Resin-coated quartz sand for fracturing and preparation method thereof

Abstract

The invention relates to a resin-coated quartz sand for fracturing and a preparation method thereof, which is applied in the field of oil extraction. The resin-coated quartz sand comprises the following ingredients in parts by weight: 100% of raw sand, 1.2%-2% of phenolic resin, 0.5%-1% of epoxy resin, 0.6%-0.8% of urotropine, 0.1%-0.3% of calcium stearate and 0.075%-0.1% of a curing agent. The compressive strength and flow conductivity of the coated sand are effectively improved by a composite coating method combining organic and inorganic materials. In the preparation process, a knocking rod is added to clean a blocked emulsion filter cartridge. The cleaning work is started by using the deflation work of the emulsion filter cartridge when it is blocked, and the efficient dust filtering work of the emulsion filter cartridge is effectively maintained. The heat carried by the gas is recovered by a heat exchange disk, and the waste heat utilization efficiency is effectively improved. The intercepting effect of a water-blocking bag is used to adaptively adjust the cold water supply after the blockage occurs, thereby effectively improving the heat recovery efficiency.

Description

Technical Field

[0001] The invention relates to resin-coated quartz sand for fracturing and a preparation method thereof, in particular to resin-coated quartz sand for fracturing applied in the field of petroleum exploitation and a preparation method thereof. Background Art

[0002] With the improvement of oil and gas extraction technology, oil and gas field development is moving towards deeper layers. In addition to vertical wells, there are also inclined wells and horizontal drilling. The deeper the reservoir, the greater the overburden pressure. In order to keep the artificial fractures opened by fracturing open, the current fracturing proppant uses coated sand, but most of them are organic films with limited compressive resistance.

[0003] In order to solve the problem of limited compressive resistance of organic coated sand, a certain coated sand in the market adopts the design of adding auxiliary materials and has a certain market share.

[0004] The Chinese patent CN201310125926.9 specification discloses a heat-resistant high-strength coated sand fracturing proppant and a preparation method thereof. The heat-resistant high-strength coated sand fracturing proppant is surface-modified by a silane coupling agent to improve the resin coating and bonding effect; the coated sand fracturing proppant is carried out in a low-viscosity solution, which can greatly reduce the energy consumption caused by the coating process compared with the traditional resin melting; the coated sand fracturing proppant of the present invention is polymerized in situ, so that the resin can form a more uniform and sufficient coating layer on the surface of quartz sand, thereby improving the heat resistance and compressive strength of the proppant. The heat resistance of the coated sand fracturing proppant of the present invention is above 200°C, and the crushing rate is below 2.5%. These properties are better than the existing commercially available coated sand, and the flow conductivity is also better under the same conditions. The coating process of the present invention has a better effect, and the resulting fracturing proppant has better heat resistance and compressive strength.

[0005] The Chinese patent CN202310808417.X specification discloses a high-strength coated sand and its preparation method and application. The high-strength coated sand is a loose particle prepared from raw materials containing raw sand, resin, toughening agent, curing agent and dispersant. The resin is a highly active polyphenol linear phenolic resin, the toughening agent is dioctyl ester, the weight ratio of the raw sand, the resin, the toughening agent, the curing agent and the dispersant is 100: 2-10: 0.04-2: 0.16-4: 0.14-0.7; the softening point of the highly active polyphenol linear phenolic resin is 50-120°C. The high-strength coated sand provided by the present invention can be secondary consolidated under the formation temperature and pressure conditions to form a sand barrier, and effectively support the cracks, effectively improve the problem of hydraulic fracturing proppant discharge, improve the construction effect of sand control and sand retaining measures, and prevent formation collapse.

[0006] Although the existing coated sand has added several auxiliary materials such as resin, curing agent, phenolic resin, etc., its anti-breakage ability and conductivity capacity are still limited. Moreover, the existing coated sand preparation process is not environmentally friendly and is prone to generate dust gas. Summary of the invention

[0007] In view of the above-mentioned prior art, the technical problem to be solved by the present invention is to improve the anti-crushing ability and conductivity of the coated sand, and to improve the environmental friendliness of the preparation process.

[0008] In order to solve the above problems, the present invention provides a resin-coated quartz sand for fracturing and a preparation method thereof, comprising the following ingredients in parts by weight: 100% of raw sand, 1.2%-2% of phenolic resin, 0.5%-1% of epoxy resin, 0.6%-0.8% of hexamethylenetetramine, 0.1%-0.3% of calcium stearate, and 0.075%-0.1% of a curing agent; The method for preparing resin-coated quartz sand for fracturing according to the above ingredients comprises the following steps: S1. First, dry 100% of the raw sand, and then put it into the heater with a measuring bucket for heating. After the raw sand is heated to 220-230℃, put it into the sand mixer; S2. During the sand mixing process, phenolic resin and epoxy resin are added respectively for two coatings, and auxiliary materials such as hexamethylenetetramine, calcium stearate, and curing agent are added. After sufficient mixing, coated sand is obtained, and then the coated sand is placed on a crushing screen for crushing and screening; S3. After crushing, the coated sand is placed in a boiling cooling bed for cooling. After the coated sand is cooled to below 25°C, it is screened and impurities are removed. Finally, it is put into storage after passing the test. Among them, the boiling cooling bed includes a main body, the main body includes a dust collecting hood, and the top of the dust collecting hood is connected to a conveying pipe, a dust filter box is installed above the conveying pipe, and both sides of the lower end of the dust filter box are fixedly connected with connecting pipes connected to the conveying pipe, the upper inner wall of the dust filter box is fixedly connected with a thermal insulation hood, the upper side wall of the dust filter box is fixedly connected with an exhaust hood connected to the thermal insulation hood, and an exhaust fan is installed inside the exhaust hood, the inner wall of the thermal insulation hood is fixedly connected with a heat exchange disk, and both side walls of the dust filter box are inserted with water pipes connected to the heat exchange disk, the lower end of the thermal insulation hood is connected to an emulsion filter cartridge, and the bottom of the dust filter box is also connected to two symmetrically distributed discharge cylinders.

[0009] In the above-mentioned resin-coated quartz sand for fracturing, the organic coating concept of conventional coated sand is broken through, and inorganic bonding is introduced to make the coating layer of the coated sand rigid. A composite coating method combining organic and inorganic is used to effectively improve the compressive resistance and conductivity of the coated sand.

[0010] As a further improvement of the present application, an elastic trigger head is fixedly connected to the bottom end of the emulsion filter cartridge, a mounting seat is fixedly connected to the bottom of the dust filter box located directly below the elastic trigger head, and an electromagnet is installed on the side wall of the mounting seat, and a pressure sensor electrically connected to the electromagnet is fixedly connected to the upper side wall of the mounting seat, the mounting seat is located on both side walls of the electromagnet and is rotatably connected to a rotating seat, and a knocking rod is fixedly embedded on the rotating seat, a magnetic driving pad is fixedly connected between the two knocking rods, and the magnetism of the magnetic driving pad repels the magnetism generated by the electromagnet, the magnetic driving pad includes an elastic layer, and a flexible magnetic pad is fixedly connected to the upper side wall of the elastic layer. In the process of cooling the coated sand with a boiling cooling bed, the exhaust fan inside the exhaust hood draws the dust-containing gas into the dust filter box, the emulsion filter cartridge filters the dust, and the purified gas exchanges heat with the heat exchange disk. The cooling water inside the disc changer absorbs the heat of the gas to achieve heat recovery. Due to the effect of heat, the dust will compact on the emulsion filter cartridge, which will cause the emulsion filter cartridge to be blocked. When blockage occurs, the gas permeability of the emulsion filter cartridge decreases, and the emulsion filter cartridge will become deflated under the action of the exhaust fan. After the emulsion filter cartridge becomes deflated, its length is stretched, which causes the elastic trigger head to press down on the pressure sensor. The pressure sensor starts the electromagnet to generate magnetic force, and the electromagnet repel the magnetic drive pad downward. The magnetic drive pad drives the two knocking rods to converge to the middle, so that the knocking rod will knock on the emulsion filter cartridge to knock down the compacted dust, thereby cleaning the emulsion filter cartridge. When the electromagnet is turned off, the rebound force of the magnetic drive pad will reset the knocking rod. By controlling the repeated start and stop of the electromagnet, the knocking rod can repeatedly knock on the emulsion filter cartridge.

[0011] As a further improvement of the present application, an elastic connecting gasket is fixedly connected between the thermal insulation cover and the emulsion filter cartridge. The elastic connecting gasket includes multiple flexible wrapping shells, and a rubber pad is fixedly connected between two adjacent flexible wrapping shells. The interior of the flexible wrapping shell is filled with a rubber filling layer. The elastic connecting gasket realizes the elastic connection between the emulsion filter cartridge and the thermal insulation cover. In this way, when the knocking rod knocks the emulsion filter cartridge, the emulsion filter cartridge can vibrate, thereby further effectively improving the self-cleaning effect of the emulsion filter cartridge. Moreover, after the emulsion filter cartridge is blocked, the elastic connection effect of the elastic connecting gasket also prevents the emulsion filter cartridge from becoming deflated.

[0012] As a further improvement of the present application, the heat exchange plate includes a hollow plate body, and a plurality of air holes evenly distributed at equal intervals are provided on the hollow plate body. Water ports connected to water pipes are provided on both side walls of the hollow plate body. An external water supply system supplies cold water to the interior of the hollow plate body through the water pipe. When the filtered gas passes through the hollow plate body, the cold water absorbs the heat in the gas, thereby realizing heat recovery.

[0013] As another improvement of the present application, the pipe near the water inlet end of the water pipe is also connected to a water control tank, the inner wall of the water control tank is provided with a control cavity, and the inner wall of the control cavity is fixedly inlaid with a water pipe connected to the water pipe, the inner wall of the control cavity is installed with an electric telescopic rod electrically connected to the pressure sensor, and the inner wall of the control cavity is placed with an air storage bag connected to the output end of the electric telescopic rod, the inner wall of the water pipe is fixedly connected with a water blocking bag connected to the air storage bag, after the emulsion filter cartridge is blocked, the amount of gas for heat exchange with the heat exchange disk is reduced, and if the original water supply is to be maintained. The efficiency of gas heat recovery will be reduced because it is not easy for a large amount of cold water to release the heat after absorbing a small amount of heat. Therefore, when the elastic trigger head triggers the pressure sensor to start the electromagnet, the pressure sensor also starts the electric telescopic rod. The two electric telescopic rods squeeze the air storage bag at the same time, so that the gas inside the air storage bag is squeezed into the water blocking bag. The water blocking bag expands after being filled with gas, so as to intercept the cold water flowing through the water pipe. In this way, the supply of cold water can be adaptively reduced in coordination with the blockage, thereby effectively improving the heat recovery efficiency.

[0014] As another improved supplement of the present application, the water-blocking bag includes a pressure-resistant disc, and an elastic air bag is fixedly connected to the pressure-resistant disc. When the air storage bag is pressurized, gas is filled into the water-blocking bag to expand it, thereby intercepting the cold water.

[0015] In summary, the compressive strength and flow conductivity of the coated sand are effectively improved by a composite coating method combining organic and inorganic elements. In the preparation process, a knocking rod is added to clean the blocked emulsion filter cartridge. The deflation of the emulsion filter cartridge when blocked is used to start the cleaning work, effectively maintaining the high-efficiency dust filtering work of the emulsion filter cartridge. The heat carried by the gas is recovered through the heat exchange plate to effectively improve the utilization efficiency of waste heat. The intercepting effect of the water-blocking bag is used to adaptively adjust the cold water supply after blockage, thereby effectively improving the heat recovery efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a flow chart of the preparation method of the first embodiment of the present application; Figure 2 This is a three-dimensional diagram of a boiling cooling bed according to a first embodiment of the present application; Figure 3 This is a working state diagram of the dust filter box of the second embodiment of the present application during dust filtering; Figure 4 This is a working state diagram of the dust filter box of the second embodiment of the present application during cleaning; Figure 5 This is a three-dimensional diagram of a milky filter cartridge according to a first embodiment of the present application; Figure 6 A three-dimensional diagram of a knocking rod according to a second embodiment of the present application; Figure 7 A three-dimensional diagram of a heat exchange disk according to a first embodiment of the present application; Figure 8 for Figure 3 A magnified view of the structure at center A; Fig. 9 for Figure 4 A magnified view of the structure at B in the middle; Fig.10 This is a front cross-sectional view of the elastic connecting gasket of the second embodiment of the present application.

[0017] Description of the numbers in the figure: 1 main body, 101 dust collecting hood, 102 conveying pipe, 2 dust filter box, 3 connecting pipe, 4 insulation cover, 5 exhaust hood, 6 heat exchange plate, 601 hollow plate body, 602 air vent, 603 water outlet, 7 water pipe, 8 emulsion filter cartridge, 9 elastic trigger head, 10 mounting seat, 11 electromagnet, 12 pressure sensor, 13 rotating seat, 14 knocking rod, 15 magnetic drive pad, 16 discharge barrel, 17 elastic connecting gasket, 1701 flexible wrapping shell, 1702 rubber pad, 1703 rubber filling layer, 18 water control tank, 1801 control chamber, 19 water pipe, 20 electric telescopic rod, 21 air storage bag, 22 water blocking bag. DETAILED DESCRIPTION

[0018] Two implementation modes of the present application are described in detail below with reference to the accompanying drawings.

[0019] The first implementation method: Figure 1 It is shown that the following ingredients are included in parts by weight: 100% of raw sand, 1.2%-2% of phenolic resin, 0.5%-1% of epoxy resin, 0.6%-0.8% of hexamethylenetetramine, 0.1%-0.3% of calcium stearate, and 0.075%-0.1% of curing agent; The method for preparing resin-coated quartz sand for fracturing according to the above ingredients comprises the following steps: S1. First, dry 100% of the raw sand, and then put it into the heater with a measuring bucket for heating. After the raw sand is heated to 220-230℃, put it into the sand mixer; S2. During the sand mixing process, phenolic resin and epoxy resin are added respectively for two coatings, and auxiliary materials such as hexamethylenetetramine, calcium stearate, and curing agent are added. After sufficient mixing, coated sand is obtained, and then the coated sand is placed on a crushing screen for crushing and screening; S3. After crushing, the coated sand is placed in a boiling cooling bed for cooling. After the coated sand is cooled to below 25°C, it is screened and impurities are removed. Finally, it is put into storage after passing the test. Figure 2 , 5 and Figure 7 As shown, the boiling cooling bed includes a body 1, the body 1 includes a dust collecting cover 101, and the top of the dust collecting cover 101 is connected to a conveying pipe 102, a dust filter box 2 is installed above the conveying pipe 102, and both sides of the lower end of the dust filter box 2 are fixedly connected with connecting pipes 3 connected to the conveying pipe 102, the upper inner wall of the dust filter box 2 is fixedly connected with a heat insulation cover 4, the upper side wall of the dust filter box 2 is fixedly connected with an exhaust cover 5 connected to the heat insulation cover 4, and an exhaust fan is installed inside the exhaust cover 5 (the specific model is selected according to actual needs and is not described in detail here), the inner wall of the heat insulation cover 4 is fixedly connected with a heat exchange plate 6, and the heat exchange plate 6 includes a hollow plate body 601 (preferably a metal material with high thermal conductivity, and other materials can also be selected according to actual needs). Quality), and a plurality of air holes 602 evenly distributed at equal intervals are provided on the hollow disk body 601, and water ports 603 connected to the water pipe 7 are provided on both side walls of the hollow disk body 601, and the external water supply system supplies cold water to the inside of the hollow disk body 601 through the water pipe 7. When the filtered gas passes through the hollow disk body 601, the cold water absorbs the heat in the gas, thereby realizing heat recovery, and water pipes 7 connected to the heat exchange disk 6 are inserted on both side walls of the dust filter box 2, and the water pipes 7 are connected to the external circulating water supply system, one water pipe 7 is a water supply pipe, and the other water pipe 7 is a return pipe, the lower end of the temperature insulation cover 4 is connected to an emulsion-shaped filter cartridge 8, and the bottom of the dust filter box 2 is also connected to two symmetrically distributed discharge barrels 16.

[0020] The second implementation method: Figure 3 , 4 and Figure 6As shown, the bottom end of the emulsion filter cartridge 8 is fixedly connected with an elastic trigger head 9 (preferably made of rubber, and other materials can also be selected according to actual needs), the bottom of the dust filter box 2 located directly below the elastic trigger head 9 is fixedly connected with a mounting seat 10, and an electromagnet 11 is installed on the side wall of the mounting seat 10 (the specific model is selected according to actual needs and is not described in detail here), and the upper side wall of the mounting seat 10 is fixedly connected with a pressure sensor 12 electrically connected to the electromagnet 11 (the specific model is selected according to actual needs and is not described in detail here), and the mounting seat 10 is located on both side walls of the electromagnet 11, and the rotating seat 13 is rotatably connected, and the rotating seat 13 is fixedly inlaid with a knocking rod 14, and a magnetic driving pad 15 is fixedly connected between the two knocking rods 14, and the magnetism of the magnetic driving pad 15 repels the magnetism generated by the electromagnet 11, and the magnetic driving pad 15 includes an elastic layer (preferably a polyurethane elastic material, and other materials can also be selected according to actual needs), and the upper side wall of the elastic layer is fixedly connected with a flexible magnetic pad. In the process of cooling the coated sand with a boiling cooling bed, the exhaust fan inside the exhaust hood 5 will The gas containing dust is drawn into the dust filter box 2, and the emulsion filter cartridge 8 filters the dust. The purified gas exchanges heat with the heat exchange disk 6, and the cooling water inside the heat exchange disk 6 absorbs the heat of the gas, thereby realizing heat recovery. Due to the effect of heat, the dust will be agglomerated on the emulsion filter cartridge 8, thereby causing the emulsion filter cartridge 8 to be blocked. When blockage occurs, the gas permeability of the emulsion filter cartridge 8 decreases, and the emulsion filter cartridge 8 will become deflated under the action of the exhaust fan. After the emulsion filter cartridge 8 becomes deflated, its length is stretched, thereby causing the elastic trigger head 9 to be pressed down at the pressure. On the sensor 12, the pressure sensor 12 starts the electromagnet 11 to generate magnetic force, and the electromagnet 11 magnetically repels the magnetic driving pad 15 downward, and the magnetic driving pad 15 drives the two knocking rods 14 to retract toward the middle, so that the knocking rod 14 will knock the milky filter cartridge 8, thereby knocking down the compacted dust, thereby playing the role of cleaning the milky filter cartridge 8. When the electromagnet 11 is turned off, the rebound force of the magnetic driving pad 15 will reset the knocking rod 14. By controlling the repeated start and stop of the electromagnet 11, the knocking rod 14 can be repeatedly knocked on the milky filter cartridge 8; Fig.10As shown, an elastic connection gasket 17 is also fixedly connected between the insulation cover 4 and the milky filter cartridge 8. The elastic connection gasket 17 includes a plurality of flexible wrapping shells 1701 (preferably heat-resistant silicone material, and other materials can also be selected according to actual needs), and a rubber pad 1702 is fixedly connected between two adjacent flexible wrapping shells 1701. The interior of the flexible wrapping shell 1701 is filled with a rubber filling layer 1703. The elastic connection gasket 17 realizes the elastic connection between the milky filter cartridge 8 and the insulation cover 4. In this way, when the knocking rod 14 knocks the milky filter cartridge 8, the milky filter cartridge 8 can vibrate, thereby further effectively improving the self-cleaning effect of the milky filter cartridge 8. Moreover, after the milky filter cartridge 8 is blocked, the elastic connection effect of the elastic connection gasket 17 also prevents the milky filter cartridge 8 from becoming deflated. Figure 8 , 9 As shown, the pipe near the water inlet end of the water pipe 7 is also connected to a water control tank 18, the inner wall of the water control tank 18 is provided with a control chamber 1801, and the inner wall of the control chamber 1801 is fixedly inlaid with a water pipe 19 connected to the water pipe 7, the inner wall of the control chamber 1801 is installed with an electric telescopic rod 20 (the specific model is selected according to actual needs and is not described in detail here), and the inner wall of the control chamber 1801 is placed with an air storage bag 21 connected to the output end of the electric telescopic rod 20, the inner wall of the water pipe 19 is fixedly connected with a water blocking bag 22 connected to the air storage bag 21, the water blocking bag 22 includes a pressure-resistant disc, and the pressure-resistant disc is fixedly connected with an elastic air bag, and after the air storage bag 21 is pressurized, gas is filled into the water blocking bag 22 to expand it. Thereby, the cold water is intercepted. After the emulsion filter cartridge 8 is blocked, the amount of gas that exchanges heat with the heat exchange disk 6 is reduced. If the original water supply is to be maintained, the efficiency of gas heat recovery will be reduced, because it is not easy for a large amount of cold water to release the heat after absorbing a small amount of heat. Therefore, the elastic trigger head 9 triggers the pressure sensor 12 to start the electromagnet 11. At the same time, the pressure sensor 12 also starts the electric telescopic rod 20. The two electric telescopic rods 20 squeeze the air storage bag 21 at the same time, so that the gas inside the air storage bag 21 is squeezed into the water blocking bag 22. The water blocking bag 22 is filled with gas and expands, so as to intercept the cold water flowing through the water pipe 19. In this way, the supply of cold water can be adaptively reduced in coordination with the blockage, thereby effectively improving the heat recovery efficiency.

[0021] In view of current practical needs, the above-mentioned implementation mode adopted in this application is not limited to the scope of protection. Various changes made within the knowledge scope of technical personnel in this field without departing from the concept of this application still fall within the scope of protection of the present invention.

Claims

1. A resin-coated quartz sand for fracturing, characterized in that: The invention comprises the following ingredients in parts by weight: 100% of raw sand, 1.2%-2% of phenolic resin, 0.5%-1% of epoxy resin, 0.6%-0.8% of hexamethylenetetramine, 0.1%-0.3% of calcium stearate, and 0.075%-0.1% of curing agent; The method for preparing resin-coated quartz sand for fracturing according to the above ingredients comprises the following steps: S1. First, dry 100% of the raw sand, and then put it into the heater with a measuring bucket for heating. After the raw sand is heated to 220-230℃, put it into the sand mixer; S2. During the sand mixing process, phenolic resin and epoxy resin are added respectively for two coatings, and auxiliary materials such as hexamethylenetetramine, calcium stearate, and curing agent are added. After sufficient mixing, coated sand is obtained, and then the coated sand is placed on a crushing screen for crushing and screening; S3. After crushing, the coated sand is placed on a boiling cooling bed for cooling. After the coated sand is cooled to below 25°C, it is screened and impurities are removed. Finally, it is put into storage after passing the test. The fluidized bed cooler comprises a main body (1), the main body (1) comprising a dust collecting hood (101), the top of the dust collecting hood (101) being connected to a delivery pipe (102), a dust filter box (2) being installed above the delivery pipe (102), and both sides of the lower end of the dust filter box (2) being fixedly connected to connecting pipes (3) connected to the delivery pipe (102), a thermal insulation hood (4) being fixedly connected to the inner wall of the upper end of the dust filter box (2), and the upper end of the dust filter box (2) being fixedly connected to the inner wall of the upper end of the dust filter box (2). An exhaust hood (5) connected to the heat-insulating hood (4) is fixedly connected to the end side wall, and an exhaust fan is installed inside the exhaust hood (5). A heat exchange disk (6) is fixedly connected to the inner wall of the heat-insulating hood (4), and water pipes (7) connected to the heat exchange disk (6) are inserted into the side walls of the dust filter box (2). The lower end of the heat-insulating hood (4) is connected to an emulsion filter cartridge (8), and the bottom of the dust filter box (2) is also connected to two symmetrically distributed discharge cylinders (16).

2. The method for preparing resin-coated quartz sand for fracturing according to claim 1, characterized in that: The bottom end of the milky filter cartridge (8) is fixedly connected to an elastic trigger head (9); the bottom of the dust filter box (2) located directly below the elastic trigger head (9) is fixedly connected to a mounting seat (10), and an electromagnet (11) is mounted on the side wall of the mounting seat (10); the upper side wall of the mounting seat (10) is fixedly connected to a pressure sensor (12) electrically connected to the electromagnet (11); both side walls of the mounting seat (10) located on the electromagnet (11) are rotatably connected to a rotating seat (13), and a knocking rod (14) is fixedly embedded on the rotating seat (13); a magnetic drive pad (15) is fixedly connected between the two knocking rods (14), and the magnetism of the magnetic drive pad (15) repels the magnetism generated by the electromagnet (11); the magnetic drive pad (15) comprises an elastic layer, and the upper side wall of the elastic layer is fixedly connected to a flexible magnetic pad.

3. The method for preparing resin-coated quartz sand for fracturing according to claim 2, characterized in that: An elastic connection gasket (17) is also fixedly connected between the thermal insulation cover (4) and the milky filter cartridge (8), the elastic connection gasket (17) comprising a plurality of flexible wrapping shells (1701), a rubber pad (1702) is fixedly connected between two adjacent flexible wrapping shells (1701), and the interior of the flexible wrapping shell (1701) is filled with a rubber filling layer (1703).

4. The method for preparing resin-coated quartz sand for fracturing according to claim 1, characterized in that: The heat exchange plate (6) comprises a hollow plate body (601), and a plurality of air holes (602) evenly distributed at equal intervals are provided on the hollow plate body (601), and water ports (603) connected to the water pipe (7) are provided on both side walls of the hollow plate body (601).

5. The method for preparing resin-coated quartz sand for fracturing according to claim 2, characterized in that: The water pipe (7) is also connected to a water control box (18) on the pipe near the water inlet end, the inner wall of the water control box (18) is provided with a control chamber (1801), and the inner wall of the control chamber (1801) is fixedly inlaid with a water pipe (19) connected to the water pipe (7), the inner wall of the control chamber (1801) is equipped with an electric telescopic rod (20) electrically connected to the pressure sensor (12), and the inner wall of the control chamber (1801) is provided with an air storage bag (21) connected to the output end of the electric telescopic rod (20), and the inner wall of the water pipe (19) is fixedly connected with a water blocking bag (22) connected to the air storage bag (21).

6. The method for preparing resin-coated quartz sand for fracturing according to claim 5, characterized in that: The water-blocking bag (22) comprises a pressure-resistant disc, and an elastic air bag is fixedly connected to the pressure-resistant disc.

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