A salt cavern sediment gap energy storage simulation experiment system and experiment method

Abstract

The application discloses a salt cave sediment gap energy storage simulation experiment system and experiment method, which comprises a salt cavity simulation system, a gas phase injection system and a liquid phase injection system. The gas phase injection system is used for injecting constant flow or constant pressure gas into the salt cavity simulation system to simulate a gas injection and halogen discharge process. The liquid phase injection system is used for injecting constant flow or constant pressure liquid into the salt cavity simulation system to simulate a halogen injection and gas discharge process. The salt cavity simulation system comprises a single-well vertical cavity simulation system and a double-well horizontal cavity simulation system. The single-well vertical cavity simulation system is used for simulating the change of a gas-liquid interface and a sediment state in a high-pressure gas injection and halogen discharge process. The double-well horizontal cavity simulation system is used for simulating the change of a gas-liquid interface and a sediment state in a low-pressure gas injection and halogen discharge process. The application solves the real-time monitoring of a halogen discharge pressure, flow and sediment migration state in a gas injection and halogen discharge process in the sediment, and fills the blank of the simulation of the gas injection and halogen discharge process in the sediment gap.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of salt cavern energy storage, in particular to a salt cavern sedimentation gap energy storage simulation experiment system and experiment method. BACKGROUND

[0002] Salt rock has low permeability, good rheological properties and damage self-recovery characteristics, and is internationally recognized as an ideal medium for energy storage. Most foreign salt cavern gas storage is built in high-purity, thick salt dome type salt rock formed by marine deposition, while all Chinese salt cavern gas storage is built in stratified salt rock strata formed by terrestrial deposition.

[0003] Stratified salt layer has the characteristics of small salt rock thickness, many interlayers and high insoluble impurity content. The cavity formed after water-soluble cavity formation is buried by a large amount of insoluble sediment, resulting in small effective volume of the storage. Using sediment gap gas storage to solve the problem of small effective gas storage volume of high-impurity salt mine and poor economic efficiency of building a storage significantly increases the capacity of salt cavern gas storage.

[0004] Currently, salt cavern gas storage mainly has two cavity forming methods: double-well horizontal cavity and single-well vertical cavity. The salt cavity formed is full of brine, which must be discharged by gas injection and brine discharge to realize the gas storage function of the cavity. Double-well horizontal cavity can be used to rebuild sediment type salt cavern gas storage by "two injection and one discharge" gas injection and brine discharge, and single-well vertical cavity can be used to rebuild sediment type salt cavern gas storage by "one injection and one discharge" gas injection and brine discharge. To use sediment gap gas storage, the brine in the sediment gap must be discharged, and "low-level brine discharge" is used in the sediment body. During the gas injection and brine discharge process, the discharge pressure, flow rate and backwashing time will change with the sediment accumulation state, discharge depth and pipe string crystallization, but there is currently no simulation experiment system and experiment method for gas injection and brine discharge in the sediment. SUMMARY

[0005] To solve the above problems, the present application provides a salt cavern sedimentation gap energy storage simulation experiment system and experiment method to solve the real-time monitoring experiment system of the discharge pressure, flow rate and sediment migration state during the gas injection and brine discharge process in the sediment. The technical solution is as follows:

[0006] The first aspect of the application provides a salt cavern sediment gap energy storage simulation experiment system, comprising a salt cavity simulation system, a gas phase injection system and a liquid phase injection system, the gas phase injection system is used for injecting constant flow or constant pressure gas into the salt cavity simulation system to simulate the gas injection and halogen displacement process, the liquid phase injection system is used for injecting constant flow or constant pressure liquid into the salt cavity simulation system to simulate the halogen injection and gas displacement process, the salt cavity simulation system comprises a single well vertical cavity simulation system and a double well horizontal cavity simulation system, the single well vertical cavity simulation system is used for simulating the change of gas-liquid interface and sediment state in the high-pressure gas injection and halogen displacement process, and the double well horizontal cavity simulation system is used for simulating the change of gas-liquid interface and sediment state in the low-pressure gas injection and halogen displacement process.

[0007] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by an embodiment, the single well vertical cavity simulation system comprises a high-pressure cavity and a first halogen displacement pipe connected with the high-pressure cavity through a variable-diameter pipe, the diameter of the variable-diameter pipe gradually decreases along the direction from the high-pressure cavity to the first halogen displacement pipe, the variable-diameter pipe is used for simulating the sediment particle sand plug state, a back pressure valve is arranged on the outlet pipeline of the first halogen displacement pipe and the inlet pipeline of the high-pressure cavity respectively, and the halogen displacement speed is slowed down by slowly reducing the pressure through the back pressure valve.

[0008] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by an embodiment, the double well horizontal cavity simulation system comprises two low-pressure cavities connected through a communication pipeline, the communication pipeline connects a second halogen displacement pipe, and a back pressure valve is arranged on the outlet pipeline of the second halogen displacement pipe and the inlet pipeline of the two low-pressure cavities respectively, and the halogen displacement speed is slowed down by slowly reducing the pressure through the back pressure valve.

[0009] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by an embodiment, the gas phase injection system comprises a gas-liquid separation tank and a gas phase gas injection and halogen displacement pipeline and a gas phase halogen injection and gas displacement pipeline connected with the gas-liquid separation tank in parallel respectively, a gas cylinder, a first gas flow controller and a gas pressure reducing valve connected in parallel are arranged on the gas phase gas injection and halogen displacement pipeline, and a second gas flow controller and a vent pipeline connected with the second gas flow controller are arranged on the gas phase halogen injection and gas displacement pipeline.

[0010] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by an embodiment, the liquid phase injection system comprises a water storage tank and a liquid phase gas injection and halogen displacement pipeline and a liquid phase halogen injection and gas displacement pipeline connected with the water storage tank in parallel respectively, a first liquid flow meter and a turbidity meter are arranged on the liquid phase gas injection and halogen displacement pipeline, and a plunger pump connected with the water storage tank, a PLC frequency converter and a second liquid flow meter are arranged on the liquid phase halogen injection and gas displacement pipeline.

[0011] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by one embodiment, the low-pressure chamber is at least partially transparent, and the communication pipeline is a transparent pipeline, and a plurality of view windows are arranged on the high-pressure chamber in the depth direction.

[0012] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by one embodiment, the single-well vertical chamber simulation system and the double-well horizontal chamber simulation system further comprise a high-speed camera for observing the gas-liquid interface depth and the sediment particle migration state in real time.

[0013] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by one embodiment, a brine pore pressure sensor is arranged on the low-pressure chamber in the depth direction to monitor the brine pore pressure in the sediment.

[0014] For example, in the salt cavern sediment gap energy storage simulation experiment system provided by one embodiment, a pressure gauge is arranged on the high-pressure chamber and the low-pressure chamber inlet pipeline to monitor the injected gas pressure in real time, and a pressure gauge is arranged on the first brine discharge pipeline and the second brine discharge pipeline outlet pipeline to monitor the discharged brine pressure in real time.

[0015] The second aspect of the present application provides a salt cavern sediment gap energy storage simulation experiment method, which uses the above-mentioned salt cavern sediment gap energy storage simulation experiment system, and comprises the following steps:

[0016] S1, preparing a high-impurity salt mine sediment sample; controlling the sediment particle gradation, and layering the sediment particles to the high-pressure chamber or the low-pressure chamber;

[0017] S2, starting the liquid phase injection system to fill the high-pressure chamber or the low-pressure chamber with saturated brine, so that the saturated brine can flow out through the gas-liquid separation tank;

[0018] S3, starting the high-speed camera, setting the picture capture parameters; setting the upper limit range of the experimental pressure and the data recording frequency of the monitoring instrument;

[0019] S4, starting the gas phase injection system to inject nitrogen into the high-pressure chamber or the low-pressure chamber in a constant flow or constant pressure mode, discharging the brine to the liquid storage tank, and performing the gas injection and brine discharge simulation experiment in the sediment;

[0020] S5, starting the liquid phase injection system to inject brine into the high-pressure chamber or the low-pressure chamber in a constant flow or constant pressure mode, discharging the gas, and performing the brine injection and gas discharge simulation experiment in the sediment;

[0021] S6, closing the gas inlet switch and the brine inlet switch, opening the vent valve and the brine discharge switch, and depressurizing the high-pressure chamber and the low-pressure chamber to discharge the sediment and prepare for the next experiment process.

[0022] The S4 and S5 can be circulated and reciprocated to simulate the gas injection and brine discharge process and the brine injection and gas discharge process, respectively.

[0023] The salt cavern sediment void energy storage simulation experiment system and experiment method provided by some embodiments of the present application have the beneficial effects that the "one injection and one discharge" single-well vertical cavity simulation system and the "two injections and one discharge" double-well horizontal cavity simulation system cover the two cavity forms of the double-well horizontal cavity and the single-well vertical cavity commonly used in the salt cavern gas storage at present, and can simulate the whole process of gas injection and halogen discharge in the sediment for the salt cavity with a large amount of sediment accumulation, whether it is a horizontal cavity or a vertical cavity. In the research on the high-impurity salt cavern sediment void energy storage technology, the indoor simulation test is carried out for the two modes of gas injection and halogen discharge in the sediment void, which fills the blank of the simulation of the gas injection and halogen discharge process in the sediment void at present. The constant pressure and constant flow control modes can be realized in the gas injection and halogen discharge process, and the two circulation processes of gas injection and halogen discharge and halogen injection and gas discharge can be dynamically switched, and the carrying and plugging of the simulated flowing brine to the sediment particles are also realized. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present specification or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and those skilled in the art can obtain other drawings according to these drawings without creative labor.

[0025] Figure 1 It is a structural schematic diagram of the salt cavern sediment void energy storage simulation experiment system of the present application.

[0026] Figure 2 It is a flowchart of the salt cavern sediment void energy storage simulation experiment method of the present application. DETAILED DESCRIPTION

[0027] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are within the scope of protection of the present application.

[0028] Unless otherwise defined, technical terms or scientific terms used in the present disclosure shall have the meanings as understood by one of ordinary skill in the art to which the present disclosure pertains. The terms "first", "second", and similar terms are used herein to distinguish one element from another, but do not necessarily indicate an order of importance, a number or one of importance, or a number. The terms "include", "contain", and similar terms mean that the elements or objects before the terms encompass the elements or objects listed after the terms and their equivalents, and do not exclude other elements or objects. The terms "connect" or "connected" or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms "upper", "lower", "left", "right", and the like are used only to indicate relative positional relationships, and when the absolute positions of the described objects are changed, the relative positional relationships can also be changed accordingly.

[0029] The first aspect of the present application provides a salt cavern sediment gap energy storage simulation experiment system, as shown in Figure 1 The salt cavern simulation system 100, the gas phase injection system 200, and the liquid phase injection system 300 are provided. The gas phase injection system 200 is used to inject a constant flow or constant pressure gas into the salt cavern simulation system 100. The liquid phase injection system 300 is used to inject a constant flow or constant pressure liquid into the salt cavern simulation system 100. The salt cavern simulation system 100 includes a single-well vertical cavity simulation system 110 and a double-well horizontal cavity simulation system 120. The single-well vertical cavity simulation system 110 is used to simulate the changes of the gas-liquid interface and the sediment state during the high-pressure gas injection and halogen discharge or halogen injection and gas discharge process. The double-well horizontal cavity simulation system 120 is used to simulate the changes of the gas-liquid interface and the sediment state during the low-pressure gas injection and halogen discharge or halogen injection and gas discharge process.

[0030] The single-well vertical cavity simulation system 110 is "one injection and one discharge", and the double-well horizontal cavity simulation system 120 is "two injections and one discharge". It covers the two cavity forms of the commonly used double-well horizontal cavity and single-well vertical cavity of the salt cavern gas storage. For a salt cavity with a large amount of sediment accumulation, whether it is a horizontal cavity or a vertical cavity, the simulation of the entire process of gas injection and halogen discharge in the sediment gap can be realized.

[0031] The present application provides a systematic experimental system for indoor simulation test of the two ways of gas injection and halogen discharge and halogen injection and gas discharge in the sediment gap in the research of high-impurity salt cavern sediment gap energy storage technology, which fills the gap of the simulation of the gas injection and halogen discharge process in the sediment gap.

[0032] For example, in one embodiment of the salt cavern sediment gap energy storage simulation experiment system, as shown in Figure 1As shown, the single-well vertical cavity simulation system 110 includes a high-pressure cavity 111 and a first brine discharge pipe 113 connected to the high-pressure cavity 111 through a variable-diameter pipe 112, the diameter of the variable-diameter pipe 112 gradually decreases along the direction from the high-pressure cavity 111 to the first brine discharge pipe 113, the variable-diameter pipe 112 is used to simulate the sand plug state of the sediment particles, a back pressure valve P5 is arranged at the outlet pipeline of the first brine discharge pipe 113, a back pressure valve P4 is arranged on the inlet pipeline of the high-pressure cavity 111, the slow pressure reduction through the back pressure valve achieves the slow discharge of the brine, and a safety valve 114 is further arranged on the inlet pipeline of the high-pressure cavity 111.

[0033] Specifically, the variable-diameter pipe 112 is arranged along the horizontal direction, one end is connected to the bottom of the high-pressure cavity 111, and the first brine discharge pipe 113 is arranged along the vertical direction.

[0034] According to the above embodiment, in the "one injection and one discharge" system, the high-pressure cavity 111 is used to simulate the change of the gas-liquid interface and the sediment state in the high-pressure gas injection and brine discharge process, the back pressure valve achieves the slow discharge of the brine through slow pressure reduction, and the actual high-pressure state of the brine in the salt cavity is simulated; during the experiment, the sediment particles are layered filled in the high-pressure cavity 111, the interstitial space of the particles is filled with brine, the pressure gauge on the inlet pipeline of the high-pressure cavity 111 monitors the pressure of the injected gas in real time, and the pressure gauge on the outlet pipeline of the first brine discharge pipe 113 monitors the pressure of the discharged brine in real time. Three windows 115 are arranged on the high-pressure cavity 111 along the depth direction, a high-speed camera is used to observe the migration of the sediment particles in the high-pressure cavity 111. The variable-diameter pipe 112 is used to simulate the sand plug state of the sediment particles, the cross-sectional area of the variable-diameter pipe 112 gradually decreases to increase the brine discharge flow rate, and the bottom sediment particles are carried to simulate the particle migration and plugging phenomenon. The occurrence of the sand plug of the sediment particles is reflected by the increase of the pressure of the injected gas, and the starting flow rate of the sediment particles is analyzed by monitoring the flow rate of the discharged brine.

[0035] For example, in the salt cavern sediment interstitial space energy storage simulation experiment system provided by one embodiment, as shown in Figure 1 As shown, the double-well horizontal cavity simulation system 120 includes two low-pressure cavities 122 connected through a communication pipeline 121, the communication pipeline 121 is connected to a second brine discharge pipe 123, back pressure valves are arranged on the outlet pipeline of the second brine discharge pipe 123 and the inlet pipelines of the two low-pressure cavities 122 respectively, and the slow pressure reduction through the back pressure valves achieves the slow discharge of the brine.

[0036] Specifically, a back pressure valve P3 is arranged on the outlet pipeline of the second brine discharge pipe 123, back pressure valves P1 and P2 are respectively arranged on the inlet pipelines of the two low-pressure cavities 122, the communication pipeline 121 is arranged along the horizontal direction, and two ends are respectively connected to the bottoms of the low-pressure cavities 122. The second brine discharge pipe 123 is connected to the middle part of the communication pipeline 121 and is arranged along the vertical direction.

[0037] According to the above embodiment, the "two-injection and one-discharge" simulation system realizes the synchronous reduction of the gas-liquid interface in the two low-pressure chambers 122 by injecting isobaric gas through the left and right low-pressure chambers 122, and the brine in the two low-pressure chambers 122 is discharged through the shared second brine discharge pipe 123, and the low-pressure chambers 122 are used to simulate the changes of the gas-liquid interface and the sediment state during the low-pressure gas injection and brine discharge process. During the experiment, the low-pressure chambers 122 are respectively filled with sediment particles, and the interstitial space of the particles is filled with brine. The pressure gauge on the inlet pipeline of the low-pressure chamber 122 monitors the pressure of the injected gas in real time, and the pressure gauge on the outlet pipeline of the second brine discharge pipe 123 monitors the pressure of the discharged brine in real time.

[0038] The low-pressure chamber 122 and the communication pipeline 121 are made of transparent material, and the depth of the gas-liquid interface and the migration state of the sediment particles can be observed in real time by using a high-speed camera.

[0039] For example, in the salt cavern sediment interstitial space energy storage simulation experiment system provided by an embodiment, as shown in Figure 1 The gas phase injection system 200 includes a gas-liquid separation tank 210 and gas phase injection and brine discharge pipelines 220 and 230 connected in parallel with the gas-liquid separation tank 210, respectively. The gas phase injection and brine discharge pipeline 220 is provided with a gas cylinder 221 and a first gas flow controller 222 and a gas pressure reducing valve 223 connected in parallel, and the gas phase injection and brine discharge pipeline 230 is provided with a second gas flow controller 231 and a vent pipeline 232 connected with the second gas flow controller 231.

[0040] The gas cylinder 221 stores high-pressure nitrogen gas.

[0041] According to the above embodiment, the nitrogen gas cylinder 221 provides pure high-pressure nitrogen gas for gas injection. The gas flow controller controls the injection of nitrogen gas into the high-pressure chamber 111 or the low-pressure chamber 122 at a given flow rate, and the gas pressure reducing valve 223 controls the injection of nitrogen gas into the high-pressure chamber 111 or the low-pressure chamber 122 at a given pressure. The gas-liquid separation tank 210 separates the liquid in the injected nitrogen gas or separates the liquid in the vented nitrogen gas to prevent affecting the monitoring accuracy of the physical simulation system.

[0042] For example, in the salt cavern sediment interstitial space energy storage simulation experiment system provided by an embodiment, as shown in Figure 1 The liquid phase injection system 300 includes a water storage tank 310 and liquid phase injection and brine discharge pipelines 320 and 330 connected in parallel with the water storage tank 310, respectively. The liquid phase injection and brine discharge pipeline 320 is provided with a first liquid flowmeter 321 and a turbidimeter 322, and the liquid phase injection and brine discharge pipeline 330 is provided with a plunger pump 331 connected with the water storage tank 310, a PLC frequency converter 332 and a second liquid flowmeter 333.

[0043] The first liquid flow meter 321 and the second liquid flow meter 333 are clamp-on flow meters.

[0044] According to the above embodiment, the high-precision metering plunger pump 331 provides high-pressure brine in the brine injection and gas discharge process, and provides brine with constant flow by cooperating with the liquid flow meter and the PLC frequency converter 332; the PLC frequency converter 332 is used to collect the flow value of the liquid flow meter in real time, and control the pumping rate of the high-precision metering plunger pump 331; the turbidimeter 322 is used to measure the turbidity value of the discharged brine in real time, and collect the particle concentration value, which is used to calculate the mass of the sediment particles carried by the brine; and the gas flow meter is used to monitor the flow value of the discharged gas in the brine injection and gas discharge process.

[0045] The salt cavern sediment void energy storage simulation experiment system provided by the present application can realize two control modes of constant pressure and constant flow in the gas injection and brine discharge process through the gas phase injection system 200 and the liquid phase injection system 300, and can dynamically switch the two circulation processes of gas injection and brine discharge and brine injection and gas discharge. The constant pressure control mode of the gas injection process is realized through the pressure reducing valve 223, and the constant flow control mode is realized through the gas flow controller; the constant pressure control mode of the brine injection process is realized through the back pressure valve, and the constant flow control mode is realized through the PLC frequency converter 332; the carrying and plugging phenomena of the brine to the sediment particles in the simulation flow are realized, the high-speed camera is used to observe the sediment particle migration state in the high-pressure and low-pressure chambers, the horizontal variable-diameter pipeline 112 is used to simulate the horizontal salt cavern sediment particle plugging, and the turbidimeter 322 is used to measure the sediment particle concentration value in the brine in real time.

[0046] For example, in the salt cavern sediment void energy storage simulation experiment system provided by one embodiment, the brine pore pressure sensor is arranged along the depth direction of the low-pressure chamber 122 to monitor the brine pore pressure in the sediment.

[0047] The second aspect of the present application provides a salt cavern sediment void energy storage simulation experiment method, which is carried out by using the above-mentioned salt cavern sediment void energy storage simulation experiment system, as shown in Figure 2 The method comprises the following steps:

[0048] S1: Prepare a high-impurity salt mine sediment sample; control the sediment particle gradation, and layer the sediment particles to the high-pressure chamber 111 or the low-pressure chamber 122, specifically:

[0049] For the "one injection and one row" high-pressure chamber 111, open the chamber top cover, and according to the average particle size of the sediment particles from small to large, layer the sediment particles into the high-pressure chamber 111 until the sediment is stacked to 1 / 2-2 / 3 of the total height of the high-pressure chamber 111; install different transition size reducing pipes 112 (for example, the pipe diameter transition sizes are DN100-DN100, DN100-DN50, and DN100-DN25) to simulate the sediment particle plugging phenomenon in the horizontal reducing pipe 112;

[0050] For the "two injections and one row" two symmetrical low-pressure chambers 122, open the top covers of the two chambers, and according to the average particle size of the sediment particles from small to large, layer the sediment particles into the chambers respectively until the sediment is stacked to 1 / 2-2 / 3 of the total height of the chambers; fill the screen cylinder in the horizontal communication pipeline 121 with sediment particles, and then install it into the horizontal communication pipeline 121 to simulate the sediment accumulation particles in the horizontal chamber;

[0051] S2 starts the liquid phase injection system 300 to fill the high-pressure chamber 111 or the low-pressure chamber 112 with saturated brine, so that the saturated brine can flow out through the gas-liquid separation tank 210. Specifically:

[0052] For the "one injection and one row" high-pressure chamber 111, by default, all valves are in the closed state, open HQ04, HQ03, QD07, QD08, and ZF04, start the high-precision plunger pump 331, and pump the brine into the high-pressure chamber 111 until the high-pressure chamber 111 and the first row of brine pipes 113 are completely filled with brine, and the brine can flow out through the gas-liquid separation tank 210;

[0053] For the "two injections and one row" two symmetrical low-pressure chambers 122, open HQ04, HQ02, QD05, QD06, QD08, and ZF04, start the high-precision plunger pump 331, and pump the brine into the low-pressure chamber 122 until the low-pressure chamber 122 and the second row of brine pipes 123 are completely filled with brine, and the brine can flow out through the gas-liquid separation tank 210;

[0054] S3 starts the high-speed camera, so that the high-speed camera is directly opposite the opening window 115 of the high-pressure chamber 111 and the transparent low-pressure chamber 122 and the communication pipeline 121, sets the picture capture parameters, prepares the high-speed camera picture dynamic capture function, and completes the preparation work of the high-speed camera; sets the upper limit range of the experimental pressure of the monitoring instrument and the data recording frequency. Specifically:

[0055] For the "one injection one row" high pressure chamber 111, the back pressure valve P5 pressure is set to the target setting value 10 MPa. Or for the "two injections one row" low pressure chamber 122, the back pressure valve P3 pressure is set to the target setting value 0.8 MPa. For other pressure gauges P1, P3, P4, the data sampling frequency is set to 1 second or 2 seconds; for the first gas flow controller 222, the second gas flow controller 231, the first liquid flow meter 321, the second liquid flow meter 333 and the gas pressure reducing valve 223, the data sampling frequency is set to 1 second or 2 seconds; for the turbidimeter 322, the data sampling frequency is set to 1 second, and the preparation work of various monitoring instruments is completed;

[0056] S4 start the gas injection system, inject nitrogen into the high pressure chamber 111 or the low pressure chamber 122 in constant flow or constant pressure mode, discharge the brine to the liquid storage tank 310, and carry out the gas injection and brine discharge simulation experiment in the sediment, specifically:

[0057] Slowly open the switch K1 of the nitrogen gas cylinder 221, inject nitrogen into the high pressure or low pressure chamber in constant flow or constant pressure mode; in constant flow mode, open QD01 and QD02 to control the gas flow through the first gas flow controller 222; in constant pressure mode, open QD03 and QD04 to control the gas pressure through the gas pressure reducing valve 223. Then, the gas passes through the gas-liquid separation tank 210 to discharge the liquid that may be carried by the gas, and the gas enters the two injection one row two symmetrical low pressure chambers 122 or the one injection one row high pressure chamber 111;

[0058] If the simulation experiment of the two injection one row horizontal chamber is carried out, close the switch QD07, open the switches QD05 and QD06, and the gas is injected into the two low pressure chambers 122. The two low pressure chambers 122 are in communication, the gas pressure in the chambers is equal, and after the pressure in the low pressure chamber reaches the set pressure value 0.8 MPa, the back pressure valve P3 automatically opens. The brine in the chamber is pushed by the gas pressure, passes through the second brine discharge pipe 123, the switches HQ02 and HQ05, and the first liquid flow meter 321, and enters the water storage tank 310;

[0059] If the simulation experiment of the one injection one row vertical chamber is carried out, close the switches QD05 and QD06, open the switch QD07, and the gas is injected into the high pressure chamber 111. After the pressure in the high pressure chamber 111 reaches the set pressure value 10 MPa, the back pressure valve P5 automatically opens. The brine in the chamber is pushed by the gas pressure, passes through the first brine discharge pipe 113, the switches HQ03 and HQ05, and the first liquid flow meter 321, and enters the water storage tank 310;

[0060] S5 first stops the S4, closes the intake switch QD01, QD02 or QD03, QD04, closes the brine exhaust switch HQ05, starts the liquid phase injection system, injects brine into the high-pressure chamber 111 or the low-pressure chamber 122 in a constant flow or constant pressure mode, exhausts the gas, and performs a simulation experiment of injecting brine and exhausting gas in the sediment, specifically:

[0061] If a simulation experiment of injecting brine and exhausting gas in a two-injection-one-exhaust horizontal chamber is performed, the switches HQ04 and HQ08 are opened. The high-precision plunger pump 331 is started to inject brine into the first brine exhaust pipe 113. After the brine pressure reaches the target pressure value set by the needle valve ZF04, the gas passes through the second gas flow controller 231 and then enters the venting pipeline 232 for venting.

[0062] If a simulation experiment of injecting brine and exhausting gas in a one-injection-one-exhaust vertical chamber is performed, the switches HQ04 and HQ08 are opened. The high-precision plunger pump 331 is started to inject brine into the second brine exhaust pipe 123. After the brine pressure reaches the target pressure value set by the needle valve ZF04, the gas passes through the second gas flow controller 231 and then enters the venting pipeline 232 for venting.

[0063] The S4 and S5 can be circulated repeatedly. By performing the switch operation functions in steps S4 and S5, the simulation experiment process of injecting brine and exhausting gas and injecting gas and exhausting brine can be circulated.

[0064] S6 closes the intake switch and the brine injection switch, opens the venting valve and the brine exhaust switch, depressurizes the high-pressure chamber and the low-pressure chamber, and exhausts the sediment to prepare for the next experiment process. Specifically, after the experiment is completed, the intake switch QD01, QD02 or QD03, QD04 is closed, the brine exhaust switch HQ05 is closed, the exhaust needle valve ZF04 is opened, the gas in the chamber is discharged, the brine exhaust switch LQ01, LQ02 or HQ01 is opened, the remaining brine at the bottom of the two-injection-one-exhaust or one-injection-one-exhaust chamber is exhausted, the top cover of the two-injection-one-exhaust or one-injection-one-exhaust chamber is opened to replace different sediment particles, and the sample is refilled for the experiment.

[0065] All data during the experiment process are recorded by the monitoring instrument. The data during the experiment process can be exported and processed in other drawing software. The high-speed camera is turned off, the collected pictures are exported and imported into the image processing software for image processing. The experiment is completed. Although the embodiments of the present application have been disclosed as above, they are not limited to the application listed in the specification and the embodiments, and can be fully applied to various fields suitable for the present application. Those skilled in the art can easily make other modifications, and therefore the present application is not limited to specific details and the figures shown and described herein, without departing from the general concept defined by the claims and the equivalent scope.

Claims

1. A simulation experiment system for salt caverns with sediment voids for energy storage, characterized in that, The system comprises a salt cavity simulation system, a gas phase injection system and a liquid phase injection system, the gas phase injection system is used for injecting constant flow or constant pressure gas into the salt cavity simulation system, the liquid phase injection system is used for injecting constant flow or constant pressure liquid into the salt cavity simulation system, the salt cavity simulation system comprises a single-well vertical cavity simulation system and a double-well horizontal cavity simulation system, the single-well vertical cavity simulation system is used for simulating the change of the gas-liquid interface and the sediment state in the high-pressure gas injection and brine discharge or the brine injection and gas discharge process, and the double-well horizontal cavity simulation system is used for simulating the change of the gas-liquid interface and the sediment state in the low-pressure gas injection and brine discharge or the brine injection and gas discharge process; The single-well vertical cavity simulation system comprises a high-pressure cavity and a first brine discharge pipe connected with the high-pressure cavity through a variable-diameter pipe, the pipe diameter of the variable-diameter pipe gradually decreases along the direction from the high-pressure cavity to the first brine discharge pipe, and the variable-diameter pipe is used for simulating the sand plug state of the sediment particles, a back pressure valve is arranged on the outlet pipeline of the first brine discharge pipe and the inlet pipeline of the high-pressure cavity respectively, and the brine discharge speed is slowed down by slowly reducing the pressure through the back pressure valve; The double-well horizontal cavity simulation system comprises two low-pressure cavities connected through a communication pipeline, the communication pipeline is connected with a second brine discharge pipe, and a back pressure valve is arranged on the outlet pipeline of the second brine discharge pipe and the inlet pipeline of the two low-pressure cavities respectively, and the brine discharge speed is slowed down by slowly reducing the pressure through the back pressure valve; The gas phase injection system comprises a gas-liquid separation tank and gas phase injection brine discharge pipelines and gas phase injection brine discharge pipelines connected with the gas-liquid separation tank respectively, the gas phase injection brine discharge pipelines and the gas phase injection brine discharge pipelines are connected in parallel, a gas cylinder, a first gas flow controller and a gas pressure reducing valve connected in parallel are arranged on the gas phase injection brine discharge pipelines, and a second gas flow controller and a vent pipeline connected with the second gas flow controller are arranged on the gas phase injection brine discharge pipelines; The low-pressure cavities are at least partially transparent, and the communication pipeline is a transparent pipeline, a plurality of viewing windows are arranged on the high-pressure cavity along the depth direction; The single-well vertical cavity simulation system and the double-well horizontal cavity simulation system further comprise a high-speed camera for observing the gas-liquid interface depth and the sediment particle migration state in real time.

2. The system of claim 1, wherein, The liquid phase injection system comprises a water storage tank and liquid phase injection brine discharge pipelines and liquid phase injection brine discharge pipelines connected with the water storage tank respectively, the liquid phase injection brine discharge pipelines and the liquid phase injection brine discharge pipelines are connected in parallel, a first liquid flow meter and a turbidity meter are arranged on the liquid phase injection brine discharge pipelines, and a plunger pump connected with the water storage tank, a PLC frequency converter and a second liquid flow meter are arranged on the liquid phase injection brine discharge pipelines.

3. The system of claim 1, wherein the system is configured to simulate the energy storage of the salt caverns with the sedimentation gap. A brine pore pressure sensor is arranged on the low-pressure cavities along the depth direction to monitor the brine pore pressure in the sediment.

4. The system of claim 1, wherein, Pressure gauges are arranged on the inlet pipelines of the high-pressure cavities and low-pressure cavities to monitor the pressure of the injected gas in real time, and pressure gauges are arranged on the outlet pipelines of the first brine discharge pipes and the second brine discharge pipes to monitor the pressure of the discharged brine in real time.

5. The experimental method of claim 1-4, wherein, The system comprises the following steps: S1: preparing a high-impurity salt mine sediment sample; controlling the sediment particle size distribution, and layering and stacking the sediment particles into the high-pressure cavity or the low-pressure cavity; S2 start liquid injection system, fill the high pressure chamber or low pressure chamber with saturated brine, so that the saturated brine can flow out through the gas-liquid separation tank; S3 start high-speed camera and set picture capture parameters; Set the upper limit range of experimental pressure and data recording frequency of monitoring instrument; S4 start gas injection system, inject nitrogen into the high pressure chamber or low pressure chamber in constant flow or constant pressure mode, discharge brine to the liquid tank, and carry out gas injection and brine discharge simulation experiment in the sediment; S5 start liquid injection system, inject brine into the high pressure chamber or low pressure chamber in constant flow or constant pressure mode, discharge gas, and carry out brine injection and gas discharge simulation experiment in the sediment; S6 close the gas inlet switch and the brine inlet switch, open the vent valve and the brine discharge switch, and discharge the sediment in the high pressure chamber and the low pressure chamber to prepare for the next experiment process; Wherein, S4 and S5 can be circulated and reciprocated to simulate the process of gas injection and brine discharge and brine injection and gas discharge respectively.

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