Integrated energy system and method for coupling water-bearing stratum gas storage and pumped storage

Abstract

The invention discloses a comprehensive energy system and method for coupling water-bearing stratum gas storage and pumped storage. According to the system, an injection-production pipeline, a drainage pipeline and a water injection pipeline are inserted into an injection-production well, a drainage well and a water injection well correspondingly; the elastic air cushion covers the inner side wall of the reservoir box body, and an elastic water storage space is formed in the elastic air cushion; a water outlet and a water inlet of the water pump are respectively connected with a water inlet and a drainage pipeline of the ground reservoir; the communicating pipeline is connected with a water outlet of the ground reservoir and the water injection pipeline. The electromagnetic valve and the hydraulic generator are sequentially connected to the communicating pipeline in series; and one working gas port of the gas pump is connected with a gas path interface of the ground gas storage through the gas purification pressure regulating mechanism, and the other working gas port of the gas pump is connected with the upper end of the injection-production pipeline. The method comprises system arrangement; when wind-solar power generation is surplus or the load of the power grid is off-peak, energy storage and energy charging are carried out through water pumping and gas injection; and power generation operation is carried out through gas production and water injection in a gas consumption peak. Interconversion and storage of electric energy, pressure potential energy and water level potential energy can be achieved.

Description

Technical Field

[0001] This invention belongs to the field of energy engineering technology, specifically relating to an integrated energy system and method that couples aquifer gas storage and pumped storage. Background Technology

[0002] With the increasing proportion of intermittent renewable energy sources such as wind power and photovoltaics, the pressure on power grid peak shaving is growing. At the same time, there is a significant "evening peak" phenomenon in urban natural gas consumption. Currently, these two problems are usually solved with separate solutions: pumped storage hydroelectric power stations are commonly used for power grid peak shaving; underground gas storage facilities (such as depleted gas reservoirs and salt cavern gas storage facilities) are used for gas consumption peak shaving.

[0003] Pumped storage power stations, as an energy storage technology that utilizes the water level difference between upper and lower reservoirs to achieve efficient conversion between electrical and potential energy, have become a key component in building new power systems against the backdrop of the global green energy transition, thanks to their maturity, reliability, and large-scale operation. They are not only one of the most mature and widely used energy storage methods currently available, but also play an irreplaceable role in promoting the efficient consumption of new energy sources and ensuring the safe and stable operation of the power grid. For my country, the "dual carbon" target is not only an inherent requirement for promoting sustainable development, but also an important path to promote economic restructuring and fulfill its responsibilities as a major power. In this process, pumped storage power stations, based on reliable physical principles, are demonstrating new vitality in today's energy revolution, becoming an indispensable "stabilizer" and "regulator" in the new power system.

[0004] Gas storage facilities, as key gas storage infrastructures, primarily undertake the tasks of natural gas storage and extraction, possessing multiple functions including seasonal peak shaving and supply assurance, pipeline operation optimization, strategic energy reserves, and economic efficiency enhancement. They are mainly divided into two categories: surface storage tanks (such as LNG storage tanks) and underground gas storage facilities (UGS). Underground gas storage facilities can be further classified into various types, such as gas reservoir type, oil reservoir type, salt cavern type, aquifer type, and abandoned mine pit type. As a core link in the natural gas "production, supply, storage, and sales" system, gas storage facilities are of great strategic significance for improving the national natural gas industry, ensuring people's livelihood needs, and maintaining energy security. Aquifer-type gas storage facilities are one of the important forms of underground gas storage facilities. Currently, globally, gas storage facilities located around large industrial centers and major cities are mostly aquifer-type. In my country, most oil and gas reservoirs are distributed in terrestrial strata, with a limited overall scale, thus limiting the potential for converting depleted oil and gas reservoirs into gas storage facilities. While most large industrial cities and metropolitan areas may not have depleted oil and gas fields suitable for gas storage, suitable underground aquifer structures can usually be found. In such cases, constructing aquifer-type underground gas storage facilities becomes the preferred technical approach.

[0005] However, both methods have limitations: pumped hydro storage is severely restricted by geographical conditions and has a single function; traditional aquifer gas storage requires injecting large amounts of water to maintain pressure during gas extraction, wasting the potential energy of this water, and then consuming energy to pump the water out during gas injection. Therefore, existing technologies lack an efficient and economical solution that can organically integrate power peak shaving, natural gas peak shaving, and energy recovery and utilization. Therefore, there is an urgent need for a comprehensive energy system and method that couples aquifer gas storage and pumped hydro storage. Summary of the Invention

[0006] To address the problems of existing technologies, this invention provides a comprehensive energy system and method that couples aquifer gas storage with pumped hydro storage. This system is simple in structure and low in investment cost. Through the coupling connection of a surface reservoir, a surface gas storage facility, and an aquifer, it not only utilizes the aquifer as an underground gas storage facility for natural gas but also fully leverages the potential energy conversion and power generation during the natural gas injection and extraction process. By combining the utilization of the aquifer, it achieves a cascaded energy utilization process and organically integrates power peak shaving, natural gas peak shaving, and energy recovery and utilization, resulting in excellent economic and social benefits. This method enables the mutual conversion and storage of electrical energy, pressure potential energy, and water level potential energy. It effectively recovers the potential energy wasted in the injection / extraction process of traditional aquifer gas storage facilities and converts it into electrical energy, improving overall energy efficiency and achieving energy recycling. This recycling process promotes the consumption of new energy sources, provides a large-scale, long-term energy storage outlet for surplus wind and solar power, and smooths grid load fluctuations through power generation, significantly improving economic and social efficiency.

[0007] To achieve the above objectives, the present invention provides an integrated energy system that couples aquifer gas storage and pumped-storage, including a confined aquifer structure, an injection-production well network subsystem, a surface water and gas treatment and storage subsystem, and a power generation and energy management subsystem. The pressurized aquifer structure includes a bottom plate boundary at the bottom, a cap layer at the top of the bottom plate boundary, and an aquifer between the bottom plate boundary and the cap layer. The injection-production well network subsystem includes injection-production wells, drainage wells, water injection wells, injection-production pipelines, drainage pipelines, and water injection pipelines. The injection-production wells, drainage wells, and water injection wells are all vertically arranged and distributed at intervals. The lower ends of the injection-production wells pass through the overlying geological layer and caprock in sequence, ending at the top of the aquifer; the lower ends of the drainage wells and water injection wells pass through the overlying geological layer and caprock in sequence, ending at the bottom of the aquifer; the injection-production pipelines, drainage pipelines, and water injection pipelines are respectively fixedly inserted into the injection-production wells, drainage wells, and water injection wells. The ground water and gas treatment and storage subsystem includes an injection and drainage mechanism and an injection and venting mechanism. The injection and drainage mechanism includes a ground reservoir, a water pump, connecting pipelines, and a solenoid valve. The ground reservoir includes a reservoir body and an elastic air cushion, with the elastic air cushion covering the inner wall of the reservoir body, forming an elastic water storage space inside the elastic air cushion. The outlet of the water pump is connected to the inlet of the ground reservoir, and its inlet is connected to the upper end of the drainage pipeline. The connecting pipeline is connected to the outlet of the ground reservoir and the upper end of the injection pipeline, respectively. The solenoid valve is connected in series in the inlet section of the connecting pipeline. The injection and venting mechanism includes a ground gas storage tank, a gas purification and pressure regulating mechanism, and a gas pump. One working gas port of the gas pump is connected to the gas interface of the ground gas storage tank through the gas purification and pressure regulating mechanism, and the other working gas port of the gas pump is connected to the upper end of the injection and extraction pipeline. The power generation and energy management subsystem includes a power generation unit and an energy management unit; the power generation unit includes a hydro-generator connected in series in the outlet section of the connecting pipeline; the energy management unit is connected to the hydro-generator, solenoid valve, water pump, air pump and gas purification and pressure regulating mechanism respectively.

[0008] As a preferred embodiment, the power generation unit further includes a gas turbine; the gas turbine is connected to a gas purification and pressure regulating mechanism via a gas pipeline.

[0009] As a preferred embodiment, the energy management unit further includes a power module one and a power module two; the power module one is connected to the water pump and the water turbine generator respectively; the power module two is connected to the gas pump and the gas turbine respectively; and the power module one and the power module two are connected by an on / off control circuit.

[0010] As a preferred embodiment, the power generation unit further includes wind and solar power generation equipment; the wind and solar power generation equipment is connected to power module one and power module two, respectively.

[0011] As a preferred embodiment, the energy management unit further includes an inverter and a controller. The inverter is connected to power module one, power module two, and the local power grid, respectively. The controller is connected to the inverter, a hydro generator, a gas turbine, a solenoid valve, a water pump, a gas pump, a gas purification and pressure regulating mechanism, and wind and solar power generation equipment, respectively.

[0012] As a preferred embodiment, the hydro-generator is a reversible pump-turbine.

[0013] In this invention, the lower end of the injection-production well terminates in the top space of the aquifer. This facilitates the injection or extraction of natural gas into the top space of the aquifer using the injection-production well. During injection, the continuously added natural gas provides pressure to the water surface, reducing the suction pressure on the water in the aquifer and improving suction efficiency. The lower ends of both the drainage well and the injection well terminate in the bottom space of the aquifer. This allows for efficient use of the pressure provided by the natural gas during injection to improve the water output efficiency of the drainage well. Furthermore, during extraction, the reinjection pressure from the injection well reduces the suction pressure during natural gas extraction, improving extraction efficiency. The installation of injection-production, drainage, and injection pipelines ensures that the entire gas injection and extraction process, as well as the injection and drainage process, is conducted in a sealed environment, preventing leakage that could reduce operational efficiency. Covering the inner surface of the reservoir tank with an elastic air cushion creates an elastic water storage space within the surface reservoir. During storage, when the water volume exceeds the normal capacity of this elastic space, the air cushion is effectively compressed, thus storing elastic energy. The gas purification and pressure regulating mechanism facilitates the purification and pressure regulation of extracted or injected natural gas, preventing dangerous gases from entering the surface gas storage facility or toxic gases from entering the aquifer. It also allows for the diversion of excess treated natural gas to a gas turbine for power generation during extraction. Solenoid valves on the connecting pipelines allow for convenient control of the pipeline's opening and closing. The branch containing the water pump and drainage pipeline, along with the branch containing the gas pump and injection / production pipeline, forms a coordinated gas injection and water pumping unit. Through their coordinated operation, water pumping can be performed simultaneously with natural gas injection into the aquifer, effectively balancing the pressure within the aquifer. The branch lines connecting the gas pump and water injection pipelines, along with the branch lines containing the gas pump and injection / production pipelines, form a coordinated unit for gas extraction, water injection, and power generation. Through their coordinated operation, while extracting natural gas, the negative pressure of the extraction, the elastic compression of the elastic air cushion, and the gravitational potential energy at a higher elevation are simultaneously applied to the water in the surface reservoir. This causes the water to flow out at high speed and efficiently drive the hydroelectric generator for power generation. Simultaneously, it effectively balances the pressure within the aquifer. The energy management unit facilitates intelligent coordination of the flow of electricity, gas, and water, as well as the energy conversion process.

[0014] This system has a simple structure and low investment cost. It is coupled and connected by a surface reservoir, a surface gas storage facility and an aquifer. It can not only use the aquifer as an underground gas storage facility for natural gas, but also make full use of the natural gas injection and extraction and water flow extraction and reinjection process to realize potential energy conversion and power generation. By making combined use of the aquifer, it realizes the mutual conversion and storage of electrical energy, pressure potential energy and water level potential energy, realizes the two core functions of power energy storage and natural gas energy storage, realizes the energy cascade utilization process, and systematically integrates power peak shaving, natural gas peak shaving and energy recovery and utilization into one, which has excellent economic and social benefits.

[0015] This invention also provides a comprehensive method for coupling aquifer gas storage and pumped hydro storage, employing a comprehensive energy system that couples aquifer gas storage and pumped hydro storage, comprising the following steps: Step 1: Layout of an integrated energy system that couples aquifer gas storage and pumped hydro storage; Step 2: When there is a surplus of wind and solar power or when the local power grid load is low, control the gas pump and water pump to start working simultaneously. Use the water pump to extract water from the aquifer and pump it into the elastic water storage space to ensure that the water injection volume exceeds the normal capacity of the elastic storage space, so as to compress the elastic air cushion to store elastic potential energy. At the same time, use the gas pump to inject natural gas, which has been processed by the gas purification and pressure regulating mechanism, into the aquifer through the injection and production pipeline to maintain the pressure balance in the aquifer. Step 3: During peak gas consumption, the gas pump is started and the solenoid valve is opened. The gas pump extracts natural gas from the aquifer and, after being processed by the gas purification and pressure regulating mechanism, injects it into the ground gas storage tank. At the same time, the negative pressure generated during the gas extraction process, the elastic potential energy stored in the elastic air cushion, and the high-level gravitational potential energy of the ground reservoir are combined to cause water to flow out at high speed. The water is then reinjected into the aquifer through the water turbine generator and the water injection pipeline, synchronously driving the water turbine generator to generate electricity. The generated electrical energy is stored in power module one.

[0016] As a preferred embodiment, in step two, when there is a surplus of wind and solar power, the wind and solar power generation equipment is controlled to generate electricity and the generated electrical energy is stored in power module one or power module two. When the local power grid load is low, the water pump and air pump are connected to the local power grid respectively to facilitate the supply of electricity to the water pump and air pump.

[0017] As a preferred option, in step three, when the natural gas in the ground gas storage facility meets the user's needs, the processed natural gas is transported to the gas turbine for power generation through a gas purification and pressure regulating mechanism, and the generated electricity is stored in power module two.

[0018] To achieve energy conversion, in step three, when the power level in power module one or power module two exceeds the upper threshold, the inverter converts the DC power in power module one or power module two into AC power and outputs it to the local power grid; when the power level in power module one exceeds the upper threshold and the power level in power module two is less than the lower threshold, the on / off control circuit transfers the power from power module one to power module two to charge power module two; when the power level in power module two exceeds the upper threshold and the power level in power module one is less than the lower threshold, the on / off control circuit transfers the power from power module two to power module one to charge power module one.

[0019] This invention provides a comprehensive method that can synergistically absorb new energy sources, simultaneously solve the peak-shaving problems of electricity and gas, and achieve energy cascade utilization. During periods of surplus wind and solar power or low local grid load, the synchronous injection process using water and gas pumps not only injects natural gas into the aquifer, reducing the storage pressure of the surface gas storage facility, but also reduces the water extraction pressure in the aquifer through gas pressure, thus improving water extraction efficiency and effectively maintaining pressure balance within the aquifer. During the water injection process into the elastic water storage space, ensuring that the injected water volume exceeds the normal capacity of the elastic water storage space allows for effective compression of the elastic gas cushion, thereby ensuring the storage of a significant amount of elastic potential energy during this process. During peak gas demand periods, the extraction of natural gas creates negative pressure within the aquifer. Simultaneously, the elastic gas cushion stores elastic potential energy, and the surface reservoir possesses high gravitational potential energy relative to the aquifer. When the solenoid valve is opened, the triple action of negative pressure suction, elastic compression, and gravitational potential energy causes water to flow out at high speed, efficiently driving a hydroelectric generator for high-efficiency power generation. The generated electricity can be directly stored or supplied to other electrical equipment or fed into the local power grid as needed. Furthermore, the simultaneous reinjection during gas extraction effectively replenishes formation pressure, avoiding the instability issues such as sand production and formation deformation that can occur with traditional underground gas storage facilities due to rapid pressure drops, thus improving the stability and safety of the gas storage operation.

[0020] This invention creates a closed-loop system by coordinating a surface reservoir, a surface gas storage facility, an underground aquifer, pipelines, and pumps, with the underground serving as the gas storage facility, the surface as the reservoir, and the wellbore as the power generation channel. It can utilize the aquifer to store gas and store energy, solve the problem of peak gas demand during the gas extraction process, and at the same time, make full use of the water reinjected into the aquifer for efficient power generation. Simultaneously, it can balance the pressure of the aquifer to ensure the efficient operation of gas extraction.

[0021] This method enables the mutual conversion and storage of electrical energy, pressure potential energy, and water level potential energy. It effectively recovers the potential energy wasted in the water injection / extraction process in traditional aquifer gas storage facilities and converts it into electrical energy, thereby improving overall energy efficiency, realizing the recycling of energy, promoting the consumption of new energy sources through the recycling process, providing a large-scale, long-term energy storage outlet for surplus wind and solar power, and smoothing grid load fluctuations through power generation, thus significantly improving economic benefits and social efficiency. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the system portion of the present invention; Figure 2 This is a schematic diagram of the energy system in the energy storage and charging stage of this invention; Figure 3 This is a schematic diagram of the energy system in the energy release and power generation stage of this invention.

[0023] In the diagram: 1. Caprock, 2. Bottom plate boundary, 3. Aquifer, 4. Injection-production well, 5. Drainage well, 6. Injection well, 7. Surface reservoir, 8. Overlying geological layer, 9. Injection pipeline, 10. Gas purification and pressure regulating mechanism, 11. Surface gas storage tank, 12. Gas pump, 13. Solenoid valve, 14. Hydroelectric generator, 15. Energy management unit, 16. Elastic air cushion, 17. Reservoir tank, 18. Water pump, 19. Connecting pipeline, 20. Gas turbine, 21. Power module one, 22. Power module two, 23. Wind and solar power generation equipment, 24. Injection-production pipeline, 25. Drainage pipeline. Detailed Implementation

[0024] The invention will now be further described with reference to the accompanying drawings.

[0025] like Figures 1 to 3 As shown, the present invention provides an integrated energy system that couples aquifer gas storage and pumped storage, including a confined aquifer structure, an injection-production well network subsystem, a surface water and gas treatment and storage subsystem, and a power generation and energy management subsystem; The pressurized aquifer structure includes a bottom plate boundary 2 at the bottom, a capping layer 1 at the top of the bottom plate boundary 2, and an aquifer 3 between the bottom plate boundary 2 and the capping layer 1. The injection-production well network subsystem includes injection-production wells 4, drainage wells 5, water injection wells 6, injection-production pipelines 24, drainage pipelines 25, and water injection pipelines 9. Injection-production wells 4, drainage wells 5, and water injection wells 6 are all vertically arranged and distributed at intervals. The lower end of injection-production well 4 passes through the overlying geological layer 8 and the caprock 1 in sequence, ending at the top of the aquifer 3. The lower ends of drainage wells 5 and water injection wells 6 pass through the overlying geological layer 8 and the caprock 1 in sequence, ending at the bottom of the aquifer 3. The injection-production pipelines, drainage pipelines, and water injection pipelines are respectively fixedly inserted into injection-production wells 4, drainage wells 5, and water injection wells 6. Injection-production wells 4 are used to inject or extract natural gas into the aquifer 3; drainage wells 5 are used to drain water from the aquifer 3; and water injection wells 6 are used to reinject water from the surface reservoir 7 into the aquifer 3 to balance the pressure in the aquifer 3 during gas extraction. The ground water and air treatment and storage subsystem includes an injection and drainage mechanism and an injection and air release mechanism; the injection and drainage mechanism includes a ground reservoir 7, a water pump 18, a connecting pipeline 19, and a solenoid valve 13; the ground reservoir 7 includes a reservoir body 17 and an elastic air cushion 16, the elastic air cushion 16 covering the inner wall of the reservoir body 17, forming an elastic water storage space inside the elastic air cushion 16; the outlet of the water pump 18 is connected to the inlet of the ground reservoir 7, and its inlet is connected to the drainage pipeline. The upper end of 25 is connected; the connecting pipe 19 is connected to the outlet of the ground reservoir 7 and the upper end of the water injection pipe 9 respectively; the solenoid valve 13 is connected in series in the water inlet section of the connecting pipe 19; the air injection and exhaust mechanism includes a ground gas storage tank 11, a gas purification and pressure regulating mechanism 10 and an air pump 12; one working air port of the air pump 12 is connected to the gas interface of the ground gas storage tank 11 through the gas purification and pressure regulating mechanism 10, and the other working air port of the air pump 12 is connected to the upper end of the injection and extraction pipe 24; The power generation and energy management subsystem includes a power generation unit and an energy management unit 15. The power generation unit includes a hydro-generator 14, which is connected in series in the outlet section of the connecting pipeline 19. The energy management unit 15 is connected to the hydro-generator 14, a solenoid valve 13, a water pump 18, an air pump 12, and a gas purification and pressure regulating mechanism 10. The energy management unit 15 coordinates the flow of electricity, gas, and water, as well as the energy conversion process. As a preferred embodiment, the power generation unit further includes a gas turbine 20; the gas turbine 20 is connected to the gas purification and pressure regulating mechanism 10 via a gas pipeline.

[0026] As a preferred embodiment, the energy management unit 15 further includes a power module 21 and a power module 22; the power module 21 is connected to the water pump 18 and the water turbine generator 14 respectively; the power module 22 is connected to the air pump 12 and the gas turbine 20 respectively; at the same time, the power module 21 and the power module 22 are connected by an on / off control circuit.

[0027] As a preferred embodiment, the power generation unit further includes a wind and solar power generation device 23; the wind and solar power generation device 23 is connected to power module 1 21 and power module 22 respectively.

[0028] As a preferred embodiment, the energy management unit 15 further includes an inverter and a controller. The inverter is connected to power module 1 21, power module 2 22 and the local power grid, respectively. The controller is connected to the inverter, the hydro generator 14, the gas turbine 20, the solenoid valve 13, the water pump 18, the gas pump 12, the gas purification and pressure regulating mechanism 10 and the wind and solar power generation equipment 23, respectively.

[0029] As a preferred embodiment, the hydro-generator 14 is a reversible pump-turbine, so that it operates as a pump during periods of surplus power and as a turbine during periods of power demand.

[0030] In this invention, the lower end of the injection-production well terminates in the top space of the aquifer. This facilitates the injection or extraction of natural gas into the top space of the aquifer using the injection-production well. During injection, the continuously added natural gas provides pressure to the water surface, reducing the suction pressure on the water in the aquifer and improving suction efficiency. The lower ends of both the drainage well and the injection well terminate in the bottom space of the aquifer. This allows for efficient use of the pressure provided by the natural gas during injection to improve the water output efficiency of the drainage well. Furthermore, during extraction, the reinjection pressure from the injection well reduces the suction pressure during natural gas extraction, improving extraction efficiency. The installation of injection-production, drainage, and injection pipelines ensures that the entire gas injection and extraction process, as well as the injection and drainage process, is conducted in a sealed environment, preventing leakage that could reduce operational efficiency. Covering the inner surface of the reservoir tank with an elastic air cushion creates an elastic water storage space within the surface reservoir. During storage, when the water volume exceeds the normal capacity of this elastic space, the air cushion is effectively compressed, thus storing elastic energy. The gas purification and pressure regulating mechanism facilitates the purification and pressure regulation of extracted or injected natural gas, preventing dangerous gases from entering the surface gas storage facility or toxic gases from entering the aquifer. It also allows for the diversion of excess treated natural gas to a gas turbine for power generation during extraction. Solenoid valves on the connecting pipelines allow for convenient control of the pipeline's opening and closing. The branch containing the water pump and drainage pipeline, along with the branch containing the gas pump and injection / production pipeline, forms a coordinated gas injection and water pumping unit. Through their coordinated operation, water pumping can be performed simultaneously with natural gas injection into the aquifer, effectively balancing the pressure within the aquifer. The branch lines connecting the gas pump and water injection pipelines, along with the branch lines containing the gas pump and injection / production pipelines, form a coordinated unit for gas extraction, water injection, and power generation. Through their coordinated operation, while extracting natural gas, the negative pressure of the extraction, the elastic compression of the elastic air cushion, and the gravitational potential energy at a higher elevation are simultaneously applied to the water in the surface reservoir. This causes the water to flow out at high speed and efficiently drive the hydroelectric generator for power generation. Simultaneously, it effectively balances the pressure within the aquifer. The energy management unit facilitates intelligent coordination of the flow of electricity, gas, and water, as well as the energy conversion process.

[0031] This system has a simple structure and low investment cost. It is coupled and connected by a surface reservoir, a surface gas storage facility and an aquifer. It can not only use the aquifer as an underground gas storage facility for natural gas, but also make full use of the natural gas injection and extraction and water flow extraction and reinjection process to realize potential energy conversion and power generation. By making combined use of the aquifer, it realizes the mutual conversion and storage of electrical energy, pressure potential energy and water level potential energy, realizes the two core functions of power energy storage and natural gas energy storage, realizes the energy cascade utilization process, and systematically integrates power peak shaving, natural gas peak shaving and energy recovery and utilization into one, which has excellent economic and social benefits.

[0032] This invention also provides a comprehensive method for coupling aquifer gas storage and pumped hydro storage, employing a comprehensive energy system that couples aquifer gas storage and pumped hydro storage, comprising the following steps: Step 1: Layout of an integrated energy system that couples aquifer gas storage and pumped hydro storage; S11: Drill injection-production wells 4, drainage wells 5 and water injection wells 6 at intervals in the selected confined aquifer area, and make the lower ends of injection-production wells 4 terminate at the top of aquifer 3, and make the lower ends of drainage wells 5 and water injection wells 6 terminate at the bottom of aquifer 3, respectively. As a preferred option, injection-production well 4, drainage well 5 and water injection well 6 all adopt a multi-layer completion structure to achieve precise injection-production and isolation of specific sections of aquifer 3; S12: Install injection-production pipeline 24, drainage pipeline 25, and water injection pipeline 9 into injection-production well 4, drainage well 5, and water injection well 6 respectively; connect water injection pipeline 9 and surface reservoir 7 using connecting pipeline 19, and connect water turbine generator 14 and solenoid valve 13 in series on connecting pipeline 19; connect drainage pipeline 25 and surface reservoir 7 using water pump 18; connect injection-production pipeline 24 and surface gas storage 11 using the pipeline containing air pump 12 and gas purification and pressure regulating mechanism 10; S13: Establish connections between the controller and the inverter, hydro-generator 14, gas turbine 20, solenoid valve 13, water pump 18, air pump 12, gas purification and pressure regulating mechanism 10, and wind and solar power generation equipment 23; establish connections between the hydro-generator 14 and power module one 21, gas turbine 20, and power module two 22.

[0033] Step 2: When there is surplus wind and solar power or the local power grid load is low, control the air pump 12 and water pump 18 to start working synchronously. Use water pump 18 to extract water from the aquifer 3 and pump it into the elastic water storage space, ensuring that the water injection volume exceeds the normal capacity of the elastic storage space, so as to compress the elastic air cushion 16 to store elastic potential energy. At the same time, use air pump 12 to inject natural gas, which has been processed by the gas purification and pressure regulating mechanism 10, into the aquifer 3 through the injection and production pipeline 24 to maintain the pressure balance in the aquifer 3. Thus, the energy storage and charging operation is realized. Preferably, when there is a surplus of wind and solar power, the wind and solar power generation equipment 23 is controlled to generate electricity. At the same time, the generated electrical energy is stored in power module 1 21 or power module 22, or it can be stored in power module 1 21 and power module 22 in different time periods. When the local power grid load is low, the water pump 18 and air pump 12 are connected to the local power grid to provide electricity for the water pump 18 and air pump 12.

[0034] Step 3: During peak gas consumption, the gas pump 12 is started and the solenoid valve 13 is opened. The gas pump 12 extracts natural gas from the aquifer 3, which is then processed by the gas purification and pressure regulating mechanism 10 and injected into the surface gas storage tank 14. The natural gas is then supplied to users through the surface gas storage tank 14. Simultaneously, the negative pressure generated during the extraction process draws water from the elastic water storage space. At the same time, the elastic potential energy stored in the elastic air cushion 6 compresses the water in the elastic water storage space, and the high-level gravitational potential energy of the surface reservoir 7 acts on the water. Under the triple action of negative pressure extraction, elastic compression, and gravitational potential energy, the water flows out at high speed and is reinjected into the aquifer 3 through the water turbine generator 14 and the water injection pipeline 9. The water turbine generator 14 is driven to generate electricity, which is stored in the power module 21. Thus, the energy release and power generation operation is realized.

[0035] As a preferred option, an electromagnetic flow regulating valve one can be connected in series on the injection-production pipeline 24, and an electromagnetic flow regulating valve two can be connected in series on the water injection pipeline 9. The electromagnetic flow regulating valves one and two are respectively connected to the energy management unit 15, specifically, they can be connected to the controller. The energy management unit 15 adjusts the ratio of gas production and reinjection water by dynamically adjusting the electromagnetic flow regulating valves one and two, so as to effectively maintain the pressure in the aquifer 3 within a safe and stable range and maximize power generation revenue.

[0036] As a preferred embodiment, the injection-production well network subsystem also includes a monitoring well. The lower end of the monitoring well passes through the overlying geological layer 9 and the caprock 1 in sequence before entering the aquifer 3. It is used to monitor the migration of the gas-water interface in the aquifer 3, so as to enable intelligent management of the injection-production process through real-time monitoring and simulation, and to adjust the injection-production strategy in a timely manner to prevent gas escape and ensure the long-term operating efficiency of the gas storage facility.

[0037] As a preferred option, in step three, when the natural gas in the ground gas storage 14 meets the user's needs, the processed natural gas is transported to the gas turbine 20 for power generation through the gas purification and pressure regulating mechanism 10, and the generated electrical energy is stored in the power module 22.

[0038] To achieve energy conversion, in step three, when the power level in power module 1 21 or power module 22 exceeds the upper threshold, the inverter converts the DC power in power module 1 21 or power module 22 into AC power and outputs it to the local power grid. When the power level in power module 1 21 exceeds the upper threshold and the power level in power module 22 is less than the lower threshold, the on / off control circuit transfers the power from power module 1 21 to power module 22 to charge it. When the power level in power module 22 exceeds the upper threshold and the power level in power module 1 21 is less than the lower threshold, the on / off control circuit transfers the power from power module 22 to power module 1 21 to charge it.

[0039] This invention provides a comprehensive method that can synergistically absorb new energy sources, simultaneously solve the peak-shaving problems of electricity and gas, and achieve energy cascade utilization. During periods of surplus wind and solar power or low local grid load, the synchronous injection process using water and gas pumps not only injects natural gas into the aquifer, reducing the storage pressure of the surface gas storage facility, but also reduces the water extraction pressure in the aquifer through gas pressure, thus improving water extraction efficiency and effectively maintaining pressure balance within the aquifer. During the water injection process into the elastic water storage space, ensuring that the injected water volume exceeds the normal capacity of the elastic water storage space allows for effective compression of the elastic gas cushion, thereby ensuring the storage of a significant amount of elastic potential energy during this process. During peak gas demand periods, the extraction of natural gas creates negative pressure within the aquifer. Simultaneously, the elastic gas cushion stores elastic potential energy, and the surface reservoir possesses high gravitational potential energy relative to the aquifer. When the solenoid valve is opened, the triple action of negative pressure suction, elastic compression, and gravitational potential energy causes water to flow out at high speed, efficiently driving a hydroelectric generator for high-efficiency power generation. The generated electricity can be directly stored or supplied to other electrical equipment or fed into the local power grid as needed. Furthermore, the simultaneous reinjection during gas extraction effectively replenishes formation pressure, avoiding the instability issues such as sand production and formation deformation that can occur with traditional underground gas storage facilities due to rapid pressure drops, thus improving the stability and safety of the gas storage operation.

[0040] This invention creates a closed-loop system by coordinating a surface reservoir, a surface gas storage facility, an underground aquifer, pipelines, and pumps, with the underground serving as the gas storage facility, the surface as the reservoir, and the wellbore as the power generation channel. It can utilize the aquifer to store gas and store energy, solve the problem of peak gas demand during the gas extraction process, and at the same time, make full use of the water reinjected into the aquifer for efficient power generation. Simultaneously, it can balance the pressure of the aquifer to ensure the efficient operation of gas extraction.

[0041] This method enables the mutual conversion and storage of electrical energy, pressure potential energy, and water level potential energy. It effectively recovers the potential energy wasted in the water injection / extraction process in traditional aquifer gas storage facilities and converts it into electrical energy, thereby improving overall energy efficiency, realizing the recycling of energy, promoting the consumption of new energy sources through the recycling process, providing a large-scale, long-term energy storage outlet for surplus wind and solar power, and smoothing grid load fluctuations through power generation, thus significantly improving economic benefits and social efficiency.

Claims

1. A comprehensive energy system coupling aquifer gas storage and pumped-storage, comprising a confined aquifer structure, wherein the confined aquifer structure includes a bottom plate boundary (2) at the lower part, a capping layer (1) at the upper end of the bottom plate boundary (2), and an aquifer (3) located between the bottom plate boundary (2) and the capping layer (1); characterized in that, It also includes an injection-production well network subsystem, a surface water and gas treatment and storage subsystem, and a power generation and energy management subsystem; The injection-production well network subsystem includes injection-production wells (4), drainage wells (5), water injection wells (6), injection-production pipelines (24), drainage pipelines (25), and water injection pipelines (9). The injection-production wells (4), drainage wells (5), and water injection wells (6) are all vertically arranged and distributed in sequence at intervals. The lower end of the injection-production well (4) passes through the overlying geological layer (8) and the caprock (1) in sequence and ends at the top of the aquifer (3). The lower ends of the drainage wells (5) and the water injection wells (6) pass through the overlying geological layer (8) and the caprock (1) in sequence and end at the bottom of the aquifer (3). The injection-production pipelines (24), drainage pipelines (25), and water injection pipelines (9) are respectively fixedly inserted into the injection-production wells (4), drainage wells (5), and water injection wells (6). The ground water and air treatment and storage subsystem includes an injection and drainage mechanism and an injection and air release mechanism; the injection and drainage mechanism includes a ground reservoir (7), a water pump (18), a connecting pipeline (19), and a solenoid valve (13); the ground reservoir (7) includes a reservoir body (17) and an elastic air cushion (16), the elastic air cushion (16) covering the inner wall of the reservoir body (17), forming an elastic water storage space inside the elastic air cushion (16); the outlet of the water pump (18) is connected to the inlet of the ground reservoir (7), and its inlet is connected to the drainage pipeline (2). 5) The upper end is connected; the connecting pipe (19) is connected to the outlet of the ground reservoir (7) and the upper end of the water injection pipe (9) respectively; the solenoid valve (13) is connected in series in the water inlet section of the connecting pipe (19); the air injection and exhaust mechanism includes a ground gas storage tank (11), a gas purification and pressure regulating mechanism (10) and an air pump (12); one working air port of the air pump (12) is connected to the gas interface of the ground gas storage tank (11) through the gas purification and pressure regulating mechanism (10), and the other working air port of the air pump (12) is connected to the upper end of the injection and extraction pipe (24); The power generation and energy management subsystem includes a power generation unit and an energy management unit (15); the power generation unit includes a hydro-generator (14), which is connected in series in the outlet section of the connecting pipeline (19); the energy management unit (15) is connected to the hydro-generator (14), the solenoid valve (13), the water pump (18), the air pump (12) and the gas purification and pressure regulating mechanism (10) respectively.

2. The integrated energy system coupling aquifer gas storage and pumped hydro storage according to claim 1, characterized in that, The power generation unit also includes a gas turbine (20); the gas turbine (20) is connected to a gas purification and pressure regulating mechanism (10) through a gas pipeline.

3. The integrated energy system coupling aquifer gas storage and pumped hydro storage according to claim 2, characterized in that, The energy management unit (15) also includes a power module one (21) and a power module two (22); the power module one (21) is connected to the water pump (18) and the water turbine generator (14) respectively; the power module two (22) is connected to the air pump (12) and the gas turbine (20) respectively; at the same time, the power module one (21) and the power module two (22) are connected through a switchable control circuit.

4. The integrated energy system coupling aquifer gas storage and pumped hydro storage according to claim 3, characterized in that, The power generation unit also includes a wind and solar power generation device (23); the wind and solar power generation device (23) is connected to power module one (21) and power module two (22) respectively.

5. The integrated energy system coupling aquifer gas storage and pumped hydro storage according to claim 4, characterized in that, The energy management unit (15) also includes an inverter and a controller. The inverter is connected to power module one (21), power module two (22) and the local power grid respectively. The controller is connected to the inverter, the hydro generator (14), the gas turbine (20), the solenoid valve (13), the water pump (18), the gas pump (12), the gas purification and pressure regulating mechanism (10) and the wind and solar power generation equipment (23).

6. The integrated energy system coupling aquifer gas storage and pumped hydro storage according to claim 1, characterized in that, The water turbine generator (14) is a reversible water pump turbine.

7. A comprehensive method for coupling aquifer gas storage and pumped hydro storage, employing a comprehensive energy system for coupling aquifer gas storage and pumped hydro storage as described in any one of claims 1 to 6, characterized in that, Includes the following steps: Step 1: Layout of an integrated energy system that couples aquifer gas storage and pumped hydro storage; Step 2: When there is a surplus of wind and solar power or when the local power grid load is low, control the air pump (12) and water pump (18) to start working simultaneously. Use the water pump (18) to extract water from the aquifer (3) and pump it into the elastic water storage space to ensure that the water injection volume exceeds the normal capacity of the elastic storage space, so as to compress the elastic air cushion (16) to store elastic potential energy. At the same time, use the air pump (12) to inject natural gas processed by the gas purification and pressure regulating mechanism (10) into the aquifer (3) through the injection and production pipeline (24) to maintain the pressure balance in the aquifer (3). Step 3: During peak gas demand, control the gas pump (12) to start working and control the solenoid valve (13) to open. Use the gas pump (12) to extract natural gas from the aquifer (3) and add it to the ground gas storage tank (14) after processing by the gas purification and pressure regulating mechanism (10). At the same time, the combined effect of the negative pressure generated during the gas extraction process, the elastic potential energy stored in the elastic air cushion (6), and the high-level gravitational potential energy of the ground reservoir (7) causes the water to flow out at high speed and be reinjected into the aquifer (3) through the water turbine generator (14) and the water injection pipeline (9). Simultaneously drive the water turbine generator (14) to generate electricity and store the generated electrical energy in the power module (21).

8. The integrated method for coupling aquifer gas storage and pumped hydro storage according to claim 7, characterized in that, In step two, when there is a surplus of wind and solar power, the wind and solar power generation equipment (23) is controlled to generate electricity and the generated electricity is stored in power module one (21) or power module two (22). When the local power grid load is low, the water pump (18) and the air pump (12) are connected to the local power grid respectively to facilitate the supply of electricity to the water pump (18) and the air pump (12).

9. The integrated method for coupling aquifer gas storage and pumped hydro storage according to claim 8, characterized in that, In step three, when the natural gas in the ground gas storage (14) meets the user's needs, the processed natural gas is transported to the gas turbine (20) through the gas purification and pressure regulating mechanism (10) for power generation, and the generated electrical energy is stored in the power module two (22).

10. A comprehensive method for coupling aquifer gas storage and pumped hydro storage according to claim 8, characterized in that, In step three, when the amount of electricity in power module one (21) or power module two (22) is greater than the upper limit threshold, the inverter is used to convert the DC power in power module one (21) or power module two (22) into AC power and output it to the local power grid; when the amount of electricity in power module one (21) is greater than the upper limit threshold and the amount of electricity in power module two (22) is less than the lower limit threshold, the on / off control circuit is used to transfer the electrical energy in power module one (21) to power module two (22) to charge power module two (22); when the amount of electricity in power module two (22) is greater than the upper limit threshold and the amount of electricity in power module one (21) is less than the lower limit threshold, the on / off control circuit is used to transfer the electrical energy in power module two (22) to power module one (21) to charge power module one (21).

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