Multifunctional plugging remover for oil extraction and acidification and preparation method thereof

Abstract

The application discloses a multifunctional plugging removing agent for oil extraction and acidification of oil fields and a preparation method thereof. The plugging removing agent comprises the following raw materials in percentage: 10-15% of hydrochloric acid, 5-8% of formic acid, 5-8% of citric acid, 0.3-0.5% of OP-10 and 1-1.5% of a modified additive, and the balance is water. In the using process of the acidification plugging removing agent, the modified additive can reduce the interfacial tension, change the rock surface into water wettability, make the residual acid after reaction and loose particles more easily carried back, significantly improve the permeability recovery rate, the nano silicon dioxide in the modified additive can fill the cavity of the surface polysiloxane chain segment, can prevent the curling of the polysiloxane chain segment and the collapse of the network structure, and further improve the salt resistance of the modified additive, ensure the penetration effect of the acid liquid, the cage type silsesquioxane structure on the surface can form a dense three-dimensional network, greatly improve the mechanical strength, shear resistance and long-term thermal stability of the oil displacement system, and is not easy to degrade and fail.

Description

Technical Field

[0001] This invention relates to the field of unblocking agent preparation technology, specifically to a multifunctional unblocking agent for oilfield production and acidizing, and its preparation method. Background Technology

[0002] In the exploration, development, and production processes of oilfields, formation blockage is one of the core problems leading to decreased oil well productivity and increased injection pressure in water injection wells. As oilfield development enters its mid-to-late stages, the extraction targets become increasingly complex, and formation blockage has evolved from early simple inorganic scale blockage to complex blockage involving inorganic scale, organic matter (such as asphaltene, colloids, and paraffin), bacterial metabolites, polymer residues, and mechanical impurities. This complex blockage severely restricts the effective utilization of oil and gas resources, and traditional single-function unblocking agents are no longer sufficient to meet the demands for efficient and long-lasting unblocking. Therefore, developing a multifunctional unblocking agent that integrates multiple functions and can synergistically address complex blockages has become a key technology urgently needing to be mastered in the field of oilfield chemistry. Summary of the Invention

[0003] The purpose of this invention is to provide a multifunctional unblocking agent for oilfield production and acidizing, and its preparation method, to solve the problems of poor oil displacement effect of current unblocking agents and significant decrease in effectiveness under high-speed shear and high-temperature environments.

[0004] The objective of this invention can be achieved through the following technical solutions: A method for preparing a multifunctional unblocking agent for oilfield production and acidizing specifically includes the following steps: Step A1: Mix 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-in-3,7,14-triol and tetrahydrofuran, purge with nitrogen, stir and add trichlorosilane and triethylamine at a speed of 150-200 r / min and a temperature of 20-25℃, and react for 15-17 h to obtain a monofunctional cage-type silsesquioxane; Step A2: Mix monofunctional cage-type silsesquioxane, acrylic acid, chloroplatinic acid and toluene, purge with nitrogen, and react for 6-8 hours at a speed of 150-200 r / min and a temperature of 85-90℃ to obtain carboxylated cage-type silsesquioxane. Mix carboxylated cage-type silsesquioxane, modified silica, p-toluenesulfonic acid and xylene, purge with nitrogen, and react for 8-10 hours at a speed of 120-150 r / min and a temperature of 110-115℃ to obtain modified additive. Step A3: Weigh the following raw materials in the following percentages: 10-15% hydrochloric acid, 5-8% formic acid, 5-8% citric acid, 0.3-0.5% OP-10 and 1-1.5% modified additives, with the balance being water. Mix the raw materials evenly to obtain a multifunctional unblocking agent for oilfield production and acidizing.

[0005] Further, the ratio of 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triol, trichlorosilane and triethylamine in step A1 is 5g:0.8g:3mL.

[0006] Furthermore, in step A2, the molar ratio of the monofunctional cage-like silsesquioxane to acrylic acid is 1:1, the amount of chloroplatinic acid is 0.01% of the mass of acrylic acid, the molar ratio of the carboxylated cage-like silsesquioxane to the hydroxyl groups on the modified silica is 1.1:1, and the amount of p-toluenesulfonic acid is 0.1% of the mass of the modified silica.

[0007] Furthermore, the modified silica is prepared by the following steps: Step B1: Disperse nano-silica in ethanol, stir and add 3-mercaptopropyltrimethoxysilane and deionized water at a speed of 200-300 r / min and a temperature of 60-70℃, and react for 3-5 h to obtain mercaptosilica. Mix lithium dimethylsilyl alcohol and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at a speed of 150-200 r / min and a temperature of 0℃, raise the temperature to 20-25℃ and react for 8-10 h, then add allyltrichlorosilane and continue the reaction for 1-1.5 h to obtain branched polysiloxane. Step B2: Branched polysiloxane, mercaptoized silica, benzophenone and DMF are mixed and reacted for 1-1.5 h under conditions of 300-500 r / min, 20-25℃ and 365nm ultraviolet irradiation to obtain pretreated silica. Pretreated silica, allyl glycidyl ether, caster catalyst and toluene are mixed, and nitrogen gas is introduced for protection. The mixture is reacted for 10-12 h under conditions of 150-200 r / min and 80-85℃ to obtain epoxy silica. Step B3: Mix epoxy silica, n-hexylamine and DMF evenly. Stir and add sodium hydroxide solution at a speed of 200-300 r / min and a temperature of 60-65℃, maintaining the pH value at 9. After reacting for 6-8 hours, add sodium ethylene oxide methanesulfonate and continue reacting for 8-10 hours. Filter to remove the filtrate, dry the substrate, and obtain modified silica.

[0008] Furthermore, the amount of 3-mercaptopropyltrimethoxysilane used in step B1 is 3% of the mass of nano-silica, and the molar ratio of Si-Cl bonds on lithium dimethylsilyl alcohol, tetramethylcyclotetrasiloxane and allyltrichlorosilane is 1:4:1.

[0009] Furthermore, in step B2, the molar ratio of branched polysiloxane to mercapto groups on mercaptodioxane is 1:1, the amount of benzophenone used is 0.1% of the mass of branched polysiloxane, the molar ratio of Si-H bonds on pretreated silica to allyl alcohol glycidyl ether is 1:1, and the amount of caster catalyst used is 0.01% of the mass of allyl alcohol glycidyl ether.

[0010] Furthermore, in step B3, the molar ratio of the epoxy groups on the epoxy silica, n-hexylamine, and sodium ethylene oxide methane sulfonate is 1:1:1.1, and the mass fraction of the sodium hydroxide solution is 30%.

[0011] The beneficial effects of this invention: This invention discloses a multifunctional unblocking agent for oilfield production and acidizing, comprising the following raw materials: hydrochloric acid, formic acid, citric acid, OP-10, a modifying additive, and water. The modifying additive reacts with 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triol and trichlorosilane to achieve the desired effect. Monofunctional cage-like silsesquioxanes are prepared by reacting the hydroxyl groups on alkyl-3,7,14-triol with the Si-Cl groups on trichlorosilane. The monofunctional cage-like silsesquioxanes are then reacted with acrylic acid, causing the Si-H bonds on the monofunctional cage-like silsesquioxanes to react with the double bonds on the acrylic acid, resulting in carboxylated cage-like silsesquioxanes. Finally, the carboxylated cage-like silsesquioxanes are reacted with modified silica, causing the carboxyl groups on the carboxylated cage-like silsesquioxanes to react with the hydroxyl groups on the modified silica, resulting in a modified additive.

[0012] Modified silica was prepared by treating nano-silica with 3-mercaptopropyltrimethoxysilane to graft mercapto groups onto the surface, thus obtaining mercapto silica. Dimethylsilyllithium was used as an initiator and tetramethylcyclotetrasiloxane as a polymerization monomer to prepare a polysiloxane with lithium silanolate at one end and Si-H bonds at the other. Allyltrichlorosilane was then added, causing the Si-Cl bonds on the allyltrichlorosilane to react with the lithium silanolate, yielding a branched polysiloxane. The branched polysiloxane and mercapto silica were then reacted under ultraviolet light. The double bonds on branched polysiloxane react with the thiol groups on mercaptosilica to prepare pretreated silica. The pretreated silica is then reacted with allyl glycidyl ether to react with the double bonds on allyl glycidyl ether to prepare epoxy silica. The epoxy silica is then reacted with n-hexylamine to react with the epoxy groups on n-hexylamine. Finally, sodium ethylene oxide methanesulfonate and a secondary amine are added to react and prepare modified silica.

[0013] During use, this acid dissolving agent reduces interfacial tension, allowing acid to penetrate finer pores. It also alters the rock surface to be water-wet, making it easier for residual acid and loose particles to be carried back, significantly improving permeability recovery. The nano-silica in the additive fills the cavities of the polysiloxane segments on the surface, preventing the curling of the polysiloxane segments and the collapse of the network structure, thus enhancing the additive's salt resistance and ensuring effective acid penetration. The cage-like silsesquioxane structure on the surface forms a dense three-dimensional network, significantly improving the mechanical strength, shear resistance, and long-term thermal stability of the oil displacement system, making it less prone to degradation and failure. Detailed Implementation

[0014] The technical solutions in the embodiments of the present invention will be clearly and completely described below. 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 skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1: A method for preparing a multifunctional unblocking agent for oilfield production and acidizing, specifically including the following steps: Step A1: 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-in-3,7,14-triol and tetrahydrofuran were mixed and protected with nitrogen. Under the conditions of 150 r / min and 20 °C, trichlorosilane and triethylamine were added and the mixture was stirred for 15 h to obtain a monofunctional cage-type silsesquioxane. Step A2: Mix monofunctional cage-type silsesquioxane, acrylic acid, chloroplatinic acid and toluene, purge with nitrogen, and react for 6 hours at 150 r / min and 85°C to obtain carboxylated cage-type silsesquioxane. Mix carboxylated cage-type silsesquioxane, modified silica, p-toluenesulfonic acid and xylene, purge with nitrogen, and react for 8 hours at 120 r / min and 110°C to obtain modified additive. Step A3: Weigh the following raw materials in the following percentages: 10% hydrochloric acid, 5% formic acid, 5% citric acid, 0.3% OP-10 and 1% modified additives, with the remainder being water. Mix the raw materials evenly to obtain a multifunctional unblocking agent for oilfield production and acidizing.

[0016] The ratio of 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triol, trichlorosilane and triethylamine used in step A1 is 5g:0.8g:3mL.

[0017] In step A2, the molar ratio of the monofunctional cage-type silsesquioxane to acrylic acid is 1:1, the amount of chloroplatinic acid is 0.01% of the mass of acrylic acid, the molar ratio of the carboxylated cage-type silsesquioxane to the hydroxyl groups on the modified silica is 1.1:1, and the amount of p-toluenesulfonic acid is 0.1% of the mass of the modified silica.

[0018] The modified silica is prepared by the following steps: Step B1: Disperse nano-silica in ethanol, stir and add 3-mercaptopropyltrimethoxysilane and deionized water at 200 r / min and 60 °C, and react for 3 h to obtain mercaptosilica. Mix lithium dimethylsilyl alcohol and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at 150 r / min and 0 °C, raise the temperature to 20 °C and react for 8 h. Then add allyltrichlorosilane and continue the reaction for 1 h to obtain branched polysiloxane. Step B2: Branched polysiloxane, mercaptoized silica, benzophenone and DMF are mixed and reacted for 1 hour under the conditions of 300 r / min, 20℃ and 365 nm ultraviolet irradiation to obtain pretreated silica. Pretreated silica, allyl glycidyl ether, caster catalyst and toluene are mixed, nitrogen gas is introduced for protection, and the reaction is carried out for 10 hours under the conditions of 150 r / min and 80℃ to obtain epoxy silica. Step B3: Mix epoxy silica, n-hexylamine and DMF evenly, stir and add sodium hydroxide solution at 200 r / min and 60℃, maintain pH value of 9, and react for 6 h. Then add sodium ethylene oxide methane sulfonate and continue the reaction for 8 h. Filter to remove filtrate, dry the substrate, and obtain modified silica.

[0019] The amount of 3-mercaptopropyltrimethoxysilane used in step B1 is 3% of the mass of nano-silica, and the molar ratio of Si-Cl bonds on lithium dimethylsilyl alcohol, tetramethylcyclotetrasiloxane and allyltrichlorosilane is 1:4:1.

[0020] In step B2, the molar ratio of branched polysiloxane to mercapto groups on mercaptodisilane is 1:1, the amount of benzophenone used is 0.1% of the mass of branched polysiloxane, the molar ratio of Si-H bonds on pretreated silica to allyl alcohol glycidyl ether is 1:1, and the amount of caster catalyst used is 0.01% of the mass of allyl alcohol glycidyl ether.

[0021] In step B3, the molar ratio of epoxy groups on the epoxy silica, n-hexylamine, and sodium ethylene oxide methane sulfonate is 1:1:1.1, and the mass fraction of the sodium hydroxide solution is 30%.

[0022] Example 2: A method for preparing a multifunctional unblocking agent for oilfield production and acidizing, specifically including the following steps: Step A1: 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-in-3,7,14-triol and tetrahydrofuran were mixed and protected with nitrogen. Under the conditions of 150 r / min and 25 °C, trichlorosilane and triethylamine were added and the mixture was stirred for 16 h to obtain a monofunctional cage-type silsesquioxane. Step A2: Mix monofunctional cage-type silsesquioxane, acrylic acid, chloroplatinic acid and toluene, purge with nitrogen, and react for 7 h at a speed of 150 r / min and a temperature of 90 °C to obtain carboxylated cage-type silsesquioxane. Mix carboxylated cage-type silsesquioxane, modified silica, p-toluenesulfonic acid and xylene, purge with nitrogen, and react for 9 h at a speed of 120 r / min and a temperature of 115 °C to obtain modified additive. Step A3: Weigh the following raw materials in the following percentages: 13% hydrochloric acid, 6.5% formic acid, 6.5% citric acid, 0.4% OP-10 and 1.3% modified additives, with the remainder being water. Mix the raw materials evenly to obtain a multifunctional unblocking agent for oilfield production and acidizing.

[0023] The ratio of 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triol, trichlorosilane and triethylamine used in step A1 is 5g:0.8g:3mL.

[0024] In step A2, the molar ratio of the monofunctional cage-type silsesquioxane to acrylic acid is 1:1, the amount of chloroplatinic acid is 0.01% of the mass of acrylic acid, the molar ratio of the carboxylated cage-type silsesquioxane to the hydroxyl groups on the modified silica is 1.1:1, and the amount of p-toluenesulfonic acid is 0.1% of the mass of the modified silica.

[0025] The modified silica is prepared by the following steps: Step B1: Disperse nano-silica in ethanol, stir and add 3-mercaptopropyltrimethoxysilane and deionized water at 200 r / min and 65 °C, and react for 4 h to obtain mercaptosilica. Mix lithium dimethylsilyl alcohol and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at 150 r / min and 0 °C, raise the temperature to 25 °C and react for 9 h. Then add allyltrichlorosilane and continue the reaction for 1.5 h to obtain branched polysiloxane. Step B2: Branched polysiloxane, mercaptoized silica, benzophenone and DMF are mixed and reacted for 1.5 h under conditions of 300 r / min, 25 °C and 365 nm ultraviolet irradiation to obtain pretreated silica. Pretreated silica, allyl glycidyl ether, caster catalyst and toluene are mixed, nitrogen gas is introduced for protection, and the reaction is carried out for 11 h under conditions of 150 r / min and 85 °C to obtain epoxy silica. Step B3: Mix epoxy silica, n-hexylamine and DMF evenly, stir and add sodium hydroxide solution at 200 r / min and 65℃, maintain pH value of 9, and react for 7 h. Then add sodium ethylene oxide methanesulfonate and continue to react for 9 h. Filter to remove filtrate, dry the substrate, and obtain modified silica.

[0026] The amount of 3-mercaptopropyltrimethoxysilane used in step B1 is 3% of the mass of nano-silica, and the molar ratio of Si-Cl bonds on lithium dimethylsilyl alcohol, tetramethylcyclotetrasiloxane and allyltrichlorosilane is 1:4:1.

[0027] In step B2, the molar ratio of branched polysiloxane to mercapto groups on mercaptodisilane is 1:1, the amount of benzophenone used is 0.1% of the mass of branched polysiloxane, the molar ratio of Si-H bonds on pretreated silica to allyl alcohol glycidyl ether is 1:1, and the amount of caster catalyst used is 0.01% of the mass of allyl alcohol glycidyl ether.

[0028] In step B3, the molar ratio of epoxy groups on the epoxy silica, n-hexylamine, and sodium ethylene oxide methane sulfonate is 1:1:1.1, and the mass fraction of the sodium hydroxide solution is 30%.

[0029] Example 3: A method for preparing a multifunctional unblocking agent for oilfield production and acidizing, specifically including the following steps: Step A1: 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-in-3,7,14-triol and tetrahydrofuran were mixed and protected with nitrogen. Under the conditions of 200 r / min and 25 °C, trichlorosilane and triethylamine were added and the mixture was stirred for 17 h to obtain a monofunctional cage-type silsesquioxane. Step A2: Mix monofunctional cage-type silsesquioxane, acrylic acid, chloroplatinic acid and toluene, purge with nitrogen, and react for 8 hours at 200 r / min and 90 °C to obtain carboxylated cage-type silsesquioxane. Mix carboxylated cage-type silsesquioxane, modified silica, p-toluenesulfonic acid and xylene, purge with nitrogen, and react for 10 hours at 150 r / min and 115 °C to obtain modified additive. Step A3: Weigh the following raw materials in the following percentages: 15% hydrochloric acid, 8% formic acid, 8% citric acid, 0.5% OP-10 and 1.5% modified additives, with the remainder being water. Mix the raw materials evenly to obtain a multifunctional unblocking agent for oilfield production and acidizing.

[0030] The ratio of 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triol, trichlorosilane and triethylamine used in step A1 is 5g:0.8g:3mL.

[0031] In step A2, the molar ratio of the monofunctional cage-type silsesquioxane to acrylic acid is 1:1, the amount of chloroplatinic acid is 0.01% of the mass of acrylic acid, the molar ratio of the carboxylated cage-type silsesquioxane to the hydroxyl groups on the modified silica is 1.1:1, and the amount of p-toluenesulfonic acid is 0.1% of the mass of the modified silica.

[0032] The modified silica is prepared by the following steps: Step B1: Disperse nano-silica in ethanol, stir and add 3-mercaptopropyltrimethoxysilane and deionized water at 300 r / min and 70 °C, and react for 5 h to obtain mercaptosilica. Mix lithium dimethylsilyl alcohol and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane at 200 r / min and 0 °C, raise the temperature to 25 °C and react for 10 h. Then add allyltrichlorosilane and continue the reaction for 1.5 h to obtain branched polysiloxane. Step B2: Branched polysiloxane, mercaptoized silica, benzophenone and DMF are mixed and reacted for 1.5 h under conditions of 500 r / min, 25 °C and 365 nm ultraviolet irradiation to obtain pretreated silica. Pretreated silica, allyl glycidyl ether, caster catalyst and toluene are mixed, nitrogen gas is introduced for protection, and the reaction is carried out for 12 h under conditions of 200 r / min and 85 °C to obtain epoxy silica. Step B3: Mix epoxy silica, n-hexylamine and DMF evenly, stir and add sodium hydroxide solution at 300 r / min and 65℃, maintain pH value of 9, and react for 8 h. Then add sodium ethylene oxide methanesulfonate and continue the reaction for 10 h. Filter to remove filtrate, dry the substrate, and obtain modified silica.

[0033] The amount of 3-mercaptopropyltrimethoxysilane used in step B1 is 3% of the mass of nano-silica, and the molar ratio of Si-Cl bonds on lithium dimethylsilyl alcohol, tetramethylcyclotetrasiloxane and allyltrichlorosilane is 1:4:1.

[0034] In step B2, the molar ratio of branched polysiloxane to mercapto groups on mercaptodisilane is 1:1, the amount of benzophenone used is 0.1% of the mass of branched polysiloxane, the molar ratio of Si-H bonds on pretreated silica to allyl alcohol glycidyl ether is 1:1, and the amount of caster catalyst used is 0.01% of the mass of allyl alcohol glycidyl ether.

[0035] In step B3, the molar ratio of epoxy groups on the epoxy silica, n-hexylamine, and sodium ethylene oxide methane sulfonate is 1:1:1.1, and the mass fraction of the sodium hydroxide solution is 30%.

[0036] Comparative Example 1: This comparative example uses lauric acid instead of carboxylated cage-like silsesquioxane, while the other steps are the same as in Example 1.

[0037] Comparative Example 2: This comparative example did not include nano-silica compared to Example 1, but the remaining steps were the same.

[0038] Comparative Example 3: This comparative example uses butane instead of sodium ethylene oxide methanesulfonate, but the other steps are the same as in Example 1.

[0039] Crude oil was mixed with the unblocking agent solutions prepared in Examples 1-3 and Comparative Examples 1-3 to obtain a mixture in which the unblocking agent solution accounted for 0.5 wt% of the crude oil. The mixture was then subjected to heat treatment at temperatures of 50°C, 65°C, and 80°C for 20 min, and the final temperature was determined in 1.24 s. -1 The interfacial tension was measured at the shear rate, and then kept at 50℃ for 20 min, followed by a further measurement at 60℃. -1 The interfacial tension was measured at a certain shear rate, and the results are shown in Table 1 below.

[0040] Table 1

[0041] As shown in Table 1, this application has excellent shear resistance and temperature resistance.

[0042] The above description is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention or exceed the scope defined in the claims, they should all fall within the protection scope of the present invention.

Claims

1. A method for preparing a multifunctional unblocking agent for oilfield production and acidizing, characterized in that: Specifically, the steps include the following: Step A1: Mix 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triol and tetrahydrofuran, purge with nitrogen, stir and add trichlorosilane and triethylamine to react and obtain a monofunctional cage-type silsesquioxane; Step A2: Mix monofunctional cage-type silsesquioxane, acrylic acid, chloroplatinic acid and toluene, and react under nitrogen protection to obtain carboxylated cage-type silsesquioxane. Mix carboxylated cage-type silsesquioxane, modified silica, p-toluenesulfonic acid and xylene, and react under nitrogen protection to obtain modified additive. Step A3: Weigh the following raw materials in the following percentages: 10-15% hydrochloric acid, 5-8% formic acid, 5-8% citric acid, 0.3-0.5% OP-10 and 1-1.5% modified additives, with the balance being water. Mix the raw materials evenly to obtain a multifunctional unblocking agent for oilfield production and acidizing.

2. The preparation method of a multifunctional unblocking agent for oilfield production and acidizing according to claim 1, characterized in that: The ratio of 1,3,5,7,9,11,14-heptaisobutyltricyclo[7.3.3.15,11]heptasiloxane-3,7,14-triol, trichlorosilane and triethylamine used in step A1 is 5g:0.8g:3mL.

3. The preparation method of a multifunctional unblocking agent for oilfield production and acidizing according to claim 1, characterized in that: The molar ratio of the monofunctional cage-type silsesquioxane and acrylic acid in step A2 is 1:1, and the molar ratio of the carboxylated cage-type silsesquioxane and the hydroxyl groups on the modified silica is 1.1:

1.

4. The preparation method of a multifunctional unblocking agent for oilfield production and acidizing according to claim 1, characterized in that: The modified silica is prepared by the following steps: Step B1: Disperse nano-silica in ethanol, stir and add 3-mercaptopropyltrimethoxysilane and deionized water to react and obtain mercaptosilica. Mix lithium dimethylsilyl alcohol and tetrahydrofuran, purge with nitrogen, stir and add tetramethylcyclotetrasiloxane, heat and react, then add allyltrichlorosilane and continue the reaction to obtain branched polysiloxane. Step B2: Branched polysiloxane, mercaptoized silica, benzophenone and DMF are mixed and reacted under ultraviolet light to obtain pretreated silica. Pretreated silica, allyl alcohol glycidyl ether, castor catalyst and toluene are mixed and reacted under nitrogen protection to obtain epoxy silica. Step B3: Mix epoxy silica, n-hexylamine and DMF evenly, stir and add sodium hydroxide solution, react and then add sodium ethylene oxide methanesulfonate, continue the reaction, filter to remove the filtrate, dry the substrate to obtain modified silica.

5. The preparation method of a multifunctional unblocking agent for oilfield production and acidizing according to claim 4, characterized in that: The amount of 3-mercaptopropyltrimethoxysilane used in step B1 is 3% of the mass of nano-silica, and the molar ratio of Si-Cl bonds on lithium dimethylsilyl alcohol, tetramethylcyclotetrasiloxane and allyltrichlorosilane is 1:4:

1.

6. The preparation method of a multifunctional unblocking agent for oilfield production and acidizing according to claim 4, characterized in that: In step B2, the molar ratio of branched polysiloxane to mercapto groups on mercaptodioxane is 1:1, and the molar ratio of Si-H bonds on pretreated silica to allyl glycidyl ether is 1:

1.

7. The preparation method of a multifunctional unblocking agent for oilfield production and acidizing according to claim 4, characterized in that: The molar ratio of epoxy groups, n-hexylamine, and sodium ethylene oxide methane sulfonate on the epoxy silica in step B3 is 1:1:1.

1.

8. A multifunctional unblocking agent for oilfield production and acidizing, characterized in that: It is prepared according to the preparation method described in claims 1-7.

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