Oil-rich coal in-situ pyrolysis and pressure slow-release extraction device and extraction method thereof

Abstract

The present application relates to a kind of rich oil coal in-situ pyrolysis and pressure release extraction device and extraction method, device includes: coil heating device, setting in injection well vertical hole;Downhole packer, setting in injection well horizontal hole, two downhole packers are fixedly connected by iron bar;Gas injection pressurizing device, setting on the ground at injection well mouth, its first output port is communicated with the gas inlet of coil heating device, the gas outlet of coil heating device is communicated with the pyrolysis zone between two downhole packers;Second output port is communicated with the inside of two downhole packers;Oil and gas collection assembly, setting on the ground at recovery well wellhead, including pumping unit, oil-gas separation device.The present application uses gas as heat carrier medium, efficiently transfers heat to underground coal seam, realizes uniform heating and sufficient pyrolysis of coal seam by sub-cycle stewing well pyrolysis, uses pressure release extraction technology, recovers pyrolysis product and gas, improves rich oil coal pyrolysis efficiency.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of in-situ pyrolysis of oil-rich coal, and particularly relates to an in-situ pyrolysis and pressure release extraction device for oil-rich coal and an extraction method thereof. BACKGROUND

[0002] China is rich in oil-rich coal resources, and the underground in-situ pyrolysis of "oil extraction and carbon retention" is the main trend of green and efficient development of oil-rich coal resources. However, traditional oil-rich coal mining and utilization methods, such as surface gasification and pyrolysis, have problems such as high cost, complex process and environmental pollution, which restrict the efficient development and utilization of oil-rich coal resources. In-situ pyrolysis technology, as a potential solution, directly processes coal seams underground, reducing the construction and operation costs of surface facilities and reducing environmental pollution. This technology uses a heat carrier to perform pyrolysis reactions in the underground coal seam, converting organic matter in the coal seam into gaseous or liquid products, thereby achieving efficient energy utilization. However, traditional coal gasification and pyrolysis technologies, while improving energy utilization efficiency, are often limited by uneven underground temperatures, difficult gas flow control, and low long-distance heat transfer efficiency. Especially in long-distance underground operations, how to effectively transfer heat and control gas flow has become a technical problem that needs to be solved. SUMMARY

[0003] In view of the deficiencies of the prior art, the present application provides an in-situ pyrolysis and pressure release extraction device for oil-rich coal and an extraction method thereof. This technology uses gas as a heat-carrying medium to efficiently transfer heat to the underground coal seam, and through segmented and cyclically stewing well pyrolysis, it realizes uniform heating and sufficient pyrolysis of the coal seam. At the same time, the pressure release extraction technology is used to effectively recover pyrolysis products and gas, thereby improving the pyrolysis efficiency of oil-rich coal.

[0004] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0005] An in-situ pyrolysis and pressure release extraction device for oil-rich coal, comprising:

[0006] A coil heating device is arranged in the vertical hole of the injection well for heating the heat-carrying gas to 600°C;

[0007] A downhole packer is arranged in the horizontal hole of the injection well and can move in a predetermined direction in the horizontal hole. Two downhole packers are arranged at intervals, and the two downhole packers can be tightly attached to the well wall when the gas injection reaches a certain pressure, so that a sealed environment is formed between the two packers to prevent heat leakage, and the two downhole packers are fixedly connected by an iron rod;

[0008] The gas injection and pressurization device is installed on the ground at the injection wellhead. Its first output port is connected to the air inlet of the coil heating device through the gas injection pipeline in the pyrolysis zone between the first packers. The air outlet of the coil heating device is connected to the pyrolysis zone between the two downhole packers through the gas injection pipeline in the pyrolysis zone between the second packers. The second output port of the gas injection and pressurization device is connected to the inside of the two downhole packers through the gas injection pipeline inside the packers.

[0009] An oil and gas collection assembly is installed on the ground at the wellhead of the production well. It includes a pumping unit and an oil and gas separation device connected to the pumping unit. The pumping unit collects the pyrolysis oil and gas products and transmits them to the oil and gas separation device for heat transfer gas separation.

[0010] Preferably, the coil heating device is provided with an isolation baffle to increase the flow path and residence time of the heat-carrying gas in the heating area, so that it can be fully heated to the target temperature. The isolation baffle is in the shape of an arc and is fixed on the inner wall of the coil heating device in an alternating manner.

[0011] Preferably, the coil heating device is provided with a coil mounting shaft, the outer surface of which is surrounded by a heating coil, and the isolation baffles are distributed around the heating coil to reduce heat loss.

[0012] Preferably, the downhole packer is provided with an inflatable mushroom made of a high-temperature resistant material that can deform and expand under high-pressure gas conditions. When the input gas generates high pressure, the packer fits tightly against the well wall, forming a sealed structure and preventing heat loss from the gas in the pyrolysis zone.

[0013] Preferably, the injection wellhead is also equipped with a lowering cable car, which is connected to the downhole packer via a cable and is used to lower and move the downhole packer to different pyrolysis zones.

[0014] Preferably, the first output port of the gas injection and pressurization device is provided with a first gas injection switch and a pressure monitoring component, and the second output port of the gas injection and pressurization device is provided with a second gas injection switch and a pressure monitoring component. The first gas injection switch and pressure monitoring component and the second gas injection switch and pressure monitoring component are used to control the gas supply of the gas injection and pressurization device and to detect the pipeline pressure.

[0015] Preferably, the movable end of the pumping unit is connected to a pumping ball, which is located inside the production well and connected to the input port of the oil and gas separation device to transport the collected oil and gas products to the oil and gas separation device.

[0016] A kind of rich oil coal in-situ pyrolysis and pressure release extraction device carries out the extraction method of rich oil coal in-situ pyrolysis and pressure release, the method comprises:

[0017] Step 1, by lowering cable car, downhole packer is lowered to the designated position, and by gas injection pressurizing device, gas is filled to the inflatable mushroom in downhole packer through the second output port, so that it is inflated and deformed, so that the downhole packer is closely attached to the well wall, and the heat loss of the gas in the pyrolysis region is prevented.

[0018] Step 2, the heat-carrying gas in the gas injection pressurizing device is input into the coil heating device through the pyrolysis zone gas injection pipeline between the first packer, the flow path and residence time of the heat-carrying gas in the heating region are increased by the isolation baffle in the coil heating device, to ensure that it can be fully heated, and the temperature of the heat-carrying gas is heated to a high temperature state by the heating coil in the coil heating device.

[0019] Step 3, the coil heating device delivers the heated heat-carrying gas to the pyrolysis region between the two downhole packers through the pyrolysis zone gas injection pipeline between the second packer through its gas outlet, so that the temperature and pressure inside the pyrolysis region continuously rise, the heat-carrying gas radiates heat to the coal seams on both sides, forming a stewing state, and the high-temperature gas makes the coal seam in the first coal seam pyrolysis region pyrolyze.

[0020] Step 4, after the coal seam in the first coal seam pyrolysis region is pyrolyzed, the downhole packer is depressurized by the gas injection pressurizing device and the second gas injection switch and pressure monitoring assembly, so that it is separated from the inner wall of the shaft.

[0021] Step 5, the downhole packer is moved to the first coal seam pyrolysis region by the lowering cable car on the ground through the cable, and the inflatable mushroom in the downhole packer is inflated again by the gas injection pressurizing device through the second output port, so that it is inflated and deformed, so that the downhole packer is closely attached to the well wall, and the heat loss of the gas in the pyrolysis region is prevented.

[0022] Step 6, repeat the operations of steps 2-4 to form a circulating stewing, until the pyrolysis of the whole coal seam is completed.

[0023] Step 7, the products after the coal seam pyrolysis are driven by the high-pressure gas to gather in the shaft and are transported to the production well, the oil and gas in the shaft are collected and the pressure is released by the pumping unit, and the pressure in the shaft is monitored in real time; and the collected oil and gas is delivered to the oil and gas separation device for separation, and the heat-carrying gas after separation can be injected into the underground again to realize the recycling of the heat-carrying medium.

[0024] The technical effects and advantages of the present application are:

[0025] The oil-rich coal in-situ pyrolysis and pressure release extraction device provided by the application significantly improves the pyrolysis efficiency and reduces energy consumption through the innovative design of the coil heating device, the downhole packer, and key parts such as the isolation baffle in the coil heating device and the inflatable mushroom in the downhole packer.

[0026] In particular, the use of the inflatable mushroom in the downhole packer in combination with the gas injection and pressurization device effectively solves the problem of heat leakage in traditional pyrolysis processes, enhancing the stability and safety of the overall system.

[0027] In addition, the application of the gas injection switch and pressure monitoring assembly enables precise control of the pyrolysis process, helping to improve the quality and yield of oil and gas products.

[0028] The device has broad prospects in coal resource development, effectively developing and utilizing deep underground oil-rich coal resources, reducing mining costs, and reducing environmental impact, providing new ideas and technical support for the sustainable development of fossil energy. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 is a schematic diagram of the overall structure of the application;

[0030] Figure 2 is a schematic diagram of the internal structure of the coil heating device of the application;

[0031] Figure 3 is a schematic diagram of the structure of the downhole packer in the uncharged state of the application;

[0032] Figure 4 is a schematic diagram of the structure of the downhole packer in the charged state of the application.

[0033] BRIEF DESCRIPTION OF DRAWINGS:

[0034] 1 - Lowering cable car; 2 - Gas injection and pressurization device; 3 - First gas injection switch and pressure monitoring assembly; 4 - Cable; 5 - Packer internal gas injection pipeline; 6 - Injection well; 7 - Second gas injection switch and pressure monitoring assembly; 8 - Coil heating device; 9 - First packer between pyrolysis zone gas injection pipeline; 10 - Second packer between pyrolysis zone gas injection pipeline; 11 - Downhole packer; 15 - Oil pumping ball; 16 - Oil pumping machine; 17 - Oil and gas separation device; 21 - Inflatable mushroom; 22 - Second output port; 81 - Isolation baffle; 82 - Heating coil. DETAILED DESCRIPTION

[0035] The following embodiments given in conjunction with the accompanying drawings further illustrate the application.

[0036] Reference Figures 1-2As shown, a device for in-situ pyrolysis of oil-rich coal and pressure relief extraction, comprising: a coil heating device 8 arranged in the vertical hole of the injection well 6, for heating the heat-carrying gas to high temperature.

[0037] Downhole packers 11 arranged in the horizontal hole of the injection well 6 and movable in the horizontal hole in a predetermined direction, two of the downhole packers 11 are arranged in a spaced manner, and the two downhole packers 11 can be kept in close contact with the well wall when the gas injection reaches a certain pressure, so that a sealed environment is formed between the two packers 11 to prevent heat leakage, and the two downhole packers 11 are fixedly connected by an iron rod.

[0038] Gas injection and pressure device 2 arranged on the ground surface of the injection well 6, the first output port 21 of the gas injection and pressure device 2 is connected with the gas inlet of the coil heating device 8 through the gas injection pipeline 9 between the first packers and the pyrolysis zone, and the gas outlet of the coil heating device 8 is connected with the pyrolysis zone between the two downhole packers 11 through the gas injection pipeline 10 between the second packers; the second output port 22 of the gas injection and pressure device 2 is connected with the inside of the two downhole packers 11 through the gas injection pipeline 5 inside the packers; the pipeline of the first output port 21 of the gas injection and pressure device 2 is provided with a first gas injection switch and a pressure monitoring component 3, and the pipeline of the second output port 22 of the gas injection and pressure device 2 is provided with a second gas injection switch and a pressure monitoring component 7, which are used to control the gas supply of the gas injection and pressure device 2 and detect the pressure in the pipeline.

[0039] For example, the gas injection switch of the present application can adopt a control valve, and the pressure monitoring component can adopt a pressure sensor. By using a control valve and a pressure sensor, the supply amount and pressure of high-pressure gas can be adjusted in real time, and the pressure change in the pipeline can be monitored in real time to prevent overpressure or underpressure.

[0040] The connection of the gas injection + pressure device 2 and the pyrolysis zone gas injection pipeline 9 between the first packers ensures the stable supply of heat-carrying gas, and the pressure monitoring device can monitor the internal pressure of the pipeline in real time to ensure the safety and controllability of the pyrolysis process. The gas injection and pressure device 2 delivers heat-carrying gas to the underground through the pyrolysis zone gas injection pipeline 9 between the first packers, and the pressure monitoring device monitors the pressure change during the gas delivery process to prevent overpressure or underpressure. Therefore, the safety and efficiency of the pyrolysis process can be ensured.

[0041] The oil and gas collection assembly is arranged on the ground of the wellhead of the production well, and comprises a pumping unit 16 and an oil and gas separation device 17 connected with the pumping unit 16, wherein the pumping unit 16 collects the pyrolysis oil and gas product and transmits the pyrolysis oil and gas product to the oil and gas separation device 17 for heat carrier gas separation.

[0042] The embodiment uniformly transmits heat to the coal seam in all directions through the horizontal hole of the injection well 6, and realizes the overall pyrolysis of the coal seam. The cooperation of the downhole packer 11 and the inflatable mushroom 21 can ensure the sealing of the pyrolysis area, reduce heat loss, and improve the pyrolysis efficiency. The segmented and cyclic stewing well pyrolysis makes the coal seam pyrolysis more uniform, and the pressure relief extraction technology effectively recovers the pyrolysis products and gas, and improves the utilization efficiency of oil-rich coal.

[0043] In one embodiment, the coil heating device 8 is provided with an isolation baffle 81 for increasing the flow path and residence time of the heat carrier gas in the heating area, so that the heat carrier gas can be fully heated to the target temperature. The isolation baffle 81 is in the form of an arch structure and is fixed on the inner wall of the coil heating device 8 in a staggered manner.

[0044] The coil heating device 8 is provided with a coil mounting shaft, and the outer surface of the coil mounting shaft is surrounded by a heating coil 82. The isolation baffle 81 is distributed around the heating coil 82 to reduce heat loss.

[0045] The application reduces heat loss by providing an isolation baffle 81 around the heating coil 82, which cooperates with the heating coil 82 to reduce heat loss. The design of the isolation baffle 81 can effectively reduce heat loss and improve heating efficiency. The isolation baffle 81 prevents heat around the heating assembly from dissipating to the external environment, so that the temperature of the heat carrier gas in the heating area can quickly reach the target temperature. Thus, the pyrolysis efficiency can be significantly improved, and the energy consumption can be reduced.

[0046] In one embodiment, the downhole packer 11 is provided with an inflatable mushroom 21, and the material of the inflatable mushroom 21 is a high-temperature-resistant material that can be deformed and expanded under high-pressure gas. After the input gas generates high pressure, the packer is tightly attached to the well wall to form a sealing structure, thereby preventing heat loss of the gas in the pyrolysis area.

[0047] By using a high-temperature-resistant material that can be deformed and expanded under high-pressure gas conditions for the inflatable mushroom 21, and matching it with a high-temperature movable sealing assembly, a sealing structure is formed. The selection and design of the high-temperature-resistant material ensure the stability and reliability of the sealing assembly in a high-temperature and high-pressure environment. The high-temperature-resistant material expands under the action of high-pressure gas, tightly adheres to the well wall, and forms an effective seal to prevent heat and gas leakage. This allows the downhole packer 11 to significantly improve the sealing effect of the pyrolysis region, reduce heat loss, and improve pyrolysis efficiency.

[0048] It should be noted that the inflatable mushroom 21 has a multi-layer structure design and is used in cooperation with the downhole packer 11 to adaptively seal with the hole diameter. The multi-layer structure design can adapt to changes in different hole diameters, ensuring good sealing effect in any situation. The multi-layer structure design of the inflatable mushroom 21 allows it to automatically adjust the sealing state under the action of high-pressure gas according to the hole diameter, ensuring the sealing of the pyrolysis region. This effectively prevents heat and gas leakage and improves pyrolysis efficiency.

[0049] Participation Figure 3 , Figure 4 As shown in the figure, when the inflatable mushroom 21 is not inflated, the downhole packer 11 is not sealed with the inner wall of the shaft. At this time, the downhole packer 11 can move inside the shaft. When the inflatable mushroom 21 is inflated, it expands under the action of high-pressure gas, causing the downhole packer 11 to tightly adhere to the inner wall of the shaft, forming an effective seal to prevent heat and gas leakage.

[0050] In one embodiment, the injection well 6 is also provided with a running cable 1 connected to the downhole packer 11 through a cable 4, which is used to lower and move the downhole packer 11 to different pyrolysis regions.

[0051] It should be noted that the contact surface between the downhole packer 11 and the well wall is lubricated during movement. Lubrication can reduce friction between the sealing assembly and the well wall, ensuring smoothness and stability during movement. By applying high-temperature-resistant lubricant to the contact surface between the high-temperature movable sealing assembly and the well wall, the moving resistance is reduced, and the sealing assembly is prevented from being damaged due to friction during movement. Lubrication can improve the service life of the high-temperature movable sealing assembly and reduce maintenance costs.

[0052] 7. The in-situ pyrolysis and pressure release extraction device for oil-rich coal according to claim 1, characterized in that the movable end of the pumping unit 16 is connected with a pumping ball 15, and the pumping ball 15 is located in the recovery well and communicates with the input port of the oil and gas separation device 17 to transport the collected oil and gas products into the oil and gas separation device 17.

[0053] The pyrolysis products are extracted in the production well by the pumping unit 16, and the pumping unit 16 is connected with the oil-gas separation device 17 to enhance the product transportation capacity. Through the design of the pumping unit 16 and the oil-gas separation device, the collection efficiency and purity of the pyrolysis products can be effectively improved, the pyrolysis products can be timely and safely transported to the ground, the oil-gas mixture can be separated by the oil-gas separation device 17, the recovery rate of the products is improved, and the collection efficiency and quality of the pyrolysis products are improved.

[0054] The application discloses a device and a method for in-situ pyrolysis of oil-rich coal and pressure release extraction.

[0055] Step 1: the downhole packer 11 is lowered to a designated position by the downhole cable car 1, and the inflatable mushroom 21 in the downhole packer 11 is inflated by the gas injection and pressurization device 2 through the second output port 22, so that the inflatable mushroom 21 is inflated and deformed, and the downhole packer 11 is tightly attached to the well wall, thereby preventing the heat loss of the gas in the pyrolysis area;

[0056] Step 2: the heat-carrying gas in the gas injection and pressurization device 2 is input into the coil heating device 8 through the pyrolysis area gas injection pipeline 9 between the first packers, the flow path and residence time of the heat-carrying gas in the heating area are increased by the isolation baffle 81 in the coil heating device 8, so that the heat-carrying gas can be fully heated, and the temperature of the heat-carrying gas is heated to a high-temperature state by the heating coil 82 in the coil heating device 8;

[0057] Step 3: the coil heating device 8 delivers the heated heat-carrying gas to the pyrolysis area between the two downhole packers 11 through the pyrolysis area gas injection pipeline 10 between the second packers through the gas outlet, so that the temperature and pressure in the pyrolysis area are continuously increased, the heat-carrying gas is radiated to the coal seams on both sides, and the state of stewing is formed; the high-temperature gas makes the coal seams in the first coal seam pyrolysis area pyrolyze;

[0058] Step 4: after the coal seams in the first coal seam pyrolysis area are pyrolyzed, the downhole packer 11 is depressurized by the gas injection and pressurization device 2 through the second gas injection switch and the pressure monitoring assembly 7, so that the downhole packer 11 is separated from the inner wall of the well;

[0059] Step 5: the downhole packer 11 is moved to the first coal seam pyrolysis area by the downhole cable car 1 on the ground through the cable 4, and the inflatable mushroom 21 in the downhole packer 11 is inflated again by the gas injection and pressurization device 2 through the second output port 22, so that the inflatable mushroom 21 is inflated and deformed, and the downhole packer 11 is tightly attached to the well wall, thereby preventing the heat loss of the gas in the pyrolysis area;

[0060] Step 6: the operations of steps 2-4 are repeated to form a cycle of stewing, and the whole coal seam is pyrolyzed until the pyrolysis is completed;

[0061] Step 7, the product after coal pyrolysis is driven by high pressure gas to gather in the shaft and is transported to the recovery well, the oil and gas in the shaft is collected and the pressure is released by the pumping unit 16, and the pressure in the shaft is monitored in real time; and the collected oil and gas is transported to the oil and gas separation device 17 for separation, and the heat carrying gas separated can be injected into the underground again to realize the recycling of the heat carrying medium.

[0062] The above only describes the preferred embodiments of the present application, and it should be noted that for those skilled in the art, without departing from the concept of the present application, several modifications and improvements can be made, which are all within the protection scope of the present application.

Claims

1. A device for in-situ pyrolysis and pressure-release extraction of oil-rich coal, characterized in that, The device includes: A coil heating device (8) is installed in the vertical hole of the injection well (6) for heating the heat carrier gas; Downhole packer (11) is installed in the horizontal hole of the injection well (6) and can move in a predetermined direction in the horizontal hole. There are two downhole packers (11), which are spaced apart. The two downhole packers (11) can be kept in close contact with the well wall when the gas injection reaches a certain pressure, so that a sealed environment is formed between the two packers (11) to prevent heat leakage. The two downhole packers (11) are fixedly connected by iron rods. The gas injection pressurization device (2) is installed on the ground at the injection well (6) opening. Its first output port (21) is connected to the air inlet of the coil heating device (8) through the gas injection pipe (9) between the first packers in the pyrolysis zone. The air outlet of the coil heating device (8) is connected to the pyrolysis zone between the two downhole packers (11) through the gas injection pipe (10) between the second packers in the pyrolysis zone. The second output port (22) of the gas injection pressurization device (2) is connected to the inside of the two downhole packers (11) through the gas injection pipe (5) inside the packer. The oil and gas collection assembly is set on the ground at the wellhead of the production well and includes a pumping unit (16) and an oil and gas separation device (17) connected to the pumping unit (16). The pumping unit (16) collects the pyrolysis oil and gas products and transmits them to the oil and gas separation device (17) for heat transfer gas separation.

2. The oil-rich coal in-situ pyrolysis and pressure-release extraction device according to claim 1, characterized in that: The coil heating device (8) is provided with an isolation baffle (81) to increase the flow path and residence time of the heat-carrying gas in the heating area, so that it can be fully heated to the target temperature. The isolation baffle (81) is in the shape of an arc and is fixed on the inner wall of the coil heating device (8) in an alternating manner.

3. The oil-rich coal in-situ pyrolysis and pressure-release extraction device according to claim 2, characterized in that: The coil heating device (8) is provided with a coil mounting shaft, and a heating coil (82) is surrounded on the outer surface of the coil mounting shaft. The isolation baffle (81) is distributed around the heating coil (82) to reduce heat loss.

4. The oil-rich coal in-situ pyrolysis and pressure-release extraction device according to claim 1, characterized in that: The downhole packer (11) is equipped with an inflatable mushroom (21) inside. The inflatable mushroom (21) is made of a high-temperature resistant material. It can deform and expand under high pressure gas conditions. After the input gas generates high pressure, the packer is tightly attached to the well wall to form a sealing structure and prevent the loss of gas heat in the pyrolysis zone.

5. The in-situ pyrolysis and pressure-release extraction device for oil-rich coal according to claim 1, characterized in that: The injection well (6) is also equipped with a lowering cable car (1), which is connected to the downhole packer (11) via a cable (4) for lowering and moving the downhole packer (11) to different pyrolysis zones.

6. The oil-rich coal in-situ pyrolysis and pressure-release extraction device according to claim 1, characterized in that: The first output port (21) of the gas injection and pressurization device (2) is provided with a first gas injection switch and pressure monitoring component (3), and the second output port (22) of the gas injection and pressurization device (2) is provided with a second gas injection switch and pressure monitoring component (7). The first gas injection switch and pressure monitoring component (3) and the second gas injection switch and pressure monitoring component (7) are used to control the gas supply of the gas injection and pressurization device (2) and to detect the pipeline pressure.

7. The in-situ pyrolysis and pressure-release extraction device for oil-rich coal according to claim 1, characterized in that: The pumping unit (16) is connected to a pumping ball (15) at its movable end. The pumping ball (15) is located in the production well and is connected to the input port of the oil and gas separator (17) to transport the collected oil and gas products into the oil and gas separator (17).

8. A method for extracting oil-rich coal through in-situ pyrolysis and pressure-release extraction using a device for in-situ pyrolysis and pressure-release extraction as described in any one of claims 1-7, characterized in that, The method includes: Step 1: The downhole packer (11) is lowered to the designated position by the lowering cable car (1), and the air-filled mushroom (21) inside the downhole packer (11) is inflated by the air-filling pressurizing device (2) through the second output port (22) to expand and deform, so that the downhole packer (11) fits tightly against the well wall and prevents the loss of gas heat in the pyrolysis zone; Step 2: The heat-carrying gas in the gas injection and pressurization device (2) is input into the coil heating device (8) through the gas injection pipe (9) in the pyrolysis zone between the first packers. The isolation baffle (81) in the coil heating device (8) increases the flow path and residence time of the heat-carrying gas in the heating zone to ensure that it can be fully heated. The temperature of the heat-carrying gas is heated to 600°C by the heating coil (82) in the coil heating device (8). Step 3: The coil heating device (8) delivers heated heat-carrying gas through its outlet to the pyrolysis zone gas injection pipe (10) between the two downhole packers (11) via the gas injection pipe (10) between the second packers. This causes the temperature and pressure inside the pyrolysis zone to rise continuously, causing the heat-carrying gas to dissipate heat to the upper and lower sides, forming a smoldering state. The high-temperature gas causes the coal seam in the first coal seam pyrolysis zone to pyrolyze. After the coal seam pyrolysis in the first coal seam pyrolysis area is completed in step 4, the downhole packer (11) is depressurized by the gas injection pressurization device (2) and the second gas injection switch and pressure monitoring component (7) so that it is separated from the inner wall of the well. Step 5: The packer (11) is moved to the second coal seam pyrolysis zone by the cable (4) via the cable car (1) on the ground. The packer (11) is then re-inflated by the gas injection pressurization device (2) through the second outlet (22) into the gas inflator (21) inside the packer (11), causing it to expand and deform, thereby making the packer (11) fit tightly against the well wall and preventing the loss of gas heat in the pyrolysis zone. Step 6: Repeat steps 2-4 to form a circulating well-steaming process until the pyrolysis of the entire coal seam is completed; Step 7: After the coal seam pyrolysis is completed, the products are accumulated inside the well under the drive of high pressure gas and transported to the production well. The oil and gas inside the well are collected and pressure is released by the pumping unit (16), and the pressure inside the well is monitored in real time. The collected oil and gas are transported to the oil and gas separation device (17) for separation. After the heat transfer gas is separated, it can be injected back into the ground to realize the recycling of the heat transfer medium.

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