Coordination system and method for carbon dioxide salt water layer storage and underground hydrogen storage

Abstract

The invention relates to the technical field of oilfield development, and discloses a carbon dioxide salt water layer sealing and underground hydrogen storage coordination system and method.The method mainly comprises the steps that when hydrogen is collected, hydrogen is extracted from a hydrogen storage area through a first shaft, and meanwhile carbon dioxide is injected into a salt water layer from the earth surface through a second shaft; carbon dioxide is stored around the hydrogen storage area to form a carbon dioxide storage area; wherein the hydrogen storage area is not communicated with the carbon dioxide storage area, and the storage front edge of the carbon dioxide storage area drives water flow of the salt water layer to flow towards the hydrogen storage area when expanding, so that the storage front edge of the hydrogen storage area shrinks towards the first shaft. Therefore, energy is provided for hydrogen recovery by utilizing pressure accumulation and underground water flow caused by carbon dioxide injection, economic benefits can be created for carbon dioxide salt water layer storage, the use of cushion gas in underground hydrogen storage can be reduced, and the risk of mixing of hydrogen and cushion gas can be reduced, so that the operation cost of underground hydrogen storage is reduced, and the energy efficiency of underground hydrogen storage is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield development, and in particular to a coordination system for carbon dioxide saline aquifer sealing and underground hydrogen storage and a coordination method for carbon dioxide saline aquifer sealing and underground hydrogen storage. Background Art

[0003] Underground hydrogen storage technology is to store the excess energy in the form of hydrogen underground when energy consumption is lower than the production period, and take it out for use when energy consumption is higher than production. This technology can balance energy demand and supply, improve economic and energy efficiency, and has high safety. Aquifers are one of the ideal target reservoirs for this technology due to their wide distribution. However, compared with hydrogen storage in salt caverns and depleted oil and gas reservoirs, hydrogen storage in aquifers requires more cushion gas, which increases costs. In addition, the mixture of cushion gas and hydrogen will also reduce energy efficiency. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems in the related art to a certain extent. To this end, the first purpose of the present invention is to propose a coordinated system for carbon dioxide saline aquifer storage and underground hydrogen storage, which uses the pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater to provide energy for the production of hydrogen, can create economic benefits for carbon dioxide saline aquifer storage, and can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0005] A second object of the present invention is to provide a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage.

[0006] To achieve the above-mentioned objectives, an embodiment of the first aspect of the present invention proposes a coordinated system for carbon dioxide saline aquifer storage and underground hydrogen storage, comprising: a first wellbore, the first wellbore is established between the saline aquifer and the surface in the target area, and is used to inject hydrogen from the surface into the saline aquifer and to produce hydrogen from the saline aquifer to the surface; a second wellbore, the second wellbore is established between the saline aquifer and the surface, and is used to inject carbon dioxide from the surface into the saline aquifer; when the first wellbore produces hydrogen from the saline aquifer to the surface, the second wellbore injects carbon dioxide from the surface into the saline aquifer.

[0007] In addition, the coordinated system for carbon dioxide saline layer storage and underground hydrogen storage according to the above embodiment of the present invention may also have the following additional technical features:

[0008] According to some embodiments of the present invention, a first pipeline and a second pipeline are provided at the wellhead of the first wellbore, the first pipeline is provided with a first valve, and the second pipeline is provided with a second valve; the first valve is used to control the conduction or cutoff of the first pipeline, and the first pipeline is used to extract groundwater from the saline water layer to the surface; the second valve is used to control the conduction or cutoff of the second pipeline, and the second pipeline is used to inject hydrogen from the surface into the saline water layer and to extract hydrogen from the saline water layer to the surface.

[0009] According to some embodiments of the present invention, a third pipeline is provided at the wellhead of the second wellbore, and the third pipeline is provided with a third valve; the third valve is used to control the conduction or cutoff of the third pipeline, and the third pipeline is used to inject carbon dioxide from the surface into the saline layer.

[0010] According to an embodiment of the present invention, the coordinated system for carbon dioxide saltwater layer storage and underground hydrogen storage includes: a first wellbore, the first wellbore is established between the saltwater layer and the surface of the target area, and is used to inject hydrogen from the surface into the saltwater layer and to extract hydrogen from the saltwater layer to the surface; a second wellbore, the second wellbore is established between the saltwater layer and the surface, and is used to inject carbon dioxide from the surface into the saltwater layer; when the first wellbore extracts hydrogen from the saltwater layer to the surface, the second wellbore injects carbon dioxide from the surface into the saltwater layer. Thus, the system uses the pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater to provide energy for the extraction of hydrogen, which can create economic benefits for the storage of carbon dioxide saltwater layers, and can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0011] The second purpose of the present invention is to propose a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage, which utilizes the pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater to provide energy for the production of hydrogen, thereby creating economic benefits for carbon dioxide saline aquifer storage, and reducing the use of cushion gas in underground hydrogen storage, reducing the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0012] To achieve the above-mentioned purpose, the second aspect of the present invention proposes a method for coordinating the storage of carbon dioxide in a saline aquifer and underground hydrogen storage, which is applied to the above-mentioned coordination system for the storage of carbon dioxide in a saline aquifer and underground hydrogen storage, including: when hydrogen is initially collected, hydrogen is extracted from a hydrogen storage area through a first wellbore, and at the same time, carbon dioxide is injected into the saline aquifer from the surface through a second wellbore, so that carbon dioxide is stored around the hydrogen storage area to form a carbon dioxide storage area; wherein the hydrogen storage area is not connected to the carbon dioxide storage area, and the storage front of the carbon dioxide storage area drives the water flow of the saline aquifer toward the hydrogen storage area when expanding, so that the storage front of the hydrogen storage area shrinks toward the first wellbore.

[0013] In addition, the coordination method for carbon dioxide saline aquifer storage and underground hydrogen storage according to the above embodiment of the present invention may also have the following additional technical features:

[0014] According to some embodiments of the present invention, before the initial collection of hydrogen, the above method also includes: arranging a first wellbore and a second wellbore between the saline water layer and the surface of the target area; before the initial storage of hydrogen, extracting groundwater from the saline water layer to the surface through the first wellbore to form a first pore space in the saline water layer; injecting hydrogen into the first pore space through the first wellbore to store hydrogen in the first pore space to form a hydrogen storage area.

[0015] According to some embodiments of the present invention, the above method also includes: when storing hydrogen again, injecting hydrogen into the hydrogen storage area through the first wellbore; wherein, when the storage front of the hydrogen storage area expands, the storage front drives the water flow of the saline layer toward the carbon dioxide storage area, so that the carbon dioxide stored in the carbon dioxide storage area moves away from the hydrogen storage area.

[0016] According to some embodiments of the present invention, before the initial storage of hydrogen, groundwater is extracted from the saline water layer to the surface through the first wellbore to form a first pore space in the saline water layer, including: controlling the first valve to open, the second valve and the third valve to close, so that the first pipeline is connected, the second pipeline and the third pipeline are blocked, and groundwater is extracted from the saline water layer to the surface through the first pipeline.

[0017] According to some embodiments of the present invention, when hydrogen is stored for the first time, hydrogen is injected into the first pore space through the first wellbore, including: controlling the second valve to open, the first valve and the third valve to close, so that the second pipeline is connected, the first pipeline and the third pipeline are blocked, and hydrogen is injected into the first pore space through the second pipeline.

[0018] According to some embodiments of the present invention, when hydrogen is initially collected, hydrogen is collected from the hydrogen storage area through the first wellbore, and carbon dioxide is injected from the surface into the saline layer through the second wellbore, including: controlling the first valve to close, the second valve and the third valve to open, so that the first pipeline is cut off and the second pipeline and the third pipeline are connected, hydrogen is collected from the hydrogen storage area through the second pipeline, and carbon dioxide is injected from the surface into the saline layer through the third pipeline.

[0019] According to some embodiments of the present invention, when hydrogen is stored again, hydrogen is injected into the hydrogen storage area through the first wellbore, including: controlling the second valve to open, the first valve and the third valve to close, so that the second pipeline is connected, the first pipeline and the third pipeline are cut off, and hydrogen is injected into the hydrogen storage area through the second pipeline.

[0020] According to the coordinated method of carbon dioxide saltwater layer sealing and underground hydrogen storage in an embodiment of the present invention, the method includes: when collecting hydrogen for the first time, hydrogen is extracted from the hydrogen storage area through the first wellbore, and carbon dioxide is injected from the surface into the saltwater layer through the second wellbore, so that carbon dioxide is stored around the hydrogen storage area to form a carbon dioxide storage area; wherein the hydrogen storage area is not connected to the carbon dioxide storage area, and the storage front edge of the carbon dioxide storage area drives the water flow of the saltwater layer toward the hydrogen storage area when expanding, so that the storage front edge of the hydrogen storage area shrinks toward the first wellbore. Thus, the method uses the pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater to provide energy for the extraction of hydrogen, which can create economic benefits for the sealing of carbon dioxide saltwater layers, and can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0021] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 A schematic diagram of a coordinated system for carbon dioxide saline aquifer storage and underground hydrogen storage according to some embodiments of the present invention;

[0023] Figure 2 A flow chart of a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage according to some embodiments of the present invention;

[0024] Figure 3 One of the schematic diagrams of the coordinated method of carbon dioxide saline aquifer sequestration and underground hydrogen storage according to some embodiments of the present invention;

[0025] Figure 4 A second schematic diagram of a coordinated method for carbon dioxide saline layer storage and underground hydrogen storage according to some embodiments of the present invention;

[0026] Figure 5 Schematic diagram of the third method for coordinating carbon dioxide saline aquifer storage and underground hydrogen storage according to some embodiments of the present invention;

[0027] Figure 6 A fourth schematic diagram of a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage according to some embodiments of the present invention;

[0028] Figure 7 A schematic diagram of a coordinated system for carbon dioxide saline aquifer storage and underground hydrogen storage according to other embodiments of the present invention;

[0029] Figure 8 Schematic diagram 5 of a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage according to some embodiments of the present invention;

[0030] Fig. 9 Schematic diagram No. 6 of a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage according to some embodiments of the present invention;

[0031] Fig.10 Schematic diagram seven of the coordinated method of carbon dioxide saline aquifer sequestration and underground hydrogen storage according to some embodiments of the present invention.

[0032] Description of Reference Numerals

[0033] 1-saltwater layer, 2-first wellbore, 3-second wellbore, 4-third wellbore, 5-fourth wellbore, 6-fifth wellbore, 7-first pipeline, 8-second pipeline, 9-third pipeline, 10-fourth pipeline, 11-fifth pipeline, 12-sixth pipeline, 13-first valve, 14-second valve, 15-third valve, 16-fourth valve, 17-fifth valve, 18-sixth valve, 19-hydrogen storage area, 20-storage front edge of hydrogen storage area, 21-carbon dioxide storage area, 22-storage front edge of carbon dioxide storage area, 23-groundwater isolation Area, 24-precipitation funnel, 25-fluid migration direction, 1a-embodiment saline layer, 2a-embodiment first wellbore, 3a-embodiment second wellbore, 4a-embodiment third wellbore, 5a-embodiment fourth wellbore, 7a-embodiment first pipeline, 8a-embodiment second pipeline, 9a-embodiment third pipeline, 10a-embodiment fourth pipeline, 11a-embodiment fifth pipeline, 13a-embodiment first valve, 14a-embodiment second valve, 15a-embodiment third valve, 16a-embodiment fourth valve, 17a-embodiment fifth valve. DETAILED DESCRIPTION

[0034] In order to make the objectives, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with specific embodiments and with reference to the accompanying drawings.

[0035] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0036] As mentioned in the background technology section, geological storage of carbon dioxide is one of the important technologies for achieving my country's carbon neutrality goal. It is committed to injecting carbon dioxide captured from industrial waste gas or the atmosphere into underground reservoirs to achieve long-term isolation from the atmosphere. Among them, saline layers have become one of the most promising target reservoirs due to their huge reserves. However, compared with the use of carbon dioxide to enhance oil and gas recovery, carbon dioxide storage in saline layers has almost no economic benefits other than carbon emission reduction, which has hindered its industrialization process.

[0037] In addition, underground hydrogen storage technology is to store the excess energy in the form of hydrogen underground when energy consumption is lower than the production period, and take it out for use when energy consumption is higher than production. This technology can balance energy demand and supply, improve economic and energy efficiency, and has high safety. Aquifers are one of the ideal target reservoirs for this technology due to their wide distribution. However, compared with hydrogen storage in salt caverns and depleted oil and gas reservoirs, hydrogen storage in aquifers requires more cushion gas, which increases costs. In addition, the mixture of cushion gas and hydrogen will also reduce energy efficiency.

[0038] Therefore, the present invention utilizes the pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater to provide energy for the extraction of hydrogen, which can create economic benefits for the storage of carbon dioxide in saline layers, and can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing of hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0039] The following describes, with reference to the accompanying drawings, a coordinated system for carbon dioxide saline aquifer storage and underground hydrogen storage and a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage proposed in embodiments of the present invention.

[0040] refer to Figure 1 , is a schematic diagram of a coordinated system for carbon dioxide saline aquifer sequestration and underground hydrogen storage according to some embodiments of the present invention.

[0041] The coordinated system 100 for carbon dioxide saline aquifer storage and underground hydrogen storage of the present invention may include a first wellbore 2 and a second wellbore 3 .

[0042] The first wellbore 2 is established between the saline water layer 1 and the surface of the target area. The first wellbore 2 is used to inject hydrogen from the surface into the saline water layer 1 and to extract hydrogen from the saline water layer 1 to the surface. The portion of the first wellbore 2 located in the saline water layer 1 is perforated to connect the first wellbore 2 with the saline water layer 1.

[0043] A first pipeline 7 and a second pipeline 8 are provided at the wellhead of the first wellbore 2. The first pipeline 7 is provided with a first valve 13, and the second pipeline 8 is provided with a second valve 14. The first valve 13 is used to control the conduction or cutoff of the first pipeline 7, and the first pipeline 7 is used to extract groundwater from the saline layer 1 to the surface; the second valve 14 is used to control the conduction or cutoff of the second pipeline 8, and the second pipeline 8 is used to inject hydrogen from the surface to the saline layer 1 and to extract hydrogen from the saline layer 1 to the surface. When it is necessary to extract groundwater to the surface, the first pipeline 7 is controlled to be conducted; when it is not necessary to extract groundwater to the surface, the first pipeline 7 is controlled to be cut off. When it is necessary to inject hydrogen into the saline layer 1 and to extract hydrogen from the saline layer 1 to the surface, the second pipeline 8 is controlled to be conducted; when it is not necessary to inject hydrogen into the saline layer 1 and to extract hydrogen from the saline layer 1 to the surface, the second pipeline 8 is controlled to be cut off.

[0044] The second wellbore 3 is established between the saline water layer 1 and the ground surface. The second wellbore 3 is used to inject carbon dioxide from the ground surface into the saline water layer 1. The portion of the second wellbore 3 located in the saline water layer 1 is perforated to connect the second wellbore 3 with the saline water layer 1.

[0045] A third pipeline 9 is provided at the wellhead of the second wellbore 3. The third pipeline 9 is provided with a third valve 15. The third valve 15 is used to control the conduction or cutoff of the third pipeline 9. The third pipeline 9 is used to inject carbon dioxide from the surface into the saline water layer 1. When carbon dioxide needs to be injected into the saline water layer 1, the third pipeline 9 is controlled to be conducted; when carbon dioxide does not need to be injected into the saline water layer 1, the third pipeline 9 is controlled to be cut off.

[0046] When the first wellbore 2 extracts hydrogen from the saline layer 1 to the surface, the second wellbore 3 injects carbon dioxide from the surface into the saline layer 1. The pressure accumulation caused by the injection of carbon dioxide and the groundwater flow are used to provide energy for the extraction of hydrogen. This can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing of hydrogen and cushion gas, reduce the operating cost of underground hydrogen storage, and improve the energy efficiency of underground hydrogen storage.

[0047] As a specific example, continue to refer to Figure 1 The coordinated system 100 for carbon dioxide saline layer storage and underground hydrogen storage of the present invention may further include a third wellbore 4 , a fourth wellbore 5 and a fifth wellbore 6 .

[0048] The third wellbore 4 is established between the saline water layer 1 and the ground surface, and is used to inject carbon dioxide from the ground surface into the saline water layer 1 . The portion of the third wellbore 4 located in the saline water layer 1 is perforated to connect the third wellbore 4 with the saline water layer 1 .

[0049] A fourth pipeline 10 is provided at the wellhead of the third wellbore 4. The fourth pipeline 10 is provided with a fourth valve 16. The fourth valve 16 is used to control the conduction or cutoff of the fourth pipeline 10. The fourth pipeline 10 is used to inject carbon dioxide from the surface into the saline water layer 1. When carbon dioxide needs to be injected into the saline water layer 1, the fourth pipeline 10 is controlled to be conducted; when carbon dioxide does not need to be injected into the saline water layer 1, the fourth pipeline 10 is controlled to be cut off.

[0050] The fourth wellbore 5 is built between the saline water layer 1 and the ground surface, and is used to inject carbon dioxide from the ground surface into the saline water layer 1 . The portion of the fourth wellbore 5 located in the saline water layer 1 is perforated to connect the fourth wellbore 5 with the saline water layer 1 .

[0051] A fifth pipeline 11 is provided at the wellhead of the fourth wellbore 5. The fifth pipeline 11 is provided with a fifth valve 17. The fifth valve 17 is used to control the conduction or cutoff of the fifth pipeline 11. The fifth pipeline 11 is used to inject carbon dioxide from the surface into the saline water layer 1. When carbon dioxide needs to be injected into the saline water layer 1, the fifth pipeline 11 is controlled to be conducted; when carbon dioxide does not need to be injected into the saline water layer 1, the fifth pipeline 11 is controlled to be cut off.

[0052] The fifth wellbore 6 is established between the saline water layer 1 and the ground surface, and is used to inject carbon dioxide from the ground surface into the saline water layer 1 . The portion of the fifth wellbore 6 located in the saline water layer 1 is perforated to connect the fifth wellbore 6 with the saline water layer 1 .

[0053] A sixth pipeline 12 is provided at the wellhead of the fifth wellbore 6. The sixth pipeline 12 is provided with a sixth valve 18. The sixth valve 18 is used to control the conduction or cutoff of the sixth pipeline 12. The sixth pipeline 12 is used to inject carbon dioxide from the surface into the saline water layer 1. When carbon dioxide needs to be injected into the saline water layer 1, the sixth pipeline 12 is controlled to be conducted; when carbon dioxide does not need to be injected into the saline water layer 1, the sixth pipeline 12 is controlled to be cut off.

[0054] When the first wellbore 2 extracts hydrogen from the saline layer 1 to the surface, the second wellbore 3, the third wellbore 4, the fourth wellbore 5 and the fifth wellbore 6 inject carbon dioxide from the surface into the saline layer 1, and the pressure accumulation caused by the injection of carbon dioxide and the groundwater flow are used to provide energy for the extraction of hydrogen. This can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing of hydrogen and cushion gas, reduce the operating cost of underground hydrogen storage, and improve the energy efficiency of underground hydrogen storage.

[0055] It needs to be explained that the specific number and distribution pattern of the second wellbore 3, the third wellbore 4, the fourth wellbore 5 and the fifth wellbore 6 need to be optimized and adjusted according to the actual geological conditions and hydrogen reserves. The principle is to ensure that the hydrogen storage area 19 in the saline layer 1 is always located within the confined space of the carbon dioxide storage area 21, and the groundwater isolation area 23 between the storage front 20 of the hydrogen storage area and the storage front 22 of the carbon dioxide storage area always exists during the operation of the project.

[0056] In summary, the coordinated system for carbon dioxide saltwater layer storage and underground hydrogen storage according to an embodiment of the present invention includes: a first wellbore, the first wellbore is established between the saltwater layer and the surface of the target area, and is used to inject hydrogen from the surface into the saltwater layer and to extract hydrogen from the saltwater layer to the surface; a second wellbore, the second wellbore is established between the saltwater layer and the surface, and is used to inject carbon dioxide from the surface into the saltwater layer; when the first wellbore extracts hydrogen from the saltwater layer to the surface, the second wellbore injects carbon dioxide from the surface into the saltwater layer. Therefore, this system uses the pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater to provide energy for the extraction of hydrogen, which can create economic benefits for the storage of carbon dioxide in saltwater layers, and can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0057] refer to Figure 2 , which is a flow chart of a coordinated method for carbon dioxide saline aquifer sequestration and underground hydrogen storage according to some embodiments of the present invention.

[0058] like Figure 2 As shown, the coordinated method for carbon dioxide saline layer storage and underground hydrogen storage in an embodiment of the present invention may include the following steps:

[0059] When hydrogen is collected for the first time, hydrogen is extracted from the hydrogen storage area through the first wellbore, and at the same time, carbon dioxide is injected from the surface into the saline water layer through the second wellbore, so that the carbon dioxide is stored around the hydrogen storage area to form a carbon dioxide storage area; wherein the hydrogen storage area is not connected to the carbon dioxide storage area, and the storage front of the carbon dioxide storage area drives the water flow of the saline water layer toward the hydrogen storage area when expanding, so that the storage front of the hydrogen storage area shrinks toward the first wellbore.

[0060] Specifically, refer to Figure 3, is one of the schematic diagrams of the coordinated method of carbon dioxide saltwater layer sealing and underground hydrogen storage according to some embodiments of the present invention. When hydrogen is first collected, the second valve and the third valve are opened, hydrogen is extracted from the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore, and carbon dioxide is injected from the surface to the saltwater layer at a certain flow rate through the third pipeline of the second wellbore, so that carbon dioxide is stored around the hydrogen storage area to form a funnel-shaped carbon dioxide storage area in the saltwater layer. The hydrogen storage area is not connected to the carbon dioxide storage area, and the carbon dioxide storage area also has a storage front. The storage front of the carbon dioxide storage area drives the groundwater in the saltwater layer to flow toward the direction of the hydrogen storage area of ​​the first wellbore when expanding, and then drives the hydrogen in the hydrogen storage area to flow out along the first wellbore, so that the hydrogen storage area gradually shrinks, and the storage front of the hydrogen storage area gradually shrinks toward the first wellbore. When the hydrogen production reaches the set value, the second valve and the third valve are closed. It is possible to combine carbon dioxide saline aquifer storage with underground hydrogen storage, so that the two can work synergistically in the same layer of water isolation. During the hydrogen production process, the carbon dioxide injection is started to achieve permanent carbon dioxide saline aquifer storage and intermittent underground hydrogen storage. The pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater are used to provide energy for the production of hydrogen, thereby creating economic benefits for carbon dioxide saline aquifer storage. At the same time, the cost of underground hydrogen storage is reduced by reducing the use of cushion gas and pumping energy. The carbon dioxide storage area and the hydrogen storage area in the saline aquifer are isolated by groundwater, which effectively reduces the risk of hydrogen and carbon dioxide mixing.

[0061] In some embodiments of the present invention, before the initial collection of hydrogen, the above method also includes: arranging a first wellbore and a second wellbore between the saline water layer and the surface of the target area; before the initial storage of hydrogen, extracting groundwater from the saline water layer to the surface through the first wellbore to form a first pore space in the saline water layer; injecting hydrogen into the first pore space through the first wellbore to store hydrogen in the first pore space to form a hydrogen storage area.

[0062] Specifically, refer to Figure 4 , which is a second schematic diagram of a coordinated method for carbon dioxide saline aquifer storage and underground hydrogen storage according to some embodiments of the present invention, wherein a first wellbore is established between the saline aquifer and the surface of the target area, and the first wellbore injects hydrogen from the surface into the saline aquifer and extracts hydrogen from the saline aquifer to the surface. A second wellbore is established between the saline aquifer and the surface, and the second wellbore injects carbon dioxide from the surface into the saline aquifer.

[0063] Before the initial storage of hydrogen, the second valve and the third valve are closed, the first valve is opened, and a certain amount of groundwater is extracted from the saline water layer to the surface through the first pipeline of the first wellbore. After the groundwater is extracted, the first valve is closed. The amount of groundwater extracted can be determined in combination with the working conditions and engineering requirements. A precipitation funnel is formed around the first wellbore in the saline water layer to provide a first pore space for the subsequent storage of hydrogen.

[0064] refer to Figure 5 , which is a third schematic diagram of a coordinated method for carbon dioxide saltwater layer sealing and underground hydrogen storage according to some embodiments of the present invention. When hydrogen is initially stored, the second valve is opened, and hydrogen is injected into the first pore space of the saltwater layer through the second pipeline of the first wellbore at a certain flow rate, so that hydrogen is stored in the first pore space, so as to form a funnel-shaped hydrogen storage area in the saltwater layer, and the hydrogen storage area has a storage front edge. When the injection amount of hydrogen reaches the set injection amount, the second valve is closed, wherein the flow rate of the injected hydrogen needs to be determined according to the hydrogen reserves and storage cycle, the breakthrough pressure of the caprock, etc. In some embodiments, the third wellbore is established between the saltwater layer and the surface, and the third wellbore injects carbon dioxide from the surface into the saltwater layer. The fourth wellbore is established between the saltwater layer and the surface, and the fourth wellbore injects carbon dioxide from the surface into the saltwater layer. The fifth wellbore is established between the saltwater layer and the surface, and the fifth wellbore injects carbon dioxide from the surface into the saltwater layer.

[0065] In some embodiments of the present invention, the above method also includes: when storing hydrogen again, injecting hydrogen into the hydrogen storage area through the first wellbore; wherein, when the storage front of the hydrogen storage area expands, the storage front drives the water flow of the saline layer toward the carbon dioxide storage area, so that the carbon dioxide stored in the carbon dioxide storage area moves away from the hydrogen storage area.

[0066] Specifically, refer to Figure 6 , which is a fourth schematic diagram of a coordinated method for carbon dioxide saltwater layer sealing and underground hydrogen storage according to some embodiments of the present invention. When storing hydrogen again, open the second valve and inject hydrogen into the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore, wherein the injection flow rate of hydrogen needs to be determined according to the hydrogen reserves and storage cycle, the breakthrough pressure of the cap rock, etc. The hydrogen injected into the hydrogen storage area through the first wellbore causes the storage front edge of the hydrogen storage area to expand around the first wellbore, driving the groundwater in the saltwater layer to flow toward the direction of the carbon dioxide storage area of ​​the second wellbore, and then driving the carbon dioxide stored in the carbon dioxide storage area to flow toward the direction of the hydrogen storage area away from the first wellbore, causing the carbon dioxide storage area to deform, wherein the carbon dioxide storage area between the second wellbore and the first wellbore becomes smaller, and the carbon dioxide storage area outside the envelope of the second wellbore becomes larger. When the hydrogen injection amount reaches the set value, close the second valve.

[0067] In some embodiments of the present invention, before the initial storage of hydrogen, groundwater is extracted from the saline water layer to the surface through the first wellbore to form a first pore space in the saline water layer, including: controlling the first valve to open, the second valve and the third valve to close, so that the first pipeline is connected, the second pipeline and the third pipeline are blocked, and groundwater is extracted from the saline water layer to the surface through the first pipeline.

[0068] Specifically, before the initial storage of hydrogen, the first valve is controlled to be opened, and the second valve and the third valve are controlled to be closed, so that the first pipeline is conducted and the second pipeline and the third pipeline are blocked, and groundwater is extracted from the saline layer to the surface through the first pipeline of the first wellbore, and a precipitation funnel is formed around the first wellbore in the saline layer to provide a first pore space for subsequent storage of hydrogen. After the groundwater is extracted, the first valve is controlled to be closed to block the first pipeline.

[0069] In some embodiments, before the initial storage of hydrogen, the first valve is controlled to be opened, and the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to be closed, so that the first pipeline is conducted, the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are cut off, and groundwater is extracted from the saline layer to the surface through the first pipeline of the first wellbore, and a precipitation funnel is formed around the first wellbore in the saline layer to provide a first pore space for subsequent storage of hydrogen. After the groundwater is extracted, the first valve is controlled to be closed to cut off the first pipeline.

[0070] In some embodiments of the present invention, when hydrogen is stored for the first time, hydrogen is injected into the first pore space through the first wellbore, including: controlling the second valve to open, the first valve and the third valve to close, so that the second pipeline is connected, the first pipeline and the third pipeline are blocked, and hydrogen is injected into the first pore space through the second pipeline.

[0071] Specifically, when hydrogen is stored for the first time, the second valve is controlled to open, and the first valve and the third valve are controlled to close, so that the second pipeline is connected and the first pipeline and the third pipeline are blocked, and hydrogen is injected into the first pore space through the second pipeline of the first wellbore. When the injection amount of hydrogen reaches the set injection amount, the second valve is controlled to close to block the second pipeline.

[0072] In some embodiments, when hydrogen is initially stored, the second valve is controlled to open, and the first valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to close, so that the second pipeline is connected, the first pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are cut off, and hydrogen is injected into the first pore space through the second pipeline of the first wellbore. When the injection amount of hydrogen reaches the set injection amount, the second valve is controlled to close to cut off the second pipeline.

[0073] In some embodiments of the present invention, when hydrogen is initially collected, hydrogen is collected from the hydrogen storage area through the first wellbore, and carbon dioxide is injected from the surface into the saline layer through the second wellbore, including: controlling the first valve to close, the second valve and the third valve to open, so that the first pipeline is cut off and the second pipeline and the third pipeline are connected, hydrogen is collected from the hydrogen storage area through the second pipeline, and carbon dioxide is injected from the surface into the saline layer through the third pipeline.

[0074] Specifically, when hydrogen is collected for the first time, the first valve is controlled to be closed, and the second valve and the third valve are controlled to be opened, so that the first pipeline is cut off and the second pipeline and the third pipeline are connected, hydrogen is extracted from the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore, and at the same time, carbon dioxide is injected from the surface to the saline water layer at a certain flow rate through the third pipeline of the second wellbore, so that carbon dioxide is stored around the hydrogen storage area to form a funnel-shaped carbon dioxide storage area in the saline water layer. When the hydrogen production reaches the set value, the second valve and the third valve are controlled to be closed to cut off the second pipeline and the third pipeline.

[0075] In some embodiments, when hydrogen is collected for the first time, the first valve is controlled to be closed, and the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to be opened, so that the first pipeline is cut off, and the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are connected, and hydrogen is produced from the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore, and at the same time, carbon dioxide is injected from the surface to the saline water layer at a certain flow rate through the third pipeline of the second wellbore, the fourth pipeline of the third wellbore, the fifth pipeline of the fourth wellbore, and the sixth pipeline of the fifth wellbore, so that carbon dioxide is stored around the hydrogen storage area to form a funnel-shaped carbon dioxide storage area in the saline water layer. When the hydrogen production reaches the set value, the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to be closed, so that the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are cut off.

[0076] In some embodiments of the present invention, when storing hydrogen again, hydrogen is injected into the hydrogen storage area through the first wellbore, including: controlling the second valve to open, the first valve and the third valve to close, so that the second pipeline is connected, the first pipeline and the third pipeline are cut off, and hydrogen is injected into the hydrogen storage area through the second pipeline.

[0077] Specifically, when storing hydrogen again, the second valve is controlled to open, and the first valve and the third valve are controlled to close, so that the second pipeline is connected and the first pipeline and the third pipeline are blocked, and hydrogen is injected into the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore. When the hydrogen injection amount reaches the set value, the second valve is controlled to close to block the second pipeline.

[0078] In some embodiments, when storing hydrogen again, the second valve is controlled to open, and the first valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to close, so that the second pipeline is connected, the first pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are cut off, and hydrogen is injected into the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore. When the hydrogen injection amount reaches the set value, the second valve is controlled to close to cut off the second pipeline.

[0079] In some embodiments, the first valve is controlled to be closed when hydrogen is collected for the first time, and the second valve and the third valve are controlled to be opened, so that the first pipeline is cut off and the second pipeline and the third pipeline are connected, hydrogen is extracted from the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore, and carbon dioxide is injected from the surface to the saline layer at a certain flow rate through the third pipeline of the second wellbore, so that carbon dioxide is stored around the hydrogen storage area to form a funnel-shaped carbon dioxide storage area in the saline layer, and when the hydrogen production reaches a set value, the second valve and the third valve are controlled to be closed, so that the second pipeline and the third pipeline are cut off. And when hydrogen is stored again, the second valve is controlled to be opened, and the first valve and the third valve are controlled to be closed, so that the second pipeline is connected, the first pipeline and the third pipeline are cut off, hydrogen is injected into the hydrogen storage area at a certain flow rate through the second pipeline of the first wellbore, and when the hydrogen injection amount reaches a set value, the second valve is controlled to be closed, so that the second pipeline is cut off. Permanent carbon dioxide aquifer storage and intermittent underground hydrogen storage can be achieved. In the process, the pressure accumulation and groundwater flow caused by the injection of carbon dioxide provide energy for the extraction of hydrogen, creating economic benefits for carbon dioxide aquifer storage, and reducing the use of cushion gas in underground hydrogen storage, reducing the risk of mixing of hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0080] Combination Figure 1-Figure 6 For specific embodiment 1:

[0081] The target saline layer is horizontally distributed, homogeneous and isotropic, with a porosity of 20%, a burial depth of 800m, a layer thickness of 50m, a hydrostatic pressure of 8MPa, a formation temperature of 45°C, and an underground hydrogen storage period of 1 year, including 6 months of gas injection, 3 months of well shutdown, and 3 months of gas production. The designed maximum reserves are 2,000 tons and the maximum operating pressure is 10MPa.

[0082] According to the following formula, it can be estimated that hydrogen will occupy 3.42x10 5 m 3 The pore space is 1.715x10 6 m 3 of stratum volume.

[0083]

[0084] Among them, V pore1 is the pore volume occupied by hydrogen, in m 3 ; V res1 is the volume of the formation occupied by hydrogen, in m 3 ; φ 1 is the porosity of the saline layer; is the designed hydrogen reserve, in kg; is the density of hydrogen at the temperature and pressure of the saltwater layer; in this embodiment, the density of hydrogen at the temperature (45°C) and pressure (8MPa) is 5.83kg / m 3 .

[0085] Continue to refer Figure 1 A first wellbore, a second wellbore, a third wellbore, a fourth wellbore and a fifth wellbore are arranged between the saline water layer and the surface of the target area, the first wellbore is used to inject hydrogen from the surface into the saline water layer and to extract hydrogen from the saline water layer to the surface, the second wellbore is used to inject carbon dioxide from the surface into the saline water layer, the third wellbore is used to inject carbon dioxide from the surface into the saline water layer, the fourth wellbore is used to inject carbon dioxide from the surface into the saline water layer, and the fifth wellbore is used to inject carbon dioxide from the surface into the saline water layer, wherein the first wellbore is located within the confined space of the second wellbore, the third wellbore, the fourth wellbore and the fifth wellbore.

[0086] A first pipe and a second pipe are provided at the wellhead of the first wellbore, the first pipe is provided with a first valve, and the second pipe is provided with a second valve; a third pipe is provided at the wellhead of the second wellbore, the third pipe is provided with a third valve; a fourth pipe is provided at the wellhead of the third wellbore, the fourth pipe is provided with a fourth valve; a fifth pipe is provided at the wellhead of the fourth wellbore, the fifth pipe is provided with a fifth valve; a sixth pipe is provided at the wellhead of the fifth wellbore, the sixth pipe is provided with a sixth valve. The first wellbore, the second wellbore, the third wellbore, the fourth wellbore and the fifth wellbore are partially perforated in the saline water layer, so that the first wellbore, the second wellbore, the third wellbore, the fourth wellbore and the fifth wellbore are connected to the saline water layer. Among them, the horizontal well spacing between the first wellbore and the second wellbore, the third wellbore, the fourth wellbore and the fifth wellbore is set to 500m. The well spacing of 500m can ensure that the volume of the confined space of the second wellbore, the third wellbore, the fourth wellbore and the fifth wellbore is larger than the volume of the space occupied by hydrogen in the saline aquifer, and avoid the carbon dioxide and hydrogen injected into the saline aquifer breaking through the groundwater and mixing.

[0087] Continue to refer Figure 4 Before the initial storage of hydrogen, the first valve is controlled to open, and the second, third, fourth, fifth and sixth valves are controlled to close, so that the first pipeline is connected, and the second, third, fourth, fifth and sixth pipelines are cut off, and groundwater is extracted from the saline layer to the surface through the first pipeline of the first wellbore. A precipitation funnel is formed around the first wellbore in the saline layer to provide the first pore space for the subsequent storage of hydrogen. When the extracted groundwater reaches 3.42x10 5 m 3 Afterwards, the first valve is controlled to close so that the first pipeline is cut off.

[0088] Continue to refer Figure 5When hydrogen is initially stored, the second valve is controlled to be opened, and the first valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to be closed, so that the second pipeline is conducted, the first pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are cut off, and hydrogen is injected into the first pore space through the second pipeline of the first wellbore at an average flow rate of 11.1 kg / day, so that hydrogen is stored in the first pore space, so as to form a hydrogen storage area in the shape of a precipitation funnel in the saline layer, and the hydrogen storage area has a storage front. After the hydrogen injection time is 6 months, that is, when the hydrogen injection amount reaches 2,000 tons, the second valve is controlled to be closed to cut off the second pipeline.

[0089] Continue to refer Figure 3 When hydrogen is first collected (3 months after the well is shut down), the first valve is controlled to be closed, and the second valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to be opened, so that the first pipeline is cut off, and the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are connected, and hydrogen is extracted from the hydrogen storage area at an average flow rate of 22.2 kg / day through the second pipeline of the first wellbore, and carbon dioxide is injected from the surface to the saline water layer through the third pipeline of the second wellbore, the fourth pipeline of the third wellbore, the fifth pipeline of the fourth wellbore, and the sixth pipeline of the fifth wellbore at a flow rate of 4 kg / s, respectively, so that carbon dioxide is stored around the hydrogen storage area to form a funnel-shaped carbon dioxide storage area in the saline water layer, the hydrogen storage area is not connected to the carbon dioxide storage area, and the carbon dioxide storage area also has a storage front edge. When the storage front edge of the carbon dioxide storage area expands, it drives the groundwater in the saline water layer to flow toward the direction of the hydrogen storage area of ​​the first wellbore, thereby driving the hydrogen in the hydrogen storage area to flow out along the first wellbore, so that the hydrogen storage area gradually shrinks, and the storage front edge of the hydrogen storage area gradually shrinks toward the first wellbore. After the hydrogen production time reaches 3 months, that is, when the hydrogen production volume reaches the set value, the second valve, the third valve, the fourth valve, the fifth valve and the sixth valve are controlled to be closed to cut off the second pipeline, the third pipeline, the fourth pipeline, the fifth pipeline and the sixth pipeline.

[0090] Continue to refer Figure 6When storing hydrogen again, the second valve is controlled to open, and the first valve, the third valve, the fourth valve, the fifth valve, and the sixth valve are controlled to close, so that the second pipeline is conducted, the first pipeline, the third pipeline, the fourth pipeline, the fifth pipeline, and the sixth pipeline are cut off, and hydrogen is injected into the hydrogen storage area through the second pipeline of the first wellbore at an average flow rate of 11.1 kg / day. The hydrogen injected into the hydrogen storage area through the first wellbore causes the storage front edge of the hydrogen storage area to expand around the first wellbore, driving the groundwater in the saline layer to flow toward the carbon dioxide storage area of ​​the second wellbore, the third wellbore, the fourth wellbore, and the fifth wellbore, thereby driving the carbon dioxide stored in the carbon dioxide storage area to flow toward the direction of the hydrogen storage area away from the first wellbore, causing the carbon dioxide storage area to deform, wherein the carbon dioxide storage area located between the second wellbore, the third wellbore, the fourth wellbore, and the fifth wellbore and the first wellbore becomes smaller, and the carbon dioxide storage area located outside the envelope of the second wellbore, the third wellbore, the fourth wellbore, and the fifth wellbore becomes larger. After the hydrogen injection time reaches 6 months, that is, when the hydrogen injection amount reaches 2,000 tons, the second valve is controlled to close to cut off the second pipeline.

[0091] By repeating the steps of initially collecting hydrogen (three months after the well was shut down) and storing hydrogen again, permanent carbon dioxide aquifer storage and intermittent underground hydrogen storage can be achieved. In this process, the pressure accumulation and groundwater flow caused by the injection of carbon dioxide provide energy for the extraction of hydrogen, creating economic benefits for the carbon dioxide aquifer storage, and reducing the use of cushion gas in underground hydrogen storage, reducing the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0092] Combination Figure 7-Figure 10 For specific embodiment 2:

[0093] The target embodiment saline layer is an inclined stratum with a dip angle of 10°, homogeneous isotropy, a porosity of 20%, a burial depth of 800m, a layer thickness of 50m, a hydrostatic pressure of 8MPa, a formation temperature of 45°C, and an underground hydrogen storage period of 1 year, including 6 months of gas injection, 3 months of well closure, and 3 months of gas production. The designed maximum reserves are 2,000 tons and the maximum operating pressure is 10MPa.

[0094] According to the following formula, it can be estimated that hydrogen will occupy 3.42x10 5 m 3 The pore space is 1.715x10 6 m 3 of stratum volume.

[0095]

[0096] Among them, V pore2 is the pore volume occupied by hydrogen, in m3 ; V res2 is the volume of the formation occupied by hydrogen, in m 3 ; φ 2 is the porosity of the saline layer of the embodiment; is the designed hydrogen reserve, in kg; is the density of hydrogen under the temperature and pressure conditions of the saline layer in the embodiment; the density of hydrogen under the temperature (45°C) and pressure (8MPa) conditions in this embodiment is 5.83kg / m 3 .

[0097] refer to Figure 7 , is a schematic diagram of a coordinated system for carbon dioxide saline aquifer sealing and underground hydrogen storage according to other embodiments of the present invention, wherein a first wellbore 2a, a second wellbore 3a, a third wellbore 4a, and a fourth wellbore 5a are arranged between the saline aquifer 1a of the target area and the surface, the first wellbore 2a of the embodiment is used to inject hydrogen from the surface into the saline aquifer 1a of the embodiment and to produce hydrogen from the saline aquifer 1a of the embodiment to the surface, the second wellbore 3a of the embodiment is used to inject carbon dioxide from the surface into the saline aquifer 1a of the embodiment, the third wellbore 4a of the embodiment is used to inject carbon dioxide from the surface into the saline aquifer 1a of the embodiment, and the fourth wellbore 5a of the embodiment is used to inject carbon dioxide from the surface into the saline aquifer 1a of the embodiment, wherein the first wellbore 2a of the embodiment and the second wellbore 3a of the embodiment are distributed along the inclination direction of the saline aquifer 1a of the embodiment, and the second wellbore 3a of the embodiment is located above the first wellbore 2a of the embodiment, and the third wellbore 4a and the fourth wellbore 5a of the embodiment are located on both sides of the first wellbore 2a of the embodiment.

[0098] The first pipe 7a and the second pipe 8a of the embodiment are arranged at the wellhead of the first wellbore 2a of the embodiment, the first pipe 7a of the embodiment is arranged with the first valve 13a of the embodiment, and the second pipe 8a of the embodiment is arranged with the second valve 14a of the embodiment; the third pipe 9a of the embodiment is arranged at the wellhead of the second wellbore 3a of the embodiment, and the third valve 15a of the embodiment is arranged at the wellhead of the third wellbore 4a of the embodiment; the fourth pipe 10a of the embodiment is arranged at the wellhead of the third wellbore 4a of the embodiment, and the fourth valve 16a of the embodiment is arranged at the wellhead of the fourth wellbore 5a of the embodiment; the fifth pipe 11a of the embodiment is arranged at the wellhead of the fourth wellbore 5a of the embodiment, and the fifth valve 17a of the embodiment is arranged at the fifth wellbore 11a of the embodiment. The first wellbore 2a of the embodiment, the second wellbore 3a of the embodiment, the third wellbore 4a of the embodiment, and the fourth wellbore 5a of the embodiment are perforated in the parts located in the saltwater layer 1a of the embodiment, so that the first wellbore 2a of the embodiment, the second wellbore 3a of the embodiment, the third wellbore 4a of the embodiment, and the fourth wellbore 5a of the embodiment are connected with the saltwater layer 1a of the embodiment. Among them, the horizontal well spacing between the first wellbore 2a of the embodiment and the second wellbore 3a of the embodiment is set to 800m, and the horizontal well spacing between the first wellbore 2a of the embodiment and the third wellbore 4a of the embodiment and the fourth wellbore 5a of the embodiment is set to 400m. The well spacing is set to 800m and 400m to adapt to the upward displacement of the hydrogen injected into the saline water layer 1a of the embodiment along the formation inclination direction due to the buoyancy effect, so as to avoid the carbon dioxide and hydrogen injected into the saline water layer 1a of the embodiment from breaking through the groundwater and mixing. The carbon dioxide injection well is not set below the first wellbore 2a of the embodiment to avoid the carbon dioxide injected into the saline water layer 1a of the embodiment from migrating upward under the action of buoyancy and mixing with the hydrogen injected into the saline water layer 1a of the embodiment. In addition, since the first wellbore 2a of the embodiment is located at a higher terrain than the saline layer 1a of the embodiment, during the process of storing hydrogen, hydrogen will tend to move to the side with higher terrain, so the interaction between the lower end of the first wellbore 2a of the embodiment and the bottom of the first wellbore 2a of the embodiment (i.e., the position where the terrain is lower than the first wellbore 2a of the embodiment) is weakened. Therefore, a carbon dioxide injection well may not be set below the first wellbore 2a of the embodiment (i.e., the position where the terrain is lower than the first wellbore 2a of the embodiment).

[0099] refer to Figure 8, which is a fifth schematic diagram of a coordinated method for storing carbon dioxide in a saline layer and storing hydrogen underground according to some embodiments of the present invention. When storing hydrogen for the first time, the second valve of the embodiment is controlled to be opened, and the first valve, the third valve, the fourth valve, and the fifth valve of the embodiment are controlled to be closed, so that the second pipeline of the embodiment is conducted, the first pipeline of the embodiment, the third pipeline of the embodiment, the fourth pipeline of the embodiment, and the fifth pipeline of the embodiment are cut off, and hydrogen is injected into the first pore space at an average flow rate of 11.1 kg / day through the second pipeline of the embodiment of the first wellbore of the embodiment, so that hydrogen is stored in the first pore space, so as to form an asymmetric embodiment funnel-shaped embodiment hydrogen storage area in the embodiment saline layer, and the embodiment hydrogen storage area has a storage front edge of the embodiment hydrogen storage area. After the injection time of hydrogen is 6 months, that is, when the injection amount of hydrogen reaches 2,000 tons, the second valve of the embodiment is controlled to be closed, so that the second pipeline of the embodiment is cut off.

[0100] refer to Fig. 9 , which is a sixth schematic diagram of a coordinated method for carbon dioxide saline layer sealing and underground hydrogen storage according to some embodiments of the present invention. When hydrogen is first collected (three months after the well is shut down), the first valve of the embodiment is controlled to be closed, and the second valve of the embodiment, the third valve of the embodiment, the fourth valve of the embodiment, and the fifth valve of the embodiment are controlled to be opened, so that the first pipeline of the embodiment is cut off, the second pipeline of the embodiment, the third pipeline of the embodiment, the fourth pipeline of the embodiment, and the fifth pipeline of the embodiment are connected, and hydrogen is extracted from the hydrogen storage area at an average flow rate of 22.2 kg / day through the second pipeline of the embodiment of the first wellbore of the embodiment, and carbon dioxide is injected at a flow rate of 8 kg / s through the third pipeline of the embodiment of the second wellbore of the embodiment, and the fourth pipeline of the embodiment of the third wellbore of the embodiment of the fourth ... The fifth pipeline injects carbon dioxide from the surface into the embodiment saline layer at a flow rate of 4kg / s, so that carbon dioxide is stored around the hydrogen storage area, so as to form the embodiment funnel-shaped embodiment carbon dioxide storage area in the embodiment saline layer, the embodiment hydrogen storage area is not connected to the embodiment carbon dioxide storage area, and the embodiment carbon dioxide storage area also has a storage front edge of the embodiment carbon dioxide storage area. When the storage front edge of the embodiment carbon dioxide storage area expands, it drives the groundwater in the embodiment saline layer to flow toward the embodiment hydrogen storage area of ​​the embodiment first wellbore, thereby driving the hydrogen in the embodiment hydrogen storage area to flow out along the embodiment first wellbore, so that the embodiment hydrogen storage area gradually shrinks, and the storage front edge of the embodiment hydrogen storage area gradually shrinks toward the embodiment first wellbore. After the hydrogen production time reaches 3 months, that is, when the hydrogen production volume reaches the set value, the embodiment second valve, the embodiment third valve, the embodiment fourth valve, and the embodiment fifth valve are controlled to close, so that the embodiment second pipeline, the embodiment third pipeline, the embodiment fourth pipeline, and the embodiment fifth pipeline are cut off.

[0101] refer to Fig.10, which is a schematic diagram of the coordinated method of carbon dioxide saltwater layer sealing and underground hydrogen storage according to some embodiments of the present invention, when storing hydrogen again, the second valve of the embodiment is controlled to open, and the first valve of the embodiment, the third valve of the embodiment, the fourth valve of the embodiment, and the fifth valve of the embodiment are controlled to close, so that the second pipeline of the embodiment is conducted, the first pipeline of the embodiment, the third pipeline of the embodiment, the fourth pipeline of the embodiment, and the fifth pipeline of the embodiment are cut off, and hydrogen is injected into the hydrogen storage area at an average flow rate of 11.1 kg / day through the second pipeline of the embodiment of the first wellbore of the embodiment. The hydrogen injected into the hydrogen storage area through the first wellbore of the embodiment causes the storage front edge of the hydrogen storage area of ​​the embodiment to expand around the first wellbore of the embodiment, driving the groundwater in the saltwater layer of the embodiment to flow toward the direction of the carbon dioxide storage area of ​​the second wellbore of the embodiment, the third wellbore of the embodiment, and the fourth wellbore of the embodiment, thereby driving the carbon dioxide stored in the carbon dioxide storage area to flow toward the direction of the hydrogen storage area away from the first wellbore of the embodiment, wherein the carbon dioxide in the carbon dioxide storage area is simultaneously subjected to the buoyancy and flows upward. After the hydrogen injection time reaches 6 months, that is, when the hydrogen injection amount reaches 2000 tons, the second valve of the embodiment is controlled to close to cut off the second pipeline of the embodiment.

[0102] Repeating the steps of collecting and storing hydrogen can achieve permanent carbon dioxide storage in saline aquifers and intermittent underground hydrogen storage. In this process, the pressure accumulation and groundwater flow caused by the injection of carbon dioxide provide energy for the production of hydrogen, creating economic benefits for the carbon dioxide storage in saline aquifers, and reducing the use of cushion gas in underground hydrogen storage, reducing the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0103] In summary, the coordinated method for carbon dioxide saltwater layer sealing and underground hydrogen storage according to an embodiment of the present invention includes: when hydrogen is first collected, hydrogen is extracted from the hydrogen storage area through the first wellbore, and carbon dioxide is injected from the surface to the saltwater layer through the second wellbore, so that carbon dioxide is stored around the hydrogen storage area to form a carbon dioxide storage area; wherein the hydrogen storage area is not connected to the carbon dioxide storage area, and the storage front of the carbon dioxide storage area drives the water flow of the saltwater layer toward the hydrogen storage area when expanding, so that the storage front of the hydrogen storage area shrinks toward the first wellbore. Thus, this method uses the pressure accumulation caused by the injection of carbon dioxide and the flow of groundwater to provide energy for the extraction of hydrogen, which can create economic benefits for the sealing of carbon dioxide saltwater layers, and can reduce the use of cushion gas in underground hydrogen storage, reduce the risk of mixing hydrogen and cushion gas, thereby reducing the operating cost of underground hydrogen storage and improving the energy efficiency of underground hydrogen storage.

[0104] It should be noted that some embodiments of the present invention are described above. Other embodiments are within the scope of the appended claims. In some cases, the actions or steps recorded in the claims can be performed in an order different from that in the above embodiments and still achieve the desired results. In addition, the processes depicted in the accompanying drawings do not necessarily require the specific order or continuous order shown to achieve the desired results. In some embodiments, multitasking and parallel processing are also possible or may be advantageous.

[0105] In addition, although the operations of the method of the present invention are described in a specific order in the accompanying drawings, this does not require or imply that the operations must be performed in this specific order, or that all the operations shown must be performed to achieve the desired results. On the contrary, the steps depicted in the flow chart can be performed in a different order. Additionally or alternatively, some steps can be omitted, multiple steps can be combined into one step, and / or one step can be decomposed into multiple steps.

[0106] It should be noted that, unless otherwise defined, the technical terms or scientific terms used in the embodiments of the present invention should be understood by people with ordinary skills in the field to which the present invention belongs. The "first", "second" and similar words used in the embodiments of the present invention do not indicate any order, quantity or importance, but are only used to distinguish different components. "Include" or "comprise" and similar words mean that the elements or objects appearing before the word include the elements or objects listed after the word and their equivalents, without excluding other elements or objects. "Connect" or "connected" and similar words are not limited to physical or mechanical connections, but may include electrical connections, whether direct or indirect. "Up", "down", "left", "right" and the like are only used to indicate relative positional relationships. When the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0107] Although the spirit and principle of the present invention have been described with reference to several specific embodiments, it should be understood that the present invention is not limited to the disclosed specific embodiments, and the division of various aspects does not mean that the features in these aspects cannot be combined to benefit, and this division is only for the convenience of expression. The present invention is intended to cover various modifications and equivalent arrangements included in the spirit and scope of the attached claims. The scope of the attached claims conforms to the broadest interpretation, thereby including all such modifications and equivalent structures and functions.

Claims

1. A coordinated system for carbon dioxide saline aquifer storage and underground hydrogen storage, characterized in that: include: A first wellbore (2), the first wellbore (2) being established between the saline water layer (1) in the target area and the ground surface, and being used for injecting hydrogen from the ground surface into the saline water layer (1) and extracting hydrogen from the saline water layer (1) to the ground surface; A second wellbore (3), the second wellbore (3) being established between the saline water layer (1) and the ground surface and being used for injecting carbon dioxide from the ground surface into the saline water layer (1); When the first wellbore (2) extracts hydrogen from the saline water layer (1) to the ground surface, the second wellbore (3) injects carbon dioxide from the ground surface into the saline water layer (1).

2. The coordinated system for carbon dioxide saline layer storage and underground hydrogen storage according to claim 1, characterized in that: A first pipeline (7) and a second pipeline (8) are provided at the wellhead of the first wellbore (2); the first pipeline (7) is provided with a first valve (13), and the second pipeline (8) is provided with a second valve (14); The first valve (13) is used to control the opening or closing of the first pipeline (7), and the first pipeline (7) is used to extract groundwater from the saltwater layer (1) to the surface; The second valve (14) is used to control the opening or closing of the second pipeline (8), and the second pipeline (8) is used to inject hydrogen from the surface into the saline water layer (1) and to extract hydrogen from the saline water layer (1) to the surface.

3. The coordinated system for carbon dioxide saline layer storage and underground hydrogen storage according to claim 1, characterized in that: A third pipeline (9) is provided at the wellhead of the second wellbore (3), and the third pipeline (9) is provided with a third valve (15); The third valve (15) is used to control the opening or closing of the third pipeline (9), and the third pipeline (9) is used to inject carbon dioxide from the surface into the saltwater layer (1).

4. A coordinated method for carbon dioxide saline layer storage and underground hydrogen storage, characterized in that: A coordinated system for carbon dioxide saline aquifer storage and underground hydrogen storage as claimed in any one of claims 1 to 3, comprising: When hydrogen is collected for the first time, hydrogen is extracted from the hydrogen storage area through the first wellbore, and at the same time, carbon dioxide is injected from the surface into the saline water layer through the second wellbore, so that the carbon dioxide is stored around the hydrogen storage area to form a carbon dioxide storage area; wherein the hydrogen storage area is not connected to the carbon dioxide storage area, and the storage front of the carbon dioxide storage area drives the water flow of the saline water layer toward the hydrogen storage area when expanding, so that the storage front of the hydrogen storage area shrinks toward the first wellbore.

5. The coordinated method for carbon dioxide saline layer storage and underground hydrogen storage according to claim 4, characterized in that: Before the initial collection of hydrogen, the method further comprises: Arrange a first wellbore and a second wellbore between a saline layer and the ground surface in a target area; Before initially storing hydrogen, extracting groundwater from the saline water layer to the surface through the first wellbore to form a first pore space in the saline water layer; Hydrogen is injected into the first pore space through the first wellbore so that the hydrogen is stored in the first pore space to form a hydrogen storage area.

6. The coordinated method for carbon dioxide saline layer storage and underground hydrogen storage according to claim 4, characterized in that: The method further comprises: When storing hydrogen again, hydrogen is injected into the hydrogen storage area through the first wellbore; wherein, when the storage front of the hydrogen storage area expands, the water flow of the saltwater layer drives the flow toward the carbon dioxide storage area, so that the carbon dioxide stored in the carbon dioxide storage area moves away from the hydrogen storage area.

7. The coordinated method for carbon dioxide saline layer storage and underground hydrogen storage according to claim 6, characterized in that: Before the initial storage of hydrogen, extracting groundwater from the saline water layer to the surface through the first wellbore to form a first pore space in the saline water layer includes: The first valve is controlled to be opened, and the second valve and the third valve are controlled to be closed, so that the first pipeline is connected, and the second pipeline and the third pipeline are blocked, and groundwater is extracted from the saltwater layer to the surface through the first pipeline.

8. The coordinated method for carbon dioxide saline layer storage and underground hydrogen storage according to claim 7, characterized in that: When storing hydrogen for the first time, injecting hydrogen into the first pore space through the first wellbore comprises: The second valve is controlled to be opened, and the first valve and the third valve are controlled to be closed, so that the second pipeline is connected, and the first pipeline and the third pipeline are blocked, and hydrogen is injected into the first pore space through the second pipeline.

9. The coordinated method for carbon dioxide saline layer storage and underground hydrogen storage according to claim 8, characterized in that: When the hydrogen is initially collected, hydrogen is collected from the hydrogen storage area through the first wellbore, and carbon dioxide is injected from the surface into the saline layer through the second wellbore, including: The first valve is controlled to be closed, and the second valve and the third valve are controlled to be opened, so that the first pipeline is cut off and the second pipeline and the third pipeline are connected, hydrogen is extracted from the hydrogen storage area through the second pipeline, and carbon dioxide is injected from the surface into the saline layer through the third pipeline.

10. The coordinated method for carbon dioxide saline layer storage and underground hydrogen storage according to claim 9, characterized in that: When storing hydrogen again, injecting hydrogen into the hydrogen storage area through the first wellbore includes: The second valve is controlled to be opened, and the first valve and the third valve are controlled to be closed, so that the second pipeline is connected, and the first pipeline and the third pipeline are blocked, and hydrogen is injected into the hydrogen storage area through the second pipeline.

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