System and method for supercritical CO2 in-situ pyrolysis of wide-depth-range oil-rich coal

Abstract

The invention discloses a system and a method for supercritical CO2 in-situ pyrolysis of wide-depth-range oil-rich coal, an injection well, a first horizontal well, a second horizontal well and a production well are respectively arranged in shallow-layer oil-rich coal and deep-layer oil-rich coal, a temperature monitor is supplemented, supercritical CO2 is injected to realize in-situ pyrolysis of the oil-rich coal, and the in-situ pyrolysis of the oil-rich coal is realized. The pyrolysis products are subjected to grading treatment, meanwhile, different land parcels are operated in a combined mode, waste heat of the previous land parcel is used for the pyrolysis reaction of the next land parcel, CO2 is a heat carrying medium, and then part of CO2 is sealed in the previous land parcel. In the whole process, in-situ pyrolysis of the oil-rich coal seam in different burial depths and thickness ranges is achieved, heat in the pyrolysis process is fully utilized, heat waste is avoided, and the mining utilization rate of the oil-rich coal is increased through the promoting effect of supercritical CO2 on heat and mass transfer; and meanwhile, the strategic goals of CO2 emission reduction and carbon neutralization promotion are achieved.

Description

Technical Field

[0001] The present invention relates to a pyrolysis system and method for oil-rich coal, and in particular to a supercritical CO 2 A system and method for in-situ pyrolysis of oil-rich coal over a wide depth range. Background Art

[0002] China is currently the world's largest importer of crude oil and natural gas, and its dependence on foreign oil and gas resources has reached an extremely dangerous level. In order to ensure the normal progress of economic production and people's lives, it is imperative to effectively increase oil and gas production and ensure national energy security. Using coal-to-oil technology to increase oil and gas production is a reliable way. Oil-rich coal is a type of coal with a tar content of 7-12%. The rich oil-rich coal in western my country constitutes a potential oil and gas resource. However, the environmental pollution and casualties caused by the traditional coal mining and utilization process cannot be ignored. Based on this, in recent years, a new concept of in-situ pyrolysis of oil-rich coal has been proposed, that is, directly heating the oil-rich coal in situ underground, pyrolyzing it to generate oil and gas products and extracting them to the ground. This technology can not only effectively avoid the pollution emissions and casualties involved in the mining and coal combustion process, but also increase 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 of shallow coal and deep coal. At the same time, the in-situ heating performance of traditional fluid media needs to be improved. Supercritical CO 2 It is a special fluid with high diffusivity and low viscosity. 2 Convective heating of oil-rich coal helps to enhance heat and mass transfer during in-situ pyrolysis of oil-rich coal. 2 The inlet parameters of supercritical CO can achieve in-situ pyrolysis of oil-rich coal seams at different burial depths and thicknesses. 2 The system and method for in-situ pyrolysis of oil-rich coal over a wide depth range has very important practical significance. Summary of the invention

[0004] The present invention aims to provide a supercritical CO 2 A system and method for in-situ pyrolysis of oil-rich coal over a wide depth range.

[0005] To achieve the above-mentioned purpose, the system of the present invention comprises a plurality of land blocks connected step by step, each land block is composed of shallow oil-rich coal and deep oil-rich coal below the rock layer, a plurality of injection wells and production wells are vertically excavated in the shallow oil-rich coal and deep oil-rich coal, a plurality of first horizontal wells arranged in parallel and a plurality of second horizontal wells perpendicular to the first horizontal wells are excavated on the shallow oil-rich coal and deep oil-rich coal at the bottom of the injection wells and the production wells, the combination of the injection wells, the production wells, the first horizontal wells and the second horizontal wells form a fluid heating channel for in-situ pyrolysis of the oil-rich coal, and a plurality of temperature detectors for real-time monitoring of the pyrolysis reaction temperature are placed in the horizontal wells;

[0006] The injection well is connected to a supercritical CO 2 Fluid supercritical CO 2 The pyrolysis gas product enters the heat exchanger and gas-liquid separation device through the production well in turn. The coal tar obtained by condensation is collected in the oil storage device. The gas is passed through the CO 2 The capture device separates the pyrolysis gas and CO 2 The pyrolysis gas products are collected in the gas storage device and then 2 Part of the CO separated by the capture device 2 The preheated CO 2 Supercritical CO flowing out of the production well and into the next level of land 2 Generator, via CO 2 Another part of CO separated by the capture device 2 It is injected into the semi-coke layer formed by pyrolysis in the previous level land through the injection well of the previous level land.

[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 a crack network of the oil-rich coal seam.

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

[0009] The supercritical CO 2 The initial fluid pressure 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] According to the above system, supercritical CO 2 A method for in-situ pyrolysis of oil-rich coal over a wide depth range comprises the following steps:

[0013] 1) Drilling a number of injection wells and production wells vertically downward on the ground to reach the shallow oil-rich coal and the deep oil-rich coal, and excavating a number of first horizontal wells connecting the injection wells and the production wells on the shallow oil-rich coal and the 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 CO 2 Generators produce supercritical CO at different temperatures and pressures 2 fluids, which flow from injection wells into the current block and penetrate into the fracture network;

[0016] 4) Supercritical CO 2 The fluid flows along the injection well, horizontal well and production well channels and performs convection heating on the coal seam in the current plot, and then carries the pyrolysis gas products out of the production well to control the condensation degree of the pyrolysis products in real time through the temperature monitor set at the production wellhead;

[0017] 5) Supercritical CO 2 The fluid carries the pyrolysis gas product into the heat exchanger, reducing the product temperature to below the tar condensation temperature, and then enters the gas-liquid separation device to collect the condensed coal tar into the oil storage device; the remaining gas enters the CO 2 Capture device to separate pyrolysis gas and CO 2 , the pyrolysis gas is collected in a gas storage device;

[0018] 6) The separated part of CO 2 The preheated CO 2 Entering the next level of supercritical CO 2 Generator, continue to participate in the pyrolysis reaction, separate the other part of CO 2 Seal it 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 and the natural cracks in the coal seam together form an oil-rich coal seam fracture network.

[0020] The present invention respectively opens an injection well, a first horizontal well, a second horizontal well and a production well in the shallow oil-rich coal and the deep oil-rich coal, and uses a temperature monitor to inject supercritical CO 2To achieve in-situ pyrolysis of oil-rich coal, the pyrolysis products are graded and processed, and different plots are operated jointly to use the waste heat of the previous plot for the pyrolysis reaction of the next plot. 2 is the heat carrier, and then part of the CO 2 The whole process realizes the in-situ pyrolysis of oil-rich coal seams at different burial depths and thicknesses, making full use of the heat of the pyrolysis process and avoiding heat waste. 2 The promotion of heat and mass transfer increases the mining and utilization rate of oil-rich coal; at the same time, it realizes CO 2 Emission reduction will help promote the strategic goal of carbon neutrality.

[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, injects the fracturing fluid into the coal seam to form artificial fracturing cracks, and the artificial cracks at different locations and the natural cracks in the coal seam together form a crack network of the oil-rich coal seam;

[0022] In the current plot, the present invention uses supercritical CO 2 The generator produces supercritical CO at different temperatures and pressures 2 Fluid flows into the coal seam from the injection well, penetrates into the fracture network to heat and pyrolyze the oil-rich coal, and then flows out of the production well with the pyrolysis gas products. A temperature monitor is set near the production wellhead to control the condensation degree of the pyrolysis products in real time according to the gas outflow 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 to collect the condensed coal tar into the oil storage device, and the remaining gas is passed through the CO 2 The capture device separates the pyrolysis gas and CO 2 , collect the pyrolysis gas products in the gas storage device, and part of the CO 2 The preheated CO 2 Flowing out from the production well and into the supercritical CO 2 Generator to prepare supercritical CO 2 The next plot is passed on to continue the pyrolysis reaction. The CO accumulated during the operation of the in-situ pyrolysis system of oil-rich coal is 2 The gas is increasing, and the remaining CO 2 It is sealed in the semi-coke layer formed by pyrolysis of the previous plot, thereby reducing carbon emissions.

[0024] The present invention adjusts the inlet supercritical CO 2 The flow rate, temperature and pressure are adjusted to change the temperature in the monitored horizontal well, 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 into the coal seam for fracturing and transformation 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 CO 2 It is a fluid medium with both gas and liquid properties, with high diffusivity and low viscosity, and can quickly dissolve organic matter. It uses supercritical CO 2 As a heat carrier, it 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) Adjustment of supercritical CO 2 The injection temperature and pressure parameters make it suitable for convective heating of coal seams under different burial parameters, thereby realizing in-situ pyrolysis of oil-rich coal under a wide depth range and different thickness conditions in one operating system, reducing the system cost.

[0030] (5) Adjust the supercritical CO according to the outlet gas temperature monitored in real time 2 When the outlet gas temperature is close to the coal tar condensation temperature, increase the supercritical CO 2 The injection flow rate, temperature and pressure can reduce the loss of pyrolysis product tar and achieve sufficient collection of coal tar.

[0031] (6) Changing supercritical CO 2 The inlet flow rate, temperature and pressure parameters can be adjusted to achieve the ideal in-situ pyrolysis temperature conditions, and then the three-phase product component distribution can be adjusted to achieve the production of tar and pyrolysis gas with different characteristics.

[0032] (7) Part of CO 2 It is passed into the previous block, absorbs the residual heat from pyrolysis, and then is passed into the next block to continue participating in the in-situ pyrolysis reaction, thus reducing heat waste and achieving the cascade utilization of thermal energy.

[0033] (8) During the operation of the in-situ pyrolysis system, the accumulated CO 2 Increasingly, part of the CO 2 Permanent storage 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 wells and the second horizontal wells 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 rock, 2 is shallow oil-rich coal, 3 is 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, and 11 is the supercritical CO 2 generator, 12 is a heat exchanger, 13 is a gas-liquid separation device, 14 is a CO 2 Capture device, 15 is an oil storage device, 16 is a gas storage device, 17 is a supercritical CO 2 Fluid, 18 is pyrolysis gas, 19 is part of CO 2 , 20 is the other part of CO 2 , 21 is preheating CO 2 , 22 is the previous plot, 23 is the current plot, and 24 is the next plot. DETAILED DESCRIPTION

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

[0039] See also Figure 1 The present invention comprises 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 a rock layer 1, a plurality of injection wells 6 and a production well 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 arranged vertically crosswise 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. A number of temperature detectors 10 for real-time monitoring of the pyrolysis reaction temperature are placed in the horizontal well, and a temperature monitor 10 for real-time control of the condensation degree of the pyrolysis product is arranged at the wellhead of the production well. In the present invention, a fracturing fluid pipeline for conveying fracturing fluid containing Fe, Co, and Ni metal components is also connected to the injection well 6. The fracturing fluid is injected into the coal seam to form artificial fracturing cracks 9. The artificial cracks 9 at different positions 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 CO 2Supercritical CO of Fluid 17 2 Generator 11, wherein supercritical CO 2 The initial pressure of fluid 17 is greater than the coal seam reservoir pressure. The pyrolysis gas product enters the heat exchanger 12 and the gas-liquid separation device 13 through the production well 7 in sequence. The condensed coal tar is collected in the oil storage device 15. The gas is passed through the CO 2 The capture device 14 separates the pyrolysis gas 18 and CO 2 The pyrolysis gas product 18 is collected in the gas storage device 16 and then 2 The capture device 14 separates part of the CO 2 19 is injected into the upper-level plot 22 through the injection well 6 of the upper-level plot to absorb the residual heat of pyrolysis, and the preheated CO 2 21 The supercritical CO flowing out of the production well 7 and entering the next level plot 24 2 Generator 11, via CO 2 Another part of CO separated by the capture device 14 2 20 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.

[0041] The present invention comprehensively considers supercritical CO 2 preparation, in-situ pyrolysis of oil-rich coals over a wide depth range, joint operation of different plots, and CO 2 Through multi-path optimization processing and a unique well layout method, the component distribution of the in-situ pyrolysis three-phase products of coal seams at different depths and thicknesses was adjusted, thereby improving the mining utilization rate of oil-rich coal and achieving full utilization of thermal energy.

[0042] The supercritical CO 2 A method for in-situ pyrolysis of oil-rich coal over a wide depth range comprises the following steps:

[0043] 1) Drilling a number 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 number 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 number of second horizontal wells 6 perpendicular to the first horizontal wells 4 on the plane where the first horizontal wells 4 are located;

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

[0045] 3) injecting a fracturing fluid containing Fe, Co, and Ni metal components into the coal seam through a fracturing fluid pipeline connected to the injection well 6 to perform fracturing transformation 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 crack network of the oil-rich coal seam. The formed artificial fracturing cracks 14 help to improve the pyrolysis efficiency of the oil-rich coal.

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

[0047] 5) Supercritical CO 2 The fluid 17 flows along the injection well 6, the horizontal well and the production well 7 and performs convection heating on the coal seam of the current block 23, and then carries the pyrolysis gas product out of the production well 7. A temperature monitor 10 is set near the production wellhead to control the condensation degree of the pyrolysis product in real time according to the gas outflow temperature.

[0048] 6) Supercritical CO 2 Fluid 17 carries the pyrolysis gas product into heat exchanger 12, so that the product temperature is reduced to above the tar condensation temperature, and then enters gas-liquid separation device 13, collects the condensed coal tar into oil storage device 15, and the remaining gas enters CO 2 Capture device 14, separates pyrolysis gas 18 and CO 2 , collecting the pyrolysis gas 18 in the gas storage device 16;

[0049] 7) The separated part of CO 2 19 is passed into the upper level plot 22 to absorb the waste heat from pyrolysis, and the preheated CO 2 21 Entering supercritical CO 2 Generator 11, the prepared supercritical fluid CO 2 Then it is passed to the next level block 24 to continue to participate in the pyrolysis reaction. 2 In order to reduce carbon emissions, another part of the separated CO 2 20 is sealed in the semi-coke layer of the upper-level plot 22.

[0050] The supercritical CO of the present invention 2 Fluid 17, as a fluid medium with both gas and liquid properties, has 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. 2 Generator 11 produces supercritical CO at different temperatures and pressures 2Fluid 17 flows from the injection well into the current block 23, convectively heats the coal seam along the fluid channel, and penetrates into the fracture network. The oil-rich coal is pyrolyzed at elevated temperatures to produce pyrolysis solid products and pyrolysis gas products. Supercritical CO 2 The fluid 17 flows out of the production well together with the pyrolysis gas products. A temperature monitor 10 is arranged near the production wellhead to control the condensation degree of the pyrolysis products in real time according to the outflow temperature of the gas.

[0051] Supercritical CO 2 Fluid 17 carrying pyrolysis gas products first enters heat exchanger 12 to reduce the product temperature to below the tar condensation temperature, and then enters gas-liquid separation device 13 to collect the condensed coal tar into oil storage device 15. The remaining gas enters CO 2 The capture device 14 separates the pyrolysis gas 18 and CO 2 , the pyrolysis gas 18 is collected in the gas storage device 16, and part of the CO 2 19 is passed into the upper level block 22 to absorb the residual heat of the stratum after pyrolysis, and the preheated CO 2 21 Flows out from the production well and enters the supercritical CO 2 Generator 11, to prepare supercritical CO 2 Fluid 17 is then passed into the next 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 having a certain gas storage capacity. During the operation of the in-situ pyrolysis system for oil-rich coal, the accumulated CO 2 The gas is increasing, so the remaining CO2 separated from the current plot 23 is 2 20 Sealing in the solid semi-coke layer formed by pyrolysis of the upper-level plot 22 can reduce carbon emissions.

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

Claims

1. A system for supercritical CO2 in-situ pyrolysis of oil-rich coal in 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 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 by the CO2 capture device (14) to obtain pyrolysis gas (18) and CO2. The pyrolysis gas product (18) is collected in the gas storage device (16) and then filtered by C Part of the CO2 (19) separated by the O2 capture device (14) is injected into the previous block (22) through the injection well (6) of the previous block to absorb residual heat from pyrolysis. The preheated CO2 (21) flows out from the production well (7) and enters the supercritical CO2 generator (11) of the next 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 block through the injection well (6) of the previous block.

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 injection well (6) 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 (9). The artificial cracks (9) at different locations and the natural cracks in the coal seam together form an oil-rich coal seam crack network.

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

4. 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 initial pressure of the supercritical CO2 fluid (17) is greater than the coal seam reservoir pressure.

5. 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 first horizontal well (4) and the second horizontal well (5) are arranged vertically and crosswise on a horizontal plane.

6. 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 monitoring of the condensation degree of the pyrolysis products.

7. A method for in-situ pyrolysis of oil-rich coal in a wide range of depths using supercritical CO2 as claimed in any one of claims 1 to 6, 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 (6) 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) according to 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 (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 performs convection heating on the coal seam of the current plot (23), and then carries the pyrolysis gas product out of the production well (7) and controls the condensation degree of the pyrolysis product 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), so that the product temperature is reduced to 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 part of CO2 (19) is introduced into the previous block (22) to absorb the residual heat of pyrolysis, and the preheated CO2 (21) enters the next supercritical CO2 generator (11) to continue to participate in the pyrolysis reaction, and the other part of CO2 (20) separated is sealed in the semi-coke layer of the previous block (22).

8. The method for in-situ pyrolysis of oil-rich coal in a wide range of depths using supercritical CO2 according to claim 7, 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 artificial 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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