Ultrahigh-temperature-resistant acid liquid system as well as preparation method and application thereof

Abstract

The invention discloses an ultra-high-temperature-resistant acid liquid system, a preparation method and application thereof, and belongs to the field of oilfield chemistry. The ultrahigh-temperature-resistant acid liquid system comprises the following raw materials in percentage by weight: 0.4%-0.6% of a thickening agent, 0.05%-0.1% of a complexing agent, 4%-6% of a corrosion inhibitor, 0.1%-0.3% of a surfactant, 0.1%-0.3% of a stabilizer and the balance of hydrochloric acid. The ultra-high-temperature-resistant acid liquid system is stable in performance under the ultra-high-temperature condition, the retarding effect can be efficiently achieved, the acid liquid can enter a farther stratum under the ultra-high-temperature condition, and the transformation volume is increased; the corrosion inhibitor in the ultra-high-temperature-resistant acid liquid system has strong action capacity with metal, so that the metal pipe column can be efficiently protected, and the construction safety under the ultra-high-temperature condition is ensured; and the surfactant with low surface tension in the ultrahigh-temperature-resistant acid liquid system enables the residual acid liquid after construction to quickly return and discharge out of the stratum, so that the reservoir damage caused by retention of the residual acid in the stratum is reduced.

Description

Technical Field

[0001] The present invention relates to the field of oilfield chemistry, and in particular to an ultrahigh temperature resistant acid solution system, a preparation method and applications thereof. Background Art

[0002] A significant portion of the reservoirs currently being developed in my country are ultra-high-temperature reservoirs. Conventional acidizing techniques for transforming these reservoirs can cause the acid to react violently near the wellbore, leading to severe corrosion of underground tubing. This not only results in significant acid consumption near the wellbore, but also poses significant safety risks to underground operations, significantly impacting the effectiveness of the acidizing operation. For these reservoirs, an acid system with both high-temperature resistance and high-temperature corrosion inhibition is required to achieve the desired acidizing effect.

[0003] Currently, retarded acid systems are commonly used in oilfield acidizing to slow the acid-rock reaction rate. However, existing retarded acid systems are no longer sufficient for acidizing ultra-high temperature reservoirs. This is because the temperature of ultra-high temperature reservoirs often exceeds 180°C. Conventional acid systems react very rapidly at ultra-high temperatures. Conventional retarded acids can slow down the acid-rock reaction rate by affecting different stages of the reaction. However, because the temperature of ultra-high temperature reservoirs has far exceeded the tolerance limit of today's retarded acid systems, the viscosity of the retarded acid decreases, and it cannot form a complex network structure to prevent contact between the acid and the rock, or it cannot be adsorbed on the rock surface to form an effective barrier layer, resulting in the corrosion inhibitor being unable to form a corrosion inhibition layer on the surface of the underground pipe. Therefore, an acid system that can maintain a certain degree of retarding and corrosion inhibition capacity at ultra-high temperatures has become a very effective means of transforming ultra-high temperature reservoirs.

[0004] In the existing literature, Yang Ming et al. designed and prepared a series of polyacrylamide-based cationic heat-resistant and acid-resistant thickeners in the "Preparation and Performance Evaluation of 180°C Thickened Acid System" and studied their basic properties. At the same time, they screened out corrosion inhibitors suitable for high-temperature acid solutions and combined them with other additives to form high-temperature resistant thickened acid, and further studied the performance of the thickened acid. After a 180°C high-temperature and high-pressure dynamic corrosion test, the corrosion rate of N80 steel sheet was only 41.614g / (m 2 h). At 180°C, 170s -1 The viscosity of the lower thickening acid system is maintained at 33.258 mPa·s (Science, Technology and Engineering, Issue 23, 2024, Pages 9827-9833), but the overall temperature resistance of the acid still cannot meet the requirements for ultra-high temperature reservoirs with higher temperatures.

[0005] High-temperature resistance is a key area of ​​research in acid systems. The high-temperature-resistant groups on the molecular chains of thickeners in existing acid systems have weak high-temperature resistance. Under shear, their viscosity-increasing ability is almost lost, resulting in a serious lack of acid systems that are currently resistant to ultra-high temperatures. Corrosion inhibitors can slow the corrosion of acid on metal materials such as underground casing and oil pipes, but current retarders cannot guarantee the corrosion resistance of underground pipes at ultra-high temperatures. Existing acid systems have poor ultra-high temperature resistance, requiring extensive preliminary work during construction to reduce the impact of ultra-high temperatures on the formation, increasing the complexity of on-site construction. Existing acid systems are not suitable for ultra-high-temperature reservoirs. Summary of the Invention

[0006] The purpose of the present invention is to provide an ultrahigh temperature resistant acid liquid system, a preparation method and an application thereof, so as to solve the technical problem that the acid liquid system in the prior art has poor high temperature resistance.

[0007] To achieve the above object, an embodiment of the present invention provides an ultra-high temperature acid solution resistant system, comprising the following raw materials in proportion by weight: 0.4%-0.6% thickener, 0.05%-0.1% complexing agent, 4%-6% corrosion inhibitor, 0.1%-0.3% surfactant, 0.1%-0.3% stabilizer, and the balance being hydrochloric acid; The thickener is a copolymer of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide.

[0008] The corrosion inhibitor includes the following raw materials in proportion by weight: 15%-30% of 1,4-bis((butyryloxy)-3-methylimidazoline)butene, 20%-30% of small molecule alcohol, 2%-6% of propargyl alcohol, 5%-10% of formic acid, 0.5%-2% of alkyl polyoxyethylene ether, and the balance is water.

[0009] In one preferred embodiment of the present invention, the mass percentages of acrylamide: 2-acrylamido-2-methylpropanesulfonic acid: acrylic acid: dimethyldodecyl (2-acrylamidoethyl) ammonium bromide are 3-4: 0.5: 0.5: 3.

[0010] In one preferred embodiment of the present invention, the complexing agent is an aqueous solution of chromium trichloride, the surfactant is an aqueous solution of perfluoroalkyl polyoxyethylene ether, and the stabilizer is a mixture of sodium isoxadiazine and citric acid.

[0011] In one preferred embodiment of the present invention, the small molecule alcohol is a mixture of methanol and ethylene glycol, and the mass ratio of methanol to ethylene glycol is 2-5:1.

[0012] In one preferred embodiment of the present invention, the alkyl group of the alkyl polyoxyethylene ether is any one of octyl group and octyl group.

[0013] The present invention also discloses a method for preparing an ultrahigh temperature resistant acid solution system, comprising: adding a thickener, a corrosion inhibitor, a stabilizer, and a surfactant to hydrochloric acid respectively, mixing and stirring uniformly, and adding a complexing agent when injecting the mixture into the formation to obtain the ultrahigh temperature resistant acid solution system; The preparation method of the thickener comprises: adding 2-acrylamide-2-methylpropanesulfonic acid to water, adjusting the pH, and then sequentially adding acrylamide, acrylic acid, and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, mixing, and reacting to obtain the thickener; The preparation method of the corrosion inhibitor comprises: sequentially adding a small molecule alcohol, propargyl alcohol, formic acid, 1,4-bis((butyryloxy)-3-methylimidazoline)butene and an alkyl polyoxyethylene ether and stirring to obtain the corrosion inhibitor.

[0014] One preferred embodiment of the present invention provides a method for preparing a thickener, comprising: adding 2-acrylamide-2-methylpropanesulfonic acid to water; adjusting the pH; sequentially adding acrylamide, acrylic acid, and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, and mixing and stirring; and after stirring, adding sodium sulfite and sodium thiosulfate to react to obtain a thickener.

[0015] In one preferred embodiment of the present invention, the mass percentages of acrylamide: 2-acrylamido-2-methylpropanesulfonic acid: acrylic acid: dimethyldodecyl (2-acrylamidoethyl) ammonium bromide are 3-4: 0.5: 0.5: 3.

[0016] One preferred embodiment of the present invention is a method for preparing 1,4-bis((butyryloxy)-3-methylimidazolinium)butene, comprising: reacting N-hydroxymethylimidazoline and acyl chloride in tetrahydrofuran, rotary evaporation to obtain a product, washing the product, adding n-hexane and 1,4-dibromobutene, stirring and reacting, and filtering to obtain 1,4-bis((butyryloxy)-3-methylimidazolinium)butene.

[0017] In one preferred embodiment of the present invention, the acyl chloride is any one of butyryl chloride and hexanoyl chloride.

[0018] In one preferred embodiment of the present invention, the alkyl group of the alkyl polyoxyethylene ether is either octyl or octyl, the small molecule alcohol is a mixture of methanol and ethylene glycol, and the mass ratio of methanol to ethylene glycol is 2-5:1.

[0019] In one preferred embodiment of the present invention, the complexing agent is an aqueous solution of chromium trichloride, the surfactant is an aqueous solution of perfluoroalkyl polyoxyethylene ether, and the stabilizer is a mixture of sodium isoxadiazine and citric acid.

[0020] The invention also discloses an application of an ultra-high temperature resistant acid solution system, which is used for acidizing and reforming ultra-high temperature reservoirs.

[0021] In summary, the beneficial effects of the present invention are: 1. The ultrahigh temperature resistant acid liquid system of the present invention has stable performance under ultrahigh temperature conditions and can effectively exert a retarding effect, enabling the acid liquid to penetrate farther into the formation under ultrahigh temperature conditions and increase the transformation volume. In addition, the corrosion inhibitor in the ultrahigh temperature resistant acid liquid system has a strong ability to interact with metals and can effectively protect the metal pipe column, ensuring the safety of construction under ultrahigh temperature conditions. The low surface tension surfactant in the ultrahigh temperature resistant acid liquid system enables the residual acid liquid after construction to be quickly discharged back into the formation, reducing the reservoir damage caused by the retention of residual acid in the formation.

[0022] 2. The thickener of the ultra-high temperature resistant acid liquid system of the present invention has high viscosity after cross-linking, which can effectively slow down the transmission speed of the acid liquid and reduce the reaction speed between the acid liquid and the rock; and the cross-linked acid liquid system has a high cross-linking density and strong shear resistance, which can effectively cover the metal surface and avoid contact between the acid liquid and the metal.

[0023] 3. The ultrahigh temperature corrosion inhibitor contained in the ultrahigh temperature acid solution resistant system of the present invention contacts the metal through the double bonds and ring structures contained therein through coordination bonds to form a complex structure, thereby isolating the acid solution from the metal and preventing the metal from being corroded by the acid solution at high temperatures.

[0024] 4. The surfactant in the ultra-high temperature resistant acid solution system of the present invention can be effectively adsorbed on the rock surface under ultra-high temperature conditions, reducing the surface tension between water and rock and promoting the return and discharge of the reacted acid solution from the formation.

[0025] 5. The ultra-high temperature acid solution system of the present invention can meet the requirements of smooth construction under ultra-high temperature conditions and ensure the construction effect.

[0026] Other features and advantages of the present invention will be described in the following description, and part of them will become obvious from the description, or will be understood by practicing the present invention. The purpose and other advantages of the present invention can be described by the effects described in the description. DETAILED DESCRIPTION

[0027] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the contents of the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts shall fall within the scope of protection of the present invention.

[0028] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to form one or more new numerical ranges, and these numerical ranges should be considered to be specifically disclosed in the present invention.

[0029] The invention discloses an ultrahigh temperature acid solution resistant system, which comprises the following raw materials in proportion by weight: 0.4%-0.6% of a thickener, 0.05%-0.1% of a complexing agent, 4%-6% of a corrosion inhibitor, 0.1%-0.3% of a surfactant, 0.1%-0.3% of a stabilizer, and the balance being hydrochloric acid.

[0030] The thickener is a copolymer of acrylamide, 2-acrylamide-2-methylpropanesulfonic acid, acrylic acid and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, wherein the mass percentage of acrylamide: 2-acrylamide-2-methylpropanesulfonic acid: acrylic acid: dimethyldodecyl (2-acrylamidoethyl) ammonium bromide is 3-4: 0.5: 0.5: 3; The complexing agent is an aqueous solution of chromium trichloride with a mass percentage of 18%; The surfactant is a 1%-4% aqueous solution of perfluoroalkyl polyoxyethylene ether; The iron ion stabilizer is specifically a mixture of sodium isoxetine and citric acid, preferably, the mass ratio of sodium isoxetine to citric acid is 1:3; The corrosion inhibitor includes the following raw materials in a weight percentage ratio: 15%-30% of 1,4-bis((butyryloxy)-3-methylimidazoline)butene, 20%-30% of a small molecule alcohol, 2%-6% of propargyl alcohol, 5%-10% of formic acid, 0.5%-2% of an alkyl polyoxyethylene ether, and the balance being water; Among them, the structural formula of 1,4-bis((butyryloxy)-3-methylimidazoline)butene is as follows: ; The preparation method of 1,4-bis((butyryloxy)-3-methylimidazoline)butene is as follows: 40-50% N-hydroxymethylimidazoline and 50-60% acyl chloride are reacted in tetrahydrofuran with a molar ratio of 200-300% N-hydroxymethylimidazoline, 5-10% N-hydroxymethylimidazoline triethylamine is used as a catalyst, refluxed at 60-70°C for 2-3h, and then rotary evaporated to obtain a brown solid, which is then precipitated with 300-400% N-hydroxymethylimidazoline. The product is washed with methanol three times with the mass of imidazoline; the obtained product is placed in a flask, 200-300% N-hydroxymethylimidazoline mass in n-hexane is added, 10-20% N-hydroxymethylimidazoline mass in 1,4-dibromobutene is added, stirred at room temperature for 10-12 hours, filtered to obtain a precipitated product, namely 1,4-bis((butyryloxy)-3-methylimidazolinium)butene; wherein the acyl chloride is any one of butyryl chloride and hexanoyl chloride; The small molecule alcohol is a mixture of methanol and ethylene glycol, and the mass ratio of methanol to ethylene glycol is 2-5:1.

[0031] The alkyl group of the alkyl polyoxyethylene ether is either octyl or octyl; The concentration of hydrochloric acid is 12%-20%.

[0032] The present invention also discloses a preparation method of an ultra-high temperature resistant acid liquid system, comprising: adding a thickener, a corrosion inhibitor, a stabilizer and a surfactant to hydrochloric acid respectively, mixing and stirring evenly, and adding a complexing agent when injecting into a formation to obtain the ultra-high temperature resistant acid liquid system; specifically, adding hydrochloric acid into a reactor, sucking the thickener into the reactor with a suction pump under stirring, controlling the suction speed to be completely sucked in 10 minutes to 15 minutes, adding the corrosion inhibitor, stabilizer and surfactant with a liquid addition pump under stirring, stirring and mixing evenly, and adding the complexing agent with a proportional pump when injecting into the formation.

[0033] Wherein, the complexing agent is an aqueous solution of chromium trichloride with a mass percentage of 18%, the surfactant is an aqueous solution of perfluoroalkyl polyoxyethylene ether with a concentration of 1%-4%, and the stabilizer iron ion stabilizer is specifically a mixture of sodium isoxetine and citric acid. Preferably, the mass ratio of sodium isoxetine to citric acid is 1:3; The preparation method of the thickener comprises: adding 2-acrylamide-2-methylpropanesulfonic acid to water, adjusting the pH, sequentially adding acrylamide, acrylic acid and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, mixing and stirring, adding sodium sulfite and sodium thiosulfate to react after the stirring is completed, and obtaining the thickener; specifically, the preparation method comprises: adding water with a mass of 1.5 to 2 times the mass of the above-mentioned monomers (the mass of the monomers refers to the sum of the mass of the four monomers 2-acrylamide-2-methylpropanesulfonic acid, acrylamide, acrylic acid and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide) into a reactor with good thermal insulation performance, controlling the temperature at 10 to 15°C, adding 2-acrylamide-2 -methylpropanesulfonic acid, then add sodium hydroxide to adjust the pH to 7, then add acrylamide, acrylic acid and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, stir at 100-300 r / min for 10-20 minutes, maintain a nitrogen atmosphere during the stirring process, add 0.1-0.3% of the mass of acrylamide sodium sulfite and 0.2-0.4% of the mass of acrylamide sodium thiosulfate, raise the water bath temperature to 30-35°C, and maintain for 2-3 hours to obtain a thickening agent; wherein the mass percentages of acrylamide: 2-acrylamido-2-methylpropanesulfonic acid: acrylic acid: dimethyldodecyl (2-acrylamidoethyl) ammonium bromide are 3-4:0.5:0.5:3; The preparation method of the corrosion inhibitor comprises: sequentially adding a small molecule alcohol, propargyl alcohol, formic acid, 1,4-bis((butyryloxy)-3-methylimidazoline)butene, and an alkyl polyoxyethylene ether and stirring to obtain the corrosion inhibitor; wherein the alkyl group of the alkyl polyoxyethylene ether is either an octyl group or a decyl group, and the small molecule alcohol is a mixture of methanol and ethylene glycol, and the mass ratio of methanol to ethylene glycol is 2-5:1; specifically, the small molecule alcohol, propargyl alcohol, formic acid, 1,4-bis((butyryloxy)-3-methylimidazoline)butene, and the alkyl polyoxyethylene ether are sequentially added to an enameled reactor, and stirred at a speed of 3000 r / min at room temperature for 1-3 hours to obtain the corrosion inhibitor; The preparation method of 1,4-bis((butyryloxy)-3-methylimidazolinium)butene comprises: reacting N-hydroxymethylimidazoline and acyl chloride in tetrahydrofuran, rotary evaporation to obtain a product, washing the product, adding n-hexane and 1,4-dibromobutene, stirring and reacting, filtering to obtain 1,4-bis((butyryloxy)-3-methylimidazolinium)butene; specifically, the molar ratio of 40-50% N-hydroxymethylimidazoline and 50-60% acyl chloride is 40-50% N-hydroxymethylimidazoline and 50-60% acyl chloride in tetrahydrofuran with 200-300% N-hydroxymethylimidazoline by weight, and the reaction is carried out with 5-10% N-hydroxymethylimidazoline by weight. Using triethylamine as a catalyst, reflux at 60-70°C for 2-3 hours, then rotary evaporation to obtain a brown solid, which is then washed three times with 300-400% N-hydroxymethylimidazoline-based methanol. The obtained product is placed in a flask, and 200-300% N-hydroxymethylimidazoline-based n-hexane and 10-20% N-hydroxymethylimidazoline-based 1,4-dibromobutene are added. The mixture is stirred at room temperature for 10-12 hours, and filtered to obtain a precipitated product, namely 1,4-bis((butyryloxy)-3-methylimidazolinium)butene; either one of the acyl chlorides, butyryl chloride and hexanoyl chloride; The key to the acidification process is to reduce the reaction rate of acid with rock and metal pipes. The effect of temperature on the acid-rock reaction rate is exponential, and the acid-rock reaction rate is quite intense under ultra-high temperature conditions. The viscosity of the cross-linked thickener of the ultra-high temperature acid system of the present invention is large, which can effectively slow down the transmission speed of the acid and reduce the reaction rate of the acid with the rock; and the cross-linked acid system has a large cross-linking density and strong shear resistance, which can effectively cover the metal surface and avoid contact between the acid and the metal; at the same time, the ultra-high temperature corrosion inhibitor contained in the ultra-high temperature acid system of the present invention contacts the metal through the double bonds and ring structures contained therein, forming a complex structure, isolating the acid and the metal, and avoiding the metal being corroded by the acid at high temperature; further, the surfactant in the ultra-high temperature acid system of the present invention can be effectively adsorbed on the rock surface under ultra-high temperature conditions, reduce the surface tension between water and rock, and promote the return of the reacted acid to the formation.

[0034] The ultrahigh temperature resistant acid liquid system of the present invention has stable performance under ultrahigh temperature conditions and can effectively exert a retarding effect, thereby enabling the acid liquid to enter farther formations under ultrahigh temperature conditions and increasing the transformation volume. In addition, the corrosion inhibitor in the ultrahigh temperature resistant acid liquid system has a strong ability to interact with metals and can effectively protect metal pipes, thereby ensuring the safety of construction under ultrahigh temperature conditions. The low surface tension surfactant in the ultrahigh temperature resistant acid liquid system enables the residual acid liquid after construction to be quickly discharged back into the formation, thereby reducing reservoir damage caused by the retention of residual acid in the formation.

[0035] The invention also discloses an application of an ultra-high temperature resistant acid solution system, which is used for acidizing and reforming ultra-high temperature reservoirs.

[0036] Preparation Example 1 A method for preparing a thickener for an ultrahigh temperature resistant acid solution system comprises: adding 525 L of water to a reactor with good thermal insulation performance, controlling the temperature at 10°C, adding 25 kg of 2-acrylamide-2-methylpropanesulfonic acid, adding sodium hydroxide to adjust the pH to 7, then adding 150 kg of acrylamide, 25 kg of acrylic acid, and 150 kg of dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, stirring at 100 rpm for 10 minutes while maintaining a nitrogen atmosphere during the stirring process, adding 0.25 kg of sodium sulfite and 0.5 kg of sodium thiosulfate, raising the water bath temperature to 30°C, and maintaining the temperature for 2 hours to obtain the thickener.

[0037] Preparation Example 2 A method for preparing a thickener for an ultrahigh-temperature-resistant acid solution system comprises: adding 400 L of water to a reactor with good thermal insulation performance, controlling the temperature at 15°C, adding 12.5 kg of 2-acrylamide-2-methylpropanesulfonic acid, adding sodium hydroxide to adjust the pH to 7, then adding 100 kg of acrylamide, 12.5 kg of acrylic acid, and 75 kg of dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, stirring at 300 rpm for 20 minutes while maintaining a nitrogen atmosphere during the stirring process, adding 0.2 kg of sodium sulfite and 0.5 kg of sodium thiosulfate, raising the water bath temperature to 35°C, and maintaining the temperature for 3 hours to obtain the thickener.

[0038] Preparation Example 3 A method for preparing a thickener for an ultrahigh-temperature acid liquid system comprises: adding 400 L of water to a reactor with good thermal insulation performance, controlling the temperature at 13° C., adding 12.5 kg of 2-acrylamide-2-methylpropanesulfonic acid, adding sodium hydroxide to adjust the pH to 7, then adding 87.5 kg of acrylamide, 12.5 kg of acrylic acid, and 75 kg of dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, stirring at 250 r / min for 15 minutes while maintaining a nitrogen atmosphere during the stirring process, adding 0.3 kg of sodium sulfite and 0.6 kg of sodium thiosulfate, raising the water bath temperature to 33° C., and maintaining the temperature for 2.5 hours to obtain the thickener.

[0039] Preparation Example 4 A method for preparing a corrosion inhibitor for an ultrahigh temperature resistant acid solution system comprises: sequentially adding 115 L of water, 40 kg of a small molecule alcohol (methanol:ethylene glycol=2:1), 4 kg of propargyl alcohol, 10 kg of formic acid, 30 kg of 1,4-bis((butyryloxy)-3-methylimidazoline)butene, and 1 kg of an alkyl polyoxyethylene ether into an enameled reactor; and stirring the mixture at 3000 r / min for 3 hours at room temperature to obtain the corrosion inhibitor.

[0040] Preparation Example 5 A method for preparing a corrosion inhibitor for an ultrahigh temperature resistant acid solution system comprises: sequentially adding 44 L of water, 60 kg of a small molecule alcohol (methanol:ethylene glycol=2:1), 12 kg of propargyl alcohol, 20 kg of formic acid, 60 kg of 1,4-bis((butyryloxy)-3-methylimidazoline)butene, and 4 kg of an alkyl polyoxyethylene ether into an enameled reactor; and stirring the mixture at 3000 r / min at room temperature for 1 hour to obtain the corrosion inhibitor.

[0041] An ultrahigh temperature acid solution resistant system was prepared based on the thickener and corrosion inhibitor synthesized in Preparation Examples 1-5.

[0042] Example 1 A method for preparing an ultrahigh temperature resistant acid solution system comprises: adding 95.35 kg of hydrochloric acid with a concentration of 12% into a reaction kettle, sucking 0.4 kg of the thickener in Example 1 into the kettle using a suction pump while stirring, controlling the suction speed to complete the suction within 10 minutes, adding 4 kg of the corrosion inhibitor, 0.1 kg of an iron ion stabilizer, and 0.1 kg of 1% perfluoroalkyl polyoxyethylene ether in Example 5 using a liquid addition pump while stirring, stirring and mixing uniformly, and adding 0.05 kg of a complexing agent using a proportional pump when injecting into the formation.

[0043] Example 2 A method for preparing an ultrahigh temperature resistant acid solution system comprises: adding 93.3 kg of hydrochloric acid with a concentration of 15% into a reaction kettle, sucking 0.6 kg of the thickener in Example 3 into the kettle using a suction pump while stirring, controlling the suction speed to complete the suction within 12 minutes, adding 5 kg of the corrosion inhibitor, 0.2 kg of an iron ion stabilizer, and 0.2 kg of 4% perfluoroalkyl polyoxyethylene ether in Example 4 using a liquid addition pump while stirring, stirring and mixing uniformly, and adding 0.07 kg of a complexing agent using a proportional pump when injecting into the formation.

[0044] Example 3 A method for preparing an ultrahigh temperature resistant acid solution system comprises: adding 93.91 kg of hydrochloric acid with a concentration of 17% into a reaction kettle, sucking 0.5 kg of the thickener in Example 2 into the kettle using a suction pump while stirring, controlling the suction speed to complete the suction within 14 minutes, adding 5 kg of the corrosion inhibitor, 0.25 kg of an iron ion stabilizer, and 0.25 kg of 3% perfluoroalkyl polyoxyethylene ether in Example 5 using a liquid addition pump while stirring, stirring and mixing uniformly, and adding 0.09 kg of a complexing agent using a proportional pump when injecting into the formation.

[0045] Example 4 A method for preparing an ultrahigh temperature acid liquid resistant system comprises: adding 92.7 kg of hydrochloric acid with a concentration of 20% into a reaction kettle, sucking 0.6 kg of the thickener in Example 3 into the kettle using a suction pump while stirring, controlling the suction speed to complete the suction within 15 minutes, adding 6 kg of the ultrahigh temperature corrosion inhibitor, 0.3 kg of an iron ion stabilizer, and 0.3 kg of 4% perfluoroalkyl polyoxyethylene ether in Example 4 using a liquid addition pump while stirring, stirring and mixing uniformly, and adding 0.1 kg of a complexing agent using a proportional pump when injecting into the formation.

[0046] Test and Inspection The retarding and corrosion inhibition performance of the ultrahigh temperature acid solution resistant systems prepared in Examples 1-4 of the present invention at an ultrahigh temperature of 220°C were tested in accordance with the corrosion rate test method in the standard SY-T 5886-2012 "Retarding Acid Performance Evaluation Method" and SYT 5405-2019 "Performance Test Method and Evaluation Index of Corrosion Inhibitors for Acidification". The test results are shown in Table 1: Table 1: Performance test results of ultra-high temperature acid solution resistant systems prepared in Examples 1-4

[0047] It can be seen from Table 1 that the surface tension, retarding rate and corrosion rate of the ultrahigh temperature acid solution resistant systems prepared in Examples 1-4 of the present invention can meet industry standards and have retarding and corrosion inhibition performance under ultrahigh temperature conditions of 220°C.

[0048] In summary, the ultra-high temperature resistant acid liquid system of the present invention has stable performance under ultra-high temperature conditions, can effectively play a retarding role, enable the acid liquid to enter farther strata under ultra-high temperature conditions, increase the transformation volume, and it can meet the smooth construction under ultra-high temperature conditions and ensure the construction effect.

[0049] The embodiments described above are merely descriptions of preferred implementations of the present invention and are not intended to limit the scope of the present invention. Without departing from the design spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by ordinary engineering technicians in this field should fall within the scope of protection determined by the claims of the present invention.

Claims

1. A system resistant to ultra-high temperature acid solution, characterized in that: The invention comprises the following raw materials in proportion by weight: thickener 0.4%-0.6%, complexing agent 0.05%-0.1%, corrosion inhibitor 4%-6%, surfactant 0.1%-0.3%, stabilizer 0.1%-0.3%, and the balance is hydrochloric acid; The thickener is a copolymer of acrylamide, 2-acrylamido-2-methylpropanesulfonic acid, acrylic acid and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide; The corrosion inhibitor comprises the following raw materials in proportion by weight: 15%-30% of 1,4-bis((butyryloxy)-3-methylimidazoline)butene, 20%-30% of a small molecule alcohol, 2%-6% of propargyl alcohol, 5%-10% of formic acid, 0.5%-2% of an alkyl polyoxyethylene ether, and the balance being water.

2. The ultrahigh temperature acid solution resistant system according to claim 1, characterized in that: The mass percentages of acrylamide: 2-acrylamide-2-methylpropanesulfonic acid: acrylic acid: dimethyldodecyl (2-acrylamidoethyl) ammonium bromide are 3-4: 0.5: 0.5:

3.

3. The ultrahigh temperature acid solution resistant system according to claim 1, characterized in that: The complexing agent is a chromium trichloride aqueous solution, the surfactant is a perfluoroalkyl polyoxyethylene ether aqueous solution, and the stabilizer is a mixture of sodium isoxadiazine and citric acid.

4. The ultrahigh temperature acid solution resistant system according to claim 1, characterized in that: The small molecule alcohol is a mixture of methanol and ethylene glycol, and the mass ratio of the methanol to ethylene glycol is 2-5:

1.

5. The ultrahigh temperature acid solution resistant system according to claim 1, characterized in that: The alkyl group of the alkyl polyoxyethylene ether is any one of octyl group and octyl group.

6. A method for preparing an ultrahigh temperature acid solution resistant system, characterized in that: include: Adding a thickener, a corrosion inhibitor, a stabilizer and a surfactant to the hydrochloric acid respectively, mixing and stirring evenly, and adding a complexing agent when injecting into the formation to obtain an ultra-high temperature resistant acid solution system; The preparation method of the thickener comprises: adding 2-acrylamide-2-methylpropanesulfonic acid to water, adjusting the pH, and then sequentially adding acrylamide, acrylic acid, and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, mixing, and reacting to obtain the thickener; The preparation method of the corrosion inhibitor comprises: sequentially adding a small molecule alcohol, propargyl alcohol, formic acid, 1,4-bis((butyryloxy)-3-methylimidazoline)butene and an alkyl polyoxyethylene ether and stirring to obtain the corrosion inhibitor.

7. The method for preparing an ultrahigh temperature acid solution resistant system according to claim 6, wherein: The preparation method of the thickener comprises: adding 2-acrylamide-2-methylpropanesulfonic acid to water, adjusting the pH, sequentially adding acrylamide, acrylic acid, and dimethyldodecyl (2-acrylamidoethyl) ammonium bromide, mixing and stirring, and adding sodium sulfite and sodium thiosulfate after stirring to react and obtain the thickener.

8. The method for preparing an ultrahigh temperature acid solution resistant system according to claim 6 or 7, characterized in that: The mass percentages of acrylamide: 2-acrylamide-2-methylpropanesulfonic acid: acrylic acid: dimethyldodecyl (2-acrylamidoethyl) ammonium bromide are 3-4: 0.5: 0.5:

3.

9. The method for preparing an ultrahigh temperature acid solution resistant system according to claim 6, wherein: The preparation method of 1,4-bis((butyryloxy)-3-methylimidazolinium)butene comprises: reacting N-hydroxymethylimidazoline and acyl chloride in tetrahydrofuran, rotary evaporation to obtain a product, washing the product, adding n-hexane and 1,4-dibromobutene, stirring for reaction, and filtering to obtain 1,4-bis((butyryloxy)-3-methylimidazolinium)butene.

10. The method for preparing an ultrahigh temperature acid solution resistant system according to claim 9, wherein: The acyl chloride is any one of butyryl chloride and hexanoyl chloride.

11. The method for preparing an ultrahigh temperature acid solution resistant system according to claim 6, wherein: The alkyl group of the alkyl polyoxyethylene ether is any one of octyl group and octyl group, the small molecule alcohol is a mixture of methanol and ethylene glycol, and the mass ratio of methanol to ethylene glycol is 2-5:

1.

12. The method for preparing an ultrahigh temperature acid solution resistant system according to claim 6, wherein: The complexing agent is a chromium trichloride aqueous solution, the surfactant is a perfluoroalkyl polyoxyethylene ether aqueous solution, and the stabilizer is a mixture of sodium isoxadiazine and citric acid.

13. Use of the ultrahigh temperature acid solution resistant system according to any one of claims 1 to 5, characterized in that: It is used for acidizing transformation of ultra-high temperature reservoirs.

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