Salt cavern gas injection and brine displacement stabilization method and device based on gas-liquid interface regulation

Abstract

This invention provides a method and apparatus for stabilizing brine drainage in salt caverns based on gas-liquid interface control. The method includes: collecting real-time operational monitoring parameters of the salt cavern; determining the gas-liquid interface depth, vertical movement rate of the gas-liquid interface, and fluctuation amplitude of the gas-liquid interface based on the real-time operational monitoring parameters; employing a first control strategy when any one of the following conditions is met: the vertical movement rate of the gas-liquid interface is greater than a first threshold, the fluctuation amplitude of the gas-liquid interface is greater than a second threshold, the rate of change of conductivity is greater than a third threshold, the rate of change of capacitance is greater than a fourth threshold, and the rate of change of pressure at the bottom of the salt cavern is greater than a fifth threshold; employing a second control strategy when the distance between the gas-liquid interface and the brine drainage pipe inlet is less than a preset distance threshold; and employing a third control strategy when the gas-liquid interface reaches the top interface of the salt cavern sediment layer. This invention maximizes brine drainage efficiency and gas storage space utilization through precise and advanced interface control, while ensuring the structural safety of the salt cavern.

Description

Technical Field

[0001] This invention relates to the field of salt cavern energy storage technology, specifically to a method and apparatus for stabilizing salt cavern gas injection and brine discharge based on gas-liquid interface regulation. Background Technology

[0002] Salt cavern gas storage facilities, with their excellent airtightness, structural stability, and high safety, have been widely used in the storage of energy sources such as natural gas and hydrogen, as well as in the construction of compressed air energy storage power plants. Gas injection and brine removal are the core processes in the construction and operation of salt cavern gas storage facilities. This involves injecting high-pressure gas into the salt cavern cavity to displace the brine and create effective gas storage space. The quality of this operation directly determines the storage capacity, operational safety, and service life of the facility.

[0003] The gas-liquid interface depth is a core control parameter for gas injection and brine removal operations. Its position must be strictly maintained within a safe range, directly affecting the stability of the cavity structure and the efficiency of brine removal. Existing technologies generally rely on indirect parameters such as wellhead pressure and flow rate to invert the gas-liquid interface position, lacking direct monitoring methods for the gas-liquid interface depth within the cavity. This results in shortcomings such as monitoring lag, low accuracy, and difficulty in early identification of instability signs. When the gas-liquid interface experiences coneing and instability, shifting below the safe depth, the wellhead parameters may not yet show abnormalities. By the time the abnormal signals are fed back to the surface, it can easily trigger gas channeling and sediment intrusion into the brine removal pipe, leading to safety accidents such as high-pressure gas leakage, brine removal pipeline blockage, and damage to downhole equipment. At the same time, it results in incomplete brine displacement and low utilization of effective gas storage space.

[0004] Therefore, there is an urgent need for a method and apparatus for stabilizing brine in salt caverns by gas injection and desalination based on gas-liquid interface regulation, in order to overcome the shortcomings of existing technologies. Summary of the Invention

[0005] The purpose of this invention is to provide a method and apparatus for stabilizing brine drainage in salt caverns based on gas-liquid interface regulation, so as to solve the technical problems mentioned in the background art.

[0006] To achieve the above objectives, the first aspect of this invention proposes a method for stabilizing salt cavern gas injection and brine discharge based on gas-liquid interface regulation, comprising: Gas is injected into the salt cavern through the gas injection pipe of the gas injection well, and brine is discharged through the brine discharge pipe of the brine discharge well. Real-time operating monitoring parameters of the salt cavern are collected. The real-time operating monitoring parameters include temperature data and acoustic data of the salt cavern wellbore and cavity, pressure change rate at the bottom of the salt cavern, gas injection flow rate change rate, brine discharge flow rate change rate, and electrical data of the brine discharge pipe inlet. The electrical data includes conductivity change rate and capacitance change rate. The gas-liquid interface depth is determined based on temperature data, acoustic data, and electrical data. The vertical migration rate and fluctuation amplitude of the gas-liquid interface are then determined based on the gas-liquid interface depth. The first control strategy is adopted when any one of the following conditions is met: the vertical movement rate of the gas-liquid interface is greater than the first threshold, the fluctuation amplitude of the gas-liquid interface is greater than the second threshold, the rate of change of conductivity is greater than the third threshold, the rate of change of capacitance is greater than the fourth threshold, and the rate of change of pressure at the bottom of the salt cavern is greater than the fifth threshold. When the distance between the gas-liquid interface and the brine discharge pipe inlet is less than a preset distance threshold, the second control strategy is adopted. When the gas-liquid interface reaches the top interface of the salt cavern sediment layer, the third control strategy is adopted.

[0007] Furthermore, the expression for the gas-liquid interface depth is: in, The depth of the gas-liquid interface. Temperature recognition depth; To identify depth using sound waves, For electrical identification depth, , and These are the weighting coefficients. + + =1.

[0008] Furthermore, the first regulatory strategy includes: Reduce the gas injection rate and dynamically adjust the opening of the brine discharge valve to maintain the ratio of the gas injection flow rate change rate to the brine discharge flow rate change rate within a preset range.

[0009] Furthermore, the second regulatory strategy includes: Reduce the gas injection rate and close the brine discharge valve. Adjust the vertical position of the brine discharge pipe inlet until the gas-liquid interface is greater than or equal to the preset distance threshold from the brine discharge pipe inlet. When the fluctuation amplitude of the gas-liquid interface is less than the second threshold, normal gas injection and brine discharge are resumed.

[0010] Furthermore, the third regulatory strategy includes: Reduce the gas injection rate and inject pre-filled liquid into the sediment layer to fill the sediment gaps and displace the residual brine; After the pre-fluid injection is completed, the injection medium is switched to a mixture of nitrogen and tracer gas and the gas injection rate is restored. The concentration of tracer gas at the outlet of the brine drain pipe is monitored in real time. If an increase in the concentration of tracer gas is detected, the gas injection rate is reduced again until the brine drain efficiency stabilizes.

[0011] Furthermore, the tracer gas is at least one of helium, argon, sulfur hexafluoride, or krypton.

[0012] Furthermore, the formula for calculating the brine removal efficiency is: in, To improve brine removal efficiency, The initial brine volume for the target area. This represents the volume of residual brine after the displacement process.

[0013] Furthermore, it also includes: When the brine discharge rate exceeds the preset brine discharge threshold, a stabilizer is injected into the brine discharge pipe inlet to reduce the surface tension of the gas-liquid interface.

[0014] The second aspect of this invention proposes a salt cavern gas injection and brine discharge stabilization device based on gas-liquid interface regulation, comprising a gas injection well, a brine discharge well, and a control center; The control center is used to calculate the gas-liquid interface depth, the vertical movement rate of the gas-liquid interface, and the fluctuation amplitude of the gas-liquid interface based on real-time operation monitoring parameters; the control center is also used to adjust the opening degree of the gas injection valve and the brine discharge valve. Distributed sensor optical fibers are installed on the inner wall of the gas injection pipe of the gas injection well and the outer wall of the brine discharge pipe of the brine discharge well. The distributed sensor optical fibers are used to collect temperature data and acoustic data of the salt cavern well shaft and cavity, the pressure change rate at the bottom of the salt cavern well, the gas injection flow rate change rate, and the brine discharge flow rate change rate. The brine discharge well adopts a double-layer pipe structure, with the outer layer serving as a brine intake channel and the inner layer serving as a gas or light liquid injection channel. The brine discharge well is equipped with a floating suction port assembly, which is used to adjust the vertical position of the brine discharge pipe intake port. A conductivity / capacitance detection probe is installed at the brine discharge pipe intake port to collect the rate of change of conductivity and the rate of change of capacitance.

[0015] A third aspect of the present invention provides a computer-readable storage medium storing a computer program that is executed by a processor to implement the method.

[0016] The beneficial effects of this invention include: Firstly, by using multi-parameter fusion to accurately identify the gas-liquid interface state, this invention can proactively detect signs of interface instability and implement tiered control strategies, effectively preventing safety accidents such as gas channeling, sediment intrusion into the brine discharge pipe, high-pressure gas leakage, and pipeline blockage, thus ensuring the structural safety of the salt cavern. Secondly, by employing weighted calculation of interface depth using multi-source data (temperature, sound, and electrical), the accuracy and real-time performance of interface monitoring are significantly improved, overcoming the shortcomings of traditional indirect parameter inversion, such as lag and large errors. Thirdly, tiered control can dynamically match brine injection and discharge conditions, balancing injection and discharge flow rates when the interface is abnormal, adjusting the suction port position when the interface is near the suction port, and displacing residual brine when the interface reaches the sediment layer, maximizing brine discharge efficiency and gas storage space utilization, and improving the capacity and service life of the salt cavern storage. Fourthly, when the brine discharge rate exceeds the standard, a stabilizer is injected to reduce interface surface tension and suppress violent interface fluctuations, further ensuring stable and efficient operation of the gas injection and brine discharge process. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of a salt cavern gas injection and brine stabilization device based on gas-liquid interface regulation according to an embodiment of the present invention.

[0018] In the diagram, 1: sediment layer; 2: brine; 3: gas-liquid interface; 4: distributed sensor fiber optic cable; 5: floating suction port assembly; 6: gas injection well; 7: control center; 8: brine discharge well; 9: brine discharge pipe suction port; 10: gas injection valve; 11: brine discharge valve; 12: conductivity / capacitance detection probe. Detailed Implementation

[0019] To enable those skilled in the art to better understand the present invention, the technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0020] Example 1 The first aspect of this invention proposes a method for stabilizing salt caverns through gas injection and brine removal based on gas-liquid interface regulation, the method comprising: Gas is injected into the salt cavern through the gas injection pipe of the gas injection well, and brine is discharged through the brine discharge pipe of the brine discharge well. Real-time operating monitoring parameters of the salt cavern are collected. The real-time operating monitoring parameters include temperature data and acoustic data of the salt cavern wellbore and cavity, pressure change rate at the bottom of the salt cavern, gas injection flow rate change rate, brine discharge flow rate change rate, and electrical data of the brine discharge pipe inlet. The electrical data includes conductivity change rate and capacitance change rate. In this embodiment, distributed sensor optical fibers 4 are fixedly installed axially on the inner channel of the gas injection pipe and the outer wall of the brine discharge pipe. The spacing of the distributed sensor optical fibers 4 is preferably 1-5m, the temperature resolution is not less than 0.1℃, the spatial resolution is preferably 0.5-1m, and the acoustic sampling frequency is preferably 100-1000Hz. The distributed sensor fiber 4 works based on the Raman scattering principle. It identifies the location of the gas-liquid interface 3 by acquiring temperature changes at different depths of the wellbore in real time. Due to the significant difference in heat capacity between the gas and the brine, the temperature change response in the gas region is faster, while the temperature change in the brine region is relatively stable. The gas-liquid interface 3 region forms an obvious temperature gradient zone, which is used to determine the temperature identification depth of the gas-liquid interface. The distributed sensor fiber 4 operates based on the Rayleigh scattering principle and is used to identify signals such as bubble bursting, two-phase flow disturbance, interface fluctuation, and local gas channeling. When the gas-liquid interface 3 is disturbed, an obvious anomalous area of ​​acoustic energy will be generated near the interface, which is used to determine the acoustic recognition depth of the gas-liquid interface.

[0021] Multiple conductivity / capacitance detection probes 12 are evenly arranged around the bottom end of the brine discharge column in a circular direction. The number of probes 12 is preferably 3-8, and the multiple probes 12 are evenly distributed in a circular direction to avoid misjudgment caused by local flow field deviation. When probe 12 comes into contact with brine, the conductivity measured by probe 12 increases significantly due to the high ion concentration of brine. When probe 12 comes into contact with gas, the conductivity drops rapidly to near zero. When probe 12 is in the gas-liquid mixing region, its dielectric constant and conductivity both exhibit periodic fluctuations. The system uses the above signal changes to determine the electrical recognition depth of the gas-liquid interface.

[0022] The operating status parameters of the salt cavern are acquired, and the data refresh frequency is preferably 1-10 seconds / time; all data is uploaded to the control center in real time via industrial Ethernet or wireless communication module.

[0023] The depth of the gas-liquid interface 3 is determined based on temperature data, acoustic data, and electrical data. The vertical movement rate and fluctuation amplitude of the gas-liquid interface 3 are then determined based on the depth of the gas-liquid interface 3. Furthermore, the expression for the depth 3 of the gas-liquid interface is: in, The depth of the gas-liquid interface. Temperature recognition depth; To identify depth using sound waves, For electrical identification depth, , and These are the weighting coefficients. + + =1.

[0024] Specifically, the weighting coefficients range from α∈[0.4,0.7], β∈[0.2,0.4], to γ∈[0.05,0.2]. The temperature recognition method has a baseline weight of 0.5~0.7 because it has continuous spatial coverage, significant gradient features, and low noise level. The acoustic recognition method is sensitive to interface disturbances and has high positioning accuracy but is easily affected by mechanical vibration. The baseline weight is set to 0.2~0.4. The electrical recognition method has a fast response but only covers a local area of ​​the inlet. The baseline weight is set to 0.05~0.2.

[0025] In this embodiment, α=0.6, β=0.3, and γ=0.1 are determined.

[0026] In this embodiment, by continuously calculating the interface movement speed, states such as normal and stable advancement, rapid upward surge, local stagnation, and fluctuating decline can be determined. The formula for calculating the vertical movement speed of the gas-liquid interface 3 is as follows: in, This refers to the velocity of the gas-liquid interface. This represents the current gas-liquid interface depth. This represents the depth of the gas-liquid interface at the next moment. This represents the sampling time interval.

[0027] The formula for calculating the amplitude of gas-liquid interface fluctuations, which may occur in irregular salt caverns, is as follows: in, This represents the amplitude of fluctuations at the gas-liquid interface. This represents the maximum height of the gas-liquid interface. This is the lowest height of the gas-liquid interface 3; This represents the diameter of the salt cavern at position 3 of the current gas-liquid interface.

[0028] The amplitude of gas-liquid interface fluctuations is used to identify problems such as interface conicity, wave oscillation, and local displacement.

[0029] When any one of the following conditions is met: the vertical movement rate of the gas-liquid interface 3 is greater than the first threshold, the fluctuation amplitude of the gas-liquid interface 3 is greater than the second threshold, the rate of change of conductivity is greater than the third threshold, the rate of change of capacitance is greater than the fourth threshold, and the rate of change of pressure at the bottom of the salt cavern is greater than the fifth threshold, the first control strategy is adopted. In this embodiment, the first control strategy is adopted when any of the following conditions are met: The vertical movement rate of the gas-liquid interface 3 is greater than 5 m / h, the fluctuation amplitude of the gas-liquid interface 3 is greater than 10% of the local cavity diameter, the conductivity change rate is ≥20%, the capacitance change rate is ≥15%, and the bottom pressure change rate of the salt cavern is greater than 0.5 MPa / min.

[0030] Furthermore, the first regulatory strategy includes: Reduce the gas injection rate and dynamically adjust the opening of the brine discharge valve 11 to maintain the ratio of the gas injection flow rate change rate to the brine discharge flow rate change rate within a preset range.

[0031] In this embodiment, the reduction in the gas injection rate is preferably 10%-30% of the current gas injection volume; Control center 7 dynamically fine-tunes the opening of brine discharge valve 11. If the bottom hole pressure change rate surges due to local pressure buildup, brine discharge valve 11 will actively and moderately open to release local brine back pressure and prevent the pressure change rate from further deteriorating and triggering a vicious cycle of alternating triggers. If the bottom hole pressure change rate drops sharply due to cavity expansion, the opening of brine discharge valve 11 will be moderately reduced.

[0032] In this embodiment, the ratio of the gas injection flow rate change rate to the brine discharge flow rate change rate is within a preset range: ,in, The rate of change of gas injection flow rate, This represents the rate of change in brine discharge flow rate.

[0033] When the distance between the gas-liquid interface 3 and the brine discharge pipe inlet 9 is less than the preset distance threshold, the second control strategy is adopted. Furthermore, the second regulatory strategy includes: Reduce the gas injection rate and close the brine discharge valve 11. Adjust the vertical position of the brine discharge pipe inlet 9 until the distance between the gas-liquid interface and the brine discharge pipe inlet 9 is greater than or equal to the preset distance threshold. When the fluctuation amplitude of the gas-liquid interface 3 is less than the second threshold, the original gas injection rate is restored to discharge brine.

[0034] In this embodiment, the reduction in the gas injection rate is preferably 10%-30% of the current gas injection volume; The preset distance threshold between the gas-liquid interface 3 and the brine discharge pipe inlet 9 is: the brine discharge pipe inlet 9 is 3m below the gas-liquid interface 3; the vertical position of the brine discharge pipe is adjusted. When the position of the brine discharge pipe inlet 9 is too deep, exceeding the preset distance threshold, the brine discharge pipe inlet is controlled to move upward; when the brine discharge pipe inlet 9 is too shallow, less than the preset distance threshold, the brine discharge pipe inlet is controlled to move downward, so that the distance between the gas-liquid interface and the brine discharge pipe inlet 9 is greater than or equal to 3m. By dynamically adjusting the inlet depth, the optimal brine discharge state is continuously maintained, avoiding the impact of gas intake or sediment disturbance on brine discharge efficiency and operational safety.

[0035] When the gas-liquid interface 3 reaches the top interface of the salt cavern sediment layer 1, the third control strategy is adopted.

[0036] Furthermore, the third regulatory strategy includes: Reduce the gas injection rate and inject pre-filled liquid into the sediment layer to fill the sediment gaps and displace the residual brine; After the pre-fluid injection is completed, the injection medium is switched to a mixture of nitrogen and tracer gas and the gas injection rate is restored. The concentration of tracer gas at the outlet of the brine drain pipe is monitored in real time. If an increase in the concentration of tracer gas is detected, the gas injection rate is reduced again until the brine drain efficiency stabilizes.

[0037] In this embodiment, when the gas-liquid interface 3 reaches the top interface of the sediment layer 1, the gas injection rate is preferably reduced by 20%-60% of the current gas injection volume to weaken the fingering effect of gas along high-permeability channels and reduce the risk of local rapid breakthrough. Pre-fluid is injected into the sediment layer 1. This pre-fluid can enter the low-permeability pore areas not yet affected by gas, filling the pore space, displacing retained brine, and blocking the established dominant gas flow channels, thereby increasing the coverage area of ​​subsequent gas displacement. The injection rate is 1.0 m. 3 The injection pressure is 1.05 times the current cavity pressure. The pre-treatment liquid is preferably fresh water, dilute saline, or low-concentration surfactant liquid. The injection is completed when the amount of pre-treatment liquid injected is 10% of the pore volume of the sediment layer 1.

[0038] The original injection medium is changed from air, natural gas, or the main working gas of the storage facility to a mixture of nitrogen and trace tracer gas, wherein nitrogen is the main gas with a volume fraction of 99.0% and the tracer gas has a volume fraction of 1.0%. Furthermore, the tracer gas is at least one of helium, argon, sulfur hexafluoride, or krypton.

[0039] Furthermore, the formula for calculating the brine removal efficiency is: in, To improve brine removal efficiency, The initial brine volume for the target area. This represents the volume of residual brine after the displacement process.

[0040] In this embodiment, before draining the brine, the initial brine volume is determined by measuring the net brine volume of the cavity using downhole three-dimensional sonar. At the end of the brine discharge phase, the residual brine volume V was measured using a downhole liquid level interface detector. r .

[0041] Furthermore, it also includes: When the brine discharge rate exceeds the preset brine discharge threshold, a stabilizer for reducing the surface tension of the gas-liquid interface 3 is injected into the brine discharge pipe inlet 9.

[0042] In this embodiment, the stabilizer is a surfactant used to reduce the surface tension of the gas-liquid interface 3, preferably a nonionic or amphoteric surfactant, and the surfactant can be selected from one or more of polyoxyethylene ethers, betaines, and alkyl glycosides; preferably, the stabilizer is used in the form of an aqueous solution with a mass fraction of 0.01% to 0.20%.

[0043] When the brine discharge rate exceeds 8 m 3At a rate of 0.25 L / min, a nonionic surfactant aqueous solution with a mass fraction of 0.08% is injected into the brine discharge pipe inlet 9. The longest continuous injection time is 48 h.

[0044] Example 2 The second aspect of this invention proposes a salt cavern gas injection and brine removal stabilization device based on gas-liquid interface regulation, such as... Figure 1 As shown, it includes gas injection well 6, brine discharge well 8, and control center 7; The control center 7 is used to calculate the depth of the gas-liquid interface 3, the vertical movement rate of the gas-liquid interface 3, and the fluctuation amplitude of the gas-liquid interface 3 based on real-time operation monitoring parameters; the control center 7 is also used to adjust the opening degree of the gas injection valve 10 and the brine discharge valve 11. Distributed sensor fiber optics 4 are installed on the inner wall of the gas injection pipe of the gas injection well 6 and the outer wall of the brine discharge pipe of the brine discharge well 8 to collect temperature data and acoustic data of the salt cavern well shaft and cavity, the rate of change of pressure at the bottom of the salt cavern well, the rate of change of gas injection flow rate, and the rate of change of brine discharge flow rate. The brine discharge well 8 adopts a double-layer pipe structure, wherein the outer layer is set as a brine suction channel and the inner layer is set as a gas or light liquid injection channel; the brine discharge well is equipped with a floating suction port assembly 5, which is used to adjust the vertical position of the brine discharge pipe suction port 9; the brine discharge pipe suction port 9 is equipped with a conductivity / capacitance detection probe 12, which is used to collect the conductivity change rate and capacitance change rate.

[0045] Example 3 A third aspect of the present invention provides a computer-readable storage medium storing a computer program that is executed by a processor to implement the method described in Embodiment 1.

[0046] The contents not described in detail in this specification are prior art known to those skilled in the art. Those skilled in the art will understand that embodiments of the present invention can be provided as methods, systems, or computer program products. Therefore, the present invention can take the form of a completely hardware embodiment, a completely software embodiment, or an embodiment combining software and hardware aspects. Furthermore, the present invention can take the form of a computer program product embodied on one or more computer-usable storage media (including but not limited to disk storage, CD-ROM, optical storage, etc.) containing computer-usable program code.

[0047] This invention is described with reference to flowchart illustrations and / or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and / or block diagrams, and combinations of blocks in the flowchart illustrations and / or block diagrams, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, special-purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, generate instructions for implementing the flowchart illustrations and / or block diagrams. Figure 1 One or more processes and / or boxes Figure 1 A device that provides the functions specified in one or more boxes.

[0048] These computer program instructions may also be stored in a computer-readable storage medium that can direct a computer or other programmable data processing device to function in a particular manner, such that the instructions stored in the computer-readable storage medium produce an article of manufacture including instruction means, which are implemented in a process Figure 1 One or more processes and / or boxes Figure 1 The function specified in one or more boxes.

[0049] These computer program instructions may also be loaded onto a computer or other programmable data processing equipment to cause a series of operational steps to be performed on the computer or other programmable equipment to produce a computer-implemented process, thereby providing instructions that execute on the computer or other programmable equipment for implementing the process. Figure 1 One or more processes and / or boxes Figure 1 The steps of the function specified in one or more boxes.

[0050] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and not to limit its scope of protection. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that after reading the present invention, they can still make various changes, modifications or equivalent substitutions to the specific implementation of the invention, but these changes, modifications or equivalent substitutions are all within the scope of protection of the pending claims of the invention.

Claims

1. A method for stabilizing salt caverns through gas injection and brine removal based on gas-liquid interface regulation, characterized in that, include: Gas is injected into the salt cavern through the gas injection pipe of the gas injection well, and brine is discharged through the brine discharge pipe of the brine discharge well. Real-time operating monitoring parameters of the salt cavern are collected. The real-time operating monitoring parameters include temperature data and acoustic data of the salt cavern wellbore and cavity, pressure change rate at the bottom of the salt cavern, gas injection flow rate change rate, brine discharge flow rate change rate, and electrical data of the brine discharge pipe inlet. The electrical data includes conductivity change rate and capacitance change rate. The gas-liquid interface depth is determined based on temperature data, acoustic data, and electrical data. The vertical migration rate and fluctuation amplitude of the gas-liquid interface are then determined based on the gas-liquid interface depth. The first control strategy is adopted when any one of the following conditions is met: the vertical movement rate of the gas-liquid interface is greater than the first threshold, the fluctuation amplitude of the gas-liquid interface is greater than the second threshold, the rate of change of conductivity is greater than the third threshold, the rate of change of capacitance is greater than the fourth threshold, and the rate of change of pressure at the bottom of the salt cavern is greater than the fifth threshold. When the distance between the gas-liquid interface and the brine discharge pipe inlet is less than a preset distance threshold, the second control strategy is adopted. When the gas-liquid interface reaches the top interface of the salt cavern sediment layer, the third control strategy is adopted.

2. The salt cavern gas injection and brine removal stabilization method based on gas-liquid interface regulation according to claim 1, characterized in that, The expression for the gas-liquid interface depth is: in, The depth of the gas-liquid interface. Temperature recognition depth; To identify depth using sound waves, For electrical identification depth, , and These are the weighting coefficients. + + =1.

3. The salt cavern gas injection and brine removal stabilization method based on gas-liquid interface regulation according to claim 1, characterized in that, The first regulatory strategy includes: Reduce the gas injection rate and dynamically adjust the opening of the brine discharge valve to maintain the ratio of the gas injection flow rate change rate to the brine discharge flow rate change rate within a preset range.

4. The salt cavern gas injection and brine removal stabilization method based on gas-liquid interface regulation according to claim 1, characterized in that, The second regulatory strategy includes: Reduce the gas injection rate and close the brine discharge valve. Adjust the vertical position of the brine discharge pipe inlet until the gas-liquid interface is greater than or equal to the preset distance threshold from the brine discharge pipe inlet. When the fluctuation amplitude of the gas-liquid interface is less than the second threshold, normal gas injection and brine discharge are resumed.

5. The salt cavern gas injection and brine removal stabilization method based on gas-liquid interface regulation according to claim 1, characterized in that, The third regulatory strategy includes: Reduce the gas injection rate and inject pre-filled liquid into the sediment layer to fill the sediment gaps and displace the residual brine; After the pre-fluid injection is completed, the injection medium is switched to a mixture of nitrogen and tracer gas and the gas injection rate is restored. The concentration of tracer gas at the outlet of the brine drain pipe is monitored in real time. If an increase in the concentration of tracer gas is detected, the gas injection rate is reduced again until the brine drain efficiency stabilizes.

6. The salt cavern gas injection and brine removal stabilization method based on gas-liquid interface regulation according to claim 5, characterized in that, The tracer gas is at least one of helium, argon, sulfur hexafluoride, or krypton.

7. The salt cavern gas injection and brine removal stabilization method based on gas-liquid interface regulation according to claim 5, characterized in that, The formula for calculating brine removal efficiency is: in, To improve brine removal efficiency, The initial brine volume for the target area. This represents the volume of residual brine after the displacement process.

8. The salt cavern gas injection and brine removal stabilization method based on gas-liquid interface regulation according to claim 1, characterized in that, Also includes: When the brine discharge rate exceeds the preset brine discharge threshold, a stabilizer is injected into the brine discharge pipe inlet to reduce the surface tension of the gas-liquid interface.

9. A salt cavern gas injection and brine stabilization device based on gas-liquid interface regulation, characterized in that, Includes gas injection wells, brine discharge wells, and a control center; The control center is used to calculate the gas-liquid interface depth, the vertical movement rate of the gas-liquid interface, and the fluctuation amplitude of the gas-liquid interface based on real-time operation monitoring parameters; the control center is also used to adjust the opening degree of the gas injection valve and the brine discharge valve. Distributed sensor optical fibers are installed on the inner wall of the gas injection pipe of the gas injection well and the outer wall of the brine discharge pipe of the brine discharge well. The distributed sensor optical fibers are used to collect temperature data and acoustic data of the salt cavern well shaft and cavity, the pressure change rate at the bottom of the salt cavern well, the gas injection flow rate change rate, and the brine discharge flow rate change rate. The brine discharge well adopts a double-layer pipe structure, with the outer layer serving as a brine intake channel and the inner layer serving as a gas or light liquid injection channel. The brine discharge well is equipped with a floating suction port assembly, which is used to adjust the vertical position of the brine discharge pipe intake port. A conductivity / capacitance detection probe is installed at the brine discharge pipe intake port to collect the rate of change of conductivity and the rate of change of capacitance.

10. A computer-readable storage medium, characterized in that: The computer-readable storage medium stores a computer program that is executed by a processor to implement the method of any one of claims 1 to 8.

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