A flat gate valve for shale gas layer fracturing and a working method thereof

Abstract

The present application provides a kind of shale gas layer fracturing flat gate valve and its working method, relate to oil and gas exploitation mechanical equipment field, the shale gas layer fracturing flat gate valve includes: valve body, main fluid passage and guide groove are set in the valve body, main fluid passage penetrates valve body, one end of guide groove is opened in the outer wall surface of valve body, the other end of guide groove is closed;Valve core has sequentially arranged driving section, communication section and closed section, inner hole is opened in communication section and is along the radial hole of valve core, valve core is arranged in guide groove and is sealed with the inner wall of guide groove Sliding fit, valve core has opening position and cleaning position, when valve core is located in opening position, communication section is located at the intersection of main fluid passage and guide groove and is connected with main fluid passage, when valve core is located in cleaning position, communication section moves to the outside of valve body and closed section cuts off main fluid passage.The shale gas layer fracturing flat gate valve and its working method can greatly improve the cleaning efficiency of valve core.

Description

Technical Field

[0001] 5 This invention relates to the field of oil and gas extraction machinery and equipment, and particularly to a flat gate valve for fracturing shale gas formations and its working method. Background Technology

[0002] In the extraction of shale gas, fracturing fluid needs to be pumped into the shale gas reservoir to improve its structure, thereby facilitating subsequent extraction of shale gas. During the process of delivering fracturing fluid to the shale gas reservoir, it is necessary to...

[0003] A flat gate valve is used, connected between the top port of the wellbore and the discharge port of the high-pressure pump. In use, the operator first connects one port of the flat gate valve to the top port of the wellbore, then connects the other port to the discharge port of the high-pressure pump. The high-pressure pump is then turned on, drawing fracturing fluid from the outside and pumping it into the flat gate valve.

[0004] The flat gate valve enters the wellbore and eventually enters the shale gas layer. After the fracturing fluid is injected, the worker closes the flat gate valve. The valve core 5 of the flat gate valve cuts off the flow channel, thereby preventing the injected fracturing fluid from flowing back.

[0005] While existing flat gate valves are widely used in shale gas extraction, they still have the following technical shortcomings:

[0006] Firstly, with prolonged use, a large amount of dirt accumulates on the inner wall of the inner bore 8 of the valve core 5 of the flat gate valve. This dirt hinders the delivery of fracturing fluid. To clean away the dirt, the worker's procedure is to first disassemble the flat gate valve...

[0007] First, the valve core 5 is removed, and the dirt adhering to the inner wall of the inner hole 8 of the valve core 5 is cleaned off. After cleaning, the worker 20 reinstalls the valve core 5. Although this removes the dirt, it undoubtedly adds a cleaning process, thus greatly reducing the cleaning efficiency of the valve core 5. In addition, manual cleaning is required, which increases the workload of the workers. Secondly, if the valve core 5 is damaged in the closed state, that is, if the valve core 5 is damaged after cutting off the two ports of the flat gate valve, the fracturing fluid cannot be delivered into the well, thus making it impossible to continue fracturing the shale formation.

[0008] In view of this, based on years of experience in production and design in this and related fields, the inventor has designed a flat gate valve for shale gas fracturing and its working method after 25 repeated experiments, in order to solve the problems existing in the prior art. Summary of the Invention

[0009] The purpose of this invention is to provide a flat gate valve for shale gas fracturing and its working method, which can greatly improve the valve core cleaning efficiency.

[0010] To achieve the above objectives, the present invention proposes a flat gate valve for fracturing shale gas reservoirs, wherein the flat gate valve for fracturing shale gas reservoirs comprises:

[0011] The valve body has a main fluid channel and a guide groove that intersect inside it. The main fluid channel passes through the valve body, and one end of the guide groove opens onto the outer wall of the valve body, while the other end of the guide groove is closed.

[0012] The valve core has a drive section, a connecting section, and a closing section arranged in sequence. The connecting section has an inner hole that extends radially through the valve core. The valve core passes through the guide groove and slides in a sealing fit with the inner wall of the guide groove. The valve core has an open position and a cleaning position. When the valve core is in the open position, the connecting section is located at the intersection of the main fluid channel and the guide groove and connects to the main fluid channel. When the valve core is in the cleaning position, the connecting section moves to the outside of the valve body and the closing section blocks the main fluid channel.

[0013] The shale gas fracturing flat gate valve also includes a valve cylinder (3) for driving the valve core (5) to slide back and forth. The valve cylinder (3) is fixedly connected to the valve body (1) by a bracket (2), and the piston rod of the valve cylinder (3) is fixedly connected to the driving section of the valve core (5).

[0014] The shale gas fracturing plate gate valve also includes a cleaning mechanism, which includes an infusion pipe, a spray pipe and a drain pipe (21). The infusion pipe and the drain pipe (21) are installed on the bracket (2) and located on both sides of the valve core (2). When the valve core (2) is in the cleaning position, the infusion pipe and the drain pipe (21) are aligned with the inner hole. The spray pipe is located at the end of the infusion pipe and can spray cleaning fluid into the inner hole.

[0015] The valve body (1) is also provided with a flow guide channel. Both ends of the flow guide channel are connected to the main fluid channel and are located on opposite sides of the valve core (1). The flow guide channel and the guide groove (4) are not connected to each other.

[0016] The valve body (1) is provided with a blocking mechanism (12) that can control the connection and disconnection of the flow channel.

[0017] The blocking mechanism (12) includes a gantry frame (22), a drive cylinder (25), and a plug (23). An installation channel is also provided inside the valve body (1). One end of the installation channel is connected to the flow channel, and the other end of the installation channel opens into the outer wall of the valve body (1). The gantry frame (22) is fixed on the valve body (1) and aligns with the opening. The drive cylinder (25) is fixed on the gantry frame (22), and the piston rod of the drive cylinder (25) passes through the installation channel. The plug (23) is fixed at the end of the piston rod and slides in a sealed manner with the installation channel. The plug (23) can extend into the flow channel under the drive of the piston rod and isolate the flow channel.

[0018] This invention also proposes a method for operating a flat gate valve for fracturing shale gas formations. The method involves placing the flat gate valve, as described above, at the wellhead. One end of the main fluid channel is connected to the wellhead, and the other end is connected to the fracturing fluid pump. The valve core is positioned in the open position. The fracturing fluid pump delivers fracturing fluid to the wellhead through the main fluid channel. After delivering a predetermined amount of fracturing fluid, the valve core is positioned in the cleaning position, and the inner bore of the valve core is cleaned.

[0019] Compared with the prior art, the present invention has the following features and advantages:

[0020] The flat gate valve for shale gas fracturing and its working method proposed in this invention have a valve core connecting section that can be moved to the outside of the valve body. Compared with traditional disassembly cleaning, the valve core can be cleaned online without disassembly and assembly, thereby greatly improving the cleaning efficiency of valve dirt. Attached Figure Description

[0021] The accompanying drawings described herein are for illustrative purposes only and are not intended to limit the scope of the invention in any way. Furthermore, the shapes and proportions of the components in the drawings are merely illustrative to aid in understanding the invention and do not specifically limit the shapes and proportions of the components. Those skilled in the art, guided by the teachings of this invention, can select various possible shapes and proportions to implement the invention according to specific circumstances.

[0022] Figure 1 This is a schematic diagram of the flat gate valve structure for shale gas fracturing according to the present invention;

[0023] Figure 2 for Figure 1 AA section view;

[0024] Figure 3 for Figure 1 The left view;

[0025] Figure 4 This is a schematic diagram of the valve body in this invention;

[0026] Figure 5 This is a schematic diagram of the cleaning mechanism in this invention;

[0027] Figure 6 This is a schematic diagram of the blocking mechanism in this invention;

[0028] Figure 7 This is a schematic diagram showing how the valve core cuts off the inlet and outlet in this invention;

[0029] Figure 8 This is a schematic diagram of the inner hole of the conical nozzle cleaning valve core of the cleaning mechanism in this invention;

[0030] Figure 9 This is a schematic diagram of the plug opening in this invention.

[0031] Explanation of reference numerals in the attached figures:

[0032] 1. Valve body; 2. Bracket; 3. Valve cylinder; 4. Guide groove; 5. Valve core; 6. Outlet; 7. Inlet; 8. Inner hole; 9. Vertical channel section; 10. Horizontal channel section; 11. Bypass channel section; 12. Blocking mechanism; 13. Cleaning mechanism; 14. Feed cylinder; 15. Push plate; 16. Straight pipe; 17. Conical nozzle; 18. Spray hole; 19. Connector; 20. Support frame; 21. Drain pipe; 22. Gantry frame; 23. Plug; 24. Hose; 25. Drive cylinder. Detailed Implementation

[0033] The details of the present invention can be more clearly understood by referring to the accompanying drawings and the description of specific embodiments. However, the specific embodiments of the present invention described herein are for illustrative purposes only and should not be construed as limiting the invention in any way. Under the teachings of this invention, those skilled in the art can conceive of any possible modifications based on the invention, and these should all be considered to fall within the scope of the invention.

[0034] like Figures 1 to 9As shown, this invention proposes a flat gate valve for fracturing shale gas reservoirs. The flat gate valve for fracturing shale gas reservoirs includes a valve body 1 and a valve core 5. The valve body 1 has a main fluid channel and a guide groove 4 that are intersected. The main fluid channel passes through the valve body 1. One end of the guide groove 4 is open to the outer wall of the valve body 1, and the other end of the guide groove 4 is closed. The valve core 5 has a drive section, a connecting section and a closing section arranged in sequence. The connecting section has an inner hole 8 that passes through the valve core 5 radially. The valve core 5 passes through the guide groove 4 and is sealed and slides in cooperation with the inner wall of the guide groove 4. The valve core 5 has an open position and a cleaning position. When the valve core 5 is in the open position, the connecting section is located at the intersection of the main fluid channel and the guide groove 4 and connects to the main fluid channel. When the valve core 5 is in the cleaning position, the connecting section moves outside the valve body 1 and the closing section blocks the main fluid channel.

[0035] This invention also proposes a working method for a flat gate valve used in shale gas fracturing. The flat gate valve is installed at the wellhead, with one end of the main fluid channel connected to the wellhead and the other end connected to the fracturing fluid pump. The valve core 5 is in the open position, and the fracturing fluid pump delivers fracturing fluid to the wellhead through the main fluid channel. After delivering a predetermined amount of fracturing fluid, the valve core 5 is placed in the cleaning position to clean the inner hole 8 of the valve core 5.

[0036] The flat gate valve for shale gas fracturing and its working method proposed in this invention have a valve core 5 whose connecting section can be moved to the outside of the valve body 1. Compared with the traditional disassembly cleaning, the valve core 5 can be cleaned online without disassembling and assembling the valve core 55, thereby greatly improving the cleaning efficiency of valve dirt.

[0037] The flat gate valve for shale gas fracturing proposed in this invention has a compact structure and greatly improves the cleaning efficiency of the valve core inner hole.

[0038] In an optional embodiment of the present invention, the flat gate valve for fracturing shale gas reservoirs further includes a valve cylinder 3 for driving the valve core 5 to slide back and forth. The valve cylinder 3 is fixedly connected to the valve body 1 via a bracket 2, and the piston rod of the valve cylinder 3 is fixedly connected to the driving section of the valve core 5.

[0039] In an optional embodiment of the present invention, the flat gate valve for fracturing shale gas formation further includes a cleaning mechanism 13. The cleaning mechanism 13 includes a liquid delivery pipe, a spray pipe, and a drain pipe 21. The liquid delivery pipe and the drain pipe 21 are mounted on the bracket 2 and are located on both sides of the valve core 5, respectively. When the valve core 5 is in the cleaning position, the liquid delivery pipe and the drain pipe 21 are aligned and cooperate with the inner hole 8. The spray pipe is located at the end of the liquid delivery pipe and can spray cleaning fluid into the inner hole 8.

[0040] In one optional example of this embodiment, the nozzle is a conical nozzle with multiple injection holes on its sidewall.

[0041] Furthermore, the injection hole is inclined toward the inner hole 8.

[0042] In an optional example of this embodiment, the cleaning mechanism 13 further includes a feed cylinder 14 and a push plate 15. The feed cylinder 14 is fixedly connected to the bracket 2, the push plate 15 is fixedly connected to the piston rod of the feed cylinder 14, and the infusion tube is fixedly connected to the push plate 15. The infusion tube can move toward the inner hole 8 under the drive of the piston rod.

[0043] In one optional embodiment, the infusion tubing includes a straight section and a flexible section, the straight section being fixed to the push plate 15 and the flexible section being connected to the cleaning fluid pump.

[0044] In an optional embodiment of the present invention, a flow guiding channel is further provided inside the valve body 1. Both ends of the flow guiding channel are connected to the main fluid channel and are located on opposite sides of the valve core 5, respectively. The flow guiding channel and the guide groove 4 are not connected to each other. With the above structure, even if the valve core 5 is damaged, the fracturing fluid can still be transported to the wellhead through the flow guiding channel, ensuring the normal progress of fracturing operations.

[0045] In an optional example of this embodiment, the valve body 1 is provided with a blocking mechanism 12 capable of controlling the connection and disconnection of the flow channel.

[0046] In an optional example, the blocking mechanism 12 includes a gantry 22, a drive cylinder 25, and a plug 23. An installation channel is also provided inside the valve body 1. One end of the installation channel is connected to the flow channel, and the other end of the installation channel opens onto the outer wall of the valve body 1. The gantry 22 is fixed to the valve body 1 and is aligned with the opening. The drive cylinder 25 is fixed to the gantry 22, and the piston rod of the drive cylinder 25 passes through the installation channel. The plug 23 is fixed to the end of the piston rod and is in a sealing sliding fit with the installation channel. The plug 23 can extend into the flow channel under the drive of the piston rod and block the flow channel.

[0047] In an optional example of this implementation, the flow channel includes a vertical channel section 9, a horizontal channel section 1010, and a bypass channel section 11. One end of the vertical channel section 9 is connected to the main fluid channel, and the other end of the vertical channel section 9 is connected to one end of the horizontal channel section 1010. The horizontal channel section 1010 is perpendicular to the vertical channel section 9, and the other end of the horizontal channel section 1010 is connected to one end of the bypass channel. The other end of the bypass channel is connected to the main fluid channel, and the installation channel is connected to the horizontal channel.

[0048] In an optional embodiment of the present invention, one end of the main fluid channel is an inlet and the other end is an outlet.

[0049] Please refer to Figures 1 to 9The following is a detailed description of the specific implementation process of the flat gate valve for shale gas fracturing and its working method proposed in this invention, with reference to an embodiment:

[0050] In this embodiment, the flat gate valve for shale gas fracturing includes a valve body 1 and a bracket 2 fixed to the top of the valve body 1. Multiple support frames 20 are fixed to the bottom surface of the valve body 1, and each support frame 20 has mounting holes. A valve cylinder 3 is fixed to the top of the bracket 2. A guide groove 4 is provided on the top of the valve body 1, and a valve core 5 is slidably installed within the guide groove 4. The piston rod of the valve cylinder 3 passes through the bracket 2 and is fixedly connected to the valve core 5. An outlet 6 and an inlet 7 are respectively provided on the left and right side walls of the valve body 1. The inlet 7 and outlet 6 are symmetrically arranged about the inner hole 8 of the valve core 5. Both the liquid inlet 7 and the liquid outlet 6 are connected to a connector 19. Both the liquid outlet 6 and the liquid inlet 7 are connected to the inner hole 8 of the valve core 5. An L-shaped channel is also provided in the valve body 1 on the left side of the guide groove 4. The vertical channel section 9 of the L-shaped channel is connected to the liquid outlet 6. The horizontal channel section 10 of the L-shaped channel is set through the right side wall of the valve body 1. A bypass channel section 11 is provided in the valve body 1 on the right side of the guide groove 4. The upper port of the bypass channel section 11 is connected to the liquid inlet 7, and the lower port of the bypass channel section 11 is connected to the horizontal channel 10. A blocking mechanism 12 is provided at the right port of the horizontal channel section 10.

[0051] A cleaning mechanism 13 is provided on the side plate of the support 2. The cleaning mechanism 13 includes a feed cylinder 14 fixed to the left side plate of the support 2. A push plate 15 is welded to the working end of the piston rod of the feed cylinder 14. A straight section 16 of the infusion tube is welded to the push plate 15. A hose section 24 is connected to the left end of the straight section 16, and a spray pipe 17 is connected to the right end of the straight section 16. The spray pipe 17 is located to the left of the valve core 5. The diameter of the large end face of the spray pipe 17 is smaller than the inner diameter of the valve core 5. Multiple spray holes 18 communicating with the spherical surface of the spray pipe 17 are opened. The spray holes 18 are inclined to the right. A drain pipe 21 is welded to the right side plate of the support 2. The drain pipe 21 and the spray pipe 17 are arranged opposite each other. The left end face of the drain pipe 21 is flush with the right end face of the valve core 5 in the vertical direction. The blocking mechanism 12 includes a gantry 22 fixed on the right end face of the valve body 1. A drive cylinder 25 is fixed on the crossbeam of the gantry 22. The piston rod of the drive cylinder 25 passes through the crossbeam and extends into the horizontal channel 10. A plug 23 is fixed on the extended end of the drive cylinder 25 to block the lower port of the bypass channel 11.

[0052] The operating method of this flat gate valve for shale gas fracturing includes the following steps:

[0053] S1. The worker fixes the support frame 20 of the flat gate valve to the designated installation position with anchor bolts to secure the flat gate valve.

[0054] S2. The worker connects the right connector 19 to the discharge port of the fracturing fluid pump (high pressure pump) and extends the pumping pipe of the high pressure pump into the fracturing fluid storage tank. Then, the worker connects the left connector 19 to the top port of the wellhead, thus completing the installation of the flat gate valve.

[0055] S3. Operation of pumping fracturing fluid into the shale gas layer: The worker starts the high-pressure pump, which extracts the fracturing fluid from the storage tank. The extracted fracturing fluid passes sequentially through the high-pressure pump, right connector 19, inlet 7, inner hole 8 of valve core 5, outlet 6, left connector 19, and wellhead, finally entering the shale gas layer. After a certain amount is pumped in, the piston rod of the control valve cylinder 3 retracts upward, and the piston rod drives the valve core 5 to move upward. The lower end of the valve core 5 cuts off the inlet 7 and outlet 6 to prevent the fracturing fluid in the wellhead from flowing back, thus realizing the pumping of fracturing fluid into the shale gas layer.

[0056] After the flat gate valve has been in operation for a period of time, a large amount of dirt will accumulate on the inner wall of the inner hole of the valve core 5. The specific steps for cleaning this dirt are as follows:

[0057] S1. The worker controls the piston rod of valve cylinder 3 to retract upwards. The piston rod drives valve core 5 to move upwards. When the piston rod is fully retracted, valve core 5 cuts off the liquid inlet 7 and the liquid outlet 6. Figure 7 As shown, the inner hole 8 of the valve core 5 is opposite to the nozzle 17 on the left and right, and the inner hole 8 of the valve core 5 is connected to the drain pipe 21.

[0058] S2. The worker controls the piston rod of the feed cylinder 14 to extend to the right. The piston rod drives the push plate 15 to move to the right. The push plate 15 drives the straight pipe 16 and the nozzle 17 to move to the right simultaneously. The nozzle 17 extends from left to right into the inner hole of the valve core 5. At the same time, the worker pumps cleaning fluid into the hose 24. Under the pump pressure, the cleaning fluid passes through the hose section 24, the straight pipe section 16, and the nozzle 17 in sequence, and finally sprays out from the spray hole 18. The spray direction is as follows: Figure 8 As shown by the middle arrow, the sprayed cleaning fluid is injected onto the inner wall of the inner hole 8. Figure 8 As shown, the dirt adhering to the inner wall of the inner hole 8 is flushed off. The flushed dirt, propelled by the cleaning fluid, is discharged outwards through the drain pipe 21. Once the conical nozzle 17 has completely passed through the inner hole 8, all the dirt on the inner wall of the valve core 5's inner hole 8 is removed, thus achieving the final cleaning of the dirt. In step S2, by controlling the nozzle 17 of the cleaning mechanism 13 to move to the right and pumping cleaning fluid into the nozzle 17, the cleaning fluid is sprayed out at an angle from the spray hole 18, thereby achieving automatic dirt cleaning. Compared to traditional disassembly-based cleaning, there is no need to disassemble and assemble the valve core 5; instead, dirt is cleaned online, greatly improving the cleaning efficiency. Furthermore, no manual cleaning is required; cleaning can be completed in a single operation, significantly reducing the workload of workers.

[0059] S3. After cleaning, stop pumping cleaning fluid into hose section 24, and then the worker controls the piston rod of feed cylinder 14 to retract, so that the flat gate valve can continue to be used.

[0060] When the valve core 5 of the flat gate valve is damaged in the closed state, the valve core 5 cuts off the inlet 7 and outlet 6. The steps for pumping fracturing fluid into the well are as follows: the operator controls the piston rod of the drive cylinder 25 to retract to the right, the piston rod drives the plug 23 to move to the right, and the plug 23 separates from the bypass section 11. Figure 9 As shown, the fracturing fluid sequentially flows through the high-pressure pump, right-side connector 19, inlet 7, bypass channel section 11, horizontal channel section 10, vertical channel section 9, outlet 6, left-side connector 19, and finally enters the wellhead to fracturing the shale gas layer. The flow direction of the fracturing fluid is as follows: Figure 9 As shown by the hollow arrow, fracturing fluid was delivered to fracturing shale gas reservoirs even when valve core 5 was damaged, ensuring the smooth delivery of fracturing fluid.

[0061] The detailed explanations of the above embodiments are intended only to explain the present invention so as to enable a better understanding of the present invention. However, these descriptions should not be construed as limiting the present invention for any reason. In particular, the various features described in different embodiments can be arbitrarily combined with each other to form other embodiments. Unless there is an explicit description to the contrary, these features should be understood to be applicable to any embodiment, and not limited to the described embodiments.

Claims

1. A flat gate valve for fracturing shale gas formations, characterized in that, The flat gate valve for shale gas fracturing includes: The valve body (1) has a main fluid channel and a guide groove (4) that are intersected and arranged inside. The main fluid channel passes through the valve body. One end of the guide groove (4) is open to the outer wall of the valve body (1), and the other end of the guide groove (4) is closed. The valve core (5) has a drive section, a connecting section and a closing section arranged in sequence. The connecting section has an inner hole that runs radially through the valve core (5). The valve core (5) passes through the guide groove (4) and is sealed and slidably fitted with the inner wall of the guide groove (4). The valve core (5) has an open position and a cleaning position. When the valve core (5) is in the open position, the connecting section is located at the intersection of the main fluid channel and the guide groove (4) and connects to the main fluid channel. When the valve core (5) is in the cleaning position, the connecting section moves to the outside of the valve body (1) and the closing section blocks the main fluid channel. The shale gas fracturing flat gate valve also includes a valve cylinder (3) for driving the valve core (5) to slide back and forth. The valve cylinder (3) is fixedly connected to the valve body (1) by a bracket (2), and the piston rod of the valve cylinder (3) is fixedly connected to the driving section of the valve core (5). The shale gas fracturing plate gate valve also includes a cleaning mechanism, which includes an infusion pipe, a spray pipe and a drain pipe (21). The infusion pipe and the drain pipe (21) are installed on the bracket (2) and located on both sides of the valve core (5). When the valve core (5) is in the cleaning position, the infusion pipe and the drain pipe (21) are aligned with the inner hole. The spray pipe is located at the end of the infusion pipe and can spray cleaning fluid into the inner hole. The valve body (1) is also provided with a flow guide channel. Both ends of the flow guide channel are connected to the main fluid channel and are located on opposite sides of the valve core (5). The flow guide channel and the guide groove (4) are not connected to each other. The valve body (1) is provided with a blocking mechanism (12) that can control the connection and disconnection of the flow channel; The blocking mechanism (12) includes a gantry (22), a drive cylinder (25), and a plug (23). An installation channel is also provided inside the valve body (1). One end of the installation channel is connected to the flow channel, and the other end of the installation channel opens into the outer wall of the valve body (1). The gantry (22) is fixed on the valve body (1) and aligns with the opening. The drive cylinder (25) is fixed on the gantry (22), and the piston rod of the drive cylinder (25) passes through the installation channel. The plug (23) is fixed at the end of the piston rod and slides in a sealed manner with the installation channel. The plug (23) can extend into the flow channel under the drive of the piston rod and isolate the flow channel.

2. The flat gate valve for shale gas fracturing as described in claim 1, characterized in that, The nozzle is a conical nozzle (17), and multiple injection holes are provided on the side wall of the conical nozzle (17).

3. The flat gate valve for shale gas fracturing as described in claim 2, characterized in that, Each of the injection holes is inclined toward the inner hole.

4. The flat gate valve for shale gas fracturing as described in claim 1, characterized in that, The cleaning mechanism also includes a feed cylinder (14) and a push plate (15). The feed cylinder (14) is fixedly connected to the bracket (2). The push plate (15) is fixedly connected to the piston rod of the feed cylinder (14). The infusion tube is fixedly connected to the push plate (15). The infusion tube can move toward the inner hole under the drive of the piston rod.

5. A method for operating a flat gate valve for fracturing shale gas formations, characterized in that, The shale gas fracturing plate gate valve as described in any one of claims 1 to 4 is installed at the wellhead. One end of the main fluid channel is connected to the wellhead, and the other end of the main fluid channel is connected to the fracturing fluid pump. The valve core (5) is in the open position, and the fracturing fluid pump delivers fracturing fluid to the wellhead through the main fluid channel. After delivering a predetermined amount of fracturing fluid, the valve core (5) is in the cleaning position and the inner hole of the valve core (5) is cleaned.

6. The operating method of the flat gate valve for shale gas fracturing as described in claim 5, characterized in that, Cleaning the valve core includes: Step 1: Control the valve core (5) to move upward, so that the inner hole of the valve core (5) is opposite to the nozzle on the left and right, and the inner hole of the valve core (5) is connected to the drain pipe (21); Step 2: Spray cleaning fluid into the inner hole through the nozzle. The cleaning fluid carries the dirt in the inner hole into the drain pipe (21). Step 3: After cleaning is completed, stop pumping cleaning fluid into the nozzle and allow the valve core (5) to move downwards back into the valve body (1).

7. The operating method of the flat gate valve for shale gas fracturing as described in claim 5, characterized in that, When the valve core (5) is damaged, the control blockage mechanism (12) keeps the flow channel connected, and the fracturing fluid flows to the wellhead through the high-pressure pump, the right connector (19), the inlet (7), the flow channel, the outlet (6), and the left connector (19).

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