A system and method for in-situ supercritical CO2 pyrolysis of oil-rich coal over a wide depth range

Abstract

The present invention discloses a system and method for in-situ pyrolysis of oil-rich coal in a wide depth range using supercritical CO2. Injection wells, first horizontal wells, second horizontal wells, and production wells are respectively opened in shallow oil-rich coal and deep oil-rich coal, and are supplemented by temperature monitors. In-situ pyrolysis of the oil-rich coal is achieved by injecting supercritical CO2, and the pyrolysis products are graded. At the same time, different plots are jointly operated, and the waste heat of the previous plot is used for the pyrolysis reaction of the next plot. CO2 is the heat carrier, and part of the CO2 is sealed in the previous plot. The entire process realizes the in-situ pyrolysis of oil-rich coal seams within different burial depths and thicknesses, fully utilizes the heat of the pyrolysis process, avoids heat waste, and the promoting effect of supercritical CO2 on heat and mass transfer improves the mining utilization rate of the oil-rich coal; at the same time, CO2 emissions are reduced, which helps promote the strategic goal of carbon neutrality.

Description

Technical Field

[0001] The present invention relates to a system and method for pyrolyzing oil-rich coal, and in particular to a system and method for in-situ pyrolysis of oil-rich coal over a wide depth range using supercritical CO2. Background Art

[0002] Utilizing coal-to-liquids technology is a reliable approach to increasing oil and gas production. Oil-rich coal is a type of coal with a tar content of 7-12%. The abundant reserves of oil-rich coal in western my country constitute a potential oil and gas resource. However, the environmental pollution and casualties caused by traditional coal mining and utilization processes cannot be ignored. In light of this, the new concept of in-situ pyrolysis of oil-rich coal has been proposed in recent years. This involves heating the oil-rich coal directly underground, pyrolyzing it to generate oil and gas products that are then extracted to the surface. This technology not only effectively avoids the pollution emissions and casualties associated with mining and coal combustion, but also increases the independent supply of oil and gas resources, which is of great strategic significance.

[0003] Convection heating is a common in-situ heating method. Currently, high-temperature fluids are mostly used to heat and pyrolyze coal seams under certain burial conditions. However, the burial conditions of coal seams at different locations are not the same, and there are significant differences in the in-situ pyrolysis conditions between shallow coal and deep coal. At the same time, the in-situ heating performance of traditional fluid media needs to be improved. Supercritical CO2 is a special fluid with high diffusivity and low viscosity. Using supercritical CO2 to convectively heat oil-rich coal helps to enhance heat and mass transfer during the in-situ pyrolysis of oil-rich coal. In addition, by adjusting the inlet parameters of supercritical CO2, in-situ pyrolysis of oil-rich coal seams within different burial depths and thickness ranges can be achieved. Therefore, the development of a system and method for in-situ pyrolysis of oil-rich coal over a wide depth range using supercritical CO2 is of great practical significance. Summary of the Invention

[0004] The object of the present invention is to provide a system and method for in-situ pyrolysis of oil-rich coal over a wide depth range using supercritical CO2.

[0005] To achieve the above objectives, the system of the present invention includes several progressively connected plots of land, each plot consisting of shallow oil-rich coal and deep oil-rich coal below the rock layer. Several injection wells and production wells are vertically excavated in the shallow oil-rich coal and deep oil-rich coal. Several first horizontal wells and several second horizontal wells perpendicular to the first horizontal wells are excavated in parallel above the shallow oil-rich coal and deep oil-rich coal at the bottoms of the injection wells and production wells. The combination of the injection wells, production wells, first horizontal wells, and second horizontal wells forms a fluid heating channel for in-situ pyrolysis of the oil-rich coal. Several temperature detectors are placed in the horizontal wells for real-time monitoring of the pyrolysis reaction temperature.

[0006] The injection well is connected to a supercritical CO2 generator for preparing supercritical CO2 fluids of different temperatures and pressures. The pyrolysis gas products enter the heat exchanger and the gas-liquid separation device in sequence through the production well. The coal tar obtained by condensation is collected in the oil storage device. The gas is separated into pyrolysis gas and CO2 through the CO2 capture device. The pyrolysis gas products are collected in the gas storage device. Part of the CO2 separated by the CO2 capture device is injected into the upper-level block through the injection well of the upper-level block to absorb the residual heat of pyrolysis. The preheated CO2 flows out of the production well and enters the supercritical CO2 generator of the next-level block. The other part of the CO2 separated by the CO2 capture device is injected into the semi-coke layer formed by pyrolysis of the upper-level block through the injection well of the upper-level block.

[0007] The injection well is also connected to a fracturing fluid pipeline for conveying fracturing fluid. The fracturing fluid is injected into the coal seam to form artificial fracturing cracks. The artificial cracks at different locations and the natural cracks in the coal seam together form an oil-rich coal seam crack network.

[0008] The fracturing fluid contains Fe, Co and Ni metal components.

[0009] The initial pressure of the supercritical CO2 fluid is greater than the coal seam reservoir pressure.

[0010] The first horizontal well and the second horizontal well are arranged vertically and crosswise on the horizontal plane.

[0011] The wellhead of the production well is provided with a temperature monitor for real-time control of the condensation degree of the pyrolysis products.

[0012] The method for in-situ pyrolysis of oil-rich coal over a wide depth range using supercritical CO2 according to the above system comprises the following steps:

[0013] 1) Drilling a number of injection wells and production wells vertically downward on the ground to reach shallow oil-rich coal and deep oil-rich coal, and excavating a number of first horizontal wells connecting the injection wells and production wells on the shallow oil-rich coal and deep oil-rich coal, and excavating a number of second horizontal wells perpendicular to the first horizontal wells on the plane where the first horizontal wells are located;

[0014] 2) Several temperature detectors are placed in the horizontal well to monitor the pyrolysis reaction temperature in real time;

[0015] 3) Based on the reservoir parameter information of shallow oil-rich coal and deep oil-rich coal, supercritical CO2 fluids of different temperatures and pressures are prepared using a supercritical CO2 generator, which flows from the injection well into the current block and infiltrates into the fracture network;

[0016] 4) Supercritical CO2 fluid flows along the injection well, horizontal well, and production well channels, convectively heating the coal seam in the current block. It then carries pyrolysis gas products out of the production well and uses temperature monitors installed at the production wellhead to monitor the degree of condensation of the pyrolysis products in real time.

[0017] 5) The supercritical CO2 fluid carries the pyrolysis gas products into the heat exchanger, reducing the product temperature to below the tar condensation temperature. The product then enters the gas-liquid separation device, where the condensed coal tar is collected in the oil storage device. The remaining gas enters the CO2 capture device to separate the pyrolysis gas and CO2, and the pyrolysis gas is collected in the gas storage device.

[0018] 6) Part of the separated CO2 is passed into the upper-level plot to absorb the residual heat of pyrolysis. The preheated CO2 enters the next-level supercritical CO2 generator to continue participating in the pyrolysis reaction. The other part of the separated CO2 is sealed in the semi-coke layer of the upper-level plot.

[0019] The injection well is also connected to a fracturing fluid pipeline for injecting fracturing fluid containing Fe, Co, and Ni metal components into the coal seam. The fracturing fluid is injected into the coal seam to form artificial fracturing cracks. The artificial cracks in different parts of the coal seam and the natural cracks in the coal seam together form an oil-rich coal seam fracture network.

[0020] The present invention establishes injection wells, first horizontal wells, second horizontal wells, and production wells in shallow and deep oil-rich coal layers, respectively. These wells, supplemented by temperature monitors, inject supercritical CO2 to achieve in-situ pyrolysis of the oil-rich coal. The pyrolysis products are then graded and processed. Different plots are simultaneously operated in a coordinated manner, utilizing the waste heat from one plot for the pyrolysis reaction in the next. CO2 serves as the heat carrier, and some of the CO2 is then sealed in the previous plot. The entire process achieves in-situ pyrolysis of oil-rich coal seams at varying burial depths and thicknesses, fully utilizing the heat from the pyrolysis process and avoiding heat waste. The supercritical CO2's enhanced heat and mass transfer improves the mining and utilization rate of the oil-rich coal, while also reducing CO2 emissions.

[0021] Furthermore, the present invention selects a fracturing fluid containing Fe, Co, and Ni metal components to increase the pyrolysis yield of oil-rich coal. The fracturing fluid is injected into the coal seam to form artificial fracturing cracks. The artificial cracks at different locations and the natural cracks in the coal seam together form a fracture network in the oil-rich coal seam.

[0022] In the current plot, the present invention uses a supercritical CO2 generator to produce supercritical CO2 fluids of different temperatures and pressures. The fluids flow from the injection well into the coal seam, penetrate into the fracture network, and heat and pyrolyze the oil-rich coal. The fluids then flow out of the production well along with the pyrolysis gas products. A temperature monitor is set near the production wellhead to monitor the degree of condensation of the pyrolysis products in real time based on the outflowing gas temperature.

[0023] The pyrolysis gas product first enters the heat exchanger to reduce the product temperature to above the tar condensation temperature, and then enters the gas-liquid separation device. The condensed coal tar is collected in the oil storage device. The remaining gas is separated into pyrolysis gas and CO2 through the CO2 capture device. The pyrolysis gas product is collected in the gas storage device. Part of the CO2 is passed into the previous block to absorb the residual heat of pyrolysis. The preheated CO2 flows out of the production well and enters the supercritical CO2 generator. The prepared supercritical CO2 is passed into the next block to continue participating in the pyrolysis reaction. The CO2 gas accumulated during the operation of the in-situ pyrolysis system of oil-rich coal continues to increase. The remaining CO2 separated from the current block is sealed in the semi-coke layer formed by the pyrolysis of the previous block, thereby reducing carbon emissions.

[0024] The present invention changes the monitored temperature in the horizontal well by adjusting the flow rate, temperature and pressure of the inlet supercritical CO2, thereby obtaining pyrolysis products with different component distributions.

[0025] The present invention has at least the following beneficial technical effects:

[0026] (1) Injection wells and production wells can be converted into each other, and the number of injection wells and production wells can be determined according to the budget cost, thereby improving the flexibility of the in-situ pyrolysis system.

[0027] (2) Injecting fracturing fluid containing Fe, Co, Ni and other components to perform fracturing transformation on the coal seam increases the permeability of the oil-rich coal, which is beneficial to the subsequent heat and mass transfer process; at the same time, the metal components in the fracturing fluid can also promote the pyrolysis reaction, thereby further improving the in-situ mining rate of the oil-rich coal.

[0028] (3) Supercritical CO2 is a fluid medium that has both gas and liquid properties. It has high diffusivity and low viscosity and can quickly dissolve organic matter. Using supercritical CO2 as a heat carrier can promote heat and mass transfer during the in-situ pyrolysis of oil-rich coal, thereby effectively improving the in-situ pyrolysis efficiency of oil-rich coal.

[0029] (4) The injection temperature and pressure parameters of supercritical CO2 are adjusted to make it suitable for convective heating of coal seams with different burial parameters, thereby achieving in-situ pyrolysis of oil-rich coal in a wide depth range and under different thickness conditions in one operating system, reducing system costs.

[0030] (5) The inlet parameters of supercritical CO2 are adjusted according to the real-time monitored outlet gas temperature. When the outlet gas temperature is close to the coal tar condensation temperature, the injection flow rate, temperature and pressure of supercritical CO2 are increased, which can reduce the loss of pyrolysis product tar and achieve full collection of coal tar.

[0031] (6) Changing the inlet flow rate, temperature, and pressure parameters of supercritical CO2 to achieve the ideal in-situ pyrolysis temperature conditions, and then adjusting the distribution of three-phase product components to achieve the production of tar and pyrolysis gas with different characteristics.

[0032] (7) A portion of the CO2 is introduced into the previous plot, absorbs the residual heat from pyrolysis, and then is introduced into the next plot to continue participating in the in-situ pyrolysis reaction, thereby reducing heat waste and realizing the cascade utilization of thermal energy.

[0033] (8) During the operation of the in-situ pyrolysis system, the accumulated CO2 continues to increase. Permanently sealing a portion of the CO2 in the pyrolysis semi-coke layer of the previous plot can effectively reduce carbon emissions.

[0034] (9) In coal seams within different depth ranges, the first horizontal well and the second horizontal well are arranged vertically and crosswise on the horizontal plane, which fully utilizes space resources and improves the mining utilization rate of oil-rich coal. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1 It is a structural schematic diagram of the present invention.

[0036] Description of reference numerals:

[0037] 1 is the rock layer, 2 is the shallow oil-rich coal, 3 is the deep oil-rich coal, 4 is the first horizontal well, 5 is the second horizontal well, 6 is the injection well, 7 is the production well, 9 is the fracturing fracture, 10 is the temperature monitor, 11 is the supercritical CO2 generator, 12 is the heat exchanger, 13 is the gas-liquid separation device, 14 is the CO2 capture device, 15 is the oil storage device, 16 is the gas storage device, 17 is the supercritical CO2 fluid, 18 is the pyrolysis gas, 19 is part of the CO2, 20 is another part of the CO2, 21 is the preheated CO2, 22 is the previous plot, 23 is the current plot, and 24 is the next plot. DETAILED DESCRIPTION

[0038] The present invention will be further described below in conjunction with the accompanying drawings:

[0039] See also Figure 1The present invention includes a plurality of land blocks connected step by step. Each land block is composed of a shallow oil-rich coal 2 and a deep oil-rich coal 3 below the rock layer 1. A plurality of injection wells 6 and production wells 7 are vertically excavated in the shallow oil-rich coal 2 and the deep oil-rich coal 3. A plurality of first horizontal wells 4 arranged in parallel and a plurality of second horizontal wells 5 perpendicular to the first horizontal wells 4 are excavated on the shallow oil-rich coal 2 and the deep oil-rich coal 3 at the bottom of the injection wells 6 and the production wells 7. The first horizontal wells 4 and the second horizontal wells 5 are arranged vertically crosswise on the horizontal plane. The injection wells 6, the production wells 7, the first horizontal wells 4 and the second horizontal wells 5 are vertically crosswise arranged on the horizontal plane. The combination of the horizontal well 4 and the second horizontal well 5 forms a fluid heating channel for in-situ pyrolysis of oil-rich coal. Several temperature detectors 10 are placed in the horizontal well to monitor the pyrolysis reaction temperature in real time. A temperature monitor 10 is set at the wellhead of the production well to control the condensation degree of the pyrolysis product in real time. The present invention also connects the injection well 6 to a fracturing fluid pipeline for conveying fracturing fluid containing Fe, Co, and Ni metal components. The fracturing fluid is injected into the coal seam to form artificial fracturing cracks 9. The artificial cracks 9 at different locations and the natural cracks in the coal seam together form a fracture network of the oil-rich coal seam.

[0040] The injection well 6 is connected to a supercritical CO2 generator 11 for preparing supercritical CO2 fluid 17 of different temperatures and pressures, wherein the initial pressure of the supercritical CO2 fluid 17 is greater than the coal seam reservoir pressure, and the pyrolysis gas product enters the heat exchanger 12 and the gas-liquid separation device 13 in sequence through the production well 7, and the condensed coal tar is collected in the oil storage device 15. The gas is separated by the CO2 capture device 14 to obtain pyrolysis gas 18 and CO2, and the pyrolysis gas product 18 is collected in the gas storage device 16. Part of the CO2 19 separated by the CO2 capture device 14 is injected into the upper-level block 22 through the injection well 6 of the upper-level block to absorb the residual heat of pyrolysis. The preheated CO2 21 after preheating flows out from the production well 7 and enters the supercritical CO2 generator 11 of the next-level block 24. Another part of the CO2 20 separated by the CO2 capture device 14 is injected into the semi-coke layer formed by pyrolysis of the upper-level block through the injection well 6 of the upper-level block.

[0041] The present invention comprehensively considers the preparation of supercritical CO2, the in-situ pyrolysis of oil-rich coal within a wide depth range, the joint operation of different plots, and the multi-path optimization treatment of CO2. Combined with a unique well layout method, the component distribution of the in-situ pyrolysis three-phase products of coal seams at different depths and thicknesses is adjusted, thereby improving the mining utilization rate of oil-rich coal and realizing full utilization of thermal energy.

[0042] The method of the present invention for in-situ pyrolysis of oil-rich coal in a wide range of depths using supercritical CO2 comprises the following steps:

[0043] 1) Drilling a plurality of injection wells 6 and production wells 7 vertically downward on the ground to reach the shallow oil-rich coal 2 and the deep oil-rich coal 3, and excavating a plurality of first horizontal wells 4 connecting the injection wells 6 and the production wells 7 on the shallow oil-rich coal 2 and the deep oil-rich coal 3, and excavating a plurality of second horizontal wells 6 perpendicular to the first horizontal wells 4 on the same plane as the first horizontal wells 4;

[0044] 2) Several temperature detectors 10 are placed in the horizontal well to monitor the pyrolysis reaction temperature in real time;

[0045] 3) A fracturing fluid containing Fe, Co, and Ni metal components is injected into the coal seam through a fracturing fluid pipeline connected to the injection well 6 to perform fracturing on the coal seam. The fracturing fluid is injected into the coal seam to form artificial fracturing cracks 9. The artificial cracks 9 at different locations and the natural cracks in the coal seam together form a fracture network in the oil-rich coal seam. The formed artificial fracturing cracks 14 help improve the pyrolysis efficiency of the oil-rich coal.

[0046] 4) Based on the reservoir parameter information of the shallow oil-rich coal 2 and the deep oil-rich coal 3, a supercritical CO2 generator 10 is used to prepare supercritical CO2 fluid 27 of different temperatures and pressures. The supercritical CO2 fluid 27 flows from the injection well 6 into the current block 23 and penetrates the fracture network. In addition to its own heat carrying capacity, the supercritical CO2 fluid 17 can enhance heat and mass transfer during the in situ pyrolysis of the oil-rich coal due to its special fluid properties.

[0047] 5) Supercritical CO2 fluid 17 flows along injection well 6, horizontal well, and production well 7, convectively heating the coal seam in the current plot 23. It then carries pyrolysis gas products out of production well 7. A temperature monitor 10 is installed near the production wellhead to monitor the degree of condensation of the pyrolysis products in real time based on the gas outflow temperature.

[0048] 6) The supercritical CO2 fluid 17 carries the pyrolysis gas products into the heat exchanger 12, causing the product temperature to drop to above the tar condensation temperature. The products then enter the gas-liquid separation device 13, where the condensed coal tar is collected in the oil storage device 15. The remaining gas enters the CO2 capture device 14, where pyrolysis gas 18 and CO2 are separated. The pyrolysis gas 18 is collected in the gas storage device 16.

[0049] 7) The separated portion of CO2 19 is passed into the upper-level plot 22 to absorb the residual heat of pyrolysis. The preheated CO2 21 enters the supercritical CO2 generator 11, and the resulting supercritical fluid CO2 is then passed into the lower-level plot 24 to continue participating in the pyrolysis reaction. Due to the increasing accumulation of CO2 during the operation of the oil-rich coal in-situ pyrolysis system, in order to reduce carbon emissions, the remaining portion of the separated CO2 20 is sealed in the semi-coke layer of the upper-level plot 22.

[0050] The supercritical CO2 fluid 17 of the present invention is a fluid medium with both gas and liquid properties, with high diffusivity and low viscosity, and can quickly dissolve organic matter, which helps to enhance heat and mass transfer during the in-situ pyrolysis of oil-rich coal. According to the reservoir parameter information of the shallow oil-rich coal 2 and the deep oil-rich coal 3, respectively, a supercritical CO2 generator 11 is used to prepare supercritical CO2 fluids 17 of different temperatures and pressures, which flow from the injection well into the current block 23, convection-heat the coal seam along the fluid channel, and at the same time penetrate into the fracture network. After the oil-rich coal is heated and pyrolyzed, pyrolysis solid products and pyrolysis gas products are generated. The supercritical CO2 fluid 17 flows out of the production well together with the pyrolysis gas products, and a temperature monitor 10 is set near the production wellhead to control the condensation degree of the pyrolysis products in real time according to the gas outflow temperature.

[0051] Supercritical CO2 fluid 17, carrying pyrolysis gas products, first enters heat exchanger 12, lowering the product temperature to below the tar condensation temperature. It then enters gas-liquid separation device 13, where the condensed coal tar is collected in oil storage device 15. The remaining gas enters CO2 capture device 14, where it is separated into pyrolysis gas 18 and CO2. Pyrolysis gas 18 is collected in gas storage device 16, and a portion of CO2 19 is passed into the upper-level block 22 to absorb residual heat from the pyrolysis formation. The preheated CO2 21 flows out of the production well and enters supercritical CO2 generator 11, where supercritical CO2 fluid 17 is produced and then passed into the lower-level block 24 to continue participating in the in-situ pyrolysis reaction. The semi-coke layer formed after pyrolysis has a well-developed pore structure and a large specific surface area, thus possessing a certain gas storage capacity. During the operation of the in-situ pyrolysis system for oil-rich coal, the accumulated CO2 gas continues to increase. Therefore, the remaining CO2 20 separated from the current plot 23 is sealed in the solid semi-coke layer formed by the pyrolysis of the upper-level plot 22, which can reduce carbon emissions.

[0052] The above content is a further detailed description of the present invention in combination with specific preferred embodiments. It cannot be considered that the specific embodiments of the present invention are limited to these. For ordinary technicians in the technical field to which the present invention belongs, they can make several simple deductions or substitutions without departing from the concept of the present invention, which should be regarded as belonging to the scope of patent protection determined by the submitted claims of the present invention.

Claims

1. A system for supercritical CO2 in-situ pyrolysis of oil-rich coal over a wide depth range, characterized in that: The invention comprises a plurality of land blocks connected step by step, each of which is composed of a shallow oil-rich coal (2) and a deep oil-rich coal (3) below a rock layer (1), a plurality of injection wells (6) and production wells (7) are vertically excavated in the shallow oil-rich coal (2) and the deep oil-rich coal (3), a plurality of first horizontal wells (4) arranged in parallel and a plurality of second horizontal wells (5) perpendicular to the first horizontal wells (4) are excavated on the shallow oil-rich coal (2) and the deep oil-rich coal (3) at the bottom ends of the injection wells (6) and the production wells (7), the combination of the injection wells (6), the production wells (7), the first horizontal wells (4) and the second horizontal wells (5) forms a fluid heating channel for in-situ pyrolysis of the oil-rich coal, and a plurality of temperature detectors (10) are placed in the horizontal wells for real-time monitoring of the pyrolysis reaction temperature; The injection well (6) is connected to a supercritical CO2 generator (11) for preparing supercritical CO2 fluid (17) of different temperatures and pressures. The pyrolysis gas product enters the heat exchanger (12) and the gas-liquid separation device (13) in sequence through the production well (7). The coal tar obtained by condensation is collected in the oil storage device (15). The gas is separated into pyrolysis gas (18) and CO2 by the CO2 capture device (14). The pyrolysis gas (18) is collected in the gas storage device (16) and is then separated into the CO2 by the CO2 capture device (14).

2. Part of the CO2 (19) separated by the capture device (14) is injected into the previous level land block (22) through the injection well (6) of the previous level land block to absorb the residual heat of pyrolysis. The preheated CO2 (21) flows out from the production well (7) and enters the supercritical CO2 generator (11) of the next level land block (24). Another part of the CO2 (20) separated by the CO2 capture device (14) is injected into the semi-coke layer formed by pyrolysis of the previous level land block through the injection well (6) of the previous level land block; The injection well (6) is also connected to a fracturing fluid pipeline for conveying fracturing fluid, and the fracturing fluid is injected into the coal seam to form artificial fracturing cracks (9), and the fracturing cracks (9) at different locations and the natural cracks in the coal seam are jointly constructed to form an oil-rich coal seam crack network; The initial pressure of the supercritical CO2 fluid (17) is greater than the coal seam reservoir pressure; The first horizontal well (4) and the second horizontal well (5) are arranged vertically and crosswise on the horizontal plane.

2. The system for supercritical CO2 in-situ pyrolysis of oil-rich coal in a wide depth range according to claim 1, characterized in that: The fracturing fluid contains Fe, Co and Ni metal components.

3. The system for supercritical CO2 in-situ pyrolysis of oil-rich coal in a wide depth range according to claim 1, characterized in that: The wellhead of the production well is provided with a temperature monitor (10) for real-time control of the condensation degree of the pyrolysis products.

4. A method for in-situ pyrolysis of oil-rich coal over a wide depth range using supercritical CO2 as claimed in any one of claims 1 to 3, characterized in that The following steps are involved: 1) Drilling a plurality of injection wells (6) and production wells (7) vertically downward on the ground to reach the shallow oil-rich coal (2) and the deep oil-rich coal (3), and excavating a plurality of first horizontal wells (4) connecting the injection wells (6) and the production wells (7) on the shallow oil-rich coal (2) and the deep oil-rich coal (3), and excavating a plurality of second horizontal wells (5) perpendicular to the first horizontal wells (4) on the plane where the first horizontal wells (4) are located; 2) a plurality of temperature detectors (10) are placed in the horizontal well to monitor the pyrolysis reaction temperature in real time; 3) targeting the reservoir parameter information of the shallow oil-rich coal (2) and the deep oil-rich coal (3), respectively, a supercritical CO2 generator (11) is used to prepare supercritical CO2 fluid (17) of different temperatures and pressures, which flows from the injection well (6) into the current block (23) and penetrates into the fracture network; 4) The supercritical CO2 fluid (17) flows along the injection well (6), the horizontal well and the production well (7) and convectively heats the coal seam of the current block (23), and then carries the pyrolysis gas products out of the production well (7) and controls the condensation degree of the pyrolysis products in real time through the temperature monitor (10) set at the production wellhead; 5) The supercritical CO2 fluid (17) carries the pyrolysis gas product into the heat exchanger (12), causing the product temperature to drop below the tar condensation temperature, and then enters the gas-liquid separation device (13), and the condensed coal tar is collected in the oil storage device (15); the remaining gas enters the CO2 capture device (14), and the pyrolysis gas (18) and CO2 are separated, and the pyrolysis gas (18) is collected in the gas storage device (16); 6) The separated portion of CO2 (19) is passed into the upper-level land block (22) to absorb the residual heat of pyrolysis, and the preheated CO2 (21) enters the next-level supercritical CO2 generator (11) to continue participating in the pyrolysis reaction, and the other portion of CO2 (20) separated is sealed in the semi-coke layer of the upper-level land block (22).

5. The method for in-situ supercritical CO2 pyrolysis of oil-rich coal over a wide depth range according to claim 4, characterized in that: The injection well (6) is also connected to a fracturing fluid pipeline for injecting fracturing fluid containing Fe, Co, and Ni metal components into the coal seam. The fracturing fluid is injected into the coal seam to form artificial fracturing cracks (9). The fracturing cracks (9) at different locations and the natural cracks in the coal seam together form an oil-rich coal seam crack network.

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