A visualized physical simulation system and method for building a salt cavern gas storage with double wells

Abstract

The application discloses a kind of salt cavern gas storage double well construction visual physical simulation system and method, belong to salt cavern underground storage construction technical field, the system it includes double well cavity forming physical simulation subsystem and double well gas injection halogen removal physical simulation subsystem;The double well cavity forming physical simulation subsystem is by water injection system, oil injection system, brine measuring system, cavity forming form monitoring system, simulation string system composition;The double well gas injection halogen removal physical simulation subsystem is by gas injection system, halogen removal system, flow field test system, simulation string system composition.The application also provides a kind of salt cavern gas storage double well construction visual physical simulation method.The technical scheme of the application carries out different salt cavern double well cavity forming process simulation using large size type salt, and real-time monitoring cavity form expansion process.The technical scheme of the application has gas injection halogen removal physical simulation experiment function, can simulate gas injection halogen removal process, and analyzes flow field movement characteristics.

Description

Technical Field

[0001] This invention relates to the field of salt cavern underground storage construction technology, and in particular to a visual physical simulation system and method for constructing a dual-well salt cavern gas storage facility. Background Technology

[0002] Underground natural gas storage facilities are the most effective and reliable means of peak shaving and storage. Salt cavern gas storage is one of the main types of gas storage facilities, with advantages such as high injection and production efficiency, large short-term throughput, low cushion gas volume, and complete recovery. Salt caverns are excellent carriers for storing natural gas and have important strategic significance in my country's West-East Gas Pipeline project.

[0003] my country faces complex geological conditions for salt cavern gas storage construction. Unlike foreign salt cavern gas storage facilities, which are built on salt domes (with salt layers 300-500m thick), domestic facilities are primarily constructed within layered salt layers. These layered salt layers in my country are characterized by poor quality (insoluble matter content 15%-35%), thin layers (60-250m), and deep burial (over 2000m in Pingdingshan and Chuzhou). These demanding geological conditions present numerous technical challenges to the drilling and completion of domestic gas storage facilities. The long cavity creation time, difficulty in controlling the cavity shape, and high cost and energy consumption of single-well salt cavern gas storage are the main factors restricting the speed and efficiency of salt cavern gas storage construction. Dual-well cavity creation is suitable for both thin and deep salt layers and is an effective way to achieve rapid dissolution and production. However, the design and control of the cavity shape are the key challenges in dual-well cavity creation, necessitating physical simulation experiments for further research.

[0004] A visualized physical simulation system for the construction of a dual-well salt cavern gas storage facility was established. Through physical simulation experiments of dual-well cavity construction, the dynamic process of cavity morphology development and changes was tested, as well as the fluid convection and diffusion distribution characteristics during cavity construction, to optimize the dual-well cavity construction process parameters. Physical simulation experiments of gas injection and brine removal during dual-well salt cavern gas storage were also conducted to evaluate the utilization rate of insoluble sediment space and to simulate the gas injection and brine removal process indoors. This system can effectively improve the efficiency of salt cavern gas storage construction and advance the construction process of salt cavern gas storage facilities in my country. Summary of the Invention

[0005] The purpose of this invention is to provide a visual physical simulation system for the construction of a dual-well salt cavern gas storage facility, which uses experiments to develop an optimized scheme for the cavity construction process parameters to guide on-site construction.

[0006] The embodiments of the present invention are implemented as follows:

[0007] On one hand, embodiments of the present invention provide a visual physical simulation system for the construction of a dual-well salt cavern gas storage facility, which includes a dual-well cavity construction physical simulation subsystem and a dual-well gas injection and brine discharge physical simulation subsystem;

[0008] The dual-well cavity-making physical simulation subsystem consists of a water injection system, an oil injection system, a brine measurement system, a cavity-making morphology monitoring system, and a simulated tubing system. The water injection system and the oil injection system are connected to the left-side simulated tubing system via pipelines, and respectively inject clean water and diesel fuel into the experimental model. The brine measurement system is connected to the right-side simulated tubing system via pipelines, and monitors the concentration and flow rate of the discharged brine. The cavity-making morphology monitoring system is connected to the lowest section of the simulated tubing system and monitors the internal morphology of the experimental model. All of the aforementioned systems—water injection, oil injection, brine measurement, cavity-making morphology monitoring, and simulated tubing—are controlled by the cavity-making control system. The cavity creation control system includes a cavity morphology monitoring and control module, a water and oil injection volume control module, an inner and outer tube position control module, and a cavity creation data acquisition module. The cavity morphology monitoring and control module is used to monitor and control the cavity morphology, the water and oil injection volume control module is used to control the water and oil injection volume, the inner and outer tube position control module is used to control the position of the inner and outer tubes, and the cavity creation data acquisition module is used to acquire cavity creation data.

[0009] The dual-well gas injection and brine discharge physical simulation subsystem consists of a gas injection system and a brine discharge system. The gas injection system is connected to the left cavity of the salt cavern model via a tubing string and functions to inject air into the model. The brine discharge system is connected to the right cavity of the model via a tubing string and functions to collect and monitor the discharged brine. Both the gas injection and brine discharge systems are controlled by a gas injection and brine discharge control system. This control system includes a pneumatic valve control module, a monitoring module, and a data acquisition module. The pneumatic valve control module controls the gas injection into the salt cavern model via pneumatic valves. The monitoring module monitors the status of the discharged brine, and the data acquisition module collects data on the discharged brine.

[0010] In a preferred embodiment of the present invention, the water injection system includes a first storage tank, a horizontal flow pump, and a pressure sensor. The clean water used in the experiment originates from the first storage tank. The horizontal flow pump and the storage tank are connected by a hose. After the horizontal flow pump is turned on, the clean water is pumped into the pipeline, passes through the pressure sensor, flows into the inner tube of the simulated tubular system on the left, and then enters the experimental model. The flow rate range of the horizontal flow pump is 0–500 ml / min, with an accuracy of 1%; the capacity of the storage tank is 50 L; and the pressure sensor range is 0–1000 kPa, with an accuracy of ±0.1%.

[0011] In the above scheme, the oil injection system includes a gas mass flow controller, a safety valve, a pneumatic valve, and a check valve. During the experiment, diesel fuel needs to be injected into the experimental model. The diesel fuel injection process is as follows: gas passes through the gas mass flow controller and the check valve into a 3L oil storage tank. The increased pressure in the storage tank forces the diesel fuel at the bottom into the injection pipeline, and then through the intermediate pipe of the simulated tubing system into the experimental model, where it floats on the water to form an oil pad.

[0012] In the above scheme, the brine measurement system includes a concentration meter and a storage tank. The brine measurement system and its accessories... Figure 1 The simulated tubing system on the right side is connected, and its main function is to collect and record the brine discharged from the experimental model. The brine in the experimental model flows through a simulated pipeline, passes through a concentration meter, and then enters the storage tank. The concentration meter measures brine concentrations up to 380 g / L with an accuracy of 0.1%.

[0013] In the above scheme, the cavity morphology monitoring system mainly consists of a laser emitter and an endoscopic probe. This part is connected to the bottom of the inner tube in the simulated tubing system, and uses infrared emission and image processing technology to scan and detect the inside of the cavity. The endoscopic probe has a diameter of 5mm and a length of 5mm.

[0014] Furthermore, the simulated tubing system includes an inner tube, a middle tube, an outer tube, and a top tubing lifting device. The bottom of the inner tube is connected to the aforementioned cavity morphology monitoring system, the middle tube is connected to the aforementioned water injection system, and the outer tube is connected to the aforementioned oil injection system. This system utilizes the top lifting device to adjust the depth of the inner, middle, and outer tubes.

[0015] Furthermore, the gas injection system includes an air compressor and a gas mass flow controller. This system is part of the dual-well gas injection and brine discharge physical simulation subsystem, and its main function is to inject gas into the salt cavern model. The air compressor draws in external air and pumps it into the pipeline, while a portion of the gas enters the salt cavern model through the gas mass flow controller. The gas mass flow controller has an operating flow rate range of 0-500 ml / min and an operating pressure of 3 MPa.

[0016] Furthermore, the brine discharge system includes a mechanically assisted pump, a buffer container, a backpressure valve, a gas flow meter, a dryer, and a level gauge. The air pumped in by the aforementioned air compressor enters the buffer container, and the mechanically assisted pump pressurizes the salt cavern model through the backpressure valve. When the internal pressure of the salt cavern model exceeds the limiting pressure of the backpressure valve, the brine and a small amount of gas inside the cavity will sequentially enter the level gauge, dryer, and gas flow meter through the backpressure valve for the collection and monitoring of the brine and discharged gas.

[0017] On the other hand, embodiments of the present invention provide a visual physical simulation method for the construction of a dual-well salt cavern gas storage facility, comprising two parts: a physical simulation experiment for dual-well cavity construction and a physical simulation experiment for gas injection and brine discharge.

[0018] The physical simulation experiment for creating a cavity in two wells includes the following steps:

[0019] 1) Connect each device according to the flowchart of the dual-well cavity physical simulation subsystem device;

[0020] 2) Check whether the valves, pressure sensors, and flow pumps are in normal working condition;

[0021] 3) To check the airtightness of the experimental setup, saturated brine was added to the storage tank. The valves, the horizontal flow pump, and all monitoring equipment were turned on. After the saturated brine passed through the pipelines and the experimental model, it flowed into the storage tank of the brine monitoring system on the right. The pumped inflow and brine outflow were compared. If they were consistent, the setup was airtight, and the next step of the experiment could proceed. If the brine outflow was less than the pumped inflow, the airtightness of each section of the pipeline was checked until the pumped inflow and brine outflow were consistent.

[0022] 4) Open pipeline valves, pressure sensors, and concentration meters as required by the experiment;

[0023] 5) Turn on the horizontal flow pump to pump the fresh water in the storage tank into the experimental model, and use a concentration meter to record the brine concentration in real time;

[0024] 6) During the experiment, adjust the height of the intermediate and outer pipes of the simulated tubular system and the diesel pumping rate according to the experimental design;

[0025] 7) After each cavity creation stage is completed, turn off the horizontal flow pump, adjust the height of the inner tube, and use the cavity morphology monitoring system to scan and record the cavity morphology of that stage.

[0026] 8) Repeat steps 5)-7) until the experiment is over.

[0027] The physical simulation experiment of gas injection and brine discharge includes the following steps:

[0028] 1) Connect each device according to the flowchart of the gas injection and brine discharge physical simulation subsystem;

[0029] 2) Check whether the air compressor, gas mass flow controller, gas flow meter, etc. are in normal working condition;

[0030] 3) To check the airtightness of the experimental apparatus, close the back pressure valve, inject a small amount of air, and observe whether there is a change in the reading of the gas mass flow controller. If there is no change in the reading, it means that the experimental apparatus is airtight and the next step of the experiment can be carried out. If the reading changes, it means that there is a gas leak. Check the airtightness of the experimental apparatus in sections.

[0031] 4) After opening the pipeline valves according to the experimental requirements, turn on the air compressor to start the experiment.

[0032] 5) During the experiment, the changes in insoluble matter during the gas injection and brine discharge process were observed using the equipment's viewing window;

[0033] 6) During the experiment, the state of the insoluble matter was recorded at regular intervals using a camera, the amount of brine discharged was recorded using a level gauge, and the amount of gas discharged was recorded using a gas flow meter.

[0034] The beneficial effects of the embodiments of the present invention are:

[0035] This invention provides a visualized physical simulation system and method for constructing a dual-well salt cavern gas storage facility. It uses a large-size salt sample (experimental model) to simulate different dual-well cavity construction processes and monitors the cavity morphology expansion process in real time. The technical solution of this invention has the function of physical simulation experiments for gas injection and brine discharge, enabling the simulation of the gas injection and brine discharge process, analysis of changes in insoluble matter at different stages, and the utilization effect of sediment pore space. Attached Figure Description

[0036] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of the present invention and should not be regarded as a limitation on the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0037] Figure 1 This is a schematic diagram of the structure of the dual-well cavity-building physical simulation subsystem in the visual physical simulation system for dual-well construction of salt cavern gas storage of the present invention;

[0038] Figure 2 This is a schematic diagram of the structure of the physical simulation subsystem for dual-well gas injection and brine discharge in the visual physical simulation system for dual-well construction of salt cavern gas storage of the present invention;

[0039] Figure 3 This is a schematic diagram of the simulated tubing system structure in the physical simulation subsystem for dual-well cavity construction. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Please refer to Figures 1-3The first embodiment of the present invention provides a visual physical simulation system for the construction of a dual-well salt cavern gas storage facility, which includes a dual-well cavity construction physical simulation subsystem and a dual-well gas injection and brine discharge physical simulation subsystem;

[0042] The dual-well cavity-making physical simulation subsystem consists of a water injection system, an oil injection system, a brine measurement system, a cavity-making morphology monitoring system, and a simulated tubing system. The water injection system and the oil injection system are connected to the left-side simulated tubing system 10 via pipelines, and respectively have the function of injecting clean water and diesel fuel into the experimental model 12. The brine measurement system is connected to the right-side simulated tubing system 11 via pipelines, and is used to monitor the concentration and flow rate of the discharged brine. The cavity-making morphology monitoring system is connected to the lowest tubing section of the simulated tubing system, and is used to monitor the internal morphology of the experimental model. The water injection system, oil injection system, brine measurement system, cavity-making morphology monitoring system, and simulated tubing system are all controlled by the cavity-making control system. The cavity-making control system can perform cavity morphology monitoring and control, water and oil injection volume control, inner and outer tubing position control, and cavity-making data acquisition.

[0043] The dual-well gas injection and brine discharge physical simulation subsystem consists of a gas injection system and a brine discharge system. The gas injection system is connected to the left cavity of the salt cavern model 20 via a tubing string, and functions to inject air into the salt cavern model 20. The brine discharge system is connected to the right cavity of the salt cavern model 20 via a tubing string, and is used to collect and monitor the discharged brine. Both the gas injection system and the brine discharge system are controlled by a gas injection and brine discharge control system. The gas injection and brine discharge control system can control the gas injection operation inside the salt cavern model by controlling pneumatic valves, and also has the function of monitoring and collecting data on the discharged brine.

[0044] The water injection system includes a first storage tank 1, a horizontal flow pump 2, and a pressure sensor 3. The clean water in the experimental model 12 comes from the first storage tank 1. The horizontal flow pump 2 and the first storage tank 1 are connected by a hose. After the horizontal flow pump 2 is turned on, the clean water is pumped into the pipeline, flows into the simulated tubular system through the pressure sensor 3, and enters the experimental model.

[0045] The oil injection system includes a gas mass flow controller 4, a safety valve 5, a pneumatic valve 6, and a check valve 7. The oil pad 8 in the experimental model 12 is formed by the gas mass flow controller 4 drawing air into the pipeline, which then passes through the check valve 7 and the safety valve 5 into the oil storage tank 9. This forces the diesel fuel in the oil storage tank 9 into the injection pipeline, where it passes through the pneumatic valve 6 before entering the experimental model to form the oil pad 8.

[0046] The brine measurement system includes a concentration meter 13 and a second storage tank 14. In the experimental model 12, the extracted brine flows into the discharge pipeline, passes through a flow meter, and then enters the second storage tank 14 to monitor the concentration and flow rate of the extracted brine.

[0047] The cavity morphology monitoring system 15 includes a laser emitter and an endoscopic probe, used to monitor the morphology inside the experimental model 12. A salt layer 28 is provided inside the experimental model 12.

[0048] like Figure 3 As shown, the simulated tubing system includes an inner tube 16, a middle tube 17, an outer tube 18, and a top tubing lifting device 19. The bottom of the inner tube 16 is connected to the cavity morphology monitoring system 15, the middle tube 17 is connected to the water injection system, and the outer tube 18 is connected to the oil injection system.

[0049] Figure 1 The intermediate storage tank is made of HDPE material, with a diameter of 415mm, a height of 575mm, an inlet diameter of 200mm, and a wall thickness of 1.5mm. Concentration measurement is achieved using an online concentration monitor with a measurement range of 0–380g / L and an operating temperature of 5–100℃. The cavity morphology monitoring system has a measurement accuracy of ±1mm. The simulated tubing system is automatically adjustable, with an automatic adjustment range of 0–50cm for both inner and outer tubing, and a positioning accuracy of ±1mm. The horizontal flow pump has a flow rate of 0–500ml / min and an accuracy of 1%. The gas mass flow controller has a working flow rate of 0–500ml / min and a working pressure of 3MPa. The oil storage tank has a volume of 3L and a pressure resistance of ≤3MPa. The simulated tubing system uses 316L material for the inner, middle, and outer tubes. The top lifting system has an adjustable length of ≥1m, a pitch of 3mm, and a motor power of 350W. The pressure sensor has a range of 0–1000KPa and an accuracy of ±0.1%. The endoscope probe has a diameter of 5mm and a length of 5mm.

[0050] The air injection system includes an air compressor line 21 and a gas mass flow controller 4. The air injected into the salt cavern model 20 is provided by the air injection system. The air compressor draws in outside air, which passes through the gas mass flow controller 4 and enters the salt cavern model.

[0051] The brine discharge system includes a mechanically assisted pump 22, a buffer container 23, a back pressure valve 24, a gas flow meter 25, a dryer 26, and a level gauge 17. The buffer container 23 is connected to the air compressor line 21, the mechanically assisted pump 22, and the back pressure valve 24 to increase the gas pressure inside the salt cavern model. The level gauge 17, the dryer 26, and the gas flow meter 25 are connected in sequence to collect and monitor the brine and gas discharged from inside the salt cavern model 20.

[0052] Figure 2 The gas mass flow controller has a flow rate of 0-1000 ml / min and a working pressure of 20 MPa; the back pressure valve has a working pressure of 20 MPa; and the mechanical booster pump has a working pressure of 20 MPa.

[0053] A visual physical simulation method for constructing a dual-well salt cavern gas storage facility is characterized by comprising two parts: a physical simulation experiment for dual-well cavity construction and a physical simulation experiment for gas injection and brine discharge.

[0054] The physical simulation experiment for creating a cavity in two wells includes the following steps:

[0055] 1) Connect each device according to the flowchart of the dual-well cavity physical simulation subsystem device;

[0056] 2) Check whether the valves, pressure sensors, and flow pumps are in normal working condition;

[0057] 3) To check the airtightness of the experimental apparatus, saturated brine was added to the storage tank, and the valves, horizontal flow pump, and monitoring equipment were turned on. After the saturated brine flowed into the storage tank through the pipeline and the salt, the pump inflow and the brine outflow were compared. If they were consistent, it indicated that the apparatus was airtight and the next experiment could be carried out. If the brine outflow was less than the pump inflow, the airtightness of each part of the pipeline was checked in sections until the pump inflow and the brine outflow were consistent.

[0058] 4) Open pipeline valves, pressure sensors, and concentration meters as required by the experiment;

[0059] 5) Turn on the horizontal flow pump to pump the freshwater from the storage tank into the auxiliary tank. Figure 1 In the experimental model, the concentration of brine was recorded in real time at the brine outlet;

[0060] 6) During the experiment, adjust the height of the inner and outer tubes of the cavity and the diesel pumping rate according to the experimental design;

[0061] 7) After each cavity creation stage is completed, turn off the advection pump, adjust the height of the inner tube, and use the cavity morphology monitoring system to scan and record the cavity morphology of that stage.

[0062] 8) Repeat steps 5)-7) until the experiment is finished;

[0063] The physical simulation experiment of gas injection and brine discharge includes the following steps:

[0064] 1) Connect each device according to the flowchart of the gas injection and brine discharge physical simulation subsystem;

[0065] 2) Check whether the air compressor, gas mass flow controller, gas flow meter, etc. are in normal working condition;

[0066] 3) To check the airtightness of the experimental apparatus, close the back pressure valve, inject a small amount of air, and observe whether there is a change in the reading of the gas mass flow controller. If there is no change in the reading, it means that the experimental apparatus is airtight and the next step of the experiment can be carried out. If the reading changes, it means that there is a gas leak. Check the airtightness of the experimental apparatus in sections.

[0067] 4) After opening the pipeline valves according to the experimental requirements, turn on the air compressor to start the experiment;

[0068] 5) During the experiment, the changes in insoluble matter 29 during the gas injection and brine discharge process were observed using the equipment's viewing window;

[0069] 6) During the experiment, the state of the insoluble matter 29 was recorded at regular intervals using a camera, the amount of brine discharged was recorded using a level gauge, and the amount of gas discharged was recorded using a gas flow meter.

[0070] It should be understood that the specific embodiments described above are merely illustrative or explanatory of the principles of the invention and do not constitute a limitation thereof. Therefore, any modifications, equivalent substitutions, improvements, etc., made without departing from the spirit and scope of the invention should be included within the protection scope of the invention. Furthermore, the appended claims are intended to cover all variations and modifications falling within the scope and boundaries of the appended claims, or equivalent forms of such scope and boundaries.

Claims

1. A visualized physical simulation system for double-well construction of a salt cavern gas storage, characterized in that, It includes a dual-well cavity creation physical simulation subsystem and a dual-well gas injection and brine discharge physical simulation subsystem; The dual-well cavity-making physical simulation subsystem consists of a water injection system, an oil injection system, a brine measurement system, a cavity-making morphology monitoring system, and a simulation tubing system. The water injection system and the oil injection system are connected to the left simulation tubing system (10) via pipelines, and respectively have the functions of injecting clean water and diesel fuel into the experimental model (12). The brine measurement system is connected to the right simulation tubing system (11) via pipelines and is used to monitor the concentration and flow rate of the discharged brine. The cavity-making morphology monitoring system is connected to the lowest tubing section of the simulation tubing system and is used to monitor the internal morphology of the experimental model. The aforementioned water injection system, oil injection system, brine measurement system, cavity morphology monitoring system, and simulated tubing system are all controlled by a cavity creation control system. This cavity creation control system includes a cavity morphology monitoring and control module, a water and oil injection volume control module, an inner and outer tube position control module, and a cavity creation data acquisition module. The cavity morphology monitoring and control module monitors and controls the cavity morphology; the water and oil injection volume control module controls the water and oil injection volumes; the inner and outer tube position control module controls the inner and outer tube positions; and the cavity creation data acquisition module acquires cavity creation data. The dual-well gas injection and brine discharge physical simulation subsystem consists of a gas injection system and a brine discharge system. The gas injection system is connected to the left cavity of the salt cavern model (20) via a tubing string and has the function of injecting air into the salt cavern model (20). The brine discharge system is connected to the right cavity of the salt cavern model (20) via a tubing string. The brine discharge system is used to collect and monitor the discharged brine. Both the gas injection system and the brine discharge system are controlled by the gas injection and brine discharge control system. The gas injection and brine discharge control system includes a pneumatic valve control module, a monitoring module, and a data acquisition module. The pneumatic valve control module is used to control the pneumatic valve to perform gas injection inside the salt cavern model. The monitoring module is used to monitor the status of the discharged brine. The data acquisition module is used to collect data on the discharged brine. The cavity morphology monitoring system (15) includes a laser emitter and an endoscope probe, used to monitor the morphology inside the experimental model (12).

2. The visualized physical simulation system for double-well construction of a salt cavern gas storage according to claim 1, characterized in that, The water injection system includes a first storage tank (1), a horizontal flow pump (2), and a pressure sensor (3). The clean water in the experimental model (12) comes from the first storage tank (1). The horizontal flow pump (2) and the first storage tank (1) are connected by a hose. After the horizontal flow pump (2) is turned on, the clean water is pumped into the pipeline, flows into the simulated tubular system through the pressure sensor (3), and enters the experimental model.

3. The visual physical simulation system for dual-well construction of a salt cavern gas storage facility according to claim 2, characterized in that, The oil injection system includes a gas mass flow controller (4), a safety valve (5), a pneumatic valve (6), and a check valve (7). The oil pad (8) in the experimental model (12) is formed by the gas mass flow controller (4) drawing air into the pipeline and then through the check valve (7) and the safety valve (5) into the oil storage tank (9), which presses the diesel fuel in the oil storage tank (9) into the injection pipeline. The diesel fuel then passes through the pneumatic valve (6) and enters the experimental model to form the oil pad (8).

4. The visual physical simulation system for dual-well construction of a salt cavern gas storage facility according to claim 3, characterized in that, The brine measurement system includes a concentration meter (13) and a second storage tank (14). The extracted brine in the experimental model (12) flows into the discharge pipeline and enters the second storage tank (14) after passing through a flow meter, thereby monitoring the concentration and flow rate of the extracted brine.

5. The visual physical simulation system for dual-well construction of a salt cavern gas storage facility according to claim 4, characterized in that, The simulated tubing system includes an inner tube (16), a middle tube (17), an outer tube (18), and a top tubing lifting device (19). The bottom of the inner tube (16) is connected to the cavity morphology monitoring system (15), the middle tube (17) is connected to the water injection system, and the outer tube (18) is connected to the oil injection system.

6. The visual physical simulation system for dual-well construction of a salt cavern gas storage facility according to claim 5, characterized in that, The air injection system includes an air compressor pipeline (21) and a gas mass flow controller (4); the air injected into the salt cavern model (20) is provided by the air injection system; the air compressor draws in outside air and enters the salt cavern model through the gas mass flow controller (4).

7. A visual physical simulation system for dual-well construction of a salt cavern gas storage facility according to claim 6, characterized in that... The brine discharge system includes a mechanically assisted pump (22), a buffer container (23), a back pressure valve (24), a gas flow meter (25), a dryer (26), and a level gauge (27). The buffer container (23) is connected to the air compressor line (21), the mechanically assisted pump (22), and the back pressure valve (24) to increase the gas pressure inside the salt cavern model. The level gauge (27), the dryer (26), and the gas flow meter (25) are connected in sequence to collect and monitor the brine and gas discharged from inside the salt cavern model (20).

8. A visual physical simulation method for constructing a dual-well salt cavern gas storage facility, applied to the visual physical simulation system for constructing a dual-well salt cavern gas storage facility as described in claim 7, characterized in that, It includes two parts: physical simulation experiment of dual-well cavity construction and physical simulation experiment of gas injection and brine discharge; The physical simulation experiment for creating a cavity in two wells includes the following steps: 1) Connect each device according to the flowchart of the dual-well cavity physical simulation subsystem device; 2) Check whether the valves, pressure sensors, and flow pumps are in normal working condition; 3) To check the airtightness of the experimental apparatus, saturated brine was added to the storage tank, and the valves, horizontal flow pump, and monitoring equipment were turned on. After the saturated brine flowed into the storage tank through the pipeline and the salt, the pump inflow and the brine outflow were compared. If they were consistent, it indicated that the apparatus was airtight and the next experiment could be carried out. If the brine outflow was less than the pump inflow, the airtightness of each part of the pipeline was checked in sections until the pump inflow and the brine outflow were consistent. 4) Open pipeline valves, pressure sensors, and concentration meters as required by the experiment; 5) Turn on the horizontal flow pump to pump the fresh water in the storage tank into the experimental model, and record the brine concentration in real time at the brine outlet; 6) During the experiment, adjust the height of the inner and outer tubes of the cavity and the diesel pumping rate according to the experimental design; 7) After each cavity creation stage is completed, turn off the advection pump, adjust the height of the inner tube, and use the cavity morphology monitoring system to scan and record the cavity morphology of that stage. 8) Repeat steps 5)-7) until the experiment is finished; The physical simulation experiment of gas injection and brine discharge includes the following steps: 1) Connect each device according to the physical simulation subsystem of gas injection and brine discharge; 2) Check whether the air compressor, gas mass flow controller, and gas flow meter are in normal working condition; 3) To check the airtightness of the experimental apparatus, close the back pressure valve, inject a small amount of air, and observe whether there is a change in the reading of the gas mass flow controller. If there is no change in the reading, it means that the experimental apparatus is airtight and the next step of the experiment can be carried out. If the reading changes, it means that there is a gas leak. Check the airtightness of the experimental apparatus in sections. 4) After opening the pipeline valves according to the experimental requirements, turn on the air compressor to start the experiment; 5) During the experiment, the changes in insoluble matter during the gas injection and brine discharge process were observed using the equipment's viewing window; 6) During the experiment, the state of the insoluble matter was recorded at regular intervals using a camera, the amount of brine discharged was recorded using a level gauge, and the amount of gas discharged was recorded using a gas flow meter.

Images