Proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid apparatus and method

Abstract

This invention discloses a device and method for continuous mixing of polymer dry powder for proppant-assisted dispersion fracturing fluid, comprising a power mechanism, a dispersion and mixing mechanism, a feeding mechanism, and a stirring mechanism. The dispersion and mixing mechanism includes a shell and a screw-type stirring feeder and two rows of stirring paddles disposed inside the shell. The upper part of the shell is provided with a solid particle injection port, a dispersant injection port, and a polymer dry powder injection port. An outlet is provided at the lower part of the shell near the feeding mechanism. The feeding mechanism is a screw feeder with one inlet and multiple outlets. The lower outlet of the dispersion and mixing mechanism is located above the inlet of the feeding mechanism; the outlet is located above the stirring mechanism. The device of this invention is simple, low-cost, low-energy-consumption, and highly applicable to mining sites. The fracturing fluid prepared by the solid particle dispersion and solubilization method has advantages such as sufficient viscosity building, no fisheyes, and low reservoir damage.

Description

Technical Field

[0001] This invention belongs to the field of reservoir stimulation technology, specifically relating to a device and method for continuous mixing of proppant-assisted polymer dry powder fracturing fluid. Background Technology

[0002] Unconventional reservoirs include tight oil, shale oil, tight gas, coalbed methane, and shale gas. These reservoirs are often distributed over large areas in a continuous manner, without obvious traps, and have poor porosity and permeability conditions. They require large-scale modification before they can achieve economic production capacity.

[0003] For unconventional reservoirs, volumetric fracturing is one of the most important stimulation technologies. This technology enables large-scale fracturing stimulation of unconventional reservoirs, improves reservoir oil and gas flow, and connects deep reservoirs to oil and gas wellbores, ultimately achieving economical and efficient development of unconventional reservoirs. Thickeners are used during fracturing. Their main function is to reduce the resistance of the fracturing fluid by increasing its viscosity, improve its proppant-carrying capacity, reduce fluid loss within the fracture, and enhance fracture conductivity. Currently, over 90% of volumetric fracturing uses emulsion-type polymer thickeners. These thickeners contain only 40%–45% effective polymers and suffer from complex compositions, a tendency to agglomerate, easy stratification and precipitation, and the potential for damage to the reservoir from the oil phase solvent (50%) and solid phase suspending agent (2%). However, there is significant potential for cost reduction. Therefore, the advantages of polymer dry powder direct-mix fracturing fluid technology, such as simple reagents, controllable cost, convenient transportation, and low reservoir damage, have demonstrated its important vitality in the field. However, the current polymer dry powder direct-mix fracturing fluid technology first uses special equipment to prepare the fracturing fluid thickener mother liquor, and then dilutes it a second time in a mixing tank. This special equipment is large in size, expensive, and energy-intensive. In addition, the thickener mother liquor has high viscosity and is prone to clogging the equipment, leading to frequent accidents in the field.

[0004] To overcome the above problems, a series of technical solutions for directly preparing fracturing fluid from dry powder have emerged. Chinese patent CN222900878U discloses a continuous online mixing device for preparing fracturing fluid from dry powder, designing a device for directly preparing fracturing fluid from dry powder, with multi-stage stirring as its core concept. This device's technical approach is relatively traditional; relying solely on stirring results in problems such as incomplete water-powder dispersion and severe fisheyes when preparing high-viscosity fracturing fluids. This device lacks substantial innovation.

[0005] Chinese patent CN119499904A discloses an apparatus and method for preparing fracturing fluid from polymer dry powder. This patent relies on the Venturi effect to achieve primary mixing of the dry powder and uses a shear emulsification pump to further mix the powder and high-pressure water. A high-pressure water pipe and a premixing pipe are used to form an annular powder channel. This annular channel can evenly distribute the dry powder around the circumference of the high-pressure water pipe. The Venturi effect generated by the high-pressure water passing through the end of the high-pressure water pipe continuously draws the dry powder in circumferentially, increasing the contact between the dry powder and water and reducing the risk of agglomeration to some extent. After the powder and high-pressure water are mixed, a stirring turbine is used for further mixing. The fully mixed powder and high-pressure water then enter the shear emulsification pump for further processing. This apparatus, involving a Venturi high-pressure pipe, stirring turbine, and shear emulsification pump, all require a large amount of energy. Furthermore, the stirring turbine is prone to fish-eye buildup, leading to blockages and equipment failure.

[0006] Chinese patent CN118788202A discloses a dry powder viscous fracturing fluid mixing device. The invention employs a two-stage mixing method for fracturing fluid mixing. The first stage is a fluidized bed premixing, primarily to eliminate lumps and perform preliminary mixing to prevent lumps from clogging subsequent pipelines. The second stage is high-shear mixing in an emulsifier pump. The fluidized bed uses particulate material as the dispersion medium and inert gas as the backflushing fluid. A separator is used to separate the fracturing fluid from the particulate material, ensuring full utilization. However, this invention has a relatively complex overall structure, occupies a large space, and consumes a lot of energy. It requires the use of gas as the dispersion fluid and particles as the dispersion medium, resulting in excessive material consumption and processing difficulties, making it impractical for mining operations.

[0007] Therefore, providing a polymer dry powder direct-mix fracturing fluid equipment and dispersion method that is technically stable and reliable, low in energy consumption, simple in equipment, and low in cost is of great practical significance for reducing costs and increasing efficiency in large-scale volume fracturing of unconventional reservoirs, and is also a technical problem that urgently needs to be solved in this field. Summary of the Invention

[0008] This invention is proposed to solve the problems of uneven water-powder dispersion, easy clogging, complex equipment, large station space, and high energy consumption in the current volumetric fracturing of polymer dry powder direct mixing fracturing fluid. Its purpose is to provide a device and method for continuous mixing fracturing fluid of polymer dry powder with proppant-assisted dispersion.

[0009] This invention is achieved through the following technical solution: A proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device includes a power mechanism, a dispersion and mixing mechanism, a feeding mechanism, and a stirring mechanism. The dispersion and mixing mechanism includes a shell and a screw-type stirring feeder and two rows of stirring paddles disposed inside the shell. The upper part of the shell is provided with a solid particle injection port, a dispersant injection port, and a polymer dry powder injection port. An outlet is provided at the lower part of the shell near the feeding mechanism. The feeding mechanism is a screw feeder with one inlet and multiple outlets. The lower outlet of the dispersion and mixing mechanism is located above the inlet of the feeding mechanism. The outlet is located above the stirring mechanism.

[0010] In the above technical solution, the two rows of stirring paddles are symmetrically arranged with the axis of the screw-type stirring feeder as the center line, and the axes of the screw-type stirring feeder and the two rows of stirring paddles are arranged parallel to each other.

[0011] In the above technical solution, the stirring paddle is a double-cross oblique blade stirring paddle, which includes a drive shaft and multiple sets of stirring blades arranged on the drive shaft; each set of stirring blades includes two stirring blades, and the planes on which the two stirring blades are located make angles of 45° and 135° with the axis of the drive shaft, respectively.

[0012] In the above technical solution, the output shaft of the power mechanism is connected to the rotating shaft and transmission shaft of the screw-type mixing feeder.

[0013] In the above technical solution, the mixing mechanism is the mixing tank of a fracturing sand mixing truck.

[0014] In the above technical solution, the stirring mechanism includes a tank and a stirrer disposed in the tank. The upper part of the tank is provided with a liquid inlet and the lower part of the tank is provided with a discharge outlet.

[0015] A method for continuously mixing fracturing fluid with proppant-assisted dispersion of polymer dry powder using the aforementioned apparatus includes the following steps: S1. Determine the fracturing stage and determine the mass concentrations of polymer dry powder, dispersant and solid particles in the fracturing fluid based on the fracturing stage. S2. According to the proportion determined in step S1, the polymer dry powder, dispersant and solid particles are added to the dispersion and mixing mechanism of the proppant-assisted continuous mixing fracturing fluid device through the corresponding feed inlet. S3. The fracturing fluid is prepared by a continuous mixing device for polymer dry powder dispersed with proppant, and the prepared fracturing fluid is obtained from the outlet of the stirring mechanism.

[0016] In the above technical solution, the fracturing stage includes the pre-flush stage, the low sand ratio stage, the main sand addition stage, and the displacement fluid stage.

[0017] In the above technical solution, the polymer dry powder has a mesh size of 60-100 mesh and a molecular weight of 16 million-22 million, and 2 wt% urea is added to the polymer dry powder; the dispersant is an alcoholic solution of a drainage aid or an alcoholic solution of a clay stabilizer; the solid particles are proppant or salt particles; the proppant is 16-100 mesh ceramsite or quartz sand; the salt is KCl; the solid particles added in the pre-liquid stage and the displacement liquid stage are salt particles, and the solid particles added in the low sand ratio stage and the main sand addition stage are proppant.

[0018] In the above technical solution, the mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid during the pre-flush stage are 0.04%, 0.3%, and 2%, respectively; the mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid during the low sand ratio stage are 0.15%, 0.3%, and 5%~15%, respectively; the mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid during the main sand addition stage are 0.30%, 0.3%, and 15%~30%, respectively; and the mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid during the displacement fluid stage are 0.04%, 0.3%, and 2%, respectively.

[0019] The beneficial effects of this invention are: This invention provides a proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device and method. It utilizes the characteristic that the viscosity of fracturing fluid is directly proportional to the proppant concentration during fracturing. By using proppant as a dispersion medium and dispersant to assist in the dispersion and spreading of polymer dry powder in the continuous mixing fracturing fluid, the invention promotes the full dispersion, dissolution, and adhesion of polymer dry powder in the fracturing fluid. Ultimately, with simple operating equipment and low energy consumption, stable fracturing fluid can be directly prepared from polymer dry powder.

[0020] The device of this invention uses a combination of a screw-type stirring feeder and a double-crossing oblique blade stirring paddle to achieve thorough and uniform mixing and transfer of various materials. During fracturing operations, various solid / liquid phase materials required for fracturing fluid are added sequentially, thoroughly stirred, uniformly mixed, and sprinkled into a mixing tank to achieve continuous mixing of fracturing fluid. The device of this invention features simple equipment, low cost, and low energy consumption. The fracturing fluid prepared has advantages such as sufficient viscosity, no fisheyes, low reservoir damage, and low cost, realizing the successful implementation of direct mixing of polymer dry powder fracturing fluid in the field. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of the proppant-assisted dispersion polymer dry powder thickening and solubilizing device of the present invention; Figure 2 This is a top view of the dispersing mixer in the solubilizing device of the present invention; Figure 3This is a side view of the dispersing mixer in the solubilizing device of the present invention.

[0022] in: 1. Power mechanism; 2. Dispersion and mixing mechanism; 201. Shell; 202. Screw-type agitator feeder; 203. Solid particle inlet; 204. Dispersant inlet; 205. Polymer dry powder inlet; 206. Drive shaft; 207. Agitator blades; 3. Distributor; 301. Discharge port; 4. Mixing tank; 401. Tank body; 402. Agitator; 403. Discharge port; 404. Liquid inlet.

[0023] For those skilled in the art, other related figures can be obtained from the above figures without any creative effort. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solution of the present invention, the technical solution of the present invention will be further described below with reference to the accompanying drawings and specific embodiments.

[0025] Example 1 like Figures 1-3 As shown, a proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device includes a power mechanism 1, a dispersion and mixing mechanism 2, a material distribution mechanism 3, and a stirring mechanism 4. The dispersion mixing mechanism 2 includes a housing 201 and a screw-type stirring feeder 202 and two rows of stirring paddles disposed inside the housing 201; the two rows of stirring paddles are symmetrically arranged with the axis of the screw-type stirring feeder 204 as the center line, and the axes of the screw-type stirring feeder 202 and the two rows of stirring paddles are parallel. The upper part of the shell 201 is provided with a solid particle injection port 203, a dispersant injection port 204 and a polymer dry powder injection port 205 respectively; an outlet is provided at the lower part of the shell 201 near the material distribution mechanism 3; The screw-type mixing feeder 202 is a conventional commercially available device. The impeller is a double-cross oblique blade impeller, which includes a drive shaft 206 and multiple sets of impeller blades mounted on the drive shaft 206; each impeller blade set includes two impeller blades 207, and the planes of the two impeller blades 207 are at angles of 45° and 135° with the axis of the drive shaft 206, respectively. During operation, the screw-type mixing feeder 202 can mix materials and extrude materials to the outlet end of the dispersing mixer; the double-cross inclined blade agitator rotates counterclockwise and clockwise respectively, so that the proppant and other materials are fully lifted to the screw-type mixing feeder, and the cross-symmetrical inclined blade structure ensures that the proppant can be fully mixed, and the proppant can only move in the axial direction perpendicular to the screw-type mixing feeder; The output shaft of the power mechanism 1 is connected to the rotating shaft and transmission shaft 206 of the screw-type mixing feeder 204, thereby driving the screw-type mixing feeder 204 and the two rows of mixing blades. The power mechanism 1 can use three independently set motors, which are respectively connected to the screw-type mixing feeder 204 and the two rows of mixing blades to achieve driving, or use one motor, which is connected to the screw-type mixing feeder 204 and the two rows of mixing blades through a connector; The material distribution mechanism 3 is a screw feeder with one inlet and multiple outlets 301; the lower outlet of the dispersion and mixing mechanism 2 is located above the inlet of the material distribution mechanism 3; the outlets 301 are located above the stirring mechanism 4; the material distribution system evenly distributes the mixture into the mixing tank, so that the polymer is completely dissolved and uniformly viscous. The mixing mechanism 4 is a mixing tank of a fracturing sand mixing truck; The stirring mechanism 4 includes a tank 401 and a stirrer 402 disposed inside the tank 401. The upper part of the tank 401 is provided with a liquid inlet 404, and the lower part of the tank 401 is provided with a discharge outlet 403.

[0026] Example 2 A method for continuously mixing fracturing fluid with polymer dry powder using the proppant-assisted dispersion apparatus of Example 1 includes the following steps: S1. Determine the fracturing stage and determine the mass concentrations of polymer dry powder, dispersant and solid particles in the fracturing fluid based on the fracturing stage. The fracturing stage includes the pre-flush stage, the low sand ratio stage, the main sand addition stage, and the displacement fluid stage. The polymer powder has a mesh size of 60-100 mesh and a molecular weight of 16-22 million. 2 wt% urea is added to the polymer powder to improve its rapid solubility. Since the polymer powder does not stick in the alcohol solution, and the alcohol solution dispersed on the proppant surface can coat the polymer powder, it facilitates thorough mixing between the polymer powder and the proppant. The mass concentration of the polymer powder in the fracturing fluid is 0.04%-0.30%. The bulk density of commonly used polymer powder is 0.6 g / cm³. 3 ; The dispersant is an alcoholic solution of a proppant or an alcoholic solution of a clay stabilizer; the alcoholic solution can be well dispersed and spread on the proppant surface under the stirring action of the dispersant mixer; the mass concentration of the dispersant in the fracturing fluid is consistently 0.3%; The discharge aid can be anionic surfactant, nonionic surfactant, fluorocarbon discharge aid, alcohol discharge aid, or nanofluid discharge aid; The clay stabilizer may be an inorganic salt clay stabilizer or a quaternary ammonium salt clay stabilizer. The solid particles are proppant or salt particles; The proppant is a variety of proppants with a mesh size of 16-100, such as ceramsite and quartz sand, commonly used in oil and gas field fracturing. The salt is KCl. The solid particles added in the pre-fluid stage and the displacement fluid stage are salt particles, and the solid particles added in the low sand ratio stage and the main sand addition stage are proppant. The mass concentrations of polymer dry powder, dispersant and solid particles in fracturing fluid at each stage are shown in Table 1.

[0027] As shown in Table 1, the maximum volume ratio of polymer dry powder to solid particles is 5.0:100. At this ratio, the ratio of polymer to solid particles is still very large. Therefore, the proppant can effectively disperse the polymer dry powder in all stages of fracturing operations, thereby ensuring good dispersion, sufficient adhesion, and no fisheyes in the polymer dry powder.

[0028] Table 1: Addition of various reagents at different stages of fracturing S2. According to the proportion determined in step S1, the polymer dry powder, dispersant and solid particles are added to the dispersion and mixing mechanism of the proppant-assisted continuous mixing fracturing fluid device through the corresponding feed inlet. S3. The polymer dry powder continuously mixed fracturing fluid is processed by the proppant-assisted dispersion device and the prepared fracturing fluid is obtained from the outlet of the stirring mechanism (4).

[0029] In a fracturing fluid continuously mixed fracturing fluid device that uses proppant-assisted dispersion of polymer dry powder, raw materials are added to each feed inlet of the dispersion and mixing mechanism. The dispersion and mixing mechanism stirs and mixes the polymer dry powder. During the mixing process, the proppant is fully utilized to disperse, isolate, stir and grind the polymer dry powder, as well as the alcohol solution to disperse and spread the powder. This ensures that the solid particles, dispersant, and polymer dry powder are well mixed, ultimately achieving full dispersion and dissolution of the polymer dry powder in clean water.

[0030] During the implementation of fracturing in the mine, the amount of polymer dry powder and proppant added can be dynamically adjusted according to different stages of fracturing.

[0031] Application Example 1 This study focuses on a multi-stage volumetric fracturing horizontal well in a tight sandstone reservoir. The horizontal section is 1500m long, with a vertical depth of 2030m in the middle of the reservoir. The formation temperature is 65℃, the reservoir pressure is 18.1MPa, and the fracture closure pressure is 36.5MPa. The reservoir is a naturally fractured tight sandstone oil reservoir with a fracture density of 1.5~3.0 fractures / m, a porosity of 9.2%, and a permeability of 0.5mD. The reservoir has poor physical properties and requires volumetric fracturing to achieve economical production. A total of 15 fracturing stages were designed, with each stage requiring 5000m³ of fluid. 3 The construction discharge volume is 20m³. 3 / min. Therefore, to ensure the smooth implementation of on-site fracturing and reduce operating costs, polymer dry powder direct-mix fracturing fluid technology is designed and used as the fluid preparation technology. A continuous variable viscosity fracturing fluid is prepared using a proppant-assisted dispersed polymer dry powder continuous mixing fracturing fluid device and method. The first stage fracturing fluid preparation process for this multi-stage volumetric fracturing horizontal well is as follows: S1. Determine the fracturing fluid preparation procedure table and clarify the injection procedure for polymer dry powder, dispersant and solid particles, as shown in Table 2 below; Table 2: Chemical Addition Details at Different Stages of the First Stage of Multi-Stage Volumetric Fracturing in Horizontal Wells S2. Prepare materials according to the table above. This section of fracturing requires a total of 9.4t of polymer dry powder and 15m of dispersant. 3 450m of proppant 3 Dispersant selection; S3. Commence on-site operations. Following the fracturing fluid additive ratio in the table above, adjust the fracturing fluid discharge rate to 20m³. 3 The addition rate of each agent is determined by the speed of / min and the actual stage of fracturing construction. The proppant dispersant, dry powder thickener and solubilizer are added on site at the sand mixing truck using a proppant dispersant dry powder thickener solubilizer. S4. During the pre-fluidization construction stage, if the wellhead pressure is too high or the construction pressure curve is unstable, the concentration of polymer dry powder can be appropriately increased to no more than 0.06%. S5. Construction completed, pumps stopped, materials and equipment recovered.

[0032] This invention creatively proposes a concept for continuously mixing fracturing fluids using proppant as a dispersion medium. It designs a proppant dispersion dry powder thickener solubilizing device and implementation method. The device uses a combination of a screw-type stirring feeder and a double-cross oblique blade stirring paddle to improve the mixing effect. During fracturing operations, various solid / liquid phase materials required for fracturing fluid are added sequentially, thoroughly stirred, uniformly mixed, and sprinkled into a mixing tank to achieve continuous mixing of fracturing fluid.

[0033] The applicant declares that the above description is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Those skilled in the art should understand that any changes or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention fall within the protection and disclosure scope of the present invention.

Claims

1. A device for continuous mixing of proppant-assisted dispersed polymer dry powder fracturing fluid, characterized in that: It includes a power mechanism (1), a dispersing and mixing mechanism (2), a material distribution mechanism (3), and a stirring mechanism (4); The dispersion and mixing mechanism (2) includes a shell (201) and a screw-type stirring feeder (202) and two rows of stirring paddles disposed inside the shell (201); the upper part of the shell (201) is provided with a solid particle injection port (203), a dispersant injection port (204) and a polymer dry powder injection port (205); an outlet is provided at the lower part of the shell (201) near the material distribution mechanism (3); The material distribution mechanism (3) is a screw feeder with one inlet and multiple outlets (301); the lower outlet of the dispersion mixing mechanism (2) is located above the inlet of the material distribution mechanism (3); the outlet (301) is located above the mixing mechanism (4).

2. The proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device according to claim 1, characterized in that: The two rows of agitators are symmetrically arranged with the axis of the screw-type agitator feeder (204) as the center line, and the axes of the screw-type agitator feeder (202) and the two rows of agitators are arranged parallel to each other.

3. The proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device according to claim 1, characterized in that: The impeller is a double-cross oblique blade impeller, which includes a drive shaft (206) and multiple sets of impeller blades on the drive shaft (206); each impeller blade set includes two rows of impeller blades (207), and the plane of the impeller blades (207) and the axis of the drive shaft (206) are at angles of 45° and 135° respectively.

4. The proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device according to claim 1, characterized in that: The output shaft of the power mechanism (1) is connected to the rotating shaft and transmission shaft (206) of the screw-type stirring feeder (204).

5. The proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device according to claim 1, characterized in that: The mixing mechanism (4) is the mixing tank of the fracturing sand mixing truck.

6. The proppant-assisted dispersion polymer dry powder continuous mixing fracturing fluid device according to claim 1, characterized in that: The stirring mechanism (4) includes a tank (401) and a stirrer (402) disposed in the tank (401). The upper part of the tank (401) is provided with a liquid inlet (404), and the lower part of the tank (401) is provided with a discharge outlet (403).

7. A method for continuously mixing fracturing fluid with polymer dry powder using the proppant-assisted dispersion apparatus according to any one of claims 1 to 6, characterized in that: Includes the following steps: S1. Determine the fracturing stage and determine the mass concentrations of polymer dry powder, dispersant and solid particles in the fracturing fluid based on the fracturing stage; S2. According to the proportion determined in step S1, the polymer dry powder, dispersant and solid particles are added to the dispersion and mixing mechanism of the proppant-assisted continuous mixing fracturing fluid device through the corresponding feed inlet. S3. The polymer dry powder, dispersed with proppant, is continuously mixed and mixed with fracturing fluid. The prepared fracturing fluid is obtained from the outlet of the stirring mechanism.

8. The method for continuous mixing of proppant-assisted dispersed polymer dry powder into fracturing fluid according to claim 7, characterized in that: The fracturing stages include the pre-flush stage, the low sand ratio stage, the main sand addition stage, and the displacement fluid stage.

9. The method for continuous mixing of proppant-assisted dispersed polymer dry powder into fracturing fluid according to claim 8, characterized in that: The polymer powder has a mesh size of 60-100 mesh and a molecular weight of 16-22 million. 2 wt% urea is added to the polymer powder. The dispersant is a drainage aid solution or a clay stabilizer solution. The solid particles are proppant or salt particles. The proppant is 16-100 mesh ceramsite or quartz sand. The salt particles are KCl. The solid particles added during the pre-fluidization and displacement stages are salt particles, while the solid particles added during the low sand ratio stage and main sand addition stage are proppant.

10. The method for continuously mixing proppant-assisted dispersed polymer dry powder into fracturing fluid according to claim 8, characterized in that: The mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid during the pre-fracturing stage are 0.04%, 0.3%, and 2%, respectively; during the low sand ratio stage, the mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid are 0.15%, 0.3%, and 5%~15%, respectively; during the main sand addition stage, the mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid are 0.30%, 0.3%, and 15%~30%, respectively; and during the displacement fluid stage, the mass concentrations of polymer dry powder, dispersant, and solid particles in the fracturing fluid are 0.04%, 0.3%, and 2%, respectively.

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