A breathing type injection and production hydrogen storage system and method for depleted gas reservoirs

Abstract

The present invention discloses a breathing type injection and production hydrogen storage system for depleted gas reservoirs, comprising a first injection and production well, a second injection and production well, and an injection well. The bottom end of the first injection and production well is located at the bottom of the gas reservoir and is used for injecting and producing CO2. The second injection and production well is arranged between the injection well and the production well, with the bottom end of the second injection and production well located at the top of the gas reservoir and is used for producing natural gas and injecting produced H2. The injection well extends into the bottom water layer and is used for injecting CO2. The present invention also proposes a breathing type injection and production hydrogen storage method for depleted gas reservoirs, comprising a breathing type injection and production hydrogen storage system setup phase, a natural gas production phase, a hydrogen injection and production phase, and a later hydrogen use phase. The depleted gas reservoir is converted into a hydrogen storage depot, CO2 is first injected into the gas reservoir using the second injection and production well, and after the residual natural gas in the gas reservoir is produced from the second injection and production well, the first and second injection and production wells are controlled to achieve breathing type injection and production of H2 in the gas reservoir, thereby improving the hydrogen recovery rate and providing a new approach for the long-term and safe storage of large quantities of hydrogen.

Description

Technical Field

[0001] The present invention relates to the technical field of hydrogen gas storage, and in particular to a breathing type injection and production hydrogen storage system and method for depleted gas reservoirs. Background Art

[0002] The increasing greenhouse gas emissions from the combustion of fossil fuels in human industrial activities have led to increasingly severe negative impacts of global warming and climate change, making the geological storage of carbon dioxide a hot topic of research in recent years. Furthermore, to better address climate change, it is necessary not only to address greenhouse gases but also to adjust the energy structure and increase the development of new energy sources. As a clean energy source with clean combustion and high calorific value, hydrogen has attracted widespread attention from researchers in the field of new energy worldwide.

[0003] Currently, one of the major factors hindering the development of hydrogen energy is its storage. Containers or other media (such as capacitors and batteries) can only store hydrogen for short periods of time and have limited storage capacity. Conventional hydrogen storage methods (such as cylinders and liquefied hydrogen) are unsuitable for large-scale storage, hindering the efficient use of hydrogen energy.

[0004] Compared to surface hydrogen storage, underground hydrogen storage has the characteristics of long service life, large scale, low cost and high safety. Depleted oil and gas reservoirs are recognized as geological structures suitable for storing hydrogen, with good compaction and source rock integrity. However, in the later stages of depleted gas reservoirs, the reduction in internal pressure makes it difficult to extract the natural gas at the bottom of the depleted gas reservoir, resulting in some natural gas remaining in the depleted gas reservoir, which not only squeezes the hydrogen storage space within the depleted gas reservoir, but also pollutes the purity of the hydrogen stored in the depleted gas reservoir, resulting in low hydrogen recovery rate and reduced storage capacity. Therefore, there is an urgent need to propose an effective injection and production hydrogen storage system and method to address the problem that the hydrogen storage space in depleted gas reservoirs is greatly reduced due to the residual unmined natural gas inside, and the residual gas is easy to contaminate the stored hydrogen. Summary of the Invention

[0005] The present invention aims to solve the above-mentioned problems and provides a breathing type injection and production storage system and method for depleted gas reservoirs. By converting the depleted gas reservoir into a hydrogen storage depot and controlling the injection and production sequence of different well locations, breathing type injection and production of the depleted gas reservoir is achieved. This not only realizes the efficient extraction of residual natural gas in the depleted gas reservoir, but also increases the underground storage space of hydrogen, effectively improving the hydrogen recovery rate, and providing new ideas for the geological storage and utilization of hydrogen.

[0006] To achieve the above object, the present invention adopts the following technical solutions:

[0007] A breathing type injection-production hydrogen storage system for depleted gas reservoirs, comprising a first injection-production well, a second injection-production well and an injection well;

[0008] The first injection-production well extends into the bottom of the gas reservoir, and the bottom end of the first injection-production well is located above the bottom water layer, and is used for producing and injecting carbon dioxide;

[0009] The second injection-production well is arranged between the injection well and the first injection-production well, the second injection-production well extends into the top of the gas reservoir, and the bottom end of the second injection-production well is located below the cap rock, and is used for the production of natural gas and the injection and production of hydrogen;

[0010] The injection well extends into the bottom water layer of the gas reservoir and is used for injecting carbon dioxide.

[0011] Preferably, a gas pressure monitoring device is provided at the bottom end of the second injection-production well for measuring the pressure value in the gas reservoir.

[0012] A breathing type injection and production hydrogen storage method for depleted gas reservoirs, using the above-mentioned breathing type injection and production hydrogen storage system for depleted gas reservoirs, specifically comprises the following steps:

[0013] Step 1, the stage of setting up the breathing type injection and production hydrogen storage system;

[0014] Based on the previous geological exploration data and drilling data, the geological structure parameters and maximum bearing pressure P of the gas reservoir are obtained. max And the pressure P in the gas reservoir after extraction A , determine the locations of the first injection-production well, the second injection-production well and the injection well, and set the first injection-production well, the second injection-production well and the injection well;

[0015] Step 2, natural gas production stage;

[0016] Open the injection well, close the first injection-production well and the second injection-production well, inject carbon dioxide into the gas reservoir through the injection well, squeeze the remaining natural gas at the bottom of the gas reservoir to the top of the gas reservoir, and use the pressure monitoring device set at the bottom of the second injection-production well to monitor the internal pressure of the gas reservoir in real time. When the internal pressure of the gas reservoir reaches 10P A When the injection well is closed;

[0017] After waiting for the natural gas and carbon dioxide in the gas reservoir to separate into layers, the second injection-production well is opened, the injection well and the first injection-production well are closed, and the remaining natural gas in the gas reservoir is produced through the second injection-production well. When the wellhead of the second injection-production well detects that the produced gas does not contain natural gas, the second injection-production well is closed;

[0018] Step 3, hydrogen injection and production stage;

[0019] The hydrogen injection and production phase includes the initial phase, hydrogen production phase and hydrogen storage phase;

[0020] In the initial stage, the second injection-production well is opened, the first injection-production well and the injection well are closed, hydrogen is injected into the gas reservoir through the second injection-production well, and the pressure value inside the gas reservoir is monitored in real time using the pressure monitoring device set at the bottom of the second injection-production well. When the amount of hydrogen injected reaches the preset amount of hydrogen injection or the pressure value inside the gas reservoir reaches the maximum pressure P max When the second injection and production well is closed, wait for the hydrogen and carbon dioxide in the gas reservoir to stratify before entering the hydrogen production stage;

[0021] In the hydrogen production phase, the first injection-production well and the second injection-production well are opened, the injection well is closed, and carbon dioxide is injected into the gas reservoir through the first injection-production well. During the injection process, the pressure value inside the gas reservoir is monitored in real time by a pressure monitoring device provided at the bottom of the second injection-production well. The pressure value inside the gas reservoir is kept constant by adjusting the injection rate of carbon dioxide. The hydrogen stored in the gas reservoir is produced using the second injection-production well according to a preset hydrogen production amount. When the produced hydrogen amount reaches the preset hydrogen production amount, the first injection-production well and the second injection-production well are closed, ending the hydrogen production phase and entering the hydrogen storage phase.

[0022] In the hydrogen storage stage, the first injection and production wells are opened, the injection well is closed, hydrogen is injected into the gas reservoir through the second injection and production well, and carbon dioxide in the gas reservoir is discharged from the first injection and production well. The pressure value inside the gas reservoir is monitored in real time by the pressure monitoring device set at the bottom of the second injection and production well. When the amount of hydrogen injected reaches the preset amount of hydrogen injection or the pressure value inside the gas reservoir reaches the maximum pressure P max When the hydrogen storage phase ends, the first injection-production well and the second injection-production well are closed, and the injection of hydrogen into the gas reservoir is stopped.

[0023] Step 4, later hydrogen use stage;

[0024] After the hydrogen injection and production phase is completed, when hydrogen is needed again, the hydrogen in the gas reservoir is extracted during the hydrogen production phase, and then the hydrogen storage phase is repeated to inject hydrogen into the gas reservoir, thereby realizing the breathing injection and production of hydrogen in the gas reservoir.

[0025] Preferably, the geological structural parameters of the gas reservoir include the top and bottom interface positions of the cap layer, the top and bottom interface positions of the gas reservoir and the top and bottom interface positions of the bottom water layer, and the gas storage space volume of the gas reservoir.

[0026] Preferably, in step 2, the standing time is not less than 30 days.

[0027] Preferably, in step 3, the standing time is not less than 30 days.

[0028] The beneficial technical effects brought about by the present invention are:

[0029] The present invention provides a depleted gas reservoir breathing type hydrogen injection and production storage system and method. By setting a first injection and production well, a second injection and production well and an injection well for injecting and producing the depleted gas reservoir, the depleted gas reservoir is converted into a hydrogen storage reservoir. Based on the density difference between natural gas and carbon dioxide, carbon dioxide is first injected into the depleted gas reservoir to increase the internal pressure of the depleted gas reservoir, and the residual natural gas in the depleted gas reservoir is pushed to the top of the gas reservoir by using carbon dioxide for extraction. Then, hydrogen is injected into the depleted gas reservoir. Based on the density difference between hydrogen and carbon dioxide, the cyclic injection and production of hydrogen and carbon dioxide in the depleted gas reservoir is achieved by controlling the first injection and production well and the second injection and production well, thereby realizing the breathing type injection and production of hydrogen in the underground hydrogen storage reservoir.

[0030] The present invention converts depleted gas reservoirs into hydrogen storage tanks, making full use of the abandoned underground space. In conjunction with the establishment of a depleted gas reservoir breathing injection and production hydrogen storage system, it not only achieves the efficient extraction of residual natural gas in the depleted gas reservoir and avoids the waste of oil and gas resources, but also expands the underground storage space of hydrogen by discharging the residual natural gas in the depleted gas reservoir, providing an effective way for the long-term and safe storage of large quantities of hydrogen. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a schematic diagram of the breathing type injection and production hydrogen storage system for depleted gas reservoirs of the present invention.

[0032] In the figure, 1, the first injection-production well, 2, the second injection-production well, 3, the injection well, 4, the cap rock, 5, the gas reservoir, 6, the bottom water layer. DETAILED DESCRIPTION

[0033] The present invention is further described in detail below with reference to the accompanying drawings and embodiments.

[0034] The present invention proposes a breathing type injection and production hydrogen storage system for depleted gas reservoirs, such as Figure 1 As shown, it includes a first injection-production well, a second injection-production well and an injection well.

[0035] The first injection and production well 1 extends into the bottom of the gas reservoir 5. The bottom end of the first injection and production well 1 is located above the bottom water layer and is used to produce carbon dioxide in the gas reservoir and inject carbon dioxide into the gas reservoir.

[0036] The second injection and production well 2 is arranged between the injection well 3 and the first injection and production well 1. The second injection and production well 2 extends into the top of the gas reservoir 5. The bottom end of the second injection and production well 2 is located below the cap rock 4. It is used for the production of natural gas and the injection and production of hydrogen. The bottom end of the second injection and production well 2 is provided with a gas pressure monitoring device for measuring the pressure value in the gas reservoir.

[0037] The injection well 3 extends into the bottom water layer 6 of the gas reservoir and is used to inject carbon dioxide.

[0038] The present invention also proposes a breathing type injection and production hydrogen storage method for depleted gas reservoirs, which uses the above-mentioned breathing type injection and production hydrogen storage system for depleted gas reservoirs, specifically comprising the following steps:

[0039] Step 1: Setting up the breathing type injection and production hydrogen storage system.

[0040] Based on the previous geological exploration data and drilling data, the geological structure parameters and maximum bearing pressure P of the gas reservoir are obtained. max And the pressure P in the gas reservoir after extraction A , determine the locations of the first injection-production well, the second injection-production well and the injection well, and set the first injection-production well, the second injection-production well and the injection well.

[0041] Among them, the geological structure parameters of the gas reservoir include the top and bottom interface positions of the cap layer, the top and bottom interface positions of the gas reservoir and the top and bottom interface positions of the bottom water layer, and the gas storage space volume of the gas reservoir.

[0042] The calculation formula for the gas storage space volume of a gas reservoir is:

[0043] PV=ZnRT (1)

[0044] Where P is the pressure inside the gas reservoir, in MPa; V is the gas storage space volume of the gas reservoir, in m 3 ; Z is the compressibility factor; n is the amount of gas substance, unit is mol; R is the universal gas constant, unit is J / (mol·K); T is the temperature inside the gas reservoir, unit is K.

[0045] Step 2, the natural gas production stage, specifically includes the first natural gas production stage and the second natural gas production stage.

[0046] In the first stage of natural gas production, the injection well is opened, the first injection-production well and the second injection-production well are closed, and carbon dioxide is injected into the gas reservoir through the injection well. Based on the density difference between carbon dioxide and natural gas, the gas pressure inside the gas reservoir is increased while the residual natural gas at the bottom of the gas reservoir is squeezed to the top of the gas reservoir. The gas pressure monitoring device set at the bottom of the second injection-production well is used to monitor the gas reservoir pressure in real time. When the gas reservoir pressure reaches 10P A When the injection well is closed, the second stage of natural gas extraction begins.

[0047] In the second stage of natural gas production, after standing for at least 30 days until the natural gas and carbon dioxide in the gas reservoir are stratified, the second injection and production well is opened, the injection well and the first injection and production well are closed, and the remaining natural gas in the gas reservoir is produced from the top of the gas reservoir through the second injection and production well. When the wellhead of the second injection and production well detects that the produced gas does not contain natural gas, it means that the remaining natural gas in the gas reservoir has been produced. The second injection and production well is closed and the hydrogen injection and production stage begins.

[0048] Step 3, the hydrogen injection and production stage, which specifically includes the initial stage, the hydrogen production stage and the hydrogen storage stage.

[0049] In the initial stage, the second injection-production well is opened, the first injection-production well and the injection well are closed, hydrogen is injected into the gas reservoir through the second injection-production well, and the pressure value inside the gas reservoir is monitored in real time using the pressure monitoring device set at the bottom of the second injection-production well. When the amount of hydrogen injected reaches the preset amount of hydrogen injection or the pressure value inside the gas reservoir reaches the maximum pressure P max At this time, the second injection and production well is closed and the injection of hydrogen into the gas reservoir is stopped. Based on the density difference between hydrogen and carbon dioxide, the gas reservoir is left to stand for at least 30 days until the hydrogen and carbon dioxide in the gas reservoir are stratified, and then the hydrogen production stage is entered.

[0050] During the hydrogen production phase, the first injection and production wells are opened, the second injection and production wells are closed, and carbon dioxide is injected into the gas reservoir through the first injection and production well. During the injection process, the pressure value inside the gas reservoir is monitored in real time by a pressure monitoring device provided at the bottom of the second injection and production well. The pressure value inside the gas reservoir is kept constant by adjusting the injection rate of carbon dioxide. The hydrogen stored in the gas reservoir is produced from the second injection and production well according to a preset hydrogen production amount. When the produced hydrogen amount reaches the preset hydrogen production amount, the first injection and production wells are closed, ending the hydrogen production phase and entering the hydrogen storage phase.

[0051] In the hydrogen storage stage, the first injection and production wells are opened, the injection well is closed, hydrogen is injected into the gas reservoir through the second injection and production well, and carbon dioxide in the gas reservoir is discharged from the first injection and production well. The pressure value inside the gas reservoir is monitored in real time by the pressure monitoring device set at the bottom of the second injection and production well. When the amount of hydrogen injected reaches the preset amount of hydrogen injection or the pressure value inside the gas reservoir reaches the maximum pressure P max When the hydrogen storage stage is complete, the first injection-production well and the second injection-production well are closed, and the injection of hydrogen into the gas reservoir is stopped, thus ending the hydrogen storage stage.

[0052] Step 4, the later stage of hydrogen use.

[0053] After the hydrogen injection and production stage is completed, when hydrogen is needed again, the hydrogen in the gas reservoir is extracted during the hydrogen production stage, and then the hydrogen storage stage is repeated to inject hydrogen into the gas reservoir. By controlling the injection and production of hydrogen in different well locations, breathing-type injection and production of hydrogen in the gas reservoir is achieved.

[0054] The present invention converts depleted gas reservoirs into hydrogen storage tanks, which not only realizes the reuse of abandoned underground space, but also provides a safe reservoir space for large-scale long-term storage of hydrogen. At the same time, the present invention utilizes the density differentiation of hydrogen, natural gas and carbon dioxide, and coordinates the injection and production of different well locations in the breathing injection and production hydrogen storage system to realize the breathing injection and production of carbon dioxide and hydrogen in the depleted gas reservoir. It not only realizes the efficient production of residual natural gas in the depleted gas reservoir, but also improves the hydrogen recovery rate. The storage efficiency is high and it is economical and safe, providing a new way to ensure the long-term safe storage of hydrogen.

[0055] In the description of the present invention, it should be noted that, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," "connected," and "fixed" should be understood in a broad sense. For example, they may refer to fixed connections, detachable connections, or integral connections; they may refer to mechanical connections or electrical connections; they may refer to direct connections or indirect connections through an intermediate medium; and they may refer to internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on specific circumstances.

[0056] Of course, the above description is not a limitation of the present invention, and the present invention is not limited to the above examples. Changes, modifications, additions or substitutions made by technicians in this technical field within the essential scope of the present invention should also fall within the scope of protection of the present invention.

Claims

1. A breathing type injection and production hydrogen storage method for depleted gas reservoirs, characterized in that: A breathing type injection and production hydrogen storage system for depleted gas reservoirs is used, comprising a first injection and production well, a second injection and production well, and an injection well; the first injection and production well extends into the bottom of the gas reservoir, with the bottom end of the first injection and production well located above the bottom water layer, and is used for producing and injecting carbon dioxide; the second injection and production well is arranged between the injection well and the first injection and production well, extends into the top of the gas reservoir, with the bottom end of the second injection and production well located below the cap rock, and is used for producing natural gas and injecting and producing hydrogen; the injection well extends into the bottom water layer of the gas reservoir, and is used for injecting carbon dioxide; a pressure monitoring device is provided at the bottom end of the second injection and production well, for measuring the pressure value in the gas reservoir; The specific steps include: Step 1, the setting stage of the breathing type injection and production hydrogen storage system; Based on the previous geological exploration data and drilling data, the geological structure parameters and maximum bearing pressure P of the gas reservoir are obtained. max And the pressure P in the gas reservoir after extraction A , determine the locations of the first injection-production well, the second injection-production well and the injection well, and set the first injection-production well, the second injection-production well and the injection well; Step 2, natural gas production stage; Open the injection well, close the first injection-production well and the second injection-production well, inject carbon dioxide into the gas reservoir through the injection well, squeeze the remaining natural gas at the bottom of the gas reservoir to the top of the gas reservoir, and use the pressure monitoring device set at the bottom of the second injection-production well to monitor the internal pressure of the gas reservoir in real time. When the internal pressure of the gas reservoir reaches 10P A When the injection well is closed; After waiting for the natural gas and carbon dioxide in the gas reservoir to separate into layers, the second injection-production well is opened, the injection well and the first injection-production well are closed, and the remaining natural gas in the gas reservoir is produced through the second injection-production well. When the wellhead of the second injection-production well detects that the produced gas does not contain natural gas, the second injection-production well is closed; Step 3, hydrogen injection and production stage; The hydrogen injection and production phase includes the initial phase, hydrogen production phase and hydrogen storage phase; In the initial stage, the second injection-production well is opened, the first injection-production well and the injection well are closed, hydrogen is injected into the gas reservoir through the second injection-production well, and the pressure value inside the gas reservoir is monitored in real time using the pressure monitoring device set at the bottom of the second injection-production well. When the amount of hydrogen injected reaches the preset amount of hydrogen injection or the pressure value inside the gas reservoir reaches the maximum pressure P max When the second injection and production well is closed, wait for the hydrogen and carbon dioxide in the gas reservoir to stratify before entering the hydrogen production stage; In the hydrogen production phase, the first injection-production well and the second injection-production well are opened, the injection well is closed, and carbon dioxide is injected into the gas reservoir through the first injection-production well. During the injection process, the pressure value inside the gas reservoir is monitored in real time by a pressure monitoring device provided at the bottom of the second injection-production well. The pressure value inside the gas reservoir is kept constant by adjusting the injection rate of carbon dioxide. The hydrogen stored in the gas reservoir is produced using the second injection-production well according to a preset hydrogen production amount. When the produced hydrogen amount reaches the preset hydrogen production amount, the first injection-production well and the second injection-production well are closed, ending the hydrogen production phase and entering the hydrogen storage phase. In the hydrogen storage stage, the first injection and production wells are opened, the injection well is closed, hydrogen is injected into the gas reservoir through the second injection and production well, and carbon dioxide in the gas reservoir is discharged from the first injection and production well. The pressure value inside the gas reservoir is monitored in real time by the pressure monitoring device set at the bottom of the second injection and production well. When the amount of hydrogen injected reaches the preset amount of hydrogen injection or the pressure value inside the gas reservoir reaches the maximum pressure P max When the hydrogen storage phase ends, the first injection-production well and the second injection-production well are closed, and the injection of hydrogen into the gas reservoir is stopped. Step 4, later hydrogen use stage; After the hydrogen injection and production phase is completed, when hydrogen is needed again, the hydrogen in the gas reservoir is extracted during the hydrogen production phase, and then the hydrogen storage phase is repeated to inject hydrogen into the gas reservoir, thereby realizing the breathing injection and production of hydrogen in the gas reservoir.

2. The breathing type injection and production hydrogen storage method for depleted gas reservoirs according to claim 1, characterized in that: The geological structural parameters of the gas reservoir include the top and bottom interface positions of the cap layer, the top and bottom interface positions of the gas reservoir and the top and bottom interface positions of the bottom water layer, and the gas storage space volume of the gas reservoir.

3. The breathing type injection and production hydrogen storage method for depleted gas reservoirs according to claim 1, characterized in that: In the step 2, the standing time is not less than 30 days.

4. The breathing type injection and production hydrogen storage method for depleted gas reservoirs according to claim 1, characterized in that: In step 3, the standing time is not less than 30 days.

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