Underground in-situ conversion and economical efficiency evaluation method for oil-rich coal

Abstract

The invention relates to the technical field of oil-rich coal mining, in particular to an oil-rich coal underground in-situ conversion and economical efficiency evaluation method which comprises the following steps: step 1, pre-collecting in a to-be-mined area and obtaining associated geological data; 2, establishing a geological virtual model based on the geological data; 3, performing simulation condition arrangement on the simulation device based on the geological data, setting the sizes of cracks of the oil-rich coal sample in different directions, and recording corresponding crack change parameters and pyrolysis product gas under experimental conditions; 4, on the basis of fracture distribution coordinates in the geological virtual model, fracture change parameters and pyrolysis product gas corresponding to experiment conditions are obtained, the fracture expansion range is obtained, and a reinforcement well is arranged; the position coordinates of the extraction well in the geological virtual model are adjusted based on the migration range of the pyrolysis product gas; the stability of the original underground geology is maintained, the heat loss is reduced by reducing oil gas diffusion, the oil gas pyrolysis conversion efficiency is guaranteed, and the economical efficiency is improved.

Description

Technical Field

[0001] The invention relates to the technical field of oil-rich coal mining, and in particular to an underground in-situ conversion and economic evaluation method of oil-rich coal. Background Art

[0002] In the process of oil-rich coal mining, unlike conventional oil and gas resource development, the in-situ pyrolysis conversion process of oil-rich coal is achieved through drilling construction and artificial seam creation to form a through channel in the underground coal seam, and then by injecting heat carrier fluid or electric heating, the oil-rich coal is pyrolyzed underground in situ, and the oil and gas resources obtained by pyrolysis are extracted.

[0003] Among the existing coal seam heating methods, convection heating is usually used for product recycling. By injecting high-temperature heat-carrying fluid into artificial fractures to heat the coal seam, the oil and gas produced by the pyrolysis of oil-rich coal or oil shale can be relatively easier to be extracted from the bottom of the well with the flow of the fluid, thus realizing the recycling of cracking gas. However, the convection heating method is easily affected by formation water and coal seam permeability, resulting in large heat losses during the injection process, and oil and gas products may escape from the pyrolysis zone through cracks, causing water pollution. Therefore, multiple factors need to be considered when conducting underground pyrolysis of oil-rich coal. It is necessary to improve the efficiency of pyrolysis products while ensuring the economy of the product process and the influence of surrounding geology. Therefore, the pyrolysis process of oil-rich coal under different temperature conditions can be reversed through the principle of chemical kinetics, and the corresponding pyrolysis process model can be established to provide a reference for evaluating the underground in-situ transformation and economic evaluation of oil-rich coal. Summary of the invention

[0004] To solve the above problems, the present invention provides an underground in-situ conversion and economic evaluation method for oil-rich coal, which is used to simulate and determine the extraction points and consolidation points, maintain the stability of the original underground geology, reduce heat loss by reducing oil and gas diffusion, ensure the efficiency of pyrolysis conversion of oil and gas, and improve economic efficiency.

[0005] In order to achieve the above-mentioned object, the technical scheme of the present invention is as follows: an underground in-situ conversion method of oil-rich coal, comprising the following steps: step 1, collecting geological data, pre-collecting and obtaining related geological data in the area to be mined, the geological data including coal seam composition parameters, geological fracture parameters, pyrolysis atmosphere parameters, and the position coordinates of pre-set injection wells and extraction wells;

[0006] Step 2: Establish a geological virtual model based on geological data, then mark the geological virtual model based on the location coordinates of the injection well and the extraction well, and add fracture distribution coordinates to the corresponding positions of the geological virtual model based on geological fracture parameters;

[0007] Step 3: Arrange the simulation conditions of the oil-rich coal sample in the simulation device based on the pyrolysis atmosphere parameters, set the crack sizes of the oil-rich coal sample in different directions based on the geological crack parameters, and then record the corresponding crack change parameters and pyrolysis product gases under the experimental conditions;

[0008] Step 4: Based on the fracture distribution coordinates of different geological fracture parameters in the geological virtual model, obtain the fracture change parameters and pyrolysis product gases corresponding to the experimental conditions, compare the fracture change parameters with the geological fracture parameters, obtain the fracture expansion range, and arrange reinforcement wells according to the fracture expansion range; then adjust the position coordinates of the extraction wells in the geological virtual model based on the migration range of the pyrolysis product gases.

[0009] The technical principles of the above scheme are as follows:

[0010] A simulation device is established through geological data to understand the influence of fracture change parameters and pyrolysis product gases under different experimental conditions. By combining simulation with practice, the layout of reinforcement wells or extraction wells is adjusted to provide a reference for actual mining.

[0011] The above scheme has the following beneficial effects:

[0012] 1. This plan reduces the pressure of oil-rich coal on the surrounding strata during in-situ pyrolysis by adjusting the layout of reinforcement wells or extraction wells, maintains the original geology from external changes, and understands the possible crack diffusion based on the geological crack change parameters to determine the geological consolidation points.

[0013] 2. This scheme prevents the pyrolysis product gas from diffusing around by arranging reinforcement wells, which makes it inconvenient to collect the gas later and easily causes pollution to the original groundwater. By adjusting the position of the extraction wells, the coal seam pressure can be controlled in time and a sufficiently high pressure can be maintained to extract the gas. The extraction wells can also be used as the location to reinforce the geological fractures to reduce the subsequent impact of the fractures.

[0014] 3. This scheme adopts a combination of simulation and practice to ensure the continuous and effective operation of the pyrolysis product gas, so as to improve the efficiency of pyrolysis conversion to oil and gas by reducing external interference.

[0015] Furthermore, the simulation device includes a tank body, in which a plurality of crack plates are arranged, and gaps are provided between adjacent crack plates; a plurality of electric heating tubes for heating are provided in the crack plates;

[0016] A stepped fixing block is provided between adjacent crack plates, a rotating shaft is fixedly connected to the fixing block, the crack plate and the rotating shaft are rotated together, and a clamping shaft is threadedly connected to one end of the crack plate away from the rotating shaft, and the crack plate is fixedly connected to the tank body through the clamping shaft;

[0017] A pressure shaft is provided between the tank body and the crack plate, one end of the pressure shaft is fixedly connected to the tank body, a compression chamber is provided in the pressure shaft, a piston is slidably fitted in the compression chamber, an adjusting rod is fixedly connected to one end of the piston, an end of the adjusting rod away from the piston is hinged to an end of the crack plate away from the rotating shaft; an exhaust pipe is also connected to the end of the compression chamber close to the crack plate, the exhaust pipe is a Y-shaped pipe, the other end of the exhaust pipe is connected to the center of the crack plate, the other end of the exhaust pipe is connected to the outside of the tank body, and a three-phase solenoid valve is connected at the intersection of the exhaust pipes; the three-phase solenoid valve is electrically connected to a control panel;

[0018] The tank body is connected with a plurality of replacement pipes, the replacement pipes are located between adjacent crack plates, and the replacement pipes are connected with valves.

[0019] Beneficial effects: The gaps formed by different crack plates are used to simulate geological crack parameters, and the crack plates are supported by a pressure shaft to simulate the support of the surrounding geology on the coal seam in the natural environment. At the same time, the three-phase solenoid valve is connected to the variable exhaust pipe to directionally collect or guide the gas generated during the pyrolysis of the coal seam, so as to apply a directional force to change the direction of crack deformation, so as to observe the corresponding pyrolysis product gas and crack change parameters.

[0020] By opening the valve, external mud is injected to reinforce the joints of the crack plates, forming different support hardnesses to support the deformation of the crack plates to simulate the support strength of external geology.

[0021] Furthermore, in step 2, the area to be mined is first divided into a number of plots of uniform size, and the location coordinates of the injection wells, the location coordinates of the extraction wells and the distribution coordinates of the fractures are marked in the geological virtual model.

[0022] Beneficial effects: Classification and marking of plots facilitate subsequent search for injection wells, extraction wells and fracture distribution coordinates, so as to facilitate position adjustment and regulation.

[0023] Furthermore, the simulation devices are arranged in a linear straight line, and the experimental temperatures of adjacent simulation devices decrease successively.

[0024] Beneficial effects: By changing the experimental temperature to simulate the temperature decay of high-temperature carrier gas injected through the injection well under natural conditions, the corresponding fracture change parameters and pyrolysis product gases under experimental conditions can be obtained, providing experimental data for the in-situ pyrolysis of oil-rich coal underground in the actual process, so as to provide parameters for the subsequent selection of the location of extraction wells and reinforcement wells, and maintain the stability of underground geology.

[0025] Furthermore, condensed water is provided in the compression chamber, the condensed water is located on the side of the piston away from the regulating rod, and a pressure relief valve is connected between the compression chamber and the tank body.

[0026] Beneficial effect: By collecting the generated gas and adjusting the support strength of the pressure shaft on the crack plate, the condensed water can be compressed and discharged, simulating the interference of surrounding groundwater infiltration on coal seam pyrolysis or crack formation during crack formation, providing parameter basis for subsequent reinforcement.

[0027] Furthermore, coal seam composition parameters include coal seam sample parameters, coal seam gas composition parameters, surrounding geological parameters and groundwater distribution parameters; geological fracture parameters include basic fracture parameters and fracture depth coordinate information; pyrolysis atmosphere parameters include coal seam temperature data, coal seam thermal diffusion parameters and thermal conductivity parameters.

[0028] Beneficial effects: Confirmation through different parameters provides a basic control for the restoration of the environment in the simulation device. Simulation is performed by observing the fracture change parameters and pyrolysis product gases to provide basic data for subsequent extraction wells and reinforcement wells.

[0029] Furthermore, in step one, the extraction wells are arranged in a circular shape with the injection well as the center.

[0030] Beneficial effect: The arrangement is made based on the influence range of the injection wells for injecting heat-carrying fluid, so as to improve the effective use of the injection wells and thus ensure the utilization rate of thermal energy.

[0031] Furthermore, in step three, the simulated rock hardness corresponding to the crack size around the oil-rich coal sample at different locations is changed by adding high temperature resistant mud by replacing the tube, and the crack change parameters and pyrolysis product gases corresponding to different simulated rock hardness are obtained;

[0032] In step four, the rock formation hardness corresponding to the fracture distribution coordinates is obtained, and then the gas pressure data of the pyrolysis product gas corresponding to the simulated rock formation hardness corresponding to the rock formation hardness is obtained and compared with the set standard gas pressure data. When the gas pressure data of the pyrolysis product gas is greater than the standard gas pressure data, the fracture change parameters are compared with the geological fracture parameters to obtain the fracture expansion change range, and the reinforcement wells are arranged according to the fracture expansion range; then, the position coordinates of the extraction wells in the geological virtual model are adjusted based on the migration range of the pyrolysis product gas; when the gas pressure data of the pyrolysis product gas is less than the standard gas pressure data, safety marking is performed in the geological virtual model based on the fracture distribution coordinates.

[0033] Beneficial effect: By changing the hardness of the rock formation to simulate the effect of the hardness of the rock formation under natural conditions on the cracks, it is possible to choose whether to arrange reinforcement wells for reinforcement to protect the original geology from external damage.

[0034] Furthermore, in step four, when the position coordinates of the extraction well in the geological virtual model are adjusted based on the migration range of the pyrolysis product gas, the rock formation hardness corresponding to the fracture distribution coordinates is reinforced with the same rock formation hardness in the simulation device to obtain the maximum fracture change parameters in different directions, and the migration range of the pyrolysis product gas is set at the direction corresponding to the maximum fracture change parameter.

[0035] Beneficial effects: By simulating the pyrolysis process under the same rock hardness, the changes in the surrounding cracks can be obtained, providing a basic basis for the subsequent position adjustment of the extraction wells, so as to balance the underground gas pressure through the exploitation of the extraction wells, thereby reducing the impact on the surrounding geology during the underground in-situ conversion process.

[0036] Furthermore, an economic evaluation method for an underground in-situ conversion method of oil-rich coal, based on the above-mentioned economic evaluation method for underground in-situ conversion method of oil-rich coal, comprises the following steps: recording the pyrolysis product gases of different extraction wells, judging the trends of the pyrolysis product gases in different months, if the trend of the pyrolysis product gases of the extraction well is gradually rising, calculating the monthly profit based on the pyrolysis product gases, and merging the extraction wells and reinforced wells according to the migration range of the pyrolysis product gases; if the trend of the pyrolysis product gases of the extraction well is gradually decreasing, calculating the maintenance costs of the reinforced wells and the extraction wells, and adjusting the number of reinforced wells and extraction wells based on the monthly profit and maintenance costs at the current time.

[0037] Beneficial effects: Based on the changes in the production of pyrolysis product gas, adjustments are made through monthly profits, maintenance costs and migration range, and adjustments are made to reinforced wells and extraction wells to reduce corporate costs and improve corporate benefits.

[0038] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 It is a schematic flow diagram of an embodiment of the underground in-situ conversion method of oil-rich coal of the present invention;

[0040] Figure 2 It is a schematic diagram of a simulation device in an embodiment of the underground in-situ conversion method of oil-rich coal of the present invention;

[0041] Figure 3 for Figure 2 A cross-sectional view of

[0042] Figure 4 for Figure 3 An enlarged view of part A.

[0043] The figure marks in the drawings of the specification include: 1, tank body; 11, fixing block; 2, replacement pipe; 3, exhaust pipe; 31, three-phase solenoid valve; 4, crack plate; 41, rotating shaft; 42, clamping shaft; 5, pressurizing shaft; 51, liquid inlet pipe; 52, piston; 53, pressure relief valve; 54, adjusting rod; 6, electric heating tube. DETAILED DESCRIPTION

[0044] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0045] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0046] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0047] The following is further described in detail through specific implementation methods:

[0048] Embodiment 1:

[0049] As attached Figures 1 to 4As shown: An underground in-situ conversion method for oil-rich coal includes the following steps: Step 1, collecting geological data, pre-collecting and obtaining related geological data in the area to be mined, the geological data includes coal seam composition parameters, geological fracture parameters, pyrolysis atmosphere parameters, and the location coordinates of pre-set injection wells and extraction wells, and the extraction wells are arranged in a circular shape with the injection well as the center. Among them, the coal seam composition parameters include coal seam sample parameters, coal seam gas composition parameters, surrounding geological parameters and groundwater distribution parameters; geological fracture parameters include basic fracture parameters and fracture depth coordinate information; pyrolysis atmosphere parameters include coal seam temperature data, coal seam thermal diffusion parameters and thermal conductivity parameters.

[0050] Step 2: Establish a geological virtual model based on geological data, divide the area to be mined into several plots of the same size, mark the plots in the geological virtual model based on the location coordinates of the injection well and the extraction well, and add fracture distribution coordinates to the corresponding positions of the geological virtual model based on geological fracture parameters;

[0051] Step 3: Arrange simulation conditions for the oil-rich coal samples in the simulation device based on the pyrolysis atmosphere parameters, set the crack sizes of the oil-rich coal samples in different directions based on the geological fracture parameters, and then record the corresponding crack change parameters and pyrolysis product gases under the experimental conditions.

[0052] The simulation device includes a tank body 1, in which a plurality of crack plates 4 are arranged, and gaps are provided between adjacent crack plates 4; a plurality of electric heating tubes 6 for heating are provided in the crack plates 4; a stepped fixed block 11 is provided between adjacent crack plates 4, and a rotating shaft 41 is fixedly connected to the fixed block 11, the crack plate 4 rotates in cooperation with the rotating shaft 41, and a clamping shaft 42 is threadedly connected to one end of the crack plate 4 away from the rotating shaft 41, and the crack plate 4 is fixedly connected to the tank body 1 via the clamping shaft 42.

[0053] A pressure shaft 5 is provided between the tank body 1 and the crack plate 4, one end of the pressure shaft 5 is fixedly connected to the tank body 1, a compression chamber is opened in the pressure shaft 5, a piston 52 is slidably fitted in the compression chamber, an adjusting rod 54 is fixedly connected to one end of the piston 52, and the end of the adjusting rod 54 away from the piston 52 is hinged to the end of the crack plate 4 away from the rotating shaft 41; the end of the compression chamber close to the crack plate 4 is also connected to an exhaust pipe 3, the exhaust pipe 3 is a Y-shaped pipe, the other end of the exhaust pipe 3 is connected to the center of the crack plate 4, the other end of the exhaust pipe 3 is connected to the outside of the tank body 1, and the junction of the exhaust pipe 3 is connected to a three-phase solenoid valve 31; the three-phase solenoid valve 31 is electrically connected to a control panel (not shown in the figure); condensed water is also provided in the compression chamber, the condensed water is located on the side of the piston 52 away from the adjusting rod 54, and a pressure relief valve 53 is connected between the compression chamber and the tank body 1, and a liquid inlet pipe 51 is connected between the compression chamber and the outside of the tank body 1. The tank body 1 is connected with a plurality of replacement pipes 2 , the replacement pipes 2 are located between adjacent crack plates 4 , and the replacement pipes 2 are connected with valves.

[0054] For example, the generated gas is collected through the exhaust pipe 3, and the gas generated during the pyrolysis of the coal seam is collected or guided in a directional manner through the connection of the three-phase solenoid valve 31, so as to apply a directional force to change the direction of the crack deformation, so as to observe the corresponding pyrolysis product gas and crack change parameters. The gaps formed by different crack plates 4 simulate geological crack parameters, and the crack plates 4 are supported by the pressure shaft 5 to simulate the support of the surrounding geology to the coal seam under the natural environment.

[0055] The piston 52 is then pushed by gas to move so as to compress and discharge the condensed water, simulating the interference of surrounding groundwater infiltration on coal seam pyrolysis or crack formation during crack formation, thereby providing parameter basis for subsequent reinforcement.

[0056] Then, by replacing tube 2 and adding high-temperature resistant mud, the simulated rock hardness corresponding to the crack size in different directions of the oil-rich coal sample is changed to obtain the crack change parameters and pyrolysis product gases corresponding to different simulated rock hardnesses; high-temperature resistant mud is a prior art and will not be described in detail in this actual example.

[0057] Step 4: Based on the fracture distribution coordinates of different geological fracture parameters in the geological virtual model, the fracture change parameters and pyrolysis product gases corresponding to the experimental conditions are obtained, and then the rock formation hardness corresponding to the fracture distribution coordinates is obtained, and then the gas pressure data of the pyrolysis product gas corresponding to the simulated rock formation hardness corresponding to the rock formation hardness is obtained and compared with the set standard gas pressure data. When the gas pressure data of the pyrolysis product gas is greater than the standard gas pressure data, the fracture change parameters are compared with the geological fracture parameters to obtain the fracture expansion change range, and the reinforcement wells are arranged according to the fracture expansion range; then, based on the migration range of the pyrolysis product gas, the position coordinates of the extraction wells in the geological virtual model are adjusted, and based on the rock formation hardness corresponding to the fracture distribution coordinates, the same rock formation hardness is used for reinforcement in the simulation device, and the maximum fracture change parameters in different directions are obtained, and the migration range of the pyrolysis product gas is set at the direction corresponding to the maximum fracture change parameter; when the gas pressure data of the pyrolysis product gas is less than the standard gas pressure data, safety marking is performed in the geological virtual model based on the fracture distribution coordinates.

[0058] For example, the pyrolysis process is simulated under the same rock hardness to obtain the changes in the surrounding cracks, providing a basis for the subsequent position adjustment of the extraction wells, so as to balance the underground gas pressure through the extraction of the extraction wells, thereby reducing the impact of the underground in-situ transformation process on the surrounding geology. At the same time, by changing the rock hardness to simulate the impact of the rock hardness under natural conditions on the cracks, it is possible to choose whether to arrange reinforcement wells for reinforcement to protect the original geology from external damage.

[0059] For example, by adjusting the layout of reinforcement wells or extraction wells, the pressure on surrounding strata during in-situ pyrolysis of oil-rich coal can be reduced, and the original geology can be maintained from being affected by external changes. At the same time, based on the changing parameters of geological fractures, the possible diffusion of fractures can be understood to determine the geological consolidation points to prevent the pyrolysis product gases from diffusing to the surrounding areas, which makes it inconvenient to collect the gases later and easily causes pollution to the original groundwater. By adjusting the position of the extraction wells to control the coal seam pressure in a timely manner and maintain a sufficiently high pressure to extract the gases, the extraction wells can also be used as the location to reinforce geological fractures to reduce the subsequent impact of the fractures.

[0060] An economic evaluation method for an underground in-situ conversion method of oil-rich coal, according to the above-mentioned economic evaluation method for underground in-situ conversion method of oil-rich coal, comprises the following steps: recording the pyrolysis product gases of different extraction wells, judging the trends of the pyrolysis product gases in different months, if the trend of the pyrolysis product gases of the extraction well is gradually rising, calculating the monthly profit based on the pyrolysis product gases, and merging the extraction wells and reinforced wells according to the migration range of the pyrolysis product gases; if the trend of the pyrolysis product gases of the extraction well is gradually falling, calculating the maintenance costs of the reinforced wells and the extraction wells, and adjusting the number of reinforced wells and extraction wells based on the monthly profit and maintenance costs at the current time.

[0061] For example, based on the changes in the production of pyrolysis product gas, adjustments are made to the reinforced wells and extraction wells through monthly profits, maintenance costs and migration range to reduce corporate costs and improve corporate benefits.

[0062] Embodiment 2:

[0063] The difference from Example 1 is that the simulation devices are arranged in a linear straight line, and the experimental temperatures of adjacent simulation devices decrease successively.

[0064] For example, since the injection of high-temperature carrier gas through injection wells under natural conditions will show temperature attenuation, the corresponding fracture change parameters and pyrolysis product gases under experimental conditions can be obtained by changing the experimental temperature, providing experimental data for the in-situ pyrolysis of oil-rich coal underground in the actual process, so as to provide parameters for the subsequent selection of the locations of extraction wells and reinforcement wells and maintain the stability of underground geology.

[0065] Obviously, the above embodiments are merely examples for the purpose of clear explanation, and are not intended to limit the implementation methods. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is not necessary and impossible to list all the implementation methods here. The obvious changes or modifications derived therefrom are still within the scope of protection of the invention.

Claims

1. A method for underground in-situ conversion of oil-rich coal, characterized in that: The method comprises the following steps: step 1, collecting geological data, pre-collecting and obtaining related geological data in the area to be mined, wherein the geological data include coal seam composition parameters, geological fracture parameters, pyrolysis atmosphere parameters, and the location coordinates of the preset injection well and extraction well; Step 2: Establish a geological virtual model based on geological data, then mark the geological virtual model based on the location coordinates of the injection well and the extraction well, and add fracture distribution coordinates to the corresponding positions of the geological virtual model based on geological fracture parameters; Step 3: Arrange the simulation conditions of the oil-rich coal sample in the simulation device based on the pyrolysis atmosphere parameters, set the crack sizes of the oil-rich coal sample in different directions based on the geological crack parameters, and then record the corresponding crack change parameters and pyrolysis product gases under the experimental conditions; Step 4: Based on the fracture distribution coordinates of different geological fracture parameters in the geological virtual model, obtain the fracture change parameters and pyrolysis product gases corresponding to the experimental conditions, compare the fracture change parameters with the geological fracture parameters, obtain the fracture expansion range, and arrange reinforcement wells according to the fracture expansion range; then adjust the position coordinates of the extraction wells in the geological virtual model based on the migration range of the pyrolysis product gases.

2. The underground in-situ conversion method of oil-rich coal according to claim 1, characterized in that: The simulation device comprises a tank body (1), wherein a plurality of crack plates (4) are arranged in the tank body (1), and gaps are provided between adjacent crack plates (4); and a plurality of electric heating tubes (6) for heating are provided in the crack plates (4); A stepped fixing block (11) is provided between adjacent slit plates (4), a rotating shaft (41) is fixedly connected to the fixing block (11), the slit plate (4) and the rotating shaft (41) are rotatably matched, and a clamping shaft (42) is threadedly connected to one end of the slit plate (4) away from the rotating shaft (41), and the slit plate (4) is fixedly connected to the tank body (1) via the clamping shaft (42); A pressure shaft (5) is provided between the tank body (1) and the crack plate (4), one end of the pressure shaft (5) is fixedly connected to the tank body (1), a compression chamber is provided in the pressure shaft (5), a piston (52) is slidably fitted in the compression chamber, one end of the piston (52) is fixedly connected to an adjusting rod (54), an end of the adjusting rod (54) away from the piston (52) is hinged to an end of the crack plate (4) away from the rotating shaft (41); an end of the compression chamber close to the crack plate (4) is also connected to an exhaust pipe (3), the exhaust pipe (3) is a Y-shaped pipe, the other end of the exhaust pipe (3) is connected to the center of the crack plate (4), the other end of the exhaust pipe (3) is connected to the outside of the tank body (1), and a three-phase solenoid valve (31) is connected at the intersection of the exhaust pipe (3); the three-phase solenoid valve (31) is electrically connected to a control panel; The tank body (1) is connected to a plurality of replacement pipes (2), the replacement pipes (2) are located between adjacent crack plates (4), and the replacement pipes (2) are connected to valves.

3. The underground in-situ conversion method of oil-rich coal according to claim 2, characterized in that: In step 2, the area to be mined is first divided into several plots of uniform size, and the location coordinates of the injection wells, the location coordinates of the extraction wells and the distribution coordinates of the fractures are marked in the geological virtual model.

4. The underground in-situ conversion method of oil-rich coal according to claim 3, characterized in that: The simulation devices are arranged in a linear straight line, and the experimental temperatures of adjacent simulation devices decrease successively.

5. The underground in-situ conversion method of oil-rich coal according to claim 4, characterized in that: Condensed water is also provided in the compression chamber, and the condensed water is located on the side of the piston (52) away from the regulating rod (54), and a pressure relief valve (53) is connected between the compression chamber and the tank body (1).

6. The underground in-situ conversion method of oil-rich coal according to claim 5, characterized in that: Coal seam composition parameters include coal seam sample parameters, coal seam gas composition parameters, surrounding geological parameters and groundwater distribution parameters; geological fracture parameters include basic fracture parameters and fracture depth coordinate information; pyrolysis atmosphere parameters include coal seam temperature data, coal seam thermal diffusion parameters and thermal conductivity parameters.

7. The underground in-situ conversion method of oil-rich coal according to claim 6, characterized in that: In step one, the extraction wells are arranged in a circular shape with the injection well as the center.

8. The underground in-situ conversion method of oil-rich coal according to claim 7, characterized in that: In step three, the simulated rock hardness corresponding to the size of cracks in different directions of the oil-rich coal sample is changed by adding high temperature resistant mud by replacing the tube (2), and the crack change parameters and pyrolysis product gases corresponding to different simulated rock hardness are obtained; In step four, the rock formation hardness corresponding to the fracture distribution coordinates is obtained, and then the gas pressure data of the pyrolysis product gas corresponding to the simulated rock formation hardness corresponding to the rock formation hardness is obtained and compared with the set standard gas pressure data. When the gas pressure data of the pyrolysis product gas is greater than the standard gas pressure data, the fracture change parameters are compared with the geological fracture parameters to obtain the fracture expansion change range, and the reinforcement wells are arranged according to the fracture expansion range; then, the position coordinates of the extraction wells in the geological virtual model are adjusted based on the migration range of the pyrolysis product gas; when the gas pressure data of the pyrolysis product gas is less than the standard gas pressure data, safety marking is performed in the geological virtual model based on the fracture distribution coordinates.

9. The underground in-situ conversion method of oil-rich coal according to claim 8, characterized in that: In step four, when the position coordinates of the extraction well in the geological virtual model are adjusted based on the migration range of the pyrolysis product gas, the rock formation hardness corresponding to the fracture distribution coordinates is reinforced with the same rock formation hardness in the simulation device to obtain the maximum fracture change parameters in different directions, and the migration range of the pyrolysis product gas is set at the direction corresponding to the maximum fracture change parameter.

10. An economic evaluation method for an underground in-situ conversion method of oil-rich coal, characterized in that: The economic evaluation method for the underground in-situ conversion method of oil-rich coal according to any one of claims 1 to 9 comprises the following steps: recording the pyrolysis product gases of different extraction wells, judging the trends of the pyrolysis product gases in different months, and if the trend of the pyrolysis product gases of the extraction well is gradually rising, calculating the monthly profit based on the pyrolysis product gases, and merging the extraction wells and reinforced wells according to the migration range of the pyrolysis product gases; if the trend of the pyrolysis product gases of the extraction well is gradually falling, calculating the maintenance costs of the reinforced wells and the extraction wells, and adjusting the number of reinforced wells and extraction wells based on the monthly profit and maintenance costs at the current time.

Images