Positive-temperature electromagnetic variable-frequency induction underground heating device for in-situ conversion of hydrocarbon generation of oil shale

Abstract

The invention belongs to the technical field of petrochemical engineering, and particularly relates to a positive-temperature electromagnetic variable-frequency induction underground heating device for in-situ conversion of oil shale hydrocarbon generation, which comprises an electromagnetic frequency converter, a temperature monitoring system and an underground heating assembly, the underground heating assembly comprises a heater; a pair of mounting rings is fixedly connected to the interior of the heater; an induction coil is fixedly connected between the mounting rings; the induction coil is made of a barium titanate composite material and a tungsten alloy material; an iron core is arranged in the induction coil; and the top of the heater is fixedly connected with a hollow rod. According to the device, by adopting an efficient electromagnetic induction technology and an optimized heating control strategy, underground in-situ rapid conversion of the oil shale is realized, the thermal cracking efficiency of the oil shale can be improved, the environmental influence and the operation cost are greatly reduced, and the safety risk caused by fuel leakage is avoided.

Description

Technical Field

[0001] The invention belongs to the technical field of petrochemical industry, and in particular to a positive temperature electromagnetic variable frequency induction underground heating device for in-situ conversion of oil shale hydrocarbon generation. Background Art

[0002] Oil shale is a sedimentary rock containing recoverable organic matter. Its main component is rock containing a large amount of organic matter. These organic matter can be converted into liquid petroleum or gas through pyrolysis (heating to a certain temperature) under specific conditions. As a potential source of energy, oil shale has abundant resource reserves, but its mining and extraction technology still faces challenges of high costs and environmental issues. Oil shale pyrolysis is divided into above-ground pyrolysis and underground pyrolysis. Underground pyrolysis is also called in-situ conversion, which means that the oil shale buried underground is directly heated and distilled underground without mining, and then the produced oil and gas are exported to the ground. In-situ conversion has the advantages of high resource utilization, small environmental impact, and high economic benefits compared to above-ground pyrolysis.

[0003] A Chinese patent application CN104612642B discloses a combustion heating system for oil shale formations in a well. The key points of its technical solution are: including ground monitoring and control system, well combustion and exhaust gas countercurrent heat exchange system, external fluid injection pipe and external casing. When this technology is in operation, the fuel passes through the burner casing and burns in a sealed combustion chamber without direct contact with the external formation environment downhole. This technology can be used as a heating body to directly heat the downhole formation, or it can heat an external fluid medium downhole and then perform permeation heat and mass transfer on the formation, which can realize hot gas mining, superheated steam mining, and near / supercritical fluid mining of the formation. This technology can be used for in-situ conversion and mining of organic matter in oil shale reservoirs.

[0004] However, the above technologies often have the following defects: the heating system has a relatively complex structure, and its heating process relies on the combustion of fuel, which not only has low thermal efficiency and high energy consumption, but also has the risk of leakage during the transportation and combustion of fuel. It has high requirements on the quality of equipment and is prone to safety accidents such as explosion and poisoning. In addition, if the exhaust gas formed after combustion is not properly handled, there will also be problems of environmental pollution.

[0005] To this end, the present invention provides a positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation. Summary of the invention

[0006] In order to make up for the deficiencies of the prior art, at least one technical problem raised in the background technology is solved.

[0007] The technical solution adopted by the present invention to solve the technical problem is: the positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation described in the present invention comprises an electromagnetic frequency converter, a temperature monitoring system and an underground heating component;

[0008] The electromagnetic frequency converter can adjust the output frequency to adapt to different formation conditions;

[0009] The temperature monitoring system monitors the heating temperature in real time to ensure that the heating process is carried out at the optimal temperature;

[0010] The underground heating assembly includes a heater; a pair of mounting rings are fixedly connected inside the heater; an induction coil is fixedly connected between the mounting rings; the induction coil is made of barium titanate composite material and tungsten alloy material; a columnar iron core is arranged inside the induction coil; and a hollow rod is fixedly connected to the top of the heater.

[0011] Preferably, a hollow conical cover is provided inside the heater at a position above the iron core; a group of spray holes are evenly distributed on the inner side of the conical cover; a water pipe is provided inside the hollow rod, and the lower end of the water pipe extends into the interior of the heater and is interconnected with the conical cover; a group of release holes are evenly distributed on the surface of the heater.

[0012] Preferably, a blocking block is provided on the outer side of the top of the hollow rod.

[0013] Preferably, a pressure relief port is provided at the top of the hollow rod below the blocking block; a pressure relief valve is provided inside the pressure relief port.

[0014] Preferably, an air guide plate is provided between the outer side of the water pipe and the inner side of the hollow rod, and the air guide plate is located above the pressure relief port; the air guide plate is designed to be in a spiral rising shape.

[0015] Preferably, a cavity is provided inside the iron core; the water pipe and the cavity are connected to each other via a shunt pipe; and a group of guide holes are evenly distributed on the surface of the iron core.

[0016] Preferably, a group of water blocking plates are evenly distributed inside the cavity, and the water blocking plates are recessed downwards; the water blocking plates are made of good thermal conductive material; a group of through holes are evenly distributed on the surface of the water blocking plates, and the through holes of adjacent water blocking plates are staggered with each other.

[0017] Preferably, a group of fins are evenly distributed on the upper side of the water blocking plate; the fins are made of good thermal conductive material; and an elastic member is fixedly connected between the fins and the water blocking plate.

[0018] Preferably, a group of annular water stop flaps are evenly distributed on the surface of the iron core; the water stop flaps are made of good thermal conductive material; there is an angle between the water stop flap and the iron core; an annular water guide plate is fixedly connected to the outside of the water stop flap; the water guide plate covers the top of the water stop flap, and there is a gap between the water guide plate and the water stop flap.

[0019] Preferably, a water-containing cap is fixedly connected to the lower side of the iron core; and there is a gap between the water-containing cap and the bottom of the iron core.

[0020] The beneficial effects of the present invention are as follows:

[0021] 1. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation described in the present invention uses a hollow rod to lower the heater to the position of the oil shale inside the working well, and generates an induced current and a large amount of heat inside the iron core by energizing the induction coil, thereby heating the surrounding oil shale. The device adopts efficient electromagnetic induction technology and optimized heating control strategy to achieve rapid in-situ conversion of oil shale underground, which can improve the thermal cracking efficiency of oil shale, greatly reduce environmental impact and operating costs, and avoid safety risks caused by fuel leakage.

[0022] 2. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation described in the present invention connects a water pipe to an external water source. When working, water flows along the water pipe into the interior of the conical cover and is sprayed toward the top of the iron core through the spray holes on the inner side of the conical cover. After the water contacts the surface of the iron core, it is quickly evaporated and vaporized by the heat thereof to generate a large amount of water vapor. After the water vapor escapes through the release holes on the surface of the heater, it heats the oil shale, thereby improving the heating uniformity of the oil shale. In addition, the high-pressure water vapor is conducive to fracturing the surrounding rock and soil, so that many small cracks are generated in the oil shale, and then the water vapor can enter the interior of the oil shale along these cracks for heating, further improving the cracking efficiency of the oil shale and facilitating the collection of oil and gas resources.

[0023] 3. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation described in the present invention is provided with a pressure relief port and a pressure relief valve. When the pressure inside the working well reaches a certain threshold, the pressure relief valve automatically opens, and the gas enters the hollow rod through the pressure relief port and flows upward to the outside of the well, thereby relieving the pressure in the working well to prevent the risk of explosion due to excessive pressure. In addition, the high-temperature water vapor can contact the water pipe during the upward flow of the hollow rod, and the direction is opposite to the water flow transported inside the water pipe, thereby preheating the water inside the water pipe and heating it to a certain temperature. Then, the water can be quickly vaporized when it contacts the iron core, thereby improving the efficiency of water vapor generation. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below in conjunction with the accompanying drawings.

[0025] Figure 1 is a stereogram of the present invention;

[0026] Figure 2 yes Figure 1 A partial enlarged view of the middle part;

[0027] Figure 3 It is a structural schematic diagram of the induction coil in the present invention;

[0028] Figure 4 yes Figure 3 A partial enlarged view of point B in the middle;

[0029] Figure 5 It is a structural schematic diagram of the iron core in the present invention;

[0030] Figure 6 is a cross-sectional view of the present invention;

[0031] Figure 7 yes Figure 6 A partial enlarged view of point C in the middle;

[0032] Figure 8 yes Figure 7 A partial enlarged view of point D in the middle.

[0033] In the figure: working well 1, heater 2, mounting ring 3, induction coil 4, iron core 5, hollow rod 6, conical cover 7, spray hole 8, water pipe 9, release hole 10, blocking block 11, pressure relief port 12, air guide plate 13, cavity 14, diverter pipe 15, guide hole 16, water blocking plate 17, through hole 18, fin 19, elastic member 20, water stop flap 21, water guide plate 22, water holding cap 23. DETAILED DESCRIPTION

[0034] In order to make the technical means, creative features, objectives and effects achieved by the present invention easy to understand, the present invention is further explained below in conjunction with specific implementation methods.

[0035] like Figures 1 to 8 As shown, the positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to the present invention comprises an electromagnetic frequency converter, a temperature monitoring system and an underground heating component;

[0036] The electromagnetic frequency converter can adjust the output frequency to adapt to different formation conditions;

[0037] The temperature monitoring system monitors the heating temperature in real time to ensure that the heating process is carried out at the optimal temperature. The temperature monitoring system uses a positive temperature coefficient thermistor (PTC) material to automatically adjust the heating power without the need for an external temperature control system;

[0038] The underground heating assembly includes a heater 2; a pair of mounting rings 3 are fixedly connected inside the heater 2; an induction coil 4 is fixedly connected between the mounting rings 3; the induction coil 4 is made of barium titanate composite material and tungsten alloy material to achieve rapid heating and high heating efficiency; a columnar iron core 5 is arranged inside the induction coil 4; a hollow rod 6 is fixedly connected to the top of the heater 2.

[0039] The structure of the oil shale in-situ heating system in the prior art is relatively complex, and its heating process relies on the combustion of fuel. It not only has low thermal efficiency and high energy consumption, but also has the risk of leakage during the transportation and combustion of fuel. It has high requirements on the quality of equipment and is prone to safety accidents such as explosion and poisoning. In addition, if the exhaust gas formed after combustion is not properly handled, there will also be environmental pollution problems.

[0040] When the present invention is in use, the heater 2 is lowered to the oil shale position inside the working well 1 by using the hollow rod 6. By energizing the induction coil 4, an induced current is generated inside the iron core 5 and a large amount of heat is generated, thereby heating the surrounding oil shale. The device adopts efficient electromagnetic induction technology and optimized heating control strategy to achieve rapid in-situ conversion of oil shale underground, which can improve the thermal cracking efficiency of oil shale, greatly reduce environmental impact and operating costs, and avoid safety risks caused by fuel leakage.

[0041] A hollow conical cover 7 is provided inside the heater 2 at the position above the iron core 5; a group of spray holes 8 are evenly distributed inside the conical cover 7; a water pipe 9 is provided inside the hollow rod 6, and the lower end of the water pipe 9 extends to the inside of the heater 2 and is connected with the conical cover 7; a group of release holes 10 are evenly distributed on the surface of the heater 2. By connecting the water pipe 9 to an external water source, water flows along the water pipe 9 into the conical cover 7 during operation, and sprays toward the top of the iron core 5 through the spray holes 8 inside the conical cover 7. After the water contacts the surface of the iron core 5, it is quickly evaporated and vaporized by the heat thereof, generating a large amount of water vapor. After the water vapor escapes through the release holes 10 on the surface of the heater 2, it heats the oil shale, thereby improving the heating uniformity of the oil shale, and the high-pressure water vapor is conducive to fracturing the surrounding rock and soil, so that the oil shale has many small cracks, and then the water vapor can enter the oil shale along these cracks to heat it, further improving the cracking efficiency of the oil shale and facilitating the collection of oil and gas resources.

[0042] As a preferred embodiment of the present invention, a sealing block 11 is provided on the outer side of the top of the hollow rod 6. After the heater 2 is lowered to a suitable position, the sealing block 11 is sleeved on the outer side of the hollow rod 6 and inserted into the working well 1, thereby sealing the working well 1. On the one hand, it can reduce the heat loss to the outside during the heating process, and on the other hand, it can enable the water vapor generated inside the working well 1 to quickly form a high-pressure environment, thereby improving the heating and fracturing efficiency of the oil shale.

[0043] As a preferred embodiment of the present invention, a pressure relief port 12 is provided at the top of the hollow rod 6 below the blocking block 11; a pressure relief valve is provided inside the pressure relief port 12. By providing the pressure relief port 12 and the pressure relief valve, when the pressure inside the working well 1 reaches a certain threshold, the pressure relief valve automatically opens, and the gas enters the hollow rod 6 through the pressure relief port 12 and flows upward to the outside of the well, thereby relieving the pressure of the working well 1 to prevent the risk of explosion due to excessive pressure. In addition, the high-temperature water vapor can contact the water pipe 9 during the upward flow of the hollow rod 6, and the direction is opposite to the water flow transported inside the water pipe 9, thereby preheating the water inside the water pipe 9 to a certain temperature, and then the water can be quickly vaporized when it contacts the iron core 5, thereby improving the efficiency of water vapor generation.

[0044] An air guide sheet 13 is provided between the outer side of the water pipe 9 and the inner side of the hollow rod 6, and the air guide sheet 13 is located above the pressure relief port 12; the air guide sheet 13 is designed to be in a spiral shape. The air guide sheet 13 is provided to guide the high-temperature water vapor inside the hollow rod 6, so that the water vapor can spirally rise outside the water pipe 9 when flowing upward, thereby extending the contact time between the high-temperature water vapor and the water pipe 9, improving the heating uniformity of the water flow in the water pipe 9, and allowing the water flow to fully absorb heat from the water vapor.

[0045] As a preferred embodiment of the present invention, a cavity 14 is provided inside the iron core 5; the water pipe 9 and the cavity 14 are connected to each other through a shunt pipe 15; and a group of guide holes 16 are evenly distributed on the surface of the iron core 5. When the water flows along the water pipe 9 into the conical cover 7, it will also simultaneously enter the cavity 14 of the iron core 5 through the shunt pipe 15, and then the heat generated inside the iron core 5 can heat and vaporize the water in the cavity 14, and the generated water vapor escapes outward through the guide holes 16, so that water vapor can be generated on the outer surface and inside of the iron core 5, so as to increase the output and generation rate of water vapor.

[0046] A group of water blocking plates 17 are evenly distributed inside the cavity 14, and the water blocking plates 17 are concave downward; the water blocking plates 17 are made of good heat conductive material; a group of through holes 18 are evenly distributed on the surface of the water blocking plates 17, and the through holes 18 of adjacent water blocking plates 17 are mutually dislocated. By providing multiple water blocking plates 17, after the water flows into the cavity 14 through the shunt pipe 15, it can be blocked by the multiple water blocking plates 17 in sequence, and the water flows downward through the mutually dislocated through holes 18 in sequence, thereby extending the flow path of the water flow, allowing the water to be distributed on the surfaces of the multiple water blocking plates 17, so that the water is more dispersed inside the cavity 14, and the water is heated by the heat-conducting water blocking plates 17 respectively, thereby enhancing the heating and boiling effect of the iron core 5 on the water and improving the heating degree of the oil shale.

[0047] A group of fins 19 are evenly distributed on the upper side of the water blocking plate 17; the fins 19 are made of good heat-conducting material; and an elastic member 20 is fixedly connected between the fins 19 and the water blocking plate 17. By providing the heat-conducting fins 19, the heat generated inside the iron core 5 can be conducted to the multiple fins 19 along the water blocking plate 17, and the contact area between the fins 19 and the water is further increased by using the fins 19, thereby improving the heating efficiency of the water, and by providing the elastic member 20, the boiling effect of the water on the surface of the water blocking plate 17 can cause the fins 19 to shake, thereby further disturbing and rolling the water, thereby improving the heat exchange efficiency.

[0048] As a preferred embodiment of the present invention, a group of annular water stop flaps 21 are evenly distributed on the surface of the iron core 5; the water stop flaps 21 are made of benign thermal conductive material; there is an angle between the water stop flap 21 and the iron core 5; an annular water guide plate 22 is fixedly connected to the outside of the water stop flap 21; the water guide plate 22 covers the top of the water stop flap 21, and there is a gap between the water guide plate 22 and the water stop flap 21. When the water inside the cavity 14 boils, it is easy to splash outward through the guide hole 16. By setting the water stop flap 21, the water splashing outward and the water dripping from the outer surface of the top of the iron core 5 can be blocked by multiple water stop flaps 21, thereby reducing the falling speed of water on the surface of the iron core 5, so that the water is fully heated by the iron core 5, and the water can be stored between the inner side of the water stop flap 21 and the iron core 5 during the falling process. The iron core 5 and the heat-conducting water stop flap 21 are used to further heat and vaporize the water. When the water between the water stop flap 21 and the iron core 5 is full and flows outward, the water guide plate 22 can be used to guide the water flow, so that the water can flow along the gap between the water stop flap 21 and the water guide plate 22 to the outside of the water stop flap 21 and the surface of the iron core 5 and continue to be heated, thereby preventing the problem that the water flow is difficult to contact the iron core 5 and cannot be heated after falling along the edge of the water stop flap 21.

[0049] As a preferred embodiment of the present invention, a water-containing cap 23 is fixedly connected to the lower side of the iron core 5; there is a gap between the water-containing cap 23 and the bottom of the iron core 5. By providing the water-containing cap 23, when the water flow has not been vaporized after passing through a plurality of water-stopping flaps 21 on the outer side of the iron core 5 in sequence, the remaining water can fall into the water-containing cap 23 for collection, and the collected water can be further heated and vaporized at the bottom of the iron core 5, thereby improving the utilization of water resources, making it fully form water vapor, and increasing the conversion rate of water from liquid to gas.

[0050] Working principle: The heater 2 is lowered to the oil shale position inside the working well 1 by using the hollow rod 6. By energizing the induction coil 4, an induced current is generated inside the iron core 5 and a large amount of heat is generated, thereby heating the surrounding oil shale. The device uses efficient electromagnetic induction technology and optimized heating control strategy to achieve rapid in-situ conversion of oil shale underground, which can improve the thermal cracking efficiency of oil shale, greatly reduce environmental impact and operating costs, and avoid safety risks caused by fuel leakage; by connecting the water pipe 9 to an external water source, water flows along the water pipe 9 during operation. The water enters the interior of the conical cover 7 and is sprayed toward the top of the iron core 5 through the spray holes 8 on the inner side of the conical cover 7. After the water contacts the surface of the iron core 5, it is quickly evaporated and vaporized by the heat thereof, generating a large amount of water vapor. The water vapor escapes through the release holes 10 on the surface of the heater 2 to heat the oil shale, thereby improving the heating uniformity of the oil shale. The high-pressure water vapor is conducive to fracturing the surrounding rock and soil, so that many small cracks are generated in the oil shale, and then the water vapor can enter the oil shale along these cracks to heat it, further improving the cracking efficiency of the oil shale and facilitating the collection of oil and gas resources.

[0051] By setting the pressure relief port 12 and the pressure relief valve, when the pressure inside the working well 1 reaches a certain threshold, the pressure relief valve automatically opens, and the gas enters the hollow rod 6 through the pressure relief port 12 and flows upward to the outside of the well, thereby relieving the pressure of the working well 1 to prevent the risk of explosion due to excessive pressure. In addition, the high-temperature water vapor can contact the water pipe 9 during the upward flow of the hollow rod 6, and the direction is opposite to the water flow transported inside the water pipe 9, thereby preheating the water inside the water pipe 9 to a certain temperature, and then the water can be quickly vaporized when it contacts the iron core 5, thereby improving the efficiency of water vapor generation; by setting the air guide sheet 13 to guide the high-temperature water vapor inside the hollow rod 6, the water vapor can rise in a spiral shape outside the water pipe 9 when flowing upward, thereby extending the contact time between the high-temperature water vapor and the water pipe 9, improving the heating uniformity of the water flow in the water pipe 9, and allowing the water flow to fully absorb heat from the water vapor;

[0052] When the water flows along the water pipe 9 into the conical cover 7, it will also simultaneously enter the cavity 14 of the iron core 5 through the shunt pipe 15, and then the heat generated inside the iron core 5 can heat and vaporize the water in the cavity 14, and the generated water vapor escapes outward through the guide hole 16, so that water vapor can be generated on the outer surface and inside of the iron core 5, so as to increase the yield and generation rate of water vapor; by providing a plurality of water blocking plates 17, after the water flows through the shunt pipe 15 into the cavity 14, it can be blocked by the plurality of water blocking plates 17 in sequence, and the water flows downward in sequence through the mutually staggered through holes 18, thereby extending the flow path of the water flow and allowing the water to be distributed in The surfaces of the multiple water-blocking plates 17 make the water more dispersed inside the cavity 14, and the water is heated by the heat-conducting water-blocking plates 17, thereby enhancing the heating and boiling effect of the iron core 5 on the water and improving the degree of heating of the oil shale; by providing the heat-conducting fins 19, the heat generated inside the iron core 5 can be conducted to the multiple fins 19 along the water-blocking plates 17, and the contact area between the fins 19 and the water is further increased by using the fins 19, thereby improving the heating efficiency of the water; and by providing the elastic member 20, the boiling effect of the water on the surface of the water-blocking plate 17 can cause the fins 19 to shake, thereby further disturbing and rolling the water, thereby improving the heat exchange efficiency;

[0053] When the water inside the cavity 14 is boiling, it is easy to splash outward through the guide hole 16. By setting the water stop flap 21, the water splashing outward and the water pouring down from the outer surface of the top of the iron core 5 can be blocked by multiple water stop flaps 21, thereby reducing the falling speed of the water on the surface of the iron core 5, so that the water is fully heated by the iron core 5, and the water can be stored between the inner side of the water stop flap 21 and the iron core 5 during the falling process. The iron core 5 and the heat-conducting water stop flap 21 are used to further heat and vaporize the water. When the water between the water stop flap 21 and the iron core 5 is full and flows outward, the water guide sheet 22 can be used to guide the water flow, so that the water can The water can flow along the gap between the water stop flap 21 and the water guide plate 22 to the outside of the water stop flap 21 and the surface of the iron core 5 and continue to be heated, thereby preventing the problem that the water flow is difficult to contact with the iron core 5 and cannot be heated after falling along the edge of the water stop flap 21; by setting the water holding cap 23, when the water flow has not been vaporized after passing through multiple water stop flaps 21 on the outside of the iron core 5 in sequence, the remaining water can fall into the water holding cap 23 for collection, and the collected water is subsequently further heated and vaporized by using the bottom of the iron core 5, thereby improving the utilization of water resources, making it fully form water vapor, and increasing the conversion rate of water from liquid to gas.

[0054] The above-mentioned front, back, left, right, top and bottom are all based on the figures in the specification. Figure 1 As a benchmark, according to the person's observation perspective, the side of the device facing the observer is defined as the front, the left side of the observer is defined as the left, and so on.

[0055] In the description of the present invention, it should be understood that the terms "center", "longitudinal", "lateral", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying 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 should not be understood as limiting the scope of protection of the present invention.

[0056] The above shows and describes the basic principles, main features and advantages of the present invention. It should be understood by those skilled in the art that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation, characterized by: Includes electromagnetic inverter, temperature monitoring system and underground heating components; The electromagnetic frequency converter can adjust the output frequency to adapt to different formation conditions; The temperature monitoring system monitors the heating temperature in real time to ensure that the heating process is carried out at the optimal temperature; The underground heating assembly comprises a heater (2); a pair of mounting rings (3) are fixedly connected inside the heater (2); an induction coil (4) is fixedly connected between the mounting rings (3); the induction coil (4) is made of a barium titanate composite material and a tungsten alloy material; a columnar iron core (5) is arranged inside the induction coil (4); and a hollow rod (6) is fixedly connected to the top of the heater (2).

2. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 1 is characterized by: A hollow conical cover (7) is arranged inside the heater (2) at a position above the iron core (5); a group of spray holes (8) are evenly distributed inside the conical cover (7); a water pipe (9) is arranged inside the hollow rod (6), and the lower end of the water pipe (9) extends into the interior of the heater (2) and is connected to the conical cover (7); and a group of release holes (10) are evenly distributed on the surface of the heater (2).

3. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 2 is characterized by: A blocking block (11) is arranged on the outer side of the top of the hollow rod (6).

4. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 3 is characterized by: A pressure relief port (12) is provided at the top of the hollow rod (6) below the blocking block (11); a pressure relief valve is provided inside the pressure relief port (12).

5. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 4 is characterized by: An air guide plate (13) is provided between the outer side of the water pipe (9) and the inner side of the hollow rod (6), and the air guide plate (13) is located above the pressure relief port (12); the air guide plate (13) is designed to be in a spiral rising shape.

6. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 2 is characterized by: A cavity (14) is provided inside the iron core (5); the water pipe (9) and the cavity (14) are connected to each other via a shunt pipe (15); and a group of guide holes (16) are evenly distributed on the surface of the iron core (5).

7. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 6 is characterized by: A group of water blocking plates (17) are evenly distributed inside the cavity (14), and the water blocking plates (17) are concave downwards; the water blocking plates (17) are made of good thermal conductive material; a group of through holes (18) are evenly distributed on the surface of the water blocking plates (17), and the through holes (18) of adjacent water blocking plates (17) are staggered with each other.

8. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 7 is characterized by: A group of fins (19) are evenly distributed on the upper side of the water blocking plate (17); the fins (19) are made of a good thermal conductive material; and an elastic member (20) is fixedly connected between the fins (19) and the water blocking plate (17).

9. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 2 is characterized by: A group of annular water stop flaps (21) are evenly distributed on the surface of the iron core (5); the water stop flaps (21) are made of good heat conductive material; an angle exists between the water stop flaps (21) and the iron core (5); an annular water guide plate (22) is fixedly connected to the outside of the water stop flap (21); the water guide plate (22) covers the top of the water stop flap (21), and a gap exists between the water guide plate (22) and the water stop flap (21).

10. The positive temperature electromagnetic frequency conversion induction underground heating device for in-situ conversion of oil shale hydrocarbon generation according to claim 9, characterized in that: A water-containing cap (23) is fixedly connected to the lower side of the iron core (5); a gap exists between the water-containing cap (23) and the bottom of the iron core (5).

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