Annular pressure adjusting and monitoring device for salt cavern gas storage of compressed air energy storage power station

Abstract

The utility model relates to the technical field of compressed air energy storage, in particular to an annular pressure adjusting and monitoring device for a salt cavern gas storage of a compressed air energy storage power station. The pressure stabilizing tank body is a closed pressure container, and the interior of the pressure stabilizing tank body is filled with annulus protection liquid and nitrogen; one end of the connecting pipeline is connected with the pressure stabilizing tank body, and the other end is connected with an injection-production well annulus side wing valve; the top of the pressure stabilizing tank is provided with a nitrogen injection channel, and the bottom is provided with an annulus protection liquid injection channel. The negative influence on the fatigue of a packer rubber sleeve at the bottom of the annulus and the anchoring force of a slip due to the periodic dramatic change of the annulus pressure can be relieved, and the annulus can be kept in the state of being soaked in the annulus protection liquid, so that high-pressure oxygen corrosion to a sleeve and an injection-production pipe column after air permeation is avoided.

Description

Technical Field

[0001] This application relates to the field of compressed air energy storage technology, specifically to a device for regulating and monitoring the annular pressure of a salt cavern gas storage tank in a compressed air energy storage power station. Background Technology

[0002] Compressed air energy storage technology is an emerging energy storage technology that utilizes underground caverns formed after the water-soluble mining of underground salt mines as large-scale gas storage devices. During off-peak electricity demand periods, electricity drives an air compressor to compress air into the salt cavern gas storage tank for storage. When the load peaks, the high-pressure air is then delivered to an expander to perform work, converting it into electrical energy for transmission to the power grid. This can play a role in "peak shaving and valley filling," alleviating the grid's peak regulation difficulties. However, in actual engineering operations, because the wellbore is constantly in a state of alternating pressure and temperature, which is further transmitted to the annulus, causing periodic and drastic changes in annulus pressure, it negatively affects the slip anchoring force and sleeve fatigue of the packer at the bottom of the annulus, thus affecting the packer's service life. During annulus depressurization operations in the field, when the four-way side valve of the production tree casing is opened, the annulus comes into contact with air, which can easily lead to air infiltration and subsequent high-pressure oxygen corrosion of the casing and injection / production tubing. Summary of the Invention

[0003] In view of this, the present application provides a device for regulating and monitoring the annular pressure of a compressed air energy storage power station salt cavern gas storage tank. This device can alleviate the negative impact of periodic and drastic changes in annular pressure on the fatigue of the packer sleeve and the anchoring force of the slips at the bottom of the annulus. It can also keep the annulus immersed in the annular protective fluid, thereby preventing high-pressure oxygen corrosion of the casing and injection / production tubing caused by air infiltration.

[0004] This application provides a device for regulating and monitoring the annular pressure of a salt cavern gas storage tank in a compressed air energy storage power station, comprising:

[0005] The pressure stabilizing tank is a closed pressure vessel, filled with annular protective fluid and nitrogen.

[0006] The connecting pipeline is connected to the pressure stabilizing tank at one end and to the annular wing valve of the injection-production well at the other end; the pressure stabilizing tank is equipped with a nitrogen injection channel at the top and an annular protective fluid injection channel at the bottom.

[0007] In one embodiment, a pressure-reducing safety valve is provided on the top of the pressure-stabilizing tank.

[0008] In one embodiment, the bottom of the pressure stabilizing tank also includes a bottom support, the pressure stabilizing tank is disposed on the bottom support, and the bottom height of the pressure stabilizing tank is higher than the height of the annular wing valve of the injection-production well.

[0009] In one embodiment, the pressure-reducing safety valve releases pressure via a mechanical spring structure.

[0010] In one embodiment, a pressure transmitter for detecting the pressure inside the tank is provided on the top of the pressure tank. The data output terminal of the pressure transmitter is connected to the data input terminal of the DCS device, and the control signal output terminal of the DCS device is connected to the control signal input terminal of the pressure reducing safety valve.

[0011] In one embodiment, the side wall of the pressure stabilizing tank is provided with an electronic level gauge for detecting the liquid level of the annular protective fluid inside the pressure stabilizing tank, and the data output terminal of the electronic level gauge is connected to the data input terminal of the DCS device.

[0012] In one embodiment, a gas detection device is installed on the top of the pressure stabilizing tank, and the data output terminal of the gas detection device is connected to the data input terminal of the DCS device.

[0013] In one embodiment, the pressure stabilizing tank is provided with a nitrogen injection valve for nitrogen injection.

[0014] In one embodiment, the pressure stabilizing tank is equipped with a nitrogen recirculation valve for discharging gas from the tank.

[0015] In one embodiment, a sampling device is provided at the nitrogen circulation valve, and the data output terminal of the sampling device is connected to the data input terminal of the DCS device.

[0016] This embodiment of the application incorporates a pressure-stabilizing tank, a sealed pressure vessel filled with annular protective fluid and nitrogen. A connecting pipeline connects one end to the pressure-stabilizing tank and the other end to the annular side valve of the injection / production well. The pressure-stabilizing tank has a nitrogen injection channel at the top and an annular protective fluid injection channel at the bottom. By utilizing the coexistence of nitrogen and annular protective fluid within the tank, the compressibility of nitrogen absorbs annular pressure fluctuations, while the protective fluid is directly connected to the annulus, preventing air infiltration. This achieves a dual effect of dynamic pressure balance and corrosion protection. It mitigates the negative impact of periodic and dramatic annular pressure changes caused by cyclic injection and production in energy storage power plants on the fatigue of the annular bottom packer sleeve and the anchoring force of the slips, and keeps the annulus immersed in the annular protective fluid, preventing high-pressure oxygen corrosion of the casing and injection / production tubing caused by air infiltration. Attached Figure Description

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

[0018] Figure 1 This is a schematic diagram of the structure of a compressed air energy storage power station salt cavern gas storage annular pressure regulation and monitoring device provided in one embodiment of this application;

[0019] Figure 2 This is a schematic diagram showing the connection between the device of this application and the annular wing valve of the injection and production well;

[0020] In the diagram: 100 - Annular pressure regulation and monitoring device for compressed air energy storage power station salt cavern gas storage, 200 - Annular side valve of injection and production well;

[0021] 1-Pressure stabilizing tank, 2-Pressure reducing safety valve, 3-Pressure transmitter, 4-Gas detection device, 5-Nitrogen injection valve, 6-Nitrogen circulation valve, 7-Electronic level gauge, 8-Connecting pipeline, 9-Bottom support. Detailed Implementation

[0022] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0023] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0024] like Figure 1 , 2 As shown in the figure, this application provides a device for regulating and monitoring the annular pressure of a compressed air energy storage power station's salt cavern gas storage tank, comprising:

[0025] The pressure stabilizing tank 1 is a closed pressure vessel, which is filled with annular protective fluid and nitrogen.

[0026] Connecting pipeline 8, one end is connected to pressure stabilizing tank 1, and the other end is used to connect to the annular side valve 200 of injection and production well;

[0027] The pressure stabilizing tank 1 is equipped with a nitrogen injection channel at the top and an annular protective liquid injection channel at the bottom.

[0028] In application, this device connects to the annular side valve of the gas production tree to achieve annular pressure regulation and monitoring. The length of connecting pipeline 8 is determined based on the actual site location, using a rigid pipeline with a pressure rating of 3 MPa. For example, a 3 MPa stainless steel pipe is used to ensure no deformation under high pressure. During injection and production, the annular protective fluid enters the tank through the pipeline; during depressurization, the protective fluid flows back to the annulus through the pipeline. The pipeline length is customized according to the site distance to reduce the impact of fluid resistance on pressure transmission.

[0029] In application, the pressure stabilizing tank 1 is a simple, sealed pressure vessel. As the core pressure buffer container, it stores annular protective fluid and nitrogen, absorbing annular pressure fluctuations through gas compressibility to maintain system pressure stability. Based on the annular pressure conditions of the injection and production wells and the expansion volume of the protective fluid, it is set with a pressure rating of 1 MPa and an internal volume of 500-800 ml, using corrosion-resistant and heat-insulating materials with good airtightness. During initialization, annular protective fluid (such as a glycerol-based liquid) is injected into the lower part of the tank, and nitrogen is injected into the upper part, forming a gas-liquid interface (the liquid level is monitored by an electronic level gauge). Multiple sets of valves are installed internally, connecting to the annular space of the injection and production wells, the nitrogen injection and discharge channels, the protective fluid injection channel, and atmospheric pressure.

[0030] During injection and production, the annular protective fluid expands due to the increase in temperature and enters the tank through the connecting pipeline, compressing the nitrogen volume. When the annular pressure drops, the nitrogen in the tank expands and pushes the protective fluid back into the annulus, achieving dynamic pressure balance.

[0031] This embodiment of the application incorporates a pressure-stabilizing tank, a sealed pressure vessel filled with annular protective fluid and nitrogen. A connecting pipeline connects one end to the pressure-stabilizing tank and the other end to the annular side valve of the injection / production well. The pressure-stabilizing tank has a nitrogen injection channel at the top and an annular protective fluid injection channel at the bottom. By utilizing the coexistence of nitrogen and annular protective fluid within the tank, the compressibility of nitrogen absorbs annular pressure fluctuations, while the protective fluid is directly connected to the annulus, preventing air infiltration. This achieves a dual effect of dynamic pressure balance and corrosion protection. It mitigates the negative impact of periodic and dramatic annular pressure changes caused by cyclic injection and production in energy storage power plants on the fatigue of the annular bottom packer sleeve and the anchoring force of the slips, and keeps the annulus immersed in the annular protective fluid, preventing high-pressure oxygen corrosion of the casing and injection / production tubing caused by air infiltration.

[0032] In one embodiment, a pressure-reducing safety valve 2 is provided on the top of the pressure-stabilizing tank 1.

[0033] In application, pressure reducing safety valve 2 is located at the top of the tank and is set with a safety pressure threshold (e.g., 0.8 MPa). When the tank pressure is higher than the pressure threshold, pressure reducing safety valve 2 opens to release the pressure inside the tank.

[0034] This application embodiment uses a pressure-reducing safety valve to release pressure when the pressure inside the tank rises abnormally, preventing the tank from overloading and rupturing, and ensuring system safety.

[0035] In one embodiment, the bottom of the pressure stabilizing tank 1 further includes a bottom support 9, and the pressure stabilizing tank 1 is mounted on the bottom support 9. The bottom height of the pressure stabilizing tank 1 is higher than the height of the annular side valve of the injection-production well. The specific height of the support is determined based on actual on-site measurements.

[0036] This embodiment of the application avoids the annular protective fluid from flowing into the tank due to the gravitational potential energy difference by making the bottom height of the pressure stabilizing tank higher than the height of the annular side wing valve of the injection and production well.

[0037] In one embodiment, the pressure-reducing safety valve 2 releases pressure via a mechanical spring structure.

[0038] This application embodiment provides an overpressure protection threshold (e.g., 0.8 MPa) through a mechanical safety valve, which automatically releases pressure when the pressure inside the tank abnormally increases, preventing the tank from overloading and rupturing, and ensuring system safety. The mechanical structure does not rely on external power or control signals and can still reliably release pressure under extreme conditions (such as power outages or DCS failures), enhancing system redundancy and safety.

[0039] In one embodiment, the top of the pressure-stabilized tank 1 is provided with a pressure transmitter 3 for detecting the pressure inside the tank. The data output terminal of the pressure transmitter 3 is connected to the data input terminal of the DCS device, and the control signal output terminal of the DCS device is connected to the control signal input terminal of the pressure-reducing safety valve 2.

[0040] In application, pressure transmitter 3 is located at the top of the tank to monitor the pressure inside the tank and provide pressure input to pressure reducing safety valve 2. The model can be consistent with the annulus pressure transmitter in the injection and production wells. It is connected to the well site monitoring system via a DCS line, enabling real-time monitoring, recording, and processing of data remotely.

[0041] This application embodiment transmits pressure data remotely to a DCS system to achieve real-time monitoring and historical data analysis of the tank pressure. When the tank pressure is too high, the DCS system can trigger a pressure-reducing safety valve to release pressure. However, the pressure-reducing safety valve still retains a mechanical autonomous triggering mechanism to avoid over-reliance on electronic control, thus balancing automation and safety redundancy.

[0042] In one embodiment, the side wall of the pressure stabilizing tank 1 is provided with an electronic level gauge 7 for detecting the liquid level of the annular protective fluid inside the pressure stabilizing tank 1, and the data output terminal of the electronic level gauge 7 is connected to the data input terminal of the DCS device.

[0043] In the application, the electronic level gauge 7 is located on the side of the tank and uses ultrasound to detect the liquid level inside the tank. The ultrasonic probe is installed on the side of the tank, emitting sound waves and receiving the reflected signals from the liquid surface, calculating the liquid level based on the time difference. For example, a sudden rise in the liquid level indicates a large influx of annular protective fluid, requiring the activation of the pressure relief valve to release pressure; a continuous drop in the liquid level indicates an annular protective fluid leak, requiring replenishment of fluid.

[0044] This application embodiment monitors the change in the volume of the protective fluid in real time using liquid level data to determine whether the annular protective fluid is leaking or excessively expanding, providing a basis for maintenance decisions and reducing the cost of manual inspection.

[0045] In one embodiment, a gas detection device 4 is installed on the top of the pressure stabilizing tank 1, and the data output terminal of the gas detection device 4 is connected to the data input terminal of the DCS device.

[0046] In the application, gas detection device 4, located at the top of the tank, is used to detect the oxygen concentration inside the tank, thereby determining the airtightness of the injection-production well annulus. If an abnormally high O2 concentration is detected (e.g., >1%), it indicates that the annulus seal has failed, and air has seeped into the system through the casing. This can trigger an alarm, prompting maintenance personnel to check for leaks (such as packer sleeve damage or valve seal failure).

[0047] This application embodiment continuously monitors the oxygen concentration inside the tank. If the concentration rises abnormally, it can provide an early warning of annular air tightness failure, prevent subsequent high-pressure oxygen corrosion, and extend the service life of the casing and injection / production tubing.

[0048] In one embodiment, the pressure stabilizing tank 1 is provided with a nitrogen injection valve 5 for nitrogen injection.

[0049] During the initialization phase, nitrogen gas is injected into the upper part of the tank through this valve until the pressure reaches 0.5MPa. If the tank pressure continues to drop due to the backflow of protective fluid (e.g., <0.2MPa) during operation, the valve can be opened manually / automatically to replenish the gas and restore the pressure to the normal range of 0.3-0.5MPa.

[0050] This application embodiment maintains an inert gas environment inside the tank by conveniently replenishing nitrogen, preventing oxygen from seeping in, and also supports gas loss compensation during long-term system operation.

[0051] In one embodiment, the pressure stabilizing tank 1 is provided with a nitrogen circulation valve 6 for the discharge of gas from the tank.

[0052] In application, nitrogen circulation valve 6, located at the lower 1 / 3 of the tank height, is used for nitrogen circulation and discharge. A sampling device can also be added to collect gas samples. During initialization, this valve is opened to discharge initial nitrogen mixed with air until pure nitrogen flows out, then it is closed. During operation, it is opened periodically in conjunction with the sampling device to detect nitrogen composition (such as detecting whether H2S or CO2 is mixed in), ensuring the gas remains inert.

[0053] This application embodiment ensures nitrogen purity and improves pressure regulation efficiency by periodically venting gas impurities (such as mixed air or corrosive gases) from the tank, and the gas composition can be detected by sampling through valves.

[0054] In one embodiment, a sampling device is provided at the nitrogen circulation valve 6, and the data output terminal of the sampling device is connected to the data input terminal of the DCS device.

[0055] This application embodiment acquires gas composition data (such as H2S and CO2 content) in real time through a sampling device, which can detect potential corrosion risks in advance, assist in the formulation of preventive maintenance plans, and reduce equipment failure rate.

[0056] The method of using this device is as follows:

[0057] 1. The pressure stabilizing tank 1 is connected to the side valve at one end of the injection-production well annulus via the connecting pipeline 8. Annulus protection fluid is injected through the other end of the side valve, so that the annulus protection fluid fills the ground pipeline and the tank.

[0058] 2. Nitrogen is injected into the tank from the top through nitrogen injection valve 5. When the pressure reaches a set value (usually 0.5 MPa), nitrogen circulation valve 6 opens, and the annular protective fluid at the top of the circulation valve flows out until nitrogen is circulated out. Then, nitrogen injection valve 5 is closed. When the pressure inside the tank decreases to a set value (usually 0.2-0.3 MPa), the circulation valve is closed. At this point, the upper part of the tank is filled with nitrogen, and the lower part is filled with annular protective fluid.

[0059] 3. When the injection-production well enters the injection-production operation and the annular pressure rises, the side valve connected to the tank opens. The annular protective fluid expands due to heat and enters the tank. The nitrogen gas inside the tank is compressed. Due to the strong compressibility of gas, the pressure eventually stabilizes below 1.0 MPa. When the annular pressure drops, part of the annular protective fluid falls back into the annulus of the injection-production well, and the tank pressure decreases, eventually maintaining a normal range of 0.3-0.5 MPa. This process achieves the function of regulating the annular pressure of the injection-production well.

[0060] 4. By observing the oxygen concentration through the gas detection device 4 on the top of the tank, it is possible to determine whether external gases such as compressed air have entered the annulus of the injection and production wells, thereby realizing the function of monitoring the air tightness of the injection and production well annulus.

[0061] The above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this application, and should all be included within the protection scope of this application.

Claims

1. A compressed air energy storage power plant salt cavern gas storage reservoir annulus pressure regulating and monitoring device, characterized in that, The utility model relates to a nitrogen pressure stabilizing tank for injection-production well annular protection liquid, comprising: A pressure stabilizing tank (1) is a closed pressure vessel, which is internally filled with annular protection liquid and nitrogen; A connecting pipeline (8) is connected to one end of the pressure stabilizing tank (1) and the other end is used to connect with the annular side valve (200) of the injection-production well; The top of the pressure stabilizing tank (1) is provided with a nitrogen injection channel, and the bottom is provided with an annular protection liquid injection channel.

2. The apparatus of claim 1, wherein, The top of the pressure stabilizing tank (1) is provided with a pressure relief safety valve (2).

3. The apparatus of claim 1, wherein, The bottom of the pressure stabilizing tank (1) further comprises a bottom support (9), the pressure stabilizing tank (1) is arranged on the bottom support (9), and the bottom height of the pressure stabilizing tank (1) is higher than the height of the annular side valve (200) of the injection-production well.

4. The apparatus of claim 2, wherein, The pressure relief safety valve (2) realizes pressure release through a mechanical spring structure.

5. The apparatus of claim 2, wherein, The top of the pressure stabilizing tank (1) is provided with a pressure transmitter (3) for detecting the pressure in the tank, the data output end of the pressure transmitter (3) is connected with the data input end of a DCS device, and the control signal output end of the DCS device is connected with the control signal input end of the pressure relief safety valve (2).

6. The apparatus of claim 1, wherein, The side wall of the pressure stabilizing tank (1) is provided with an electronic liquid level meter (7) for detecting the liquid level height of the annular protection liquid in the pressure stabilizing tank (1), and the data output end of the electronic liquid level meter (7) is connected with the data input end of a DCS device.

7. The apparatus of claim 1, wherein, The top of the pressure stabilizing tank (1) is provided with a gas detection device (4), and the data output end of the gas detection device (4) is connected with the data input end of a DCS device.

8. The apparatus of claim 1, wherein, The pressure stabilizing tank (1) is provided with a nitrogen injection valve (5) for nitrogen injection.

9. The apparatus of claim 1, wherein, The pressure stabilizing tank (1) is provided with a nitrogen circulation valve (6) for discharging gas in the tank.

10. The apparatus of claim 9, wherein, A sampling device is arranged at the nitrogen circulation valve (6), and the data output end of the sampling device is connected with the data input end of a DCS device.

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