Device and method for simulating sediment migration of salt cavern reservoir under multi-factor coupling effect

Abstract

The invention discloses a device and method for simulating sediment migration of a salt cavern reservoir under a multi-factor coupling effect, and the device comprises a salt cavern simulation system which comprises a simulation gas injection cavity and a simulation brine discharge cavity, and the bottoms of the simulation gas injection cavity and the simulation brine discharge cavity are connected through a communication channel; the multi-mode gas injection system is connected with the simulation gas injection cavity, comprises at least two gas sources which can be independently controlled, and can inject gas in sequence or in a mixed manner; the brine circulating system is connected with the simulated brine discharging cavity; the stratigraphic dip angle simulation mechanism is used for fixing the salt cavern simulation system and adjusting the inclination angle; the earthquake simulation vibration table can apply programmable earthquake vibration; the pressure balance compensation system is connected with gas-phase spaces at the tops of the two cavities and automatically compensates gas when the pressure difference exceeds a threshold value; and the particle image velocity measurement system is used for capturing and analyzing sediment migration in the communication channel. Multiple key factors influencing sediment migration are integrated, injection-production operation can be simulated, dimensions such as gas components, geological forms, safety operation and disaster loads are introduced, and the fidelity of a simulation experiment is improved.

Description

Technical Field

[0001] This invention relates to the field of salt cavern storage simulation experiments, specifically to an apparatus and method for simulating the transport of sediment in a salt cavern storage under the coupled effects of multiple factors. Background Technology

[0002] With the ever-increasing demand for energy storage, salt cavern energy storage technology has attracted widespread attention. As a natural underground storage space, salt caverns possess excellent sealing and stability, enabling the safe storage of large quantities of energy. However, salt caverns face various complex situations during long-term operation, among which the migration of insoluble sediment at the bottom of the chamber poses a potential threat to storage safety. Particularly for future hydrogen storage facilities, the mixed use of hydrogen and cushion gas, as well as factors such as the geological environment of the salt mine site, further complicate the sediment migration problem. Therefore, in-depth research into the sediment migration patterns of salt cavern storage is crucial for ensuring storage safety.

[0003] In related technologies, simulation devices are commonly used to study the migration of sediment in salt cavern storage facilities. However, most simulation devices can only simulate simple injection and production processes, such as focusing solely on gas injection and discharge to observe sediment migration under these simple conditions. For conditions such as hydrogen storage, they cannot simulate the initial injection of cushion gas, nor can they simulate the complex gas environment resulting from the mixing of cushion gas and working gas after long-term operation. Furthermore, they generally neglect key geological factors such as formation dip angle, failing to consider their impact on sediment migration. Additionally, they do not consider the severe disturbances to the internal dynamic environment of the storage facility caused by extreme external loads such as earthquakes, and these factors are not included in the simulation scope of the experiments.

[0004] Existing simulation devices have significant limitations. Their operating condition simulations are limited to a single scenario, making it impossible to simulate complex gaseous environments and study the impact of gas composition changes on sediment transport. Furthermore, they lack geological and hazard factors, neglecting key geological elements and extreme external loads, thus failing to comprehensively reflect the actual conditions of salt cavern storage. In addition, existing devices ignore crucial safety operations such as pressure balancing compensation necessary to mitigate negative pressure risks in actual engineering, and cannot study the dynamic impact of these operations on sediment stability. In summary, existing technologies cannot study the cumulative risk effects of simultaneous "worst-case" events such as earthquakes during injection and production operations, resulting in a severe disconnect between experimental results and engineering safety assessment requirements, and failing to provide effective references for the safety design and risk assessment of salt cavern energy storage projects. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and to propose a device and method for simulating the migration of sediment in salt cavern storage under the coupled effects of multiple factors.

[0006] To achieve the above-mentioned technical objectives, the present invention adopts the following technical solution:

[0007] This invention provides an apparatus for simulating the migration of sediment in a salt cavern storage tank under the coupled effects of multiple factors, comprising:

[0008] The salt cavern simulation system includes a simulated gas injection chamber and a simulated brine discharge chamber. The bottom of the simulated gas injection chamber and the bottom of the simulated brine discharge chamber are connected by a connecting channel. The bottom of the gas injection chamber is deposited with sediment particles and fluid tracer particles.

[0009] A multi-mode gas injection system is connected to the simulated gas injection chamber. The multi-mode gas injection system includes at least a first gas source and a second gas source that can be controlled independently, and can supply gas to the simulated gas injection chamber in a sequential injection or mixed injection manner according to a preset ratio.

[0010] A brine circulation system, which is connected to the simulated brine discharge chamber;

[0011] A formation dip angle simulation mechanism is used to fix and install the salt cave simulation system, and to adjust the overall tilt angle of the salt cave simulation system;

[0012] An earthquake simulation shaking table, on which the stratum dip angle simulation mechanism is mounted, is used to apply programmable earthquake simulation vibrations to the entire system;

[0013] A pressure balance compensation system connects the top gas phase space of the simulated gas injection chamber and the top gas phase space of the simulated brine discharge chamber. The pressure balance compensation system is used to automatically perform gas compensation when the pressure difference between the two chambers exceeds a preset threshold.

[0014] A particle image velocimetry system is used to quantitatively capture and analyze the transport process of sediment within the connected channel.

[0015] In some embodiments, the pressure balance compensation system includes a pressure balance pipe, two first pressure detection elements and a control valve. The two ends of the pressure balance pipe are respectively connected to the simulated gas injection chamber and the simulated brine discharge chamber. The two first pressure detection elements are respectively disposed at the two ends of the pressure balance pipe. The control valve is disposed on the pressure balance pipe and located between the two first pressure detection elements.

[0016] In some embodiments, the two gas sources of the multi-mode gas injection system are a cushion gas source and a hydrogen gas source, respectively, to simulate hydrogen storage conditions with different cushion gas ratios.

[0017] In some embodiments, the multi-mode gas injection system further includes a main injection pipe, one end of which is connected to the simulated gas injection chamber, and a second pressure detection element and a flow meter are provided on the main injection pipe;

[0018] The first gas source includes a first gas tank, a first gas outlet pipe and a first gas pump. The first gas tank is used to store a first gas. One end of the first gas outlet pipe is connected to the outlet of the first gas tank. A first gas valve is provided on the first gas outlet pipe. The inlet of the first gas pump is connected to the other end of the first gas outlet pipe. The outlet of the first gas pump is connected to the main injection pipe.

[0019] The second gas source includes a second gas tank, a second gas outlet pipe, and a second gas pump. The second gas tank is used to store a second gas. One end of the second gas outlet pipe is connected to the outlet of the second gas tank. A second gas valve is provided on the second gas outlet pipe. The inlet of the second gas pump is connected to the other end of the second gas outlet pipe. The outlet of the second gas pump is connected to the main injection pipe.

[0020] In some embodiments, the earthquake simulation shaking table can be input with real seismic wave data to reproduce seismic loads of different magnitudes and types.

[0021] In some embodiments, the formation dip angle simulation mechanism includes a fixed plate, a mounting plate, and several adjusting rods of different lengths. The fixed plate is fixed to the earthquake simulation shaking table, and the mounting plate is used to fix the salt cave simulation system. A first hinge block is formed on the fixed plate, and a second hinge block is formed on the mounting plate. The second hinge block is hinged to the first hinge block. One end of the adjusting rod is detachably connected to the first fixed block formed on the fixed plate, and the other end of the adjusting rod is detachably connected to the second fixed block formed on the mounting plate. By selecting adjusting rods of different lengths to connect between the first fixed block and the second fixed block, the dip angle of the mounting plate can be adjusted.

[0022] In some embodiments, the particle image velocimetry system includes a high-frequency laser and a high-speed camera. The high-frequency laser is used to emit sheet light to illuminate the measurement plane within the communicating channel, and the high-speed camera is used to continuously capture images of the illuminated sediment particles and fluid tracer particles within the plane.

[0023] This invention also provides a method for simulating the transport of sediment in a salt cavern storage tank under the coupled effects of multiple factors, applicable to the aforementioned apparatus for simulating the transport of sediment in a salt cavern storage tank under the coupled effects of multiple factors, and comprising the following steps:

[0024] S1. Parameter setting: Set the tilt angle of the formation dip simulation mechanism and select the injection mode of the multi-mode gas injection system as sequential injection or mixed injection;

[0025] S2. Establishing a background flow field: Gas is injected into the simulated gas injection chamber through the multi-mode gas injection system, and brine is discharged from the simulated brine discharge chamber through the brine circulation system to establish a stable injection and production background flow field.

[0026] S3. Applying seismic load: In the presence of the background flow field in step S2, the seismic simulation shaking table is started to apply a preset seismic simulation vibration to the system;

[0027] S4. Data Acquisition and Analysis: Throughout the process, the particle image velocimetry system is used to acquire dynamic image data of sediment transport, and the instability and transport patterns of sediment under the coupled effects of multiple factors such as formation dip angle, gas injection mode, injection and production background flow field and seismic vibration are analyzed.

[0028] In some embodiments, the method for simulating the migration of sediment in a salt cavern storage under the coupled effects of multiple factors further includes:

[0029] The influence of gas components on sediment transport characteristics was studied by adopting a mixed injection mode and changing the mixing ratio of cushion gas and hydrogen.

[0030] By applying the same seismic vibration under different dip angle settings, the amplification effect of the stratum dip angle on the instability and sliding distance of sediment under seismic disturbance was compared and analyzed.

[0031] Analyze the continuous images acquired by the particle image velocimetry system, calculate and compare the velocity field data when the same seismic vibration is applied with or without a background flow field, and quantify the coupling amplification effect between injection and mining operations and seismic load.

[0032] In some embodiments, the method for simulating the migration of sediment in a salt cavern storage under the coupled effects of multiple factors further includes:

[0033] The pressure balance compensation system was allowed to operate automatically during the experiment, and its trigger threshold or compensation rate was changed to study the effects of different compensation strategies on the stability of sediment under dynamic disturbance.

[0034] Compared with existing technologies, the beneficial effects of the apparatus and method for simulating the transport of sediment in salt cavern storage under the coupled effects of multiple factors provided by this invention are:

[0035] (1) Multiple key factors affecting sediment transport are integrated into a single experimental platform. It can not only simulate conventional injection and production operations, but also systematically introduce four core dimensions: gas composition (through a multi-mode gas injection system), geological morphology (through a formation dip simulation mechanism), critical safety operations (through a pressure balance compensation system), and extreme disaster loads (through a seismic simulation shaking table). This high degree of integration allows the experimental conditions to approximate real and complex engineering environments to the greatest extent possible, significantly improving the fidelity of the simulation.

[0036] (2) This scheme can study the risk amplification mechanism under the coupling effect of multiple factors. For example, by applying an earthquake during the simulated injection and production process (with background flow field), the superposition effect of "operating flow field + seismic disturbance" under the "worst case" can be quantitatively analyzed, revealing the real risks of sediment instability and migration. This is something that existing single-factor simulation devices cannot achieve, filling a gap in the understanding of this field.

[0037] (3) The high-precision, quantitative experimental data obtained through this scheme can directly serve engineering practice. For example, the experimental results can be used to guide the site selection assessment, safety design, optimization of the cushion gas to hydrogen ratio of salt cavern storage, and the development of more scientific emergency plans and operating procedures, which has very clear and important engineering application value. Attached Figure Description

[0038] Figure 1 This is a schematic diagram of the overall structure of a device for simulating the transport of sediment in a salt cavern storage under the coupling effect of multiple factors, provided in an embodiment of the present invention.

[0039] Figure 2 yes Figure 1 Enlarged structural schematic diagram of the salt cavern simulation system, the formation dip angle simulation mechanism, and the particle image velocimetry system;

[0040] Figure 3 yes Figure 2 The enlarged structural diagram of section A shows in detail the adjustment rod connection structure of the formation dip angle simulation mechanism;

[0041] Figure 4 This is a schematic diagram of the structure of the device in an inclined state in an embodiment of the present invention.

[0042] Figure reference numerals: 100 - Seismic simulation shaking table; 200 - Stratum dip angle simulation mechanism; 210 - Fixing plate; 211 - First hinge block; 212 - First fixing block; 220 - Mounting plate; 221 - Second hinge block; 222 - Second fixing block; 230 - Adjusting rod; 300 - Salt cavern simulation system; 310 - Simulated gas injection chamber; 311 - Sediment particles; 320 - Simulated brine discharge chamber; 330 - Connecting channel; 400 - Multi-mode gas injection system; 410 - First gas source; 411 - First gas tank; 412 - First gas outlet pipe; 413 - First gas pump; 414 420-First air valve; 421-Second air source; 422-Second air tank; 423-Second air outlet pipe; 424-Second air pump; 425-Second air valve; 430-Main injection pipe; 440-Second pressure detection element; 450-Flow meter; 500-Brine circulation system; 510-Discharge pipe; 520-Collection tank; 530-Discharge valve; 600-Pressure balance compensation system; 610-Pressure balance pipe; 620-First pressure detection element; 630-Control valve; 700-Particle image velocimetry system; 710-High frequency laser; 720-High speed camera; 730-Bracket. Detailed Implementation

[0043] The technical solutions in the embodiments of the present invention will be further described in detail below with reference to the accompanying drawings. The described embodiments are only possible technical implementations of the present invention, but are not limited thereto. Other embodiments obtained by those skilled in the art in conjunction with the embodiments of the present invention without creative effort are also within the protection scope of the present invention.

[0044] This application mainly adopts an integrated six-system simulation of salt cavern sediment transport, achieving a comprehensive simulation of multi-factor coupled operating conditions, and providing a basis for salt cavern energy storage safety research. The following is a further detailed description of this application.

[0045] Example 1

[0046] Please refer to Figure 1The apparatus for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors provided in this application includes a salt cavern simulation system 300, a multi-mode gas injection system 400, a brine circulation system 500, a formation dip angle simulation mechanism 200, a seismic simulation shaking table 100, a pressure balance compensation system 600, and a particle image velocimetry system 700. The salt cavern simulation system 300 is fixed to the formation dip angle simulation mechanism 200, which is mounted on the seismic simulation shaking table 100. The system 400 is connected to the simulated gas injection chamber 310 of the salt cavern simulation system 300, the brine circulation system 500 is connected to the simulated brine discharge chamber 320, the pressure balance compensation system 600 connects the top gas phase space of the simulated gas injection chamber 310 and the simulated brine discharge chamber 320, and the particle image velocimetry system 700 is used to monitor the sediment movement within the salt cavern simulation system 300. This achieves a highly integrated and systematic simulation of various real-world working conditions and extreme load coupling effects, providing a scientific basis for risk assessment and safety design of next-generation storage facilities such as salt cavern hydrogen storage facilities. This is because the various systems work together to simulate different gas environments, formation dip angles, seismic loads, and other factors, and can perform high-precision quantitative analysis of the sediment movement process.

[0047] For details, please refer to Figure 2 The salt cavern simulation system 300 includes a simulated gas injection chamber 310 and a simulated brine discharge chamber 320. The bottoms of the simulated gas injection chamber 310 and the simulated brine discharge chamber 320 are connected by a connecting channel 330. The bottom of the simulated gas injection chamber 310 contains sediment particles 311 and fluid tracer particles. The simulated gas injection chamber 310 and the simulated brine discharge chamber 320 can be made of transparent materials, such as plexiglass, to facilitate observation of the internal conditions; other high-strength, corrosion-resistant materials can also be used. The connecting channel 330 can be a circular or square pipe, its function being to allow fluid flow between the bottoms of the two chambers. Before the experiment begins, a layer of sediment particles 311 and fluid tracer particles for particle image velocimetry are pre-laid on the bottom of the simulated gas injection chamber 310.

[0048] Specifically, the multi-mode gas injection system 400 is connected to the simulated gas injection chamber 310. The multi-mode gas injection system 400 includes at least an independently controllable first gas source 410 and a second gas source 420, and can supply gas to the simulated gas injection chamber 310 in a sequential injection or a mixed injection according to a preset ratio. The first gas source 410 and the second gas source 420 can be a cushion gas source and a hydrogen gas source, respectively, to simulate hydrogen storage conditions with different cushion gas ratios. The system can realize two key injection modes: one is "sequential injection," which is used to simulate the process of injecting cushion gas first in the initial stage of the tank construction; the other is "mixed injection according to a preset ratio."

[0049] Please refer to Figure 1 and Figure 2The multi-mode gas injection system 400 also includes a main injection pipe 430, one end of which is connected to the simulated gas injection chamber 310. A second pressure detection element 440 and a flow meter 450 are installed on the main injection pipe 430. The first gas source 410 includes a first gas tank 411, a first gas outlet pipe 412, and a first gas pump 413. The first gas tank 411 is used to store a first gas. One end of the first gas outlet pipe 412 is connected to the outlet of the first gas tank 411. A first gas valve 414 is installed on the first gas outlet pipe 412. The inlet of the first gas pump 413 is connected to the other end of the first gas outlet pipe 412, and the outlet of the first gas pump 413 is connected to the main injection pipe 430. The second gas source 420 includes a second gas tank 421, a second gas outlet pipe 422, and a second gas pump 423. The second gas tank 421 stores a second gas. One end of the second gas outlet pipe 422 is connected to the outlet of the second gas tank 421, and a second gas valve 424 is installed on the second gas outlet pipe 422. The inlet of the second gas pump 423 is connected to the other end of the second gas outlet pipe 422, and the outlet of the second gas pump 423 is connected to the main injection pipe 430. The gas tank can be made of high-strength metal to ensure safe gas storage. The gas pump can be an electric gas pump or a pneumatic gas pump, and its function is to provide power for gas injection. The gas valve can be a manual valve or an electric valve, which facilitates the control of gas on / off and flow rate. By controlling the first gas valve 414, the first gas pump 413, the second gas valve 424, and the second gas pump 423, precise adjustment and mixing of different gas flow rates can be achieved.

[0050] Specifically, the brine circulation system 500 is connected to the simulated brine discharge chamber 320 for discharging brine at a controlled rate. The brine circulation system 500 may include a discharge pipe 510 and a collection tank 520. One end of the discharge pipe 510 is connected to the upper part of the simulated brine discharge chamber 320, and the other end of the discharge pipe 510 is connected to the collection tank 520. A discharge valve 530 is provided on the discharge pipe 510 for controlling the discharge rate.

[0051] For details, please refer to Figure 2 and Figure 3The formation dip angle simulation mechanism 200 includes a fixed plate 210, a mounting plate 220, and several adjusting rods 230 of different lengths. The fixed plate 210 is fixed to the seismic simulation shaking table 100. The mounting plate 220 is used to fix and install the salt cavern simulation system 300. A first hinge block 211 is formed on the fixed plate 210, and a second hinge block 221 is formed on the mounting plate 220. The second hinge block 221 is hinged to the first hinge block 211. One end of the adjusting rod 230 is detachably connected to the first fixed block 212 formed on the fixed plate 210, and the other end of the adjusting rod 230 is detachably connected to the second fixed block 222 formed on the mounting plate 220. By selecting adjusting rods 230 of different lengths connected between the first fixed block 212 and the second fixed block 222, the dip angle of the mounting plate 220 can be adjusted. The fixed plate 210 and the mounting plate 220 can be made of steel plate to ensure their strength and stability. The adjusting rod 230 can be a metal rod, and adjusting rods 230 of different lengths can be pre-processed for easy replacement as needed.

[0052] For details, please refer to Figure 1 and Figure 4 The earthquake simulation shaking table 100 can input real seismic wave data to reproduce seismic loads of different magnitudes and types. The earthquake simulation shaking table 100 can be either an electric or hydraulic shaking table, and its programmable control allows it to apply real seismic loads to the entire system. It is a programmable control platform capable of inputting real seismic wave data (such as time history curves of P-waves and S-waves), thereby accurately reproducing seismic loads of different magnitudes and spectral characteristics. During the experiment, the shaking table causes all systems above it to vibrate together, simulating the seismic effects on the entire salt cavern storage during an earthquake. This is a prerequisite for studying earthquake-induced sediment instability and liquefaction.

[0053] For details, please refer to Figure 1 and Figure 2 The pressure balance compensation system 600 includes a pressure balance pipe 610, two first pressure detection elements 620, and a control valve 630. The two ends of the pressure balance pipe 610 are connected to a simulated air injection chamber 310 and a simulated brine discharge chamber 320, respectively. The two first pressure detection elements 620 are respectively disposed at both ends of the pressure balance pipe 610. The control valve 630 is disposed on the pressure balance pipe 610 and located between the two first pressure detection elements 620. The pressure balance pipe 610 can be a metal pipe to ensure its sealing and pressure resistance. The first pressure detection elements 620 can be pressure sensors capable of real-time pressure monitoring. The control valve 630 can be an electrically adjustable valve that automatically opens to compensate for pressure when the pressure difference between the two chambers exceeds a threshold.

[0054] For details, please refer to Figure 2The particle image velocimetry system 700 includes a high-frequency laser 710 and a high-speed camera 720. The high-frequency laser 710 is fixed on a mounting plate 220 and is used to emit sheet-like light to illuminate the measurement plane within the connecting channel 330. The high-speed camera 720 is used to continuously capture images of the illuminated sediment particles 311 and fluid tracer particles within this plane. The high-frequency laser 710 can be a pulsed laser, whose emitted sheet-like light can uniformly illuminate the measurement plane. The high-speed camera 720 is fixed on the mounting plate 220 via a bracket 730. It can be a CCD camera with high resolution and high frame rate, capable of clearly capturing motion images of sediment particles 311 and fluid tracer particles. By performing professional algorithm analysis on the acquired continuous images, a high-resolution velocity vector field can be generated, thereby achieving precise quantitative analysis of sediment transport velocity, trajectory, and instability processes, which is more scientific and accurate than traditional macroscopic observation.

[0055] The implementation principle of this embodiment is as follows: This device integrates multiple systems to simulate the conditions of salt cavern storage under various real-world operating conditions and extreme load coupling effects. The multi-mode gas injection system 400 can simulate different gas environments, the brine circulation system 500 establishes a stable injection-production background flow field, the formation dip angle simulation mechanism 200 can adjust the tilt angle of the salt cavern simulation system 300, the seismic simulation shaking table 100 applies seismic loads, the pressure balance compensation system 600 ensures pressure balance between the two chambers, and the particle image velocimetry system 700 performs high-precision quantitative analysis of sediment transport. The cooperation of these systems makes the experimental results closer to actual engineering conditions, providing a scientific basis for risk assessment and safety design of salt cavern energy storage. Compared with existing technologies, it can solve problems such as single-condition simulation, lack of geological and disaster factors, and inability to study coupling effects.

[0056] Example 2

[0057] Please refer to Figures 1-4 The method for simulating the migration of sediment in a salt cavern storage under the coupled effects of multiple factors provided in this application includes the following steps:

[0058] S1. Parameter Setting: Set the tilt angle of the formation dip simulation mechanism 200, and select either sequential injection or mixed injection for the multi-mode gas injection system 400. The choice of formation dip angle can be made based on the actual geological conditions of the salt mine. For the injection mode selection, if the goal is to study the initial reservoir construction process of cushion gas injection, the sequential injection mode can be selected; if the goal is to study the complex gas environment of cushion gas and working gas mixing after long-term operation, the mixed injection mode should be selected.

[0059] S2. Establishing the Background Flow Field: Gas is injected into the simulated gas injection chamber 310 through the multi-mode gas injection system 400, while brine is discharged from the simulated brine discharge chamber 320 through the brine circulation system 500, thus establishing a stable injection and extraction background flow field. During the gas injection and brine discharge processes, the gas injection rate and the brine discharge rate must be controlled according to the experimental requirements to ensure the formation of a stable flow field. The rate can be controlled by adjusting the speed of the gas pump and the circulation pump.

[0060] S3. Applying Seismic Load: Given the background flow field from step S2, the seismic simulation shaking table 100 is activated to apply preset seismic simulation vibrations to the system. The preset seismic simulation vibrations can be set based on actual seismic data, such as seismic waves of different magnitudes and types. The seismic simulation shaking table 100 will apply vibrations to the entire system according to the set parameters, simulating the disturbance of the internal dynamic environment of the salt cavern storage by an earthquake.

[0061] S4. Data Acquisition and Analysis: Throughout the process, the particle image velocimetry system 700 acquires dynamic image data of sediment transport and analyzes the instability and transport patterns of sediment under the coupled effects of multiple factors, including formation dip angle, gas injection mode, injection-production background flow field, and seismic vibration. The particle image velocimetry system 700 captures images of sediment particles 311 and fluid tracer particles within the connecting channel 330. By performing algorithmic analysis on these images, a high-resolution velocity vector field can be obtained, thereby quantitatively analyzing the transport patterns of sediment.

[0062] The implementation principle of this embodiment is as follows: This method, through systematic multi-factor coupling research, can gain a deep understanding of the migration patterns of sediment within salt cavern storage facilities under various real-world operating conditions and extreme load coupling effects. By setting different parameters and conditions, such as formation dip angle, gas injection mode, and seismic load, various actual situations can be simulated. Data is then collected and analyzed using a particle image velocimetry system 700, thereby revealing the risk amplification mechanism under multi-factor coupling effects. Compared to existing methods, this method can study the risk superposition effect under "worst-case" conditions such as earthquakes encountered during the injection and production process, providing a more scientific basis for risk assessment and safety design of next-generation storage facilities such as salt cavern hydrogen storage facilities.

[0063] The method for simulating sediment transport in salt cavern storage under the coupled effects of multiple factors provided in this application, in addition to the basic steps, also includes the following in-depth research on specific coupling effects:

[0064] (I) Quantitative Study on the Influence of Gas Components on Sediment Transport Characteristics

[0065] Detailed simulation process:

[0066] (1) Benchmark experiment: First, set a benchmark operating condition, for example, adopt the "sequential injection" mode, first inject 100% cushion gas (such as nitrogen, supplied by the first gas source 410) to establish a stable injection and production background flow field.

[0067] (2) Mixing ratio setting: Then, switch to the "mixing injection" mode and set a series of volume mixing ratios of hydrogen and cushion gas, such as 20%, 40%, 60%, and 80%, by precisely controlling the first gas pump 413, the second gas pump 423, the first gas valve 414 and the second gas valve 424.

[0068] (3) Constant boundary conditions: Under each mixing ratio, other experimental parameters such as total gas injection rate, brine discharge rate, formation dip angle and seismic load (or no seismic load) are kept constant to ensure that the variables are unique.

[0069] (4) Data acquisition: The particle image velocimetry system 700 was used to record the starting and migration process of sediment particles 311 under the disturbance of fluid with different gas components.

[0070] (5) By analyzing the data from the particle image velocimetry system 700, the critical injection velocity or flow field shear stress that can cause the sediment particles 311 to become unstable under different gas mixing ratios is determined. Then, the average sediment transport velocity, transport flux (mass of sediment passing through a specific cross section per unit time) and maximum transport distance under different working conditions are calculated and compared. Finally, the above quantitative results are correlated with the physical properties of different mixed gases, such as density and viscosity, to establish an empirical relationship or quantitative spectrum of gas component-sediment transport characteristics.

[0071] The technical advantages of this embodiment are as follows: This method no longer describes the influence of gas components in a general way, but through precise process control and quantitative evaluation, it can reveal the specific changes in fluid dynamics caused by the addition of hydrogen, and ultimately determine the safe hydrogen mixing ratio range that the storage facility should maintain at different operating stages (such as the initial, middle, and final stages) to ensure the long-term stability of the sludge. This provides a direct and quantifiable scientific basis for optimizing the operating parameters and mitigating risks of hydrogen storage facilities.

[0072] (II) Analysis of the amplification effect of stratigraphic dip angle on seismic disturbance

[0073] Detailed simulation process:

[0074] (1) Inclination setting: Using the formation inclination simulation mechanism 200, multiple simulated formation inclination angles can be set sequentially by changing the adjustment rods 230 of different lengths, such as 0° (horizontal), 5°, 10° and 15°.

[0075] (2) Apply standard seismic waves: At each dip setting, shut down the injection and production system (i.e., no background flow field) and apply identical, pre-recorded real seismic wave data (such as an El Centro wave of a specific magnitude) through the seismic simulation shaking table 100.

[0076] (3) Comparative observation: High-speed camera 720 was used to record the instability range of sediment under seismic action and the sliding process along the inclined bottom surface.

[0077] (4) Compare the lowest peak ground acceleration (PGA) that induces macroscopic sliding of sediment at different dip angles; then, use image processing software to accurately measure and compare the final sliding distance and average sliding velocity of sediment at different dip angles; finally, define a "pitch angle magnification factor", for example, take the sliding distance at 0° dip angle as the baseline 1, calculate the multiple of the relative sliding distance at other dip angles, and plot the "pitch angle-magnification factor" relationship curve.

[0078] The technical advantages of this embodiment are: This method can quantitatively reveal the sensitivity and amplification effect of the static geological factor of stratum dip angle on dynamic loads such as earthquakes. Its research results can be directly applied to the site selection assessment of salt cavern reservoirs, providing decision support for avoiding areas with large dip structures, or, when avoidance is not possible, providing key parameters for targeted engineering reinforcement and the development of earthquake emergency plans.

[0079] (III) Quantification of the coupling amplification effect between injection and production operations and seismic loads

[0080] Detailed simulation process:

[0081] (1) Condition A (isolated earthquake): Set a dip angle (e.g., 5°), do not turn on the injection and extraction system, apply only one standard simulated earthquake, and collect data using the particle image velocity system 700.

[0082] (2) Condition B (coupling effect): Keep the inclination angle unchanged. First, establish a stable injection and production background flow field through the multi-mode gas injection system 400 and brine circulation system 500. After the flow field stabilizes, apply the same standard simulated earthquake as in Condition A and collect data synchronously.

[0083] (3) Repeated verification: Multiple sets of working condition B experiments under different injection and extraction rates can be repeated to study the influence of background flow fields of different intensities on coupling effects.

[0084] (4) Directly compare and analyze the velocity vector fields generated by the particle image velocimetry system 700 under operating conditions A and B. Focus on the peak velocity, average kinetic energy, and range of the disturbed area of ​​sediment particles 311. Next, quantify and calculate the "coupling amplification factor," for example, factor = (peak velocity of operating condition B - peak velocity of operating condition A) / peak velocity of operating condition A. A factor much greater than 0 indicates a significant coupling amplification effect. Finally, based on this factor, assess how much the risk of sediment instability increases under the extreme condition of "seismic event during injection and production" compared to a single earthquake.

[0085] The technical advantages of this embodiment: The core innovative value of this method lies in its scientific reproduction and quantification of the risk superposition effect under the "worst-case" scenario, solving the pain point that existing technologies cannot study such coupled problems. Experimental results demonstrate that a simple linear superposition of risks (injection-production risk + seismic risk) severely underestimates the actual risks, thus providing irreplaceable experimental data support for establishing a more realistic and conservative safety evaluation system and emergency operating procedures for salt cavern reservoirs.

[0086] (IV) Research on the Influence of Pressure Balance Compensation Strategy on the Stability of Sediment under Dynamic Disturbance

[0087] Detailed simulation process:

[0088] (1) Creating dynamic disturbances: After establishing a stable background flow field, the multi-mode gas injection system 400 is controlled by the program to simulate a rapid pressure increase or decrease operation, artificially creating a significant pressure difference between the simulated gas injection chamber 310 and the simulated brine discharge chamber 320.

[0089] (2) Set the compensation strategy: Set the parameters of the pressure balance compensation system 600. For example, conduct two sets of experiments: one set a lower trigger threshold (e.g., compensation is activated when the pressure difference reaches 0.1 bar) and a faster compensation rate; the other set a higher trigger threshold (e.g., 0.5 bar) and a slower compensation rate.

[0090] (3) Monitoring system response: When the pressure compensation system 600 is running automatically, the particle image velocity measurement system 700 is used to monitor the stability of the sediment near the connecting channel 330, and the first pressure detection element 620 is used to record the pressure change curves of the two chambers.

[0091] (4) By analyzing the images from the high-speed camera 720, it is determined whether the pressure balancing process itself will cause secondary sediment disturbance under different compensation strategies. Then, the pressure curves under different strategies are compared to evaluate their efficiency and stability in controlling differential pressure and avoiding negative pressure risks. Finally, by combining sediment stability and pressure control effect, an optimal combination of compensation strategies (i.e., trigger threshold and compensation rate) is found that can ensure safety and will not cause additional disturbance to the sediment at the bottom of the reservoir.

[0092] The technical effects of this embodiment: This study treats the "safe operation" of the pressure compensation system 600 itself as a potential source of disturbance, filling a gap in related research. Through experiments, the design and verification of the pressure balance control logic can be optimized, avoiding new safety risks caused by improper compensation operations (such as excessively rapid pressurization). This makes the safety design and operating procedures of the entire storage facility more refined and reliable, and improves the risk assessment system under the coupling effect of multiple factors.

[0093] The beneficial effects of the technical solution provided in this application include:

[0094] (1) Multiple key factors affecting sediment transport are integrated into an experimental platform. It can not only simulate conventional injection and production operations, but also systematically introduce four core dimensions: gas composition (through the multi-mode gas injection system 400), geological morphology (through the formation dip angle simulation mechanism 200), key safety operations (through the pressure balance compensation system 600), and extreme disaster loads (through the earthquake simulation shaking table 100). This high degree of integration allows the experimental conditions to approximate real and complex engineering environments to the greatest extent, significantly improving the fidelity of the simulation.

[0095] (2) This scheme can study the risk amplification mechanism under the coupling effect of multiple factors. For example, by applying an earthquake during the simulated injection and production process (with background flow field), the superposition effect of "operating flow field + seismic disturbance" under the "worst case" can be quantitatively analyzed, revealing the real risks of sediment instability and migration. This is something that existing single-factor simulation devices cannot achieve, filling a gap in the understanding of this field.

[0096] (3) The high-precision, quantitative experimental data obtained through this scheme can directly serve engineering practice. For example, the experimental results can be used to guide the site selection assessment, safety design, optimization of the cushion gas to hydrogen ratio of salt cavern storage, and the development of more scientific emergency plans and operating procedures, which has very clear and important engineering application value.

[0097] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A device for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors, characterized in that, include: The salt cavern simulation system (300) includes a simulated gas injection chamber (310) and a simulated brine discharge chamber (320). The bottom of the simulated gas injection chamber (310) and the bottom of the simulated brine discharge chamber (320) are connected by a connecting channel (330). The bottom of the gas injection chamber (310) is deposited with sediment particles and fluid tracer particles. A multi-mode gas injection system (400) is connected to the simulated gas injection chamber (310). The multi-mode gas injection system (400) includes at least a first gas source (410) and a second gas source (420) that can be controlled independently, and can supply gas to the simulated gas injection chamber (310) in a sequential injection or mixed injection manner according to a preset ratio. A brine circulation system (500) is connected to the simulated brine discharge chamber (320); A formation dip angle simulation mechanism (200) is used to fix and install the salt cave simulation system (300) to adjust the overall tilt angle of the salt cave simulation system (300); An earthquake simulation shaking table (100) is provided, on which the stratum dip angle simulation mechanism (200) is disposed, for applying programmable earthquake simulation vibration to the entire system; A pressure balance compensation system (600) connects the top gas phase space of the simulated gas injection chamber (310) and the top gas phase space of the simulated brine discharge chamber (320). The pressure balance compensation system (600) is used to automatically perform gas compensation when the pressure difference between the two chambers exceeds a preset threshold. A particle image velocimetry system (700) is used to quantitatively capture and analyze the transport process of sediment within the connecting channel (330).

2. The device for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors as described in claim 1, characterized in that, The pressure balance compensation system (600) includes a pressure balance pipe (610), two first pressure detection elements (620) and a control valve (630). The two ends of the pressure balance pipe (610) are respectively connected to the simulated gas injection chamber (310) and the simulated brine discharge chamber (320). The two first pressure detection elements (620) are respectively disposed at the two ends of the pressure balance pipe (610). The control valve (630) is disposed on the pressure balance pipe (610) and located between the two first pressure detection elements (620).

3. The device for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors as described in claim 1, characterized in that, The multi-mode gas injection system (400) has two gas sources: a cushion gas source and a hydrogen gas source, which are used to simulate hydrogen storage conditions with different cushion gas ratios.

4. The device for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors as described in claim 1, characterized in that, The multi-mode gas injection system (400) also includes a main injection pipe (430), one end of which is connected to the simulated gas injection chamber (310), and a second pressure detection element (440) and a flow meter (450) are provided on the main injection pipe (430); The first gas source (410) includes a first gas tank (411), a first gas outlet pipe (412), and a first gas pump (413). The first gas tank (411) is used to store a first gas. One end of the first gas outlet pipe (412) is connected to the outlet of the first gas tank (411). A first gas valve (414) is provided on the first gas outlet pipe (412). The inlet of the first gas pump (413) is connected to the other end of the first gas outlet pipe (412). The outlet of the first gas pump (413) is connected to the main injection pipe (430). The second gas source (420) includes a second gas tank (421), a second gas outlet pipe (422), and a second gas pump (423). The second gas tank (421) is used to store a second gas. One end of the second gas outlet pipe (422) is connected to the outlet of the second gas tank (421). A second gas valve (424) is provided on the second gas outlet pipe (422). The inlet of the second gas pump (423) is connected to the other end of the second gas outlet pipe (422). The outlet of the second gas pump (423) is connected to the main injection pipe (430).

5. The device for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors as described in claim 1, characterized in that, The earthquake simulation shaking table (100) can input real seismic wave data to reproduce earthquake loads of different magnitudes and types.

6. The apparatus for simulating the transport of sediment in a salt cavern storage tank under the coupled effects of multiple factors as described in claim 1, characterized in that, The formation dip angle simulation mechanism (200) includes a fixed plate (210), a mounting plate (220), and several adjusting rods (230) of different lengths. The fixed plate (210) is fixed to the earthquake simulation shaking table (100), and the mounting plate (220) is used to fix and install the salt cave simulation system (300). A first hinge block (211) is formed on the fixed plate (210), and a second hinge block (221) is formed on the mounting plate (220). 1) Hinged to the first hinge block (211), one end of the adjusting rod (230) is detachably connected to the first fixing block (212) formed on the fixing plate (210), and the other end of the adjusting rod (230) is detachably connected to the second fixing block (222) formed on the mounting plate (220). By selecting adjusting rods (230) of different lengths to connect between the first fixing block (212) and the second fixing block (222), the tilt angle of the mounting plate (220) can be adjusted.

7. The apparatus for simulating the transport of sediment in a salt cavern storage tank under the coupled effects of multiple factors as described in claim 1, characterized in that, The particle image velocimetry system (700) includes a high-frequency laser (710) and a high-speed camera (720). The high-frequency laser (710) is used to emit sheet light to illuminate the measurement plane in the connecting channel (330), and the high-speed camera (720) is used to continuously capture images of the illuminated sediment particles and fluid tracer particles in the plane.

8. A method for simulating sediment transport in salt cavern storage under the coupled effects of multiple factors, characterized in that, An apparatus for simulating the transport of sediment in a salt cavern storage under the coupled effects of multiple factors, as described in any one of claims 1-7, and comprising the following steps: S1. Parameter setting: Set the tilt angle of the formation dip simulation mechanism (200) and select the injection mode of the multi-mode gas injection system (400) as sequential injection or mixed injection; S2. Establishing a background flow field: Gas is injected into the simulated gas injection chamber (310) through the multi-mode gas injection system (400), and brine is discharged from the simulated brine discharge chamber (320) through the brine circulation system (500) to establish a stable injection and extraction background flow field. S3. Applying seismic load: In the presence of the background flow field in step S2, the seismic simulation shaking table (100) is started to apply a preset seismic simulation vibration to the system; S4. Data Acquisition and Analysis: Throughout the process, the particle image velocimetry system (700) is used to acquire dynamic image data of sediment transport, and the instability and transport patterns of sediment under the coupled effects of multiple factors such as formation dip angle, gas injection mode, injection and production background flow field and seismic vibration are analyzed.

9. The method for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors, as described in claim 8, is characterized in that... Also includes: The influence of gas components on sediment transport characteristics was studied by adopting a mixed injection mode and changing the mixing ratio of cushion gas and hydrogen. By applying the same seismic vibration under different dip angle settings, the amplification effect of the stratum dip angle on the instability and sliding distance of sediment under seismic disturbance was compared and analyzed. Analyze the continuous images acquired by the particle image velocimetry system (700), calculate and compare the velocity field data when the same seismic vibration is applied with or without a background flow field, and quantify the coupling amplification effect between injection and mining operations and seismic load.

10. The method for simulating the transport of sediment in a salt cavern storage reservoir under the coupled effects of multiple factors, as described in claim 8, is characterized in that... Also includes: The pressure balance compensation system (600) is allowed to operate automatically during the experiment, and its trigger threshold or compensation rate is changed to study the effect of different compensation strategies on the stability of sediment under dynamic disturbance.

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