A testing device for testing a sediment space of a salt cavern gas storage

Abstract

The utility model relates to a kind of salt cavern gas storage sediment space test experimental device, including, intercommunication salt well simulation device, including the transparent U-shaped pipe for filling sample, the transparent U-shaped pipe is vertically arranged, two end ports are sealed by detachable closure, every the closure is fixed with intercommunication pipe, the transparent U-shaped pipe is formed by the flange plate butt joint splicing of two structural identical half U-shaped pipes at gas bottom;Circulating dissolution device, including water tank, water pump, the water pump is used to by first pipeline the solution in water tank is pumped into the transparent U-shaped pipe one end after dissolving halite from another end and is pumped out and returns the water tank by second pipeline, to form solution circulation loop.The utility model can realize the simulation of the present situation of underground halite of butt intercommunication well, to test the experiment of gas injection halogen removal rate, sediment void ratio, form slag rate.

Description

Technical Field

[0001] This utility model relates to the field of underground natural gas storage technology, specifically to an experimental device for testing the sediment space of a salt cavern gas storage facility. Background Technology

[0002] Salt rock, due to its extremely low permeability, excellent creep properties, self-healing ability, and strong plastic deformation performance, is regarded by the international energy sector as an ideal medium for underground storage of hydrocarbons such as oil and natural gas. These properties ensure that salt caverns possess excellent airtightness and disturbance resistance during long-term operation. For this reason, salt cavern storage technology has been widely promoted and applied in engineering projects worldwide.

[0003] Most salt rock deposits in my country are layered sedimentary deposits with complex geological compositions, containing numerous insoluble interlayers and impurities. During the underground cavity construction process using the water-soluble method, insoluble substances continuously precipitate and settle, forming a relatively loose sediment layer. This sediment significantly occupies the bottom space of the ore cavity, resulting in a substantial reduction in effective gas storage volume, decreased construction efficiency, and reduced economic viability, severely hindering the large-scale construction and application of salt cavern gas storage facilities in my country. To address the impact of sediment on gas storage space, existing technologies, such as the "Experimental Device for Salt Mine Sediment Porosity and Gas Displacement of Brine" proposed in patent application number 2020112957601, can realize sediment formation and gas displacement experiments in a single-well model under indoor conditions.

[0004] However, this device is difficult to simulate the construction process of connecting two or even multiple wells commonly used in actual salt cavern storage. Therefore, its test results have significant limitations in predicting real gas migration patterns and evaluating the spatial distribution of sediment and the evolution of pore structure, and cannot provide a reliable basis for the design and operation of storage facilities under the interconnected well model. Summary of the Invention

[0005] This invention solves the problem of existing technologies being unable to simulate the soluble mining of underground rock salt in interconnected wells by using transparent U-shaped tubes to simulate the structure of interconnected underground rock salt. By setting the transparent U-shaped tubes as two semi-U-shaped tubes that can be spliced ​​together, the test samples of the reservoir strata can be selected according to the characteristics of salt groups in different mining areas, and can be filled into the device according to the actual stratum sequence. This solves the problem that the current single columnar device cannot simulate the gas release rate, sediment porosity, and slag formation rate of underground rock salt in interconnected wells.

[0006] To achieve the above objectives, the technical solution adopted by this utility model is as follows:

[0007] An experimental apparatus for testing the sediment space of a salt cavern gas storage facility, comprising,

[0008] A connected salt well simulation device includes a transparent U-shaped tube for filling samples. The transparent U-shaped tube is vertically arranged, and the two ends are sealed by detachable caps. A connecting tube is fixed on each cap. The transparent U-shaped tube is formed by splicing two identical half-U-shaped tubes together by connecting them with flanges at their bottoms. A vent valve is provided at the bottom of each half-U-shaped tube.

[0009] The circulating dissolution device includes a water tank and a water pump. The water pump is used to pump the solution in the water tank through one end of the transparent U-shaped tube to dissolve the rock salt. After dissolving the rock salt, the solution returns to the water tank through the other end of the transparent U-shaped tube and a second pipe to form a solution circulation loop.

[0010] The gas injection and brine discharge device includes a compressed air source and a third pipe. One end of the third pipe is connected to the compressed air source, and the other end is connected to the first pipe between the water pump and the transparent U-shaped pipe through a three-way valve.

[0011] Monitoring systems, including,

[0012] A liquid flow meter is installed on the first pipe to monitor the volume of liquid pumped into the first pipe by the water pump. A first valve is installed on the first pipe between the liquid flow meter and the third pipe.

[0013] A gas flow meter is installed on the third pipe to monitor the volume of gas entering the third pipe from the compressed gas source. A second valve is installed on the third pipe located between the gas flow meter and the first pipe.

[0014] A vacuum pressure gauge is installed on the first pipeline, located in the section between the three-way valve and the transparent U-shaped tube, and is used to detect the gas pressure injected by the compressed gas source;

[0015] A concentration detection unit is used to detect the concentration of brine in the water tank.

[0016] Furthermore, an exhaust valve is installed on the cover.

[0017] Furthermore, it also includes,

[0018] The bracket has two opposing vertical support surfaces, each support surface has a horizontally arranged slot, each vertical section of the semi-U-shaped tube is fixed by a clamp, the clamp (502) is connected to a horizontal support rod, the support rod is slidably inserted into the slot, and the clamps of the two semi-U-shaped tubes are connected by a connecting rod.

[0019] Furthermore, the connecting rod is connected to a sling, the lower end of which is fixed to the horizontal section of the semi-U-shaped tube.

[0020] Furthermore, the vertical section of the semi-U-shaped tube is provided with graduations on its outer wall.

[0021] Furthermore, the transparent U-shaped tube is made of acrylic material.

[0022] A method for testing the gas injection and brine discharge rate of sediment in a salt cavern gas storage facility, employing a spatial testing apparatus for sediment in a salt cavern gas storage facility, includes the following steps:

[0023] Step 1: Filling rock salt samples. Based on the characteristics of the ore layer in the mining area and the salt group encountered during core drilling, different salt groups and interlayer rock cores are taken in proportion. The rock salt samples are filled layer by layer from the horizontal section of the semi-U-shaped tube upwards to simulate the filling of the ore layer. After filling is completed, the two horizontal sections of the semi-U-shaped tube are joined and sealed with flanges to form the transparent U-shaped tube.

[0024] Step 2: Inject the solution. The solution can be the water used in actual production in the mining area. Inject the solution into the transparent U-shaped tube until the transparent U-shaped tube is full, and at the same time, inject the solution into the water tank.

[0025] Step 3: Circulation and dissolution. Turn on the water pump to inject the solution in the water tank into the transparent U-shaped tube through the first pipe. The solution can flow back to the water tank through the second pipe. During this period, the concentration detection unit records the brine concentration data in the water tank. Stop the water pump when the fluctuation of the measured value is less than 1% for several consecutive times.

[0026] Step 4: Drain the brine by opening the vent valve to drain the brine from the transparent U-shaped tube.

[0027] Step 5, Aeration and Brine Discharge: Fill the transparent U-shaped tube with saturated brine, turn on the air source and inject air into the transparent U-shaped tube through the first pipe, drain the brine to the top of the sediment, set a preset target position for the water level on this side, continue to inject air until the water level reaches the preset target position, until air leakage occurs, and record the injected air volume V' and sediment accumulation volume V when the water level reaches each set target value. The sediment accumulation volume V can be replaced by marking the mark first, then injecting saturated brine to the mark after removing the sediment, and recording the injected saturated brine volume.

[0028] Step 6: Calculate the brine discharge rate. The brine discharge rate during gas injection is calculated using the formula...

[0029] In the formula, the brine discharge rate of n sediments under the action of gas injection and brine discharge is V', where V is the gas injection volume and V is the sediment accumulation volume.

[0030] Complete the calculation of the gas injection and brine discharge rate.

[0031] A method for testing the porosity of sediment in a salt cavern gas storage facility, employing a spatial testing apparatus for sediment in a salt cavern gas storage facility, includes the following steps:

[0032] Step 1: Filling rock salt samples. Based on the characteristics of the ore layer in the mining area and the salt group encountered during core drilling, different salt groups and interlayer rock cores are taken in proportion. The rock salt samples are filled layer by layer from the horizontal section of the semi-U-shaped tube upwards to simulate the filling of the ore layer. After filling is completed, the two horizontal sections of the semi-U-shaped tube are joined and sealed with flanges to form the transparent U-shaped tube.

[0033] Step 2: Inject the solution. The solution can be the water used in actual production in the mining area. Inject the solution into the transparent U-shaped tube until the transparent U-shaped tube is full, and at the same time, inject the solution into the water tank.

[0034] Step 3: Circulation and dissolution. Turn on the water pump to inject the solution in the water tank into the transparent U-shaped tube through the first pipe. The solution can flow back to the water tank through the second pipe. During this period, the concentration detection unit records the brine concentration data in the water tank. Stop the water pump when the fluctuation of the measured value is less than 1% for several consecutive times.

[0035] Step 4: Drain the brine by opening the vent valve to drain the brine from the transparent U-shaped tube.

[0036] Step 5: Inject saturated brine into the transparent U-shaped tube up to the top surface of the sediment, and record the volume of the injected saturated brine, which is the sediment void volume V. 空 Record the volume V of sediment accumulation inside the transparent U-shaped tube at this time. 总 sludge accumulation volume V 总 One method is to first mark the location, then remove the sediment, and finally inject saturated brine up to the marked point. The recorded volume of injected saturated brine is then used to replace V. 总 ;

[0037] Step 6: Calculate the porosity of the sediment under liquid conditions. The porosity of the sediment is calculated using the formula...

[0038] In the formula, ω is the porosity of the sediment in the liquid state, and V 空 V is the volume of saturated brine injected. 总 This refers to the volume of sediment accumulation.

[0039] Complete the calculation of the porosity of the sediment under liquid conditions.

[0040] A method for testing the sludge formation rate of salt cavern gas storage sediment, employing a spatial testing apparatus for salt cavern gas storage sediment, includes the following steps:

[0041] Step 1: Filling rock salt samples. Based on the characteristics of the ore layers in the mining area and the salt groups encountered during core drilling, different salt groups and interlayer rock cores are collected in proportion. Before loading the samples, the initial weight M of each sample group is measured. 初 The rock salt sample is filled layer by layer upwards through the horizontal section of the semi-U-shaped tube to simulate the filling of the mineral layer. After the filling is completed, the two horizontal sections of the semi-U-shaped tube are joined and sealed by flanges to form the transparent U-shaped tube.

[0042] Step 2: Inject the solution. The solution can be the water used in actual production in the mining area. Inject the solution into the transparent U-shaped tube until the transparent U-shaped tube is full, and at the same time, inject the solution into the water tank.

[0043] Step 3: Circulation and dissolution. Turn on the water pump to inject the solution in the water tank into the transparent U-shaped tube through the first pipe. The solution can flow back to the water tank through the second pipe. During this period, the concentration detection unit records the brine concentration data in the water tank. Stop the water pump when the fluctuation of the measured value is less than 1% for several consecutive times.

[0044] Step 4: Drain the brine by opening the vent valve to drain the brine from the transparent U-shaped tube.

[0045] Step 5: Weigh the sediment. Remove the sediment from the transparent U-shaped tube, dry it, and then weigh the sediment (M). 渣 ;

[0046] Step 6: Calculate the slag formation rate. The slag formation rate is calculated using the formula...

[0047] In the formula, C is the slag formation rate, and M is the slag formation rate. 初 M is the initial weight of the sample. 渣 This represents the weight of the dried sediment after the sample has dissolved.

[0048] Complete the slag formation rate calculation.

[0049] This patent has the following advantages over the prior art.

[0050] This patent utilizes a transparent U-shaped tube to simulate the interconnected underground rock salt structure, solving the difficulty of existing technologies in simulating the soluble mining of underground rock salt in interconnected wells. By setting the transparent U-shaped tube as two semi-U-shaped tubes that can be spliced ​​together, the test samples of the reservoir strata can be selected specifically according to the characteristics of salt groups (ore layers) in different mining areas. The samples can be filled into the device from bottom to top according to the actual stratum sequence, which can simulate the situation of tight bottom and loose top in the ore layer. This solves the difficulty of the current single column device in simulating the actual working conditions of salt cavern formation and sediment accumulation. At the same time, this device can measure the amount of brine that can be discharged from the sediment at different depths and the maximum amount of brine that can be discharged from the sediment in sections. Attached Figure Description

[0051] Figure 1 This is a schematic diagram of the structure of this device.

[0052] Figure 2 This is a schematic diagram of the structure of a simulated salt well.

[0053] Figure 3 This is a set of dissolution curves.

[0054] Figure 4 The graphs show the three sets of gas injection and brine discharge rate curves. Detailed Implementation

[0055] To make the technical means, creative features, objectives and effects of this utility model easier to understand, the present utility model will be further described below in conjunction with specific embodiments.

[0056] Figures 1-3 As shown, a docking and interconnecting underground rock salt experimental device includes,

[0057] The connected salt well simulation device 10 includes a transparent U-shaped tube 101 for filling samples. The transparent U-shaped tube 101 is vertically arranged, and its two ends are sealed by detachable caps 102. Each cap 102 is fixed with a connecting pipe 1021, and a valve is installed on the connecting pipe 1021 to control its opening and closing. The transparent U-shaped tube 101 is formed by splicing two identical half-U-shaped tubes 1011 together by connecting them with flanges at their bottoms. Each half-U-shaped tube 1011 is provided with a vent valve 1012 at its bottom.

[0058] To ensure the transparent U-shaped tube 101 is vertically positioned, it needs to be mounted on a bracket 50. The bracket 50, welded from channel steel, has two opposing vertical support surfaces. Each support surface has a horizontally oriented slot 501, formed by welding a cylindrical tube onto the vertical support surface. For ease of fabrication and fixation, the two cylinders are symmetrically arranged. Furthermore, for convenient fixation, each vertical segment of the semi-U-shaped tube 1011 is secured by a clamp 502. A horizontal support rod 5021 is welded to the outer side of the clamp 502, and the support rod 5021 is slidably inserted into the slot 501. The horizontal support rod 5021 can be pulled out of the slot 501 by disassembling the clamp 502. In order to ensure that the transparent U-shaped tube 101 can be fixed stably, the cylinder can be radially threaded to fix the top bolt. At the same time, in order to ensure the stability of the transparent U-shaped tube 101 after filling the sample and filling with water, the clamps 502 of the two half-U-shaped tubes 1011 are connected by a connecting rod 5022. The connecting rod 5022 is connected to two slings 5023. The lower ends of the two slings 5023 are respectively fixed to the horizontal pipe sections of the two half-U-shaped tubes 1011 to form a stable support, improve the load-bearing capacity of the transparent U-shaped tube 101, and avoid breakage.

[0059] The circulating dissolving device 20 includes a water tank 201 and a water pump 202. The water pump 202 is used to pump the solution in the water tank 201 through one end of the transparent U-shaped tube 101 to dissolve the rock salt through the first pipe 203. After dissolving the rock salt, the solution returns to the water tank 201 through the other end of the transparent U-shaped tube 101 through the second pipe 204 to form a solution circulation loop. The water pump 202 can be a submersible pump or other water pumps. A valve is installed at the outlet of the water pump 202 and then connected to the first pipe 203. The volume requirement of the water tank 201 is sufficient to remain unsaturated after dissolving the soluble salts in the rock salt.

[0060] The gas injection and brine discharge device 30 includes a compressed air source 301 and a third pipe 302. One end of the third pipe 302 is connected to the compressed air source 301, and the other end is connected to the first pipe 203 between the water pump 202 and the transparent U-shaped pipe 101 through a three-way valve.

[0061] Monitoring systems, including

[0062] A liquid flow meter 401 is installed on the first pipe 203 to monitor the volume of liquid pumped into the first pipe 203 by the water pump 202. A first valve 2031 is installed on the first pipe 203 located between the liquid flow meter 401 and the third pipe 302.

[0063] A gas flow meter 402 is installed on the third pipe 302 to monitor the volume of gas entering the third pipe 302 from the compressed gas source 301. A second valve 3021 is installed on the third pipe 302 located between the gas flow meter 402 and the first pipe 203.

[0064] A vacuum pressure gauge 403 is installed on the first pipe 203, located in the section between the three-way valve and the transparent U-shaped tube 101, and is used to detect the gas pressure injected by the compressed gas source 301;

[0065] The concentration detection unit 404 can be a Baume meter to detect the concentration of brine in the water tank 201.

[0066] Furthermore, in order to facilitate the filling of the transparent U-shaped tube 101 with saturated brine, an exhaust valve 1022 is installed on the cap 102.

[0067] Furthermore, to facilitate observation and data recording, the outer wall of the vertical section of the semi-U-shaped tube 1011 is provided with graduations, and the transparent U-shaped tube 101 is made of acrylic material.

[0068] An experimental method for the gas injection and brine removal rate of sediment in a salt cavern gas storage facility, using a connected-well underground rock salt experimental device, includes the following steps:

[0069] Step 1: Filling rock salt samples. Based on the characteristics of the ore layer in the mining area and the salt group encountered during core drilling, different salt groups and interlayer rock cores are taken in proportion. The rock salt samples are filled layer by layer upward through the horizontal pipe section of the semi-U-shaped tube 1011 to simulate the filling of the ore layer. After the filling is completed, the two horizontal pipe sections of the semi-U-shaped tube 1011 are joined and sealed by flanges to form the transparent U-shaped tube 101.

[0070] Step 2: Inject the solution. The solution can be the water used in actual production in the mining area. Inject the solution into the transparent U-shaped tube 101 until the transparent U-shaped tube 101 is full. At the same time, inject the solution into the water tank 201.

[0071] Step 3: Circulation and dissolution. The water pump 202 is turned on to inject the solution in the water tank 201 into the transparent U-shaped tube 101 through the first pipe 203. The solution can flow back to the water tank 201 through the second pipe 204. During this process, the concentration detection unit 404 records the brine concentration data in the water tank 201. The water pump 202 is stopped when the fluctuation of the measured value is less than 1% for several consecutive measurements. The concentration is measured every hour, and the concentration detection unit 404 must show a fluctuation of less than 1% for at least eight consecutive measurements.

[0072] Step 4: Drain the brine by opening the vent valve 1012 to drain the brine from the transparent U-shaped tube 101.

[0073] Step 5, Aeration and Brine Discharge: Fill the transparent U-shaped tube 101 with saturated brine, turn on the gas source 301 and inject gas into the transparent U-shaped tube 101 through the first pipe 203, drain the water to the top of the sediment, set a preset target position for the water level on this side, continue to inject gas until the water level reaches the preset target position, until gas leakage occurs, and record the injected gas volume V' and sediment accumulation volume V when the water level reaches each set target value. The sediment accumulation volume V can be replaced by marking first, then injecting saturated brine to the marked position after removing the sediment, and recording the injected saturated brine volume. Gas leakage refers to the phenomenon that when the gas-brine interface in the connected well storage exceeds the limit position, the injected gas leaks out of the brine discharge well from the gas-brine interface along the connected channel.

[0074] Step 6: Calculate the brine discharge rate. The brine discharge rate during gas injection is calculated using the formula...

[0075] In the formula, the brine discharge rate of n sediments under the action of gas injection and brine discharge is V', where V is the gas injection volume and V is the sediment accumulation volume.

[0076] Complete the calculation of the gas injection and brine discharge rate.

[0077] A method for testing the porosity of sediment in a salt cavern gas storage facility, using a connected-well underground rock salt testing apparatus, includes the following steps:

[0078] Step 1: Filling rock salt samples. Based on the characteristics of the ore layer in the mining area and the salt group encountered during core drilling, different salt groups and interlayer rock cores are taken in proportion. The rock salt samples are filled layer by layer upward through the horizontal pipe section of the semi-U-shaped tube 1011 to simulate the filling of the ore layer. After the filling is completed, the two horizontal pipe sections of the semi-U-shaped tube 1011 are joined and sealed by flanges to form the transparent U-shaped tube 101.

[0079] Step 2: Inject the solution. The solution can be the water used in actual production in the mining area. Inject the solution into the transparent U-shaped tube 101 until the transparent U-shaped tube 101 is full. At the same time, inject the solution into the water tank 201.

[0080] Step 3: Circulation and dissolution. The water pump 202 is turned on to inject the solution in the water tank 201 into the transparent U-shaped tube 101 through the first pipe 203. The solution can flow back to the water tank 201 through the second pipe 204. During this process, the concentration detection unit 404 records the brine concentration data in the water tank 201. The water pump 202 is stopped when the fluctuation of the measured value is less than 1% for several consecutive measurements. The concentration is measured every hour, and the concentration detection unit 404 must show a fluctuation of less than 1% for at least eight consecutive measurements.

[0081] Step 4: Drain the brine by opening the vent valve 1012 to drain the brine from the transparent U-shaped tube 101.

[0082] Step 5: Inject saturated brine into the transparent U-shaped tube 101 up to the top surface of the sediment, and record the volume of the injected saturated brine, which is the sediment void volume V. 空 Record the sediment accumulation volume V inside the transparent U-shaped tube 101 at this time. 总 sludge accumulation volume V 总 One method is to first mark the location, then remove the sediment, and finally inject saturated brine up to the marked point. The recorded volume of injected saturated brine is then used to replace V. 总 ;

[0083] Step 6: Calculate the porosity of the sediment under liquid conditions. The porosity of the sediment is calculated using the formula...

[0084] In the formula, ω is the porosity of the sediment in the liquid state, and V 空 V is the volume of saturated brine injected. 总 This refers to the volume of sediment accumulation.

[0085] Complete the calculation of the porosity of the sediment under liquid conditions.

[0086] A method for testing the slag formation rate of sediment in a salt cavern gas storage facility, using a connected-well underground rock salt experimental apparatus, includes the following steps:

[0087] Step 1: Filling rock salt samples. Based on the characteristics of the ore layers in the mining area and the salt groups encountered during core drilling, different salt groups and interlayer rock cores are collected in proportion. Before loading the samples, the initial weight M of each sample group is measured. 初 The rock salt sample is filled layer by layer upwards through the horizontal section of the semi-U-shaped tube 1011 to simulate the filling of the mineral layer. After the filling is completed, the two horizontal sections of the semi-U-shaped tube 1011 are joined and sealed by flanges to form the transparent U-shaped tube 101.

[0088] Step 2: Inject the solution. The solution can be the water used in actual production in the mining area. Inject the solution into the transparent U-shaped tube 101 until the transparent U-shaped tube 101 is full. At the same time, inject the solution into the water tank 201.

[0089] Step 3: Circulation and dissolution. The water pump 202 is turned on to inject the solution in the water tank 201 into the transparent U-shaped tube 101 through the first pipe 203. The solution can flow back to the water tank 201 through the second pipe 204. During this process, the concentration detection unit 404 records the brine concentration data in the water tank 201. The water pump 202 is stopped when the fluctuation of the measured value is less than 1% for several consecutive measurements. The concentration is measured every hour, and the concentration detection unit 404 must show a fluctuation of less than 1% for at least eight consecutive measurements.

[0090] Step 4: Drain the brine by opening the vent valve 1012 to drain the brine from the transparent U-shaped tube 101.

[0091] Step 5: Weigh the sediment. Remove the sediment from the transparent U-shaped tube 101, dry it, and then weigh the sediment. ;

[0092] Step 6: Calculate the slag formation rate. The slag formation rate is calculated using the formula...

[0093] In the formula, C is the slag formation rate, and M is the slag formation rate. 初 M is the initial weight of the sample. 渣 This represents the weight of the dried sediment after the sample has dissolved.

[0094] Complete the slag formation rate calculation.

[0095] In practical applications, if it is necessary to simultaneously test the aeration and brine discharge rate, sediment porosity, and slag formation rate, a single sample can be tested at the same time. The specific steps are as follows.

[0096] The following are the specific experimental setup and testing methods.

[0097] The transparent U-shaped tube 101 is made of acrylic material with an inner diameter of 130mm, an outer diameter of 170mm, a wall thickness of 20mm, a compressive strength of ≥0.5MPa, a vertical height of 2m, and a horizontal section of 0.75m. The vertical tube section is marked with graduations. The transparent U-shaped tube 101 is made by dividing it into two half-U-shaped tubes of the same size, which facilitates the filling of rock salt samples from the bottom and the cleaning of sediment.

[0098] Compressed air source 301 uses an oil-free air compressor with a nominal volumetric flow rate of 100L / min and a rated discharge pressure of 0.7Mpa;

[0099] The water pump 202 is of type QDX3-17-0.37S, with a diameter of 25mm and a flow rate of 3m³ / h.

[0100] Head 17m;

[0101] Water tank 201, made of HDPE polyethylene; dimensions: 180*108*110cm; capacity: 1500L.

[0102] The flow meter for measuring gas volume and the flow meter 401 for liquid can be electromagnetic flow meters, the concentration detection unit 404 uses a Baume degree measuring instrument, and the installation valves, vent valves, etc. are all conventional technical means and will not be described.

[0103] Taking a certain mining area as an example in the experiment, the average content of NaCl in the injection water used for production in this mining area was 30.45 g / l, the average content of CaCl2 was 6.3 g / l, the average content of CaSO4 was 0.64 g / l, and the average pH value was 9.45.

[0104] Step 1: Filling rock salt samples. Based on the salt strata encountered during core drilling, core samples from different salt strata and interlayers were collected in proportion, totaling 2625 cm in length. The total length of each core sample group was 375 cm. Sampling was conducted at a ratio of 1:200 to the average thickness of the strata in the mining area. Before loading the samples, the initial weight M of each sample group was measured. 初， The rock salt sample is filled layer by layer upwards through the horizontal section of the semi-U-shaped tube 1011 to simulate the filling of the mineral layer. After the filling is completed, the two horizontal sections of the semi-U-shaped tube 1011 are joined and sealed by flanges to form the transparent U-shaped tube 101. The specific sampling and stratification are as follows.

[0105]

[0106] Step 2: Inject the solution. The solution can be the water used in actual production in the mining area. Inject the solution into the transparent U-shaped tube 101 until the transparent U-shaped tube 101 is full. At the same time, inject the solution into the water tank 201.

[0107] Step 3: Circulation and Dissolution. The water pump 202 is turned on to inject the solution in the water tank 201 into the transparent U-shaped tube 101 through the first pipe 203. The solution can flow back to the water tank 201 through the second pipe 204. During this process, the concentration detection unit 404 records the brine concentration data in the water tank 201. The water pump 202 is stopped when the fluctuation of multiple consecutive measurements is less than 1%. Figure 3 As shown, the concentration is detected every hour, and the fluctuation of the measured value of the concentration detection unit 404 is less than 1% for at least 8 consecutive times.

[0108] Step 4: Drain the brine by opening the vent valve 1012 to drain the brine from the transparent U-shaped tube 101.

[0109] Step 5, Aeration and Brine Discharge Rate Experiment: Fill the transparent U-shaped tube 101 with saturated brine, which is made by dissolving sodium chloride in pure water until saturated. Turn on the gas source 301 and inject gas into the transparent U-shaped tube 101 through the first pipe 203. Drain the brine to the top of the sediment and set a preset target position for the water level on this side. In this embodiment, the water level is recorded at intervals of 30cm drop. Continue to inject gas until the water level reaches the preset target position until gas leakage occurs. Record the volume of gas injected V' and the volume of sediment accumulation V when the water level reaches each set target value. The volume of sediment accumulation V can be replaced by marking the target position first, removing the sediment, injecting saturated brine to the marked position, and recording the volume of saturated brine injected.

[0110] After completing the aeration and brine discharge rate experiment, saturated brine is reintroduced into the transparent U-shaped tube 101 until it reaches the top surface of the sediment. The volume of saturated brine injected is recorded as the sediment void volume V. 空 Record the sediment accumulation volume V inside the transparent U-shaped tube 101 at this time. 总 sludge accumulation volume V 总 One method is to first mark the location, then remove the sediment, and finally inject saturated brine up to the marked point. The recorded volume of injected saturated brine is then used to replace V. 总 ;

[0111] After completing the test on the porosity of the sediment in liquid state, the sediment was removed from the transparent U-shaped tube 101, dried, and then weighed. ;

[0112] Step 6: Prepare three sets of samples. The data for the gas injection and brine removal rates are as follows.

[0113]

[0114] Three sets of samples were prepared, and the porosity data of the sediment are as follows:

[0115]

[0116] Three sets of samples were prepared, and the slag formation rate was calculated as follows:

[0117]

[0118]

[0119] It was found that under the action of aeration and brine discharge, the brine discharge capacity of the sediment generally showed a gradual decreasing trend with the increase of the brine discharge depth, and the porosity of the sediment gradually decreased. This is consistent with the characteristic that the porosity of the lower sediment is smaller than that of the upper sediment under the actual sediment layer-by-layer accumulation, which characterizes the layer-by-layer compaction effect of the sediment body.

[0120] Based on the results of this experiment, targeted tests can be conducted on underground salt cavern gas storage projects in different mining areas to guide the gas injection and brine discharge work of gas storage wells, make reasonable use of the sediment gaps at the bottom of the salt cavern cavity to increase the gas storage capacity, and quantitatively estimate the reasonable brine discharge volume for different gas storage wells to improve the safety of brine discharge during capacity expansion.

[0121] This document uses specific examples to illustrate the principles and embodiments of this utility model. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this utility model. At the same time, for those skilled in the art, there will be changes in specific embodiments and application scope based on the ideas of this utility model. Therefore, the content of this specification should not be construed as a limitation of this utility model.

Claims

1. An experimental apparatus for testing the sediment space of a salt cavern gas storage tank, characterized in that, include, The interconnected salt well simulation device (10) includes a transparent U-shaped tube (101) for filling samples. The transparent U-shaped tube (101) is vertically arranged, and the two ends are sealed by a detachable cap (102). A connecting pipe (1021) is fixed on each cap (102). The transparent U-shaped tube (101) is formed by splicing two identical half-U-shaped tubes (1011) together by connecting them with flanges at their bottoms. A vent valve (1012) is provided at the bottom of each half-U-shaped tube (1011). The circulating dissolving device (20) includes a water tank (201) and a water pump (202). The water pump (202) is used to pump the solution in the water tank (201) through the first pipe (203) into the water tank (201) through one end of the transparent U-shaped tube (101) to dissolve the rock salt. The solution is then returned to the water tank (201) through the other end of the transparent U-shaped tube (101) through the second pipe (204) to form a solution circulation loop. The gas injection and brine discharge device (30) includes a compressed air source (301) and a third pipe (302). One end of the third pipe (302) is connected to the compressed air source (301), and the other end is connected to the first pipe (203) between the water pump (202) and the transparent U-shaped pipe (101) through a three-way valve. Monitoring systems, including A liquid flow meter (401) is installed on the first pipe (203) to monitor the volume of liquid pumped into the first pipe (203) by the water pump (202). A first valve (2031) is installed on the first pipe (203) located between the liquid flow meter (401) and the third pipe (302). A gas flow meter (402) is installed on the third pipe (302) to monitor the volume of gas entering the third pipe (302) from the compressed gas source (301). A second valve (3021) is installed on the third pipe (302) located between the gas flow meter (402) and the first pipe (203). A vacuum pressure gauge (403) is installed on the first pipe (203) in the section between the three-way valve and the transparent U-tube (101) to detect the gas pressure injected by the compressed gas source (301); The concentration detection unit (404) is used to detect the concentration of brine in the water tank (201).

2. The experimental apparatus for testing the sediment space of a salt cavern gas storage tank according to claim 1, characterized in that, An exhaust valve (1022) is installed on the cover (102).

3. The experimental apparatus for testing the sediment space of a salt cavern gas storage tank according to claim 2, characterized in that, It also includes, The bracket (50) has two opposing vertical support surfaces, each support surface having a horizontally arranged slot (501). The vertical pipe section of each of the semi-U-shaped tubes (1011) is fixed by a clamp (502). A horizontal support rod (5021) is connected to the clamp (502). The support rod (5021) is slidably inserted into the slot (501). The clamps (502) of the two semi-U-shaped tubes (1011) are connected by a connecting rod (5022).

4. The experimental apparatus for testing the sediment space of a salt cavern gas storage tank according to claim 3, characterized in that, The connecting rod (5022) is connected to a sling (5023), and the lower end of the sling (5023) is fixed to the horizontal section of the semi-U-shaped tube (1011).

5. The experimental apparatus for testing the sediment space of a salt cavern gas storage tank according to claim 4, characterized in that, The vertical section of the semi-U-shaped tube (1011) has graduations on its outer wall.

6. The experimental apparatus for testing the sediment space of a salt cavern gas storage tank according to claim 1, characterized in that, The transparent U-shaped tube (101) is made of acrylic material.

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