Energy storage system of porous reservoir

Abstract

The invention relates to the technical field of energy storage, in particular to a porous reservoir energy storage system which comprises a plurality of injection and production well pipes, a plurality of directional wells, an air compression module, a separation module, an air expansion module and a heat storage module. The multiple injection and production well pipes are arranged at intervals at preset distances; the multiple directional wells communicate with the first end of the injection and production well pipe. The air compression module is communicated with the injection and production well pipe through an air inlet pipeline; the air expansion module is communicated with the separation module through an air outlet pipeline; the heat storage module is used for collecting and storing heat of compressed air and releasing heat to the air expansion module. According to the energy storage system of the porous reservoir, the injection-production flow is dispersed, the injection-production flow speed is reduced, the flow resistance is reduced, and scouring to a geologic structure is effectively weakened; and sand particles and / or liquid in the compressed air are separated through the separation module, so that the purity of the compressed air is improved. The energy storage system of the porous reservoir has the advantages of being high in efficiency, good in safety and more environmentally friendly.

Description

Technical Field

[0001] This invention relates to the field of energy storage technology, and in particular to an energy storage system with porous reservoirs. Background Technology

[0002] Energy storage is an important technical means to solve the imbalance between energy supply and demand. For example, due to the day and night work and rest patterns of the whole society, the power load often drops at night and peaks during the day. Or, due to the influence of electric heating in winter and electric cooling in summer, the total electricity consumption of the whole society in summer and winter is much higher than that in spring and autumn.

[0003] To address the aforementioned imbalance between power supply and demand, energy storage can be developed. Common large-capacity, long-duration energy storage technologies include pumped hydro storage and compressed air energy storage (CASS). CASS converts electrical energy into the pressure potential energy of high-pressure air through air compression. The expansion of this high-pressure air then drives a gas expander, which in turn powers a generator. Therefore, the construction and operation of a CASS system requires a gas storage facility to store compressed air. The size of the gas storage facility directly determines the system's power storage capacity—the larger the facility, the more compressed air it can store, the more electrical energy is consumed in producing compressed air, and the more electrical energy can be output during compressed air expansion. In other words, the CASS system has a stronger capacity to absorb electrical energy during storage and a greater capacity to output electrical energy during power generation. As a large-capacity, long-duration energy storage technology, compressed air energy storage typically has a power generation capacity of 100MW to 300MW and a power generation duration of 4h to 10h. The corresponding required gas storage volume is generally hundreds of thousands to millions of cubic meters. However, using artificial pressure vessels for such large storage facilities is too costly. Therefore, salt caverns—large underground mine shafts left after the mining of salt rock—are currently the primary method for gas storage. Depleted oil and gas reservoirs, which are oil and gas fields that have ceased production after long-term exploitation, have been successfully used for large-scale underground natural gas storage. This involves injecting surplus natural gas into depleted oil and gas reservoirs and releasing it to meet market demand when natural gas is scarce.

[0004] Referring to natural gas storage, depleted oil and gas reservoirs also have technical feasibility for compressed air energy storage. However, it is still necessary to solve the problems of low system efficiency, poor safety, and environmental unfriendliness when using porous media geological formations for compressed air energy storage. Summary of the Invention

[0005] This invention provides an energy storage device and power generation system for porous reservoirs, which solves the defects of low system efficiency, poor safety and environmental unfriendliness in the application of porous media geological formations to compressed air energy storage in the prior art.

[0006] This invention provides an energy storage system for porous reservoirs, comprising: Multiple injection and production well pipes are installed at preset intervals; Multiple directional wells extend into the interior of a porous underground reservoir and are connected to the first end of the injection-production well pipe; An air compression module is connected to the second end of the injection-production well pipe via an air intake pipe; The separation module is connected to the third end of the injection-production well pipe via an air outlet pipe and is used to separate sand particles and / or liquids in compressed air. An air expansion module is connected to the separation module via an air outlet pipe; A heat storage module is thermally coupled to the air compression module for collecting and storing heat from the compressed air; the heat storage module is also thermally coupled to the air expansion module for releasing heat to the air expansion module.

[0007] According to the energy storage system for porous reservoirs provided by the present invention, the air compression module includes: Air compressor; The first heat exchanger has a first heat exchange pipeline and a second heat exchange pipeline that are thermally coupled. The first heat exchange pipeline is connected to the output end of the air compressor, and the second heat exchange pipeline is connected to the heat storage module.

[0008] According to the porous reservoir energy storage system provided by the present invention, multiple air compressors and first heat exchangers are provided, and at least one first heat exchanger is provided between two adjacent air compressors, and at least one air compressor is provided between two adjacent first heat exchangers.

[0009] According to the energy storage system for porous reservoirs provided by the present invention, the air expansion module includes: Air expander; The second heat exchanger has a thermally coupled third heat exchange pipeline and a fourth heat exchange pipeline. The third heat exchange pipeline is connected to the input end of the air expander, and the fourth heat exchange pipeline is connected to the heat storage module.

[0010] According to the porous reservoir energy storage system provided by the present invention, multiple air expanders and second heat exchangers are provided, and at least one second heat exchanger is provided between two adjacent air expanders, and at least one air expander is provided between two adjacent second heat exchangers.

[0011] According to the energy storage system for porous reservoirs provided by the present invention, the separation module includes: The buffer desander is connected to the third end of the injection-production well pipe through the air outlet pipe and is used to remove sand particles entrained in the compressed air. The gas-liquid separator is connected between the buffer desander and the air expansion module via the air outlet pipe, and is used to remove liquid entrained in the compressed air.

[0012] According to the energy storage system of the porous reservoir provided by the present invention, the bottom of the buffer desander is the air inlet and the top is the exhaust outlet; The bottom of the buffer desander is filled with a liquid working medium that has an adhesive effect on sand particles; A baffle structure is provided on the top of the buffer desander to block the entrained liquid working medium and sand particles.

[0013] According to the energy storage system for porous reservoirs provided by the present invention, the directional well penetrates the underground porous reservoir laterally at a horizontal or set angle for a set length, and the horizontal well pipe is densely covered with holes for gas flow.

[0014] The energy storage system for porous reservoirs provided by the present invention further includes: A gas detection device is installed at the exhaust end of the air expansion module to detect the content of combustible pollutants in the exhaust gas. The exhaust gas treatment device is connected to the exhaust end of the air expansion module and is used to treat combustible pollutants in the exhaust gas.

[0015] The energy storage system for porous reservoirs provided by the present invention further includes: The first valve body is located at the exhaust end of the intake pipe; The second valve body is located at the air inlet end of the air outlet pipe.

[0016] This invention provides an energy storage system for porous reservoirs, comprising: multiple injection-production well pipes, multiple directional wells, an air compression module, a separation module, an air expansion module, and a heat storage module. The multiple injection-production well pipes are arranged at preset intervals; the multiple directional wells extend into the interior of the underground porous reservoir and are connected to the first end of the injection-production well pipes; the air compression module is connected to the second end of the injection-production well pipes via an air inlet pipe; the separation module is connected to the third end of the injection-production well pipes via an air outlet pipe, for separating sand particles and / or liquids from the compressed air; the air expansion module is connected to the separation module via an air outlet pipe; the heat storage module is thermally coupled to the air compression module for collecting and storing the heat from the compressed air; the heat storage module is thermally coupled to the air expansion module for releasing heat to the air expansion module. This invention provides an energy storage system for porous reservoirs. By setting up multiple injection and production wells and directional wells, it effectively weakens the scouring of the porous geological structure by the injection and production gas flow while dispersing the injection and production flow rate, reducing the injection and production flow velocity, and decreasing flow resistance. This reduces the shedding of sand particles and weakens the ability of the gas flow to entrain sand particles, thus reducing the amount of sand particles entrained in the gas flow produced from each injection and production well to the surface, lowering the safety risks of subsequent equipment operation. Furthermore, by incorporating a separation module, sand particles and / or liquids are separated from the compressed air, thereby improving the sand removal rate and / or entrained liquid removal rate, and ultimately increasing the purity of the compressed air. Therefore, the energy storage system for porous reservoirs provided by this invention has the advantages of high efficiency, good safety, and greater environmental friendliness. Attached Figure Description

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

[0018] Figure 1 This is a schematic diagram of the structure of a porous reservoir energy storage system provided in one embodiment of the present invention.

[0019] Figure label: 1: Air compressor; 2: First heat exchanger; 3: Heat storage module; 4: Injection-production well casing; 5: Directional well; 6: Depleted oil and gas reservoir type geological reservoir; 7: Buffer desander; 8: Gas-liquid separator; 9: Second heat exchanger; 10: Air expander; 11: Electric motor; 12: Generator; 13: First valve body; 14: Second valve body. Detailed Implementation

[0020] To make the objectives, technical solutions, and advantages of this invention clearer, the technical solutions of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this invention. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0021] In the description of this embodiment, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this embodiment and simplifying the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this embodiment.

[0022] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this embodiment, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0023] In this embodiment, unless otherwise explicitly specified and limited, the terms "set," "install," "connect," "link," and "fix" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise explicitly limited. Those skilled in the art can understand the specific meaning of the above terms in this embodiment based on the specific circumstances.

[0024] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first feature is in direct contact with the second feature, or that the first feature is in indirect contact with the second feature through an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0025] Referring to natural gas storage, depleted oil and gas reservoirs also have technical feasibility for application in compressed air energy storage. However, the following problems still need to be addressed when using porous media geological formations for compressed air energy storage: 1. First, oil and gas reservoirs are generally porous geological formations, which differ from the large cavity gas storage conditions of mine caverns and salt caverns. They have the significant characteristic of high flow resistance, making gas injection and release difficult.

[0026] 2. Secondly, due to the large flow rate and velocity of compressed air energy storage system during injection and extraction, the reciprocating flow through the porous media reservoir structure may carry sand particles into the gas flow for extraction, posing a potential threat to the operation of subsequent equipment.

[0027] 3. In addition, the depletion of oil and gas reservoirs does not mean that there is no oil and gas left in the underground reservoir space. Therefore, when the gas is extracted, it may contain combustible gas components such as methane. When the concentration reaches the explosion limit, there may be a risk of combustion and explosion. Direct emission will pollute the environment and is also a waste of energy.

[0028] To address the shortcomings of existing technologies that utilize porous media geological formations for compressed air energy storage, such as low system efficiency, poor safety, and environmental unfriendliness, this invention proposes an energy storage system using porous reservoirs.

[0029] The following is combined with Figure 1 This invention describes an energy storage system for a porous reservoir. The energy storage system for the porous reservoir includes: multiple injection and production well pipes 4, multiple directional wells 5, an air compression module, a separation module, an air expansion module, and a thermal storage module 3.

[0030] The system includes multiple injection-production well pipes 4 spaced at preset intervals; multiple directional wells 5 extending into the interior of the underground porous reservoir and connected to the first end of the injection-production well pipes 4; an air compression module connected to the second end of the injection-production well pipes 4 via an air inlet pipe; a separation module connected to the third end of the injection-production well pipes 4 via an air outlet pipe, used to separate sand particles and / or liquids from the compressed air; an air expansion module connected to the separation module via an air outlet pipe; a heat storage module 3 thermally coupled to the air compression module, used to collect and store the heat of the compressed air; and a heat storage module 3 thermally coupled to the air expansion module, used to release heat to the air expansion module.

[0031] The underground porous reservoir can be a depleted oil and gas reservoir type geological reservoir 6, or it can be changed to a porous medium geological reservoir such as an underground aquifer or sandstone layer. In the following embodiments, the porous reservoir is described using the depleted oil and gas reservoir type geological reservoir 6 as an example. The air compression module, separation module, air expansion module and heat storage module 3 are all set on the ground, the injection and production well pipe 4 extends underground, and the directional well 5 is set inside the depleted oil and gas reservoir type geological reservoir 6.

[0032] Specifically, due to the significant characteristic of porous media geology with high flow resistance, gas injection and release are difficult. In this invention, the bottoms of each injection-production well pipe 4 are distributed at a certain distance in the depleted oil and gas reservoir 6. The purpose of this arrangement is to ensure that each reservoir space in the depleted oil and gas reservoir 6 can be connected to an injection-production well pipe 4 within a short distance, thereby reducing the flow distance required for gas transmission and reducing the flow resistance during gas injection and production. At the same time, setting multiple injection-production well pipes 4 can also distribute the injection and production air flow to multiple flow paths, thereby reducing the injection and production flow rate and velocity of each flow path, further reducing the flow resistance during gas injection and production.

[0033] Furthermore, multiple injection and production well pipes 4 are connected one-to-one with multiple directional wells 5, and are connected to the main pipeline in parallel. The bottom of the injection and production well pipes 4 are inserted into the depleted oil and gas reservoir type geological reservoir 6 at predetermined intervals, and the tops can be spaced out or clustered together, but all converge to the same main pipe.

[0034] The air compression module is used to compress air and store energy through compressed air. On one hand, the air compression module is connected to the injection-production well pipe 4 through the air intake pipeline, and inputs compressed air into the depleted oil and gas reservoir type geological reservoir 6 for storage; on the other hand, the heat storage module 3 is thermally coupled to the air compression module to collect and store the heat of the compressed air.

[0035] The air expansion module is used to expand compressed air, and output energy by doing work through the expansion of compressed air. On the one hand, the injection-production well pipe 4 is connected to the separation module and the air expansion module in sequence through the air outlet pipeline, so as to output and expand the compressed air stored in the depleted oil and gas reservoir 6, thereby realizing energy output; on the other hand, the heat storage module 3 is thermally coupled to the air expansion module, and is used to release heat to the air expansion module, thereby realizing energy output.

[0036] The separation module is located between the third end of the injection-production well pipe 4 and the air expansion module. It is mainly used to separate sand particles and / or liquids from the compressed air output from the depleted oil and gas reservoir type geological reservoir 6, thereby improving the sand removal rate and / or entrained liquid removal rate, so as to improve the purity of the compressed air.

[0037] The heat storage module 3 is connected to the exhaust end of the air compression module. It is mainly used to cool the compressed exhaust, collect and store the heat of compression, and transfer the heat to the air expansion module when it needs to be released.

[0038] The porous reservoir energy storage system of the present invention also includes an electric motor 11 and a generator 12. Each air compression module can be driven by the same electric motor 11, and each air expansion module can jointly drive the same generator 12. In other embodiments, multiple electric motors 11 and / or multiple generators 12 may also be provided.

[0039] The working process of this invention is as follows: During energy storage, the electric motor 11 consumes electrical energy to drive the air compression module to gradually pressurize the ambient air and then transport it through each injection and production well pipe 4 into the depleted oil and gas reservoir type geological reservoir 6 for storage. At the same time, the heat energy in the exhaust of each air compression module is transferred to the heat storage module 3 for storage through heat exchange.

[0040] During power generation, the depleted oil and gas reservoir 6 releases the stored compressed air, which is first transported to the separation module through each injection and production well pipe 4 to remove entrained sand particles and / or entrained liquids. Then, it enters the air expansion module to expand and do work, driving the generator 12 to output electrical energy. In the above process, the heat energy stored in the heat storage module 3 is used to heat the air intake of each air expansion module through heat exchange, thereby improving the gas's ability to do work.

[0041] This invention provides an energy storage system for a porous reservoir, comprising: multiple injection-production well pipes 4, multiple directional wells 5, an air compression module, a separation module, an air expansion module, and a heat storage module 3. The multiple injection-production well pipes 4 are arranged at preset intervals; the multiple directional wells 5 extend into the interior of the underground porous reservoir and are connected to the first end of the injection-production well pipes 4; the air compression module is connected to the second end of the injection-production well pipes 4 via an air inlet pipe; the separation module is connected to the third end of the injection-production well pipes 4 via an air outlet pipe, for separating sand particles and / or liquids from the compressed air; the air expansion module is connected to the separation module via an air outlet pipe; the heat storage module 3 is thermally coupled to the air compression module, for collecting and storing the heat of the compressed air; the heat storage module 3 is also thermally coupled to the air expansion module, for releasing heat to the air expansion module. This invention provides an energy storage system for porous reservoirs. By setting up multiple injection and production wells 4 and directional wells 5, it effectively weakens the scouring of the porous geological structure by the injection and production gas flow while dispersing the injection and production flow rate, reducing the injection and production flow velocity, and decreasing flow resistance. This reduces the shedding of sand particles and weakens the ability of the gas flow to entrain sand particles, thus reducing the amount of sand particles entrained in the gas flow produced from each injection and production well 4 to the surface, lowering the safety risks of subsequent equipment operation. By setting up a separation module, sand particles and / or liquids are separated from the compressed air, thereby improving the sand removal rate and / or entrained liquid removal rate, and improving the purity of the compressed air. Therefore, the energy storage system for porous reservoirs provided by this invention has the advantages of high efficiency, good safety, and greater environmental friendliness.

[0042] In one embodiment of the present invention, the air compression module includes an air compressor 1 and a first heat exchanger 2. The first heat exchanger 2 has a thermally coupled first heat exchange pipe and a second heat exchange pipe. The first heat exchange pipe is connected to the output end of the air compressor 1, and the second heat exchange pipe is connected to a heat storage module 3. In this embodiment, by setting the first heat exchanger 2 at the exhaust end of the air compressor, heat in the exhaust of the air compressor 1 is absorbed and stored in the heat storage module 3.

[0043] In one embodiment of the present invention, multiple air compressors 1 and first heat exchangers 2 are provided, and at least one first heat exchanger 2 is provided between two adjacent air compressors 1, and at least one air compressor 1 is provided between two adjacent first heat exchangers 2. In this embodiment, multiple air compressors 1 and first heat exchangers 2 are provided, and multiple air compressors 1 can be provided in parallel and / or in series. Preferably, a first heat exchanger 2 is provided between two air compressors 1, and an air compressor 1 is provided between two first heat exchangers 2, thus forming a configuration as shown in the figure. Figure 1 The air compressor 1 and the first heat exchanger 2 are connected in series, thus realizing a multi-stage compression and multi-stage heat exchange structure and improving energy storage efficiency.

[0044] In one embodiment of the present invention, the air expansion module includes an air expander 10 and a second heat exchanger 9. The second heat exchanger 9 has a thermally coupled third heat exchange pipe and a fourth heat exchange pipe. The third heat exchange pipe is connected to the input end of the air expander 10, and the fourth heat exchange pipe is connected to the heat storage module 3. In this embodiment, by providing the second heat exchanger 9 at the air inlet end of the air expander 10, stored thermal energy is obtained from the heat storage module 3 and used to heat the exhaust gas of the gas-liquid separator 8.

[0045] In one embodiment of the present invention, multiple air expanders 10 and second heat exchangers 9 are provided, and at least one second heat exchanger 9 is provided between two adjacent air expanders 10, and at least one air expander 10 is provided between two adjacent second heat exchangers 9. In this embodiment, multiple air expanders 10 and second heat exchangers 9 are provided, and multiple air expanders 10 can be provided in parallel and / or in series. Preferably, one second heat exchanger 9 is provided between two air expanders 10, and one air expander 10 is provided between two second heat exchangers 9, thus forming a configuration as shown in the figure. Figure 1 The air expander 10 and the second heat exchanger 9 are connected in series, thus realizing a multi-stage expansion and multi-stage heat exchange structure, improving energy utilization efficiency.

[0046] In one embodiment of the present invention, the separation module includes a buffer desander 7 and a gas-liquid separator 8. The buffer desander 7 is connected to the third end of the injection-production well pipe 4 via an air outlet pipeline and is used to remove sand particles entrained in the compressed air. The gas-liquid separator 8 is connected between the buffer desander 7 and the air expansion module via an air outlet pipeline and is used to remove liquid entrained in the compressed air. In this embodiment, by sequentially connecting the buffer desander 7 and the gas-liquid separator 8 to the third end of the injection-production well pipe 4, the buffer desander 7 is used to remove sand particles carried in the gas produced from the underground depleted oil and gas reservoir type geological reservoir 6, and the gas-liquid separator 8 is used to further remove liquid particles carried in the exhaust gas of the buffer desander 7, thereby improving the purity of the compressed air.

[0047] In one embodiment of the present invention, the bottom of the buffer sand separator 7 is the air inlet and the top is the exhaust outlet; the bottom of the buffer sand separator 7 is filled with a liquid working medium that has an adhesive effect on sand particles; a baffle structure is provided at the top of the buffer sand separator 7 to block the entrained liquid working medium and sand particles. Preferably, the liquid working medium that has an adhesive effect on sand particles can be water.

[0048] In the above embodiment, the buffer desander 7 has a large capacity, and the interface diameter with the injection / production well pipe 4 is larger than that of the main pipe, in order to reduce the flow velocity of the gas entering the buffer desander 7. Secondly, the lower part of the buffer desander 7 is filled with water to a certain depth. The exhaust gas from the main pipe enters from the bottom of the buffer desander 7, passes through the filled water, and enters the upper part. During this process, since the exhaust gas entering the buffer desander 7 has already slowed down at the inlet, most of the sand particles entrained by the exhaust gas remain in the water due to gravity and the viscosity of the water, and the ability of the gas flow to entrain water particles again is also weakened. In order to further remove the water entrained in the gas flow after passing through the filled water and the small amount of sand particles that may still be entrained, referring to the baffle impact gas-liquid separator 8, a baffle structure is provided in the upper part of the buffer desander 7. When the gas flow impacts the baffle, the entrained droplets and sand particles collide with the baffle and gather into large particles, which are then separated from the gas flow and fall off under the action of gravity.

[0049] In other embodiments, an airflow distributor is provided at the bottom of the buffer sand separator 7 so that the exhaust gas from the main pipe can flow more evenly through the filling water, thereby improving the sand removal capacity; a spiral flow channel can also be provided on the upper part of the buffer sand separator 7, similar to the velocity-type gas-liquid separator 8, to remove sand and liquid; multiple buffer sand separators 7 can also be connected in series or in parallel to further reduce the gas flow rate in each buffer sand separator 7 and increase the flow of air through the filling water, thereby improving the sand removal capacity.

[0050] After the exhaust gas from the main pipe flows through the buffer sand remover 7, it enters the gas-liquid separator 8. The gas-liquid separator 8 can be an impact type or a velocity type. Its main purpose is to remove liquid droplets entrained in the exhaust gas, and it can also further remove residual sand particles.

[0051] In one embodiment of the present invention, the directional well 5 penetrates the underground porous reservoir horizontally or at a set angle for a set length, and the horizontal well pipe is densely covered with holes for gas flow. Specifically, the directional well 5 can be a horizontal well, and its wall surface has dense holes opened by pre-set or downhole perforation technology, thereby further expanding the total connection area between each injection-production well pipe 4 and the surrounding reservoir space in the horizontal direction or a certain direction, which can further reduce the injection-production flow rate and velocity per unit connection area, and further reduce the flow resistance of gas injection and production. The location of each injection-production well pipe 4 on the ground is not specifically required, but for the convenience of surface well site management, some injection-production well pipes 4 can be located at the same location, or all of them can be located at the same location, but the above-ground parts of each injection-production well pipe 4 will eventually converge on the main pipe connecting the air compression module and the air expansion module.

[0052] In one embodiment of the present invention, the energy storage system of the porous reservoir further includes a gas detection device and an exhaust gas treatment device. The gas detection device is located at the exhaust end of the air expansion module and is used to detect the content of combustible pollutants in the exhaust gas; the exhaust gas treatment device is connected to the exhaust end of the air expansion module and is used to treat the combustible pollutants in the exhaust gas. Preferably, the exhaust gas treatment device can be a combustion device, which can burn the exhaust gas and store the heat energy in the heat storage module 3.

[0053] In the above embodiment, after the gas passes through the gas-liquid separator 8, it is depressurized and discharged as exhaust gas after being depressurized by the air expansion module. To prevent combustible pollutants such as methane carried in the exhaust gas from being released into the atmosphere, the concentration of combustible pollutants in the exhaust gas is detected by a gas detection device. If the concentration exceeds the standard, the system introduces the exhaust gas into the heat storage module 3 for combustion to heat the heat transfer medium therein, thereby converting the chemical energy of combustibles such as methane into thermal energy for storage. The exhaust gas after combustion can be further treated by conventional flue gas desulfurization, decarbonization and other environmental protection methods before being discharged, or it can be treated by carbon dioxide adsorption and recovery methods before being discharged. If the concentration of combustible pollutants such as methane carried in the exhaust gas is lower than the national standards, it can also be directly discharged into the atmosphere. It should be noted that in order to prevent the mixed gas containing combustible components such as methane from igniting and exploding when heated during the power generation process, it is necessary to analyze the content and ignition point of combustible components to determine the lowest ignition point of the component most likely to reach the explosion limit, and then control the temperature of the high-temperature heat transfer medium in the heat storage module 3 below the ignition point temperature.

[0054] In one embodiment of the present invention, the energy storage system of the porous reservoir further includes a first valve body 13 and a second valve body 14. The first valve body 13 is disposed at the exhaust end of the intake pipe; the second valve body 14 is disposed at the intake end of the exhaust pipe. The intake / exhaust of the depleted oil and gas reservoir type geological reservoir 6 is controlled by the first valve body 13 and the second valve body 14.

[0055] In summary, the porous reservoir energy storage system provided by this invention has the following beneficial effects: 1. By setting multiple injection and production well pipes 4 at intervals, it is possible to achieve simultaneous gas injection and production at multiple points in the underground depleted oil and gas reservoir type geological reservoir 6, thereby reducing the gas flow rate and velocity at each point, improving the gas flow capacity of the porous medium space, thus alleviating the problem of high flow resistance. At the same time, the reduced flow velocity also helps to weaken the scouring of the geological structure by the gas flow and reduce sand inclusions in the gas production. 2. By setting up a horizontal well with perforated wall at the bottom of the injection and production well pipe 4, the flow area between each injection and production well pipe 4 and the porous medium space can be further increased, thereby further improving the gas flow capacity of the porous medium space and reducing sand inclusions in the gas production. 3. By setting up a buffer desander 7, most of the sand particles entrained in the produced gas can be effectively removed, and the sand removal rate can be further improved by setting up multiple buffer desanders 7 in series and parallel; by setting up a gas-liquid separator 8, most of the liquid that may be entrained in the buffer desander 7 can be removed from the gas flow. 4. By controlling the high-temperature side temperature of the second heat exchanger 9, the maximum temperature of the extracted gas can be controlled below the ignition point of the residual oil and gas components, thereby preventing the oil and gas mixture from igniting and exploding; by burning the exhaust gas of the air expander 10 module containing a high concentration of residual oil and gas and using it to heat the heat storage medium in the heat storage module 3, the residual oil and gas can be prevented from leaking into the environment and causing pollution, while effectively using the energy contained therein for the operation and power generation of the compressed air energy storage system.

[0056] The device embodiments described above are merely illustrative. The units described as separate components may or may not be physically separate, and the components shown as units may or may not be physical units; that is, they may be located in one place or distributed across multiple units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs. Those skilled in the art can understand and implement this without any creative effort.

[0057] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. An energy storage system with porous reservoirs, characterized in that, include: Multiple injection and production well pipes (4) are set at preset distance intervals; Multiple directional wells (5) extend into the interior of the underground porous reservoir and are connected to the first end of the injection-production well pipe (4); An air compression module is connected to the second end of the injection-production well pipe (4) via an air intake pipe; The separation module is connected to the third end of the injection-production well pipe (4) via an air outlet pipe and is used to separate sand particles and / or liquid in compressed air; An air expansion module is connected to the separation module via an air outlet pipe; The heat storage module (3) is thermally coupled to the air compression module and is used to collect and store the heat of compressed air; the heat storage module (3) is thermally coupled to the air expansion module and is used to release heat to the air expansion module.

2. The energy storage system for porous reservoirs according to claim 1, characterized in that, The air compression module includes: Air compressor (1); The first heat exchanger (2) has a first heat exchange pipeline and a second heat exchange pipeline that are thermally coupled. The first heat exchange pipeline is connected to the output end of the air compressor (1), and the second heat exchange pipeline is connected to the heat storage module (3).

3. The energy storage system with porous reservoirs according to claim 2, characterized in that, Multiple air compressors (1) and multiple first heat exchangers (2) are provided, and at least one first heat exchanger (2) is provided between two adjacent air compressors (1) and at least one air compressor (1) is provided between two adjacent first heat exchangers (2).

4. The energy storage system for porous reservoirs according to claim 1, characterized in that, The air expansion module includes: Air expander (10); The second heat exchanger (9) has a thermally coupled third heat exchange pipeline and a fourth heat exchange pipeline. The third heat exchange pipeline is connected to the input end of the air expander (10), and the fourth heat exchange pipeline is connected to the heat storage module (3).

5. The energy storage system for porous reservoirs according to claim 4, characterized in that, Multiple air expanders (10) and second heat exchangers (9) are provided, and at least one second heat exchanger (9) is provided between two adjacent air expanders (10), and at least one air expander (10) is provided between two adjacent second heat exchangers (9).

6. The energy storage system for porous reservoirs according to claim 1, characterized in that, The separation module includes: The buffer desander (7) is connected to the third end of the injection-production well pipe (4) through the air outlet pipe and is used to remove sand particles entrained in the compressed air. The gas-liquid separator (8) is connected between the buffer sand remover (7) and the air expansion module through the air outlet pipe, and is used to remove liquid entrained in the compressed air.

7. The energy storage system for porous reservoirs according to claim 6, characterized in that, The bottom of the buffer sand remover (7) is the air inlet and the top is the exhaust outlet; The bottom of the buffer desander (7) is filled with a liquid working medium that has a sticking effect on sand particles; A baffle structure is provided on the top of the buffer desander (7) to block the entrained liquid working medium and sand particles.

8. The energy storage system for porous reservoirs according to claim 1, characterized in that, The directional well (5) penetrates the underground porous reservoir horizontally or at a set angle for a set length, and the horizontal well pipe is densely covered with holes for gas flow.

9. The energy storage system for porous reservoirs according to claim 1, characterized in that, Also includes: A gas detection device is installed at the exhaust end of the air expansion module to detect the content of combustible pollutants in the exhaust gas. The exhaust gas treatment device is connected to the exhaust end of the air expansion module and is used to treat combustible pollutants in the exhaust gas.

10. The energy storage system for porous reservoirs according to any one of claims 1 to 9, characterized in that, Also includes: The first valve body (13) is located at the exhaust end of the intake pipe; The second valve body (14) is located at the air inlet end of the air outlet pipeline.

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