Shale gas reservoir methane burning explosion fracturing structure

Abstract

The invention provides a shale gas reservoir methane burning explosion fracturing structure which comprises a stabilizing assembly, a conveying assembly and a packing assembly, the stabilizing assembly is composed of a shaft sleeve, a bottom packer and a top packer are fixedly installed in the two ends of the shaft sleeve respectively, and the conveying assembly is composed of an oil pumping pipe column. A jet flow mechanism is fixedly installed in the oil pumping pipe column, the packing assembly is fixedly installed on the inner wall of a shaft sleeve, and a guide column is arranged in the packing assembly. Fuel and combustion improver conveying is achieved through the oil pumping pipe column in the shaft sleeve, fuel filling is achieved through the conveying assembly in the oil pumping pipe column, high-pressure gas conveying is achieved through cooperation of the sand blasting pipe and the gas inlet pipe, and solid fuel storage is achieved through cooperation with fractured gaps; the sequential conveying of the fuel and the combustion improver is realized through the packing assembly, the automatic opening of the packing assembly is realized by utilizing the air pressure generated during conveying, the mixing of the sequentially conveyed gases can be realized underground, and the safety performance of the burning and explosion operation can also be improved.

Description

Technical Field

[0001] The present invention relates to a methane combustion explosion fracturing structure for shale gas reservoirs, belonging to the technical field of shale gas reservoir exploitation. Background Art

[0002] Methane combustion explosion fracturing of shale gas reservoirs is an innovative shale gas exploitation technology. Shale gas is usually stored in gas-producing rocks such as dark shale and high-carbon shale in adsorbed and free states, and is a clean and efficient energy resource. However, compared with conventional natural gas reservoirs, shale gas reservoirs generally have the characteristics of low porosity and low permeability, which makes their exploitation difficult. In order to improve the recovery rate of shale gas, fracturing technology has been widely used in the development of shale gas reservoirs. Although the traditional hydraulic fracturing technology can form relatively long fractures, the expansion form and direction of the fractures are relatively limited, and there are risks such as large water resource consumption and environmental pollution. Therefore, it is particularly important to develop a new and more efficient fracturing technology. The methane combustion explosion fracturing technology for shale reservoirs utilizes the methane gas desorbed in-situ from the shale gas reservoir and the injected combustion promoter (such as oxygen, etc.) to synergistically combust and explode, generating high-temperature and high-pressure gas to impact and fracture the shale reservoir. Through the combustion explosion reaction of methane, high-temperature and high-pressure shock waves and explosion-generated gases are generated in a very short time. These energies act on the shale reservoir, causing it to generate fractures and expand, thereby constructing a complex fracture network and providing an efficient migration channel for shale gas.

[0003] As a new type of waterless fracturing technology, the methane combustion explosion fracturing technology has broad application prospects in the field of shale gas exploitation. With the continuous development and improvement of the technology, it is expected to become one of the mainstream technologies for future shale gas exploitation, contributing to China's energy security and sustainable development. The methane combustion explosion fracturing technology can form a complex and efficient fracture network, increase the migration channels of shale gas, and thus improve the recovery rate. This technology does not require a large amount of fracturing fluid, avoiding the problems of large water resource consumption and environmental pollution. At the same time, since it does not involve the above-ground transportation and mixing processes of explosive materials, it also reduces the safety risks. The methane combustion explosion fracturing technology is applicable to different types of shale reservoirs, including reservoirs such as deep coalbed methane that are difficult to fracture with traditional hydraulic fracturing technology.

[0004] Methane combustion explosion fracturing of shale gas reservoirs is an innovative and forward-looking shale gas exploitation technology that realizes combustion explosion fracturing by using the methane gas in the reservoir and the supplied combustion promoter. In the actual production process, due to the relatively small gap of the fractures generated by the previous fracturing, it may be difficult to achieve the fracturing effect with a fixed amount of methane gas, especially when the fuel cannot effectively fill the fractures, resulting in a reduction in the subsequent fracturing effect. Moreover, during the transportation of methane gas and the combustion promoter, due to the existence of the wellhead mixing and transportation process, there are easily potential safety hazards in the actual production process, and it is not easy to achieve effective mixing after the injection is completed, affecting the combustion explosion fracturing efficiency. Summary of the Invention

[0005] The present invention provides a methane combustion explosion fracturing structure for shale gas reservoirs to solve the technical problems of poor fracturing effect of combustion explosion and low transportation safety.

[0006] The present invention solves the above technical problems through the following technical solutions: The present invention provides a methane combustion explosion fracturing structure for shale gas reservoirs, and the methane combustion explosion fracturing structure for shale gas reservoirs includes: A stabilizing component, which is composed of a wellbore casing. The wellbore casing is arranged inside a vertical shaft opened in a shale layer. Bottom packers and top packers are fixedly installed inside both ends of the wellbore casing respectively. A conveying component, which is arranged inside the wellbore casing. The conveying component is composed of a tubing string. A jetting mechanism is fixedly installed inside the tubing string. A terminal pipe is fixedly installed at the bottom of the tubing string, and the jetting mechanism extends into the terminal pipe. A packing component, which is fixedly installed on the inner wall of the wellbore casing. A number of uniformly distributed guide columns are arranged inside the packing component. The packing component is arranged between the top packer and the bottom packer.

[0007] In this technical solution, the number of the wellbore casings is several and they are uniformly distributed and embedded inside the shale layer. A number of vertical shafts are arranged inside the shale layer, and the vertical shafts extend into the shale gas reservoir. An ignition switch is fixedly installed inside the wellbore casing, and the ignition switch is located above the bottom packer.

[0008] In this technical solution, the bottom packer is arranged at the bottom of the vertical shaft. The top packer is located inside the wellbore casing at the top of the vertical shaft. The number of the top packers is two, and the two top packers are sequentially distributed on the inner wall of the wellbore casing. A pressure sensor is arranged between the two top packers, and the pressure sensor is uniformly arranged between the two top packers.

[0009] In this technical solution, a number of uniformly distributed openings are formed on the surface of the wellbore casing. The openings are correspondingly distributed with the conveying component. Fracture gaps are formed inside the shale layer on one side of the openings, and the fracture gaps are uniformly distributed at an inclined downward angle into the shale gas reservoir.

[0010] In this technical solution, the surface of the tubing string is fixedly connected with the top packer and the packing component respectively. Two internal packers are fixedly connected inside the tubing string. One of the internal packers is arranged at the top of the tubing string. A connecting pipe is fixedly connected to the tubing string above the other internal packer. The connecting pipe is arranged between the two internal packers. The connecting pipe is correspondingly arranged above the packing component, and the end of the connecting pipe is fixedly connected with a valve.

[0011] In the technical solution, the diameter of the end pipe is larger than the diameter of the pumping pipe string, and a plurality of evenly distributed circular holes are opened on the surface of the end pipe, and the circular holes are located above the jet mechanism.

[0012] In the present technical solution, the jet mechanism is composed of an air intake pipe and a sandblasting pipe. The air intake pipe is fixedly connected to the inner wall of the pumping pipe column. The air intake pipe extends to the inside of the end pipe and is fixedly connected to the inner wall of the end pipe. The sandblasting pipe is arranged in the middle of the pumping pipe column, and the bottom end of the sandblasting pipe is connected to the air intake pipe through a plurality of branch pipes. The bottom of the air intake pipe is a bent structure and is connected to the bottom of the end pipe.

[0013] In the present technical solution, the number of the air inlet pipes is several, and the several air inlet pipes are fixedly connected to the edge of the internal packer. The middle part of the internal packer is fixedly connected to the sandblasting pipe. The bottom of the sandblasting pipe is a bent structure. The outer surface of the end pipe is fixedly installed with several evenly distributed boosting nozzles. Each boosting nozzle is an inclined structure and is connected to the inside of the end pipe, and the boosting nozzle is connected to one end of the air inlet pipe.

[0014] In the present technical solution, the isolation assembly is composed of a middle isolation packer, which is fixedly installed inside the wellbore casing. The middle isolation packer is located in the middle of the wellbore casing and is fixedly connected to the surface of the pumping pipe. The middle isolation packer is an annular structure, and the inside of the middle isolation packer is penetrated and plugged with a plurality of guide columns.

[0015] In the present technical solution, the guide column is a cylindrical structure, the bottom end of the guide column is fixedly connected to a fixed shaft, the top edge of the fixed shaft is fixedly connected to the sealing ring, and the sealing ring is fitted and connected to the bottom surface of the middle packer, a movable shaft is sleeved on the surface of the guide column located at the top of the middle packer, a notch is provided on the surface of the guide column above the movable shaft, the top surface of the middle packer is rotatably connected to the clamping rod, the clamping rod is a bent structure and is engaged and engaged with the inside of the notch, and the bent position of the clamping rod is in contact with the top edge of the movable shaft.

[0016] On the basis of being in accordance with the common sense in the art, the above-mentioned preferred conditions can be arbitrarily combined to obtain the preferred embodiments of the present invention.

[0017] The positive and progressive effects of the present invention are: The above-mentioned methane combustion and explosion fracturing structure for shale gas reservoirs uses a tubing string inside the wellbore casing to transport fuel and combustion promoter, and uses the transport components in the tubing string to fill the fuel. It can transport high-pressure gas through the cooperation of a sandblasting pipe and an intake pipe, can fill and compact the original fractures, and cooperate with the fractures formed by fracturing to store solid fuel, solving the problem of low fuel reserves in the fractures and providing a basis for subsequent efficient combustion and explosion. The fuel and combustion promoter are transported sequentially through a packer assembly, and the automatic opening of the packer assembly is achieved by using the air pressure generated during the transportation process. Gas mixing after sequential transportation can be realized underground, avoiding potential safety hazards that may occur during transportation on the ground. When ignited, the fuel and methane gas can combust and explode in the well, ensuring the fracturing effect and improving the safety performance of the combustion and explosion operation. Description of the Drawings

[0018] Figure 1 Schematic diagram of the overall three-dimensional structure of the present invention.

[0019] Figure 2 Schematic diagram of the three-dimensional structure at the wellbore casing of the present invention.

[0020] Figure 3 Schematic diagram of the internal front view structure at the wellbore casing of the present invention.

[0021] Figure 4 For the present invention Figure 3 Schematic diagram of the enlarged partial structure at position A.

[0022] Figure 5 Schematic diagram of the semi-sectional three-dimensional structure of the present invention.

[0023] Figure 6 Schematic diagram of the internal three-dimensional structure of the tubing string of the present invention.

[0024] Figure 7 Schematic diagram of the three-dimensional structure at the transport component of the present invention.

[0025] Figure 8 For the present invention Figure 7 Schematic diagram of the enlarged partial structure at position B.

[0026] Figure 9 Schematic diagram of the internal structure at the middle packer of the present invention.

[0027] Figure 10 Schematic diagram of the front view structure at the wellbore casing of the present invention.

[0028] Description of the Reference Numerals 100, stabilizing assembly; 101, wellbore casing; 102, bottom packer; 103, ignition switch; 104, top packer; 105, pressure sensor; 106, opening; 107, shale layer; 108, vertical shaft; 109, fracturing crack; 200, Delivery assembly; 201, Production tubing string; 202, Inner packer; 203, Connecting pipe; 204, End pipe; 205, Round hole; 206, Intake pipe; 207, Sandblasting pipe; 208, Boosting nozzle; 300, Packing assembly; 301, Middle packer; 302, Guide post; 303, Fixed shaft; 304, Sealing ring; 305, Movable shaft; 306, Locking bar. Specific implementation mode

[0029] The present invention will be further described below by way of embodiments, but the present invention is not limited to the scope of the described embodiments.

[0030] As Figure 1-10 shown, the methane combustion explosion fracturing structure of the shale gas reservoir includes: A stabilizing assembly 100, the stabilizing assembly 100 is composed of a wellbore casing 101, the wellbore casing 101 is arranged inside a vertical shaft 108 opened in a shale layer 107, and a bottom packer 102 and a top packer 104 are respectively fixedly installed inside both ends of the wellbore casing 101; A delivery assembly 200, the delivery assembly 200 is arranged inside the wellbore casing 101, the delivery assembly 200 is composed of a production tubing string 201, a jetting mechanism is fixedly installed inside the production tubing string 201, an end pipe 204 is fixedly installed at the bottom of the production tubing string 201, and the jetting mechanism extends into the end pipe 204; A packing assembly 300, the packing assembly 300 is fixedly installed on the inner wall of the wellbore casing 101, a plurality of uniformly distributed guide posts 302 are arranged inside the packing assembly 300, and the packing assembly 300 is arranged between the top packer 104 and the bottom packer 102.

[0031] The number of the wellbore casings 101 is several and they are evenly distributed and embedded inside the shale layer 107. A plurality of vertical shafts 108 are arranged inside the shale layer 107, and the vertical shafts 108 extend into the shale gas reservoir. An ignition switch 103 is fixedly installed inside the wellbore casing 101, and the ignition switch 103 is located above the bottom packer 102; the bottom packer 102 is arranged at the bottom of the vertical shaft 108, the top packer 104 is located inside the wellbore casing 101 at the top of the vertical shaft 108, the number of the top packers 104 is two, the two top packers 104 are sequentially distributed on the inner wall of the wellbore casing 101, and a pressure sensor 105 is arranged between the two top packers 104, and the pressure sensor 105 is evenly arranged between the two top packers 104.

[0032] In this technical solution, a plurality of vertical shafts 108 are arranged in the shale gas reservoir, and wellbore casings 101 are installed in the vertical shafts 108. Fracture cracks 109 are pre-fractured in the shale gas reservoir. After solid fuel and a combustion promoter are filled inside the wellbore casings 101, ignition is achieved through an ignition switch 103. The generated combustion and explosion gas is blocked by a bottom packer 102 and a top packer 104, so that the generated high-pressure gas further extends the fracture cracks 109. By setting two top packers 104, the sealing performance is ensured, and a pressure sensor 105 is arranged therebetween to monitor the pressure during the combustion and explosion process, ensuring the safety performance during the combustion and explosion process.

[0033] A number of uniformly distributed openings 106 are formed on the surface of the wellbore casing 101. The openings 106 are correspondingly distributed with a conveying assembly 200. Fracture cracks 109 are formed inside a shale layer 107 on one side of the opening 106, and the fracture cracks 109 are uniformly distributed at an inclined downward angle into the shale gas reservoir; the surface of the tubing string 201 is fixedly connected to the top packer 104 and a packing assembly 300 respectively. Two internal packers 202 are fixedly connected inside the tubing string 201. One of the internal packers 202 is arranged at the top of the tubing string 201. A connecting pipe 203 is fixedly connected to the tubing string 201 above the other internal packer 202. The connecting pipe 203 is arranged between the two internal packers 202. The connecting pipe 203 is correspondingly arranged above the packing assembly 300, and the end of the connecting pipe 203 is fixedly connected to a valve.

[0034] In this technical solution, the openings 106 can be used for gas transportation. After the fracture cracks 109 are pre-fractured, the directions of the fracture cracks 109 are inconsistent at this time. High-pressure gas is first transported to the openings 106 through an inlet pipe 206. At the same time, a sandblasting pipe 207 transports sand and gravel into the inlet pipe 206. The air flow generated by the inlet pipe 206 enables the sand and gravel to enter a boosting nozzle 208 at high speed. The air flow ejected from the boosting nozzle 208 enters the fracture cracks 109, realizing the expansion of the fracture cracks 109. The inclined angle of the boosting nozzle 208 makes the inclined angle of the fracture cracks 109 downward, providing a storage space for subsequent fuel filling.

[0035] The diameter of the end pipe 204 is larger than the diameter of the pumping pipe string 201, and a plurality of evenly distributed circular holes 205 are opened on the surface of the end pipe 204, and the circular holes 205 are located above the jet mechanism; the jet mechanism is composed of an air intake pipe 206 and a sandblasting pipe 207, the air intake pipe 206 is fixedly connected to the inner wall of the pumping pipe string 201, the air intake pipe 206 extends to the inside of the end pipe 204 and is fixedly connected to the inner wall of the end pipe 204, the sandblasting pipe 207 is arranged in the middle of the pumping pipe string 201, and the bottom end of the sandblasting pipe 207 is connected to the air intake pipe 206 through a plurality of branch pipes, The bottom of the air inlet pipe 206 is a bent structure and is connected to the bottom of the end pipe 204; the number of the air inlet pipes 206 is several, and several air inlet pipes 206 are fixedly connected to the edge of the internal packer 202. The middle of the internal packer 202 is fixedly connected to the sandblasting pipe 207, and the bottom of the sandblasting pipe 207 is a bent structure. A plurality of evenly distributed boosting nozzles 208 are fixedly installed on the outer surface of the end pipe 204, and each boosting nozzle 208 is an inclined structure and is connected to the inside of the end pipe 204, and the boosting nozzle 208 is connected to one end of the air inlet pipe 206.

[0036] In the present technical solution, after the expansion of the fracture gap 109 is completed, the internal seal 202 is closed, and the gas fuel is transported by the air inlet pipe 206. At the same time, the solid fuel is transported to the inside of the booster nozzle 208 through the sandblasting tube 207. The high-speed flowing solid fuel is transported to the fracture gap 109 through the booster nozzle 208. At this time, the filling content of the solid fuel can be increased, so that more fuel can be stored in the fracture gap 109, ensuring the subsequent combustion and explosion effect.

[0037] The packing assembly 300 is composed of a middle packer 301, which is fixedly installed inside the wellbore casing 101. The middle packer 301 is located in the middle of the wellbore casing 101 and is fixedly connected to the surface of the pumping pipe string 201. The middle packer 301 is an annular structure, and the middle packer 301 is inserted through a plurality of guide columns 302; the guide column 302 is a cylindrical structure, and a fixed shaft 303 is fixedly connected to the bottom end of the guide column 302. The fixed shaft 303 The top edge is fixedly connected to the sealing ring 304, and the sealing ring 304 is fitted and connected to the bottom surface of the middle packer 301. The surface of the guide column 302 located at the top of the middle packer 301 is sleeved with a movable shaft 305, and a notch is opened on the surface of the guide column 302 located above the movable shaft 305. The top surface of the middle packer 301 is rotatably connected to the clamping rod 306. The clamping rod 306 is a bent structure and is engaged with the inside of the notch, and the bent position of the clamping rod 306 is in contact with the top edge of the movable shaft 305.

[0038] In this technical solution, after the fuel is transported into the inside of the wellbore casing 101 by the intake pipe 206 and the sandblasting pipe 207, the pressure inside the wellbore casing 101 increases due to the filling of high-pressure gas. At this time, the seal ring 304 at the fixed shaft 303 deforms and forces the guide post 302 and the fixed shaft 303 to move upward. During the upward movement of the guide post 302, the sealing performance at the connection is always ensured. When the guide post 302 moves upward, it separates from the latch rod 306. At this time, the air pressure at the bottom of the wellbore casing 101 keeps the guide post 302 in its original state. After closing the intake pipe 206 and the sandblasting pipe 207, the lower internal packer 202 is closed and the valve on the connecting pipe 203 is opened, and the combustion promoter is transported from the tubing string 201. The combustion promoter is transported through the connecting pipe 203 between the wellbore casing 101 and the tubing string 201. When the injected amount of the combustion promoter increases, the generated air pressure balances with the air pressure at the bottom. When the air pressures are the same, the guide post 302 falls due to its own weight, and the latch rod 306 will not return to its original state after being opened, so that the guide post 302 disengages from the inside of the movable shaft 305. After the guide post 302 is opened, the combustion promoter and the fuel on the upper and lower sides of the middle packer 301 are mixed.

[0039] Further, the combustion promoter is mainly oxygen, and the gaseous fuel can be methane gas. Since the density of methane gas is lower than that of oxygen, after the middle packer 301 is opened, the methane gas is mixed with the combustion promoter. After the mixing is completed, by starting the ignition switch 103, the fuel is combusted and exploded inside the wellbore casing 101. At this time, the burning gas ignites the solid fuel in the fracture 109, and the large amount of gas generated forces the fracture 109 to further expand and extend, thereby ensuring the effect of the combustion explosion fracturing of the shale gas reservoir. Moreover, the air pressure is used to mix the combustion promoter and the fuel in the vertical shaft 108, avoiding the potential safety accidents that may occur when mixing the fuel and the combustion promoter on the ground, improving the safety of the combustion explosion construction, and using the fuel filled in the fracture 109 to perform further fracturing operations to improve the combustion explosion effect.

[0040] The present invention is not limited to the above embodiments. No matter what changes are made in its shape or structure, they all fall within the protection scope of the present invention. The protection scope of the present invention is defined by the appended claims. Those skilled in the art can make various changes or modifications to these embodiments without departing from the principle and essence of the present invention, but these changes and modifications all fall within the protection scope of the present invention.

Claims

1. Methane combustion explosion fracturing structure for shale gas reservoir, characterized in that, The methane combustion and explosion fracturing structure of the shale gas reservoir includes: A stabilizing component (100), which is composed of a wellbore casing (101). The wellbore casing (101) is arranged inside a vertical shaft (108) opened in a shale layer (107). Bottom packers (102) and top packers (104) are fixedly installed inside both ends of the wellbore casing (101) respectively. A conveying component (200), which is arranged inside the wellbore casing (101). The conveying component (200) is composed of a tubing string (201). A jet mechanism is fixedly installed inside the tubing string (201). A terminal pipe (204) is fixedly installed at the bottom of the tubing string (201), and the jet mechanism extends into the terminal pipe (204). A packing component (300), which is fixedly installed on the inner wall of the wellbore casing (101). A number of uniformly distributed guide columns (302) are arranged inside the packing component (300). The packing component (300) is arranged between the top packer (104) and the bottom packer (102).

2. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 1, characterized in that: The number of the wellbore casings (101) is several and they are evenly distributed and embedded inside the shale layer (107). A number of vertical shafts (108) are arranged inside the shale layer (107), and the vertical shafts (108) extend into the shale gas reservoir. An ignition switch (103) is fixedly installed inside the wellbore casing (101), and the ignition switch (103) is located above the bottom packer (102).

3. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 2, wherein: The bottom packer (102) is arranged at the bottom of the vertical shaft (108). The top packer (104) is located inside the wellbore casing (101) at the top of the vertical shaft (108). The number of the top packers (104) is two, and the two top packers (104) are sequentially distributed on the inner wall of the wellbore casing (101). A pressure sensor (105) is arranged between the two top packers (104), and the pressure sensor (105) is evenly arranged between the two top packers (104).

4. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 1, characterized in that: A number of uniformly distributed openings (106) are formed on the surface of the wellbore casing (101). The openings (106) are correspondingly distributed with the conveying component (200). Fracture gaps (109) are formed inside the shale layer (107) on one side of the openings (106), and the fracture gaps (109) are uniformly distributed at an inclined downward angle into the shale gas reservoir.

5. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 1, characterized in that: The surface of the tubing string (201) is fixedly connected with the top packer (104) and the packing component (300) respectively. Two internal packers (202) are fixedly connected inside the tubing string (201). One of the internal packers (202) is arranged at the top of the tubing string (201). A connecting pipe (203) is fixedly connected to the tubing string (201) above the other internal packer (202). The connecting pipe (203) is arranged between the two internal packers (202). The connecting pipe (203) is correspondingly arranged above the packing component (300), and the end of the connecting pipe (203) is fixedly connected with a valve.

6. The methane combustion explosion fracturing structure for shale gas reservoirs according to claim 1, characterized in that: The diameter of the end pipe (204) is greater than the diameter of the pumping pipe string (201), and a plurality of evenly distributed circular holes (205) are opened on the surface of the end pipe (204), and the circular holes (205) are located above the jet mechanism.

7. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 1, characterized in that: The jet mechanism is composed of an air intake pipe (206) and a sandblasting pipe (207); the air intake pipe (206) is fixedly connected to the inner wall of the pumping pipe string (201); the air intake pipe (206) extends to the inside of the end pipe (204) and is fixedly connected to the inner wall of the end pipe (204); the sandblasting pipe (207) is arranged in the middle of the pumping pipe string (201); and the bottom end of the sandblasting pipe (207) is connected to the air intake pipe (206) through a plurality of branch pipes; the bottom of the air intake pipe (206) is a bent structure and is connected to the bottom of the end pipe (204).

8. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 7, wherein: The number of the air inlet pipes (206) is several, and the several air inlet pipes (206) are fixedly connected to the edge of the internal packer (202). The middle of the internal packer (202) is fixedly connected to the sandblasting pipe (207), and the bottom of the sandblasting pipe (207) is a bent structure. The outer surface of the end pipe (204) is fixedly installed with several evenly distributed boosting nozzles (208), each of which is an inclined structure and is connected to the inside of the end pipe (204), and the boosting nozzle (208) is connected to one end of the air inlet pipe (206).

9. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 1, characterized in that: The isolation assembly (300) is composed of a middle isolation packer (301), which is fixedly installed inside the wellbore casing (101). The middle isolation packer (301) is located in the middle of the wellbore casing (101) and is fixedly connected to the surface of the pumping pipe (201). The middle isolation packer (301) is an annular structure, and a plurality of guide columns (302) are inserted and penetrated inside the middle isolation packer (301).

10. The methane combustion explosion fracturing structure for shale gas reservoir according to claim 9, wherein: The guide column (302) is a cylindrical structure. The bottom end of the guide column (302) is fixedly connected to a fixed shaft (303). The top edge of the fixed shaft (303) is fixedly connected to a sealing ring (304). The sealing ring (304) is fitted and connected to the bottom surface of the middle packer (301). The surface of the guide column (302) located at the top of the middle packer (301) is sleeved with a movable shaft (305). A notch is provided on the surface of the guide column (302) located above the movable shaft (305). The top surface of the middle packer (301) is rotatably connected to a clamping rod (306). The clamping rod (306) is a bent structure and is engaged with the inside of the notch. The bent position of the clamping rod (306) contacts the top edge of the movable shaft (305).

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