A low-loss acidic slickwater system for fracturing and preparation method thereof

Abstract

The invention discloses a low-loss acidic slick water system for fracturing and a preparation method thereof, and belongs to the technical field of slick water for fracturing fluid. The slick water is measured by weight, and the raw materials include 3-5 parts of reaction acid, 0.2-0.4 parts of drag reducer, 0.4-0.6 parts of clay stabilizer, 0.2-0.3 parts of drainage aid, and 94-96 parts of water. In the slick water system of the present invention, hydrazine hydrate and copper sulfate are used as reaction acids, which can avoid direct contact between the acid solution and the injection well pipe wall, thereby avoiding the pipeline from being corroded by the acid solution. As the formation temperature gradually increases, hydrazine hydrate and copper sulfate undergo a reduction reaction, and the generated sulfuric acid can corrode the cracks, and copper and nitrogen can reduce the filtration of fracturing fluid to the rock wall, thereby improving the utilization efficiency of the fracturing system. The slick water system for fracturing has the multifunctional functions of drag reduction, corrosion, crack formation, anti-swelling and sand carrying, and has broad application prospects.

Description

Technical Field

[0001] The invention belongs to the technical field of slick water fracturing fluid, and in particular relates to a low-filtration-loss acidic slick water system for fracturing and a preparation method thereof. Background Art

[0002] Among the reserves of oil and gas resources, unconventional oil and gas resources account for a large proportion, which mainly include shale oil and gas and tight oil. Among them, shale oil and gas reservoirs have the characteristics of ultra-low porosity and ultra-low permeability, and need to be developed using fracturing and production-increasing technology. Among the current transformation measures for carbonate shale reservoirs, acidic slick water fracturing fluid is generally used. The acid can dissolve the carbonate core, improve its pore structure, and improve the conductivity of the supporting fractures, thereby improving the production-increasing effect of fracturing.

[0003] At present, acidic slick water fracturing fluid generally adds a certain amount of hydrochloric acid, formic acid or acetic acid to the slick water fracturing system to etch the reservoir cracks. In order to obtain higher permeability, the concentration of the acid fluid is sometimes increased during the production process. However, when the concentration of the acid is greatly increased, the corrosion to the injection well pipe will be greatly increased. The corrosion will cause the pipe wall to become thinner, and in severe cases, perforation and leakage will occur. And because the acid reacts with the formation during the fracturing process, if the filtration loss of the fracturing fluid is too large, the efficiency of the fracturing fluid will be reduced, and it may even cause reservoir damage. Summary of the invention

[0004] The purpose of the present invention is to overcome the shortcomings of the above-mentioned prior art and provide a low-loss acidic slick water system for fracturing and a preparation method thereof, so as to solve the problem in the prior art that the acid liquid will directly react with the formation during the fracturing process. If the filtration loss of the fracturing fluid is too large, the efficiency of the fracturing fluid is easily reduced, causing reservoir damage.

[0005] In order to achieve the above object, the present invention adopts the following technical solutions: A low-loss acidic slick water system for fracturing, wherein the raw materials of the low-loss acidic slick water for fracturing include, by weight, 3-5 parts of reaction acid, 0.2-0.4 parts of drag reducer, 0.4-0.6 parts of clay stabilizer, 0.2-0.3 parts of drainage aid, and 94-96 parts of water; the reaction acid is a mixture of hydrazine hydrate and copper sulfate; The mass ratio of hydrazine hydrate to copper sulfate is 1:(1-1.2); The drag reducer is cationic polyacrylamide; The clay stabilizer is a quaternary ammonium salt surfactant; The drainage aid is a mixture of sodium perfluorononenyloxybenzenesulfonate and alkanolamide.

[0006] A further improvement of the present invention is: Preferably, the relative molecular weight of the cationic polyacrylamide is 6 million to 12 million; the present invention adopts cationic polyacrylamide with a relative molecular weight of 6 million to 12 million, and the molecular weight of polyacrylamide belongs to the medium to high range within this range. The polymer chain of high molecular weight is longer, thereby providing better drag reduction effect in the fluid; the higher drag reduction effect is conducive to the sufficient corrosion cracks of sulfuric acid generated by the reaction of hydrazine hydrate and copper sulfate.

[0007] Preferably, the quaternary ammonium salt surfactant is dodecyl trimethyl ammonium chloride, lauryl amide propyl betaine, dodecyl dimethyl benzyl ammonium chloride, dodecyl dimethyl (3-sulfopropyl) ammonium hydroxide inner salt or coconut oil alkyl dimethyl ethyl benzyl chloride quaternary ammonium salt. Quaternary ammonium salt surfactants can reduce the surface tension of slippery water and the oil-water interfacial tension, thereby reducing the resistance in the flow process, improving the fluidity of the fluid, and helping to improve the injection efficiency and reduce energy consumption. And quaternary ammonium salt surfactants can still maintain good stability under high temperature conditions, can continuously break and reorganize during high-speed shearing, and show excellent drag reduction and heat and shear resistance.

[0008] Preferably, the mass ratio of sodium perfluorononenyloxybenzenesulfonate and alkanolamide in the drainage agent is 1:(8-10). Sodium perfluorononenyloxybenzenesulfonate and alkanolamide as drainage agents can increase the recovery rate of crude oil, improve the flow properties of oil-water mixture, and have good heat and shear resistance and environmental protection. Their composite system can play a synergistic role in hydraulic fracturing and further improve the operation efficiency.

[0009] Preferably, during the application of the low-loss acidic slick water for fracturing, when the temperature of the well pipe is above 80°C, the dissolution rate of the low-loss acidic slick water for fracturing on rock cuttings is ≥30%. This dissolution effect can increase the complexity of the fractures, thereby improving the permeability of the reservoir and the recovery rate of oil and gas.

[0010] During the application of the low-loss acidic slick water for fracturing, when the temperature of the well pipe is 120°C, the static loss coefficient of the low-loss acidic slick water for fracturing is 0.141×10 -3 m / min 1 / 2 .

[0011] A method for preparing a low-loss acidic slick water system for fracturing comprises the following steps: S1, mixing hydrazine hydrate and copper sulfate in a mass ratio of 1:(1-1.2) to prepare a reaction acid; S2, mixing sodium perfluorononenyloxybenzenesulfonate and alkanolamide to prepare a drainage aid; S3, by mass fraction, 3-5 parts of reaction acid, 0.2-0.4 parts of drag reducer, 0.4-0.6 parts of clay stabilizer, 0.2-0.3 parts of drainage aid and 94-96 parts of water are mixed and stirred to obtain low-loss acidic slick water for fracturing; The drag reducer is cationic polyacrylamide; The clay stabilizer is a quaternary ammonium salt surfactant.

[0012] Preferably, in S2, the mixing mass ratio of the sodium perfluorononenyloxybenzenesulfonate and the alkanolamide is 1:(8-10).

[0013] Preferably, in S3, the relative molecular weight of the cationic polyacrylamide is 6 million to 12 million.

[0014] Preferably, in S3, the quaternary ammonium salt surfactant is dodecyltrimethylammonium chloride, laurylamidopropyl betaine, dodecyldimethylbenzylammonium chloride, dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt or coconut oil alkyldimethylethylbenzyl chloride quaternary ammonium salt.

[0015] Compared with the prior art, the present invention has the following beneficial effects: The present invention provides a low-loss acidic slick water system for fracturing and a preparation method thereof, wherein hydrazine hydrate and copper sulfate are used as reaction acids, combined with a drag reducer, a clay stabilizer, and a drainage aid to form a low-loss acidic slick water system. In the slick water system, hydrazine hydrate and copper sulfate are used as reaction acids in a mass ratio of 1: (1-1.2). As the slick water flows into the depth of the well pipe and as the ambient temperature rises, hydrazine hydrate and copper sulfate react to generate nitrogen, copper ions, and sulfuric acid, which can avoid direct contact between the acid and the wall of the injection well pipe and avoid corrosion of the pipeline by the acid. As the formation temperature gradually rises, hydrazine hydrate and copper sulfate undergo a reduction reaction, and the generated sulfuric acid can corrode the cracks. The copper element and nitrogen can reduce the loss of the fracturing fluid to the rock wall, thereby improving the utilization efficiency of the fracturing system. The low-loss acidic slick water system for fracturing provided by the present invention can not only utilize acid corrosion to create cracks, but also reduce the filtration loss of the fracturing system and improve its utilization efficiency. It is a multifunctional slick water system for fracturing with drag reduction, dissolution, crack creation, anti-swelling and sand carrying, and has broad application prospects.

[0016] The hydrazine hydrate, copper sulfate, cationic polyacrylamide, quaternary ammonium salt surfactant, sodium perfluorononenyloxybenzenesulfonate, alkanolamide and water used in the low-loss acidic slick water system for fracturing provided by the present invention have good compatibility, and the static loss coefficient of the slick water is 0.141×10 -3 m / min 1 / 2 . BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The dissolution rate of the acidic slippery water system prepared in Example 4 at different temperatures; Figure 2 The static filtration coefficient of the acidic slick water system prepared in Example 4 at different temperatures. DETAILED DESCRIPTION

[0018] In order to enable those skilled in the art to understand the characteristics and effects of the present invention, the following is a general description and definition of the terms and expressions mentioned in the specification and claims. Unless otherwise specified, all technical and scientific terms used in the text are the common meanings understood by those skilled in the art for the present invention. In the event of a conflict, the definition in this specification shall prevail.

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

[0020] In this document, all characteristics such as values, quantities, contents and concentrations defined in the form of numerical ranges or percentage ranges are for simplicity and convenience only. Accordingly, the description of numerical ranges or percentage ranges should be regarded as In this document, unless otherwise specified, “includes,” “including,” “contains,” “has,” or similar terms cover the meanings of “consisting of” and “mainly consisting of,” for example, “A includes a” covers the meanings of “A includes a and other” and “A only includes a.”

[0021] In this document, in order to make the description concise, not all possible combinations of various technical features in various embodiments or examples are described. Therefore, as long as there is no contradiction in the combination of these technical features, the various technical features in various embodiments or examples can be combined arbitrarily, and all possible combinations should be considered to be within the scope of this specification.

[0022] The present invention will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are only used to illustrate the present invention and are not intended to limit the scope of the present invention. In addition, it should be understood that after reading the content taught by the present invention, those skilled in the art can make various changes or modifications to the present invention, and these equivalent forms fall within the scope limited by the appended claims of the application equally.

[0023] The following examples use conventional instruments and equipment in the art. The experimental methods in the following examples where specific conditions are not specified are usually carried out under conventional conditions or under conditions recommended by the manufacturer. The various raw materials used in the following examples are conventional commercial products unless otherwise specified, and their specifications are conventional specifications in the art. In the specification of the present invention and the following examples, unless otherwise specified, "%" means weight percentage, "part" means weight part, and ratio means weight ratio.

[0024] The invention provides a low-loss acidic slick water system for fracturing. The raw materials of the low-loss acidic slick water system for fracturing include, by weight, 3 to 5 parts of reaction acid, 0.2 to 0.4 parts of drag reducer, 0.4 to 0.6 parts of clay stabilizer, 0.2 to 0.3 parts of drainage aid, and 94 to 96 parts of water.

[0025] The present invention uses hydrazine hydrate and copper sulfate as reaction acids. As the formation temperature gradually increases, when the slippery water flows into the depth of the well pipe, as the ambient temperature increases, the hydrazine hydrate and copper sulfate react to generate nitrogen, copper ions and sulfuric acid. The nitrogen and copper ions generated in the reaction process can reduce the filtration loss of the fracturing fluid to the rock wall, while avoiding direct contact between the acid and the injection well pipe wall, thereby reducing the risk of the pipeline being corroded by the acid. The low-loss acid slippery water system for fracturing provided by the present invention can not only use acid corrosion to create cracks, but also reduce the filtration loss of the fracturing system and improve its utilization efficiency. It is a slippery water system for fracturing with multiple functions such as drag reduction, dissolution, crack creation, anti-swelling and sand carrying. Due to its versatility and ability to improve fracturing efficiency, the low-loss acid slippery water system for fracturing of the present invention has broad application prospects.

[0026] The reaction process is shown in the following formula.

[0027]

[0028] The present invention also provides a method for preparing the above-mentioned low-loss acidic slick water system for fracturing, wherein reaction acid, drag reducer, clay stabilizer, drainage aid and water are weighed according to a formula, mixed and stirred to obtain the low-loss acidic slick water system for fracturing.

[0029] In the specific implementation process, the reaction acid is a mixture of hydrazine hydrate and copper sulfate, and the mass ratio of hydrazine hydrate to copper sulfate is 1: (1~1.2).

[0030] In the specific implementation process, the drag reducer is cationic polyacrylamide, and the relative molecular weight of the cationic polyacrylamide is 6 million to 12 million. Cationic polyacrylamide with a relative molecular weight of 6 million to 12 million is used. The molecular weight of polyacrylamide belongs to the medium to high range within this range, and the polymer chain of high molecular weight is longer, thereby providing better drag reduction effect in the fluid; the higher drag reduction effect is conducive to the sulfuric acid generated by the reaction of hydrazine hydrate and copper sulfate to fully corrode the cracks.

[0031] In the specific implementation process, the clay stabilizer is a quaternary ammonium salt surfactant, specifically dodecyl trimethyl ammonium chloride, lauryl amide propyl betaine, dodecyl dimethyl benzyl ammonium chloride, dodecyl dimethyl (3-sulfopropyl) ammonium hydroxide inner salt or coconut oil alkyl dimethyl ethyl benzyl chloride quaternary ammonium salt. Quaternary ammonium salt surfactants can reduce the surface tension of slippery water and the oil-water interfacial tension, thereby reducing the resistance during the flow process, improving the fluidity of the fluid, and helping to improve the injection efficiency and reduce energy consumption. And quaternary ammonium salt surfactants can still maintain good stability under high temperature conditions, can continuously break and reorganize during high-speed shearing, and show excellent drag reduction and temperature and shear resistance.

[0032] In the specific implementation process, the drainage agent is compounded by sodium perfluorononenyloxybenzenesulfonate and alkanolamide, and the mass ratio of sodium perfluorononenyloxybenzenesulfonate to alkanolamide is 1: (8-10). Sodium perfluorononenyloxybenzenesulfonate and alkanolamide as drainage agents can improve the recovery rate of crude oil, improve the flow properties of oil-water mixture, and have good heat resistance and shear resistance and environmental protection. Their composite system can play a synergistic role in hydraulic fracturing and further improve the operation efficiency.

[0033] The present invention provides a low-loss acidic slick water system for fracturing, and the specific preparation steps are as follows: S1: Mix a certain amount of hydrazine hydrate and copper sulfate to prepare a reaction acid, wherein the mass ratio of hydrazine hydrate to copper sulfate is 1: (1-1.2).

[0034] S2: A certain amount of sodium perfluorononenyloxybenzene sulfonate and alkanolamide are mixed to prepare a drainage agent, wherein the mass ratio of sodium perfluorononenyloxybenzene sulfonate to alkanolamide is 1:(8-10).

[0035] S3: Mix and stir a certain amount of reaction acid, drag reducer, clay stabilizer, drainage aid and water until uniform, so as to obtain the low-loss acidic slick water system for fracturing. The raw materials of the low-loss acidic slick water system for fracturing include 3-5 parts of reaction acid, 0.2-0.4 parts of drag reducer, 0.4-0.6 parts of clay stabilizer, 0.2-0.3 parts of drainage aid and 94-96 parts of water, which is 100 parts in total, in parts by weight.

[0036] The drag reducer is cationic polyacrylamide, and the relative molecular weight of cationic polyacrylamide is 6 million to 12 million. The clay stabilizer is a quaternary ammonium surfactant, specifically dodecyl trimethyl ammonium chloride, lauryl amide propyl betaine, dodecyl dimethyl benzyl ammonium chloride, dodecyl dimethyl (3-sulfopropyl) ammonium hydroxide inner salt or coconut oil alkyl dimethyl ethyl benzyl chloride quaternary ammonium salt. Quaternary ammonium surfactants can effectively prevent the expansion and dispersion of clay minerals. Through electrostatic adsorption with the negative charge on the surface of the clay, a protective film is formed, thereby reducing the hydration expansion of the clay particles and maintaining the permeability of the reservoir. Quaternary ammonium surfactants can still maintain good stability under high temperature conditions, which is beneficial to oil and gas production in deep wells and high temperature environments, because these environmental conditions place higher requirements on the stability of chemical agents. In addition, quaternary ammonium surfactants usually have better biodegradability, less impact on the environment, and meet current environmental protection requirements.

[0037] The present invention will be further described below in conjunction with specific embodiments: Example 1 S1: Mix 10 g of hydrazine hydrate and 10 g of copper sulfate to prepare the reaction acid.

[0038] S2: 2 g of sodium perfluorononenyloxybenzene sulfonate and 16 g of alkanolamide were mixed to prepare a drainage aid.

[0039] S3: 3 g of the reaction acid prepared in S1, 0.2 g of cationic polyacrylamide, 0.4 g of dodecyltrimethylammonium chloride, 0.2 g of the drainage agent prepared in S2 and 94 g of water are mixed and stirred to obtain the low-loss acidic slick water system for fracturing; in this embodiment, the relative molecular weight of the cationic polyacrylamide is 6 million to 12 million.

[0040] Example 2 S1: Mix 10 g of hydrazine hydrate and 12 g of copper sulfate to prepare the reaction acid.

[0041] S2: 2 g of sodium perfluorononenyloxybenzene sulfonate and 20 g of alkanolamide were mixed to prepare a drainage aid.

[0042] S3: 5 g of the reaction acid prepared in S1, 0.4 g of cationic polyacrylamide, 0.6 g of lauryl amide propyl betaine, 0.3 g of the drainage agent prepared in S2 and 96 g of water are mixed and stirred to obtain the low filtration loss acidic slick water system for fracturing.

[0043] Example 3 S1: Mix 10 g of hydrazine hydrate and 11 g of copper sulfate to prepare the reaction acid.

[0044] S2: 2 g of sodium perfluorononenyloxybenzene sulfonate and 18 g of alkanolamide were mixed to prepare a drainage aid.

[0045] S3: 3 g of the reaction acid prepared in S1, 0.3 g of cationic polyacrylamide, 0.5 g of dodecyldimethylbenzyl ammonium chloride, 0.2 g of the drainage agent prepared in S2 and 95 g of water are mixed and stirred to obtain the low-loss acidic slick water system for fracturing.

[0046] Example 4 S1: Mix 10 g of hydrazine hydrate and 11 g of copper sulfate to prepare the reaction acid.

[0047] S2: 2 g of sodium perfluorononenyloxybenzene sulfonate and 20 g of alkanolamide were mixed to prepare a drainage aid.

[0048] S3: 4 g of the reaction acid prepared in S1, 0.2 g of cationic polyacrylamide, 0.5 g of dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt, 0.3 g of the drainage agent prepared in S2 and 94 g of water are mixed and stirred to obtain the low-loss acidic slick water system for fracturing.

[0049] Example 5 S1: Mix 10 g of hydrazine hydrate and 10 g of copper sulfate to prepare the reaction acid.

[0050] S2: 2 g of sodium perfluorononenyloxybenzene sulfonate and 20 g of alkanolamide were mixed to prepare a drainage aid.

[0051] S3: 3 g of the reaction acid prepared in S1, 0.4 g of cationic polyacrylamide, 0.4 g of coconut oil alkyl dimethyl ethyl benzyl chloride quaternary ammonium salt, 0.3 g of the drainage agent prepared in S2 and 96 g of water are mixed and stirred to obtain the low filtration loss acidic slick water system for fracturing.

[0052] Example 6 S1: Mix 10 g of hydrazine hydrate and 12 g of copper sulfate to prepare the reaction acid.

[0053] S2: 2 g of sodium perfluorononenyloxybenzene sulfonate and 17 g of alkanolamide were mixed to prepare a drainage aid.

[0054] S3: 5 g of the reaction acid prepared in S1, 0.3 g of cationic polyacrylamide, 0.6 g of dodecyltrimethylammonium chloride, 0.3 g of the drainage agent prepared in S2 and 95 g of water are mixed and stirred to obtain the low-loss acidic slick water system for fracturing.

[0055] In order to evaluate the dissolution effect of the low-loss acidic slick water system for fracturing, according to the petroleum and natural gas industry standard SY / T 5358-2002 "Reservoir Sensitivity Flow Test Method", the cuttings were placed in the acidic slick water system prepared in Example 4, and then fully reacted at different temperatures for 2 h, and the dissolution rate under different hydrochloric acid concentrations was calculated. The results are as follows: Figure 1 As shown. Figure 1 It can be seen that when the temperature is low, the acidic slick water system has a low dissolution rate for rock cuttings. When the temperature reaches above 80°C, the dissolution rate for rock cuttings reaches more than 30%, indicating that the acidic slick water system prepared in Example 4 can effectively increase the permeability of fractures. When the temperature is above 80°C, the dissolution rate for rock cuttings in other examples is greater than 30%.

[0056] In order to evaluate the filtration performance of the low-loss acidic slick water system for fracturing, according to the evaluation part of "static filtration" in the petroleum and natural gas industry standard SY / T 5107-2016 "Water-based fracturing fluid performance evaluation method", a high-temperature and high-pressure filter loss instrument was used to evaluate the filtration performance of the acidic slick water system prepared in Example 4 at different temperatures. The results are as follows: Figure 2 As shown. Figure 2 It can be seen that the static filtration coefficient of the acidic slick water system gradually increases with the increase of temperature. When the temperature reaches 120 °C, the static filtration coefficient of the fracturing fluid system is only 0.141×10 -3 m / min 1 / 2 , which is less than the reference value of 1.0×10 -3 m / min 1 / 2 The static filtration coefficients of other embodiments are shown in Table 1 below, which shows that the developed acidic slick water system has good static filtration performance, and further shows that under high temperature conditions, the filtration performance of the fracturing fluid is effectively controlled to prevent the reservoir from being damaged.

[0057] Table 1 Static filtration coefficient of Examples 1-5

[0058] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A low-loss acidic slick water system for fracturing, characterized in that: The raw materials of the low-loss acidic slick water for fracturing include 3-5 parts of reaction acid, 0.2-0.4 parts of drag reducer, 0.4-0.6 parts of clay stabilizer, 0.2-0.3 parts of drainage aid, and 94-96 parts of water in parts by weight; the reaction acid is a mixture of hydrazine hydrate and copper sulfate; The mass ratio of hydrazine hydrate to copper sulfate is 1:(1-1.2); The drag reducer is cationic polyacrylamide; The clay stabilizer is a quaternary ammonium salt surfactant; The drainage aid is a mixture of sodium perfluorononenyloxybenzenesulfonate and alkanolamide.

2. A low-loss acidic slick water system for fracturing according to claim 1, characterized in that: The relative molecular weight of the cationic polyacrylamide is 6 million to 12 million.

3. A low-loss acidic slickwater system for fracturing according to claim 1, characterized in that: The quaternary ammonium salt surfactant is dodecyltrimethylammonium chloride, laurylamidopropyl betaine, dodecyldimethylbenzylammonium chloride, dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt or coconut oil alkyldimethylethylbenzyl chloride quaternary ammonium salt.

4. A low-loss acidic slick water system for fracturing according to claim 1, characterized in that: The mass ratio of sodium perfluorononenyloxybenzenesulfonate to alkanolamide in the drainage agent is 1:(8-10).

5. A low-loss acidic slickwater system for fracturing according to claim 1, characterized in that: During the application of the low-loss acidic slick water for fracturing, when the temperature of the well pipe is above 80° C., the dissolution rate of the low-loss acidic slick water for fracturing on rock cuttings is ≥30%.

6. A method for preparing a low-loss acidic slick water system for fracturing, characterized in that: The following steps are involved: S1, mixing hydrazine hydrate and copper sulfate in a mass ratio of 1:(1-1.2) to prepare a reaction acid; S2, mixing sodium perfluorononenyloxybenzenesulfonate and alkanolamide to prepare a drainage aid; S3, by mass fraction, 3-5 parts of reaction acid, 0.2-0.4 parts of drag reducer, 0.4-0.6 parts of clay stabilizer, 0.2-0.3 parts of drainage aid and 94-96 parts of water are mixed and stirred to obtain low-loss acidic slick water for fracturing; The drag reducer is cationic polyacrylamide; The clay stabilizer is a quaternary ammonium salt surfactant.

7. The method for preparing a low-loss acidic slick water system for fracturing according to claim 6, characterized in that: In S2, the mixing mass ratio of the sodium perfluorononenyloxybenzenesulfonate and the alkanolamide is 1:(8-10).

8. The method for preparing a low-loss acidic slickwater system for fracturing according to claim 6, characterized in that: In S3, the relative molecular weight of the cationic polyacrylamide is 6 million to 12 million.

9. The method for preparing a low-loss acidic slickwater system for fracturing according to claim 6, characterized in that: In S3, the quaternary ammonium salt surfactant is dodecyltrimethylammonium chloride, laurylamidopropyl betaine, dodecyldimethylbenzylammonium chloride, dodecyldimethyl (3-sulfopropyl) ammonium hydroxide inner salt or coconut oil alkyldimethylethylbenzyl chloride quaternary ammonium salt.

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