Micro-slit net interface modified far-end strong sand-carrying fracturing fluid and preparation method thereof

Abstract

The application discloses a micro-slit net interface modified far-end strong sand-carrying fracturing fluid and a preparation method thereof, and relates to the technical field of oil and gas field exploitation. The fracturing fluid comprises, in terms of weight parts, 20-50 parts of low-molecular-weight polyacrylamide, 10-30 parts of polyhydroxyethyl acrylamide, 30-75 parts of diethylene glycol ethyl ether acetate, 2-10 parts of fumed silica, 3-12 parts of a titanate coupling agent, 2-7 parts of a gemini cationic surfactant, 2-7 parts of an alkyl polyoxyethylene ether, and 2-7 parts of an intermediate S. The intermediate S comprises, in terms of weight parts, 10-25 parts of zirconium oxychloride, 5-25 parts of sodium lactate, and 65-85 parts of diethylene glycol ethyl ether acetate. The preparation comprises the following steps: S1, preparation of the intermediate S; and S2, preparation of the finished product R. The fracturing fluid has the characteristics of high resistance reduction, low damage and strong sand carrying, and can realize gas guiding and oil increasing by modifying the surface characteristics of reservoir rocks, thereby improving the yield of oil and gas wells.

Description

Technical Field

[0001] This invention relates to the field of oil and gas field development technology, specifically to a micro-fractured mesh interface modified distal strong sand-carrying fracturing fluid and its preparation method. Background Technology

[0002] With the oil and gas industry's in-depth research on unconventional shale fracturing methods, creating a larger and more complex fracture network has become an important reservoir stimulation objective and a key means of increasing oil and gas production.

[0003] In many shale fracturing processes, numerous secondary fracture networks based on induced and natural fractures emerge. These secondary fracture networks can absorb up to 90% of the total fluid volume during hydraulic fracturing. The white oil and surfactants in traditional oil-based fracturing fluid systems can easily clog and damage micro-fractures. Simultaneously, due to flow attenuation of the fracturing fluid at the distal ends and branch fractures of micro-fractures, proppant carrying capacity decreases, and proppant gradually settles, making it difficult to effectively penetrate deep into the fractures. Under in-situ stress, due to the lack of effective support, branch fractures gradually close, and micro-fractures are further clogged by harmful organic components from the broken gel residue of the fracturing fluid, severely impacting production growth and stability. Current research and reports on these issues primarily focus on reducing damage from fracturing fluid rupture and increasing the proppant-carrying capacity of polymer fracturing fluids (e.g., patents CN105219372B, CN103756664A), often neglecting the modification of reservoir rock surface properties. Because untreated rocks are weakly hydrophilic, water in the reservoir easily adheres to fractures and rock surfaces, clogging the channels for crude oil and natural gas discharge. Simultaneously, due to the Jamin effect and capillary action, the flow resistance of hydrophobic crude oil and natural gas in the pores increases, further reducing the actual recovery rate. Therefore, adopting comprehensive methods to modify and optimize rock wettability, while simultaneously improving the far-end proppant-carrying capacity of fracturing fluids and reducing the damage caused by fracturing fluid rupture, represents a technological development trend for solving these problems. Summary of the Invention

[0004] This invention provides a micro-fractured mesh interface-modified distal strong sand-carrying fracturing fluid and its preparation method. It not only has the characteristics of high drag reduction, low damage, and strong sand carrying capacity, but also can achieve gas conduction and oil enhancement by modifying the surface characteristics of reservoir rocks, thereby increasing the production of oil and gas wells.

[0005] This invention is achieved through the following technical solution: a micro-fracture interface modified distal-end strong sand-carrying fracturing fluid, comprising, by weight, 20-50 parts low molecular weight polyacrylamide, 10-30 parts polyhydroxyethyl acrylamide, 30-75 parts diethylene glycol ethyl ether acetate, 2-10 parts fumed silica, 3-12 parts titanate coupling agent, 2-7 parts gemini cationic surfactant, 2-7 parts alkyl polyoxyethylene ether, and 2-7 parts intermediate S; wherein intermediate S, by weight, comprises 10-25 parts zirconium oxychloride, 5-25 parts sodium lactate, and 65-85 parts diethylene glycol ethyl ether acetate.

[0006] Furthermore, the effective content of the sodium lactate is >99%.

[0007] Furthermore, the low molecular weight polyacrylamide has a molecular weight of 3-8 million, and the polyhydroxyethyl acrylamide has a molecular weight of 5-30 million.

[0008] Furthermore, the titanate coupling agent is one or more of isopropyltris(dioctylpyrophosphate)titanate, isopropyl triisostearate titanate, and bis(triethanolamine) diisopropyltitanate, and the geminal cationic surfactant is one or more of bis(dodecyl)dimethylammonium chloride, bis(hexadecyl)dimethylammonium chloride, and bis(tetradecyl)dimethylammonium chloride.

[0009] Furthermore, the alkyl polyoxyethylene ether is one or more of octadecylamine polyoxyethylene ether, dodecylamine polyoxyethylene ether, and hexadecylamine polyoxyethylene ether.

[0010] A method for preparing a micro-fracture mesh interface-modified distal-end strong sand-carrying fracturing fluid includes the following steps:

[0011] Preparation of intermediate S1: The preparation of intermediate S includes the following steps:

[0012] A1: By weight, 5-25 parts of sodium lactate and 10-25 parts of zirconium oxychloride are mixed and added to 65-85 parts of diethylene glycol ethyl ether acetate. The mixture is heated to 50±5℃ under stirring and reacted for 2-3 hours to obtain intermediate A.

[0013] A2: Add pH adjuster to intermediate A several times, and take a 0.1% aqueous solution of intermediate A every 30 minutes to measure the pH value until the pH value is 4-5. Keep the material temperature constant at 50±5℃ and react for 4-5 hours. After cooling to room temperature, intermediate S is obtained. The weight ratio of pH adjuster to intermediate A added each time is 1:1000.

[0014] Preparation of finished product R (S2): The preparation of finished product R includes the following steps:

[0015] B1: Low molecular weight polyacrylamide, polyhydroxyethyl acrylamide, and fumed silica are added to diethylene glycol ethyl ether acetate in a certain proportion. The mixture is stirred evenly under high speed and allowed to stand for 1-1.5 hours to obtain intermediate B.

[0016] B2: Add titanate coupling agent and gemini cationic surfactant to intermediate B and stir at high speed until homogeneous. Let stand for 1-1.5 hours to obtain intermediate C.

[0017] B3: Add alkyl polyoxyethylene ethers to intermediate C and stir at high speed until homogeneous. Let stand for 1-2 hours to obtain intermediate D.

[0018] B4: Add intermediate S to intermediate D and mix evenly under high-speed stirring to obtain finished product R;

[0019] The amounts of the above reactants added, by weight, are: 20-50 parts low molecular weight polyacrylamide, 10-30 parts polyhydroxyethyl acrylamide, 30-75 parts diethylene glycol ethyl ether acetate, 2-10 parts fumed silica, 3-12 parts titanate coupling agent, 2-7 parts geminolytic surfactant, 2-7 parts alkyl polyoxyethylene ethers, and 2-7 parts intermediate S;

[0020] Preparation of S3 strong proppant-carrying fracturing fluid: The finished product R is prepared into a solution with a content of 0.1wt% to obtain the micro-fracture interface modified low-damage distal enhanced proppant-carrying fracturing fluid.

[0021] Furthermore, in step A2, the pH adjuster is an ethanol solution of diethanolamine with a mass fraction of 10.0 wt%.

[0022] Furthermore, the stirring speed in step A1 is 300-1000 r / min.

[0023] Furthermore, in the preparation step of the S2 product R, the high-speed stirring speed is 1500-2500 r / min.

[0024] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0025] 1. The present invention discloses a micro-slit mesh interface-modified distal strong sand-carrying fracturing fluid and its preparation method. A titanate coupling agent is added, which is used to form a hydrophobic film on the proppant and fracture surface by hydrolysis and adsorption with hydroxyl groups on the rock surface. At the same time, the mesh modification component is attached to the proppant and fracture surface through intermolecular forces.

[0026] 2. This invention discloses a micro-fracture mesh interface-modified distal strong sand-carrying fracturing fluid and its preparation method. Gemini cationic surfactants are used as modifying components to hydrophobically modify the reservoir rock, making it difficult for water in the reservoir to be adsorbed onto the rock and fracture base surface, thus creating a channel conducive to oil and gas production. Simultaneously, some natural gas exists in the form of adsorbed gas during extraction. The hydrophobic treatment of the pores, along with the discharge of formation water from the reservoir, and influenced by the pressure differential, also allows adsorbed gas from deep within the fractures to be discharged, further improving the natural gas recovery rate. Titanate coupling agents are used to surface-treat the proppant, changing its weakly hydrophilic structure to a hydrophobic one, altering the wettability of the proppant surface, improving its suspension capacity in the fracturing fluid, slowing sedimentation, achieving a longer sand-carrying distance, reducing near-wellbore sedimentation, achieving a supporting effect on distal fractures, and further increasing production.

[0027] 3. The present invention discloses a micro-fracture mesh interface modified distal strong sand-carrying fracturing fluid and its preparation method. Alkyl polyoxyethylene ethers are used as modifying components, which can promote the dispersion of heavy components such as asphaltene and gum in crude oil to form an oil-water dispersion, thereby improving the fluid replacement efficiency and further enhancing the crude oil recovery rate.

[0028] 4. This invention relates to a micro-fracture network interface-modified distal-end strong proppant-carrying fracturing fluid and its preparation method. Zirconium lactate is synthesized through the reaction of zirconium oxychloride and sodium lactate in intermediate S. In zirconium lactate, zirconium ions are chelated and bound by lactate ions, resulting in a slower and more controllable release rate of zirconium ions. After the polymer in the fracturing fluid has swelled and stretched, the carboxyl hydroxyl reaction sites in the polymer structure combine with zirconium ions, forming a cross-linked network structure through coordination bonds. This enhances the proppant-carrying capacity of the system, thus avoiding the problems of excessively rapid zirconium ion release, poor polymer swelling, poor cross-linking effect, and poor proppant-carrying capacity. It also solves the problem of excessively slow zirconium ion release and inability of the polymer to cross-link.

[0029] 5. The present invention provides a micro-slit mesh interface-modified distal strong sand-carrying fracturing fluid and its preparation method. It uses ligands and delays the release rate of metal ions during use, so that the local polymer cross-linking reaction occurs 5-15 minutes after the fracturing fluid enters the ground, increasing the structural complexity and achieving the purpose of enhancing the sand-carrying capacity of the fracturing fluid at low flow rates in distal and branch fractures.

[0030] 6. The present invention provides a micro-slit mesh interface modified distal strong sand-carrying fracturing fluid and its preparation method. It uses low molecular weight polyacrylamide, which can achieve good breaking effect under the action of conventional breaking agents. It has good compatibility with commercially available breaking agents, and the liquid viscosity and residue are low after breaking.

[0031] 7. This invention relates to a micro-fracture network interface-modified distal-end strong proppant-carrying fracturing fluid and its preparation method. On the one hand, it timely enhances the proppant-carrying capacity of the fracturing fluid at low flow rates in distal and branch fractures. On the other hand, it uses an oil- and gas-conducting fracturing fluid system to infiltrate from the fracture and modify the interface of the micro-channels, reducing the strong adsorption of oil, gas and water by the micro-channels and ensuring the smooth flow of the micro-channels, thereby aiming to improve the oil and gas recovery rate. Detailed Implementation

[0032] The present invention will be further described below with reference to embodiments and test examples. The following embodiments and test examples are only a few specific implementations of the present invention, but the design concept of the present invention is not limited thereto. Any non-substantial modifications made to the present invention using this concept shall be considered as infringing upon the protection scope of the present invention.

[0033] Example

[0034] In one embodiment, a micro-fracture interface-modified distal-end strong sand-carrying fracturing fluid comprises, by weight, 20-50 parts low molecular weight polyacrylamide, 10-30 parts polyhydroxyethyl acrylamide, 30-75 parts diethylene glycol ethyl ether acetate, 2-10 parts fumed silica, 3-12 parts titanate coupling agent, 2-7 parts gemini cationic surfactant, 2-7 parts alkyl polyoxyethylene ether, and 2-7 parts intermediate S; wherein intermediate S, by weight, comprises 10-25 parts zirconium oxychloride, 5-25 parts sodium lactate, and 65-85 parts diethylene glycol ethyl ether acetate.

[0035] In one embodiment, the effective content of sodium lactate is >99%.

[0036] In one embodiment, the low molecular weight polyacrylamide has a molecular weight of 3-8 million, and the polyhydroxyethyl acrylamide has a molecular weight of 5-30 million.

[0037] In one embodiment, the titanate coupling agent is one or more of isopropyltris(dioctylpyrophosphate)titanate, isopropyl triisostearate titanate, and bis(triethanolamine) diisopropyltitanate, and the geminal cationic surfactant is one or more of bis(dodecyl)dimethylammonium chloride, bis(hexadecyl)dimethylammonium chloride, and bis(tetradecyl)dimethylammonium chloride.

[0038] In one embodiment, the alkyl polyoxyethylene ether is one or more of octadecylamine polyoxyethylene ether, dodecylamine polyoxyethylene ether, and hexadecylamine polyoxyethylene ether.

[0039] In one embodiment, a method for preparing a micro-fracture mesh interface-modified distal-end strong sand-carrying fracturing fluid includes the following steps:

[0040] Preparation of intermediate S1: The preparation of intermediate S includes the following steps:

[0041] A1: By weight, 5-25 parts of sodium lactate and 10-25 parts of zirconium oxychloride are mixed and added to 65-85 parts of diethylene glycol ethyl ether acetate. The mixture is heated to 50±5℃ under stirring and reacted for 2-3 hours to obtain intermediate A.

[0042] A2: Add pH adjuster to intermediate A several times, and take a 0.1% aqueous solution of intermediate A every 30 minutes to measure the pH value until the pH value is 4-5. Keep the material temperature constant at 50±5℃ and react for 4-5 hours. After cooling to room temperature, intermediate S is obtained. The weight ratio of pH adjuster to intermediate A added each time is 1:1000.

[0043] Preparation of finished product R (S2): The preparation of finished product R includes the following steps:

[0044] B1: Low molecular weight polyacrylamide, polyhydroxyethyl acrylamide, and fumed silica are added to diethylene glycol ethyl ether acetate in a certain proportion. The mixture is stirred evenly under high speed and allowed to stand for 1-1.5 hours to obtain intermediate B.

[0045] B2: Add titanate coupling agent and gemini cationic surfactant to intermediate B and stir at high speed until homogeneous. Let stand for 1-1.5 hours to obtain intermediate C.

[0046] B3: Add alkyl polyoxyethylene ethers to intermediate C and stir at high speed until homogeneous. Let stand for 1-2 hours to obtain intermediate D.

[0047] B4: Add intermediate S to intermediate D and mix evenly under high-speed stirring to obtain finished product R;

[0048] The amounts of the above reactants added, by weight, are: 20-50 parts low molecular weight polyacrylamide, 10-30 parts polyhydroxyethyl acrylamide, 30-75 parts diethylene glycol ethyl ether acetate, 2-10 parts fumed silica, 3-12 parts titanate coupling agent, 2-7 parts geminolytic surfactant, 2-7 parts alkyl polyoxyethylene ethers, and 2-7 parts intermediate S;

[0049] Preparation of S3 strong proppant-carrying fracturing fluid: The finished product R is prepared into a solution with a content of 0.1wt% to obtain the micro-fracture interface modified low-damage distal enhanced proppant-carrying fracturing fluid.

[0050] In one embodiment, the pH adjuster in step A2 is an ethanol solution of diethanolamine with a mass fraction of 10.0 wt%.

[0051] In one embodiment, the stirring speed in step A1 is 300-1000 r / min.

[0052] In one embodiment, in the preparation step of the S2 product R, the high-speed stirring speed is 1500-2500 r / min.

[0053] Test case

[0054] The experimental examples aim to obtain experimental and testing data of the technical solution of the present invention by conducting specific tests and evaluating indicators.

[0055] The test cases were conducted based on the implementation methods of the above embodiments, and specific operable test parameters were provided. Six test cases were set up, and the differences between the six test cases were in the compatibility of the components and raw materials. The test parameters and test group component formulations will be described in detail below.

[0056] Formulation: All 6 test cases included low molecular weight polyacrylamide, polyhydroxyethyl acrylamide, diethylene glycol ethyl ether acetate, fumed silica, titanate coupling agent, geminal cationic surfactant, alkyl polyoxyethylene ether, and intermediate S; intermediate S included zirconium oxychloride, sodium lactate, and diethylene glycol ethyl ether acetate.

[0057] Components: The strong sand-carrying fracturing fluid of this invention is a solution prepared from finished product R. The total weight of finished product R is set to 100g, and the actual amount of each component is added according to the calculation.

[0058] Test method:

[0059] Preparation of intermediate S1: The preparation of intermediate S includes the following steps:

[0060] A1: Sodium lactate and zirconium oxychloride were mixed and added to diethylene glycol ethyl ether acetate. The mixture was heated to 55°C under stirring and reacted for 2.5 h to obtain intermediate A; the effective content of sodium lactate was 99.5%.

[0061] A2: Add pH adjuster to intermediate A several times, and take a 0.1% aqueous solution of intermediate A every 30 minutes to measure the pH value until the pH value is 4.5. Keep the material temperature constant at 55℃ and react for 5 hours. After cooling to room temperature, intermediate S is obtained.

[0062] Preparation of finished product R (S2): The preparation of finished product R includes the following steps:

[0063] B1: Low molecular weight polyacrylamide, polyhydroxyethyl acrylamide, and fumed silica are added to diethylene glycol ethyl ether acetate in a certain proportion and mixed evenly under high-speed stirring. After standing for 1 hour, intermediate B is obtained; the molecular weight of low molecular weight polyacrylamide is 500 and the molecular weight of polyhydroxyethyl acrylamide is 15 million.

[0064] B2: Add titanate coupling agent and gemini cationic surfactant to intermediate B and stir at high speed until homogeneous. Let stand for 1.5 h to obtain intermediate C.

[0065] B3: Add alkyl polyoxyethylene ethers to intermediate C and stir at high speed until homogeneous. Let stand for 2 hours to obtain intermediate D.

[0066] B4: Add intermediate S to intermediate D and mix evenly under high-speed stirring to obtain finished product R;

[0067] Preparation of S3 strong proppant-carrying fracturing fluid: The finished product R is prepared into a solution with a content of 0.1wt% to obtain the micro-fracture interface modified low-damage distal enhanced proppant-carrying fracturing fluid.

[0068] More specifically, in step A2, the pH adjuster is an ethanol solution of diethanolamine with a mass fraction of 10.0 wt%.

[0069] More specifically, the stirring speed in step A1 is 800 r / min.

[0070] More specifically, in the preparation step of the S2 product R, the high-speed stirring speed is 2200 r / min.

[0071] This invention includes six specific experimental cases, and the formulation components of the experimental cases are shown below:

[0072] Experimental Example 1:

[0073] The intermediate S component includes zirconium oxychloride: 15 parts, sodium lactate: 20 parts, and diethylene glycol ethyl ether acetate: 70 parts.

[0074] The finished product R component includes 30 parts of polyacrylamide, 25 parts of polyhydroxyethyl acrylamide, 65 parts of diethylene glycol ethyl ether acetate, 5 parts of fumed silica, 5 parts of triisostearate titanate isopropyl triisostearate, 5 parts of bis(dodecyl)dimethylammonium chloride, 5 parts of dodecylamine polyoxyethylene ether, and 5 parts of intermediate S.

[0075] Experimental Example 2:

[0076] The intermediate S component includes zirconium oxychloride: 10 parts, sodium lactate: 20 parts, and diethylene glycol ethyl ether acetate: 70 parts;

[0077] The finished product R component includes 20 parts polyacrylamide, 30 parts polyhydroxyethyl acrylamide, 65 parts diethylene glycol ethyl ether acetate, 5 parts fumed silica, 5 parts isopropyl triisostearate titanate, 5 parts dodecyl dimethyl ammonium chloride, 5 parts dodecyl amino polyoxyethylene ether, and 5 parts intermediate S.

[0078] Experimental Example 3:

[0079] The intermediate S component includes zirconium oxychloride: 15 parts, sodium lactate: 25 parts, and diethylene glycol ethyl ether acetate: 70 parts.

[0080] The finished product R component includes 30 parts of polyacrylamide, 30 parts of polyhydroxyethyl acrylamide, 65 parts of diethylene glycol ethyl ether acetate, 2 parts of fumed silica, 3 parts of bis(triethanolamine) diisopropyl titanate, 2 parts of bis(dodecyl)dimethylammonium chloride, 5 parts of dodecylamine polyoxyethylene ether, and 5 parts of intermediate S.

[0081] Experimental Example 4:

[0082] The intermediate S component includes zirconium oxychloride: 15 parts, sodium lactate: 25 parts, and diethylene glycol ethyl ether acetate: 65 parts.

[0083] The finished product R component includes 30 parts of polyacrylamide, 30 parts of polyhydroxyethyl acrylamide, 65 parts of diethylene glycol ethyl ether acetate, 2 parts of fumed silica, 7 parts of triisostearate titanate isopropyl triisostearate, 7 parts of ditetradecyl dimethyl ammonium chloride, 5 parts of dodecylamine polyoxyethylene ether, and 5 parts of intermediate S.

[0084] Experimental Example 5:

[0085] The intermediate S component includes zirconium oxychloride: 15 parts, sodium lactate: 25 parts, and diethylene glycol ethyl ether acetate: 80 parts.

[0086] The finished product R component includes 30 parts of polyacrylamide, 30 parts of polyhydroxyethyl acrylamide, 75 parts of diethylene glycol ethyl ether acetate, 10 parts of fumed silica, 5 parts of triisostearate titanate isopropyl triisostearate, 5 parts of bis(dodecyl)dimethylammonium chloride, 5 parts of dodecylamine polyoxyethylene ether, and 5 parts of intermediate S.

[0087] Experimental Example 6:

[0088] The intermediate S component includes zirconium oxychloride: 25 parts, sodium lactate: 25 parts, and diethylene glycol ethyl ether acetate: 80 parts;

[0089] The finished product R component includes 30 parts of polyacrylamide, 10 parts of polyhydroxyethyl acrylamide, 50 parts of diethylene glycol ethyl ether acetate, 5 parts of fumed silica, 5 parts of triisostearate titanate isopropyl triisostearate, 5 parts of bis(dodecyl)dimethylammonium chloride, 5 parts of hexadecylamine polyoxyethylene ether, and 10 parts of intermediate S.

[0090] Conclusion: A series of index measurements were conducted on the above-mentioned Experiments 1-6, as shown in Table 1. Experiments 1-6 all met the index requirements and demonstrated good comprehensive performance. Experiment 1 is the optimal formulation, with the best 0.1wt% solution viscosity, sand-carrying capacity, residue content, and interfacial tension.

[0091] Table 1 Evaluation Data of Experimental Cases

[0092]

[0093]

[0094] The specific embodiments described above further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A microslit net interfacial modified far-end proppant-laden fracturing fluid, characterized in that, by weight, including 20-50 parts Low molecular weight polyacrylamide, 10-30 parts polyhydroxyethyl acrylamide, 30-75 parts diethylene glycol ethyl ether acetate, 2-10 parts fumed silica, 3-12 parts titanate coupling agent, 2-7 parts Gemini cationic surfactant, 2-7 parts alkyl polyoxyethylene ether, 2-7 parts intermediate S; the intermediate S by weight, including 10-25 parts zirconium oxychloride, 5-25 parts sodium lactate; 65-85 parts diethylene glycol ethyl ether acetate; The effective content of sodium lactate is > 99%; The molecular weight of the low molecular weight polyacrylamide is 3-8 million, and the molecular weight of the polyhydroxyethyl acrylamide is 5-30 million; The titanate coupling agent is one or more of isopropyl tri(dioctyl pyrophosphoric acyl oxygen) titanate, titanium isopropyl triisostearate, and bis-triethanolamine diisopropyl titanate, and the Gemini cationic surfactant is one or more of didodecyl dimethyl ammonium chloride, dicetyl dimethyl ammonium chloride, and ditetradecyl dimethyl ammonium chloride.

2. The microslit interfacial modified far-end proppant-laden fracturing fluid of claim 1, wherein, The alkyl polyoxyethylene ether is one or more of octadecyl amine polyoxyethylene ether, dodecyl amine polyoxyethylene ether, and hexadecyl amine polyoxyethylene ether.

3. The preparation method of the micro-slit net interface modified far-end strong sand-carrying fracturing fluid according to any one of claims 1-2, characterized in that, The preparation of the intermediate S includes the following steps: S1: The preparation of the intermediate S includes the following steps: A1: by weight, 5-25 parts of sodium lactate and 10-25 parts of zirconium oxychloride are mixed and added to 65-85 parts of diethylene glycol ethyl ether acetate, and stirred to 50±5℃, and reacted for 2-3h to obtain intermediate A; A2: PH adjuster is added to intermediate A several times, and the pH value of the 0.1% aqueous solution of intermediate A is measured every 30min, until the pH value is 4-5, the material temperature is constant at 50±5℃, and the reaction is carried out for 4-5h, and then cooled to room temperature to obtain intermediate S; the weight ratio of PH adjuster to intermediate A is 1:1000 each time; S2: The preparation of the finished product R includes the following steps: B1: According to a certain proportion, low molecular weight polyacrylamide, polyhydroxyethyl acrylamide, and fumed silica are added to diethylene glycol ethyl ether acetate, and stirred uniformly under high speed, and then placed for 1h-1.5h to obtain intermediate B; B2: Titanate coupling agent and Gemini cationic surfactant are added to intermediate B and stirred uniformly under high speed, and then placed for 1-1.5h to obtain intermediate C; B3: Alkyl polyoxyethylene ether is added to intermediate C and stirred uniformly under high speed, and then placed for 1-2h to obtain intermediate D; B4: Intermediate S is added to intermediate D and stirred uniformly under high speed to obtain the finished product R; The addition amount of the above reactants is: 20-50 parts of low molecular weight polyacrylamide, 10-30 parts of polyhydroxyethyl acrylamide, 30-75 parts of diethylene glycol ethyl ether acetate, 2-10 parts of fumed silica, 3-12 parts of titanate coupling agent, 2-7 parts of Gemini cationic surfactant, 2-7 parts of alkyl polyoxyethylene ether, and 2-7 parts of intermediate S. S3 preparation of strong sand-carrying fracturing fluid: the product R is configured into a solution with a content of 0.1wt% to obtain a microslit net interface modification low-damage far-end enhanced sand-carrying fracturing fluid.

4. The method for preparing a micro-slit mesh interface-modified distal-end strong proppant-carrying fracturing fluid according to claim 3, characterized in that, The pH regulator in the A2 step is a 10.0wt% diethanolamine ethanol solution.

5. The method for preparing a micro-slit mesh interface-modified distal-end strong proppant-carrying fracturing fluid according to claim 3, characterized in that, The stirring speed in the A1 step is 300-1000r / min.

6. The method for preparing a micro-slit mesh interface-modified distal-end strong proppant-carrying fracturing fluid according to claim 3, characterized in that, In the preparation step of the S2 product R, the high-speed stirring speed is 1500-2500r / min.

Images