Hybrid energy storage method and system based on waste oil and gas well compressed fluid and chemical energy storage

Abstract

The invention relates to a mixed energy storage method and system based on waste oil and gas well compressed fluid and chemical energy storage. The method comprises the steps that a waste oil and gas well is selected; establishing a connecting channel between the ground and the waste oil-gas well; the electrolyte of the flow battery is injected into a waste oil-gas well by utilizing wind-light waste electricity, and abandoned wind and abandoned electricity are converted into mechanical energy; the electrolyte is discharged into the hydro-generator through high voltage in the waste oil and gas well, the hydro-generator generates electricity under the action of the electrolyte, and mechanical energy is converted into electric energy; the hydraulic generator conveys the electrolyte into the flow battery at a set flow rate for electrochemical energy storage; and the electrolyte flowing out of the flow battery circularly enters the waste oil-gas well, and the steps are repeated to complete the mixed energy storage of the compressed fluid and the chemical energy storage based on the waste oil-gas well. The waste oil and gas well is utilized, combined application of the flow battery and compressed fluid energy storage is achieved, meanwhile, pump consumption of the flow battery is eliminated, cost is saved, and the working efficiency of the whole energy storage system is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of energy storage and power generation, and in particular to a hybrid energy storage method and system based on compressed fluid of abandoned oil and gas wells and chemical energy storage. Background Art

[0002] Energy storage refers to the process of storing energy through a medium or device and releasing it when needed. Energy storage can improve energy utilization efficiency, enhance the stability of the power system, and quickly provide backup power when the power grid fails or blackouts, ensuring uninterrupted power supply to important loads and improving the reliability and stability of the power system. Improving the economic efficiency of renewable energy power generation can reduce the phenomenon of wind and solar power abandonment caused by the intermittent nature of renewable energy, improve the economic benefits and return on investment of renewable energy power generation projects, and promote the sustainable development of the renewable energy industry.

[0003] Abandonment of wind power and electricity, namely wind power curtailment and photovoltaic power curtailment, refers to the phenomenon that during the process of wind power generation and photovoltaic power generation, due to various reasons, some wind power and photovoltaic power cannot be connected to the grid for transmission, thus being wasted. Wind power and photovoltaic power generation are characterized by intermittency, randomness and instability. After large-scale wind power and photovoltaic power are connected to the grid, higher requirements are placed on the peak-shaving, frequency-regulating and voltage-regulating capabilities of the grid. Abandonment of wind power and electricity avoids energy waste, converts clean energy such as wind power and photovoltaic power that was originally discarded into usable energy forms, improves the overall efficiency of energy utilization, and makes fuller use of limited energy resources.

[0004] Hydraulic energy storage is a technology that uses the incompressible property of liquids to convert excess electrical energy or other forms of energy into hydraulic energy for storage, and then converts hydraulic energy into other forms of energy when needed. However, the investment cost of hydraulic energy storage equipment is relatively high, including the purchase and installation costs of energy storage devices, hydraulic pumps, hydraulic motors, control systems and other equipment, which to a certain extent limits its large-scale promotion and application. Liquid flow batteries are an electrochemical energy storage technology that achieves the mutual conversion of electrical energy and chemical energy through reversible redox reactions of active substances in positive and negative electrolyte solutions. However, the pumping system in the liquid flow battery energy storage system consumes a certain amount of energy to drive the circulation of the electrolyte, which will reduce the overall working efficiency of the battery and increase operating costs.

[0005] At the same time, abandoned oil and gas wells are difficult to manage, and their long-term idleness will lead to a series of chain reactions. It is urgent to adopt effective measures to manage abandoned oil and gas wells.

[0006] Therefore, the inventor, relying on many years of experience and practice in related industries, proposes a hybrid energy storage method and system based on compressed fluid of abandoned oil and gas wells and chemical energy storage to overcome the defects of the prior art. Summary of the invention

[0007] The purpose of the present invention is to provide a hybrid energy storage method and system based on compressed fluid and chemical energy storage in abandoned oil and gas wells, which utilizes abandoned oil and gas wells to achieve the combined application of flow batteries and compressed fluid energy storage, while eliminating the pump consumption of flow batteries, saving costs and improving the working efficiency of the entire energy storage system.

[0008] The object of the present invention is achieved by a hybrid energy storage method based on compressed fluid and chemical energy storage in abandoned oil and gas wells, comprising the following steps:

[0009] Step S1, selecting at least one abandoned oil and gas well;

[0010] Step S2, establishing a connection channel between the ground and the abandoned oil and gas well, including a fluid injection channel and a fluid discharge channel; the bottom end of the fluid injection channel is located in the sealed and waterproof abandoned oil and gas well, and the bottom end of the fluid discharge channel is set lower than the bottom end of the fluid injection channel; the top outlet of the fluid discharge channel is connected to the hydro-generator and the flow battery;

[0011] Step S3, using the wind and solar power waste electricity to inject a set volume of electrolyte of the flow battery into the abandoned oil and gas well through the fluid injection channel; converting the abandoned wind and solar power into mechanical energy to complete the compressed fluid energy storage;

[0012] Step S4, the high pressure in the abandoned oil and gas well discharges the electrolyte into the hydro-generator through the fluid discharge channel, and the hydro-generator generates electricity under the action of the electrolyte, converting mechanical energy into electrical energy;

[0013] Step S5, the hydro-generator delivers the electrolyte to the flow battery at a set flow rate to maintain the operation of the flow battery and perform electrochemical energy storage;

[0014] Step S6: The electrolyte flowing out of the flow battery can be circulated into the abandoned oil and gas well, and steps S3-S5 are repeated to complete the mixed energy storage of compressed fluid and chemical energy storage based on the abandoned oil and gas well.

[0015] In a preferred embodiment of the present invention, in step S6, the outlet of the liquid flow battery is connected to the inlet of the buffer tank, and the outlet of the buffer tank can be connected to the fluid injection channel; the electrolyte flowing through the liquid flow battery is once again pressed into the abandoned oil and gas well through the buffer tank.

[0016] In a preferred embodiment of the present invention, in step S6, the outlet of the liquid flow battery or the outlet of the buffer tank is connected to a liquid storage tank; when the wind and solar waste electricity is insufficient, the electrolyte flowing through the liquid flow battery flows into the liquid storage tank for storage.

[0017] In a preferred embodiment of the present invention, in step S3, an electric liquid injection device is provided at the top of the fluid injection channel, and the electric liquid injection device is supplied with electric energy by wind and solar waste electricity.

[0018] In a preferred embodiment of the present invention, in step S5, a pressure sensing device is provided at the electrolyte outlet of the hydro-turbine generator, and the pressure sensing device reacts to the hydro-turbine generator by sensing the liquid flow pressure value of the electrolyte, thereby adjusting the power of the hydro-turbine generator so that the electrolyte flows into the flow battery at a set flow rate.

[0019] In a preferred embodiment of the present invention, in step S2, a sealed and waterproof underground high-pressure storage space is provided in the abandoned oil and gas well, and the bottom ends of the fluid injection channel and the fluid discharge channel are located in the underground high-pressure storage space; the underground high-pressure storage space is a single independent space body or a group of interconnected space bodies; the depth range of the underground high-pressure storage space is 0 to 20,000 m below the ground.

[0020] In a preferred embodiment of the present invention, the distance between the bottom ends of the fluid injection channel and the fluid discharge channel and the bottom surface of the underground high-pressure storage space is 1 to 50 m.

[0021] In a preferred embodiment of the present invention, in step S2, when the air pressure in the underground high-pressure storage space is greater than or equal to the set pressure, a waterproof layer is applied in the underground high-pressure storage space.

[0022] In a preferred embodiment of the present invention, in step S2, when the air pressure in the underground high-pressure storage space is lower than the set pressure, a waterproof layer and a sealing layer are applied to the underground high-pressure storage space, and gas is injected into the abandoned oil and gas well to enhance the air pressure in the underground high-pressure storage space.

[0023] In a preferred embodiment of the present invention, in step S2, one of the abandoned oil and gas wells is connected to one of the liquid flow batteries, or one of the abandoned oil and gas wells is connected to multiple of the liquid flow batteries, or one of the liquid flow batteries is connected to multiple of the abandoned oil and gas wells.

[0024] The purpose of the present invention can also be achieved in this way: a hybrid energy storage system based on compressed fluid and chemical energy storage of abandoned oil and gas wells, used in the aforementioned hybrid energy storage method based on compressed fluid and chemical energy storage of abandoned oil and gas wells;

[0025] The hybrid energy storage system based on abandoned oil and gas well compressed fluid and chemical energy storage includes:

[0026] At least one abandoned oil and gas well;

[0027] At least 1 hydroelectric generator;

[0028] At least one surface-mounted flow battery;

[0029] At least one group of connecting channels, one group of connecting channels includes at least one fluid injection channel and at least one fluid discharge channel; the bottom end of the fluid injection channel is located in the abandoned oil and gas well, the bottom end of the fluid discharge channel is located in the abandoned oil and gas well, and the bottom end of the fluid discharge channel is arranged lower than the bottom end of the fluid injection channel; the top outlet of the fluid discharge channel is sequentially connected to the hydro-generator and the flow battery; the outlet of the flow battery can be connected to the top of the fluid injection channel; the top of the fluid injection channel is connected to an electric injection device supplied with electric energy by wind and solar waste electricity.

[0030] As described above, the hybrid energy storage method and system based on abandoned oil and gas well compressed fluid and chemical energy storage of the present invention has the following beneficial effects:

[0031] The present invention utilizes abandoned oil and gas wells to realize the combined application of liquid flow batteries and compressed fluid energy storage, eliminates liquid flow battery pump consumption, improves the working efficiency of the energy storage system, effectively solves the problem of storage and utilization of excess renewable energy electricity, increases energy storage capacity and recovery efficiency, and enhances the utilization value of abandoned oil and gas wells. It provides a new path for stable power supply of the power grid, is conducive to solving the problems of mismatch between electricity supply and demand and new energy power generation and consumption, and realizes efficient storage, stable supply and full utilization of electricity. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The following drawings are only intended to illustrate and explain the present invention, and are not intended to limit the scope of the present invention.

[0033] in:

[0034] Figure 1 It is a schematic diagram of Example 1 of the present invention.

[0035] Figure 2 This is a schematic diagram of Example 2 of the present invention.

[0036] Figure 3 This is a schematic diagram of Example 3 of the present invention.

[0037] Figure 4 It is a schematic diagram of Example 4 of the present invention.

[0038] In the figure:

[0039] 1. Abandoned oil and gas wells;

[0040] 21. Fluid injection channel; 22. Fluid discharge channel;

[0041] 3. Hydro-generator;

[0042] 4. Liquid flow battery; 41. Positive electrode flow channel; 42. Negative electrode flow channel;

[0043] 5. Electric power injection equipment;

[0044] 6. Pressure sensing device;

[0045] 7. Buffer tank;

[0046] 8. Liquid storage tank; 81. Liquid storage tank valve. DETAILED DESCRIPTION

[0047] In order to have a clearer understanding of the technical features, purposes and effects of the present invention, specific embodiments of the present invention are now described with reference to the accompanying drawings.

[0048] The specific embodiments of the present invention described herein are only used to explain the purpose of the present invention and cannot be understood as limiting the present invention in any way. Under the guidance of the present invention, technicians can conceive of any possible variations based on the present invention, which should be considered to belong to the scope of the present invention. It should be noted that when an element is referred to as "arranged on" another element, it can be directly on the other element or there can also be a central element. When an element is considered to be "connected" to another element, it can be directly connected to the other element or there may be a central element at the same time. The terms "installed", "connected" and "connected" should be understood in a broad sense, for example, it can be a mechanical connection or an electrical connection, or it can be the internal communication of two elements, it can be directly connected, or it can be indirectly connected through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to the specific circumstances. The terms "vertical", "horizontal", "up", "down", "left", "right" and similar expressions used herein are only for illustrative purposes and do not represent the only implementation method.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those generally understood by those skilled in the art to which this application belongs. The terms used herein in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0050] The present invention provides a hybrid energy storage method based on compressed fluid and chemical energy storage in abandoned oil and gas wells, comprising the following steps:

[0051] Step S1, selecting at least one abandoned oil and gas well 1;

[0052] Step S2, establishing a connection channel between the ground and the abandoned oil and gas well 1, including a fluid injection channel 21 and a fluid discharge channel 22; the bottom end of the fluid injection channel 21 is located in the sealed and waterproof abandoned oil and gas well 1, and the bottom end of the fluid discharge channel 22 is set lower than the bottom end of the fluid injection channel 21; the top outlet of the fluid discharge channel 22 is connected to the hydro-generator 3 and the flow battery 4;

[0053] Specifically:

[0054] In step S2, a sealed and waterproof underground high-pressure storage space (underground high-pressure storage tank body) is provided in the abandoned oil and gas well 1, and the bottom ends of the fluid injection channel 21 and the fluid discharge channel 22 are located in the underground high-pressure storage space; the underground high-pressure storage space is a single independent space body or a group of interconnected space bodies; the depth range of the underground high-pressure storage space is 0 to 20,000 m below the ground, preferably 500 to 5,000 m below the ground.

[0055] The connection channel between the ground and the underground high-pressure storage space of the abandoned oil and gas well is two fluid communication channels (fluid injection channel 21 and fluid discharge channel 22), which are used for injection and discharge of electrolyte respectively;

[0056] The connecting channels all meet the air-tight requirements, and the bottom end (underground outlet) of the fluid injection channel 21 and the bottom end (underground inlet) of the fluid discharge channel are 1 to 50 m away from the bottom surface of the underground high-pressure storage space, and the distance is preferably 3 to 10 m.

[0057] Furthermore, in step S2, when the gas pressure in the underground high-pressure storage space (which can be regarded as a high-pressure storage tank body) is greater than or equal to the set pressure (the set pressure is at least the pressure that can press the electro-hydraulic pressure to the ground), the underground high-pressure storage space is coated with a waterproof layer. That is, if the gas pressure in the underground high-pressure storage space is sufficient, only part of the waterproof layer can be coated to prevent liquid leakage.

[0058] When the air pressure in the underground high-pressure storage space is lower than the set pressure (the air pressure is not enough to squeeze out the electrolyte), a waterproof layer and a sealing layer are applied to the underground high-pressure storage space, and gas is pumped into the abandoned oil and gas well to increase the air pressure in the underground high-pressure storage space. The injected gas is a gas that will not affect the airtightness requirements of the underground high-pressure storage space and will not affect the electrolyte of the flow battery, such as one or more of nitrogen, helium, carbon dioxide, air, argon or other gases.

[0059] As a specific embodiment, the present invention can adopt a variety of connection channel forms, such as one abandoned oil and gas well corresponding to one liquid flow battery, or one abandoned oil and gas well corresponding to multiple liquid flow batteries, or one liquid flow battery corresponding to multiple abandoned oil and gas wells.

[0060] If the space of an abandoned oil and gas well 1 is too large, it can be separated by partitions or walls and sealed into multiple underground high-pressure storage tanks for use. The positive and negative electrolytes cannot contact each other, so adjacent underground high-pressure storage tanks are sealed and separated from each other.

[0061] Step S3, using the wind and solar power waste electricity to inject a set volume of electrolyte of the flow battery into the abandoned oil and gas well 1 through the fluid injection channel 21; converting the abandoned wind and solar power into mechanical energy to complete the compressed fluid energy storage;

[0062] Specifically, an electric liquid injection device 5 is provided at the top of the fluid injection channel 21, and the electric liquid injection device 5 is supplied with electric energy by wind and solar waste electricity.

[0063] Waste electricity from wind and solar power comes from systems that provide electricity such as wind power, solar power, and grid off-peak power.

[0064] This step can effectively consume excess photovoltaic and wind power, while providing energy for the electrolyte transportation of the flow battery, achieving full utilization and stable supply of electrical energy.

[0065] Step S4, the high pressure in the abandoned oil and gas well 1 discharges the electrolyte into the hydro-generator 3 through the fluid discharge channel 22, and the hydro-generator 3 generates electricity under the action of the electrolyte, converting mechanical energy into electrical energy;

[0066] Step S5, the hydro-generator 3 delivers the electrolyte to the flow battery 4 (the positive electrode flow channel 41 or the negative electrode flow channel 42) at a set flow rate to maintain the operation of the flow battery and perform electrochemical energy storage;

[0067] Specifically, a pressure sensor 6 is provided at the electrolyte outlet of the hydro-generator 3. The pressure sensor 6 senses the flow pressure value of the electrolyte and reacts to the hydro-generator 3 to adjust the power of the hydro-generator 3 so that the electrolyte flows into the flow battery 4 at a set flow rate.

[0068] The power of the hydro-generator 3 is adjusted to ensure that the flow rate of the electrolyte flowing into the flow battery 4 is stable, so that the flow battery 4 can operate stably; and the delivery of the hydro-generator 3 eliminates the pump consumption of the flow battery 4.

[0069] Step S6: The electrolyte flowing out of the liquid flow battery 4 can be circulated into the abandoned oil and gas well 1, and steps S3-S5 are repeated to complete the mixed energy storage of compressed fluid and chemical energy storage based on the abandoned oil and gas well.

[0070] Specifically, the outlet of the flow battery 4 is connected to the inlet of the buffer tank 7, and the outlet of the buffer tank 7 can be connected to the fluid injection channel 21; the electrolyte flowing through the flow battery 4 is once again pressed into the abandoned oil and gas well 1 through the buffer tank 7. When the electrolyte is pressed into the abandoned oil and gas well 1, the electrolyte will flow through the buffer tank 7, in order to make the liquid flow more stable and reduce the impact loss of the liquid on the electric injection equipment 5.

[0071] The outlet of the liquid flow battery 4 or the outlet of the buffer tank 7 is connected to the liquid storage tank 8; when the wind and solar waste electricity is insufficient, the electrolyte flowing through the liquid flow battery 4 flows into the liquid storage tank 8 for storage.

[0072] A liquid storage tank valve 81 is provided on the liquid storage tank 8. When the wind and solar power waste electricity is insufficient, the liquid storage tank valve 81 is opened, and the electrolyte flowing out of the flow battery 4 flows into the liquid storage tank 8 for temporary storage.

[0073] The electric energy stored by the present invention can be used in power grids, microgrids, industrial electricity, etc.

[0074] The present invention utilizes abandoned oil and gas wells to realize the combined application of liquid flow batteries and compressed fluid energy storage, while eliminating the pump consumption of the liquid flow batteries and improving the working efficiency of the entire energy storage system.

[0075] The present invention utilizes abandoned oil and gas wells to realize the combined application of liquid flow batteries and compressed fluid energy storage, eliminates liquid flow battery pump consumption, improves the working efficiency of the energy storage system, effectively solves the problem of storage and utilization of excess renewable energy electricity, increases energy storage capacity and recovery efficiency, and enhances the utilization value of abandoned oil and gas wells. It provides a new path for stable power supply of the power grid, is conducive to solving the problems of mismatch between electricity supply and demand and new energy power generation and consumption, and realizes efficient storage, stable supply and full utilization of electricity.

[0076] The present invention also provides a hybrid energy storage system based on compressed fluid and chemical energy storage of abandoned oil and gas wells, which is used in the aforementioned hybrid energy storage method based on compressed fluid and chemical energy storage of abandoned oil and gas wells;

[0077] The hybrid energy storage system based on compressed fluid and chemical energy storage of abandoned oil and gas wells includes:

[0078] At least 1 abandoned oil and gas well1;

[0079] At least one hydroelectric generator 3;

[0080] At least one liquid flow battery 4 disposed on the ground;

[0081] At least one group of connecting channels, one group of connecting channels includes at least one fluid injection channel 21 and at least one fluid discharge channel 22; the bottom end of the fluid injection channel 21 is located in the abandoned oil and gas well 1, the bottom end of the fluid discharge channel 22 is located in the abandoned oil and gas well 1, and the bottom end of the fluid discharge channel 22 is arranged lower than the bottom end of the fluid injection channel 21; the top outlet of the fluid discharge channel 22 is connected to the hydro-generator 3 and the liquid flow battery 4 in sequence; the outlet of the liquid flow battery 4 can be connected to the top of the fluid injection channel 21; the top of the fluid injection channel 21 is connected to the electric injection equipment 5 supplied with electric energy by wind and solar waste electricity.

[0082] The present invention utilizes abandoned oil and gas wells to realize hybrid energy storage of compressed fluid energy storage and chemical energy storage, creatively solving the problem of storage and utilization of excess renewable energy power (wind power and photovoltaic power generation). By injecting electrolyte into abandoned oil and gas wells, the energy storage capacity is increased, and efficient energy recovery is achieved through the hydro-turbine generator set, promoting the conversion of mechanical energy into electrical energy. In addition, this system significantly improves the overall energy efficiency by reducing dependence on electric injection equipment and pump consumption of liquid flow batteries. The present invention also increases the stability and reliability of liquid flow batteries, allowing them to maintain continuous operation when there is no wind and solar power supply. In general, the present invention provides an environmentally friendly and economical solution, effectively improving the utilization value of abandoned oil and gas wells, while providing a new technical path for the stable power supply of the power grid.

[0083] Example 1: Figure 1 As shown, the abandoned oil and gas well 1 needs to be pressurized by injecting gas, and the positive and negative electrodes of a flow battery 4 correspond to an abandoned oil and gas well 1, that is, the well needs to be gasified and cannot spray by itself, a one-to-one situation:

[0084] (1) Two abandoned oil and gas wells 1 that cannot self-flow are selected, with a depth range of 1200-1210m. After the waterproof layer and sealing layer are applied inside, they have gas and liquid sealing conditions to form two underground high-pressure storage tanks (i.e., two underground high-pressure storage spaces), one as a positive electrode electrolyte storage tank and the other as a negative electrode electrolyte storage tank.

[0085] (2) A Φ241.5 mm liquid inlet airtight casing (forming the fluid injection channel 21) and a Φ177.5 mm liquid outlet airtight casing (forming the fluid discharge channel 22) are inserted into the oil and gas well between the ground and the underground high-pressure storage tank body, and the depth of the casing mouth is 1200 m.

[0086] (3) Through on-site ground stress analysis and testing, it was determined that the rupture stress of the high-pressure storage tank body was 30.2 MPa, the internal upper limit pressure of the high-pressure storage tank body after compression was set to 18 MPa, and the internal upper limit pressure of the liquid flow battery after the electrolyte was injected into the tank body was set to 22 MPa.

[0087] (4) Use the abandoned photovoltaic power that is difficult to connect to the power grid to start the gas compressor, pressurize the high-pressure nitrogen into the underground high-pressure storage tank through the liquid-tight casing, strictly control the internal pressure to close to 18MPa by the gas injection volume, and stop the gas injection.

[0088] (5) Use the abandoned photovoltaic power that is difficult to integrate into the power grid to start the liquid pump, and transport the liquid flow battery electrolyte to the underground high-pressure storage tank through the liquid inlet airtight casing. As the liquid flow battery electrolyte is injected, the internal pressure of the underground high-pressure storage tank rises, and the nitrogen in the high-pressure storage tank is compressed. When the internal pressure of the high-pressure storage tank is about to reach 22MPa, the liquid outlet airtight casing is opened. Due to the high pressure of the abandoned oil and gas wells, the liquid flow battery electrolyte is squeezed into the liquid outlet airtight casing by the internal air pressure, and gradually flows upward into the liquid flow battery circulation pipeline.

[0089] (6) A turbine system (hydraulic generator 3) is provided between the surface outlet and the circulation pipeline of the single flow battery system to drive the turbine system to generate electricity and complete the mechanical energy storage process. The flow rate of the electrolyte at the outlet casing (the outlet of the fluid discharge channel 22) is adjusted by the hydraulic generator 3, and the flow rate at the inlet (the top inlet of the fluid injection channel 21) is adjusted by the liquid pump, so as to adjust the total volume of the liquid in the underground high-pressure storage tank body to be stable within a certain range, maintain the internal pressure of the tank body at 30MPa, and form a dynamic balance of the underground high-pressure storage tank body system.

[0090] (7) Start a single liquid flow battery system to perform a normal charge and discharge cycle. At the same time, the electrolyte will flow into the liquid flow battery after passing through the hydro-generator 3 to maintain the stable operation of the liquid flow battery 4, completing the electrochemical energy storage process. The electrolyte flowing through the liquid flow battery is once again pressed into the abandoned oil and gas well 1 through the buffer tank 7 to repeat the above process for circulation, and according to the actual photovoltaic power generation, the flow of the electrolyte in the pipeline is accelerated or slowed down, and the operation of the liquid flow battery is adjusted by feedback regulation.

[0091] Example 2: Figure 2 As shown, the abandoned oil and gas well 1 does not need to be injected with gas, and the positive and negative electrodes of a liquid flow battery 4 correspond to an abandoned oil and gas well 1, that is, no gas is added, it can be self-spraying, and it is a one-to-one situation:

[0092] (1) Two abandoned eruptive oil and gas wells were selected, with a depth range of 2300-2400m. After the waterproof layer and sealing layer were applied inside, they had gas and liquid sealing conditions, forming two underground high-pressure storage tanks, one as the positive electrode electrolyte storage tank and the other as the negative electrode electrolyte storage tank.

[0093] (2) A Φ273 mm liquid inlet airtight casing (forming the fluid injection channel 21) and a Φ197.5 mm liquid outlet airtight casing (forming the fluid discharge channel 22) are inserted into the oil and gas well between the ground and the underground high-pressure storage tank body. The depth of the casing mouth is 2350 m.

[0094] (3) Through on-site ground stress analysis and testing, it was determined that the rupture stress of the underground high-pressure storage tank body was 39.8 MPa.

[0095] (4) Use the abandoned wind power that is difficult to integrate into the power grid to start the liquid pump and transport the electrolyte of the flow battery through the liquid inlet airtight casing to the underground high-pressure storage tank. As the liquid flow battery electrolyte is injected, the internal pressure of the underground high-pressure storage tank rises. Open the liquid outlet airtight casing. Due to the high pressure of the abandoned oil and gas wells, the electrolyte of the liquid flow battery is squeezed into the liquid outlet airtight casing by the internal pressure and gradually flows upward into the circulation pipeline of the liquid flow battery.

[0096] (5) A set of water turbine system (water turbine generator 3) is arranged between the surface outlet pipe and the circulation pipeline of the flow battery system, which drives the water turbine system to generate electricity and completes the mechanical energy storage process. The water turbine generator 3 is used to adjust the electrolyte flow rate of the outlet casing, and the liquid pump at the liquid inlet is used to adjust the flow rate of the liquid inlet, so as to adjust the total volume of liquid in the underground high-pressure storage tank body to be stable within a certain range, and the underground high-pressure storage tank body system forms a dynamic balance.

[0097] (6) Start a single liquid flow battery system to perform a normal charge and discharge cycle. At the same time, the electrolyte will flow into the liquid flow battery after passing through the hydro-generator to maintain the stable operation of the liquid flow battery and complete the electrochemical energy storage process. The electrolyte flowing through the liquid flow battery 4 is once again pressed into the abandoned oil and gas well through the buffer tank 7 to repeat the above process for circulation, and according to the actual photovoltaic power generation, the flow of the electrolyte in the pipeline is accelerated or slowed down, and the operation of the liquid flow battery is adjusted by feedback regulation.

[0098] Example 3: Figure 3 As shown, the abandoned oil and gas well 1 needs to be pressurized by injecting gas, and the positive and negative electrodes of a flow battery 4 correspond to two abandoned oil and gas wells 1, that is, the wells need to be gasified and cannot be self-flowing, which is a one-to-many situation:

[0099] (1) Two abandoned eruptive oil and gas wells were selected, with a depth range of 1950-1960m. After the waterproof layer and sealing layer were applied inside, they had gas and liquid sealing conditions to form an underground high-pressure storage tank body.

[0100] (2) A Φ273 mm liquid inlet airtight casing (forming the fluid injection channel 21) and a Φ197.5 mm liquid outlet airtight casing (forming the fluid discharge channel 22) are inserted into the oil and gas well between the ground and the underground high-pressure storage tank body, and the depth of the casing mouth is 1950 m.

[0101] (3) Through on-site geostress analysis and testing, it was determined that the rupture stress of the underground high-pressure storage tank was 39.8 MPa, and the upper limit internal pressure after the flow battery electrolyte was injected into the tank was set at 30 MPa.

[0102] (4) Use the abandoned photovoltaic power that is difficult to connect to the power grid to start the gas compressor, pressurize the high-pressure nitrogen into the underground high-pressure storage tank through the liquid-tight casing, strictly control the internal pressure to close to 18MPa by the gas injection volume, and stop the gas injection.

[0103] (5) Use the abandoned wind power that is difficult to integrate into the power grid to start the liquid pump and transport the flow battery electrolyte to the underground high-pressure storage tank through the liquid inlet airtight casing. As the flow battery electrolyte is injected, the internal pressure of the underground high-pressure storage tank rises and the nitrogen in the high-pressure storage tank is compressed. When the internal pressure of the high-pressure storage tank is about to reach 30MPa, open the liquid outlet airtight casing. Due to the high pressure of the abandoned oil and gas wells, the flow battery electrolyte is squeezed into the liquid outlet airtight casing by the internal air pressure and gradually flows upward into the flow battery circulation pipeline.

[0104] (6) A set of water turbine systems (water turbine generators 3) are provided between the surface outlet pipes and the circulation pipelines of the multiple flow battery systems. While the electrolyte is diverted into each flow battery system, the water turbine generators 3 are driven to generate electricity to complete the mechanical energy storage process. The flow rate of the electrolyte at the outlet pipe is adjusted by the water turbine generator 3, and the flow rate at the inlet is adjusted in coordination with the liquid pump at the inlet. The total volume of the liquid in the underground high-pressure storage tank is adjusted to be stable within a certain range, and the internal pressure of the tank is maintained at 22MPa. The underground high-pressure storage tank system forms a dynamic balance.

[0105] (7) Start multiple liquid flow battery systems to perform normal charge and discharge cycles. At the same time, the electrolyte will flow into the liquid flow battery after passing through the hydro-generator 3 to maintain the stable operation of the liquid flow battery and complete the electrochemical energy storage process. The electrolyte flowing through the liquid flow battery 4 is once again pressed into the abandoned oil and gas well 1 through the buffer tank 7 to repeat the above process for circulation, and according to the actual photovoltaic power generation, the flow of the electrolyte in the pipeline is accelerated or slowed down, and the operation of the liquid flow battery is adjusted by feedback regulation.

[0106] Example 4: Figure 4 As shown, the abandoned oil and gas well 1 does not need to be pressurized by injecting gas, and the positive and negative electrodes of the two flow batteries 4 correspond to the two abandoned oil and gas wells 1, that is, no gas is required, and the wells can be self-sprayed, which is a many-to-many situation:

[0107] (1) Select a number of abandoned oil and gas wells that cannot flow by themselves, with a depth range of 1600-1700m. After applying a waterproof layer and a sealing layer inside, they have gas and liquid sealing conditions to form two groups of underground high-pressure storage tanks, one group as a positive electrode electrolyte storage tank, and the other group as a negative electrode electrolyte storage tank. Each group contains an equal or unequal amount of abandoned oil and gas wells that cannot flow by themselves, and the electrolytes in each group are respectively collected into the main inlet pipeline and the main outlet pipeline through the underground pipeline network.

[0108] (2) A total liquid inlet gas-tight casing and a total liquid outlet gas-tight casing are lowered into the oil and gas well between the ground and the underground high-pressure storage tank body, and the depth of the casing mouth is 1650m. The total liquid inlet pipeline is divided through the underground pipeline network and connected to the corresponding electrolyte storage tanks of each group; each electrolyte storage tank is merged through the underground pipeline network, and the liquid outlet pipelines are gathered into the total liquid outlet pipeline.

[0109] (3) Through on-site geostress analysis and testing, it was determined that the rupture stress of the underground high-pressure storage tank is 30.2 MPa.

[0110] (4) Use the abandoned photovoltaic power that is difficult to integrate into the power grid to start the liquid pump, and transport the electrolyte of the liquid flow battery through the main liquid inlet airtight casing and the underground pipeline network to the corresponding underground high-pressure storage tanks. As the liquid flow battery electrolyte is injected, the internal pressure of the underground high-pressure storage tank rises. Open the liquid outlet airtight casing. Due to the high pressure of the abandoned oil and gas wells, the liquid flow battery electrolyte is squeezed into the liquid outlet airtight casing by the internal air pressure, and gradually flows upward into the liquid flow battery circulation pipeline.

[0111] (5) A turbine system (hydraulic generator 3) is provided between the main liquid outlet on the ground and the circulation pipeline of a single flow battery system to drive the turbine system to generate electricity and complete the mechanical energy storage process. The flow rate of the electrolyte at the outlet casing is adjusted by the hydraulic generator 3, and the flow rate at the inlet is adjusted in coordination with the liquid pump at the inlet, so that the underground high-pressure storage tank system forms a dynamic balance.

[0112] (6) Start multiple liquid flow battery systems to perform normal charge and discharge cycles. At the same time, the electrolyte will flow into the liquid flow battery after passing through the hydro-generator 3 to maintain the stable operation of the liquid flow battery and complete the electrochemical energy storage process. The electrolyte flowing through the liquid flow battery 4 is once again pressed into the abandoned oil and gas well 1 through the buffer tank 7 to repeat the above process for circulation, and according to the actual photovoltaic power generation, the flow of the electrolyte in the pipeline is accelerated or slowed down, and the operation of the liquid flow battery is adjusted by feedback regulation.

[0113] The above description is only an illustrative embodiment of the present invention and is not intended to limit the scope of the present invention. Any equivalent changes and modifications made by any person skilled in the art without departing from the concept and principle of the present invention shall fall within the scope of protection of the present invention.

Claims

1. A hybrid energy storage method based on compressed fluid and chemical energy storage of abandoned oil and gas wells, characterized in that: The following steps are involved: Step S1, selecting at least one abandoned oil and gas well; Step S2, establishing a connection channel between the ground and the abandoned oil and gas well, including a fluid injection channel and a fluid discharge channel; the bottom end of the fluid injection channel is located in the sealed and waterproof abandoned oil and gas well, and the bottom end of the fluid discharge channel is set lower than the bottom end of the fluid injection channel; the top outlet of the fluid discharge channel is connected to the hydro-generator and the flow battery; Step S3, using the wind and solar power waste electricity to inject a set volume of electrolyte of the flow battery into the abandoned oil and gas well through the fluid injection channel; converting the abandoned wind and solar power into mechanical energy to complete the compressed fluid energy storage; Step S4, the high pressure in the abandoned oil and gas well discharges the electrolyte into the hydro-generator through the fluid discharge channel, and the hydro-generator generates electricity under the action of the electrolyte, converting mechanical energy into electrical energy; Step S5, the hydro-generator delivers the electrolyte to the flow battery at a set flow rate to maintain the operation of the flow battery and perform electrochemical energy storage; Step S6: The electrolyte flowing out of the flow battery can be circulated into the abandoned oil and gas well, and steps S3-S5 are repeated to complete the mixed energy storage of compressed fluid and chemical energy storage based on the abandoned oil and gas well.

2. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 1 is characterized in that: In step S6, the outlet of the liquid flow battery is connected to the inlet of the buffer tank, and the outlet of the buffer tank can be connected to the fluid injection channel; the electrolyte flowing through the liquid flow battery is once again pressed into the abandoned oil and gas well through the buffer tank.

3. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 2 is characterized in that: In step S6, the outlet of the liquid flow battery or the outlet of the buffer tank is connected to a liquid storage tank; when the wind and solar power waste electricity is insufficient, the electrolyte flowing through the liquid flow battery flows into the liquid storage tank for storage.

4. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 1 is characterized in that: In step S3, an electric liquid injection device is arranged at the top of the fluid injection channel, and the electric liquid injection device is supplied with electric energy by wind and solar waste electricity.

5. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 1 is characterized in that: In step S5, a pressure sensor is provided at the electrolyte outlet of the hydro-turbine generator, and the pressure sensor senses the flow pressure value of the electrolyte and reacts to the hydro-turbine generator to adjust the power of the hydro-turbine generator so that the electrolyte flows into the flow battery at a set flow rate.

6. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 1, characterized in that: In step S2, a sealed and waterproof underground high-pressure storage space is provided in the abandoned oil and gas well, and the bottom ends of the fluid injection channel and the fluid discharge channel are located in the underground high-pressure storage space; the underground high-pressure storage space is a single independent space body or a group of interconnected space bodies; the depth range of the underground high-pressure storage space is 0 to 20,000 m below the ground.

7. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 6 is characterized in that: The distance between the bottom ends of the fluid injection channel and the fluid discharge channel and the bottom surface of the underground high-pressure storage space is 1 to 50 m.

8. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 6 is characterized in that: In step S2, when the air pressure in the underground high-pressure storage space is greater than or equal to the set pressure, a waterproof layer is applied in the underground high-pressure storage space.

9. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 6, characterized in that: In step S2, when the air pressure in the underground high-pressure storage space is lower than the set pressure, a waterproof layer and a sealing layer are applied to the underground high-pressure storage space, and gas is pumped into the abandoned oil and gas well to increase the air pressure in the underground high-pressure storage space.

10. The hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as claimed in claim 1, characterized in that: In step S2, one of the abandoned oil and gas wells is connected to one of the flow batteries, or one of the abandoned oil and gas wells is connected to multiple of the flow batteries, or one of the flow batteries is connected to multiple of the abandoned oil and gas wells.

11. A hybrid energy storage system based on compressed fluid and chemical energy storage of abandoned oil and gas wells, characterized in that: Used in the hybrid energy storage method based on abandoned oil and gas well compressed fluid and chemical energy storage as described in any one of claims 1 to 10; The hybrid energy storage system based on abandoned oil and gas well compressed fluid and chemical energy storage includes: At least one abandoned oil and gas well; At least 1 hydroelectric generator; At least one surface-mounted flow battery; At least one group of connecting channels, one group of connecting channels includes at least one fluid injection channel and at least one fluid discharge channel; the bottom end of the fluid injection channel is located in the abandoned oil and gas well, the bottom end of the fluid discharge channel is located in the abandoned oil and gas well, and the bottom end of the fluid discharge channel is arranged lower than the bottom end of the fluid injection channel; the top outlet of the fluid discharge channel is sequentially connected to the hydro-generator and the flow battery; the outlet of the flow battery can be connected to the top of the fluid injection channel; the top of the fluid injection channel is connected to an electric injection device supplied with electric energy by wind and solar waste electricity.

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