Temperature-resistant and salt-resistant ves composite diverting agent, and preparation method and application thereof

Abstract

The application discloses a kind of temperature-resistant salt-resistant VES composite diverting agent and its preparation method and application, belong to oil and gas field acidification stimulation technical field.The diverting agent includes the following components by weight parts: modified VES 5-15 parts, composite corrosion inhibitor 1-3 parts, intelligent response gel breaker 0.5-2 parts, nano stabilizer 0.1-0.5 parts, cosolvent 2-5 parts, the balance is water, the sum of weight parts of each component is 100 parts;Modified VES is prepared by radical polymerization from fluorine-containing heterocyclic monomer 20-40 parts, olefin sulfonate monomer 30-50 parts, functional crosslinking monomer 1-5 parts, initiator 0.3-1 part and solvent 50-80 parts.It has high temperature resistance, salt resistance, high-efficiency diverting capacity and environmental friendliness, to solve the performance attenuation of diverting agent under high temperature and high salt environment, low diverting efficiency, large reservoir damage and other technical problems.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas field acidification and production enhancement technology, specifically relating to a temperature-resistant and salt-resistant VES composite diverting agent, its preparation method, and its application. Background Technology

[0002] Acidizing is a key technology for improving the permeability of oil and gas reservoirs and increasing the productivity of oil and gas wells. Its core lies in guiding acid fluid evenly into each permeable segment of the reservoir using a diverting agent, achieving efficient dissolution of pores and fractures. As oil and gas exploration and development advances into deeper and ultra-deep formations, formation temperatures continue to rise (120-180℃) and salinity increases significantly (up to 25×10⁻⁶). 4 Traditional diverting agents face severe challenges. Among existing technologies, viscoelastic surfactant (VES) diverting agents are widely used due to their advantages such as no residue and easy backflow. However, conventional VES products have insufficient molecular structural stability, and their temperature resistance is usually limited to below 120℃. At high temperatures, the molecular chains are prone to thermal degradation, leading to severe viscosity decay. Some technologies improve temperature resistance by compounding different types of surfactants or adding stabilizers, but these suffer from poor component compatibility and low diverting efficiency. Other technologies use coupling modification or gel systems to improve stability, but these face drawbacks such as complex preparation processes, high costs, and insufficient controllability of gel breaking. Furthermore, existing diverting agents are prone to salting out in high-salinity environments, further exacerbating reservoir damage and affecting acidizing effects.

[0003] Therefore, developing a composite steering agent that combines high temperature resistance, salt resistance, high efficiency steering capability, and environmental friendliness has become an urgent need for the development of deep, high-temperature, and high-salinity oil and gas reservoirs. Summary of the Invention

[0004] In order to overcome the shortcomings of the prior art, the present invention aims to provide a temperature-resistant and salt-resistant VES composite steering agent, its preparation method and application, which combines high temperature resistance, salt resistance, high steering efficiency and environmental friendliness, in order to solve the technical problems of steering agent performance decay, low steering efficiency and great reservoir damage under high temperature and high salt environment.

[0005] To achieve the above objectives, the present invention employs the following technical solution: This invention provides a temperature-resistant and salt-resistant VES composite deflector, which, by weight, comprises the following components: 5-15 parts modified VES, 1-3 parts composite corrosion inhibitor, 0.5-2 parts smart responsive decolloid, 0.1-0.5 parts nano stabilizer, 2-5 parts cosolvent, and the balance being water, with the sum of the weight parts of each component being 100 parts. The modified VES is prepared by free radical polymerization of 20-40 parts of fluorinated heterocyclic monomer, 30-50 parts of olefin sulfonate monomer, 1-5 parts of functional crosslinking monomer, 0.3-1 parts of initiator and 50-80 parts of solvent.

[0006] In one embodiment, the fluorinated heterocyclic monomer is selected from at least one of fluoroimidazoline acrylate and trifluoromethylpyridinyl acrylamide; The olefin sulfonate monomer is a compound of sodium 2-acrylamido-2-methylpropanesulfonate and sodium p-styrenesulfonate, wherein the mass ratio of sodium 2-acrylamido-2-methylpropanesulfonate to sodium p-styrenesulfonate is 1:(0.5-2). The functional crosslinking monomer is selected from at least one of N,N'-methylenebisacrylamide and polyethylene glycol diacrylate; The initiator is a redox initiation system of ammonium persulfate and sodium bisulfite, and the mass ratio of ammonium persulfate to sodium bisulfite is 1:(0.3-0.5). The solvent is deionized water.

[0007] In one embodiment, the composite corrosion inhibitor is a compound of oleic acid imidazoline quaternary ammonium salt and inositol hexaphosphate, wherein the mass ratio of oleic acid imidazoline quaternary ammonium salt to inositol hexaphosphate is 2.5:1.

[0008] In one embodiment, the smart responsive decapsulator is a temperature / pH dual-responsive peroxide microcapsule with ammonium persulfate as the core material and polylactic acid-glycolic acid copolymer as the capsule wall material. The polylactic acid-glycolic acid copolymer has a molar mass ratio of lactic acid to glycolic acid of 75:25 and a molecular weight of 40,000.

[0009] In one embodiment, the preparation process of the temperature / pH dual-responsive peroxide microcapsules is as follows: An aqueous phase was prepared by dissolving ammonium persulfate in deionized water. An oil phase was prepared by dissolving polylactic acid-glycolic acid copolymer in dichloromethane; The aqueous phase is added to the oil phase and shear emulsified to form a W / O emulsion. The W / O emulsion was slowly dripped into a polyvinyl alcohol aqueous solution for curing, and then washed, centrifuged and vacuum dried to obtain ammonium persulfate microcapsule de-gelatinizer, namely temperature / pH dual-responsive peroxide microcapsules. The mass ratio of ammonium persulfate to deionized water was 1:5; the mass ratio of polylactic acid-glycolic acid copolymer to dichloromethane was 8:100; the mass ratio of W / O emulsion to polyvinyl alcohol aqueous solution was 1:4; the mass fraction of polyvinyl alcohol aqueous solution was 1%; and the curing time was 2 h.

[0010] In one embodiment, the nano-stabilizer is γ-aminopropyltriethoxysilane surface-modified nano-silica; The preparation method of the γ-aminopropyltriethoxysilane surface-modified nano-silica is as follows: Nano-silica was dispersed in an ethanol-water mixture, and then γ-aminopropyltriethoxysilane was added. The mixture was stirred and reacted, and then centrifuged, washed with ethanol and vacuum dried in sequence to obtain γ-aminopropyltriethoxysilane-modified nano-silica. The mass ratio of nano-silica to ethanol-water mixture was 1:10; the volume ratio of ethanol to water in the ethanol-water mixture was 9:1; the mass ratio of γ-aminopropyltriethoxysilane to nano-silica was 1.2:10; the stirring reaction was carried out at 60℃ for 3 hours.

[0011] In one embodiment, the cosolvent is a mixture of ethylene glycol monobutyl ether and isopropanol, wherein the mass ratio of the mixture of ethylene glycol monobutyl ether and isopropanol is 1:(1-2).

[0012] This invention also provides a method for preparing a temperature- and salt-resistant VES composite reversing agent, comprising the following steps: Fluorine-containing heterocyclic monomers, olefin sulfonate monomers, and functional crosslinking monomers were added to a solvent and stirred to dissolve. After purging with nitrogen to remove oxygen, an initiator was added, and the reaction was carried out at a constant temperature at a first set temperature. After the reaction was completed, precipitation, washing, and drying were carried out in sequence to obtain modified VES. Water and co-solvent are mixed evenly, and modified VES, composite corrosion inhibitor and nano stabilizer are added in sequence at a second set temperature. The mixture is stirred and dissolved, and then smart responsive degumming agent is added. The mixture is stirred at room temperature to obtain temperature-resistant and salt-resistant VES composite deflector.

[0013] In one embodiment, the first set temperature is 60-80°C, and the isothermal reaction time is 4-6 hours; the second set temperature is 40-50°C.

[0014] This invention also provides an application of a temperature- and salt-resistant VES composite diverting agent in acidizing operations of deep, high-temperature, and high-salinity oil and gas reservoirs. The temperature- and salt-resistant VES composite diverting agent is compounded with an acid solution to form a diverting acid. The mass fraction of the temperature- and salt-resistant VES composite diverting agent in the diverting acid is 3-10%. The acid solution is hydrochloric acid, fluoroboric acid, or terpineic acid. The terpineic acid is obtained by mixing hydrochloric acid and hydrofluoric acid at a volume ratio of 12:3. The diverting acid is suitable for temperatures of 120-180℃ and mineralization of 0-25×10⁻⁶. 4 Acidizing stimulation operations for deep, high-temperature, and high-salinity oil and gas reservoirs with a concentration of mg / L.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention provides a temperature- and salt-resistant VES composite diverting agent. This diverting agent, through molecular structure design and multi-component synergistic compounding, uses a novel modified viscoelastic surfactant (VES) as its core, combined with a composite corrosion inhibitor, a smart-response desiccant, a nano-stabilizer, and a co-solvent, forming a composite system that combines excellent high-temperature stability, salt resistance, diverting efficiency, and low reservoir damage. Specifically, the novel modified VES is copolymerized with a fluorinated heterocyclic monomer and an olefin sulfonate, introducing a rigid ring structure and salt-resistant functional groups. Combined with functional crosslinking monomers to optimize the molecular network, it can withstand high temperatures of 120-180℃ and salt resistance of 0-25×10⁻⁶. 4 This temperature- and salt-resistant VES composite diverting agent exhibits excellent high-temperature resistance. The modified VES is copolymerized with fluorinated heterocyclic monomers and olefin sulfonates, introducing a rigid ring structure and salt-resistant functional groups. Combined with the synergistic effect of nano-stabilizers, the composite diverting agent retains over 85% viscosity after 72 hours of isothermal aging at 120-180℃, significantly superior to existing products. Furthermore, it demonstrates outstanding salt resistance; the strongly polar sulfonate groups of the olefin sulfonate monomers effectively resist interference from high-mineralization ions, allowing the system to withstand mineralization up to 25 × 10⁻⁶ mg / L. 4 Formation water concentration of mg / L, with no salt precipitation, suitable for various high-salinity oil and gas reservoirs. High diversion efficiency; after gelation, viscosity can reach 100-150 mPa·s, with a plugging rate exceeding 90%, effectively sealing high-permeability layers and forcing acid to divert to low-permeability layers, achieving uniform acidizing and improving acidizing effects. Controllable and thorough gel breaking; the intelligent response gel breaker adopts a dual-response design of temperature / pH, allowing for precise control of gel breaking timing. After acidizing, the viscosity of the gel breaking solution is ≤3 mPa·s, with no residue, high flowback rate, and minimal reservoir damage. Simultaneously, excellent corrosion inhibition; the composite corrosion inhibitor, through synergistic action, effectively inhibits acid corrosion of downhole tubing even under high-temperature conditions, with a corrosion inhibition rate ≤0.05 mm / a, meeting on-site construction requirements.

[0016] This invention solves the problems of existing diverting agents such as easy degradation, incomplete gel breaking, and low diverting efficiency under high temperature and high salinity environments. The preparation process is simple, the reaction conditions are mild, and it is environmentally friendly. It is suitable for acidizing and transforming deep high temperature sandstone, carbonate rocks, and unconventional oil and gas reservoirs, and has broad application prospects.

[0017] The preparation process of this temperature- and salt-resistant VES composite deflector is simple. The polymerization and compounding are carried out under normal pressure, the reaction conditions are mild, no special high-end equipment is required, and the raw materials are widely available and the cost is controllable, which facilitates large-scale industrial production. At the same time, it has excellent environmental protection. The composite corrosion inhibitor and co-solvent are both made of environmentally friendly materials with low biotoxicity, which meets the requirements of green energy development and can effectively reduce the pollution of the environment caused by the acidification process. Detailed Implementation

[0018] To enable those skilled in the art to understand the features and effects of the present invention, the terms and expressions used in the specification and claims are explained and defined in general below. Unless otherwise specified, all technical and scientific terms used herein have the ordinary meaning understood by those skilled in the art regarding the present invention, and in case of conflict, the definitions in this specification shall prevail.

[0019] The theories or mechanisms described and disclosed herein, whether right or wrong, should not in any way limit the scope of the invention, that is, the contents of the invention can be implemented without being limited by any particular theory or mechanism.

[0020] In this document, all features defined by numerical ranges or percentage ranges, such as numerical values, quantities, contents, and concentrations, are for the sake of brevity and convenience only. Accordingly, descriptions of numerical ranges or percentage ranges should be considered as covering and specifically disclosing all possible sub-ranges and individual numerical values ​​(including integers and fractions) within those ranges.

[0021] In this article, unless otherwise specified, “contains,” “includes,” “containing,” “has,” or similar terms cover the meanings of “composed of” and “mainly composed of,” for example, “A contains a” covers the meanings of “A contains a and others” and “A contains only a.”

[0022] For the sake of brevity, not all possible combinations of the technical features in each implementation scheme or embodiment are described herein. Therefore, as long as there is no contradiction in the combination of these technical features, the technical features in each implementation scheme or embodiment can be combined arbitrarily, and all possible combinations should be considered within the scope of this specification.

[0023] This invention provides a temperature- and salt-resistant VES composite deflector, its preparation method, and its application.

[0024] On the one hand, a temperature-resistant and salt-resistant VES composite deflector is provided, which, by weight, includes: 5-15 parts of modified VES, 1-3 parts of composite corrosion inhibitor, 0.5-2 parts of smart responsive desiccant, 0.1-0.5 parts of nano stabilizer, 2-5 parts of cosolvent, and the balance being water, with the sum of the weight parts of each component being 100 parts.

[0025] Preferably, the modified VES is prepared by free radical polymerization from 20-40 parts of fluorinated heterocyclic monomer, 30-50 parts of olefin sulfonate monomer, 1-5 parts of functional crosslinking monomer, 0.3-1 parts of initiator and 50-80 parts of solvent.

[0026] Preferably, the fluorinated heterocyclic monomer is selected from at least one of fluoroimidazoline acrylate and trifluoromethylpyridinyl acrylamide. The heterocyclic structure of fluoroimidazoline acrylate and the presence of fluorine atoms significantly enhance molecular thermal stability, while the rigid ring structure of trifluoromethylpyridinyl acrylamide inhibits molecular chain creep at high temperatures. The two monomers, used alone or in combination, can achieve precise control of temperature resistance.

[0027] Preferably, the olefinic sulfonate monomer is a compound of sodium 2-acrylamido-2-methylpropanesulfonate and sodium p-styrenesulfonate, with a mass ratio of 1:(0.5-2). The strongly polar sulfonate group of sodium 2-acrylamido-2-methylpropanesulfonate enhances salt resistance, while sodium p-styrenesulfonate optimizes the hydrophilic-hydrophobic balance of the molecular chain. The synergistic effect of these two compounds allows VES to maintain good solubility and viscoelastic properties in high-mineralization environments.

[0028] Preferably, the functional crosslinking monomer is selected from at least one of N,N'-methylenebisacrylamide and polyethylene glycol diacrylate. N,N'-methylenebisacrylamide can construct a dense molecular network, while polyethylene glycol diacrylate can impart moderate flexibility to the molecular chains; when used in combination, they can balance the viscoelastic properties and debonding performance of the system.

[0029] Preferably, the initiator is a redox initiation system of ammonium persulfate and sodium bisulfite, with a mass ratio of 1:(0.3-0.5). This system has mild reaction conditions and can efficiently initiate polymerization reactions at 60-80℃, precisely control molecular weight distribution, and avoid molecular chain degradation caused by high-temperature initiation.

[0030] Preferably, the composite corrosion inhibitor is a compound of oleic acid-based imidazoline quaternary ammonium salt and inositol hexaphosphate, with a compound mass ratio of 2.5:1.

[0031] Among them, oleic acid imidazoline quaternary ammonium salt can form a dense adsorption film on the metal surface, and inositol hexaphosphate enhances the corrosion inhibition effect by chelating metal ions. The synergistic effect of the two can still maintain excellent corrosion inhibition performance at high temperatures of 120-180℃, with a corrosion inhibition rate ≤0.05mm / a.

[0032] Preferably, the intelligent responsive breaker is a temperature / pH dual-responsive peroxide microcapsule with ammonium persulfate as the core material and polylactic acid-glycolic acid copolymer as the capsule wall material. The molar ratio of lactic acid to glycolic acid in the polylactic acid-glycolic acid copolymer is 75:25, and the molecular weight is 40,000. Under the dual stimulation of acidification temperature (120-180℃) and pH increase (≥2) after acid consumption, the wall material degrades and releases the breaker, achieving precise and controllable timing of breaker release. The viscosity of the breaker solution is ≤3 mPa·s, making it easy to return without residue.

[0033] The preparation process of the temperature / pH dual-responsive peroxide microcapsules described above is as follows: Dissolve 10 parts of ammonium persulfate in 50 parts of deionized water to form the aqueous phase; Dissolve 8 parts of PLGA (75:25, Mw 40000) in 100 parts of dichloromethane as the oil phase; The aqueous phase was added to the oil phase and emulsified under high-speed shear for 10 min to form a W / O emulsion. Then, 4 parts of 1% polyvinyl alcohol aqueous solution were slowly added dropwise to 1 part of the W / O emulsion. After curing for 2 h, the mixture was washed, centrifuged, and vacuum dried to obtain ammonium persulfate microcapsule de-gelling agent.

[0034] Preferably, the nano stabilizer is surface-modified nano silica, and the modifier is γ-aminopropyltriethoxysilane.

[0035] The preparation method of the γ-aminopropyltriethoxysilane surface-modified nano-silica is as follows: Take 10 parts of nano-SiO2 and disperse it in 100 parts of ethanol-water (9:1) mixture; 1.2 parts of γ-aminopropyltriethoxysilane were added, and the mixture was stirred at 60°C for 3 h. The mixture was then centrifuged, washed with ethanol, and dried under vacuum at 80°C to obtain modified nano-SiO2.

[0036] The modified nano-silica can be chemically bonded and adsorbed onto the surface of VES molecules, inhibiting the thermal motion of molecular chains at high temperatures, further improving the high-temperature stability of the system, and achieving a viscosity retention rate of over 85%.

[0037] Preferably, the co-solvent is a mixture of ethylene glycol monobutyl ether and isopropanol in a mass ratio of 1:(1-2). Ethylene glycol monobutyl ether improves the compatibility of fluorinated monomers with the aqueous phase, while isopropanol accelerates the dissolution of VES. The synergistic effect of these two compounds ensures a homogeneous and stable system, preventing stratification and flocculation.

[0038] Another aspect of this invention discloses a method for preparing the above-mentioned temperature-resistant and salt-resistant VES composite deflector, comprising the following steps: (1) Preparation of modified VES: Take 20-40 parts by weight of fluorinated heterocyclic monomer, 30-50 parts by weight of olefin sulfonate monomer and 1-5 parts by weight of functional crosslinking monomer, add 50-80 parts by weight of solvent deionized water and stir to dissolve. After purging with nitrogen gas to remove oxygen for 30 minutes, add 0.3-1 parts by weight of initiator, heat to 60-80℃ and react at a constant temperature for 4-6 hours. After the reaction is completed, pour the product into acetone to precipitate, filter and wash with ethanol 3 times, and dry under vacuum at 60℃ for 8 hours to obtain modified VES.

[0039] (2) Compounding of composite diverting agent: Take the amount of water and co-solvent in the formula and mix them evenly. Add the modified VES, composite corrosion inhibitor and nano stabilizer in sequence at 40-50℃. Stir for 30-60 minutes until completely dissolved. Finally, add the smart response degumming agent and stir at room temperature for 15-20 minutes to obtain a uniform and stable temperature-resistant and salt-resistant VES composite diverting agent.

[0040] Preferably, the temperature of the polymerization reaction in step (1) is controlled at 60-80°C. This temperature range can balance the reaction rate and product stability, and avoid incomplete reaction caused by low temperature or molecular chain degradation caused by high temperature.

[0041] Preferably, the mixing temperature in step (2) is 40-50℃ and the mixing time is 30-60 minutes, which can ensure that each component is fully dissolved and dispersed to form a uniform and stable composite system.

[0042] In another aspect, this invention provides the application of the above-mentioned temperature-resistant and salt-resistant VES composite diverting agent in acidizing operations of deep, high-temperature, and high-salinity oil and gas reservoirs.

[0043] The temperature- and salt-resistant VES composite reversing agent is compounded with hydrochloric acid, oxalic acid, or fluoroboric acid to form a reversing acid. The mass fraction of the reversing agent in the reversing acid is 3-10%, and it is suitable for temperatures of 120-180℃ and mineralization of 0-25×10⁻⁶. 4 The acidification operation of the oil and gas reservoir is carried out at a concentration of mg / L, wherein the acid is obtained by mixing hydrochloric acid and hydrofluoric acid at a volume ratio of 12:3.

[0044] Specifically, the applications of the aforementioned temperature- and salt-resistant VES composite steering agent are as follows: The temperature- and salt-resistant VES composite diverting agent is mixed with hydrochloric acid, arginine, or fluoroboric acid at a mass fraction of 3-10% and stirred evenly to form a diverting acid. This diverting acid is injected into the target oil and gas reservoir. During the reaction process with the formation temperature and the acid, VES molecules form a viscoelastic gel, blocking high-permeability layers and forcing the acid to divert to low-permeability layers, achieving uniform acidification. After acidification, a breaker triggers gel breaking under the dual stimulation of temperature and pH, facilitating the flowback of the broken fluid and reducing reservoir damage. This diverting acid is suitable for temperatures of 120-180℃ and salinity of 0-25×10⁻⁶. 4 Acidizing stimulation of deep, high-temperature, and high-salinity oil and gas reservoirs with a concentration of mg / L can effectively improve oil and gas recovery rates.

[0045] The present invention will be further illustrated below with reference to specific embodiments. It should be understood that these embodiments are for illustrative purposes only and are not intended to limit the scope of the invention. Furthermore, it should be understood that after reading the teachings of this invention, those skilled in the art can make various alterations or modifications to the invention, and these equivalent forms also fall within the scope defined by the appended claims.

[0046] The following examples use instruments and equipment conventional in the art. Experimental methods in the following examples, unless otherwise specified, are generally performed under conventional conditions or as recommended by the manufacturer. All raw materials used in the following examples are conventional commercially available products with specifications conventional in the art. In this specification and the following examples, unless otherwise specified, "%" refers to weight percentage, "parts" refers to parts by weight, and "ratio" refers to weight proportion.

[0047] Example 1 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: 20 parts of fluoroimidazoline acrylate, 30 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 15 parts of sodium p-styrenesulfonate, and 1 part of N,N'-methylenebisacrylamide were dissolved in 50 parts of deionized water by stirring. The mixture was then purged with nitrogen for 30 minutes to remove oxygen. 0.3 parts of ammonium persulfate and 0.09 parts of sodium bisulfite were added, and the mixture was heated to 60℃ and reacted for 6 hours. The product was precipitated with acetone, washed with ethanol, and dried under vacuum to obtain the novel modified VES.

[0048] S2. Formulation of composite steering agent: Take 85 parts of deionized water, 2 parts of ethylene glycol monobutyl ether, and 2 parts of isopropanol and mix them evenly. Add 5 parts of novel modified VES, 1 part of oleic acid-based imidazoline quaternary ammonium salt and inositol hexaphosphate compound corrosion inhibitor (compound ratio 2.5:1), and 0.1 parts of surface-modified nano silica at 40℃. Stir for 60 minutes. Finally, add 0.5 parts of smart responsive degumming agent and stir at room temperature for 20 minutes to obtain temperature-resistant and salt-resistant VES composite steering agent.

[0049] The intelligent responsive decapsulator is a temperature / pH dual-responsive peroxide microcapsule with ammonium persulfate as the core material and polylactic acid-glycolic acid copolymer as the capsule wall material, wherein the molar mass ratio of lactic acid to glycolic acid is 75:25 and the molecular weight is 40,000.

[0050] The preparation process of the temperature / pH dual-responsive peroxide microcapsules described above is as follows: Dissolve 10 parts of ammonium persulfate in 50 parts of deionized water to form the aqueous phase; Dissolve 8 parts of PLGA (75:25, Mw 40000) in 100 parts of dichloromethane as the oil phase; The aqueous phase was added to the oil phase and emulsified under high-speed shear for 10 min to form a W / O emulsion; Slowly drip in 4 parts of a 1% polyvinyl alcohol aqueous solution and cure for 2 hours; Washing, centrifugation, and vacuum drying yielded ammonium persulfate microcapsule de-gelatinizer.

[0051] The preparation method of the γ-aminopropyltriethoxysilane surface-modified nano-silica is as follows: Take 10 parts of nano-SiO2 and disperse it in 100 parts of ethanol-water (9:1) mixture; Add 1.2 parts of γ-aminopropyltriethoxysilane and stir at 60°C for 3 h. Modified nano-SiO2 was obtained by centrifugation, washing with ethanol, and vacuum drying at 80℃.

[0052] Performance testing: The diverting agent was mixed with 15% hydrochloric acid at a mass fraction of 3% to form diverting acid. After constant temperature aging at 120℃ and 0 mg / L mineralization for 72 hours, the viscosity retention rate was 88%; the gelation and plugging rate was 90%; after acidification, the viscosity of the broken gel was 2.9 mPa·s, and the corrosion inhibition rate was 0.05 mm / a.

[0053] Example 2 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: 30 parts of trifluoromethylpyridinylacrylamide, 25 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 25 parts of sodium p-styrenesulfonate, and 3 parts of polyethylene glycol diacrylate were added to 65 parts of deionized water and stirred to dissolve. Nitrogen gas was purged for 30 minutes to remove oxygen. Then, 0.6 parts of ammonium persulfate and 0.2 parts of sodium bisulfite were added, and the mixture was heated to 70°C and reacted for 5 hours. The product was precipitated with acetone, washed with ethanol, and dried under vacuum to obtain the novel modified VES.

[0054] S2. Formulation of composite steering agent: Take 80 parts of deionized water, 1.5 parts of ethylene glycol monobutyl ether, and 2.5 parts of isopropanol and mix them evenly. Add 10 parts of novel modified VES, 2 parts of oleic acid-based imidazoline quaternary ammonium salt and inositol hexaphosphate compound corrosion inhibitor (compound ratio 2.5:1), and 0.3 parts of surface-modified nano silica at 45°C. Stir for 45 minutes. Finally, add 1 part of smart responsive degumming agent and stir at room temperature for 18 minutes to obtain temperature-resistant and salt-resistant VES composite steering agent.

[0055] The composite corrosion inhibitor used in this embodiment is the same as that in Example 1.

[0056] The preparation methods of the smart responsive degumming agent and γ-aminopropyltriethoxysilane surface-modified nano-silica used in this embodiment are the same as those in Example 1.

[0057] Performance testing: This diverting agent is mixed with 20% terrine at a mass fraction of 6% to form diverting acid. The mixture is tested at 150℃ and a mineralization of 12×10⁻⁶. 4 After 72 hours of constant temperature aging under mg / L conditions, the viscosity retention rate was 87%; the gelation and plugging rate was 92%; after acidification, the viscosity of the broken gel was 2.5 mPa·s, and the corrosion inhibition rate was 0.045 mm / a.

[0058] Example 3 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: 40 parts of fluoroimidazoline acrylate, 15 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 15 parts of sodium p-styrene sulfonate, and 5 parts of N,N'-methylenebisacrylamide and polyethylene glycol diacrylate composite functional crosslinking monomer (composite ratio 1:1) were added to 80 parts of deionized water and stirred to dissolve. Nitrogen gas was purged for 30 minutes to remove oxygen. Then, 1 part of ammonium persulfate and 0.5 parts of sodium bisulfite were added, and the mixture was heated to 80℃ and reacted for 4 hours. The product was precipitated with acetone, washed with ethanol, and vacuum dried to obtain novel modified VES.

[0059] S2. Formulation of composite steering agent: Take 75 parts of deionized water, 2.5 parts of ethylene glycol monobutyl ether, and 2.5 parts of isopropanol and mix them evenly. Add 15 parts of novel modified VES, 3 parts of oleic acid-based imidazoline quaternary ammonium salt and inositol hexaphosphate compound corrosion inhibitor (compound ratio 3:1), and 0.5 parts of surface-modified nano silica at 50℃. Stir for 30 minutes. Finally, add 2 parts of smart responsive degumming agent and stir at room temperature for 15 minutes to obtain temperature-resistant and salt-resistant VES composite steering agent.

[0060] The composite corrosion inhibitor used in this embodiment is the same as that in Example 1.

[0061] The preparation methods of the smart responsive degumming agent and γ-aminopropyltriethoxysilane surface-modified nano-silica used in this embodiment are the same as those in Example 1.

[0062] Performance testing: This diverting agent is mixed with 18% fluoroboric acid at a mass fraction of 10% to form a diverting acid. The solution is tested at 180℃ and a mineralization of 25 × 10⁻⁶. 4 After 72 hours of constant temperature aging under mg / L conditions, the viscosity retention rate was 85%; the gelation and plugging rate was 93%; after acidification, the viscosity of the broken gel was 2.3 mPa·s, and the corrosion inhibition rate was 0.04 mm / a.

[0063] Example 4 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: Take 25 parts of fluoroimidazoline acrylate, 15 parts of trifluoromethylpyridinyl acrylamide, 20 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 10 parts of sodium p-styrene sulfonate, and 2 parts of polyethylene glycol diacrylate, add them to 60 parts of deionized water and stir to dissolve. Purge with nitrogen for 30 minutes to remove oxygen. Add 0.5 parts of ammonium persulfate and 0.15 parts of sodium bisulfite. Heat to 65℃ and react for 5.5 hours. After post-treatment, the novel modified VES is obtained.

[0064] S2. Formulation of composite steering agent: Take 82 parts of deionized water, 2 parts of ethylene glycol monobutyl ether, and 2 parts of isopropanol and mix them evenly. Add 8 parts of novel modified VES, 1.5 parts of composite corrosion inhibitor, and 0.2 parts of nano stabilizer at 42℃ and stir for 50 minutes. Add 0.8 parts of smart responsive degumming agent and stir at room temperature for 19 minutes to obtain composite steering agent.

[0065] The composite corrosion inhibitor used in this embodiment is the same as that in Example 1.

[0066] The preparation methods of the smart responsive degumming agent and γ-aminopropyltriethoxysilane surface-modified nano-silica used in this embodiment are the same as those in Example 1.

[0067] Performance testing: Mixed with 16% hydrochloric acid at 4% by mass, at 130℃, with a mineralization of 5×10⁻⁶. 4 Under the condition of mg / L, the viscosity retention rate is 89%, the plugging rate is 91%, the viscosity of the rupture solution is 2.7 mPa·s, and the corrosion inhibition rate is 0.048 mm / a.

[0068] Example 5 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: 35 parts of trifluoromethylpyridinylacrylamide, 18 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 12 parts of sodium p-styrenesulfonate, and 4 parts of N,N'-methylenebisacrylamide were added to 70 parts of deionized water and stirred to dissolve. Nitrogen gas was purged for 30 minutes to remove oxygen. 0.8 parts of ammonium persulfate and 0.32 parts of sodium bisulfite were added. The mixture was heated to 75°C and reacted for 4.5 hours. After post-treatment, novel modified VES was obtained.

[0069] S2. Formulation of composite deflecting agent: Take 78 parts of deionized water, 1.8 parts of ethylene glycol monobutyl ether, and 2.2 parts of isopropanol and mix them evenly. Add 12 parts of novel modified VES, 2.5 parts of composite corrosion inhibitor, and 0.4 parts of nano stabilizer at 48℃ and stir for 35 minutes. Add 1.5 parts of smart responsive degumming agent and stir at room temperature for 16 minutes to obtain composite deflecting agent.

[0070] The composite corrosion inhibitor used in this embodiment is the same as that in Example 1.

[0071] The preparation methods of the smart responsive degumming agent and γ-aminopropyltriethoxysilane surface-modified nano-silica used in this embodiment are the same as those in Example 1.

[0072] Performance testing: Mixed with 22% arginine at 8% by mass, at 160℃, with a mineralization of 18×10⁻⁶. 4Under the condition of mg / L, the viscosity retention rate is 86%, the plugging rate is 92.5%, the viscosity of the rupture solution is 2.4 mPa·s, and the corrosion inhibition rate is 0.042 mm / a.

[0073] Example 6 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: Take 32 parts of fluoroimidazoline acrylate, 22 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 18 parts of sodium p-styrene sulfonate, and 2.5 parts of functional crosslinking monomer (N,N'-methylenebisacrylamide: polyethylene glycol diacrylate = 1:1), add them to 68 parts of deionized water and stir to dissolve. Purge with nitrogen for 30 minutes to remove oxygen. Add 0.7 parts of ammonium persulfate and 0.28 parts of sodium bisulfite. Heat to 72℃ and react for 5 hours. After post-treatment, obtain novel modified VES.

[0074] S2. Formulation of composite deflecting agent: Take 81 parts of deionized water, 1.6 parts of ethylene glycol monobutyl ether, and 2.4 parts of isopropanol and mix them evenly. Add 9 parts of novel modified VES, 1.8 parts of composite corrosion inhibitor, and 0.25 parts of nano stabilizer at 44℃ and stir for 48 minutes. Add 1.2 parts of smart responsive degumming agent and stir at room temperature for 17 minutes to obtain composite deflecting agent.

[0075] The composite corrosion inhibitor used in this embodiment is the same as that in Example 1.

[0076] The preparation methods of the smart responsive degumming agent and γ-aminopropyltriethoxysilane surface-modified nano-silica used in this embodiment are the same as those in Example 1.

[0077] Performance testing: Mixed with 17% fluoroboric acid at 5% by mass, at 140℃, with a mineralization of 8×10⁻⁶. 4 Under the condition of mg / L, the viscosity retention rate is 88.5%, the plugging rate is 91.5%, the viscosity of the rupture solution is 2.6 mPa·s, and the corrosion inhibition rate is 0.046 mm / a.

[0078] Example 7 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: 28 parts of trifluoromethylpyridinylacrylamide, 24 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 16 parts of sodium p-styrenesulfonate, and 3.5 parts of functional crosslinking monomer were added to 75 parts of deionized water and stirred to dissolve. Nitrogen gas was purged for 30 minutes to remove oxygen. 0.9 parts of ammonium persulfate and 0.45 parts of sodium bisulfite were added. The mixture was heated to 78℃ and reacted for 4.2 hours. After post-treatment, novel modified VES was obtained.

[0079] S2. Formulation of composite deflecting agent: Take 77 parts of deionized water, 2.2 parts of ethylene glycol monobutyl ether, and 2.8 parts of isopropanol and mix them evenly. Add 13 parts of novel modified VES, 2.2 parts of composite corrosion inhibitor, and 0.45 parts of nano stabilizer at 47℃, stir for 38 minutes, add 1.8 parts of smart responsive decolloid, and stir at room temperature for 15.5 minutes to obtain composite deflecting agent.

[0080] The composite corrosion inhibitor used in this embodiment is the same as that in Example 1.

[0081] The preparation methods of the smart responsive degumming agent and γ-aminopropyltriethoxysilane surface-modified nano-silica used in this embodiment are the same as those in Example 1.

[0082] Performance testing: Mixed with 19% hydrochloric acid at a mass fraction of 9%, at 170℃, with a mineralization of 22×10⁻⁶. 4 Under the condition of mg / L, the viscosity retention rate is 85.5%, the plugging rate is 93%, the viscosity of the rupture solution is 2.2 mPa·s, and the corrosion inhibition rate is 0.041 mm / a.

[0083] Example 8 This embodiment provides a method for preparing a temperature-resistant and salt-resistant VES composite deflector, including the following steps: S1. Preparation of novel modified VES: 22 parts of fluoroimidazoline acrylate, 18 parts of trifluoromethylpyridinyl acrylamide, 19 parts of sodium 2-acrylamido-2-methylpropanesulfonate, 11 parts of sodium p-styrenesulfonate, and 3 parts of functional crosslinking monomer were added to 62 parts of deionized water and stirred to dissolve. Nitrogen gas was purged for 30 minutes to remove oxygen. 0.6 parts of ammonium persulfate and 0.24 parts of sodium bisulfite were added. The mixture was heated to 68℃ and reacted for 5.2 hours. After post-treatment, novel modified VES was obtained.

[0084] S2. Formulation of composite deflecting agent: Take 83 parts of deionized water, 1.7 parts of ethylene glycol monobutyl ether, and 2.3 parts of isopropanol and mix them evenly. Add 7 parts of novel modified VES, 1.2 parts of composite corrosion inhibitor, and 0.15 parts of nano stabilizer at 43℃, stir for 55 minutes, add 0.6 parts of smart responsive degumming agent, and stir at room temperature for 18.5 minutes to obtain composite deflecting agent.

[0085] The composite corrosion inhibitor used in this embodiment is the same as that in Example 1.

[0086] The preparation methods of the smart responsive degumming agent and γ-aminopropyltriethoxysilane surface-modified nano-silica used in this embodiment are the same as those in Example 1.

[0087] Performance testing: Mixed with 21% arginine at 7% by mass, at 135℃, with a mineralization of 10×10⁻⁶. 4Under the condition of mg / L, the viscosity retention rate was 89.2%, the plugging rate was 90.8%, the viscosity of the rupture solution was 2.8 mPa·s, and the corrosion inhibition rate was 0.049 mm / a.

[0088] Comparative Example 1 (Baseline: Example 2 | Variable: VES replaced with conventional betaine) This comparative example provides a method for preparing a reversing agent. The difference from Example 2 is that conventional betaine-type VES (erucamide propyl betaine) is used to replace the modified VES of the present invention as the core component. The remaining components, proportions and preparation processes are exactly the same as in Example 2.

[0089] Performance testing: When mixed with 20% terrine at a mass fraction of 6% to form a diverting acid, it was tested at 150℃ with a mineralization of 12×10⁻⁶. 4 After 72 hours of constant-temperature aging under mg / L conditions, the viscosity retention rate was only 62%; the gelation and plugging rate was 76%; and the gelation was incomplete after acidification, with a gelation solution viscosity of 14.0 mPa. The corrosion inhibition rate is 0.11 mm / a.

[0090] The performance test results show that the diverting agent prepared in this comparative example is not as effective as that in Example 2. This is because the conventional betaine-based VES molecular structure does not contain fluorinated heterocyclic rigid units and strong salt sulfonate groups. The molecular chain is easily thermally degraded at high temperatures and easily salted out at high mineralization, resulting in low viscosity retention rate and poor diverting and blocking ability of the system. At the same time, its own debonding controllability is poor, and it cannot achieve complete debonding and backflow.

[0091] Comparative Example 2 (Baseline: Example 2 | Variable: No nano-stabilizer added) This comparative example provides a method for preparing a reversing agent. The difference from Example 2 is that no nano-stabilizer (γ-aminopropyltriethoxysilane-modified nano-silica) is added. The remaining components, proportions, and preparation process are exactly the same as in Example 2.

[0092] Performance testing: When mixed with 20% terrine at a mass fraction of 6% to form a diverting acid, it was tested at 150℃ with a mineralization of 12×10⁻⁶. 4 After 72 hours of constant-temperature aging under mg / L conditions, the viscosity retention rate was only 71%; the gelation and plugging rate was 83%; and the viscosity of the broken gel solution after acidification was 2.6 mPa. s, corrosion inhibition rate 0.045 mm / a.

[0093] The performance test results show that the diverting agent prepared in this comparative example is not as effective as that in Example 2. This is because the lack of steric hindrance and chemical bonding stabilization of the nano stabilizer makes it impossible to suppress the thermal motion and degradation of VES molecular chains at high temperatures, resulting in a decrease in the high-temperature stability of the system and a significant reduction in viscosity retention and blocking effect.

[0094] Comparative Example 3 (Baseline: Example 2 | Variable: No smart-response breaker added) This comparative example provides a method for preparing a reversing agent. The difference from Example 2 is that no smart-responsive de-gelling agent (temperature / pH dual-responsive peroxide microcapsules) is added. The remaining components, proportions, and preparation process are exactly the same as in Example 2.

[0095] Performance testing: When mixed with 20% terrine at a mass fraction of 6% to form a diverting acid, it was tested at 150℃ with a mineralization of 12×10⁻⁶. 4 After 72 hours of constant-temperature aging at mg / L, the viscosity retention rate was 86%; the gelation and plugging rate was 91%; and the gel could not be automatically broken after acidification, with a gel breaking solution viscosity of 13.5 mPa. s, corrosion inhibition rate 0.045 mm / a.

[0096] Performance testing results show that the diverting agent prepared in this comparative example is less effective than that in Example 2. This is because it lacks a temperature / pH dual-responsive breaker. After acidification, the system cannot be precisely broken down under specific stimuli, resulting in incomplete breaking down and residue residue, which can easily cause reservoir damage and flowback difficulties.

[0097] Comparative Example 4 (Baseline: Example 3 | Variable: only modified VES without fluorine heterocyclic monomers) This comparative example provides a method for preparing a reversing agent. The difference from Example 3 is that no fluorinated heterocyclic monomers are introduced in the preparation process of the modified VES. Only olefin sulfonate monomers and functional crosslinking monomers are polymerized. The remaining components, ratios and preparation processes are exactly the same as in Example 3.

[0098] Performance testing: When mixed with 18% fluoroboric acid at a mass fraction of 10% to form a reversible acid, it was tested at 180℃ with a mineralization of 25×10⁻⁶. 4 After 72 hours of constant-temperature aging under mg / L conditions, the viscosity retention rate was only 58%; the gelation and plugging rate was 75%; and the viscosity of the broken gel was 3.8 mPa. s, corrosion inhibition rate 0.10 mm / a.

[0099] The performance test results show that the diverting agent prepared in this comparative example is not as effective as that in Example 3. This is because the modified VES molecular chain lacks the rigid structure of fluorine heterocycles, resulting in a significant decrease in thermal stability. Under high temperature and high salt conditions, the viscosity decays rapidly, the diverting and blocking ability is significantly reduced, and the overall stability of the system deteriorates, with both corrosion inhibition and gel breaking effects decreasing simultaneously.

[0100] Comparative Example 5 (Baseline: Example 5 | Variable: Corrosion inhibitor only is a single imidazoline quaternary ammonium salt) This comparative example provides a method for preparing a deflecting agent. The difference from Example 5 is that the composite corrosion inhibitor uses a single oleic acid-based imidazoline quaternary ammonium salt and is not compounded with inositol hexaphosphate. The remaining components, ratios, and preparation processes are exactly the same as in Example 5.

[0101] Performance testing: Mixed with 22% arginine at 8% by mass, at 160℃ and a mineralization of 18×10⁻⁶. 4 Under the condition of mg / L, the viscosity retention rate is 85% and the plugging rate is 90%, but the corrosion inhibition rate is 0.09 mm / a, and the corrosion inhibition effect is not good in the high temperature acid environment.

[0102] The performance test results show that the deflection agent prepared in this comparative example is not as effective as that in Example 5. This is because the single imidazoline quaternary ammonium salt cannot form a synergistic corrosion inhibition effect with the phytic acid derivative, and cannot form a dense and stable adsorption chelate film on the metal surface. The corrosion inhibition efficiency is significantly reduced at high temperatures, and it cannot meet the corrosion protection requirements of downhole pipes.

[0103] Comparative Example 6 (Baseline: Example 7 | Variable: only isopropanol as the cosolvent) This comparative example provides a method for preparing a diverting agent. The difference from Example 7 is that the cosolvent used is a single isopropanol, which is not compounded with ethylene glycol monobutyl ether. The remaining components, ratios, and preparation processes are exactly the same as in Example 7.

[0104] Performance testing: Mixed with 19% hydrochloric acid at a mass fraction of 9%, at 170℃ and a mineralization of 22×10⁻⁶. 4 Under the given mg / L condition, the system exhibited significant stratification and flocculation, with a viscosity retention rate of only 70%, a blocking rate of 82%, and a rupture solution viscosity of 4.5 mPa. s.

[0105] The performance test results show that the steering agent prepared in this comparative example is not as effective as that in Example 7. This is because isopropanol alone cannot improve the compatibility between fluorinated modified VES and the aqueous phase, resulting in poor solubility and stability of the system, stratification and flocculation, which in turn leads to a comprehensive decrease in high-temperature viscosity retention, steering sealing effect and debinding performance.

[0106] Test case The performance of the products from Examples 1-8 and Comparative Examples 1-6 was tested using the following methods: 1. Viscosity retention: Using a HAAKEMARSIII rheometer, at 170 s... -1 After shearing for 60 min, the viscosity was measured at room temperature and after aging at high temperature for 72 hours, and the viscosity retention rate was calculated.

[0107] 2. Plugging rate: The change in core permeability before and after acid gelation was measured using a high-temperature and high-pressure core flow test device, and the plugging rate was calculated.

[0108] 3. Corrosion inhibition rate: The corrosion rate of the metal specimen was determined by using a high-temperature and high-pressure corrosion tester to simulate the formation temperature and acid conditions.

[0109] 4. Viscosity of the breaking solution: After the acidification reaction is completed, the viscosity of the breaking solution is measured using a rotational viscometer.

[0110] Test results show that, under the corresponding test conditions, the composite diverting agents of Examples 1-8 of the present invention have a viscosity retention rate of ≥85%, a blocking rate of ≥90%, a rupture liquid viscosity of ≤3 mPa·s, and a corrosion inhibition rate of ≤0.05 mm / a. Their overall performance is significantly better than that of Comparative Examples 1-6, which fully demonstrates the technical effect of the synergistic effect of each component.

[0111] The temperature- and salt-resistant VES composite deflector of this invention breaks through the temperature and salt resistance limits of existing deflectors through innovative molecular structure and multi-component synergistic design. It features a simple preparation process, mild reaction conditions, and controllable cost, and is suitable for temperatures of 120-180℃ and mineralization of 0-25×10⁻⁶. 4 Acidizing stimulation of deep, high-temperature, and high-salinity oil and gas reservoirs at a concentration of mg / L. This product can effectively improve acidizing diversion efficiency and oil and gas recovery rate, reduce reservoir damage and development costs, and provide key technical support for the development of deep, high-temperature oil and gas resources, possessing significant economic value and strategic significance.

[0112] The above content is only for illustrating the technical concept of the present invention and should not be construed as limiting the scope of protection of the present invention. Any modifications made to the technical solution based on the technical concept proposed in this invention shall fall within the scope of protection of this invention.

Claims

1. A temperature-resistant and salt-resistant VES composite steering agent, characterized in that, By weight, it includes the following components: 5-15 parts modified VES, 1-3 parts composite corrosion inhibitor, 0.5-2 parts smart responsive degumming agent, 0.1-0.5 parts nano stabilizer, 2-5 parts cosolvent, and the balance is water. The sum of the weight parts of each component is 100 parts. The modified VES is prepared by free radical polymerization of 20-40 parts of fluorinated heterocyclic monomer, 30-50 parts of olefin sulfonate monomer, 1-5 parts of functional crosslinking monomer, 0.3-1 parts of initiator and 50-80 parts of solvent.

2. The temperature-resistant and salt-resistant VES composite steering agent according to claim 1, characterized in that, The fluorinated heterocyclic monomer is selected from at least one of fluoroimidazoline acrylate and trifluoromethylpyridinyl acrylamide; The olefin sulfonate monomer is a compound of sodium 2-acrylamido-2-methylpropanesulfonate and sodium p-styrenesulfonate, wherein the mass ratio of sodium 2-acrylamido-2-methylpropanesulfonate to sodium p-styrenesulfonate is 1:(0.5-2). The functional crosslinking monomer is selected from at least one of N,N'-methylenebisacrylamide and polyethylene glycol diacrylate; The initiator is a redox initiation system of ammonium persulfate and sodium bisulfite, and the mass ratio of ammonium persulfate to sodium bisulfite is 1:(0.3-0.5). The solvent is deionized water.

3. The temperature-resistant and salt-resistant VES composite steering agent according to claim 1, characterized in that, The composite corrosion inhibitor is a compound of oleic acid imidazoline quaternary ammonium salt and inositol hexaphosphate, wherein the mass ratio of oleic acid imidazoline quaternary ammonium salt to inositol hexaphosphate is 2.5:

1.

4. The temperature-resistant and salt-resistant VES composite steering agent according to claim 1, characterized in that, The intelligent responsive decapsulator is a temperature / pH dual-responsive peroxide microcapsule with ammonium persulfate as the core material and polylactic acid-glycolic acid copolymer as the capsule wall material. The molar mass ratio of lactic acid to glycolic acid in the polylactic acid-glycolic acid copolymer is 75:25, and the molecular weight is 40,000.

5. The temperature-resistant and salt-resistant VES composite steering agent according to claim 4, characterized in that, The preparation process of the temperature / pH dual-responsive peroxide microcapsules is as follows: An aqueous phase was prepared by dissolving ammonium persulfate in deionized water. An oil phase was prepared by dissolving polylactic acid-glycolic acid copolymer in dichloromethane; The aqueous phase is added to the oil phase and shear emulsified to form a W / O emulsion. The W / O emulsion was slowly dripped into a polyvinyl alcohol aqueous solution for curing, followed by washing, centrifugation and vacuum drying to obtain ammonium persulfate microcapsule de-gelatinizer, i.e. temperature / pH dual-responsive peroxide microcapsules; The mass ratio of ammonium persulfate to deionized water was 1:5; the mass ratio of polylactic acid-glycolic acid copolymer to dichloromethane was 8:100; the mass ratio of W / O emulsion to polyvinyl alcohol aqueous solution was 1:4; the mass fraction of polyvinyl alcohol aqueous solution was 1%; and the curing time was 2 h.

6. The temperature-resistant and salt-resistant VES composite steering agent according to claim 1, characterized in that, The nano stabilizer is γ-aminopropyltriethoxysilane surface-modified nano silica; The preparation method of the γ-aminopropyltriethoxysilane surface-modified nano-silica is as follows: Nano-silica was dispersed in an ethanol-water mixture, and then γ-aminopropyltriethoxysilane was added. The mixture was stirred and reacted, and then centrifuged, washed with ethanol and vacuum dried in sequence to obtain γ-aminopropyltriethoxysilane-modified nano-silica. The mass ratio of nano-silica to ethanol-water mixture was 1:10; the volume ratio of ethanol to water in the ethanol-water mixture was 9:1; the mass ratio of γ-aminopropyltriethoxysilane to nano-silica was 1.2:10; the stirring reaction was carried out at 60℃ for 3 hours.

7. The temperature-resistant and salt-resistant VES composite steering agent according to claim 1, characterized in that, The cosolvent is a compound of ethylene glycol monobutyl ether and isopropanol, and the mass ratio of the compound of ethylene glycol monobutyl ether and isopropanol is 1:(1-2).

8. A method for preparing a temperature-resistant and salt-resistant VES composite reversing agent as described in any one of claims 1 to 7, characterized in that, Includes the following steps: Fluorine-containing heterocyclic monomers, olefin sulfonate monomers, and functional crosslinking monomers were added to a solvent and stirred to dissolve. After purging with nitrogen to remove oxygen, an initiator was added, and the reaction was carried out at a constant temperature at a first set temperature. After the reaction was completed, precipitation, washing, and drying were carried out in sequence to obtain modified VES. Water and co-solvent are mixed evenly, and modified VES, composite corrosion inhibitor and nano stabilizer are added in sequence at a second set temperature. The mixture is stirred and dissolved, and then smart responsive degumming agent is added. The mixture is stirred at room temperature to obtain temperature-resistant and salt-resistant VES composite deflector.

9. The method for preparing a temperature-resistant and salt-resistant VES composite steering agent according to claim 8, characterized in that, The first set temperature is 60-80℃, and the constant temperature reaction time is 4-6 hours; the second set temperature is 40-50℃.

10. The application of the temperature-resistant and salt-resistant VES composite diverting agent as described in any one of claims 1 to 7 in acidizing operations of deep, high-temperature, and high-salinity oil and gas reservoirs, characterized in that... The temperature-resistant and salt-resistant VES composite reversing agent is compounded with an acid solution to form a reversing acid. The mass fraction of the temperature-resistant and salt-resistant VES composite reversing agent in the reversing acid is 3-10%. The acid solution is hydrochloric acid, fluoroboric acid, or tereic acid. The tereic acid is obtained by mixing hydrochloric acid and hydrofluoric acid at a volume ratio of 12:

3. The diverting acid is suitable for temperatures of 120-180℃ and mineralization of 0-25×10⁻⁶. 4 Acidizing stimulation operations for deep, high-temperature, and high-salinity oil and gas reservoirs with a concentration of mg / L.