Coupling system based on deep dry hot rock stratum hydrogen storage and geothermal energy development and working method thereof

Abstract

The invention relates to the technical field of new energy development and energy storage, and discloses a coupling system based on deep ground dry hot rock stratum hydrogen storage and geothermal energy development and a working method thereof.The coupling system comprises a ground surface subsystem, a shaft subsystem and a dry hot rock reservoir; the earth surface subsystem comprises a hydrogen production unit, a hydrogen compression and injection module, a power generation combined heat and power supply unit, a gas separation and purification module and a central control system; the gas separation and purification module is connected with a power grid; the shaft subsystem comprises underground extraction equipment, a shaft conveying system and a ground wellhead device; the shaft conveying system comprises an injection well and a production well, the hot dry rock reservoir comprises a plurality of artificial fracture networks which are communicated with one another, and monitoring modules are installed in the artificial fracture networks. Large-scale hydrogen storage and hot dry rock development are combined, hydrogen storage and efficient geothermal extraction and conversion are synchronously achieved by means of the space, the high-temperature environment and the sealing performance of a hot dry rock reservoir, and the development problem of a hydrogen storage and enhanced geothermal system is solved.

Description

Technical Field

[0001] This invention relates to the field of new energy development and energy storage technology, and in particular to a coupled system and its working method based on hydrogen storage and geothermal energy development in deep dry hot rock formations. Background Technology

[0002] Current mainstream hydrogen storage methods all suffer from insurmountable drawbacks. High-pressure gaseous hydrogen storage is widely used, technologically mature, and allows for rapid charging and discharging, but it requires compressing hydrogen to 35-70 MPa, resulting in high energy consumption, large equipment investment, and the risk of leakage and explosion in high-pressure containers. It also suffers from low hydrogen storage density, limiting its application to short-distance, small-scale scenarios. Liquid hydrogen storage offers high density, suitable for long-distance transportation and large-scale storage, but it requires cooling hydrogen to an extremely low temperature of -252.78°C, relying on complex refrigeration systems, leading to high energy consumption, significant cooling losses, and easy evaporation. This places extremely high demands on storage container materials, limiting large-scale applications. While material-based hydrogen storage is considered a promising technology due to its safety, mild operation, and high density, metal hydrides have short cycle lives and high costs; carbon materials have low hydrogen storage density at room temperature and pressure, requiring low temperature and high pressure to achieve the desired results; and metal-organic framework materials have high synthesis costs, and their stability and hydrogen storage performance in practical applications need improvement. Current technologies cannot meet the comprehensive requirements of the hydrogen energy industry regarding cost, energy consumption, safety, and scale.

[0003] Hot dry rock is a clean energy source located more than 3 km underground, with temperatures exceeding 180°C (some exceeding 300°C). It boasts abundant reserves and is clean and sustainable. However, its low permeability necessitates development through enhanced geothermal systems. This involves drilling injection wells to inject high-pressure water, creating a network of interconnected fractures within the rock strata. Production wells are then drilled to extract the high-temperature working fluid after heat absorption, which is used for surface power generation. The cooled working fluid is then treated and recycled. However, traditional systems face challenges such as declining heat extraction efficiency, high water consumption, potential for inducing microseismic events, and poor economic returns.

[0004] To this end, a coupled system and its working method based on hydrogen storage and geothermal energy development in deep dry hot rock formations are proposed. Summary of the Invention

[0005] The purpose of this invention is to provide a coupling system and its working method based on hydrogen storage and geothermal energy development in deep dry hot rock formations, aiming to solve or improve at least one of the above-mentioned technical problems.

[0006] To achieve the above objectives, the present invention provides the following solution: The present invention provides a coupling system based on deep-earth dry hot rock strata hydrogen storage and geothermal energy development, comprising: The surface subsystem includes a hydrogen production unit, a hydrogen compression and injection module, a power generation and combined heat and power unit, a gas separation and purification module, and a central control system; the gas separation and purification module is connected to the power grid. The wellbore subsystem includes downhole production equipment, a wellbore delivery system, and a surface wellhead device; the wellbore delivery system includes an injection well and a production well, the production well being connected to the power generation and cogeneration unit and the gas separation and purification module; the surface wellhead device is installed at the wellhead of the production well, and the gas separation and purification module is connected to a hydrogen storage tank; A hot dry rock reservoir, comprising several interconnected artificial fracture networks, wherein a monitoring module is installed within the artificial fracture network, the monitoring module being used to monitor the temperature, pressure, gas concentration within the artificial fracture network and to generate a three-dimensional image of the artificial fracture network; The hydrogen production unit is connected to the injection well via the hydrogen compression and injection module; the injection well and the production well are respectively connected to the artificial fracture network via the downhole production equipment; the hydrogen production unit, the hydrogen compression and injection module, the power generation and cogeneration unit, the gas separation and purification module, and the monitoring module are all connected to the central control system.

[0007] According to the present invention, a coupling system based on hydrogen storage and geothermal energy development in deep dry hot rock formations is provided, wherein the downhole production equipment includes a production screen, a downhole control valve, and a sand packer; The bottom of both the injection well and the production well is equipped with a production screen, which is used to remove particulate matter within the artificial fracture network. Both the injection well and the production well are equipped with downhole control valves, which are located above the production screen. Sand packers are installed between the injection well and the production screen, and between the production well and the production screen. Both the injection well and the production well are equipped with detection equipment, and the detection equipment and the downhole control valve are connected to the central control system. The detection equipment is used to monitor the temperature, pressure and gas flow rate in the injection well and the production well.

[0008] According to the present invention, a coupling system based on deep dry hot rock formation hydrogen storage and geothermal energy development is provided, wherein the wellbore delivery system further includes an insulation layer, and the injection well and the production well are both covered with the insulation layer; both the injection well and the production well are made of high temperature and high pressure resistant steel pipes.

[0009] According to the present invention, a coupled system for hydrogen storage and geothermal energy development based on deep hot dry rock formations is provided, wherein the surface wellhead device includes a gas production tree and a filter separator; the gas production tree is connected to the power generation and cogeneration unit and the gas separation and purification module through pipelines. The gas production tree is installed at the wellhead of the production well to control the production pressure and flow rate of the production well; the filter separator is installed below the gas production tree to remove particulate matter from the produced gas.

[0010] According to the present invention, a coupled system based on hydrogen storage and geothermal energy development in deep dry hot rock formations is provided, wherein the power generation and cogeneration unit includes an evaporator, a turbine, a condenser and a high-pressure pump connected in sequence; the turbine is connected to a generator, and the generator is connected to the power grid. The hydrogen extracted by the gas-collecting tree exchanges heat with the liquid working fluid through the evaporator. The liquid working fluid absorbs heat and evaporates into high-pressure superheated steam. The high-pressure superheated steam drives the turbine impeller to rotate, thereby driving the generator to generate electricity. The low-pressure steam discharged from the turbine enters the condenser and exchanges heat with the cooling water inside the condenser. The low-pressure steam condenses into a liquid working fluid, and the cooling water is heated to provide industrial heating. The liquid working fluid is connected to the evaporator through the high-pressure pump.

[0011] According to the present invention, a coupling system based on hydrogen storage and geothermal energy development in deep dry hot rock formations is provided, wherein the monitoring module includes a pressure sensor array, a temperature sensor array, a gas concentration sensor array, and a seismic wave imaging device; The pressure sensor array, temperature sensor array, and gas concentration sensor array are all installed within the artificial fracture network, and the seismic wave imaging device is used to generate a three-dimensional image of the artificial fracture network. The pressure sensor array, temperature sensor array, gas concentration sensor array, and seismic wave imaging device are all electrically connected to the central control system.

[0012] According to the present invention, a coupled system based on deep-earth dry hot rock strata hydrogen storage and geothermal energy development is provided, wherein the hydrogen production unit is any one or more of the following: water electrolysis hydrogen production device, natural gas reforming hydrogen production device, coal hydrogen production device, and biomass gasification hydrogen production device; the hydrogen production unit is connected to a power station, wherein the power station is a photovoltaic power station or a wind power station. The hydrogen compression and injection module includes a multi-stage compressor and a pressure control system. The multi-stage compressor is electrically connected to the central control system through the pressure control system, and the hydrogen production unit is connected to the injection well through the multi-stage compressor.

[0013] This invention also provides a working method for a coupled system based on hydrogen storage and geothermal energy development in deep dry hot rock formations, comprising the following steps: Step 1: Drill at least one injection well and one production well in the dry hot rock target area selected by geological exploration; Step 2: Hydraulic fracturing is performed on the target section of the hot dry rock reservoir through injection wells to form several artificial fracture networks in the high-temperature rock mass under high pressure fluid. The bottoms of the injection wells and production wells are connected to the artificial fracture networks through downhole production equipment. Several artificial fracture networks form a connected artificial hot dry rock reservoir. Catalysts are placed within the artificial fracture networks. Step 3: Monitor the temperature, pressure, and gas concentration within the artificial fracture network using the monitoring module, and generate a three-dimensional image of the artificial fracture network; Step 4: Select the system operating mode, which includes hydrogen storage and charging mode, power generation and heating mode, and peak shaving and coordinated coupling mode. During periods of low grid load or excess renewable energy generation, a hydrogen storage and charging mode is adopted. The specific operation of the hydrogen storage and charging mode is as follows: start the hydrogen production unit to produce hydrogen, compress it and inject it into the artificial dry hot rock reservoir through the injection well. The hydrogen is stored and heated in the artificial fracture network. During peak electricity consumption periods, a power generation and heating mode is adopted. The specific operation of the power generation and heating mode is as follows: the injection well is closed, the production well is opened, and the high-temperature and high-pressure hydrogen is extracted and first used to generate electricity and recover waste heat through the power generation and cogeneration unit. Then, after being purified by the gas separation and purification module, the high-purity hydrogen is transported to the hydrogen storage tank. When the peak shaving and coordinated coupling mode is adopted, the specific operation of the peak shaving and coordinated coupling mode is as follows: the central control system dynamically switches or mixes the hydrogen storage and charging mode and the power generation and heating mode to realize the grid peak shaving and valley filling and efficient energy allocation.

[0014] According to the present invention, a working method for a coupled system based on deep dry hot rock formation hydrogen storage and geothermal energy development is provided, wherein the lengths of the injection well and the production well are both greater than 3000m, and the distance between the injection well and the production well is 500m to 1000m.

[0015] According to the present invention, in step three, when the monitoring module detects an abnormal decrease in pressure or gas concentration in the artificial fracture network, the central control system triggers an alarm and adjusts the operating parameters of the hydrogen production unit, the hydrogen compression and injection module, the power generation and cogeneration unit, and the gas separation and purification module.

[0016] The present invention discloses the following technical effects: This invention utilizes injection wells to hydraulically fracturing target sections of hot dry rock reservoirs, creating a network of artificial fractures within the high-pressure, high-temperature rock mass. By leveraging the vast space and excellent sealing properties of the hot dry rock reservoir, it transforms deep-earth hot dry rock reservoirs into a comprehensive energy hub simultaneously possessing three major functions: hydrogen geological storage, geothermal power generation and heating, and system peak shaving. This achieves efficient, safe, and synergistic energy utilization. By organically integrating hydrogen storage, geothermal extraction, and grid peak shaving into a single system, it enables large-scale, long-term, and low-cost hydrogen storage, effectively improving the utilization efficiency of underground space and the economic viability of the project. This invention uses hydrogen as the working fluid, which has low viscosity and good fluidity. Compared with water, it can penetrate artificial fracture networks more effectively, extracting heat from deeper and wider areas, thus improving thermal extraction efficiency and power plant storage capacity. At the same time, the injection of hydrogen can maintain and enhance the pressure of hot dry rock reservoirs, alleviating the efficiency decline problem caused by pressure drop in traditional enhanced geothermal systems. Under the high temperature conditions of hot dry rock reservoirs, hydrogen may undergo weak chemical reactions with rocks (such as reactions with Fe³⁺ in the rocks), which can fix some H₂, enhancing storage safety and potentially generating water to replenish some formation fluids. This invention is a clean energy system based on renewable energy and geothermal energy, possessing bidirectional peak-shaving capabilities. It uses electricity to produce and store hydrogen as a load on the power grid, and also generates electricity to supply heat, offering high flexibility. This invention combines large-scale hydrogen storage demand with the development of hot dry rock geothermal energy, utilizing the vast space, high-temperature environment, and enclosed nature of hot dry rock reservoirs to simultaneously achieve hydrogen storage and efficient geothermal extraction and conversion. It has enormous technological potential, economic value, and environmental benefits. This novel "three-in-one" energy solution opens up new paths for the development of the new energy industry, promotes the optimization and upgrading of the energy structure, and has broad application prospects and important strategic significance. Attached Figure Description

[0017] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 This is a schematic diagram of the combined heat and power (CHP) unit in this invention.

[0019] The components include: 1. Power plant; 2. Hydrogen production unit; 3. Hydrogen compression and injection module; 4. Hot dry rock reservoir; 5. Insulation layer; 6. Injection well; 7. Detection equipment; 8. Downhole control valve; 9. Sand packer; 10. Production screen; 11. Artificial fracture network; 12. Catalyst; 13. Pressure sensor array; 14. Production well; 15. Tree gas system; 16. Filter separator; 17. Power generation and combined heat and power unit; 171. Evaporator; 172. Turbine; 173. Generator; 174. Condenser; 175. High-pressure pump; 18. Gas separation and purification module; 19. Hydrogen storage tank; 20. Power grid; 21. Central control system; 22. Industrial heat. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0022] Reference Figures 1-2 This invention provides a coupled system for hydrogen storage and geothermal energy development based on deep dry hot rock formations, comprising: The surface subsystem includes a hydrogen production unit 2, a hydrogen compression and injection module 3, a power generation and cogeneration unit 17, a gas separation and purification module 18, and a central control system 21; the gas separation and purification module 18 is connected to the power grid 20. The wellbore subsystem includes downhole production equipment, a wellbore delivery system, and a surface wellhead device. The wellbore delivery system includes an injection well 6 and a production well 14. The production well 14 is connected to a power generation and cogeneration unit 17 and a gas separation and purification module 18. The surface wellhead device is installed at the wellhead of the production well 14, and the gas separation and purification module 18 is connected to a hydrogen storage tank 19. The hot dry rock reservoir 4 includes several interconnected artificial fracture networks 11. A monitoring module is installed within each artificial fracture network 11 to monitor the temperature, pressure, gas concentration, and generate a three-dimensional image of the artificial fracture network 11. The temperature of the hot dry rock reservoir 4 is greater than 180°C. Among them, the hydrogen production unit 2 is connected to the injection well 6 through the hydrogen compression and injection module 3; the injection well 6 and the production well 14 are respectively connected to the artificial fracture network 11 through the downhole production equipment; the hydrogen production unit 2, the hydrogen compression and injection module 3, the power generation and cogeneration unit 17, the gas separation and purification module 18 and the monitoring module are all connected to the central control system 21. With this setup, the present invention uses injection well 6 to hydraulically fracturing the target section of the hot dry rock reservoir 4, forming a network of artificial fractures 11 in the high-temperature rock mass under high pressure and fluid conditions. Utilizing the vast space and excellent sealing properties of the hot dry rock reservoir 4, the deep-earth hot dry rock reservoir 4 is transformed into a comprehensive energy hub with three major functions: hydrogen geological storage, geothermal power generation and heating, and system peak shaving. This achieves efficient, safe, and synergistic energy utilization. By organically integrating hydrogen storage, geothermal extraction, and grid peak shaving into one system, large-scale, long-term, and low-cost hydrogen storage can be achieved, effectively improving the utilization efficiency of underground space and the economics of the project. This invention uses hydrogen as the working fluid, which has low viscosity and good fluidity. Compared with water, it can penetrate the artificial fracture network 11 more effectively, extracting heat from deeper and wider areas, thus improving thermal extraction efficiency and power plant storage capacity. At the same time, the injection of hydrogen can maintain and enhance the pressure of the hot dry rock reservoir 4, alleviating the efficiency decline problem caused by pressure drop in traditional enhanced geothermal systems. Under the high temperature conditions of the hot dry rock reservoir 4, the weak chemical reaction that hydrogen may have with the rock (such as the reaction with Fe³⁺ in the rock) can fix some H2, which not only enhances storage safety but may also generate water to replenish some formation fluids. This invention is a clean energy system based on renewable energy and geothermal energy, possessing bidirectional peak-shaving capabilities. It uses electricity to produce and store hydrogen as a load on the power grid, and also generates electricity to supply heat, offering high flexibility. This invention combines large-scale hydrogen storage demand with the development of hot dry rock geothermal energy, utilizing the vast space, high-temperature environment, and enclosed nature of hot dry rock reservoirs to simultaneously achieve hydrogen storage and efficient geothermal extraction and conversion. It has enormous technological potential, economic value, and environmental benefits. This novel "three-in-one" energy solution opens up new paths for the development of the new energy industry, promotes the optimization and upgrading of the energy structure, and has broad application prospects and important strategic significance.

[0023] The scheme has been further optimized, and the downhole production equipment includes a production screen pipe 10, a downhole control valve 8, and a sand packer 9; Both the bottom of injection well 6 and the bottom of production well 14 are equipped with production screens 10, which are used to remove particles from the artificial fracture network 11. Downhole control valves 8 are installed in both injection well 6 and production well 14, located above the production screens 10. Sand packers 9 are installed between injection well 6 and the production screens 10, and between production well 14 and the production screens 10. Sand packers 9 are used to isolate the reservoir from the wellbore annulus, preventing sand particles from entering the annulus and damaging the casing, while also fixing the screen position. The material must be the same as the screen, and the sealing performance must meet the high pressure differential requirements.

[0024] Both injection well 6 and production well 14 are equipped with detection equipment 7. The detection equipment 7 and downhole control valve 8 are connected to the central control system 21. The detection equipment 7 is used to monitor the temperature, pressure and gas flow rate in injection well 6 and production well 14. The production screen 10 contacts the artificial fracture network 11. Its porous structure can intercept particles (such as rock chips and sand) generated by rock mass breakage, preventing particles from entering the wellbore with hydrogen or hot fluid, preventing pipeline blockage or equipment wear, and ensuring smooth fluid transport. The sand packer 9 is installed between the wellbore and the production screen 10. It isolates the annular space of the wellbore from the screen area through expansion sealing, preventing formation sand from entering the wellbore and preventing the injected or produced hydrogen / hot fluid from leaking from the annular space, thus enhancing the wellbore sealing.

[0025] The material of the production screen tube 10 should meet the requirements of resistance to hydrogen embrittlement, high temperature resistance (300-500℃ in dry hot rock reservoirs), and corrosion resistance (salt staining and CO2 corrosion in saline water layers). The screen hole size should match the reservoir porosity.

[0026] Downhole control valve 8 is located above the production screen 10 and is regulated by the central control system 21. Its opening can be dynamically adjusted according to the system's operating mode: In hydrogen storage and charging mode, downhole control valve 8 of injection well 6 is fully open to ensure efficient hydrogen injection into the artificial fracture network 11, while downhole control valve 8 of production well 14 is closed to prevent hydrogen leakage; in power generation and heating mode, downhole control valve 8 of production well 14 opens as needed to control the production flow of high-temperature, high-pressure hydrogen, while downhole control valve 8 of injection well 6 is closed to prevent unstored hydrogen from mixing into the produced gas flow. Downhole control valve 8 is hydraulically or electrically controlled and its opening can be remotely adjusted via surface signals to adapt to changes in reservoir pressure.

[0027] The detection device 7 monitors the temperature, pressure, and gas flow data in the injection well 6 and the production well 14 in real time and transmits the signals to the central control system 21. When the pressure in the injection well is detected to be lower than the preset value, the system can increase the compressor pressure through the hydrogen compression injection module 3 to ensure smooth hydrogen injection. If the gas flow in the production well 14 drops abnormally, the pressure data can be combined to determine whether there is screen tube blockage or unobstructed fracture channel, and maintenance instructions can be triggered in time to ensure stable system operation.

[0028] Further optimization of the scheme includes an insulation layer 5 in the wellbore delivery system, which is also fitted around both the injection well 6 and the production well 14. Both the injection well 6 and the production well 14 utilize high-temperature and high-pressure resistant steel pipes to withstand underground temperatures of 300-500℃ and pressures of 10-50MPa. For saline or CO2 mixed reservoirs, additional anti-corrosion coatings (such as epoxy powder or polyurea) are required to prevent salt or CO2 corrosion.

[0029] For high-temperature reservoirs such as hot dry rock, the wellbore needs to be equipped with an insulation layer 5 (such as foam glass or aluminum silicate fiber) to reduce heat loss during hydrogen extraction and ensure that the subsequent heat exchange system can effectively recover residual heat.

[0030] The scheme is further optimized. The surface wellhead device includes a gas production tree 15 and a filter separator 16. The gas production tree 15 is connected to the power generation and cogeneration unit 17 and the gas separation and purification module 18 through pipelines. The gas production tree 15 is installed at the wellhead of the production well 14 to control the production pressure and flow rate of the production well 14; the filter separator 16 is installed below the gas production tree 15 to remove particulate matter from the produced gas. The wellhead (Tree of Gas) is used to control the produced pressure and flow rate, serving as a "valve hub" between the surface and the wellbore. It includes components such as a main valve (to cut off fluid in the well), a choke valve (to regulate flow rate), and a pressure sensor (to monitor wellhead pressure). The material should be resistant to hydrogen corrosion (such as Monel alloy or duplex steel), and the design pressure should be 1.5-2 times higher than the reservoir pressure (e.g., if the reservoir pressure is 30 MPa, the design pressure of the wellhead should be ≥45 MPa).

[0031] The filter separator 16 is used to remove small particulate matter (≤10μm) from the extracted gas to prevent it from entering subsequent gas separation and purification modules (such as pressure swing adsorption devices) and damaging the adsorbent or valves.

[0032] The scheme is further optimized. The combined heat and power generation unit 17 includes an evaporator 171, a turbine 172, a condenser 174 and a high-pressure pump 175 connected in sequence; the turbine 172 is connected to a generator 173, and the generator 173 is connected to the power grid 20. The hydrogen gas extracted by the gas-collecting tree 15 exchanges heat with the liquid working medium through the evaporator 171. The liquid working medium absorbs heat and evaporates into high-pressure superheated steam. The high-pressure superheated steam drives the impeller of the turbine 172 to rotate, driving the generator 173 to generate electricity. The low-pressure steam discharged from the turbine 172 enters the condenser 174 and exchanges heat with the cooling water in the condenser 174. The low-pressure steam condenses into a liquid working fluid, and the cooling water is heated to provide heating for industrial heat 22. The liquid working fluid is connected to the evaporator 171 through the high-pressure pump 175.

[0033] The scheme has been further optimized, and the monitoring module includes a pressure sensor array 13, a temperature sensor array, a gas concentration sensor array, and a seismic wave imaging device; The pressure sensor array 13, temperature sensor array, and gas concentration sensor array are all installed within the artificial fracture network 11. The seismic wave imaging device is used to generate a three-dimensional image of the artificial fracture network 11. The pressure sensor array 13, temperature sensor array, gas concentration sensor array, and seismic wave imaging equipment are all electrically connected to the central control system 21; The pressure sensor array 13 consists of multiple silicon pressure-sensitive cores. Each core converts pressure changes in the crack into electrical signals through the piezoelectric effect. It integrates a digital compensation algorithm for temperature and pressure composite errors to eliminate the influence of temperature fluctuations on pressure measurement and ensure accuracy. At the same time, it adopts a redundant structure so that monitoring continuity can be maintained even if a single sensor fails.

[0034] Gas concentration sensor arrays are used for tracer gas monitoring. Their function is to inject chemically inert, easily detectable tracer gases into fractures or surrounding formations, and then monitor the concentration distribution of these tracer gases in real time. If the fracture remains stable, the tracer gas will be confined to the target area, and its concentration will remain stable. If a leak occurs in the fracture, the tracer gas will diffuse through the fracture channels to the monitoring point, causing an abnormal increase or decrease in concentration.

[0035] Seismic wave imaging equipment is used for seismic wave imaging. Its function is to capture the reflection and refraction of seismic waves as they pass through fractures due to the fracture interface. Through active or passive seismic imaging, combined with inversion algorithms, three-dimensional images of the fractures can be generated. To ensure the physical and chemical stability of hydrogen, catalysts are used to promote a weak chemical reaction between hydrogen and reservoir rocks, thereby enhancing storage stability.

[0036] Further optimizing the scheme, hydrogen production unit 2 can be any one or more of the following: water electrolysis hydrogen production unit, natural gas reforming hydrogen production unit, coal hydrogen production unit, and biomass gasification hydrogen production unit; hydrogen production unit 2 is connected to power station 1, which can be a photovoltaic power station or a wind power station; hydrogen is produced using fossil fuels such as natural gas and coal as raw materials through steam reforming or partial oxidation processes; hydrogen is produced using biomass such as crop straw, forestry waste, and organic waste as raw materials through gasification reaction, followed by water-gas conversion and purification. The hydrogen compression and injection module 3 includes a multi-stage compressor and a pressure control system. The multi-stage compressor is electrically connected to the central control system 21 through the pressure control system. The hydrogen production unit 2 is connected to the injection well 6 through the multi-stage compressor. The multi-stage compressor decomposes the high-pressure compression process of hydrogen into multiple continuous low-compression ratio stages. Through the cycle of "compression-cooling-recompression", the hydrogen pressure is gradually increased, thereby solving the problems of increased energy consumption, excessive temperature, and increased leakage risk caused by excessive single-stage compression ratio, and meeting the needs of deep well transportation and underground storage.

[0037] Further optimization of the solution involves integrating membrane separation technology or pressure swing adsorption (PSA) technology into the gas separation and purification module 18. PSA utilizes the characteristic that the adsorption capacity of an adsorbent changes with pressure to achieve separation, making it suitable for scenarios where the hydrogen concentration in the extracted gas from hot dry rock is low or where high-purity hydrogen is required. Its advantages are high purity and strong adaptability. The hydrogen in the extracted gas is purified to ensure that the purity of the exported hydrogen meets the standards. The process includes: adsorption (carbon dioxide, nitrogen, methane, etc. are adsorbed onto the surface of the adsorbent), pressure equalization (high-pressure hydrogen is introduced into the next column to reduce the pressure inside the column), desorption (adsorbed impurities are desorbed and enter the desorption tank), rinsing (pure hydrogen from the product side is used to rinse away residual impurity gases), and pressurization (the hydrogen recovered in the pressure equalization step and hydrogen from the product side are used to pressurize the column).

[0038] To further optimize the scheme, the central control system 21 constructs a closed-loop system of "underground sensing - ground centralized control - intelligent scheduling": Underground sensing: temperature distribution, pressure changes, and hydrogen concentration of the reservoir; Ground centralized control: setting up a centralized control center to integrate underground data with the status of ground facilities, and achieving unified scheduling and optimization through cable connection; Intelligent scheduling: integrating the remote control interface of ground equipment to achieve remote operation.

[0039] Further optimization of the scheme allows the 20% hydrogen from the power grid to be used in ammonia synthesis and fertilizer production, petroleum refining and hydrogenation, metal smelting and electronics industry, and fuel cell power generation. In fuel cell power generation, hydrogen is electrocatalytically oxidized into protons at the anode, releasing electrons. The electrons form an electric current through an external circuit. The protons pass through the electrolyte to the cathode, where they combine with oxygen to form water. If combined with cogeneration, efficiency can be further improved. When pure hydrogen is used as fuel, there are no pollutant emissions, making it suitable for power grid peak shaving.

[0040] This invention also provides a working method for a coupled system based on hydrogen storage and geothermal energy development in deep dry hot rock formations, comprising the following steps: Step 1: Drill at least one injection well 6 and one production well 14 in the dry hot rock target area selected by geological exploration; Step 2: Hydraulic fracturing is performed on the target section of the hot dry rock reservoir 4 through injection well 6 to form several artificial fracture networks 11 in the high-pressure fluid and high-temperature rock mass. The bottoms of injection well 6 and production well 14 are connected to the artificial fracture network 11 through downhole production equipment. Several artificial fracture networks 11 form a connected artificial hot dry rock reservoir 4. Catalyst 12 is placed in the artificial fracture network 11. Step 3: Monitor the temperature, pressure, and gas concentration within the artificial fracture network 11 using the monitoring module, and generate a three-dimensional image of the artificial fracture network 11. Step 4: Select the system operating mode. The system operating modes include hydrogen storage and charging mode, power generation and heating mode, and peak shaving and coordinated coupling mode. During periods of low load on the power grid or excess renewable energy generation, a hydrogen storage and charging mode is adopted. The specific operation of the hydrogen storage and charging mode is as follows: start the hydrogen production unit 2 to produce hydrogen, which is then compressed and injected into the artificial dry hot rock reservoir 4 through the injection well 6. The hydrogen is stored and heated in the artificial fracture network 11. During peak electricity consumption periods, a power generation and heating mode is adopted. The specific operation of the power generation and heating mode is as follows: the injection well 6 is closed, the production well 14 is opened, and the high-temperature and high-pressure hydrogen is extracted and first used to generate electricity and recover waste heat through the power generation and cogeneration unit 17. Then, after being purified by the gas separation and purification module 18, the high-purity hydrogen is transported to the hydrogen storage tank 19. When adopting the peak-shaving and coordinated coupling mode, the specific operation of the peak-shaving and coordinated coupling mode is as follows: the central control system 21 dynamically switches or mixes between hydrogen storage and charging modes and power generation and heating modes to achieve peak shaving and valley filling and efficient energy allocation of the power grid 20. The central control system 21 monitors the temperature, pressure and flow rate downhole in real time through the detection equipment 7. Based on real-time data and prediction models, the injection or production rate and start-up and shutdown timing are dynamically adjusted to optimize system efficiency and peak-shaving benefits. Multiple safety interlocking mechanisms are set up to prevent overpressure, leakage or reservoir collapse and ensure long-term stable operation.

[0041] The scheme was further optimized so that the lengths of both injection well 6 and production well 14 are greater than 3000m, and the distance between injection well 6 and production well 14 is 500m to 1000m.

[0042] Further optimize the scheme. In step three, when the monitoring module detects an abnormal drop in pressure or a drop in gas concentration in the artificial fracture network 11, the central control system 21 triggers an alarm and adjusts the operating parameters of the hydrogen production unit 2, the hydrogen compression and injection module 3, the power generation and cogeneration unit 17, and the gas separation and purification module 18.

[0043] In the description of this invention, it should be understood that the terms "longitudinal", "lateral", "up", "down", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this invention, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this invention.

[0044] Obviously, the above embodiments of the present invention are merely examples for clearly illustrating the present invention, and are not intended to limit the implementation of the present invention. For those skilled in the art, other variations or modifications can be made based on the above description. It is neither necessary nor possible to exhaustively describe all embodiments here. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A coupling system based on deep geothermal rock layer hydrogen storage and geothermal energy development, characterized in that, The system comprises: a ground surface subsystem comprising a hydrogen production unit (2), a hydrogen compression and injection module (3), a power generation and heat cogeneration unit (17), a gas separation and purification module (18), and a central control system (21); the gas separation and purification module (18) is connected with a power grid (20); a wellbore subsystem comprising downhole production equipment, a wellbore transportation system, and a ground surface wellhead device; the wellbore transportation system comprises an injection well (6) and a production well (14), the production well (14) is connected with the power generation and heat cogeneration unit (17) and the gas separation and purification module (18); the ground surface wellhead device is installed at the wellhead of the production well (14), and the gas separation and purification module (18) is connected with a hydrogen storage tank (19); a hot dry rock reservoir (4) comprising a plurality of interconnected artificial fracture networks (11), a monitoring module is installed in the artificial fracture networks (11), and the monitoring module is used to monitor the temperature, pressure, and gas concentration in the artificial fracture networks (11) and generate a three-dimensional image of the artificial fracture networks (11). The hydrogen production unit (2) is connected with the injection well (6) through the hydrogen compression and injection module (3); the injection well (6) and the production well (14) are respectively connected with the artificial fracture networks (11) through the downhole production equipment, and the hydrogen production unit (2), the hydrogen compression and injection module (3), the power generation and heat cogeneration unit (17), the gas separation and purification module (18), and the monitoring module are all connected with the central control system (21).

2. The system according to claim 1, wherein: The downhole production equipment comprises a production screen pipe (10), a downhole control valve (8), and a sand control packer (9); the bottom of the injection well (6) and the bottom of the production well (14) are both provided with the production screen pipe (10), which is used for particulate matter in the artificial fracture networks (11); the injection well (6) and the production well (14) are both provided with the downhole control valve (8), which is located above the production screen pipe (10); the injection well (6) and the production well (14) are both provided with the sand control packer (9) between the injection well (6) and the production screen pipe (10) and between the production well (14) and the production screen pipe (10); the injection well (6) and the production well (14) are both provided with a detection device (7), and the detection device (7) and the downhole control valve (8) are both connected with the central control system (21); the detection device (7) is used to monitor the temperature, pressure, and gas flow rate in the injection well (6) and the production well (14).

3. The system according to claim 1, wherein: The wellbore transportation system further comprises an insulation layer (5), and the injection well (6) and the production well (14) are both provided with the insulation layer (5); the injection well (6) and the production well (14) both adopt high-temperature and high-pressure steel pipes.

4. The system according to claim 1, wherein: The ground wellhead device comprises a gas production tree (15) and a filter separator (16); the gas production tree (15) is connected with the power generation heat and power cogeneration unit (17) and the gas separation and purification module (18) through a pipeline; The gas production tree (15) is installed at the wellhead of the production well (14) and is used for controlling the production pressure and flow of the production well (14); the filter separator (16) is installed below the gas production tree (15) and is used for removing particulate matters in the produced gas.

5. The system according to claim 4, wherein: The power generation heat and power cogeneration unit (17) comprises an evaporator (171), a turbine (172), a condenser (174) and a high-pressure pump (175) connected in sequence; the turbine (172) is connected with a generator (173), and the generator (173) is connected with the power grid (20); The hydrogen produced by the gas production tree (15) exchanges heat with a liquid working medium through the evaporator (171), the liquid working medium absorbs heat to evaporate into high-pressure superheated steam, the high-pressure superheated steam drives the impeller of the turbine (172) to rotate, and drives the generator (173) to generate electricity; The low-pressure steam discharged from the turbine (172) enters the condenser (174) and exchanges heat with cooling water in the condenser (174), the low-pressure steam condenses into liquid working medium, the cooling water is heated and used for industrial heat (22) and heating; the liquid working medium communicates with the evaporator (171) through the high-pressure pump (175).

6. The system according to claim 1, wherein: The monitoring module comprises a pressure sensor array (13), a temperature sensor array, a gas concentration sensor array and a seismic wave imaging device; The pressure sensor array (13), the temperature sensor array, the gas concentration sensor array are all installed in the artificial fracture network (11), and the seismic wave imaging device is used for generating a three-dimensional image of the artificial fracture network (11); The pressure sensor array (13), the temperature sensor array, the gas concentration sensor array and the seismic wave imaging device are all electrically connected with the central control system (21).

7. The system according to claim 1, wherein: The hydrogen production unit (2) is any one or several of an electrolytic water hydrogen production device, a natural gas reforming hydrogen production device, a coal hydrogen production device and a biomass gasification hydrogen production device; the hydrogen production unit (2) is connected with a power station (1), and the power station (1) is a photovoltaic power station or a wind power station; The hydrogen gas compression and injection module (3) comprises a multi-stage compressor and a pressure regulation system, the multi-stage compressor is electrically connected with the central control system (21) through the pressure regulation system, and the hydrogen production unit (2) is connected with the injection well (6) through the multi-stage compressor.

8. A method for operating a system for coupling the development of geothermal energy with the storage of hydrogen in deep dry hot rock formations according to any one of claims 1 to 7, characterized in that The method comprises the following steps: Step one, drilling at least one injection well (6) and one production well (14) in a dry hot rock target area selected in geological exploration; Step two, hydraulic fracturing is performed on the target section of the hot dry rock reservoir (4) through the injection well (6) to form a plurality of artificial fracture networks (11) in the high-temperature rock mass of the high-pressure fluid, the bottom of the injection well (6) and the production well (14) is connected with the artificial fracture network (11) through the downhole production equipment, and the plurality of artificial fracture networks (11) form a connected artificial hot dry rock reservoir (4); a catalyst (12) is arranged in the artificial fracture network (11); Step three, the temperature, pressure, gas concentration in the artificial fracture network (11) and the three-dimensional image of the artificial fracture network (11) are monitored through the monitoring module; Step four, selecting a system operation mode, the system operation mode includes a hydrogen storage and charging mode, a power generation and heat supply mode, and a peak shaving and collaborative coupling mode; In the low load valley period of the power grid (20) or the excess renewable energy generation period, the hydrogen storage and charging mode is adopted, and the specific operation of the hydrogen storage and charging mode is that the hydrogen production unit (2) is started to produce hydrogen, which is compressed and injected into the artificial hot dry rock reservoir (4) through the injection well (6), and the hydrogen is stored and heated in the artificial fracture network (11); In the power consumption peak period, the power generation and heat supply mode is adopted, and the specific operation of the power generation and heat supply mode is that the injection well (6) is closed, and the production well (14) is opened, the high-temperature and high-pressure hydrogen is recovered and the waste heat is recovered through the power generation and heat supply unit (17), and then the high-purity hydrogen is purified through the gas separation and purification module (18) and then transported to the hydrogen storage tank (19); When the peak shaving and collaborative coupling mode is adopted, the specific operation of the peak shaving and collaborative coupling mode is that the central control system (21) dynamically switches or mixedly operates between the hydrogen storage and charging mode and the power generation and heat supply mode, so as to realize the peak shaving and valley filling of the power grid (20) and the efficient energy allocation.

9. The method according to claim 8, wherein: The length of the injection well (6) and the production well (14) is greater than 3000m, and the distance between the injection well (6) and the production well (14) is 500m-1000m.

10. The method of claim 8, wherein the method further comprises: In step three, when the monitoring module detects that the pressure of the artificial fracture network (11) abnormally decreases or the gas concentration decreases, the central control system (21) triggers an alarm and adjusts the operating parameters of the hydrogen production unit (2), the hydrogen compression injection module (3), the power generation and heat supply unit (17), and the gas separation and purification module (18).

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