Experimental device for simulating brine-sediment migration characteristics of salt-cavern gas storage under action of air pressure rise and fall

Abstract

The utility model provides an experimental device for simulating brine-sediment migration characteristics of a salt-cavern gas storage under the action of air pressure rise and fall. The experimental device comprises a gas injection system, a simulated salt cavity, a gas production system, a brine discharge system, a temperature regulation and control system and a pore pressure measurement system. The gas injection system is connected with the simulated salt cavity through a gas injection pipe; the gas production system is connected with the simulated salt cavity through an exhaust pipe; the simulated salt cavity and the brine discharging system are connected through a simulated brine discharging pipe and a water discharging pipe; and the temperature regulation and control system and the pore pressure measurement system are connected with the simulated salt cavity through pipelines. The experimental device disclosed by the utility model is reasonable in design, and can be used for researching the migration law of brine and sediment under a free sinking condition, the evolution law of a sediment gap structure under the action of self-weight compaction and the secondary migration law of brine and sediment under gas injection and production through an indoor simulation experiment, thereby providing reference for reasonable setting of injection and production operation parameters of the salt-cavern gas storage.

Description

Technical Field

[0001] The utility model relates to an experimental device for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of air pressure lifting, and belongs to the technical field of gas injection and production simulation of salt cavern gas storage. Background Technique

[0002] In recent years, domestic and foreign scholars have carried out a large number of studies on the sediment in salt cavern gas storage, including aspects such as the sediment formation process, physical and chemical properties, accumulation form, stress state, space utilization, and its impact on the stability of the gas storage. Research shows that the void space of the sediment has a certain gas storage capacity, and it is a trend to use the effective void space of the sediment for gas storage in the future. However, in current research, the research on the migration characteristics of sediment-brine is relatively less, and the focus is limited. For salt cavern gas storage with high impurities, the sediment occupies most of the volume of the salt cavity. The migration of sediment and brine has a greater impact on the dynamic inner boundary conditions of the gas storage, and the change in the position of the gas-water interface it brings also affects the sinking depth of the pipe string, threatening the safe and stable operation of the gas storage.

[0003] CN117780340A has developed a simulation test device and method for gas displacement of brine in salt cavern sediment. The simulation test device includes an air injection device, a salt cavity simulation device, and a recovery device. Among them, the air injection device is connected to the salt cavity simulation device through an air injection pipe. A simulated brine discharge pipe string is arranged inside the salt cavity simulation device, and the simulated brine discharge pipe string and the recovery device are connected through a liquid discharge pipe. By injecting gas into the simulated salt cavity through the air injection device, the residue particles and brine are discharged from the simulated brine discharge pipe and enter the recovery device, thereby studying the flow law of gas displacement of brine in the salt cavity sediment. Also, through the setting of a mechanical sand control and adding a chemical sand control agent control test scheme, the clogging law of sediment particles in the brine discharge pipe string and the salt crystallization clogging law of the brine discharge pipe string are further studied.

[0004] CN116413394A has developed an evaluation device and method for the void utilization ability of the residue at the bottom of a salt cavern gas storage. The evaluation device for the void utilization ability of the residue at the bottom of a salt cavern gas storage includes: a simulated salt cavity, a gas pressurization system, a top air inlet valve, a top liquid inlet valve, a bottom air inlet valve, a bottom vent valve, a water injection pump, and a water storage tank. Among them, the top of the simulated salt cavity is connected to the top air inlet valve and the top liquid inlet valve through pipelines. Similarly, the bottom of the simulated salt cavity is connected to the bottom vent valve and the bottom air inlet valve through pipelines. The gas pressurization system, the top air inlet valve, and the bottom air inlet valve are connected together through pipelines. The gas pressurization system and the bottom liquid discharge valve are connected to the water injection pump through pipelines, and the water storage tank is connected to the water injection pump. The sediment is loaded at the bottom of the simulated salt cavity, and the brine is placed in the water storage tank. An evaluation method for the void utilization ability of the residue at the bottom of a salt cavern gas storage is proposed. By injecting gas to discharge brine to evaluate the gas storage capacity of the void space of the sediment.

[0005] The above invention mainly focuses on studying the law of gas-driven brine drainage in sediment and evaluating the gas storage capacity of the void space in sediment. However, the focus of the present utility model is on studying the migration law of sediment and brine under temperature load and air pressure. Therefore, the present utility model has developed an experimental device for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of air pressure rise and fall. Summary of the Utility Model

[0006] The technical solution of the present utility model is as follows: An experimental device for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of air pressure rise and fall is developed, which includes an air injection system, a gas extraction system, a brine drainage system, a simulated salt cavity, a temperature control system, and a pore pressure measurement system. The air injection system consists of a nitrogen cylinder, a buffer bottle, an air injection pipe, a first pressure gauge, a first control valve, a second control valve, a third control valve, and a fourth control valve. The air injection pipe can be connected to the air injection hole on the cover plate of the simulated salt cavity. The simulated salt cavity includes a scaled simulated salt cavity side wall, a cover plate, and a base. During the experiment, the base is connected to the side wall of the pressure chamber with fixing bolts, and the simulated salt cavity side wall is installed, and then sediment and brine are added. The gas extraction system consists of a gas storage cylinder, an exhaust pipe, and a fifth control valve. The exhaust pipe can be connected to the exhaust hole on the cover plate. The brine drainage system includes a simulated brine drainage pipe, a drainage pipe, a sixth control valve, a seventh control valve, and a measuring cup. Similarly, the brine drainage pipe can be connected to the brine drainage hole on the cover plate. The temperature control system includes the side wall of the pressure chamber, a semi-cylindrical electric heating plate of the pressure chamber, a thermocouple of the pressure chamber, a temperature controller of the pressure chamber, the side wall of the water container, an electric heating plate of the water container, a thermocouple of the water container, the base of the water container, and a temperature controller of the water container. The pore pressure measurement system includes a permeable stone, a pore water pressure measurement hole, a pore water pressure measurement pipe, a pore pressure sensor, a data collector, and a result display terminal. The temperature control system and the pore pressure measurement system are connected to the simulated salt cavity through pipelines.

[0007] The sediment used in the present utility model can be an actual sediment sample or a sediment experimental sample prepared artificially according to the test results of on-site sediment physical property experiments.

[0008] The brine used in the present utility model is artificially prepared saturated brine.

[0009] The simulated salt cavity described in the present utility model includes a transparent cylindrical container, a transparent cube container, or a transparent cuboid container. The transparent cylindrical container includes a cover plate, a simulated salt cavity side wall, and a simulated salt cavity base.

[0010] The simulated salt cavity side wall of the present utility model uses a transparent acrylic cylindrical tube (with scale).

[0011] The cover plate of the utility model is provided with an injection gas pipe penetration hole, an exhaust gas pipe penetration hole, a liquid level measurement hole, a brine discharge hole and a thermocouple penetration hole; a liquid level sensor is arranged on the cover plate, referring to the MIK-MP ultrasonic liquid level gauge, which can monitor the change of the brine level; the cover plate and the side wall of the simulated salt cavity are connected by a flange.

[0012] The simulated brine discharge pipe and the drain pipe use stainless steel hoses.

[0013] The liquid inlet of the simulated brine discharge pipe is provided with a sieve hole, and the direct product of the sieve hole is 2 mm.

[0014] The bottom of the simulated brine discharge pipe is sealed, and a liquid inlet is arranged on the right side of the lower end. The pipe orifice is treated to prevent sand, and mechanical sand prevention (setting a sand prevention belt) or chemical sand prevention (sand consolidating agent: epoxy resin and phenolic resin foam solution) can be adopted.

[0015] The injection gas pipe is provided with a first control valve, a second control valve, a third control valve, a fourth control valve, a first pressure gauge and a second pressure gauge. The second control valve and the third control valve control the intake air volume of the buffer bottle, and the first pressure gauge can monitor the pressure of the buffer bottle in real time; the intake air volume of the cavity can be controlled through the fourth control valve, and the cavity pressure can be monitored in real time through the second pressure gauge, so that different injection gas pressures can be adjusted during the simulation experiment; all the above valves and pressure gauges can cooperate to measure the sediment void ratio. The pressure gauge refers to a digital display pressure gauge, which has an RS485 interface.

[0016] The gas extraction pipe is provided with a fifth control valve.

[0017] The drain pipe is provided with a sixth control valve and a seventh control valve, which can control the drainage volume.

[0018] The valve adopts a one-way valve, which can prevent the backflow of liquid and gas, and improve the stability and reliability of the device;

[0019] The pore water pressure measuring pipe is provided with an eighth control valve.

[0020] In the embodiment of the utility model, the height of the side wall of the simulated salt cavity is 30 cm, and its diameter is 20 cm. The diameters of the injection gas hole, the gas extraction hole, the liquid level measurement hole, the brine discharge hole and the temperature measurement hole are all 2 cm, and the intervals between the injection gas hole, the gas extraction hole, the liquid level measurement hole, the brine discharge hole and the temperature measurement hole are also 2 cm. The heights of the injection gas round pipe, the gas extraction round pipe, the liquid level measurement round pipe, the brine discharge round pipe and the temperature measurement round pipe are all 4 cm, and they are separated by 0.5 cm.

[0021] The side wall of the pressure chamber of the utility model is made of stainless steel material. The semi-cylindrical electric heating plate of the pressure chamber is embedded in the side wall of the pressure chamber, and the two ends of its resistance wire are connected with a temperature regulator. The outside of the electric heating plate is filled with asbestos for heat insulation.

[0022] Since the gas injection system and the brine drainage system are under room temperature conditions (such as 25°C), while the temperature of the brine in the simulated salt cavity is under the set temperature (such as 50.5°C), it causes a temperature gradient distribution of the water in the drain pipe, which affects the measurement accuracy. Therefore, the drain pipe and the pore water pressure measuring pipe are placed in a water container with a constant temperature. In this way, the temperature change in the simulated salt cavity will not affect the measurement of the water volume, so that the pore water pressure of the sediment and the volume of the discharged brine can be accurately measured.

[0023] Since the plastic drain pipe and the pore water pressure measuring pipe have a large coefficient of thermal expansion, which will bring great errors to the experimental results, the drain pipe and the pore water pressure measuring pipe of the present utility model are made of stainless steel material, and the middle section is a spiral structure. The spiral section is located in the normal temperature water container and can exchange heat with the water body.

[0024] The airtightness of the experimental device should be checked before use. The steps for checking the airtightness of the device include opening the first control valve and the fourth control valve, closing other control valves, starting the nitrogen cylinder, adjusting the gas injection pressure, slowly increasing the pressure to the experimental test pressure, and checking whether each device of the experimental system leaks; after the test, stop injecting gas, open the fifth control valve, and collect gas to relieve pressure.

[0025] The present utility model also provides an experimental method for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of air pressure rise and fall, which is carried out by using the above-mentioned simulation experimental device. The experimental method includes a simulation experimental method for the migration law of brine and sediment under the condition of free sinking, a simulation experimental method for the evolution law of the void structure of sediment under the action of self-weight compaction, and a simulation experimental method for the secondary migration law of brine and sediment under gas injection and production, as Figure 3 shown.

[0026] (1) The simulation experimental method for the migration law of brine and sediment under the condition of free sinking includes the following steps:

[0027] Step 1: Connect the side wall of the pressure chamber with the base of the simulated salt cavity by using fixing bolts and O-ring rubber gaskets, and then install the side wall of the simulated salt cavity. Prepare saturated brine and sediment particle samples with different particle size ranges (part of tracer sand is added to the sediment particles), and first pour the brine into the simulated salt cavity.

[0028] Step 2: Start the temperature control device, control the temperature at 50.5°C to simulate the temperature of the real salt cavity, and at the same time set multiple sets of control experiments, and set the sediment falling height and the sediment particle size range as variables.

[0029] Step 3: Pour a group of sediment into the open container at a constant speed from a certain height until the brine level is 2-3 cm higher than the sediment surface.

[0030] Step 4: Let the experimental device stand still to allow the sediment particles to settle fully. During this process, seal the simulated salt cavity device with a cover plate. Observe the flow pattern of the tracer sand in the closed container, take pictures to record the migration law of the brine and sediment particles, and record the change in the pore pressure of the sediment. After the sediment settlement is stable, take pictures to record the stratified settlement state of the sediment.

[0031] Step 5: Change the particle size range of the sediment particles or the falling height of the sediment. Prepare a new open container filled with saturated brine and repeat experimental steps 3 - 4 to analyze the migration law of the brine and sediment particles under different particle size ranges of sediment particles and different falling heights.

[0032] (2) The simulation experiment method for the migration law of brine and sediment under self - weight compaction conditions includes the following steps:

[0033] Step 1: Continuing from step 4 of the previous experiment, continue to let it stand and accumulate for 3 hours. Start the pore pressure measurement system. Record the pore water pressure of the sediment and the brine level every 30 minutes.

[0034] Step 2: Draw a curve graph showing the change of the pore water pressure of the sediment and the brine level with the compaction time. After 3 hours, connect the gas injection system and measure the void ratio of the sediment every 30 minutes. The gas injection pressure is 0.3 MPa, and record the change in the void ratio of the sediment.

[0035] Step 3: Change the particle size range of the sediment particles and repeat steps 1 - 2. Analyze the migration characteristics of the brine and sediment under different self - weight compaction times and different particle size ranges of sediment particles.

[0036] (3) The simulation experiment method for the secondary migration law of brine and sediment under gas injection and production includes the following steps:

[0037] Step 1: Continuing from step 2 of the previous experiment, start to simulate the gas injection process. Inject gas under pressure, observe and record the change in the brine level and the sediment height, and at the same time record the change in the brine temperature and the pore water pressure of the sediment with time.

[0038] Step 2: Simulate the gas production process. Connect the gas production system, produce gas, observe and record the change in the brine level and the sediment height. Similarly, record the change in the brine temperature and the pore water pressure of the sediment with time.

[0039] Step 3: Measure the effective void ratio of the sediment. Connect the brine drainage system, inject gas to drain the brine, and record the volume of the drained brine. This volume is the void volume available for gas storage in the sediment.

[0040] Step 4: Change the particle size range of the sediment particles and repeat steps 1 - 2. Analyze the secondary migration law of the brine and sediment under the action of rising and falling gas pressure.

[0041] One to three layers of colored tracer sand are laid inside the sediment particles of the present utility model, which are used to analyze the flow laws of brine and sediment particles in the sediment during the experiment.

[0042] The principle of the device for measuring the porosity of sediment particles of the present utility model is as follows:

[0043] The porosity of sediment particles is measured using the principle of isothermal gas expansion. The specific operation is to perform isothermal expansion of a gas with a known volume and pressure into a container with an unknown volume, and measure the equilibrium pressure of the gas after expansion. According to the ideal gas state equation, we have:

[0044] P b V b =Z 1 n 1 RT 1 (1)

[0045] P a (V w +V v )=Z 2 n 2 RT 2 (2)

[0046] P e (V b +V w +V v )=Z 3 (n 1 +n 2 )RT 3 (3)

[0047] In the formula, P b is the pressure of the buffer bottle, Pa; P a is the local standard atmospheric pressure, Pa; P e is the equilibrium pressure, Pa; V b is the volume of the buffer bottle, m 3 ; V w is the net brine volume above the sediment; V v is the void volume of the sediment; R is the molar gas constant, taken as 8.314 J / (mol·K); Z 1 、Z 2 、Z 3 are the gas compressibility factors in the buffer bottle, pressure chamber, and after expansion during the experiment, respectively; T 1 、T 2 、T 3 are the temperatures (K) in the buffer bottle, pressure chamber, and after expansion, respectively; n 1 、n 2are the number of moles of gas in the buffer bottle and the pressure chamber respectively. During the gas expansion process, the pressure in the pressure chamber is the standard atmospheric pressure and the room temperature is 25°C. If the influence of gas pressure on the sediment particle volume and the change of gas compression factor are ignored, we have:

[0048] Z 1 = Z 2 = Z 3 (4)

[0049] T 1 = T 2 = T 3 (5)

[0050] By combining equations (1)-(5), we get:

[0051] P e (V b + V w + V v ) = P b V b + P a (V w + V v ) (6)

[0052] Also, from the sediment porosity formula:

[0053]

[0054] where V s is the total volume of the sediment accumulation at the lower part of the pressure chamber; n is the sediment porosity.

[0055] By combining equation (6) and equation (7), the calculation formula for the sediment particle porosity is obtained as follows:

[0056] BRIEF DESCRIPTION OF THE DRAWINGS

[0057] Figure 1 is a device for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of pneumatic pressure rise and fall provided by the present utility model.

[0058] Figure 2 is a schematic diagram of the simulated brine drainage pipe and sand control belt provided by the present utility model.

[0059] Figure 3 is a schematic diagram of the experimental scheme design for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of pneumatic pressure rise and fall provided by the present utility model.

[0060] Figure 4 is a flowchart of the experimental steps for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of pneumatic pressure rise and fall provided by the present utility model.

[0061] In the figure: 1 - fixing bolt; 2 - gas injection round tube; 3 - gas production round tube; 4 - brine drainage round tube; 5 - gas injection hole; 6 - gas production hole; 7 - brine drainage hole; 8 - temperature measurement hole; 9 - liquid level measurement hole; 10 - thermocouple of pressure chamber; 11 - temperature regulator of pressure chamber; 12 - side wall of simulated salt cavity; 13 - scale; 14 - side wall of pressure chamber; 15 - semi-cylindrical electric heating plate of pressure chamber; 16 - saturated brine; 17 - sediment particles; 18 - O-ring; 19 - permeable stone; 20 - base of pressure chamber; 21 - nitrogen cylinder; 22 - first control valve; 23 - second control valve; 24 - third control valve; 25 - first pressure gauge; 26 - buffer bottle; 27 - gas injection pipeline; 28 - fourth control valve; 29 - second pressure gauge; 30 - fifth control valve; 31 - gas production pipeline; 32 - gas storage cylinder; 33 - pore water pressure measurement hole; 34 - side wall of water container; 35 - electric heating plate of water container; 36 - thermocouple of water container; 37 - bracket; 38 - temperature regulator of water container; 39 - base of water container; 40 - eighth control valve; 41 - pore pressure sensor; 42 - data collector; 43 - result display terminal; 44 - simulated brine drainage pipe; 45 - sixth control valve; 46 - drain pipe; 47 - seventh control valve; 48 - measuring cup; 49 - sieve hole; 50 - sand control belt; 51 - gravel; 52 - liquid level measurement round tube; 53 - temperature measurement round tube. Specific implementation manner

[0062] As Figure 4 shown, an experimental method for simulating the migration characteristics of brine-sediment in a salt cavern gas storage under the action of air pressure rise and fall includes an experimental method for simulating the migration law of brine and sediment under free sinking conditions, an experimental method for simulating the evolution law of sediment void structure under self-weight compaction, and an experimental method for simulating the secondary migration law of brine and sediment under gas injection and production.

[0063] (1) The specific implementation steps of the experimental method for simulating the migration law of brine and sediment under free sinking conditions are as follows:

[0064] 1) Preparation of experimental samples and devices: Obtain sediment particles with different particle size ranges by screening method and configure saturated brine. The current experiment requires a simulated salt cavity experimental device, a temperature control system, and a pore pressure measurement system. Connect the side wall of the pressure chamber to the base of the simulated salt cavity with bolts, connect the side wall of the simulated salt cavity to the base of the simulated salt cavity, and install the temperature control system and the pore pressure measurement system. Pour the saturated brine into an open container and control the temperature at 50.5 °C.

[0065] 2) Set multiple groups of control experiments: Set different sediment falling heights and sediment particle size ranges.

[0066] 3) Simulate the process of sediment peeling and immersion: Pour sediment particles within a certain particle size range into the simulated salt cavity at a constant speed from a preset height until the brine liquid level is 2 - 3 cm higher than the sediment surface.

[0067] 4) Simulate free settlement: Seal the open container with a cover plate, let the experimental device stand still, and allow the sediment particles to settle fully. Observe the flow pattern of the tracer sand in the closed container, take pictures to record the migration laws of the sediment particles and brine, and at the same time, record the change in the pore pressure of the sediment. After the sediment settlement is stable, take pictures to record the stratified settlement state of the sediment.

[0068] 5) Conduct control experiments and experimental summaries: Remove the cover plate of the closed container and the pore pressure measurement system, pour out the brine, take out the sediment, air-dry or dry the sediment, wash the sediment and brine remaining in the simulated salt cavity, and then pour in the brine again. Repeat steps 3 - 4 to analyze the migration laws of brine and sediment particles under different sediment particle size ranges and different falling heights.

[0069] (2) The specific implementation steps of the simulation experiment method for the evolution law of the sediment pore structure under self-weight compaction are as follows:

[0070] 1) Self-weight stacking: Continuing from step 4 of the previous experiment, continue to let it stand and stack for 3 hours. Take pictures to record the pore pressure of the sediment and the height of the brine every 30 minutes. Draw a curve graph showing the change of the pore pressure of the sediment and the height of the brine with the compaction time.

[0071] 2) Measure the change in the sediment porosity: After 3 hours, connect the gas injection system (connect the nitrogen cylinder, the first control valve, the second control valve, the buffer bottle, the first pressure gauge, the third control valve, the fourth control valve, the second pressure gauge, and the simulated salt cavity cover plate in sequence with the gas injection pipe), and measure the sediment particle porosity every 30 minutes to record the change in the sediment porosity.

[0072] 3) Conduct control experiments and experimental summaries: Change the sediment particle size range, and repeat steps 1 - 2. Analyze the migration characteristics of brine and sediment under different self-weight compaction times and different sediment particle size ranges.

[0073] (3) The specific implementation steps of the simulation experiment method for the secondary migration law of brine and sediment under gas injection and production are as follows:

[0074] 1) Set up the gas injection and production device: Continuing from step 2 of the previous experiment, connect the gas production system (connect the simulated salt cavity cover plate, the fifth control valve, and the gas storage cylinder in sequence with the exhaust pipe) to prepare for simulating the gas injection and production process.

[0075] 2) First, simulate the gas injection process: Inject gas and pressurize (0.005 - 0.2 MPa), take pictures to record the change in the sediment height, record the change in the brine level and brine temperature, and draw a curve graph showing the change of the brine level, brine temperature, and sediment pore pressure with time.

[0076] 3) Simulate the gas production process: Lower the gas production pressure (0.005 - 0.2 MPa), take photos to record the change in the height of sediment, record the change in the brine level and temperature, and plot the curves of the brine level, brine temperature, and sediment pore pressure changing with time.

[0077] 4) Measure the effective void volume of the sediment: Connect the brine drainage system, inject gas to drain the brine, and record the volume of the drained brine. This volume is the void volume in the sediment available for gas storage.

[0078] 5) Conduct control experiments and experimental summaries: Change the particle size range of the sediment, and repeat steps 1 - 4. Summarize the secondary migration laws of brine and sediment under gas injection and production.

Claims

1. An experimental device for simulating the brine-sludge migration characteristics of a salt cavern gas storage under the action of gas pressure rise and fall, characterized in that: The experimental device includes a gas injection system, a simulated salt cavity, a gas production system, a brine discharge system, a temperature control system and a pore pressure measurement system; the gas injection system and the simulated salt cavity are connected through a gas injection pipe; the gas production system and the simulated salt cavity are connected through an exhaust pipe; the simulated salt cavity and the brine discharge system are connected through a simulated brine discharge pipe and a drainage pipe; the temperature control system and the pore pressure measurement system are connected to the simulated salt cavity through pipelines.

2. The experimental device for simulating the brine-sludge migration characteristics of salt cavern gas storage under the action of gas pressure rise and fall according to claim 1, characterized in that: The gas injection system comprises a nitrogen bottle, a buffer bottle, a first control valve, a second control valve, a third control valve, a fourth control valve, a first pressure gauge, a second pressure gauge, and a gas injection pipe.

3. The device according to claim 2, characterized in that The buffer bottle is a stainless steel pressure container; the pressure gauge refers to a digital pressure gauge, which has an RS485 interface.

4. The experimental device for simulating the brine-sludge migration characteristics of salt cavern gas storage under the action of gas pressure rise and fall according to claim 1, characterized in that: The gas collection system comprises a gas collection pipe, a gas storage bottle, and a fifth control valve.

5. The experimental device for simulating the brine-sludge migration characteristics of salt cavern gas storage under the action of gas pressure rise and fall according to claim 1, characterized in that: The simulated salt chamber comprises a transparent cylindrical container, a transparent cube container or a transparent rectangular container; the transparent cylindrical container comprises a cover plate, a simulated salt chamber side wall and a simulated salt chamber base; the cover plate and the simulated salt chamber side wall are connected by a flange.

6. The device according to claim 5, characterized in that The material of the simulated salt chamber side wall is a transparent acrylic cylinder with scales on it; the cover plate is equipped with a liquid level sensor, refer to the MIK-MP ultrasonic level meter.

7. The experimental device for simulating the brine-sludge migration characteristics of salt cavern gas storage under the action of gas pressure rise and fall according to claim 1, characterized in that: The brine discharge system includes a simulated brine discharge pipe, a drain pipe, a sixth control valve, an eighth control valve, a water container, and a measuring cup; the valve is a one-way valve to prevent liquid and gas from flowing back and improve the stability and reliability of the device; the simulated brine discharge pipe and the drain pipe use stainless steel hoses.

8. The device according to claim 7, characterized in that The water container comprises a water container side wall, a water container electric heating plate, a water container base, a water container electric thermocouple, a bracket and a water container temperature control system.

9. The experimental device for simulating the brine-sludge migration characteristics of salt cavern gas storage under the action of gas pressure rise and fall according to claim 1, characterized in that: The temperature control system comprises a pressure chamber side wall, a semi-cylindrical electric heating plate of the pressure chamber, a pressure chamber thermocouple, a pressure chamber temperature controller and a water container.

10. The experimental device for simulating the brine-sludge migration characteristics of salt cavern gas storage under the action of gas pressure rise and fall according to claim 1, characterized in that: The pore pressure measurement system includes permeable stone, pore water pressure measuring hole, pore water pressure measuring tube, pore pressure sensor, data collector and result display terminal; the pore water pressure measuring tube needs to pass through a water container before connecting to the pore pressure sensor.

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