyethylene ether and perfluorohexyl ethanol polyoxyethylene ether sequentially to the reaction system prepared in step (2); (4) Add 30% of the total mass of deionized water to the reaction system prepared in step (3), stir at room temperature for 40-50 min, and then let it stand to mature to prepare the anti-swelling agent for fracturing.

9. The method for preparing the anti-swelling agent for fracturing according to claim 8, characterized in that: In step (1), add tetrasodium iminodisuccinate and stir for 10-15 min, then add sodium D-isoascorbate and stir for 15-20 min; In step (2), add cationic quaternary ammonium salt and stir for 25-35 min, then add hexadecyl dimethyl benzyl ammonium chloride and stir for 20-30 min, and finally add dimethyl octadecyl [3-(trimethoxysilyl)propyl] ammonium chloride and stir for 30-35 min; In step (3), add isomeric tridecyl alcohol polyoxyethylene ether and stir for 20-23 min, then add perfluorohexyl ethanol polyoxyethylene ether and stir for 20-25 min.

10. The method for preparing the anti-swelling agent for fracturing according to claim 8, characterized in that: In steps (1) to (3), the stirring speed is 200-300 r / min and the stirring temperature is room temperature. In step (4), the temperature for standing and ripening is room temperature, and the time for standing and ripening is 2 hours.