A method for storing hydrogen using depleted tight oil and gas reservoirs

Abstract

The present invention discloses a method for storing hydrogen using depleted tight oil and gas reservoirs, which includes the following steps: using the rock formation of a depleted tight oil and gas reservoir after oil and gas production as a hydrogen storage reservoir, continuously injecting hydrogen into the hydrogen storage reservoir through the original horizontal fracturing wells during oil and gas production, and stopping injecting hydrogen after reaching the expected injection volume; when hydrogen is needed, opening the horizontal fracturing wells to start producing hydrogen; over-fracturing is implemented on the horizontal well section of the original horizontal fracturing wells to form a volume fracturing reconstruction area and a non-volume fracturing reconstruction area controlled by fractures. Hydrogen enters the fracturing fractures through the horizontal wellbore and seeps and diffuses into the reservoir. The volume fracturing reconstruction area is the main hydrogen storage area, and the non-volume fracturing reconstruction area is the oil and gas enrichment area, which can serve as a natural barrier for the sealed hydrogen storage space. The present invention can make full use of the existing exploration and development information and the wellbore structure of oil and gas wells, realize the reuse of oil and gas investment, and greatly reduce the hydrogen storage cost.

Description

Technical Field

[0001] The present invention relates to the technical field of storing and releasing hydrogen using underground reservoirs, and particularly to a method for storing hydrogen in depleted tight oil and gas reservoirs. Background Art

[0002] Hydrogen energy technology is an important part of supporting the global energy transition. Hydrogen is a clean and high-quality energy carrier with high energy density per unit mass. The demand for hydrogen is expected to grow rapidly in the current and for a long time to come.

[0003] Safe and efficient hydrogen storage technology is an important link in reducing the cost of the hydrogen energy industry chain. The current mainstream technologies include high-pressure gaseous hydrogen storage, cryogenic liquid hydrogen storage, organic liquid hydrogen storage, and solid material hydrogen storage. High-pressure gaseous hydrogen storage technology is mature and has a simple structure, but has a low hydrogen storage density and poor safety; cryogenic liquid hydrogen storage has a large hydrogen storage density and good safety, but has high energy consumption in the liquefaction process and high requirements for hydrogen storage containers; organic liquid hydrogen storage has high purity and a large hydrogen storage density, but the liquid absorbent has a high cost, high energy consumption in the operation process, and harsh operating space requirements; solid material hydrogen storage is easy to carry and has good safety, but has a low hydrogen storage density per unit mass and low hydrogen charging and discharging efficiency. High operating costs and small hydrogen storage and release volumes are common deficiencies of the above technologies. With the rapid development of the hydrogen energy industry and the substantial increase in hydrogen production, it is inevitable to pursue large-scale hydrogen storage and release that is economical and safe. Developing efficient hydrogen gas storage reservoirs is of great significance.

[0004] Underground hydrogen storage is an important path to achieve large-scale and sustainable hydrogen storage. In addition to low cost and large hydrogen storage volume, small land area and high safety are also the main advantages, including hydrogen storage using salt caverns, mines, underground saline aquifers, and conventional depleted oil and gas reservoirs. Salt cavern hydrogen storage technology is relatively mature, with low reactivity of salt rock with hydrogen and good sealing performance; mine hydrogen storage can make full use of abandoned underground spaces; the geographical distribution of salt caverns and mines is relatively limited, and the sealing performance of the top and bottom layers and surrounding rocks is the key to evaluating whether they are suitable for high-pressure hydrogen storage and release. Underground saline aquifers are widely distributed, which can meet the geographical location requirements for underground hydrogen storage, but usually there is insufficient information about the formation, and the investment in exploration drilling is high. Depleted oil and gas reservoirs use porous reservoir rocks for hydrogen storage, and their geographical distribution is relatively wide. Hydrogen storage in oil and gas reservoirs can make full use of the accurate reservoir geology and geophysical exploration information obtained, as well as the existing oil and gas wells for hydrogen storage and release operations, which can save a large amount of investment. In shallow underground reservoirs, such as saline aquifers and depleted gas reservoirs, there is potential methanation dominated by microorganisms, which will reduce the purity of the stored hydrogen.

[0005] At present, unconventional oil and gas reservoirs are being developed on a large scale globally, especially tight sandstone, tight sandstone-shale, tight carbonate rock, tight volcanic rock, and mixed tight rock reservoirs with a permeability close to or lower than 0.1 mD. For example, the tight oil and gas basins of Yingtai, Bakken, and Permian in the United States, and the tight gas production areas of Ordos and Sichuan Basins in China. The development of such oil and gas reservoirs mostly requires the combination of horizontal well drilling and multi-stage fracturing technologies, with high input costs. The production decline rate of tight oil and gas reservoirs is fast. After the production drops to the economic lower limit, abandoned wells need to be processed, and the oil and gas wells with huge investments are scrapped. Although carbon dioxide sequestration is one of the options to continue using oil and gas wells, considering that its purpose is long-term geological sequestration rather than recycling, the investment capital in oil and gas drilling and development cannot be fully utilized.

[0006] Geological hydrogen storage has advantages such as low safety risks like hydrogen leakage and explosion, good environmental friendliness, weak influence of surface condition changes on the sealing and stability of the reservoir, strong sustainability, and the ability to store and release hydrogen repeatedly for a long time.

[0007] The Chinese invention patent with the application publication number CN108529124A discloses a method for storing hydrogen on a large scale in underground salt karst cavities. This method uses underground salt caverns to store hydrogen, but the geographical distribution range of salt caverns with good sealing is limited, and the volume of salt caverns is relatively small. The Chinese invention patent with the application publication number CN111439520A discloses an underground oil and gas reservoir hydrogen storage system and a regulation calculation method for hydrogen production from offshore wind power. Although it is also used for hydrogen storage, it is a conventional oil and gas reservoir in the sea with obvious trap structures and is not applicable to land and unconventional oil and gas reservoirs. The Chinese invention patent with the application publication number CN114059083A discloses an underground hydrogen production and storage system and method using solar energy and abandoned oil and gas reservoirs. This method sets the hydrogen production device in the oil and gas reservoir, uses solar energy to generate electricity to electrolyze water to produce hydrogen, then stores the hydrogen in the abandoned oil and gas reservoir, and releases oxygen to the surface. However, the conventional abandoned oil and gas reservoirs it uses have the characteristics of high porosity and high permeability, usually have more injection and production wells, and the uncertainty of the peripheral geological structure is large, with a high risk of hydrogen leakage. The Chinese invention patent with the application publication number CN115573694A discloses a water injection and production system and method for a hydrogen storage reservoir in a saline aquifer. This system and method use an underground saline aquifer as the hydrogen storage space and design an injection well and a production well. The injection well is located at the bottom of the saline aquifer and the production well is located at the top. It requires a large amount of capital, material resources, and manpower to explore the reservoir geological structure information and requires drilling. It can be seen that the existing underground hydrogen storage methods are still difficult to meet the growing development needs of hydrogen energy. Summary of the Invention

[0008] Based on the above technical problems, the present invention proposes a method for storing hydrogen using depleted tight oil and gas reservoirs.

[0009] The technical solution adopted by the present invention is as follows:

[0010] A method for storing hydrogen using depleted tight oil and gas reservoirs, comprising the following steps: using the rock formation of a depleted tight oil and gas reservoir after oil and gas extraction as a hydrogen storage reservoir, continuously injecting hydrogen into the hydrogen storage reservoir through the original horizontal fracturing well during oil and gas extraction, and stopping injecting hydrogen after reaching the expected injection volume;

[0011] When hydrogen is needed, open the horizontal fracturing well to start extracting hydrogen;

[0012] The original horizontal fracturing well includes an original vertical well section and an original horizontal well section. There are fracturing cracks on the original horizontal well section, forming a fracture-controlled volume fracturing reformed area and a non-volume fracturing reformed area. Hydrogen enters the original horizontal well section through the original vertical well section, then enters the fracturing cracks, and undergoes seepage diffusion into the reservoir. The volume fracturing reformed area is the main hydrogen storage area, and the non-volume fracturing reformed area is the oil and gas enrichment area, which can serve as a natural barrier for the sealed hydrogen storage space.

[0013] Preferably, the rock formation of the depleted tight oil and gas reservoir is a depleted tight sandstone oil and gas reservoir or a depleted tight carbonate rock oil and gas reservoir.

[0014] Preferably, keep the working pressure during hydrogen injection and hydrogen extraction at 10 - 70 MPa.

[0015] Preferably, when the bottom hole pressure drops below 5 MPa, it can be judged that the oil and gas are depleted, and stop oil and gas extraction; at this time, switch to injecting and storing hydrogen.

[0016] Preferably, before injecting hydrogen into the hydrogen storage reservoir formed by the rock formation of the depleted tight oil and gas reservoir, inject cushion gas into the horizontal fracturing well first. The cushion gas can fill the void volume of the mined-out area and dissolve into the residual oil phase in small amounts.

[0017] Preferably, after injecting the cushion gas, perform a soaking operation to allow the cushion gas to fully diffuse into the micro-fractures and matrix pores, so that the pressure increase caused by gas injection in the near-well area reaches equilibrium with the formation pressure; at this time, the pressure of the depleted tight oil and gas reservoir is raised to the hydrogen storage and release working pressure level.

[0018] Preferably, the cushion gas is hydrogen, nitrogen or methane.

[0019] Preferably, during the continuous injection of hydrogen, monitor and control the injection pressure in real time to make the bottom hole flowing pressure not higher than the reservoir fracture pressure.

[0020] Preferably, drill a new horizontal well section at the end of the original vertical well section. The new horizontal well section and the original horizontal well section are in different production layer space profiles, forming a horizontal or three-dimensional well pattern, and also perform fracturing reform on the new horizontal well section to form fractures, increasing the scale of hydrogen storage and release.

[0021] Preferably, a new horizontal fracturing well is drilled adjacent to the existing horizontal fracturing well, and the volume fracturing reform areas of the existing horizontal fracturing well and the new horizontal fracturing well overlap. It is expected that the fracturing reform volume in the reservoir can double the hydrogen storage capacity.

[0022] The beneficial technical effects of the present invention are as follows:

[0023] (1) The present invention provides a method for storing and releasing hydrogen using depleted tight oil and gas reservoirs, which can make full use of existing exploration and development information and the wellbore structure of oil and gas wells, realize the reuse of oil and gas investment, and greatly reduce the hydrogen storage cost.

[0024] (2) The present invention uses the rock formation of the depleted tight oil and gas reservoir as a hydrogen storage reservoir. The volume fracturing reform area formed by the horizontal fracturing well in the depleted tight oil and gas reservoir is the main hydrogen storage area, and the non-volume fracturing reform area is the oil and gas enrichment area, which is a natural barrier for the sealed hydrogen storage space; this underground space structure can reduce the risk of hydrogen leakage and maintain a high purity of the produced hydrogen.

[0025] (3) The spatial distribution of the geological strata of tight oil and gas reservoirs is usually larger than the trap structure of conventional oil and gas reservoirs. Selecting a block with better formation integrity for hydrogen storage and release based on geological, geophysical, and development engineering information can ensure high stability.

[0026] (4) Before injecting hydrogen into the depleted tight oil and gas reservoir, a certain volume of cushion gas is first injected into the horizontal fracturing well. The cushion gas can fill the void volume of the mined-out area and dissolve slightly into the residual oil phase, maintaining a high working pressure for hydrogen storage and release, which is beneficial to maintaining a high production rate and purity of the produced hydrogen. The present invention also soaks the well for a period of time after injecting the cushion gas to allow the cushion gas to fully diffuse into the microfractures and matrix pores, so that the pressure increase caused by gas injection in the near-wellbore area is basically balanced with the formation pressure.

[0027] (5) The present invention also drills a new horizontal well section at the end of the original vertical well section. The new horizontal well section and the original horizontal well section are in different vertical formation profiles to increase the scale of hydrogen storage and release. The present invention can also drill a new horizontal fracturing well adjacent to the existing horizontal fracturing well, and the volume fracturing reform areas of the existing horizontal fracturing well and the new horizontal fracturing well overlap, doubling the hydrogen storage capacity of the fracturing reform volume in the reservoir.

[0028] (6) The present invention can supplement the deficiencies of existing ground and underground hydrogen storage technologies and can effectively promote the development of the hydrogen industry chain. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] Figure 1 It is a schematic diagram of the principle of the formation profile of the hydrogen storage reservoir in the depleted tight sandstone gas reservoir;

[0030] Figure 2Schematic diagram of the principle of the formation profile of the hydrogen storage reservoir in depleted carbonate rock reservoirs;

[0031] Figure 3 Schematic diagram of the formation profile for hydrogen storage in a newly added branched well group in a depleted tight oil and gas reservoir;

[0032] Figure 4 Schematic diagram of the profile for hydrogen storage using two adjacent horizontal fractured wells in a depleted tight oil and gas reservoir.

[0033] Figure 1 In the figure: 1 is a horizontal well, 2 is a fracturing crack, 3 is the volume fracturing reformed area - hydrogen enrichment area, 4 is the non - volume fracturing reformed area - methane enrichment area, and 5 indicates the diffusion of hydrogen and the intrusion of methane;

[0034] Figure 2 In the figure: 1 is a horizontal well, 2 is a fracturing crack, 3 is the volume fracturing reformed area - hydrogen enrichment area, 4 is the non - volume fracturing reformed area - residual oil enrichment area, and 5 indicates the diffusion of hydrogen and the intrusion of residual oil;

[0035] Figure 3 In the figure: 1 is a multi - branched well of a horizontal well group, 2 is a fracturing crack, 3 is the volume fracturing reformed area - hydrogen enrichment area, 4 is the non - volume fracturing reformed area - residual oil and gas enrichment area, and 5 indicates the diffusion of hydrogen and the intrusion of residual oil and gas. Detailed implementation method

[0036] Among the existing underground hydrogen storage methods, hydrogen storage in salt caverns is greatly restricted by geographical distribution, the exploration and engineering costs of hydrogen storage in saline aquifers are relatively high, the scale of hydrogen storage in mines is small and the investment is high. Hydrogen storage and release in depleted oil and gas reservoirs mainly utilize depleted conventional oil and gas reservoirs, which are loose and porous, with poor sealing and stability. The tight oil and gas reservoirs in unconventional oil and gas reservoirs are relatively more widely distributed geographically than salt caverns, have relatively lower costs than saline aquifers, are larger in scale than mines, and have better sealing and stability than conventional oil and gas reservoirs.

[0037] The present invention discloses a method for hydrogen storage using a depleted tight oil and gas reservoir, which includes the following steps: using the rock formation of a depleted tight oil and gas reservoir after oil and gas production as a hydrogen storage reservoir, continuously injecting hydrogen into the hydrogen storage reservoir through the original horizontal fractured wells during oil and gas production. After reaching the expected injection volume, stop injecting hydrogen; when hydrogen is needed, open the horizontal fractured wells to start producing hydrogen; over - fracturing is carried out on the horizontal well section of the original horizontal fractured wells to form a volume fracturing reformed area and a non - volume fracturing reformed area controlled by cracks. Hydrogen enters the fracturing cracks through the horizontal wellbore and seeps and diffuses into the reservoir. The volume fracturing reformed area is the main hydrogen storage area, and the non - volume fracturing reformed area is the oil and gas enrichment area, which can serve as a natural barrier for the sealed hydrogen storage space. The present invention can make full use of the existing exploration and development information and the wellbore structure of oil and gas wells, realize the reuse of oil and gas investment, and greatly reduce the hydrogen storage cost.

[0038] The depleted tight oil and gas reservoirs used for hydrogen storage proposed by the present invention have the characteristics of large spatial distribution and ultra-low permeability of the tight oil and gas reservoirs themselves. During oil and gas production, the diversion capacity and storage capacity of the fracture stimulation volume formed by horizontal well fracturing stimulation are significantly improved, which can meet the engineering requirements of rapid hydrogen storage and release. The cap rock and the surrounding un-stimulated reservoirs with ultra-low permeability can play a good sealing role for the stimulated volume, inhibiting the diffusion of hydrogen to the non-volume fracturing stimulation area and the diffusion of oil and gas hydrocarbons into the fracturing stimulation volume. In addition to using single wells, the present invention can also use multiple horizontal wells, as well as well types with larger reservoir control volumes such as horizontal well groups and multilateral wells to increase the scale of hydrogen storage and release and the injection and production rates to meet the actual needs.

[0039] The following further describes the present invention in conjunction with the accompanying drawings and specific embodiments.

[0040] Embodiment 1

[0041] This embodiment provides a method for hydrogen storage and release in a depleted tight sandstone gas reservoir, as Figure 1 shown. The system involved in the method for hydrogen storage and release in a depleted tight sandstone gas reservoir includes a horizontal well, multiple artificial fracturing fractures, a volume fracturing stimulation area controlled by artificial fractures, and a non-volume fracturing stimulation area underground. The hydrogen concentration in and near the fractures is very high, which is a hydrogen enrichment area. The methane concentration in the tight sandstone matrix in the non-volume fracturing stimulation area far from the fractures is relatively high, which is a methane enrichment area. Methane and hydrogen in the pores of the tight sandstone matrix are mainly in the free state and less in the adsorbed state.

[0042] In this embodiment, the horizontal fracturing well with a depth not exceeding 3000 meters was originally used to produce natural gas from the tight sandstone gas reservoir and is now used to inject and produce hydrogen into the fracturing stimulation volume. After the daily production of the gas reservoir horizontal fracturing well drops to 1000 cubic meters per day (the bottom hole pressure usually drops below 5 MPa), the output income during continuous operation is not sufficient to cover the operation cost. It is considered that the fracturing stimulation volume of the tight sandstone reservoir controlled by this single well and the natural gas around it are basically depleted, facing the end of plugging and abandoning the well. The current development of the hydrogen energy industry requires a large-scale hydrogen storage space. The existing horizontal well can be used to inject and store hydrogen into the fracturing stimulation volume of the tight sandstone reservoir and produce it by opening the well when needed.

[0043] In this embodiment, hydrogen is preferentially stored in the volumetric fracturing reformed area in the depleted tight sandstone gas reservoir. Since the density and molecular weight of hydrogen are very small, and its diffusion coefficient is higher than that of methane, hydrogen will gradually diffuse from the volumetric fracturing reformed area to the non-volumetric fracturing reformed area, forming a binary gas mixture with methane in the pores of the non-volumetric fracturing reformed area. When hydrogen is produced, the hydrogen in the volumetric fracturing reformed area is preferentially produced, and the gas mixture in the non-volumetric fracturing reformed area migrates towards the volumetric fracturing reformed area, and methane invades accordingly. However, due to the very low porosity and permeability of the non-volumetric fracturing reformed area, within a relatively high operating pressure range of the hydrogen storage reservoir, such as 10 MPa to 30 MPa, the migration of methane into the volumetric fracturing reformed area is inhibited, so the produced hydrogen can maintain a relatively high purity. The above process forms a dynamic transmission process of hydrogen injection into the underground tight sandstone reservoir and its production therefrom.

[0044] In this embodiment, increasing the working pressure of the horizontal fracturing well can increase the hydrogen storage capacity in the fracturing reformed volume and inhibit the production of methane during the hydrogen production process. Therefore, the working pressure for hydrogen storage and release in the depleted tight sandstone gas reservoir should be maintained at a reasonably high level, preferably 10 MPa to 30 MPa.

[0045] Example 2

[0046] This embodiment provides a method for hydrogen storage and release in a depleted tight carbonate reservoir as Figure 2 shown, which mainly includes the following steps:

[0047] a. The depleted tight carbonate reservoir is exploited by horizontal well drilling and multi-stage staged fracturing technology. When the oil and gas resources in the reservoir drainage space are exploited to the limit daily production under the current technical and economic conditions, such as 0.5 tons per day, the oil and gas production is stopped. At this time, most of the light oil and gas components in the reservoir reformed volume, that is, the volumetric fracturing reformed area, are produced, and the reservoir pressure drops to a relatively low level, such as 3 MPa; heavier hydrocarbons, such as components above pentane, are the main components of the residual oil.

[0048] b. Inject a certain volume of cushion gas into the horizontal fracturing well. The cushion gas is preferably selected from hydrogen, nitrogen, methane, etc.; the cushion gas can fill the void volume of the mined-out pores and dissolve into the residual oil phase in small amounts.

[0049] c. After the injection of the cushion gas is completed, shut in the well for a period of time to allow the cushion gas to fully diffuse into the microfractures and matrix pores, so that the pressure increase caused by gas injection in the near-wellbore zone reaches a basic balance with the formation pressure. At this time, the pressure of the depleted tight carbonate reservoir is increased to the working pressure level for hydrogen storage and release, such as 10 MPa.

[0050] d. Continuously inject the working gas hydrogen into the tight carbonate reservoir through horizontal fracturing wells. During the injection process, the injection pressure should be monitored and controlled in real time to ensure that the bottom-hole flowing pressure does not exceed the reservoir fracture pressure. After reaching the expected injection volume, stop injecting hydrogen. The heavier residual oil is the wetting phase relative to hydrogen in the matrix pores, and the capillary force can effectively hinder the percolation of hydrogen in the reservoir to the periphery; the cushion gas dissolved in the residual oil, such as hydrogen, can significantly reduce the further dissolution and diffusion of hydrogen.

[0051] e. When hydrogen is needed, open the horizontal fracturing well to start producing hydrogen. A small amount of lighter hydrocarbon gases will be produced along with hydrogen. Given different ways of hydrogen reuse, gas separation technology can be used to separate and purify high-purity hydrogen, or hydrogen containing a small amount of hydrocarbons can be directly burned for power generation.

[0052] f. Repeatedly inject and produce hydrogen in the same horizontal fracturing well to form a method for storing and releasing hydrogen in horizontal fracturing wells in tight carbonate reservoirs.

[0053] Example 3

[0054] Methods for increasing the scale of hydrogen storage and release using multi-branch horizontal fracturing wells or multiple horizontal fracturing wells in depleted tight oil and gas reservoirs are as shown in Figure 3 and Figure 4 respectively.

[0055] In the early stage, the tight oil and gas reservoir exploited oil and gas resources using multi-branch horizontal fracturing wells or multiple horizontal fracturing wells, Figure 3 showing a formation profile structure where a vertical well section branches into two horizontal well sections, Figure 4 showing a formation profile structure of two adjacent horizontal fracturing wells. Similar to Example 1 and Example 2, the horizontal well sections are connected to multiple stages of artificial fracturing fractures, forming an artificial fracture-controlled volume fracturing reconstruction area and the surrounding non-volume fracturing reconstruction area. During the hydrogen storage and release process, the hydrogen concentration in and near the fractures is very high, which is the hydrogen enrichment area, and the concentration of oil and gas hydrocarbons in the dense rock matrix in the non-reconstructed area far from the fractures is relatively high, which is the oil and gas hydrocarbon enrichment area.

[0056] In this embodiment, the horizontal fracturing branch wells and the well groups of multiple wells were originally used to increase the contact area with the tight reservoir to efficiently exploit the oil and gas resources therein, and now they are used to inject and produce hydrogen into the fracturing reconstruction volume. After the daily production of the oil and gas reservoir horizontal fracturing well drops below the technical and economic limit (usually the bottom-hole pressure drops below 5 MPa), the income and operating costs are not sufficient, and it is considered that the remaining recoverable oil and gas in the fracturing reconstruction volume controlled by this well and its surrounding area are very few, facing well plugging and abandonment.

[0057] In this embodiment, hydrogen is preferentially stored in the volumetric fracturing reformed area in the depleted tight oil and gas reservoir. Since the oil and gas well has two horizontal well sections and the volumetric fracturing reformed areas controlled respectively, the volume for storing hydrogen can be greatly increased compared with Embodiment 1 and Embodiment 2. For example, when the horizontal section length, the number of fracturing stages and the reservoir physical properties are similar, the hydrogen storage volume is expected to double. When hydrogen is produced, the gas in the fracturing reformed volumes corresponding to the two horizontal well sections can be produced synchronously, increasing the rate of hydrogen release to meet higher ground use requirements.

[0058] In this embodiment, as Figure 4 , the volumetric fracturing reformed areas of two or even multiple horizontal fracturing wells can overlap with each other. In this case, the fracturing reformed volume in the reservoir doubles the hydrogen storage capacity. During the exploitation process, one or more wells can be used to synchronously produce the hydrogen stored in the connected fracturing reformed volumes, increasing the working scale of hydrogen storage and release in the depleted tight oil and gas reservoir.

[0059] The present invention uses specific examples to elaborate on the principle and implementation mode of the method for storing and releasing hydrogen using depleted tight oil and gas reservoirs. However, the above embodiments are only used to help understand the method and its core idea of the present invention. At the same time, the idea of the present invention can be changed by those of ordinary skill in the art in terms of specific implementation modes and application scopes. Therefore, the content of this specification should not be regarded as a limitation to the present invention.

Claims

1. A method for storing hydrogen in depleted tight oil and gas reservoirs, characterized in that The following steps are involved: The depleted tight oil and gas reservoir after oil and gas extraction is used as a hydrogen storage reservoir. Hydrogen is continuously injected into the hydrogen storage reservoir through the original horizontal fracturing wells during oil and gas extraction. When the expected injection volume is reached, the hydrogen injection is stopped. When hydrogen is needed, the horizontal fracturing well is opened to start producing hydrogen; The original horizontal fractured well includes an original vertical well section and an original horizontal well section. There are fractures in the original horizontal well section, forming a fracture-controlled volume fracture reformation area and a non-volume fracture reformation area. Hydrogen enters the original horizontal well section through the original vertical well section and then enters the fractures, and then seeps and diffuses into the reservoir. The volume fracture reformation area is the main hydrogen storage area, and the non-volume fracture reformation area is the oil and gas enrichment area, which can serve as a natural barrier to seal the hydrogen storage space. The depleted tight oil and gas reservoir rock layer is used as a hydrogen storage reservoir. Before injecting hydrogen, cushion gas is first injected into the horizontal fracturing well. The cushion gas can fill the void volume and dissolve a small amount into the residual oil phase. After the injection of cushion gas is completed, the well is soaked to allow the cushion gas to fully diffuse into the microcracks and matrix pores, so that the pressure increase caused by gas injection in the near-wellbore area is balanced with the formation pressure; at this time, the pressure of the depleted tight oil and gas reservoir is raised to the hydrogen storage and release working pressure level.

2. The method for storing hydrogen using depleted tight oil and gas reservoirs according to claim 1, wherein: The depleted tight oil and gas reservoir rock formation is a depleted tight sandstone oil and gas reservoir or a depleted tight carbonate oil and gas reservoir.

3. The method for storing hydrogen using depleted tight oil and gas reservoirs according to claim 1, wherein: The working pressure during hydrogen injection and production is maintained at 10-70 MPa.

4. The method for storing hydrogen using depleted tight oil and gas reservoirs according to claim 1, wherein: When the bottom hole pressure drops below 5MPa, it can be determined that the oil and gas are exhausted and oil and gas production is stopped; at this time, it is switched to injecting and storing hydrogen.

5. The method for storing hydrogen using depleted tight oil and gas reservoirs according to claim 1, wherein: The cushion gas is hydrogen, nitrogen or methane.

6. The method for storing hydrogen using depleted tight oil and gas reservoirs according to claim 1, characterized in that: During the continuous injection of hydrogen, the injection pressure is monitored and controlled in real time to ensure that the bottom hole flow pressure does not exceed the reservoir fracture pressure.

7. The method for storing hydrogen using depleted tight oil and gas reservoirs according to claim 1, characterized in that: A new horizontal well section is drilled at the end of the original vertical well section. The new horizontal well section and the original horizontal well section are in a different pay zone spatial profile, forming a horizontal or three-dimensional well network. Fracturing transformation is also carried out on the new horizontal well section to form cracks, thereby increasing the scale of hydrogen storage and release.

8. The method for storing hydrogen using depleted tight oil and gas reservoirs according to claim 1, characterized in that: A new horizontal fracturing well is drilled adjacent to the original horizontal fracturing well, and the volume fracturing transformation areas of the original horizontal fracturing well and the new horizontal fracturing well are cross-overlapped, so that the fracturing transformation volume in the reservoir increases the hydrogen storage capacity exponentially.

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