An emulsion for fracturing fluid suitable for bio-glue flowback fluid and its preparation method.

Abstract

This invention belongs to the field of oil and gas well reservoir stimulation technology, specifically relating to an emulsion for fracturing fluid suitable for bio-colloid flowback fluids and its preparation method. The fracturing fluid emulsion for bio-colloid flowback fluids, by weight, comprises the following raw material components: 80-100 parts acrylamide, 20-30 parts glycyl alanine, 5-10 parts cyclomethylsiloxane oil-in-water dispersant, 10-20 parts 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 10-20 parts hydroxyethyl methacrylate, 15-30 parts 2-acrylamido-2-methylpropanesulfonic acid, 60-80 parts white oil, 5-10 parts emulsifier, 5-10 parts initiator, and 10-15 parts water. This fracturing fluid emulsion significantly increases the solids content while also improving the performance of the fracturing fluid product, thus exhibiting excellent thickening properties even when formulated with bio-colloid flowback fluids.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas well reservoir stimulation technology, specifically relating to an emulsion for fracturing fluid suitable for bio-gel flowback fluid and its preparation method. Background Technology

[0002] Currently, most fracturing fluids used in oil and gas well reservoir fracturing in China are online-mixed types, primarily emulsion-based. To reduce preparation time and improve operational efficiency, the emulsion concentration is increased to switch between different fluids during stages requiring the injection of linear gels and high-viscosity fluids.

[0003] Currently, conventional emulsion-type fracturing fluids have low effective content and cannot meet the requirements of on-site construction when mixed with flowback fluid. Therefore, emulsion-type fracturing fluids with increased effective content of acrylamide are receiving increasing attention. In addition, environmental protection requirements and the high cost of flowback fluid treatment have led to the current use of pure flowback fluid with high mineralization in the preparation of the fluid, which places higher demands on the salt resistance of the emulsion. Existing flowback fluid is mostly used to prepare fracturing fluids using suspension emulsion systems. When using it, the calcium and magnesium ions in the flowback fluid need to be treated first before the fracturing fluid base fluid is prepared, and then a crosslinking agent is added for use. However, this system has the following disadvantages: (1) It requires a treatment device to treat the flowback fluid to remove calcium and magnesium ions, generating new waste liquid and solid waste; (2) It requires a preparation vehicle and a large number of storage tanks; (3) A crosslinking agent needs to be added during the fracturing process, making the construction steps more complicated; (4) The preparation vehicle and storage tank occupy a large area and are not suitable for small well sites.

[0004] In view of this, the present invention is hereby proposed. Summary of the Invention

[0005] The purpose of this invention is to provide an emulsion for fracturing fluid suitable for bio-adhesive flowback fluid and its preparation method; this fracturing fluid emulsion significantly increases the effective content of acrylamide while also improving the performance of fracturing fluid products, thus exhibiting excellent thickening properties even when fracturing fluid is prepared with bio-adhesive flowback fluid.

[0006] To achieve the above objectives, the present invention provides the following technical solution:

[0007] An emulsion for fracturing fluid suitable for bio-adhesive flowback fluid, comprising the following raw material components by weight: 80-100 parts acrylamide, 20-30 parts glycyl alanine, 5-10 parts cyclomethylsiloxane oil-in-water dispersant, 10-20 parts 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 10-20 parts hydroxyethyl methacrylate, 15-30 parts 2-acrylamido-2-methylpropanesulfonic acid, 60-80 parts white oil, 5-10 parts emulsifier, 5-10 parts initiator, and 10-15 parts water.

[0008] Further, by weight, it includes the following raw material components: 95 parts acrylamide, 20 parts glycyl alanine, 10 parts cyclomethylsiloxane oil-in-water dispersant, 10 parts 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 15 parts hydroxyethyl methacrylate, 20 parts 2-acrylamide-2-methylpropanesulfonic acid, 65 parts white oil, 6 parts emulsifier, 5 parts initiator, and 10 parts water.

[0009] Furthermore, the emulsifier is a nonionic emulsifier with a hydrophilic-lipophilic balance value of 4 to 7.

[0010] Furthermore, the emulsifier is selected from at least one of Tween-20, OP-10, and polyether silicone oil.

[0011] Furthermore, the initiator is selected from one or more of sodium persulfate, potassium persulfate, and hydrogen peroxide, or a mixture thereof.

[0012] In addition, the present invention also provides a method for preparing the fracturing fluid emulsion as described above, which is prepared by reverse emulsion polymerization and includes the following steps:

[0013] S1. Add white oil and emulsifier to the reactor in proportion, and introduce nitrogen gas. Stir until completely dissolved to obtain a uniform oil phase medium for later use.

[0014] S2. Add deionized water to the reactor, and then dissolve acrylamide, glycyl alanine, cyclomethylsiloxane oil-in-water dispersant, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, hydroxyethyl methacrylate, and 2-acrylamide-2-methylpropanesulfonic acid in deionized water in sequence, stirring until completely dissolved to form an aqueous solution.

[0015] S3. Slowly add the aqueous solution formed in step S2 to the oil medium obtained in step S1. After the addition is complete, stir evenly to obtain an emulsion.

[0016] S4. Slowly add the initiator dropwise to the emulsion obtained in step S3. After the addition is complete, place the mixture in a constant temperature water bath for constant temperature reaction. After the reaction is complete, cool to room temperature and then disperse by ultrasonication to obtain the fracturing fluid emulsion.

[0017] Furthermore, in step S1, the stirring rate is 500 r / min.

[0018] Furthermore, in step S3, under the condition of maintaining a high-speed stirring speed of 1500 r / min, the aqueous phase solution formed in step S2 is slowly added dropwise to the oil phase medium obtained in step S1 using a constant pressure dropping funnel.

[0019] Furthermore, in step S3, after the addition is complete, the mixture is stirred continuously for 40 minutes, and nitrogen gas is continuously introduced during the stirring process.

[0020] Furthermore, in step S4, the isothermal reaction conditions are: isothermal reaction at 30°C for 3 hours; and / or, ultrasonic dispersion time is 30 minutes.

[0021] Compared with the prior art, the technical solution of the present invention has at least the following technical effects:

[0022] I. The fracturing fluid emulsion of the present invention is prepared by reverse emulsion polymerization. By introducing salt-resistant groups and steric hindrance groups into the macromolecular chain, the effective content of acrylamide is greatly increased, while the performance of the fracturing fluid product is also improved. Thus, it can also exhibit excellent thickening properties when fracturing fluid is prepared with bio-adhesive flowback fluid.

[0023] Second, the fracturing fluid emulsion prepared by this invention can be directly mixed online with the flowback fluid without the need to treat the flowback fluid to remove calcium and magnesium ions, and it does not require the fluid preparation vehicle to be prepared and stored in the storage tank in advance, which can save water treatment costs, on-site fluid preparation costs and storage tank transportation costs, etc. At the same time, it has good applicability to the reuse of flowback fluid. Detailed Implementation

[0024] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions in the embodiments of this invention will be clearly and completely described below in conjunction with the embodiments of this invention. Those skilled in the art should understand that the embodiments described are merely illustrative of the invention and should not be considered as specific limitations thereof. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention. Process parameters not specifically specified in the following embodiments are generally performed under conventional conditions.

[0025] The endpoints and any values ​​of the ranges disclosed in this invention 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 endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0026] According to a first aspect of the present invention, a fracturing fluid emulsion suitable for bio-glue flowback fluid is provided, comprising, by weight, the following raw material components: 80-100 parts of acrylamide (e.g., 80, 82, 84, 86, 88, 90, 92, 94, 96, 98, 100 parts), and 20-30 parts of glycyl alanine (e.g., 20, 21, 22, 23, 24, 25 parts). 5-10 parts (e.g., 5, 6, 7, 8, 9, 10 parts) of cyclomethylsiloxane oil-in-water dispersant, 10-20 parts (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, and 10 parts of hydroxyethyl methacrylate. ~20 parts (e.g., 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20 parts)), 15-30 parts of 2-acrylamide-2-methylpropanesulfonic acid (e.g., 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30 parts), 60- 80 parts (e.g., 60, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80 parts), 5-10 parts emulsifier (e.g., 5, 6, 7, 8, 9, 10 parts), 5-10 parts initiator (e.g., 5, 6, 7, 8, 9, 10 parts), 10-15 parts water (e.g., 10, 11, 12, 13, 14, 15 parts).

[0027] The raw materials used in the fracturing fluid emulsion of this invention are all commercially available products. By introducing 2-acrylamide-2-methylpropanesulfonic acid into the macromolecular chain, the temperature and salt resistance of the molecule is significantly improved. The introduction of the sterically hindered dimethyl carbonate group reduces the coiling effect of the macromolecular chain under high salinity conditions, which is more conducive to the construction of a long-chain macromolecular structure. On the one hand, while significantly increasing the effective solid content (through molecular structure design, the introduction of functional groups with acrylamide groups increases the number of acrylamide groups in the molecular chain), the stability is improved. Moreover, it can also improve the performance of fracturing fluid products, thus exhibiting excellent thickening performance even when fracturing fluid is prepared with bio-adhesive flowback fluid. On the other hand, since the long-chain macromolecule can maintain better viscoelasticity in high salinity water, it has stable proppant carrying capacity. When directly mixed online with flowback fluid, there is no need to treat the flowback fluid to remove calcium and magnesium ions, and there is no need to prepare and store it in the storage tank in advance. This can save water treatment costs, on-site preparation costs, and storage tank transportation costs, etc. At the same time, it has good applicability to the reuse of flowback fluid.

[0028] The weight portions described in this invention mainly include the disclosed numerical range, any value (including integers and decimals) within the disclosed range, or an interval between any two values, or multiple discontinuous intervals. It also includes values ​​or numerical ranges whose effects are expected to be similar to the endpoints of the numerical range, such as 5-10 parts. This does not only include 5, 6, 7, 8, 9, 10 parts, or any interval between any two parts. Other numerical ranges, not listed individually, are all included in this invention. Therefore, this invention also includes sub-ranges of any directly disclosed numerical range or any specific value within that range.

[0029] To further adapt the emulsion for fracturing fluids to bio-adhesive flowback fluids, this invention investigated the influence of different proportions of various components on their effectiveness, and obtained a more optimal component ratio as follows: by weight, the raw material components include: 95 parts acrylamide, 20 parts glycyl alanine, 10 parts cyclomethylsiloxane oil-in-water dispersant, 10 parts 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 15 parts hydroxyethyl methacrylate, 20 parts 2-acrylamide-2-methylpropanesulfonic acid, 65 parts white oil, 6 parts emulsifier, 5 parts initiator, and 10 parts water.

[0030] In the above-mentioned fracturing fluid emulsion, as a preferred embodiment, the emulsifier is a nonionic emulsifier with a hydrophilic-lipophilic balance value of 4 to 7. More preferably, the emulsifier is selected from at least one of Tween-20, OP-10, and polyether silicone oil.

[0031] In the above-mentioned fracturing fluid emulsion, as a preferred embodiment, the initiator is selected from one or more of sodium persulfate, potassium persulfate and hydrogen peroxide, or a mixture thereof.

[0032] According to a second aspect of the present invention, a method for preparing the fracturing fluid emulsion as described above is provided, which is prepared by reverse emulsion polymerization and includes the following steps:

[0033] S1. Add white oil and emulsifier to the reactor in proportion, and purge with nitrogen to remove oxygen. Stir until completely dissolved to obtain a uniform oil phase medium for later use.

[0034] S2. Add deionized water to the reactor, and then dissolve acrylamide, glycyl alanine, cyclomethylsiloxane oil-in-water dispersant, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, hydroxyethyl methacrylate, and 2-acrylamide-2-methylpropanesulfonic acid in deionized water in sequence, stirring until completely dissolved to form an aqueous solution.

[0035] S3. Slowly add the aqueous solution formed in step S2 to the oil medium obtained in step S1. After the addition is complete, stir evenly to obtain an emulsion.

[0036] S4. Slowly add the initiator dropwise to the emulsion obtained in step S3. After the addition is complete, place the mixture in a constant temperature water bath for constant temperature reaction. After the reaction is complete, cool to room temperature and then disperse by ultrasonication to obtain the fracturing fluid emulsion.

[0037] In the above preparation method, as a preferred embodiment, the stirring rate in step S1 is 500 r / min.

[0038] In the above preparation method, as a preferred embodiment, in step S3, under the condition of maintaining a high-speed stirring of 1500 r / min, the aqueous phase solution formed in step S2 is slowly added dropwise to the oil phase medium obtained in step S1 using a constant pressure dropping funnel.

[0039] In the above preparation method, as a preferred embodiment, in step S3, after the addition is completed, the mixture is stirred continuously for 40 minutes, and nitrogen is continuously introduced to remove oxygen during the stirring process.

[0040] In the above preparation method, as a preferred embodiment, in step S4, the isothermal reaction conditions are: isothermal reaction at 30°C for 3 hours; and / or, ultrasonic dispersion time is 30 minutes.

[0041] The present invention will now be described in detail with reference to embodiments thereof. These examples are provided by way of explanation and not by way of limitation. In fact, those skilled in the art will recognize that modifications and variations can be made to the present invention without departing from its scope or spirit. For example, a feature shown or described as part of one embodiment may be used in another embodiment to produce yet another embodiment. Therefore, it is desirable that the present invention encompass such modifications and variations falling within the scope of the appended claims and their equivalents.

[0042] In the embodiments of the present invention, unless otherwise specified, the experimental methods used are conventional methods, and the materials and reagents used are commercially available unless otherwise specified.

[0043] The main raw materials used in this embodiment are described below:

[0044] Acrylamide: Industrial grade 99% Hebei Sanfu Environmental Protection Technology Co., Ltd.

[0045] Glycylalanine: Industrial grade 99% Hebei Sanfu Environmental Protection Technology Co., Ltd.

[0046] Cyclomethylsiloxane water-in-oil dispersant: DC5225 water-in-oil emulsifier, Hebei Sanfu Environmental Protection Technology Co., Ltd.

[0047] 1-(3-Dimethylaminopropyl)-3-ethylcarbodiimide: 99% high quality Tianjin Pude Industry & Trade Co., Ltd.

[0048] Hydroxyethyl methacrylate: 98% purity premium grade, Tianjin Pude Industry & Trade Co., Ltd.

[0049] 2-Acrylamide-2-methylpropanesulfonic acid: 99% pure premium grade, Tianjin Pude Industry & Trade Co., Ltd.

[0050] White oil: Industrial grade No. 5, high quality, Tianjin Pude Industry & Trade Co., Ltd.

[0051] Example 1

[0052] (1) Add 65g of white oil and 6g of emulsifier to a 1000mL reactor in proportion, and introduce nitrogen gas. Stir at 500r / min until completely dissolved to obtain a uniform oil phase for later use.

[0053] (2) Add 15g of deionized water to a 500mL beaker. Then, dissolve 85g of acrylamide, 20g of glycyl alanine, 10g of cyclomethylsiloxane oil-in-water dispersant, 10g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 15g of hydroxyethyl methacrylate, and 20g of 2-acrylamide-2-methylpropanesulfonic acid in the deionized water and stir until completely dissolved to form an aqueous solution. While maintaining a high-speed stirring rate of 1500r / min, slowly add the aqueous solution to the oil phase medium using a constant-pressure dropping funnel. After the addition is complete, continue stirring for 40min until a homogeneous and stable emulsion is formed, continuously purging with nitrogen gas during the stirring process. Finally, set the reactor temperature to 30℃ and slowly add 5g of initiator at this temperature while maintaining a certain stirring rate to initiate the reaction.

[0054] (3) After the initiator is added, stop stirring the mixture and place it in a constant temperature water bath. After reacting at 30°C for 3 hours, cool the emulsion to room temperature and disperse it under ultrasonic conditions to obtain the fracturing fluid emulsion of this embodiment.

[0055] Example 2

[0056] (1) Add 70g of white oil and 6g of emulsifier to a 1000mL reactor in proportion, and introduce nitrogen gas. Stir at 500r / min until completely dissolved to obtain a uniform oil phase for later use.

[0057] (2) Add 15g of deionized water to a 500mL beaker. Then, dissolve 90g of acrylamide, 20g of glycyl alanine, 5g of cyclomethylsiloxane oil-in-water dispersant, 10g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 15g of hydroxyethyl methacrylate, and 20g of 2-acrylamide-2-methylpropanesulfonic acid in the deionized water and stir until completely dissolved to form an aqueous solution. While maintaining a high-speed stirring rate of 1500r / min, slowly add the aqueous solution to the oil phase medium using a constant-pressure dropping funnel. After the addition is complete, continue stirring for 40min until a homogeneous and stable emulsion is formed, and continuously purge with nitrogen gas during the stirring process. Finally, set the reactor temperature to 30℃ and slowly add 5g of initiator at this temperature while maintaining a certain stirring rate to initiate the reaction.

[0058] (3) After the initiator is added, stop stirring the mixture and place it in a constant temperature water bath. After reacting at 30°C for 3 hours, cool the emulsion to room temperature and disperse it under ultrasonic conditions to obtain the fracturing fluid emulsion of this embodiment.

[0059] Example 3

[0060] (1) Add 75g of white oil and 6g of emulsifier to a 1000mL reactor in proportion, and introduce nitrogen gas. Stir at 500r / min until completely dissolved to obtain a uniform oil phase for later use.

[0061] (2) Add 15g of deionized water to a 500mL beaker. Then, dissolve 90g of acrylamide, 20g of glycyl alanine, 10g of cyclomethylsiloxane oil-in-water dispersant, 10g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 15g of hydroxyethyl methacrylate, and 20g of 2-acrylamide-2-methylpropanesulfonic acid in the deionized water and stir until completely dissolved to form an aqueous solution. While maintaining a high-speed stirring rate of 1500r / min, slowly add the aqueous solution to the oil phase medium using a constant-pressure dropping funnel. After the addition is complete, continue stirring for 40min until a homogeneous and stable emulsion is formed, continuously purging with nitrogen gas during the stirring process. Finally, set the reactor temperature to 30℃ and slowly add 5g of initiator at this temperature while maintaining a certain stirring rate to initiate the reaction.

[0062] (3) After the initiator is added, stop stirring the mixture and place it in a constant temperature water bath. After reacting at 30°C for 3 hours, cool the emulsion to room temperature and disperse it under ultrasonic conditions to obtain the fracturing fluid emulsion of this embodiment.

[0063] Example 4

[0064] (1) Add 65g of white oil and 6g of emulsifier to a 1000mL reactor in proportion, and introduce nitrogen gas. Stir at 500r / min until completely dissolved to obtain a uniform oil phase for later use.

[0065] (2) Add 15g of deionized water to a 500mL beaker. Then, dissolve 95g of acrylamide, 20g of glycyl alanine, 10g of cyclomethylsiloxane oil-in-water dispersant, 10g of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 15g of hydroxyethyl methacrylate, and 20g of 2-acrylamide-2-methylpropanesulfonic acid in the deionized water and stir until completely dissolved to form an aqueous solution. While maintaining a high-speed stirring rate of 1500r / min, slowly add the aqueous solution to the oil phase medium using a constant-pressure dropping funnel. After the addition is complete, continue stirring for 40min until a homogeneous and stable emulsion is formed, and continuously purge with nitrogen gas during the stirring process. Finally, set the reactor temperature to 30℃ and slowly add 5g of initiator at this temperature while maintaining a certain stirring rate to initiate the reaction.

[0066] (3) After the initiator is added, stop stirring the mixture and place it in a constant temperature water bath. After reacting at 30°C for 3 hours, cool the emulsion to room temperature and disperse it under ultrasonic conditions to obtain the fracturing fluid emulsion of this embodiment.

[0067] Effect Comparison

[0068] Performance comparison of this product with conventional products: The fracturing fluid emulsions of Examples 1-4 are compared with conventional emulsions (N,N-dimethylamide, low molecular weight thickener emulsion for fracturing, manufacturer: Dongfang Baolin Technology Development (Beijing) Co., Ltd.). The fracturing fluids are prepared with water and bio-glue flowback fluid with a mineralization of 30,000 ppm, respectively.

[0069] The performance of fracturing fluid products was compared in terms of effective component content, water-based fracturing fluid formulation (fracturing fluid formula: water + 1.0% emulsion), and bio-collagen flowback fluid (mineralization greater than 30,000 ppm) formulation (fracturing fluid formula: bio-collagen flowback fluid + 1.0% emulsion). The test results are shown in Tables 1, 2, and 3 below.

[0070] Table 1

[0071] Emulsion type Regular emulsion type Example 1 Example 2 Example 3 Example 4 Acrylamide effective content, % 25-26 45 47 49 52

[0072] Table 2 Performance of fracturing fluids prepared with water

[0073]

[0074] Table 3 Performance of fracturing fluids formulated with bio-adhesive flowback fluid

[0075]

[0076]

[0077] Comparative analysis reveals that conventional emulsion products have low effective solids content, resulting in mediocre viscosity in fracturing fluids prepared with water. Furthermore, the viscosity of fracturing fluids prepared with high-mineralization flowback fluids decreases significantly, failing to meet on-site operational requirements. The product in this example, while substantially increasing solids content, utilizes reverse emulsion polymerization to prepare a salt-resistant emulsion. This introduces salt-resistant and sterically hindered groups into the macromolecular chains, enhancing the product's performance and effectively leveraging the advantages of high solids content. Consequently, it exhibits excellent thickening properties even when mixed with bio-adhesive flowback fluids in fracturing fluid preparations.

[0078] The foregoing has described and evaluated some embodiments of the present invention. It should be understood that the present invention is not limited to the specific embodiments described above. Any person skilled in the art can make many possible variations and modifications to the technical solutions of the present invention, or modify them into equivalent embodiments, without departing from the scope of the present invention. This does not affect the essential content of the present invention. Therefore, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of the present invention, without departing from the content of the present invention, still fall within the protection scope of the present invention.

Claims

1. An emulsion for fracturing fluids suitable for use in biogel flowback fluids, characterized in that, By weight, it comprises the following raw material components: 80-100 parts acrylamide, 20-30 parts glycyl alanine, 5-10 parts cyclomethylsiloxane oil-in-water dispersant, 10-20 parts 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 10-20 parts hydroxyethyl methacrylate, 15-30 parts 2-acrylamido-2-methylpropanesulfonic acid, 60-80 parts white oil, 5-10 parts emulsifier, 5-10 parts initiator, and 10-15 parts water.

2. The emulsion for a fracturing fluid according to claim 1, characterized by By weight, it comprises the following raw material components: 95 parts acrylamide, 20 parts glycyl alanine, 10 parts cyclomethylsiloxane oil-in-water dispersant, 10 parts 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, 15 parts hydroxyethyl methacrylate, 20 parts 2-acrylamide-2-methylpropanesulfonic acid, 65 parts white oil, 6 parts emulsifier, 5 parts initiator, and 10 parts water.

3. The emulsion for a fracturing fluid according to claim 1 or 2, characterized by, The emulsifier is a nonionic emulsifier with a hydrophilic-lipophilic balance value of 4 to 7.

4. The emulsion for a fracturing fluid according to claim 3, characterized by The emulsifier is selected from at least one of Tween-20, OP-10 and polyether silicone oil.

5. The emulsion for a fracturing fluid according to claim 1 or 2, characterized by, The initiator is selected from one or more of sodium persulfate, potassium persulfate, and hydrogen peroxide, or a mixture thereof.

6. A method of preparing an emulsion for a fracturing fluid as claimed in any one of claims 1 to 5, characterised in that, Prepared by reverse emulsion polymerization, including the following steps: S1. Add white oil and emulsifier to the reactor in proportion, and introduce nitrogen gas. Stir until completely dissolved to obtain a uniform oil phase medium for later use. S2. Add deionized water to the reactor, and then dissolve acrylamide, glycyl alanine, cyclomethylsiloxane oil-in-water dispersant, 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide, hydroxyethyl methacrylate, and 2-acrylamide-2-methylpropanesulfonic acid in deionized water in sequence, stirring until completely dissolved to form an aqueous solution. S3. Slowly add the aqueous solution formed in step S2 to the oil medium obtained in step S1. After the addition is complete, stir evenly to obtain an emulsion. S4. Slowly add the initiator dropwise to the emulsion obtained in step S3. After the addition is complete, place the mixture in a constant temperature water bath for constant temperature reaction. After the reaction is complete, cool to room temperature and then disperse by ultrasonication to obtain the fracturing fluid emulsion.

7. The production method according to claim 6, wherein In step S1, the stirring rate is 500 r / min.

8. The preparation method according to claim 6, characterized in that, In step S3, under the condition of maintaining a high-speed stirring speed of 1500 r / min, the aqueous phase solution formed in step S2 is slowly added dropwise to the oil phase medium obtained in step S1 using a constant pressure dropping funnel.

9. The preparation method according to claim 6, characterized in that, In step S3, after the addition is complete, stir continuously for 40 minutes, and continuously introduce nitrogen gas during the stirring process.

10. The method of claim 6, wherein, In step S4, the isothermal reaction conditions are: isothermal reaction at 30°C for 3 hours; and / or, ultrasonic dispersion time is 30 minutes.

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