Resin-based anti-corrosion plugging agent for plugging oil-water well casing and preparation method thereof

Abstract

The invention discloses a resin-based anti-corrosion plugging agent for oil-water well casing plugging and a preparation method thereof, and relates to the technical field of plugging agent preparation, and the resin-based anti-corrosion plugging agent comprises the following raw materials: modified bisphenol A epoxy resin, amino-terminated nitrile rubber, plugging filler, an anti-corrosion auxiliary agent, modified organic bentonite, 4, 4 '-diphenyl-1, 3-pentanediol monoisobutyrate, an anti-corrosion the component A is prepared from 4, 4 '-diaminodiphenyl sulfone, 2-methylimidazole and gamma-glycidyl ether oxypropyl trimethoxy silane; according to the plugging agent, the modified organic bentonite is added, after the modified organic bentonite is subjected to biquaternary ammonium salt intercalation, nano hybridization and hydrophobic silane end-capping modification, the interlayer spacing is greatly increased, the layered structure is complete and free of collapse at the high temperature of 250 DEG C, the thixotropic property is not obviously attenuated, the high thixotropic index can be achieved with the low dosage, and the plugging agent has the characteristics of low shear flow and high shear viscosity, is easy to pump during construction, and has the good plugging effect. After standing, rapid thickening is performed to prevent underground fluid channeling; the modified bisphenol A epoxy resin has excellent hydrophobicity and oil solubility, has high compatibility with modified bisphenol A epoxy resin, and can be uniformly dispersed without agglomeration after being stirred at a low speed.

Description

Technical Field

[0001] This invention relates to the field of plugging agent preparation technology, and particularly to a resin-based anti-corrosion plugging agent for plugging oil and water well casing and its preparation method. Background Technology

[0002] Corrosion-resistant and leak-sealing agents are special building materials that integrate corrosion protection and rapid sealing functions. They are made by adding high-molecular polymers, rust inhibitors, and densifiers to ordinary cementitious materials. They can effectively resist corrosion from media such as acids, alkalis, and salts, and have the characteristics of rapid solidification, micro-expansion, and high adhesion. They are specially used to quickly seal leaks in concrete structures such as pipes, pools, and basements, and can achieve permanent repairs in humid or wet environments. They are key functional materials in anti-corrosion and waterproofing projects for industrial and civil buildings.

[0003] Traditional resin-based anti-corrosion and plugging agents for oil and water well casing leak sealing suffer from several drawbacks. The base material is prone to aging and powdering at high temperatures, and the cured material is brittle and lacks intrinsic corrosion protection. Thixotropic agents exhibit diminishing thixotropic properties at high temperatures, have poor compatibility with resins, and are prone to agglomeration, leading to flow leakage during construction. Single anti-corrosion additives have weak anti-corrosion mechanisms, their high-temperature effectiveness is easily diminished, and their anti-corrosion cycle is short. Fillers lack sufficient packing density, have weak impermeability and pressure resistance, and are easily lost with formation fluid loss. Toughening agents are prone to debonding at high temperatures, causing the solidified body to crack under temperature and pressure fluctuations. High-temperature curing agents are prone to degradation, have uncontrollable curing rates, and exhibit significant volume shrinkage after curing, easily creating internal voids. Coupling agents have poor bonding effects, with interfaces mostly being physically bonded, and are prone to debonding under high-salinity formation water and high-temperature immersion. Furthermore, they suffer from drawbacks such as difficulty in simultaneously achieving pumpability and flow prevention, low interfacial bonding strength, and weak overall resistance to mineralized water corrosion. Therefore, this invention provides a resin-based anti-corrosion and plugging agent for oil and water well casing leak sealing and its preparation method. Summary of the Invention

[0004] The main objective of this invention is to provide a resin-based anti-corrosion and plugging agent for oil and water well casing with a long shelf life and high β-glucan content, which is applied in the preparation method of the resin-based anti-corrosion and plugging agent for oil and water well casing.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows: This invention provides a resin-based anti-corrosion and plugging agent for plugging leaks in oil and water well casings. The resin-based anti-corrosion and plugging agent for plugging leaks in oil and water well casings comprises the following raw materials: 34-36 parts modified bisphenol A epoxy resin, 3-4 parts amino-terminated nitrile rubber, 43-45 parts plugging filler, 2-3 parts anti-corrosion additive, 1.5-2 parts modified organobentonite, 18-20 parts 4,4'-diaminodiphenyl sulfone, 0.1-0.2 parts 2-methylimidazole, and 1-1.5 parts γ-glycidyl etheroxypropyltrimethoxysilane.

[0006] The molecular weight of amino-terminated nitrile rubber is 3000-4000, the amino-terminated content is ≥1.8mmol / g, and the industrial grade is ≥98%. It makes up for the toughness requirements under extreme temperature and pressure fluctuations and achieves a high-efficiency toughening effect with only a small amount of addition.

[0007] 4,4'-Diaminodiphenyl sulfone is an industrial grade product with a purity of ≥99%, pulverized to a fine powder of 200 mesh, with a melting point of 175-178℃. It does not absorb moisture or clump. The benzene ring and sulfone group structure in its molecule endow it with extremely high thermal stability. Its thermal decomposition temperature exceeds 300℃. At a high temperature of 200-250℃, it undergoes a cross-linking reaction with the epoxy groups of modified bisphenol A epoxy resin at a moderate rate and complete curing, forming a highly dense three-dimensional network solid. It does not degrade or pulverize at high temperatures, and the thermal stability and mechanical strength of the solid are maintained over a long period of time.

[0008] 2-Methylimidazole is an industrial grade product with a purity of ≥99%, in powder form, with a melting point of 145-148℃. It is free of impurities and can efficiently catalyze the ring-opening crosslinking reaction of 4,4'-diaminodiphenyl sulfone and modified bisphenol A epoxy resin. This solves the problems of slow curing rate and incomplete curing at ultra-high temperatures, allowing the sealant to cure within 2-5 hours, meeting the needs of rapid on-site construction.

[0009] Furthermore, the corrosion inhibitor is composed of zinc powder and zinc molybdate mixed in a mass ratio of 2:1.

[0010] The zinc powder has a mesh size of 1200 (particle size ≤10μm), a zinc content of ≥99.9%, is industrial grade, and has a sphericity of ≥0.8.

[0011] Zinc molybdate is industrial grade ≥98% with a particle size ≤5μm.

[0012] Furthermore, the plugging filler is composed of quartz sand, barite powder and mica powder mixed in a mass ratio of 2:1:1.

[0013] The quartz sand has a mesh size of 80 (particle size 180-200μm), a purity of ≥99%, a silica content of ≥98.5%, is industrial grade, and has a moisture content of ≤0.1%. It can build a stable high-temperature rigid skeleton for the plugging agent, greatly improve the compressive strength of the solidified body, and effectively resist the formation pressure downhole.

[0014] The barite powder has a mesh size of 200 (particle size 75μm), a barium sulfate content of ≥95%, is industrial grade, and has a moisture content of ≤0.1%, which improves the packing density of the filler system. The high barium sulfate content makes it extremely chemically stable, with no dissolution or decomposition at 250℃, and it is insoluble in water and oil. It can effectively increase the overall density of the plugging agent system, prevent the plugging agent from flowing through due to low density during downhole operations, and at the same time help to enhance the rigidity and compressive strength of the solidified body.

[0015] The mica powder has a mesh size of 325 (particle size 45μm), a muscovite content of ≥90%, an aspect ratio of ≥80:1, is of industrial grade, and has a moisture content of ≤0.1%. During the curing process of the sealant, it will form a layered barrier structure, which will block the penetration channels of water, oil and corrosive media at the microscopic level, and greatly improve the impermeability and anti-corrosion barrier effect of the solidified body.

[0016] Further, the preparation of the modified organobentonite includes the following steps: adding the intercalating agent to deionized water and stirring at 300 rpm for 10 minutes; adding nano-titanium dioxide and anhydrous ethanol and ultrasonically dispersing at 300 W and 40 kHz for 20 minutes; adding sodium-based bentonite and stirring at 300 rpm for 30 minutes; heating in a water bath at 40-50°C; adding methyltrimethoxysilane and stirring at 300 rpm for 20 minutes to obtain a mixture; drying the mixture by forced air at 105°C for 30 minutes; and pulverizing the dried mixture to 325 mesh to obtain the modified organobentonite.

[0017] Industrial grade sodium bentonite, purity ≥95%, particle size 325 mesh, montmorillonite content ≥85%.

[0018] Nano-titanium dioxide is anatase with a particle size of 20nm. It is hydrophilic and can be embedded in the interlayer of bentonite and attached to its surface, forming an inorganic hybrid reinforcement structure with bentonite, thereby improving the rigidity and structural strength of bentonite itself.

[0019] Methyltrimethoxysilane is an industrial grade material with a purity of ≥98%. It is a hydrophobic end-capping modifier for bentonite. It can undergo a condensation reaction with the hydroxyl groups on the surface of bentonite, completely eliminating its hydrophilic groups and significantly improving the hydrophobicity and oil solubility of bentonite.

[0020] Intercalating agents enter the interlayer voids of sodium-based bentonite through ion exchange, significantly widening the interlayer spacing of bentonite to 6-8 nm, while forming a stable hydrophobic organic layer in the interlayer, thus improving the high-temperature structural stability of bentonite.

[0021] Furthermore, the intercalating agent is a mixture of hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride in a mass ratio of 7:3.

[0022] Hexadecyltrimethylammonium bromide has a long chain.

[0023] Dodecyl dimethyl benzyl ammonium chloride is a short-chain compound.

[0024] Furthermore, the mass ratio of the deionized water, intercalating agent, nano-titanium dioxide, anhydrous ethanol, sodium bentonite, and methyltrimethoxysilane is 3.5:0.16:0.035:0.012:1:0.025.

[0025] Further, the preparation of the modified bisphenol A epoxy resin includes the following steps: mixing and stirring bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phosphomolybdate, composite material, and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine at a speed of 300 rpm and a temperature of 90-100°C for 30 minutes; introducing nitrogen gas; adding nitrile rubber and stirring at a speed of 300 rpm for 15 minutes; adding a catalyst and stirring at a speed of 300 rpm for 10 minutes; heating to 130-140°C at a heating rate of 5°C / min; stirring at a constant temperature for 1.5 hours; stopping heating; setting the speed to 200 rpm; and allowing the temperature to cool naturally to below 40°C to obtain the modified bisphenol A epoxy resin.

[0026] The bisphenol A epoxy resin is industrial grade, with an epoxy value of 0.51 eq / 100g, a solid content of ≥99%, and a moisture content of ≤0.1%.

[0027] The terminal carboxyl naphthalene anhydride is of industrial grade with a purity of ≥98% and a water content of ≤0.1%. It can undergo block copolymerization with the secondary hydroxyl groups of bisphenol A epoxy resin, introducing a conjugated naphthalene anhydride aromatic ring structure into the main chain of the resin molecule, which greatly improves the thermal stability of the resin molecule chain.

[0028] Nitrile rubber is of industrial grade, with a branching degree ≥0.8, molecular weight 5000-6000, terminal amino content ≥1.8mmol / g, and moisture content ≤0.1%. It undergoes a ring-opening reaction with the epoxy groups of epoxy resin through multi-point grafting, forming three-dimensional hyperbranched elastic microdomains on the side chains of the resin molecules. This improves the problem of high brittleness of epoxy resin after high-temperature curing at the molecular level, and enhances the resin's impact resistance and crack resistance.

[0029] Phosphate molybdate is of industrial grade, with a purity ≥95% and a moisture content ≤0.1%. It can undergo a copolymerization reaction with terminal carboxyl naphthalene anhydride, introducing phosphorus-molybdenum anti-corrosion active sites into the resin molecular chain. This allows the epoxy resin itself to possess the ability to passivate and prevent corrosion of steel casings, breaking the limitation of traditional resins that rely solely on external anti-corrosion additives.

[0030] Under the action of a composite catalyst, the composite material can complete hydrolysis and condensation reactions within the resin system, generating magnesium borate nanocrystals in situ. One end of the whisker forms a chemical bond with the resin molecular chain, constructing a three-dimensional reinforcing network inside the resin, which significantly improves the compressive strength and impermeability of the resin after curing.

[0031] Furthermore, the composite material is composed of triethyl borate and magnesium oxide mixed in a mass ratio of 1:1; The catalyst is composed of triphenylphosphine and imidazoline derivatives in a mass ratio of 3:1.

[0032] The imidazoline derivatives are one of 2-ethyl-4-methylimidazoline, 1-benzyl-2-methylimidazoline, and 1-aminopropyl-2-hydroxyethylimidazoline.

[0033] 2-Ethyl-4-methylimidazoline is of industrial grade with a purity of ≥98%.

[0034] 1-Benzyl-2-methylimidazoline is of industrial grade with a purity of ≥97%.

[0035] 1-Aminopropyl-2-hydroxyethylimidazoline is industrial grade with a purity ≥97%.

[0036] Triethyl borate is industrial grade with a moisture content of ≤0.1%.

[0037] The magnesium oxide is industrial grade, with a particle size of 200 mesh and a moisture content of ≤0.1%.

[0038] Furthermore, the mass ratio of the bisphenol A epoxy resin, terminal carboxyl naphthalene anhydride, phosphomolybdate, composite material, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, nitrile rubber, and catalyst is 100:13:1.5:3.5:0.15:9:0.5.

[0039] Secondly, the present invention provides a method for preparing a resin-based anti-corrosion and plugging agent for plugging leaks in oil and water well casings, the method comprising the following steps: S1. Add modified bisphenol A epoxy resin to the reactor and stir. Set the speed to 300 rpm and the temperature to 40℃. Stir for 10 minutes. Add amino-terminated butadiene nitrile rubber and stir. Set the speed to 300 rpm and stir for 20 minutes. Add modified organic bentonite, plugging filler and anti-corrosion additive and stir. Set the speed to 300 rpm and stir for 30 minutes. Reduce the speed to 200 rpm and stir for 5 minutes to obtain component A. S2. Mix 4,4'-diaminodiphenyl sulfone and 2-methylimidazole and stir at 200 rpm for 10 minutes. Add γ-glycidyl etheroxypropyltrimethoxysilane and stir at 200 rpm for 20 minutes to obtain component B. S3. Add component A to the reactor, set the temperature to 70-80℃, add component B and stir, set the speed to 400-500 rpm, stir for 10-12 minutes to obtain resin-based anti-corrosion and plugging agent for oil and water well casing leakage. The mass ratio of component A to component B is 4:1.

[0040] The present invention has the following beneficial effects: 1. In this invention, modified bisphenol A epoxy resin is added. The naphthalene anhydride aromatic ring structure in its molecular chain significantly improves high-temperature thermal stability, enabling it to withstand downhole temperatures of 200-250℃ for a long time and 300℃ for a short time without aging or pulverization. The hyperbranched elastic graft segments can alleviate the brittleness after high-temperature curing and adapt to the stress impact caused by downhole temperature and pressure fluctuations. The in-situ grown magnesium borate whiskers are chemically combined with the molecular chain to form an internal reinforcing network, improving the compressive strength and impermeability. At the same time, the phosphorus-molybdenum heteroatom anti-corrosion sites on the molecular chain endow the resin with anti-corrosion capabilities, forming a double protection with the added anti-corrosion additives. It also has excellent compatibility with various fillers and curing agents in the plugging agent. After cross-linking, it can form a dense three-dimensional network structure, providing basic bonding and structural support for plugging and anti-corrosion.

[0041] 2. In this invention, modified organic bentonite is added. After being modified by quaternary ammonium salt intercalation, nano-hybridization, and hydrophobic silane end-capping, the interlayer spacing is significantly increased. The layered structure remains intact without collapse at 250°C, and the thixotropic properties do not significantly decrease. A high thixotropic index can be achieved with a low dosage, giving the plugging agent the characteristics of low shear flow and high shear thickness. It is easy to pump during construction and thickens rapidly after standing to prevent downhole flow. Its hydrophobicity and oil solubility are excellent, and it has high compatibility with modified bisphenol A epoxy resin. It can be uniformly dispersed without agglomeration with low-speed stirring. Moreover, the nano-hybrid structure can form a synergistic reinforcing network with the in-situ whiskers in the modified bisphenol A epoxy resin, which helps to improve the compressive strength and impermeability of the solidified body. At the same time, the hydrophobic end-capping characteristics further improve the system's water resistance and mineralization resistance.

[0042] 3. In this invention, an anti-corrosion additive is added. The zinc powder has a large specific surface area and stable anti-corrosion activity at 250℃. It preferentially undergoes electrochemical corrosion with corrosive media, protecting the steel casing body through self-consumption. Simultaneously, its corrosion reaction products create favorable conditions for the passivation reaction of zinc molybdate, promoting the rapid formation of a dense and stable inorganic passivation film on the steel casing surface. This completely blocks direct contact between corrosive media such as H2S, CO2, and high-mineralization formation water and the steel casing from a physical perspective. The synergy of these two additives also enables the self-repair of the passivation film. When minor damage occurs to the passivation film, the continuous sacrifice of zinc powder... Corrosion resistant materials can promptly repair damaged areas, preventing corrosive media from entering through the damaged points and significantly extending the corrosion protection period of steel casing. Furthermore, in harsh downhole conditions with ultra-high temperatures (200-250℃) and high mineralization, neither material dissolves or decomposes, exhibiting stable chemical properties and no reduction in anti-corrosion effect. Simultaneously, it forms a dual anti-corrosion system on the surface and within the matrix with the phosphorus-molybdenum anti-corrosion sites of the modified bisphenol A epoxy resin. Both materials are also uniformly dispersed in the resin system and firmly bonded to other components, without affecting the core properties of the plugging agent, such as its consolidation strength, impermeability, and adhesion. This perfectly balances the dual engineering requirements of corrosion protection and casing plugging. Detailed Implementation

[0043] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0044] It should be noted that all raw materials used in the following experiments are commercially available.

[0045] Example 1: Resin-based anti-corrosion and plugging agent for oil and water well casing leakage. The resin-based anti-corrosion and plugging agent for oil and water well casing leakage includes the following raw materials: 34 parts modified bisphenol A epoxy resin, 3 parts amino-terminated nitrile rubber, 43 parts plugging filler, 2 parts anti-corrosion additive, 1.5 parts modified organobentonite, 18 parts 4,4'-diaminodiphenyl sulfone, 0.1 parts 2-methylimidazole and 1 part γ-glycidyl etheroxypropyltrimethoxysilane.

[0046] The corrosion inhibitor is a mixture of zinc powder and zinc molybdate in a mass ratio of 2:1.

[0047] The sealing filler is made of quartz sand, barite powder and mica powder mixed in a mass ratio of 2:1:1.

[0048] The preparation of modified organobentonite includes the following steps: adding the intercalating agent to deionized water and stirring at 300 rpm for 10 minutes; adding nano-titanium dioxide and anhydrous ethanol and ultrasonically dispersing at 300 W and 40 kHz for 20 minutes; adding sodium-based bentonite and stirring at 300 rpm for 30 minutes; heating in a water bath at 40°C; adding methyltrimethoxysilane and stirring at 300 rpm for 20 minutes to obtain a mixture; drying the mixture by forced air at 105°C for 30 minutes; and pulverizing the dried mixture to 325 mesh to obtain modified organobentonite.

[0049] The intercalating agent is a mixture of hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride in a mass ratio of 7:3.

[0050] The mass ratio of deionized water, intercalating agent, nano titanium dioxide, anhydrous ethanol, sodium bentonite, and methyltrimethoxysilane is 3.5:0.16:0.035:0.012:1:0.025.

[0051] The preparation of modified bisphenol A epoxy resin includes the following steps: bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phosphomolybdate, composite material, and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine are mixed and stirred at 300 rpm and 90°C for 30 minutes. Nitrogen gas is introduced, nitrile rubber is added and stirred at 300 rpm for 15 minutes. A catalyst is added and stirred at 300 rpm for 10 minutes. The temperature is then increased to 130°C at a rate of 5°C / min and stirred at a constant temperature for 1.5 hours. Heating is stopped, the temperature is allowed to cool naturally to below 40°C at 200 rpm to obtain the modified bisphenol A epoxy resin.

[0052] The composite material is made by mixing triethyl borate and magnesium oxide in a mass ratio of 1:1; The catalyst is a mixture of triphenylphosphine and imidazoline derivatives in a mass ratio of 3:1.

[0053] The mass ratio of bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phosphomolybdate, composite material, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, nitrile rubber, and catalyst is 100:13:1.5:3.5:0.15:9:0.5.

[0054] A method for preparing a resin-based anti-corrosion and plugging agent for plugging leaks in oil and water well casings, comprising the following steps: S1. Add modified bisphenol A epoxy resin to the reactor and stir. Set the speed to 300 rpm and the temperature to 40℃. Stir for 10 minutes. Add amino-terminated butadiene nitrile rubber and stir. Set the speed to 300 rpm and stir for 20 minutes. Add modified organic bentonite, plugging filler and anti-corrosion additive and stir. Set the speed to 300 rpm and stir for 30 minutes. Reduce the speed to 200 rpm and stir for 5 minutes to obtain component A. S2. Mix 4,4'-diaminodiphenyl sulfone and 2-methylimidazole and stir at 200 rpm for 10 minutes. Add γ-glycidyl etheroxypropyltrimethoxysilane and stir at 200 rpm for 20 minutes to obtain component B. S3. Add component A to the reactor, set the temperature to 70℃, add component B and stir, set the speed to 400 rpm, stir for 10 minutes to obtain resin-based anti-corrosion and plugging agent for oil and water well casing. The mass ratio of component A to component B is 4:1.

[0055] Example 2: Resin-based anti-corrosion and plugging agent for oil and water well casing leakage. The resin-based anti-corrosion and plugging agent for oil and water well casing leakage includes the following raw materials: 35 parts modified bisphenol A epoxy resin, 3.5 parts amino-terminated nitrile rubber, 44 parts plugging filler, 2.5 parts anti-corrosion additive, 1.75 parts modified organobentonite, 19 parts 4,4'-diaminodiphenyl sulfone, 0.15 parts 2-methylimidazole and 1.25 parts γ-glycidyl etheroxypropyltrimethoxysilane.

[0056] The corrosion inhibitor is a mixture of zinc powder and zinc molybdate in a mass ratio of 2:1.

[0057] The sealing filler is made of quartz sand, barite powder and mica powder mixed in a mass ratio of 2:1:1.

[0058] The preparation of modified organobentonite includes the following steps: adding an intercalating agent to deionized water and stirring at 300 rpm for 10 minutes; adding nano-titanium dioxide and anhydrous ethanol and ultrasonically dispersing at 300 W and 40 kHz for 20 minutes; adding sodium-based bentonite and stirring at 300 rpm for 30 minutes; heating in a water bath at 45°C; adding methyltrimethoxysilane and stirring at 300 rpm for 20 minutes to obtain a mixture; drying the mixture by forced air at 105°C for 30 minutes; and pulverizing the dried mixture to 325 mesh to obtain modified organobentonite.

[0059] The intercalating agent is a mixture of hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride in a mass ratio of 7:3.

[0060] The mass ratio of deionized water, intercalating agent, nano titanium dioxide, anhydrous ethanol, sodium bentonite, and methyltrimethoxysilane is 3.5:0.16:0.035:0.012:1:0.025.

[0061] The preparation of modified bisphenol A epoxy resin includes the following steps: bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phospholipid molybdate, composite material, and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine are mixed and stirred at 300 rpm and 95°C for 30 minutes. Nitrogen gas is introduced, nitrile rubber is added and stirred at 300 rpm for 15 minutes. A catalyst is added and stirred at 300 rpm for 10 minutes. The temperature is then increased to 135°C at a rate of 5°C / min and stirred at a constant temperature for 1.5 hours. Heating is stopped, the temperature is allowed to cool naturally to below 40°C at 200 rpm to obtain the modified bisphenol A epoxy resin.

[0062] The composite material is made by mixing triethyl borate and magnesium oxide in a mass ratio of 1:1; The catalyst is a mixture of triphenylphosphine and imidazoline derivatives in a mass ratio of 3:1.

[0063] The mass ratio of bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phosphomolybdate, composite material, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, nitrile rubber, and catalyst is 100:13:1.5:3.5:0.15:9:0.5.

[0064] A method for preparing a resin-based anti-corrosion and plugging agent for plugging leaks in oil and water well casings, comprising the following steps: S1. Add modified bisphenol A epoxy resin to the reactor and stir. Set the speed to 300 rpm and the temperature to 40℃. Stir for 10 minutes. Add amino-terminated butadiene nitrile rubber and stir. Set the speed to 300 rpm and stir for 20 minutes. Add modified organic bentonite, plugging filler and anti-corrosion additive and stir. Set the speed to 300 rpm and stir for 30 minutes. Reduce the speed to 200 rpm and stir for 5 minutes to obtain component A. S2. Mix 4,4'-diaminodiphenyl sulfone and 2-methylimidazole and stir at 200 rpm for 10 minutes. Add γ-glycidyl etheroxypropyltrimethoxysilane and stir at 200 rpm for 20 minutes to obtain component B. S3. Add component A to the reactor, set the temperature to 75℃, add component B and stir, set the speed to 450 rpm, stir for 11 minutes to obtain resin-based anti-corrosion and plugging agent for oil and water well casing leakage plugging. The mass ratio of component A to component B is 4:1.

[0065] Example 3: Resin-based anti-corrosion and plugging agent for oil and water well casing leakage. The resin-based anti-corrosion and plugging agent for oil and water well casing leakage includes the following raw materials: 36 parts modified bisphenol A epoxy resin, 4 parts amino-terminated nitrile rubber, 45 parts plugging filler, 3 parts anti-corrosion additive, 2 parts modified organobentonite, 20 parts 4,4'-diaminodiphenyl sulfone, 0.2 parts 2-methylimidazole and 1.5 parts γ-glycidyl etheroxypropyltrimethoxysilane.

[0066] The corrosion inhibitor is a mixture of zinc powder and zinc molybdate in a mass ratio of 2:1.

[0067] The sealing filler is made of quartz sand, barite powder and mica powder mixed in a mass ratio of 2:1:1.

[0068] The preparation of modified organobentonite includes the following steps: adding an intercalating agent to deionized water and stirring at 300 rpm for 10 minutes; adding nano-titanium dioxide and anhydrous ethanol and ultrasonically dispersing at 300 W and 40 kHz for 20 minutes; adding sodium-based bentonite and stirring at 300 rpm for 30 minutes; heating in a water bath at 50°C; adding methyltrimethoxysilane and stirring at 300 rpm for 20 minutes to obtain a mixture; drying the mixture by forced air at 105°C for 30 minutes; and pulverizing the dried mixture to 325 mesh to obtain modified organobentonite.

[0069] The intercalating agent is a mixture of hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride in a mass ratio of 7:3.

[0070] The mass ratio of deionized water, intercalating agent, nano titanium dioxide, anhydrous ethanol, sodium bentonite, and methyltrimethoxysilane is 3.5:0.16:0.035:0.012:1:0.025.

[0071] The preparation of modified bisphenol A epoxy resin includes the following steps: bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phospholipid molybdate, composite material, and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine are mixed and stirred at 300 rpm and 100°C for 30 minutes. Nitrogen gas is introduced, nitrile rubber is added and stirred at 300 rpm for 15 minutes. A catalyst is added and stirred at 300 rpm for 10 minutes. The mixture is heated to 140°C at a heating rate of 5°C / min and stirred at a constant temperature for 1.5 hours. Heating is stopped, and the mixture is allowed to cool naturally to below 40°C at 200 rpm to obtain the modified bisphenol A epoxy resin.

[0072] The composite material is made by mixing triethyl borate and magnesium oxide in a mass ratio of 1:1; The catalyst is a mixture of triphenylphosphine and imidazoline derivatives in a mass ratio of 3:1.

[0073] The mass ratio of bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phosphomolybdate, composite material, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, nitrile rubber, and catalyst is 100:13:1.5:3.5:0.15:9:0.5.

[0074] A method for preparing a resin-based anti-corrosion and plugging agent for plugging leaks in oil and water well casings, comprising the following steps: S1. Add modified bisphenol A epoxy resin to the reactor and stir. Set the speed to 300 rpm and the temperature to 40℃. Stir for 10 minutes. Add amino-terminated butadiene nitrile rubber and stir. Set the speed to 300 rpm and stir for 20 minutes. Add modified organic bentonite, plugging filler and anti-corrosion additive and stir. Set the speed to 300 rpm and stir for 30 minutes. Reduce the speed to 200 rpm and stir for 5 minutes to obtain component A. S2. Mix 4,4'-diaminodiphenyl sulfone and 2-methylimidazole and stir at 200 rpm for 10 minutes. Add γ-glycidyl etheroxypropyltrimethoxysilane and stir at 200 rpm for 20 minutes to obtain component B. S3. Add component A to the reactor, set the temperature to 80℃, add component B and stir, set the speed to 500 rpm, stir for 12 minutes to obtain resin-based anti-corrosion and plugging agent for oil and water well casing leakage; The mass ratio of component A to component B is 4:1.

[0075] Comparative Example 1: The difference between this comparative example and Example 1 is that: Unmodified bisphenol A epoxy resin was used in this comparative example.

[0076] Comparative Example 2: The difference between this comparative example and Example 1 is that: Unmodified bentonite was used in this comparative example.

[0077] Comparative Example 3 differs from Example 1 in that: Quartz sand was not used as the plugging material in this comparative example.

[0078] Performance testing: The resin-based anti-corrosion and plugging agents for oil and water well casing prepared in Examples 1, 2, 3, 1, 2, and 3 were tested.

[0079] Performance testing: The relevant properties of the resin-based anti-corrosion and plugging agents for oil and water well casing and their preparation methods provided in Examples 1-3 and Comparative Examples 1-3 were tested respectively. The test data are recorded in Table 1 below: Table 1 - Test Data Record of Resin-Based Anti-corrosion and Leak-Plugging Agent for Oil and Water Well Casing Leakage Repair

[0080] Based on the above data, the following conclusions can be drawn: Among them, the compressive strength retention rate of resin-based anti-corrosion and plugging agents for oil and water well casings prepared according to the test methods in GB / T7141-2021 in Examples 1, 2, 3, Comparative Examples 1, 2, and 3 was tested after aging at 250°C for 168 hours. Thixotropic index tests were conducted on resin-based anti-corrosion and plugging agents for oil and water well casing prepared according to the test methods in GB / T2997-2000, namely, Examples 1, 2, 3, Comparative Examples 1, 2, and 3. The pressure-bearing strength of resin-based anti-corrosion and plugging agents for oil and water well casings prepared according to the test methods in GB / T10238-2015, Example 1, Example 2, Example 3, Comparative Example 1, Comparative Example 2 and Comparative Example 3, was tested after curing at 250℃.

[0081] Through the above demonstration, the present invention is significantly superior to the control group in terms of compressive strength retention rate, thixotropic index and compressive strength after curing at 250℃ for 168h, thus verifying the rationality of the preparation process.

[0082] In the description of this specification, references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0083] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The invention is limited only by the claims and their full scope and equivalents.

Claims

1. A resin-based anti-corrosion and leak-sealing agent for plugging leaks in oil and water well casings, characterized in that, The resin-based anti-corrosion and plugging agent for oil and water well casing leakage includes the following raw materials: 34-36 parts modified bisphenol A epoxy resin, 3-4 parts amino-terminated nitrile rubber, 43-45 parts plugging filler, 2-3 parts anti-corrosion additive, 1.5-2 parts modified organobentonite, 18-20 parts 4,4'-diaminodiphenyl sulfone, 0.1-0.2 parts 2-methylimidazole and 1-1.5 parts γ-glycidyl etheroxypropyltrimethoxysilane.

2. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 1, characterized in that, The corrosion inhibitor is composed of zinc powder and zinc molybdate mixed in a mass ratio of 2:

1.

3. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 1, characterized in that, The plugging filler is composed of quartz sand, barite powder and mica powder mixed in a mass ratio of 2:1:

1.

4. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 1, characterized in that, The preparation of the modified organobentonite includes the following steps: adding an intercalating agent to deionized water and stirring, adding nano-titanium dioxide and anhydrous ethanol and ultrasonically dispersing, adding sodium-based bentonite and stirring, adding methyltrimethoxysilane and stirring to obtain a mixture, drying the mixture by forced air, and pulverizing the dried mixture to obtain modified organobentonite.

5. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 4, characterized in that, The intercalating agent is a mixture of hexadecyltrimethylammonium bromide and dodecyldimethylbenzylammonium chloride in a mass ratio of 7:

3.

6. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 4, characterized in that, The mass ratio of the deionized water, intercalating agent, nano titanium dioxide, anhydrous ethanol, sodium bentonite, and methyltrimethoxysilane is 3.5:0.16:0.035:0.012:1:0.

025.

7. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 1, characterized in that, The preparation of the modified bisphenol A epoxy resin includes the following steps: mixing and stirring bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, molybdate phosphate, composite material and N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, setting the speed to 300 rpm, the temperature to 90-100℃, stirring for 30 minutes, introducing nitrogen gas, adding nitrile rubber and stirring, adding catalyst and stirring to obtain the modified bisphenol A epoxy resin.

8. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 7, characterized in that, The composite material is composed of triethyl borate and magnesium oxide mixed in a mass ratio of 1:

1. The catalyst is composed of triphenylphosphine and imidazoline derivatives in a mass ratio of 3:

1.

9. The resin-based anti-corrosion and plugging agent for oil and water well casing according to claim 7, characterized in that, The mass ratio of the bisphenol A epoxy resin, carboxyl-terminated naphthalene anhydride, phosphomolybdate, composite material, N,N'-bis-(3-(3,5-di-tert-butyl-4-hydroxyphenyl)propionyl)hexamethylenediamine, nitrile rubber, and catalyst is 100:13:1.5:3.5:0.15:9:0.

5.

10. The method for preparing the resin-based anti-corrosion and plugging agent for oil and water well casing according to any one of claims 1-9, characterized in that, The preparation method of the resin-based anti-corrosion and plugging agent for oil and water well casing leakage includes the following steps: S1. Add modified bisphenol A epoxy resin to a reactor and stir, add amino-terminated butadiene nitrile rubber and stir, add modified organic bentonite, plugging filler and anti-corrosion additive and stir to obtain component A; S2. Mix 4,4'-diaminodiphenyl sulfone and 2-methylimidazole, stir, add γ-glycidoxypropyltrimethoxysilane and stir to obtain component B; S3. Add component A to the reaction vessel, add component B and stir to obtain a resin-based anti-corrosion and plugging agent for oil and water well casing.

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