An experimental device for storing, injecting, and discharging brine from salt cavern sediment.

Abstract

This invention provides an experimental device for storing, injecting, and discharging brine from salt cavern sediment, comprising: a gas cylinder, a reference chamber for measuring the porosity of sediment, a brine tank, a first sediment container for loading sediment, a second sediment container for loading sediment, a vacuum mechanism for vacuum treatment of the first and second sediment containers, a first compaction piston, a second compaction piston, and a third compaction piston. The gas cylinder is connected to the first sediment container via a first pipeline. The reference chamber, one end of the brine tank, the vacuum mechanism, and the second sediment container are all connected to the first pipeline. The other end of the brine tank is connected to both the first and second sediment containers via second pipelines. The first and second compaction pistons are slidably installed in the second sediment container, and the third compaction piston is slidably installed in the first sediment container.

Description

Technical Field

[0001] This invention relates to the field of gas injection and brine discharge technology for salt cavern gas storage, and particularly to an experimental device for gas injection and brine discharge of salt cavern sediment. Background Technology

[0002] Salt cavern gas storage facilities are typically constructed using a single-well oil-pad water-soluble cavity-building technique. The main process involves drilling to connect a deep salt layer, buried at depths of several hundred to over two thousand meters, to the surface. After cementing, a cavity-building outer and inner tubing string is installed in the wellbore. Fresh water or unsaturated brine is injected downhole to dissolve the salt layer, with an oil pad layer controlling the upward dissolution. As the salt rock dissolves, the cavity expands, and the depths of the oil pad, inner tubing, and outer tubing are adjusted as needed to control the cavity's dissolution boundary, ultimately obtaining a cavity that meets the storage requirements. High-pressure natural gas is then injected into the cavity while brine is simultaneously discharged (i.e., "gas injection and brine discharge"), forming a large underground gas storage cavern. After water-soluble cavity building is completed, water-insoluble "impurities" accumulate at the bottom of the salt cavity, forming a "sediment" deposit, with the voids within the sediment being occupied by brine. In the traditional gas storage construction technology, the brine discharge process involves placing the brine discharge pipe column above the "sludge accumulation surface". Ultimately, most of the brine above the discharge pipe opening is squeezed to the ground by natural gas, and then the discharge pipe is removed to complete the construction of the gas storage facility.

[0003] Traditional gas storage technology utilizes the pure brine space outside the sediment accumulation within the cavities to store gas. For low-impurity salt mines, only a small amount of sediment remains after water-soluble cavity construction, and large gas storage tanks can be formed after gas injection and brine removal. However, for high-impurity salt mines, a large amount of sediment remains after water-soluble cavity construction, and only small-scale gas storage tanks can be formed after gas injection and brine removal, resulting in a very low input-output ratio and poor feasibility of gas storage. In reality, there is still a considerable amount of space filled with brine within the sediment that can be utilized. Therefore, to improve the cavity utilization rate, displace the brine within the sediment, and ensure the economic benefits of gas storage, it is necessary to conduct physical simulation experiments on the porosity of insoluble sediment accumulation in salt cavern gas storage tanks, gas drive efficiency, and different gas injection and brine removal methods (two injections and one removal, one injection and one removal, and bottom brine removal in horizontal wells). There are currently no relevant experimental devices in the technology. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide an experimental device for storing, injecting and discharging brine from salt cavern sediment, which addresses the shortcomings of the prior art.

[0005] The technical solution of the present invention to solve the above-mentioned technical problems is as follows: A salt cavern sediment gas storage, gas injection, and brine discharge experimental device, comprising: a gas cylinder, a reference chamber for measuring the porosity of sediment, a brine tank, a first sediment container for loading sediment, a second sediment container for loading sediment, a vacuum mechanism for vacuum treatment of the first and second sediment containers, a first compaction piston, a second compaction piston, and a third compaction piston. The gas cylinder is connected to the first sediment container through a first pipeline. The reference chamber, one end of the brine tank, the vacuum mechanism, and the second sediment container are all connected to the first pipeline. The other end of the brine tank is connected to the first sediment container and the second sediment container respectively through a second pipeline. The first compaction piston and the second compaction piston are slidably installed in the second sediment container, and the third compaction piston is slidably installed in the first sediment container.

[0006] The beneficial effects of adopting the technical solution of this invention are as follows: The sediment container is used to simulate the cavity, loading the sediment, brine, and gas used in the experiment. The reference chamber is used to measure the porosity of the sediment inside the sediment container based on the principle of isothermal gas expansion. The vacuum mechanism is used to evacuate the inside of the sediment container. The setting of the compaction piston enables the sediment container to compact the insoluble sediment. Experiments on the porosity of insoluble sediment accumulation in salt cavern gas storage, gas drive efficiency, and physical simulation experiments on different gas injection and brine discharge methods (two injections and one discharge, one injection and one discharge, and bottom discharge of brine in horizontal wells) are completed.

[0007] Furthermore, a gas pressure gauge and a gas flow meter are provided on the first pipeline between the gas cylinder and the reference chamber. The gas pressure gauge is adjacent to the gas cylinder, and the gas flow meter is adjacent to the reference chamber. A weighing component for measuring the weight of the brine tank is installed at the bottom of the brine tank. A first pressure sensor is connected to one side of the top of the second sediment container, and a second pressure sensor is connected to the other side of the top of the second sediment container. A third pressure sensor is connected to the top of the first sediment container. A fourth pressure sensor (38) is connected to the top of the reference chamber. A fifth pressure sensor is installed on the first pipeline between the reference chamber and the vacuum mechanism.

[0008] The beneficial effects of adopting the above-mentioned further technical solution are as follows: A gas flow meter is used to measure the experimental gas injection rate. A pressure sensor is used to measure the internal pressure of the sediment container and each pipeline. A weighing component is used to measure the mass of discharged brine and calculate the discharge flow rate. A gas pressure gauge is used to monitor pressure changes. The depressurized gas is connected to the first sediment container, the second sediment container, and the reference chamber through pipelines. This facilitates the user in obtaining pressure, flow rate, and other parameter data at different locations.

[0009] Furthermore, a first displacement sensor for measuring the displacement of the second compaction piston and a second displacement sensor for measuring the displacement of the first compaction piston are installed on the top of the second sediment container. The second compaction piston is located on one side of the top of the second sediment container, and the first compaction piston is located on the other side of the top of the second sediment container. The first displacement sensor is correspondingly arranged with the second compaction piston, and the second displacement sensor is correspondingly arranged with the first compaction piston. A third displacement sensor for measuring the displacement of the third compaction piston is installed on the top of the first sediment container, and the third displacement sensor is correspondingly arranged with the third compaction piston.

[0010] The beneficial effects of adopting the above-mentioned further technical solution are: the displacement sensor is used to measure the compaction stroke of the compaction piston in the sediment container, which makes it easier for users to obtain the stroke parameter data of the compaction piston, provide data support for the experiment, and improve the reliability of the experimental device.

[0011] Furthermore, it also includes: a data acquisition device, wherein the gas flow meter, the weighing component, the first pressure sensor, the second pressure sensor, the third pressure sensor, the fourth pressure sensor, the fifth pressure sensor, the first displacement sensor, the second displacement sensor, and the third displacement sensor are all connected to the data acquisition device.

[0012] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the data acquisition instrument is used to collect various data such as pressure, flow rate, and mass. The gas flow meter is placed after the gas pressure reducing valve, and the displacement sensor and pressure sensor are connected to the first sediment container and the second sediment container, respectively, with the other end connected to the data acquisition instrument. The data acquisition instrument is connected to a computer, and the computer is equipped with dedicated acquisition software for collecting and processing various data.

[0013] Furthermore, the vacuum mechanism includes: a vacuum pressure gauge, a vacuum pump, a drying tank, and a buffer tank. The vacuum pump is connected to the drying tank, the drying tank is connected to the buffer tank, and the buffer tank is connected to the first pipeline.

[0014] The beneficial effects of adopting the above-mentioned further technical solution are: the vacuum pump is connected to the sediment container to eliminate the influence of foreign gases, improve the accuracy of experimental data, and improve the stability and reliability of the experimental device.

[0015] Furthermore, the first sediment container is a cylindrical sediment container, and the second sediment container is a U-shaped sediment container.

[0016] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the cylindrical and U-shaped sediment containers are used to simulate the cavity and load the sediment, brine, and gas used in the experiment. The setting of the compaction piston enables the sediment container to compact insoluble sediment.

[0017] Furthermore, the first pipeline is equipped with a gas pressure reducing valve, a first valve, a second valve, a fifth valve, a sixth valve, a seventeenth valve, an eighteenth valve, and a nineteenth valve. The gas pressure reducing valve is adjacent to the gas cylinder. The gas pressure reducing valve, the second valve, the seventeenth valve, the eighteenth valve, and the fifth valve are sequentially installed on the first pipeline. The fifth valve is adjacent to the first sediment container and is connected to the first end of the first sediment container. The first valve is connected to the first pipeline between the gas pressure reducing valve and the second valve. The sixth valve is connected to the first pipeline between the fifth valve and the first sediment container. One end of the nineteenth valve is connected to the first pipeline between the second valve and the seventeenth valve, and the other end of the nineteenth valve is connected to the first pipeline between the eighteenth valve and the fifth valve.

[0018] The beneficial effects of adopting the above-mentioned further technical solution are: the gas pressure reducing valve can adjust the injected high-pressure gas to the pressure required for the experiment, ensuring experimental safety. The gas cylinder's pressure is adjusted to the required level through the gas pressure reducing valve. The depressurized gas is connected to the first sediment container, the second sediment container, and the reference chamber through pipelines. Valves are used to control the switching of each pipeline, allowing users to flexibly adjust the on / off state of different pipeline positions according to actual experimental needs and experimental objectives, thus improving the applicability of the experimental apparatus.

[0019] Furthermore, a third pipeline is connected to the first pipeline between the second valve and the gas pressure reducing valve. The third pipeline is connected to the first end of the second sediment container via a seventh valve, the second end of the second sediment container via a tenth valve, and the second end of the first sediment container via a thirteenth valve. The third end of the second sediment container is connected to the first pipeline between the eighteenth valve and the fifth valve via an eighth valve, and the fourth end of the second sediment container is connected to the first pipeline between the eighteenth valve and the fifth valve via an eleventh valve.

[0020] The beneficial effects of adopting the above-mentioned further technical solution are: the valve is used to control the switching of each pipeline, which makes it convenient for users to flexibly adjust the on / off state of different positions of the pipeline according to the actual experimental needs and experimental objectives, thereby improving the applicability of the experimental device.

[0021] Furthermore, the reference chamber is connected to the other end of the nineteenth valve and the fifth valve via a first pipeline, and the vacuum mechanism is connected to the other end of the nineteenth valve and the fifth valve via a fourth valve.

[0022] The beneficial effects of adopting the above-mentioned further technical solution are: the valve is used to control the switching of each pipeline, which makes it convenient for users to flexibly adjust the on / off state of different positions of the pipeline according to the actual experimental needs and experimental objectives, thereby improving the applicability of the experimental device.

[0023] Furthermore, the bottom of the second sediment container is connected to the second pipeline via the fifteenth valve, the bottom of the first sediment container is connected to the second pipeline via the sixteenth valve, the middle part of the second sediment container is connected to the second pipeline via the ninth valve, the fourth end of the second sediment container is connected to the second pipeline via the twelfth valve, and one end of the brine tank is connected to the first pipeline via the fourteenth valve.

[0024] The beneficial effects of adopting the above-mentioned further technical solution are: the valve is used to control the switching of each pipeline, which makes it convenient for users to flexibly adjust the on / off state of different positions of the pipeline according to the actual experimental needs and experimental objectives, thereby improving the applicability of the experimental device.

[0025] The advantages of additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the structure of the salt cavern sediment gas storage, gas injection, and brine discharge experimental device provided in an embodiment of the present invention.

[0027] Reference numerals: 1. First valve; 2. Second valve; 3. Third valve; 4. Fourth valve; 5. Fifth valve; 6. Sixth valve; 7. Seventh valve; 8. Eighth valve; 9. Ninth valve; 10. Tenth valve; 11. Eleventh valve; 12. Twelfth valve; 13. Thirteenth valve; 14. Fourteenth valve; 15. Fifteenth valve; 16. Sixteenth valve; 17. Seventeenth valve; 18. Eighteenth valve; 19. Nineteenth valve; 20. Gas pressure reducing valve; 21. Gas cylinder; 22. Gas pressure gauge; 23. Gas flow meter; 24. Reference chamber; 25. Vacuum pressure gauge; 26. 27. Vacuum pump; 28. Drying tank; 29. ​​Buffer tank; 30. Brine tank; 31. Weighing component; 32. First sediment container; 33. Second sediment container; 34. First compaction piston; 35. Second compaction piston; 36. First pressure sensor; 37. Second pressure sensor; 38. Third pressure sensor; 39. Fourth pressure sensor; 40. Fifth pressure sensor; 41. First displacement sensor; 42. Second displacement sensor; 43. Third displacement sensor; 44. Data acquisition instrument; 45. Third compaction piston; 46. Vacuum mechanism; 47. First pipeline; 48. Second pipeline; 49. Third pipeline. Detailed Implementation

[0028] The principles and features of the present invention are described below with reference to the accompanying drawings. The examples given are only for explaining the present invention and are not intended to limit the scope of the present invention.

[0029] like Figure 1 As shown, this embodiment of the invention provides an experimental device for storing, injecting, and discharging brine from salt cavern sediment, comprising: a gas cylinder 21, a reference chamber 24 for measuring the porosity of sediment, a brine tank 29, a first sediment container 31 for loading sediment, a second sediment container 32 for loading sediment, a vacuum mechanism 45 for vacuum treatment of the first sediment container 31 and the second sediment container 32, a first compaction piston 33, a second compaction piston 34, and a third compaction piston 44. The gas cylinder 21 is connected to the first sediment container 31 via a first pipeline 46. The reference chamber 24, one end of the brine tank 29, the vacuum mechanism 45, and the second sediment container 32 are all connected to the first pipeline 46. The other end of the brine tank 29 is connected to the first sediment container 31 and the second sediment container 32 via a second pipeline 47. The first compaction piston 33 and the second compaction piston 34 are slidably installed in the second sediment container 32, and the third compaction piston 44 is slidably installed in the first sediment container 31.

[0030] The beneficial effects of adopting the technical solution of this invention are as follows: The sediment container is used to simulate the cavity, loading the sediment, brine, and gas used in the experiment. The reference chamber is used to measure the porosity of the sediment inside the sediment container based on the principle of isothermal gas expansion. The vacuum mechanism is used to evacuate the inside of the sediment container. The setting of the compaction piston enables the sediment container to compact the insoluble sediment. Experiments on the porosity of insoluble sediment accumulation in salt cavern gas storage, gas drive efficiency, and physical simulation experiments on different gas injection and brine discharge methods (two injections and one discharge, one injection and one discharge, and bottom discharge of brine in horizontal wells) are completed.

[0031] The gas cylinder is a high-pressure gas cylinder. Reference chamber: Volume: 5000mL, Quantity: 1 unit, Material: 316 stainless steel, Working pressure: 5MPa. The dashed lines in the diagram represent signal and electrical connections.

[0032] The sediment container is made of transparent acrylic or other materials, which enables visualization of gas injection and brine discharge; the sediment container can achieve the compaction of insoluble sediment with a compaction pressure of 2MPa; after the sediment is compacted, the sediment porosity can be measured, gas injection and brine discharge operations can be performed, and parameters such as gas injection rate, brine discharge rate, and pressure can be measured; it can simulate three modes: single-chamber sediment injection and discharge, U-shaped cavity two-injection and discharge, and bottom discharge of brine in horizontal wells.

[0033] like Figure 1As shown, further, a gas pressure gauge 22 and a gas flow meter 23 are provided on the first pipeline between the gas cylinder 21 and the reference chamber 24. The gas pressure gauge 22 is adjacent to the gas cylinder 21, and the gas flow meter 23 is adjacent to the reference chamber 24. A weighing component 30 for measuring the weight of the brine tank 29 is installed at the bottom of the brine tank 29. A first pressure sensor 35 is connected to one side of the top of the second sediment container 32, and a second pressure sensor 36 is connected to the other side of the top of the second sediment container 32. A third pressure sensor 37 is connected to the top of the first sediment container 31. A fourth pressure sensor 38 is connected to the top of the reference chamber 24. A fifth pressure sensor 39 is installed on the first pipeline between the reference chamber 24 and the vacuum mechanism 45.

[0034] The beneficial effects of adopting the above-mentioned further technical solution are as follows: A gas flow meter is used to measure the experimental gas injection rate. A pressure sensor is used to measure the internal pressure of the sediment container and each pipeline. A weighing component is used to measure the mass of discharged brine and calculate the discharge flow rate. A gas pressure gauge is used to monitor pressure changes. The depressurized gas is connected to the first sediment container, the second sediment container, and the reference chamber through pipelines. This facilitates the user in obtaining pressure, flow rate, and other parameter data at different locations.

[0035] like Figure 1 As shown, further, a first displacement sensor 40 for measuring the displacement of the second compaction piston 34 and a second displacement sensor 41 for measuring the displacement of the first compaction piston 33 are installed on the top of the second sediment container 32. The second compaction piston 34 is located on one side of the top of the second sediment container 32, and the first compaction piston 33 is located on the other side of the top of the second sediment container 32. The first displacement sensor 40 is correspondingly arranged with the second compaction piston 34, and the second displacement sensor 41 is correspondingly arranged with the first compaction piston 33. A third displacement sensor 42 for measuring the displacement of the third compaction piston 44 is installed on the top of the first sediment container 31, and the third displacement sensor 42 is correspondingly arranged with the third compaction piston 44.

[0036] The beneficial effects of adopting the above-mentioned further technical solution are: the displacement sensor is used to measure the compaction stroke of the compaction piston in the sediment container, which makes it easier for users to obtain the stroke parameter data of the compaction piston, provide data support for the experiment, and improve the reliability of the experimental device.

[0037] like Figure 1As shown, it further includes: a data acquisition instrument 43, wherein the gas flow meter 23, the weighing component 30, the first pressure sensor 35, the second pressure sensor 36, the third pressure sensor 37, the fourth pressure sensor 38, the fifth pressure sensor 39, the first displacement sensor 40, the second displacement sensor 41, and the third displacement sensor 42 are all connected to the data acquisition instrument 43.

[0038] The beneficial effects of adopting the above-mentioned further technical solution are as follows: the data acquisition instrument is used to collect various data such as pressure, flow rate, and mass. The gas flow meter is placed after the gas pressure reducing valve, and the displacement sensor and pressure sensor are connected to the first sediment container and the second sediment container, respectively, with the other end connected to the data acquisition instrument. The data acquisition instrument is connected to a computer, and the computer is equipped with dedicated acquisition software for collecting and processing various data.

[0039] Pressure sensor: Pressure: 0~5MPa; Accuracy: 0.25%FS.

[0040] like Figure 1 As shown, the vacuum mechanism 45 further includes: a vacuum pressure gauge 25, a vacuum pump 26, a drying tank 27, and a buffer tank 28. The vacuum pump 26 is connected to the drying tank 27, the drying tank 27 is connected to the buffer tank 28, and the buffer tank 28 is connected to the first pipeline 46.

[0041] The beneficial effects of adopting the above-mentioned further technical solution are: the vacuum pump is connected to the sediment container to eliminate the influence of foreign gases, improve the accuracy of experimental data, and improve the stability and reliability of the experimental device.

[0042] like Figure 1 As shown, the first sediment container 31 is a cylindrical sediment container, and the second sediment container 32 is a U-shaped sediment container.

[0043] The beneficial effects of adopting the above-mentioned further technical solutions are as follows: the cylindrical and U-shaped sediment containers are used to simulate the cavity and load the sediment, brine, and gas used in the experiment. The setting of the compaction piston enables the sediment container to compact insoluble sediment.

[0044] Cylindrical sediment container: Internal dimensions: Material: Transparent acrylic; Pressure resistance: 5MPa; Capable of axial loading and compacting sediment; Compaction stroke: 225mm; U-shaped sediment container: Two cylindrical inner cavity dimensions: Center distance between two cylinders: 600mm; Material: transparent acrylic; Pressure resistance: 5MPa; Capable of axial loading to compact sediment; Compaction stroke: 225mm; Bottom circular channel dimensions: Material: Transparent acrylic; Pressure resistance: 5MPa; 316 stainless steel is used for connection at the elbow.

[0045] like Figure 1 As shown, further, the first pipeline 46 is equipped with a gas pressure reducing valve 20, a first valve 1, a second valve 2, a fifth valve 5, a sixth valve 6, a seventeenth valve 17, an eighteenth valve 18, and a nineteenth valve 19. The gas pressure reducing valve 20 is adjacent to the gas cylinder 21. The gas pressure reducing valve 20, the second valve 2, the seventeenth valve 17, the eighteenth valve 18, and the fifth valve 5 are sequentially installed on the first pipeline 46. The fifth valve 5 is adjacent to the first sediment container 31 and is connected to the first end of the first sediment container 31. The first valve 1 is connected to the first pipeline 46 between the gas pressure reducing valve 20 and the second valve 2. The sixth valve 6 is connected to the first pipeline 46 between the fifth valve 5 and the first sediment container 31. One end of the nineteenth valve 19 is connected to the first pipeline 46 between the second valve 2 and the seventeenth valve 17, and the other end of the nineteenth valve 19 is connected to the first pipeline 46 between the eighteenth valve 18 and the fifth valve 5.

[0046] The beneficial effects of adopting the above-mentioned further technical solution are: the gas pressure reducing valve can adjust the injected high-pressure gas to the pressure required for the experiment, ensuring experimental safety. The gas cylinder's pressure is adjusted to the required level through the gas pressure reducing valve. The depressurized gas is connected to the first sediment container, the second sediment container, and the reference chamber through pipelines. Valves are used to control the switching of each pipeline, allowing users to flexibly adjust the on / off state of different pipeline positions according to actual experimental needs and experimental objectives, thus improving the applicability of the experimental apparatus.

[0047] The valve can be a manual valve.

[0048] like Figure 1 As shown, further, a third pipeline 48 is connected to the first pipeline between the second valve 2 and the gas pressure reducing valve 20. The third pipeline 48 is connected to the first end of the second sediment container 32 through the seventh valve 7, the second end of the second sediment container 32 through the tenth valve 10, and the second end of the first sediment container 31 through the thirteenth valve 13. The third end of the second sediment container 32 is connected to the first pipeline 46 between the eighteenth valve 18 and the fifth valve 5 through the eighth valve 8, and the fourth end of the second sediment container 32 is connected to the first pipeline 46 between the eighteenth valve 18 and the fifth valve 5 through the eleventh valve 11.

[0049] The beneficial effects of adopting the above-mentioned further technical solution are: the valve is used to control the switching of each pipeline, which makes it convenient for users to flexibly adjust the on / off state of different positions of the pipeline according to the actual experimental needs and experimental objectives, thereby improving the applicability of the experimental device.

[0050] like Figure 1 As shown, the reference chamber 24 is further connected to the other end of the nineteenth valve 19 and the fifth valve 5 via a first pipeline 46, and the vacuum mechanism 45 is connected to the other end of the nineteenth valve 19 and the fifth valve 5 via a fourth valve 4.

[0051] The beneficial effects of adopting the above-mentioned further technical solution are: the valve is used to control the switching of each pipeline, which makes it convenient for users to flexibly adjust the on / off state of different positions of the pipeline according to the actual experimental needs and experimental objectives, thereby improving the applicability of the experimental device.

[0052] like Figure 1 As shown, further, the bottom of the second sediment container 32 is connected to the second pipeline 47 through the fifteenth valve 15, the bottom of the first sediment container 31 is connected to the second pipeline 47 through the sixteenth valve 16, the middle part of the second sediment container 32 is connected to the second pipeline 47 through the ninth valve 9, the fourth end of the second sediment container 32 is connected to the second pipeline 47 through the twelfth valve 12, and one end of the brine tank 29 is connected to the first pipeline 46 through the fourteenth valve 14.

[0053] The beneficial effects of adopting the above-mentioned further technical solution are: the valve is used to control the switching of each pipeline, which makes it convenient for users to flexibly adjust the on / off state of different positions of the pipeline according to the actual experimental needs and experimental objectives, thereby improving the applicability of the experimental device.

[0054] This invention provides an experimental device for gas injection and brine removal from salt cavern sediment, used to evaluate the gas storage capacity of salt cavern gas storage sediment, including experiments on the porosity of insoluble sediment accumulation, gas drive efficiency, and physical simulation experiments on different gas injection and brine removal methods (two injections and one removal, one injection and one removal, and brine removal from the bottom of a horizontal well).

[0055] The experimental apparatus for storing, injecting, and discharging brine from salt cavern sediment includes the following components: a gas pressure reducing valve, a cylindrical sediment container (first sediment container), a U-shaped sediment container (second sediment container), a reference chamber, a vacuum system (vacuum mechanism), a gas flow meter, a displacement sensor, a pressure sensor, an electronic scale (weighing component), a data acquisition module (data acquisition instrument), valves, pipe fittings, electrical components, an integrated equipment support frame, data acquisition software, and a computer. Specifically, the gas pressure reducing valve adjusts the injected high-pressure gas to the required experimental pressure, ensuring experimental safety. The cylindrical and U-shaped sediment containers simulate the cavity, loading the sediment, brine, and gas used in the experiment. The reference chamber measures the sediment porosity based on the principle of isothermal gas expansion. The vacuum system evacuates the sediment container. The gas flow meter measures the injection rate. The displacement sensor measures the compaction stroke. The pressure sensor measures the pressure inside the sediment container and each pipeline. The electronic scale measures the mass of discharged brine and calculates the discharge flow rate. The data acquisition module is mainly used to collect various data such as pressure, flow rate, and mass. Valves are mainly used for controlling the switching on and off of various pipelines.

[0056] The positional and connection relationships of each component are as follows: The gas cylinder's pressure is adjusted to the required level via a gas pressure reducing valve, and a gas pressure gauge is connected above the gas pressure reducing valve to monitor pressure changes; the reduced-pressure gas is connected to the cylindrical sediment container, U-shaped sediment container, and reference chamber via pipelines; the vacuum pump is connected to the cylindrical and U-shaped sediment containers to eliminate the influence of foreign gases; the gas flow meter is placed after the gas pressure reducing valve, and the displacement and pressure sensors are connected to the cylindrical and U-shaped sediment containers respectively, with the other end connected to the data acquisition module; the electronic scale is connected to the data acquisition module to monitor the quality of the discharged brine. Valves are installed on the pipelines connected to the cylindrical and U-shaped sediment containers; the data acquisition module is connected to a computer, which installs dedicated data acquisition software for data acquisition and processing; all accessories and equipment are integrated and installed on an integrated equipment bracket (not shown).

[0057] The device features both automatic and manual control, with data automatically acquired by computer. It can measure the gas storage capacity of sediment pores and the displacement efficiency of different brine discharge methods. Vacuum system: equipped with a vacuum pressure gauge, buffer tank, drying tank, and vacuum pump. Monitoring system: 1. Data acquisition instrument: used to acquire monitoring data from pressure sensors, flow rate, displacement, etc.; 2. Communication cable: transmits monitoring data from various sensors to the data acquisition card; 3. Data transmission line: transmits the monitoring data acquired by the acquisition card to the computer acquisition software for analysis; 4. Analysis host: computer; 5. Dedicated experimental software; 6. Process requirements: pipelines should be 1 / 4" diameter, made of 316 stainless steel, and withstand a pressure of 5MPa.

[0058] This invention can complete experiments on the porosity of insoluble sediment accumulation in salt cavern gas storage, gas drive efficiency, and physical simulation experiments on different gas injection and brine discharge methods (two injections and one discharge, one injection and one discharge, and brine discharge at the bottom of horizontal wells). The experimental results can provide guidance for improving the utilization rate of sediment space in salt cavern gas storage and significantly improve the economic efficiency of cavity construction in high insoluble salt mines.

[0059] The experimental method is described in detail below:

[0060] Experimental objective: To study the efficiency of sludge gas injection and brine removal in mining areas, given the high content of insoluble matter, and to provide the sludge porosity, gas storage porosity, and gas injection and brine removal efficiency.

[0061] I. Preparation of Sediment Samples

[0062] Based on the actual proportion of salt layers in the strata, insoluble interlayers and salt layer cores were selected and soaked in water to dissolve and swell some of the easily soluble mudstone. For insoluble and hard interlayers, the cores were cut into thin sections and broken to simulate the collapse of the interlayers.

[0063] II. Single-chamber sediment aeration and brine discharge experiment:

[0064] A portion of the sediment sample is separated according to the container volume, the total mass m of the sediment is measured, and the sediment is filled into the sediment container. The volume V of the sediment filled into the container is measured.

[0065] After connecting the experimental apparatus, measure the porosity of the dried sediment: Inject high-pressure gas into the reference chamber and measure the injection pressure P1. Then open the sediment chamber valve (fifth valve) to connect the reference chamber and the first sediment container. After equilibrium is reached, measure the equilibrium pressure P2. Calculate the sediment porosity.

[0066] Prepare saturated brine, with the volume of saturated brine accounting for approximately 60% of the apparent volume of the sediment, and measure the mass concentration of the saturated brine.

[0067] The sediment is evacuated to -0.1 MPa, and then saturated brine is drawn in from the bottom. The mass and volume of the saturated brine before and after the drawing in are recorded, and the volume of brine drawn into the sediment is calculated. The porosity of the sediment solution can then be calculated.

[0068] Slowly open the gas pressure reducing valve, the second valve, the seventeenth valve, the eighteenth valve, and the fifth valve on the gas injection channel. The gas injection pressure can be set to 0.1-0.2 MPa.

[0069] After the pressure is balanced, slowly open the sixteenth valve and set the brine discharge flow rate to 20-30 ml / min.

[0070] During the aeration and brine discharge process, the mass of the discharged brine is obtained from the electronic scale, the volume of the discharged brine is calculated, and the experiment is stopped when bubbles appear at the discharge port.

[0071] The porosity of the gas storage can be calculated using the volume of discharged brine. Alternatively, the porosity can be measured using a standard-volume steel cylinder.

[0072] Then open the thirteenth valve to apply a compaction pressure of 0.5 MPa to the top of the sediment container, push the compaction piston downward, stabilize the pressure for 20 minutes, record the piston displacement distance through the third displacement sensor, and calculate the apparent volume of the compacted sediment.

[0073] Once again, saturated brine is introduced from the bottom of the sediment. The volume of brine entering is measured, and the total water content in the sediment can be calculated, as well as the total porosity.

[0074] Continue injecting gas and draining the brine.

[0075] III. Experiment on U-shaped cavity with two injection points and one drainage point for sediment injection and brine removal

[0076] Measure the total mass m of the sediment, fill it into the U-shaped sediment container (second sediment container), and measure the volume V of the sediment after filling.

[0077] After connecting the experimental instruments, measure the porosity of the dried sediment: inject high-pressure gas into the reference chamber and measure the injection pressure P1. Then open the eighth and eleventh valves of the U-shaped sediment chamber to connect the reference chamber and the second sediment container. After balancing, measure the balancing pressure P2 and calculate the sediment porosity.

[0078] The sediment is evacuated to -0.1 MPa, and then saturated brine is drawn in through the fifteenth valve at the lowest inlet of the horizontal channel. The mass and volume of the saturated brine before and after the drawing in are recorded, and the volume of brine drawn into the sediment is calculated. The total porosity of the sediment solution can then be calculated.

[0079] Slowly open the gas pressure reducing valve, the second valve, the seventeenth valve, the eighteenth valve, the eighth valve, and the eleventh valve on the gas injection channel (first pipeline). The gas injection pressure can be set to 0.1-0.2MPa.

[0080] First, inject air and drain brine from the top of the horizontal channel. At the same time, inject air from the top of the cylinders on both sides of the U-shaped cavity. Open the brine drain valve (ninth valve) at the top of the horizontal channel and set the brine drain flow rate to 20-30 ml / min.

[0081] During the gas injection and brine discharge process, the volume of discharged brine is measured, and the experiment is stopped when bubbles appear at the discharge port. The gas storage volume, gas storage porosity, and brine discharge efficiency are calculated.

[0082] Once gas is observed in the discharged brine, open the bottom discharge valve (valve number fifteen) to continue injecting gas and discharging brine, and measure the volume of the second discharged brine. Calculate the gas storage volume, gas storage porosity, and discharge efficiency. Compare the two results to calculate the additional porosity volume utilized.

[0083] First, release the low-pressure gas inside the sediment. Then, open the seventh and tenth valves and apply a compaction pressure of 0.5 MPa to the top of the first and second compaction pistons. Record the movement distance of the first and second compaction pistons and calculate the apparent volume of the sediment after compaction.

[0084] After vacuuming, brine is drawn back in through the fifteenth valve at the bottom, and the volume of the brine is recorded. Based on the volume of the brine recorded in the above steps, the total porosity of the sediment is calculated.

[0085] A two-stage injection and one-stage discharge test of sediment under a compaction pressure of 0.5 MPa was conducted.

[0086] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A salt cavern sediment gas storage gas injection halogen discharge experimental device, characterized in that, include: The system comprises a gas cylinder (21), a reference chamber (24) for measuring the porosity of sediment, a brine tank (29), a first sediment container (31) for loading sediment, a second sediment container (32) for loading sediment, a vacuum mechanism for vacuum treatment of the first sediment container (31) and the second sediment container (32), a first compaction piston (33), a second compaction piston (34), and a third compaction piston (44). The gas cylinder (21) is connected to the first sediment container (31) via a first pipeline (46). The reference chamber (24), one end of the brine tank (29), the vacuum mechanism, and the second sediment container (32) are all connected to the first pipeline (46). The other end of the brine tank (29) is connected to the first sediment container (31) and the second sediment container (32) via a second pipeline (47). The first compaction piston (33) and the second compaction piston (34) are slidably installed in the second sediment container (32). The third compaction piston (44) is slidably installed in the first sediment container (31); a gas pressure gauge (22) and a gas flow meter (23) are provided on the first pipeline (46) between the gas cylinder (21) and the reference chamber (24). The gas pressure gauge (22) is adjacent to the gas cylinder (21), and the gas flow meter (23) is adjacent to the reference chamber (24). A weighing component (30) for measuring the weight of the brine tank (29) is installed at the bottom. A first pressure sensor (35) is connected to one side of the top of the second sediment container (32), and a second pressure sensor (36) is connected to the other side of the top of the second sediment container (32). A third pressure sensor (37) is connected to the top of the first sediment container (31). A fourth pressure sensor (38) is connected to the top of the reference chamber (24). A fifth pressure sensor (39) is installed on the first pipeline (46) between the reference chamber (24) and the vacuum mechanism.

2. The experimental device for gas injection and brine discharge in salt caverns with sediments according to claim 1, characterized in that, The top of the second sediment container (32) is equipped with a first displacement sensor (40) for measuring the displacement of the second compaction piston (34) and a second displacement sensor (41) for measuring the displacement of the first compaction piston (33). The second compaction piston (34) is located on one side of the top of the second sediment container (32), and the first compaction piston (33) is located on the other side of the top of the second sediment container (32). The first displacement sensor (40) is correspondingly set with the second compaction piston (34), and the second displacement sensor (41) is correspondingly set with the first compaction piston (33). The top of the first sediment container (31) is equipped with a third displacement sensor (42) for measuring the displacement of the third compaction piston (44). The third displacement sensor (42) is correspondingly set with the third compaction piston (44).

3. The experimental device for gas storage, injection and brine discharge in salt caverns according to claim 2, characterized in that, Also includes: The data acquisition instrument (43), the gas flow meter (23), the weighing component (30), the first pressure sensor (35), the second pressure sensor (36), the third pressure sensor (37), the fourth pressure sensor (38), the fifth pressure sensor (39), the first displacement sensor (40), the second displacement sensor (41), and the third displacement sensor (42) are all connected to the data acquisition instrument (43).

4. The experimental device for storing, injecting, and discharging brine from salt cavern sediment according to claim 1, characterized in that, The vacuum mechanism includes: a vacuum pressure gauge (25), a vacuum pump (26), a drying tank (27), and a buffer tank (28). The vacuum pump (26) is connected to the drying tank (27), the drying tank (27) is connected to the buffer tank (28), and the buffer tank (28) is connected to the first pipeline (46).

5. The experimental device for storing, injecting, and discharging brine from salt cavern sediment according to claim 1, characterized in that, The first sediment container (31) is a cylindrical sediment container, and the second sediment container (32) is a U-shaped sediment container.

6. The experimental device for storing, injecting, and discharging brine from salt cavern sediment according to claim 1, characterized in that, The first pipeline (46) is equipped with a gas pressure reducing valve (20), a first valve (1), a second valve (2), a fifth valve (5), a sixth valve (6), a seventeenth valve (17), an eighteenth valve (18), and a nineteenth valve (19). The gas pressure reducing valve (20) is adjacent to the gas cylinder (21). The gas pressure reducing valve (20), the second valve (2), the seventeenth valve (17), the eighteenth valve (18), and the fifth valve (5) are sequentially installed on the first pipeline (46). The fifth valve (5) is adjacent to the first sediment container (31). The fifth valve (5) is connected to the first sediment container (31). The first end of the first sediment container (31) is connected to the first pipeline (46) between the first valve (1) and the gas pressure reducing valve (20) and the second valve (2), the sixth valve (6) is connected to the first pipeline (46) between the fifth valve (5) and the first sediment container (31), one end of the nineteenth valve (19) is connected to the first pipeline (46) between the second valve (2) and the seventeenth valve (17), and the other end of the nineteenth valve (19) is connected to the first pipeline (46) between the eighteenth valve (18) and the fifth valve (5).

7. The experimental device for storing, injecting, and discharging brine from salt cavern sediment according to claim 6, characterized in that, A third pipeline (48) is connected to the first pipeline (46) between the second valve (2) and the gas pressure reducing valve (20). The third pipeline (48) is connected to the first end of the second sediment container (32) through the seventh valve (7), the third pipeline (48) is connected to the second end of the second sediment container (32) through the tenth valve (10), and the third pipeline (48) is connected to the second end of the first sediment container (31) through the thirteenth valve (13). The third end of the second sediment container (32) is connected to the first pipeline (46) between the eighteenth valve (18) and the fifth valve (5) through the eighth valve (8), and the fourth end of the second sediment container (32) is connected to the first pipeline (46) between the eighteenth valve (18) and the fifth valve (5) through the eleventh valve (11).

8. The experimental device for storing, injecting, and discharging brine from salt cavern sediment according to claim 6, characterized in that, The reference chamber (24) is connected to the other end of the nineteenth valve (19) and the fifth valve (5) via a first pipeline (46) through a third valve (3), and the vacuum mechanism is connected to the other end of the nineteenth valve (19) and the fifth valve (5) via a fourth valve (4).

9. The experimental device for storing, injecting, and discharging brine from salt cavern sediment according to claim 1, characterized in that, The bottom of the second sediment container (32) is connected to the second pipeline (47) through the fifteenth valve (15), the bottom of the first sediment container (31) is connected to the second pipeline (47) through the sixteenth valve (16), the middle part of the second sediment container (32) is connected to the second pipeline (47) through the ninth valve (9), the fourth end of the second sediment container (32) is connected to the second pipeline (47) through the twelfth valve (12), and one end of the brine tank (29) is connected to the first pipeline (46) through the fourteenth valve (14).

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