Method for producing and storing hydrogen by using waste oil and gas well

Abstract

The invention provides a method for producing and storing hydrogen by using a waste oil-gas well. The method comprises the following steps: selecting a part of the waste oil-gas well as a hydrogen production block; an electrolysis device is arranged in a casing pipe of a hydrogen production block production layer; the anode chamber and the cathode chamber of the electrolysis device are isolated; the other part of the waste oil and gas well is selected as a hydrogen storage bank, and a negative electrode chamber of the electrolysis device is correspondingly communicated with the hydrogen storage bank through a first transmission pipeline; the electrolysis device electrolyzes water, and hydrogen generated by the negative electrode chamber enters the hydrogen storage bank through the first transmission pipeline and penetrates through the perforation of the production layer casing pipe of the hydrogen storage bank to be stored in a stratum reservoir. According to the scheme, the waste oil and gas well is recycled, hydrogen production and hydrogen storage are conducted by means of the characteristics of the oil and gas well, the hydrogen production efficiency can be improved, and cost consumption is reduced to a certain degree.

Description

Technical Field

[0001] The present application relates to the field of hydrogen production, and in particular to a method for producing and storing hydrogen using abandoned oil and gas wells. Background Art

[0002] With the increasing demand for clean energy and the urgency of addressing climate change, hydrogen has garnered widespread attention as a highly promising energy carrier. Currently, gray hydrogen, blue hydrogen, and green hydrogen constitute the mainstream hydrogen production technologies. Green hydrogen, which utilizes electricity generated by renewable energy sources (such as solar and wind power) to electrolyze water into hydrogen and oxygen, is more environmentally friendly than gray and blue hydrogen and represents a truly zero-carbon emission hydrogen production method.

[0003] Currently, the most mature green hydrogen production technology is alkaline electrolysis. Using alkaline electrolytes, it offers advantages such as low cost and mature technology, but it consumes a lot of energy. Therefore, the high production cost of green hydrogen limits its large-scale application. Summary of the Invention

[0004] In order to address the deficiencies of the above-mentioned prior art, the present application provides a method for producing and storing hydrogen using abandoned oil and gas wells, which reuses the abandoned oil and gas wells and utilizes the inherent characteristics of the oil and gas wells to produce and store hydrogen, thereby improving hydrogen production efficiency and reducing cost consumption to a certain extent.

[0005] In order to achieve the above object, the present invention adopts the following technologies: A method for producing and storing hydrogen using abandoned oil and gas wells comprises the following steps: Select a portion of abandoned oil and gas wells as hydrogen production blocks; Install an electrolysis device in the producing layer casing of the hydrogen production block; Isolating the positive and negative electrode compartments of the electrolysis device; Select another portion of abandoned oil and gas wells as hydrogen storage reservoirs, and connect the cathode chambers of the electrolysis device and the hydrogen storage reservoirs correspondingly through a first transmission pipeline; The electrolysis device electrolyzes water, and the hydrogen produced in the negative electrode chamber enters the hydrogen storage reservoir through the first transmission pipeline, and passes through the perforations of the hydrogen storage reservoir production layer casing to be stored in the formation reservoir.

[0006] The beneficial effects of the present invention are: 1. Utilizing the characteristics of abandoned oil and gas wells to produce hydrogen can improve hydrogen production efficiency, reduce power consumption, reduce additional equipment investment, and provide a stable reaction environment for hydrogen production. Utilizing the characteristics of abandoned oil and gas wells to store hydrogen can, to a certain extent, increase hydrogen storage capacity and ensure the safety and stability of hydrogen storage. 2. Reusing abandoned oil and gas wells to achieve integrated hydrogen production and storage can reduce the processing costs of backfilling abandoned wells and reduce the investment in hydrogen production and storage equipment. In practical applications, it can reduce the storage and transportation costs of hydrogen, realize the closed loop of "hydrogen production-hydrogen storage-industrial hydrogen use", and have a certain regional synergy effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] The drawings described herein are for illustrative purposes only of selected embodiments and not all possible implementations, and are not intended to limit the scope of the present invention.

[0008] Figure 1 This is a schematic diagram of the connection between the hydrogen production block and the hydrogen storage tank in the embodiment of the present application.

[0009] Figure 2 It is a structural diagram of the hydrogen production block in the embodiment of the present application.

[0010] Figure 3 It is a cross-sectional schematic diagram of the hydrogen production component in the embodiment of the present application.

[0011] Figure 4 It is a structural diagram of the hydrogen storage tank in the embodiment of the present application. DETAILED DESCRIPTION

[0012] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the embodiments of the present invention are described in detail below with reference to the accompanying drawings. However, the embodiments described in the present invention are only part of the embodiments of the present invention, rather than all the embodiments.

[0013] The present invention provides a method for producing and storing hydrogen using abandoned oil and gas wells. Figure 2 and Figure 4 As shown in FIG, the abandoned oil and gas wells used include surface casing, technical layer casing and production layer casing arranged in sequence from the outside to the inside. The production layer casing is provided with perforations, which are used to connect the inside of the production layer casing with the inside of the formation, as shown in FIG. Figure 1 As shown, the method includes the following steps: selecting a part of abandoned oil and gas wells as hydrogen production blocks; installing an electrolysis device in the production layer casing of the hydrogen production block; using a diaphragm to isolate the positive electrode chamber and the negative electrode chamber of the electrolysis device; selecting another part of abandoned oil and gas wells as hydrogen storage reservoirs, and correspondingly connecting the negative electrode chamber of the electrolysis device to the hydrogen storage reservoir through a first transmission pipeline, and the specific corresponding relationship can be one hydrogen production block corresponding to multiple hydrogen storage reservoirs, or multiple hydrogen storage blocks corresponding to one hydrogen storage reservoir; supplying power to the electrolysis device, the electrolysis device electrolyzes formation water, the positive electrode chamber produces oxygen, and the negative electrode chamber produces hydrogen, wherein the hydrogen produced in the negative electrode chamber enters the hydrogen storage reservoir through the first transmission pipeline, and passes through the perforations of the production layer casing of the hydrogen storage reservoir to be stored in the formation reservoir, and in the process of injecting hydrogen into the formation reservoir, the hydrogen needs to be pressurized.

[0014] The abandoned oil and gas well described in the present application specifically refers to an oil and gas well whose well structure remains complete but has been depleted or exploited to a certain extent. Such oil and gas well is a major environmental hidden danger left by energy development, which is abandoned due to the loss of economic value and will cause a series of problems such as greenhouse gas emission, soil and geological pollution, and surface subsidence if not properly handled. In order to save the backfill cost of the abandoned well and improve the utilization rate of the exploited well, reusing the abandoned oil and gas well to realize the integration of hydrogen production and hydrogen storage is a way out. The characteristics of such oil and gas well itself not only provide sufficient space and favorable conditions for hydrogen production and hydrogen storage, but also reduce the investment cost of hydrogen production equipment and the storage and transportation cost of hydrogen.

[0015] The abandoned oil and gas well is selected as the hydrogen production block, aiming to utilize the natural high temperature and high pressure conditions in the oil and gas well to produce hydrogen without artificially setting up high temperature and high pressure conditions, thereby reducing the additional equipment investment. Secondly, under high temperature and high pressure conditions, water electrolysis for hydrogen production has the advantages of reduced power consumption, increased reaction rate, and being conducive to subsequent hydrogen storage. Specifically, under high temperature and high pressure conditions, the activity of water molecules is enhanced, and the chemical bond is more easily broken, reducing the energy consumption required for water electrolysis. Moreover, the ionic conductivity of water is improved, and the ion migration speed is greatly increased, the reaction rate is accelerated, and the hydrogen production rate is also accelerated, which means that the hydrogen production per unit area or unit volume of electrode is increased, which is conducive to reducing the equipment size. The hydrogen produced under high pressure does not need to be compressed by additional equipment, saving the subsequent compression energy consumption and equipment investment. The stable high temperature environment provided by the oil and gas well can reduce the adverse effects of temperature fluctuations on the reaction, ensuring the stability and continuity of the reaction.

[0016] In addition, deep well high temperature and high pressure hydrogen production has good coupling synergy with renewable energy. Wind and solar power has the characteristics of intermittency and volatility, while deep well hydrogen production can utilize the excess electricity to produce hydrogen when wind and solar power generation is surplus, converting electricity into hydrogen energy for storage. This not only solves the problem of renewable energy consumption, but also realizes efficient use of energy.

[0017] The abandoned oil and gas well is selected as the hydrogen storage library, aiming to utilize the depleted oil and gas well formation reservoir to store hydrogen. Especially for areas with more gas wells, the formation reservoir of gas wells is mainly of fracture and fracture-pore type. When natural gas is depleted, these fractures and fracture-pores can be reused for hydrogen storage.

[0018] This type of oil and gas well has the core advantages of good sealing and low cost. On the one hand, the cap rock of oil and gas wells usually has good pressure bearing capacity and can withstand pressures of tens of megapascals, which makes hydrogen less likely to leak during storage, ensuring the safety and stability of hydrogen storage; on the other hand, hydrogen storage in abandoned oil and gas wells can reuse existing oil and gas facilities, such as wellhead equipment and pipeline systems. The reuse of these facilities can significantly reduce the construction cost and time of the hydrogen storage system. Compared with the construction of new dedicated hydrogen storage facilities, hydrogen storage in abandoned oil and gas wells can save a lot of money and resources. The advantages of using abandoned oil and gas wells to store hydrogen are also reflected in large volume and wide geographical distribution. This large-capacity hydrogen storage capacity enables it to meet energy storage needs of different scales, and can play an important role in both industrial-level energy reserves and regional energy regulation.

[0019] The advantage of reusing abandoned oil and gas wells to achieve integrated hydrogen production and storage also lies in geographical compatibility. Abandoned oil and gas wells, renewable energy hydrogen production projects, and industrial hydrogen companies are relatively close in geographical space. Abandoned oil and gas wells can provide suitable geological conditions for deep-well, high-temperature, and high-pressure hydrogen production and storage, while renewable energy provides sufficient electricity for hydrogen production. This geographical compatibility is particularly significant in Northwest and North China, enabling the establishment of a closed loop of "hydrogen production-hydrogen storage-industrial hydrogen use" in these regions. In this closed loop, renewable energy hydrogen production projects use local clean energy such as wind and solar energy to electrolyze water to produce hydrogen. The produced hydrogen can be directly stored in nearby abandoned oil and gas wells. When industrial hydrogen companies have demand, hydrogen is extracted from abandoned oil and gas wells for use. This regional synergy not only reduces the transportation distance and cost of hydrogen, improves energy utilization efficiency, but also promotes the green development and economic growth of the local energy industry.

[0020] The selection criteria for the hydrogen production block and hydrogen storage reservoir are independent of the well type. Whether the well is horizontal, vertical, or highly deviated, as long as the well structure remains intact, it can be used for hydrogen production and storage. In the examples of this application, horizontal wells will be used as the well type for the hydrogen production block, and vertical wells will be used as the well type for the hydrogen storage reservoir for ease of description.

[0021] Specifically, the liquid pressure of the environment where the electrolysis device is located is 30MPa-50MPa, and the temperature is 150°C-180°C.

[0022] Specifically, such as Figure 2 and Figure 3As shown, a hydrogen production assembly is arranged inside the production layer casing of the hydrogen production block along the axis of the wellbore trajectory. The hydrogen production assembly includes a liquid inlet section, the electrolysis device and a gas outlet section which are sequentially connected along the direction from the inside of the well to the outside of the well. In this embodiment, the liquid inlet section and the electrolysis device are both located in the horizontal section of the horizontal well. A plurality of liquid transmission holes are opened on the side wall of the liquid inlet section. Under the action of the pressure difference between the formation and the bottom of the well, formation water can enter the production layer casing through the perforations on the production layer casing of the hydrogen production block, and then enter the hydrogen production assembly through the liquid transmission holes; two one-way valves are arranged between the liquid inlet section and the electrolysis device, and the two one-way valves correspond to the positive electrode chamber and the negative electrode chamber respectively. The gas outlet section includes an oxygen chamber and a hydrogen chamber. The oxygen chamber is connected to the positive electrode chamber, and the hydrogen chamber is used to connect the negative electrode chamber with the first transmission pipeline. The end of the gas outlet section can be set to a height flush with the wellhead to facilitate connection with the first transmission pipeline.

[0023] When the electrolysis work of the electrolysis device starts, the oxygen and hydrogen produced by the electrolysis of water will move toward the ground through the gas outlet section. The pressure at the electrolysis device is always lower than the liquid pressure at the liquid inlet section. Both one-way valves are open, and formation water will continue to move from the liquid inlet section to the electrolysis device; when the pressure at the electrolysis device is higher than the liquid pressure at the liquid inlet section, both one-way valves are closed to prevent hydrogen and oxygen from flowing toward the liquid inlet section and mixing to cause an explosion.

[0024] To ensure that the electrolysis device can operate continuously and stably, the positive and negative electrodes of the electrolysis device must be in simultaneous and sufficient contact with the formation water to prevent current loop interruption, short circuit, or electrode damage, thereby reducing safety hazards. In this embodiment, the positive and negative electrode chambers of the electrolysis device can be placed on the same horizontal plane.

[0025] Among them, the power of the electrolysis device comes from the uphole power supply, which can come from photovoltaic, wind power, nuclear power, etc. The cable used for power transmission extends from the uphole to the underground and is directly connected to the electrolysis device.

[0026] Specifically, such as Figure 4 As shown in the figure, a packer is installed above the perforation in the casing of the hydrogen storage reservoir's pay zone. The packer is used to prevent hydrogen from migrating to the surface during the hydrogen storage process, thereby improving hydrogen storage stability.

[0027] Preferably, Figure 4 As shown, a rock barrier is installed outside the hydrogen storage reservoir's production layer casing, located above the packer, to prevent hydrogen from leaking to the surface through the annulus. The annulus refers to the gap between adjacent casings or between the casing and the rock formation. Therefore, the rock barrier is primarily installed between the production layer casing and the technical layer casing, and between the production layer casing and the rock formation. The rock barrier primarily utilizes localized high pressure to cause plastic deformation of the casing, squeezing the cement and rock formation, shrinking microcracks and preventing hydrogen molecules from passing through, thereby isolating the hydrogen within the production layer casing.

[0028] Specifically, the cathode chamber of the electrolysis device is connected to a second transmission pipeline, and the second transmission pipeline is used to supply oxygen to the oxygen storage device for industrial use.

[0029] In application, the above description is only a preferred embodiment of the present application and is not intended to limit the present application. Obviously, those skilled in the art can make various changes and modifications to the present application without departing from the spirit and scope of the present application.

Claims

1. A method for producing and storing hydrogen using abandoned oil and gas wells, characterized in that: Including steps: Select a portion of abandoned oil and gas wells as hydrogen production blocks; Install an electrolysis device in the producing layer casing of the hydrogen production block; Isolating the positive and negative electrode compartments of the electrolysis device; Select another portion of abandoned oil and gas wells as hydrogen storage reservoirs, and connect the cathode chambers of the electrolysis device and the hydrogen storage reservoirs correspondingly through a first transmission pipeline; The electrolysis device electrolyzes water, and the hydrogen produced in the negative electrode chamber enters the hydrogen storage reservoir through the first transmission pipeline, and passes through the perforations of the hydrogen storage reservoir production layer casing to be stored in the formation reservoir.

2. The method for producing and storing hydrogen using abandoned oil and gas wells according to claim 1, characterized in that: The liquid column pressure in the environment where the electrolysis device is located is 30MPa-50MPa, and the temperature is 150℃-180℃.

3. The method for producing and storing hydrogen using abandoned oil and gas wells according to claim 1, characterized in that: A hydrogen production assembly is arranged inside the casing of the production layer of the hydrogen production block along the axis of the wellbore trajectory. The hydrogen production assembly includes a liquid inlet section, the electrolysis device and a gas outlet section which are arranged in sequence from the inside of the well to the outside of the well. A plurality of liquid transmission holes are opened on the side wall of the liquid inlet section. Two one-way valves are arranged between the liquid inlet section and the electrolysis device. The two one-way valves correspond to the positive electrode chamber and the negative electrode chamber respectively. The gas outlet section includes an oxygen chamber and a hydrogen chamber. The oxygen chamber is connected to the positive electrode chamber, and the hydrogen chamber is used to connect the negative electrode chamber with the first transmission pipeline.

4. The method for producing and storing hydrogen using abandoned oil and gas wells according to claim 1, characterized in that: A packer is provided above the perforation in the casing of the hydrogen storage reservoir production layer.

5. The method for producing and storing hydrogen using abandoned oil and gas wells according to claim 1, characterized in that: A rock barrier is set on the outside of the casing of the hydrogen storage reservoir production layer to prevent hydrogen from leaking to the ground through the annulus.

6. The method for producing and storing hydrogen using abandoned oil and gas wells according to claim 1, characterized in that: The positive electrode chamber of the electrolysis device is connected to a second transmission pipeline, and the second transmission pipeline is used to supply oxygen to the oxygen storage device.

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