An experimental apparatus and simulation method for natural gas hydrate eruptions

Abstract

The embodiment of the present application discloses an experimental device and a simulation experiment method for natural gas hydrate eruption, and the experimental device comprises: an eruption simulation box, a sample preparation system, an eruption medium simulation system, a monitoring system, a data collection and processing system, the eruption medium simulation system comprises an eruption medium storage mechanism and an eruption medium providing mechanism which are sequentially communicated with the eruption simulation box, and a parameter adjusting mechanism for controlling preset parameter values of the eruption medium in the eruption medium storage mechanism; and the preset parameter values of the eruption medium at least include a pressure value and an eruption duration of the eruption medium. The present application can adjust environmental parameters, accurately control the pressure and the duration of the eruption medium according to the preset parameter values on the premise of maximizing the simulation of variable environmental parameters, and maximize the simulation of the eruption process to restore the actual eruption situation and improve the simulation accuracy.

Description

Technical Field

[0001] This invention relates to the field of natural gas hydrate extraction technology, specifically to an experimental apparatus and simulation method for natural gas hydrate eruptions. Background Technology

[0002] Natural gas hydrates are a highly promising strategic resource. With far less pollution than coal and oil, and huge reserves, they are internationally recognized as a replacement energy source for oil and other resources.

[0003] During its extraction, natural gas hydrates, under temperature or pressure disturbances, decompose from a solid phase into water and methane gas, transforming the originally continuous hydrate-bearing formation into decomposed and undecomposed zones. During this decomposition process, the soil gradually softens, leading to the accumulation of pore gas pressure under conditions of slow fluid pressure dissipation. Therefore, hydrate decomposition can cause deformation and damage to local soil layers and wellbore structures, and even lead to large-scale submarine landslides and methane leaks. The release and accumulation of methane gas from the hydrate reservoir causes overlying strata to uplift, ultimately resulting in a gas-carrying sediment eruption that forms a deep crater.

[0004] Current research on the decomposition and eruption of natural gas hydrates has many shortcomings. For example, it is difficult to capture the geometric characteristics of soil failure and critical conditions, as well as other solid behaviors. It also cannot describe the new mechanical behaviors of multi-interface formation and gas-liquid-solid three-phase flow development during the gas eruption process. At the same time, existing experimental devices and methods are insufficient to comprehensively and accurately simulate and study the critical conditions and multiphase flow processes of hydrate-bearing eruptions, thus failing to meet the development needs of efficient hydrate extraction technologies. Summary of the Invention

[0005] Therefore, embodiments of the present invention provide an experimental apparatus and simulation method for natural gas hydrate eruption. Under the premise of being able to adjust environmental parameters to maximize the simulation of variable environmental parameters, the pressure, temperature and duration of the eruption medium are further precisely controlled according to preset parameter values, so that the eruption process can reproduce the actual eruption situation to the greatest extent and improve the accuracy of the simulation.

[0006] To achieve the above objectives, the embodiments of the present invention provide the following technical solutions:

[0007] In one aspect of the present invention, an experimental apparatus for natural gas hydrate eruption is provided, comprising:

[0008] The eruption simulation chamber has a cavity for holding samples that simulate an eruption environment;

[0009] A sample preparation system, at least partially located in the receiving cavity, is used to adjust the sample in the receiving cavity to a preset simulated value;

[0010] An eruption medium simulation system, connected to the eruption simulation chamber, is used to provide an eruption medium with preset parameter values ​​to the eruption simulation chamber;

[0011] A monitoring system is used to dynamically monitor the eruption process in the eruption simulation chamber;

[0012] The data collection and processing system is used to collect and process the data monitored by the monitoring system; among which,

[0013] The eruption medium simulation system includes at least an eruption medium storage mechanism and an eruption medium supply mechanism sequentially connected to the eruption simulation box, as well as a parameter adjustment mechanism for controlling the preset parameter values ​​of the eruption medium in the eruption medium storage mechanism; and,

[0014] The preset parameter values ​​of the ejection medium include at least the pressure value of the ejection medium and the ejection duration.

[0015] As a preferred embodiment of the present invention, the sample preparation system includes at least a vibration table that contacts the eruption simulation chamber and is capable of oscillating the eruption simulation chamber, and a leveling structure that is movably disposed in the receiving cavity along the extending direction of the receiving cavity.

[0016] The leveling structure is used to level the sample surface in the receiving cavity.

[0017] As a preferred embodiment of the present invention, the monitoring system includes at least a high-speed camera for capturing images of the eruption process in the eruption simulation chamber, and a pressure sensor disposed on the inner wall of the eruption simulation chamber.

[0018] As a preferred embodiment of the present invention, the monitoring system further includes a light source for providing observation light to the eruption simulation chamber.

[0019] As a preferred embodiment of the present invention, a gas valve is provided between the ejection medium storage mechanism and the ejection medium supply mechanism, and a control device is provided to control the output parameters of the ejection medium in the ejection medium storage mechanism by controlling the gas valve;

[0020] The parameter adjustment mechanism includes at least an eruption duration control unit disposed between the eruption simulation chamber and the eruption medium storage mechanism. The eruption duration control unit is used to control the eruption duration of the eruption medium introduced into the eruption simulation chamber by the eruption medium storage mechanism.

[0021] As a preferred embodiment of the present invention, the eruption duration control unit includes a solenoid valve connected between the eruption medium storage mechanism and the eruption simulation box, a time relay electrically connected to the solenoid valve, and a signal triggering device electrically connected to the time relay, wherein the time relay triggers the opening and closing of the solenoid valve according to the signal triggering device.

[0022] As a preferred embodiment of the present invention, the parameter adjustment mechanism further includes a temperature control unit for adjusting the temperature of the ejection medium in the ejection medium storage mechanism, and the temperature control unit is electrically connected to the signal triggering device.

[0023] As a preferred embodiment of the present invention, the temperature control unit includes a multi-stage temperature control structure arranged sequentially from the ejection medium supply mechanism to the ejection medium storage mechanism, wherein the temperature of the multi-stage temperature control structure increases or decreases progressively.

[0024] As a preferred embodiment of the present invention, the ejection medium storage mechanism is further provided with a pressure detection feedback unit, which is used to monitor the gas pressure in the ejection medium storage mechanism and feed it back to the signal triggering device.

[0025] In another aspect of the invention, a method for simulating natural gas hydrate eruption is also provided, employing the experimental apparatus for natural gas hydrate eruption as described above. The method for simulating natural gas hydrate eruption is as follows: Figure 5 As shown, it includes:

[0026] S100. Construct a simulated eruption environment with preset simulation values ​​in the eruption simulation chamber;

[0027] S200, Adjust the pressure of the ejection medium and the ejection duration to reach their respective preset parameter values;

[0028] S300: Open the eruption medium supply mechanism until the eruption medium used for eruption reaches at least part of the preset parameter values, trigger the eruption medium to simulate eruption in the eruption simulation box, and monitor the eruption process through the monitoring system;

[0029] S400: Collect monitoring data from the monitoring system.

[0030] As a preferred embodiment of the present invention, the construction method in step S100 specifically includes:

[0031] S101. Mix silty clay with water until the moisture content is 15%-20% to obtain a soil sample;

[0032] S102. Place the obtained soil sample in the eruption simulation chamber and vibrate to compact it until the void ratio of the soil sample is no greater than 0.6. Then level the soil sample to obtain the soil sample layer.

[0033] S103. Pour simulated seawater into the eruption simulation chamber until the liquid level is 3 / 5-4 / 5 of the chamber's height, thus creating a simulated eruption environment.

[0034] In a preferred embodiment of the present invention, in step S300, the simulated eruption process includes multiple intermittent eruptions at intervals, and the preset parameter values ​​for each intermittent eruption are not exactly the same; and,

[0035] The preset parameter values ​​in step S200 include multiple sets of pressure values ​​and eruption durations of the eruption medium, with each set of pressure values ​​and eruption durations corresponding to one intermittent eruption.

[0036] As a preferred embodiment of the present invention, the preset pressure values ​​of adjacent intermittent eruptions increase or decrease in a gradient manner.

[0037] As a preferred embodiment of the present invention, the preset parameter value in step S200 also includes the temperature of the ejection medium.

[0038] As a preferred embodiment of the present invention, in step S300, when the pressure value and the ejection temperature of the ejection medium both reach the preset parameter range, the ejection medium is triggered to eject.

[0039] The embodiments of the present invention have the following advantages:

[0040] This invention further incorporates a dynamically adjustable sample preparation system within the eruption simulation chamber, enabling the simulation of natural gas hydrates and their eruption environment that more closely resembles reality. Gas eruption occurs within a dedicated eruption simulation chamber, allowing for precise control over soil sample compaction, pressure, and eruption duration, ensuring the quality and stability of the experimental samples and laying the foundation for the accuracy of subsequent experiments. Simultaneously, a monitoring system enables dynamic capture of the entire eruption process. Furthermore, by separating the eruption medium storage and supply mechanisms and linking them with the parameter adjustment mechanism, precise control of key parameters such as pressure loading rate and eruption duration is achieved.

[0041] Based on the above settings, the effects of different pressure gradients on the eruption flow pattern, soil failure mode, and particle migration law of natural gas hydrates can be verified, providing experimental basis for the design of safe pressure windows for deep-sea drilling and theoretical basis for wellbore stability analysis and blowout prevention device design for seabed hydrate extraction. Attached Figure Description

[0042] To more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are merely exemplary, and those skilled in the art can derive other embodiments based on the provided drawings without creative effort.

[0043] The structures, proportions, sizes, etc. illustrated in this specification are only for the purpose of assisting those skilled in the art in understanding and reading the content disclosed herein, and are not intended to limit the conditions under which the present invention can be implemented. Therefore, they have no substantial technical significance. Any modifications to the structure, changes in the proportions, or adjustments to the size, without affecting the effects and objectives that the present invention can produce, should still fall within the scope of the technical content disclosed in the present invention.

[0044] Figure 1 This is a schematic diagram of the experimental apparatus for natural gas hydrate eruption provided in an embodiment of the present invention;

[0045] Figure 2 This is a schematic diagram of the eruption simulation chamber and sample preparation system provided in an embodiment of the present invention;

[0046] Figure 3 A side view of the eruption simulation chamber and sample preparation system provided in an embodiment of the present invention;

[0047] Figure 4 This is a partial structural schematic diagram of another eruption medium simulation system provided in an embodiment of the present invention;

[0048] Figure 5 A flowchart of the simulation method provided in an embodiment of the present invention.

[0049] In the picture:

[0050] 1-Ejection simulation chamber; 2-Sample preparation system; 3-Ejection medium simulation system; 4-Monitoring system; 5-Data collection and processing system; 6-Soil sample;

[0051] 11-Receiving cavity;

[0052] 21-Vibration table; 22-Scraper; 23-Guide rail;

[0053] 31-Ejection medium storage mechanism; 32-Ejection medium supply mechanism; 33-Gas valve; 34-Ejection duration control unit; 35-Multi-stage temperature control structure;

[0054] 41-Pressure sensor; 42-High-speed camera; 43-Light source. Detailed Implementation

[0055] The following specific embodiments illustrate the implementation of the present invention. Those skilled in the art can easily understand other advantages and effects of the present invention from the content disclosed in this specification. Obviously, the described embodiments are only some, not all, of the embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0056] like Figure 1 As shown, this invention provides an experimental apparatus for the eruption of natural gas hydrates, specifically comprising:

[0057] Eruption Simulation Chamber 1: This is the reaction site for the entire experiment. It has a containment cavity 11, which can be used to place the soil sample 6 simulating the eruption environment and construct the overall eruption environment. Specifically, it can be a transparent chamber structure. For example, for easy observation, the main body of the chamber can be made of transparent high-strength plexiglass (thickness ≥ 20 mm) to ensure experimental safety and facilitate observation of the internal gas-liquid-solid three-phase flow phenomena. The dimensions are length × width × height, which can be specifically selected as 1.0 m × 0.5 m × 1.0 m. It should be noted that the dimensions are not limited to these, and those skilled in the art can design the dimensions according to the experimental requirements. Multiple sensor interfaces are reserved on the side wall of the chamber for installing pressure sensors 41 to measure the pressure inside the chamber throughout the eruption process. In a more specific embodiment, the sensor interfaces can be arranged in groups of 20 cm along the height of the chamber for installing pressure sensors 41 (again, the specific arrangement of the position and number of pressure sensors 41 can be selected according to the actual situation and is not limited to this in actual operation). The gas inlet is located at the center of the bottom of the chamber and is connected to the pressure box (i.e., the ejection medium storage mechanism 31) via a flange, so that the gas ejection medium in the pressure box can enter the ejection simulation box 1 to complete the ejection.

[0058] Sample preparation system 2: such as Figure 2 and Figure 3 As shown, a sample is used to prepare a simulated underwater solid-liquid environment for the gas decomposition and eruption of natural gas hydrates. Specifically, the pre-prepared overburden soil sample 6 is placed on a vibration table 21 (driven by a variable frequency motor with a vibration frequency range of 0-50Hz) and vibrated to compact it. The surface of the soil sample 6 is then uniformly leveled using a leveling structure (for example, an adjustable scraper 22 can be selected, which is moved horizontally along the eruption simulation box 1 by setting a guide rail 23) so that the surface flatness error of the leveled soil sample 6 is ≤1mm.

[0059] Ejection medium simulation system 3: It has an ejection medium storage mechanism 31 (i.e., pressure box) and an ejection medium supply mechanism 32 (which can be a high-pressure gas tank) connected in sequence, and is also equipped with a parameter adjustment mechanism to adjust the parameters of the ejection medium in the pressure box.

[0060] In the first scenario, parameter adjustment includes the pressure value of the ejection medium and the ejection duration. In this case, the pressure value of the ejection medium can be directly achieved through the cooperation of the pressure box and the high-pressure gas tank. Specifically, in one embodiment, the high-pressure gas tank stores high-pressure nitrogen (pressure range 0-10 MPa) and is connected to gas valve 33 (specifically, a pressure regulating valve) via a stainless steel pipeline; the pressure regulating valve receives the control signal from the function generator and precisely adjusts the output gas pressure (accuracy ±0.01 MPa); the pressure box has a volume of 5L and a built-in porous buffer layer (made of sintered metal) to stabilize the gas flow and reduce pressure fluctuations; the function generator is a multi-channel waveform generator with a preset pressure loading curve, used to output control signals to the pressure regulating valve to adjust the gas input pressure (it should be noted that this invention is not limited to using only a function generator as a specific control device; any suitable control device capable of controlling the pressure regulating valve and adjusting the output gas pressure can be used). Furthermore, a pressure gauge and a pressure reducing valve can be installed at the outlet of the high-pressure gas tank. Combined with the pressure box, this makes the parameters of the eruption medium supplied by the entire eruption medium simulation system 3 to the eruption simulation box 1 more controllable, improving the accuracy of the eruption simulation process. The control of the eruption duration can be achieved by a solenoid valve and a time relay connected to the eruption simulation box 1. For example, in a specific embodiment, the solenoid valve can be a high-pressure direct-acting solenoid valve (pressure resistance ≥15MPa, response time ≤10ms), which is installed in the pipeline between the pressure box and the eruption simulation box 1. After receiving a trigger signal, it quickly opens / closes to control the injection and cut-off of high-pressure gas into the eruption simulation box 1, thereby achieving the regulation of the eruption duration. The time relay can be a digital programmable time relay (time resolution 0.01s, error ±0.1%), which is linked to the solenoid valve and the function generator through a signal line. Its function is to be able to set the opening duration of the solenoid valve (adjustable from 0.1-5.0s) and to trigger the eruption after receiving the threshold signal from the pressure sensor 41. That is, the pressure sensor 41 here transmits the pressure signal to the signal triggering device. When the pressure signal sensed by the signal triggering device reaches the threshold, the signal triggering device controls the time relay to complete the eruption according to the preset eruption duration.

[0061] In the second scenario, parameter adjustment includes not only the pressure and duration of the ejection medium but also its temperature. In this case, in addition to the structure present in the first scenario, a temperature control unit capable of regulating the temperature of the ejection medium needs to be further arranged in the gas passages of the pressure box and high-pressure gas tank, and / or on the pressure box. In this case, the temperature signal from the temperature control unit is also transmitted to the signal triggering device. That is, both the pressure value (feedback to the signal triggering device via a pressure detection feedback unit) and the temperature value of the gas in the pressure box are fed back to the signal triggering device. The signal triggering device (for example, in this invention, it can be implemented using a computer) adjusts according to the difference between the pressure and temperature values ​​and preset parameter values, so that once both the pressure and temperature values ​​reach the preset parameter range, an ejection signal is emitted. It should be noted that when the pressure and temperature values ​​differ from the preset parameter values, the adjustment can be performed in a manner understandable to those skilled in the art. For example, when the temperature value is not within the preset parameter range, temperature adjustment can be achieved by controlling the temperature of the temperature control unit. Meanwhile, the gas valve 33 here can also be a two-way valve, so that during temperature changes, if the gas pressure is above the preset parameter range, a portion of the ejected gas from the pressure box can be introduced into the high-pressure gas tank through the two-way valve, ensuring dynamic control of the pressure and temperature values, and ultimately keeping both within the preset parameter range. The preset parameter ranges for pressure and temperature can be selected according to actual conditions, which will not be elaborated here. Furthermore, to reduce the problem of sudden and excessive temperature changes during temperature regulation and minimize reverse flow of the two-way valve, the temperature control unit here can adopt a multi-stage temperature control structure 35, with the temperature increasing or decreasing progressively until the temperature of the temperature control structure closest to or located on the pressure box is within the preset parameter range. Figure 4 As shown, the multi-stage temperature control structure 35 has three stages. Of course, this is only a specific embodiment. The present invention is not limited to this specific three-stage temperature control structure. Furthermore, the temperature control structure can also be partially set in the pressure box. In addition, adjacent temperature control structures can be set at intervals or continuously, which will not be elaborated here.

[0062] It needs to be explained that in the first case, since the gas introduction is preset, the pressure of the gas in the pressure box is relatively controllable after the gas is introduced, and a pressure detection feedback unit does not need to be installed in the pressure box. However, in the second case, since temperature is introduced, it has a certain variability effect on the pressure. Therefore, in the second case, an additional pressure detection feedback unit is needed to monitor and provide feedback on the pressure of the gas in the pressure box.

[0063] Monitoring System 4 includes a high-speed camera 42 and a pressure sensor 41 (as mentioned above, located in the eruption simulation chamber 1). Multiple high-speed cameras 42 can be installed, for example, at the front and side angles of the natural gas hydrate decomposition pipeline (more high-speed cameras 42 can also be installed at other angles). They can capture the particle decomposition process, flow pattern changes, and bed expansion from all angles, with a frame rate of over 5000 frames per second, clearly capturing the flow and reaction details inside the natural gas hydrate decomposition pipeline, providing intuitive image data for subsequent analysis. Simultaneously, observation light is provided to the eruption simulation chamber 1 through a light source 43. For example, a ring-shaped LED cold light source 43 can be used to avoid heat interference with the flow field during the experiment. Pressure sensors 41 (range 0-5 MPa, accuracy ±0.1%) can be arranged in groups every 20 cm along the height of the chamber to monitor the pressure and pressure gradient changes inside the natural gas hydrate eruption.

[0064] Data collection and processing system 5: Connected to the aforementioned eruption medium simulation system 3, high-speed camera 42, and pressure sensor 41, it uses a high-speed data acquisition card and professional data processing software to collect, store, and process experimental data in real time, enabling data visualization and analysis, and facilitating rapid acquisition and analysis of experimental results. Data collection and recording can also be accomplished using a computer 5 with data analysis and processing capabilities.

[0065] The following section provides further explanation using specific simulation methods.

[0066] Step 1, Sample Preparation: Silty clay (particle size ≤ 0.075 mm) from the seabed hydrate distribution area was selected as the sedimentary framework for natural gas hydrate synthesis. The silty clay was mixed with distilled water to form a soil sample 6 with a specific moisture content, which was placed in the eruption simulation chamber 1. The moisture content of soil sample 6 was controlled between 15% and 25%. The soil sample 6 was vibrated and compacted uniformly using the vibration table 21 in the sample preparation system 2 for ≥ 30 minutes, resulting in a void ratio ≤ 0.6 after compaction (for example, in a specific operation, the vibration frequency was 35 Hz, the amplitude was 4 mm, the time was 40 minutes, and the void ratio after compaction was 0.53). The surface of soil sample 6 was then leveled using a leveling structure until the surface flatness error was ≤ 1 mm.

[0067] Step 2, Eruption Simulation Experiment: After leveling the sample prepared in the pre-eruption simulation chamber 1, add salt water to a certain height (the salt water should simulate the water parameters under actual conditions as much as possible, and the liquid level is preferably about 2 / 3 of the chamber height. For example, in a specific embodiment, the salt water concentration is 3.5% NaCl solution, and the liquid level is 1.5m); the eruption duration control unit 34 sets the time through a function generator using a custom Matlab program, which is adjustable from 0.01 to 5s. The pressure is controlled by adjusting the preset pressure parameter value by the pressure regulating valve, and the gas... After the gas is fed into the pressure box, the high-pressure gas tank is closed; the monitoring system 4 measures and records the data; after the solenoid valve connected to the pressure box is opened, the high-pressure gas is fed into the eruption simulation box 1 from the pressure box; the high-speed camera 42 of the monitoring system 4 is used to record the flow process of the gas-liquid-solid three phases and the soil damage characteristics in the eruption simulation box 1 during the gas eruption, and the flow pattern changes of the gas-liquid-solid three phases are recorded; the pressure sensor 41 is used to collect the gas pressure change information during the eruption process; the data collection and processing system 5 (for example, a computer) analyzes the impact of the eruption process on soil damage and particle height expansion.

[0068] In step 2, the eruption process is a multi-gradient eruption, for example, it can be divided into three eruptions: a low-pressure group, a medium-pressure group, and a high-pressure group. In a specific embodiment, the eruption control parameters are set as follows: pressure gradient: 1.5MPa (low-pressure group), 2.5MPa (medium-pressure group), 3.5MPa (high-pressure group); solenoid valve opening time: 1.0s; trigger threshold: 1.5MPa (low-pressure group), 2.0MPa (medium-pressure group), 2.5MPa (high-pressure group). The measurement system is configured with a high-speed camera 42 at a frame rate of 2000fps (local flow field capture); and a pressure sensor 41 with a sampling rate of 2kHz. In specific operation, pressure loading and eruption triggering are set into a stepped pressure loading curve by a function generator: low-pressure group: 0.15MPa per stage, 15s interval; high-pressure group: 0.3MPa per stage, 5s interval; when the pressure reaches the preset threshold, a time relay triggers the solenoid valve to open for 1.0s. A high-speed camera 42 synchronously acquires data to record the evolution of the eruption flow pattern; a pressure sensor 41 monitors the dynamic changes in pressure inside the chamber.

[0069] The sample preparation system 2 of this invention uses silty clay from the seabed hydrate distribution area as the raw material for soil sample 6, and prepares it using a specific method of the sample preparation system 2 to simulate a hydrate sample that is closer to reality. The gas eruption is carried out in a special eruption simulation chamber 1, and the compaction, pressure and eruption duration of soil sample 6 are precisely controlled within a certain range, ensuring the quality and stability of the experimental sample and laying the foundation for the accuracy of subsequent experiments.

[0070] The efficient setup of the high-speed camera 42 allows for comprehensive and clear capture of instantaneous details such as the particle eruption process, flow pattern changes, and bed expansion. Through pressure gradient control and a visualization chamber design, the coupling effect of the gas-liquid-solid three-phase flow after hydrate decomposition and eruption is accurately reproduced, especially the dynamic process of gas breaking through the overlying soil layer. Furthermore, the high spatiotemporal resolution measurement system can quantify the flow pattern transformation, particle migration, and energy dissipation mechanisms during the eruption process.

[0071] The eruption medium simulation system 3 of the present invention further achieves precise control of key parameters such as pressure loading rate and eruption duration by linking a time relay with a function generator.

[0072] Meanwhile, based on the separate design of the eruption medium storage mechanism 31 and the eruption medium supply mechanism 32 in the eruption medium simulation system 3, gradient experiments with adjustable parameters such as pressure can be carried out. The experimental data can verify the influence of different pressure gradients on the hydrate eruption flow pattern, soil failure mode and particle migration law, providing experimental basis for the design of safe pressure window for deep-sea drilling, and providing theoretical basis for the stability analysis of wellbore for seabed hydrate mining and the design of blowout prevention devices.

[0073] Based on this, this invention focuses on indoor gas-liquid-solid three-phase flow experiments simulating natural gas hydrate extraction, which can overcome the shortcomings of existing technologies in studying multiphase flow processes related to hydrate decomposition. Compared with traditional experimental setups, this invention can more accurately and comprehensively simulate and study the relevant processes, providing strong support for the development of efficient natural gas hydrate extraction technologies.

[0074] Although the present invention has been described in detail above with general descriptions and specific embodiments, modifications or improvements can be made to it, which will be obvious to those skilled in the art. Therefore, all such modifications or improvements made without departing from the spirit of the present invention fall within the scope of protection claimed by the present invention.

Claims

1. An experimental apparatus for the eruption of natural gas hydrates, characterized in that, include: The eruption simulation chamber (1) has a cavity (11) for holding samples in a simulated eruption environment. The sample preparation system (2), at least partially located in the receiving cavity (11), is used to adjust the sample in the receiving cavity (11) to a preset simulated value; The eruption medium simulation system (3) is connected to the eruption simulation box (1) and is used to provide the eruption medium with preset parameter values ​​to the eruption simulation box (1); The monitoring system (4) is used to dynamically monitor the eruption process in the eruption simulation box (1); The data collection and processing system (5) is used to collect and process the data monitored by the monitoring system (4); wherein, The eruption medium simulation system (3) includes at least an eruption medium storage mechanism (31) and an eruption medium supply mechanism (32) sequentially connected to the eruption simulation box (1), and a parameter adjustment mechanism for controlling the preset parameter values ​​of the eruption medium in the eruption medium storage mechanism (31); and, The preset parameter values ​​of the ejection medium include at least multiple sets of pressure values ​​and ejection durations of the ejection medium, with each set of pressure values ​​and ejection durations corresponding to one intermittent ejection. A gas valve (33) is provided between the ejection medium storage mechanism (31) and the ejection medium supply mechanism (32), and a control device is provided to regulate the output parameters of the ejection medium in the ejection medium storage mechanism (31) by controlling the gas valve (33).

2. The experimental apparatus for natural gas hydrate eruption according to claim 1, characterized in that, The sample preparation system (2) includes at least a vibration table (21) that contacts the eruption simulation box (1) and is capable of oscillating the eruption simulation box (1), and a leveling structure that is movably disposed in the receiving cavity (11) along the extending direction of the receiving cavity (11). The leveling structure is used to level the sample surface in the receiving cavity (11).

3. An experimental apparatus for natural gas hydrate eruption according to claim 1 or 2, characterized in that, The monitoring system (4) includes at least a high-speed camera (42) for capturing the eruption process in the eruption simulation chamber (1) and a pressure sensor (41) disposed on the inner wall of the eruption simulation chamber (1).

4. The experimental apparatus for natural gas hydrate eruption according to claim 3, characterized in that, The monitoring system (4) also includes a light source (43) for providing observation light to the eruption simulation chamber (1).

5. An experimental apparatus for natural gas hydrate eruption according to claim 1 or 2, characterized in that, The parameter adjustment mechanism includes at least one ejection duration control unit (34) disposed between the ejection simulation box (1) and the ejection medium storage mechanism (31), the ejection duration control unit (34) being used to control the ejection duration of the ejection medium introduced into the ejection simulation box (1) by the ejection medium storage mechanism (31).

6. The experimental apparatus for natural gas hydrate eruption according to claim 5, characterized in that, The eruption duration control unit (34) includes a solenoid valve connected between the eruption medium storage mechanism (31) and the eruption simulation box (1), a time relay electrically connected to the solenoid valve, and a signal triggering device electrically connected to the time relay. The time relay triggers the opening and closing of the solenoid valve according to the signal triggering device.

7. An experimental apparatus for natural gas hydrate eruption according to claim 6, characterized in that, The parameter adjustment mechanism further includes a temperature control unit for adjusting the temperature of the ejection medium in the ejection medium storage mechanism (31), and the temperature control unit is electrically connected to the signal triggering device.

8. An experimental apparatus for natural gas hydrate eruption according to claim 7, characterized in that, The temperature control unit includes a multi-level temperature control structure (35) arranged sequentially from the ejection medium supply mechanism (32) to the ejection medium storage mechanism (31), and the temperature of the multi-level temperature control structure (35) increases or decreases step by step.

9. An experimental apparatus for natural gas hydrate eruption according to claim 8, characterized in that, The ejection medium storage mechanism (31) is also provided with a pressure detection feedback unit, which is used to monitor the gas pressure in the ejection medium storage mechanism (31) and feed it back to the signal triggering device.

10. A method for simulating the eruption of natural gas hydrates, characterized in that, The experimental apparatus for natural gas hydrate eruption as described in any one of claims 1-9 is used, and the method for simulating natural gas hydrate eruption includes: S100. Construct a simulated eruption environment with preset simulation values ​​in the eruption simulation chamber; S200, Adjust the pressure of the ejection medium and the ejection duration to reach their respective preset parameter values; S300: Open the eruption medium supply mechanism until the eruption medium used for eruption reaches at least part of the preset parameter values, trigger the eruption medium to simulate eruption in the eruption simulation box, and monitor the eruption process through the monitoring system; S400: Collect monitoring data from the monitoring system; In step S300, the simulated eruption process includes multiple intermittent eruptions at intervals, and the preset parameter values ​​for each intermittent eruption are not exactly the same.

11. The method for simulating natural gas hydrate eruption according to claim 10, characterized in that, The construction method in step S100 specifically includes: S101. Mix silty clay with water until the moisture content is 15%-20% to obtain a soil sample; S102. Place the obtained soil sample in the eruption simulation chamber and vibrate to compact it until the void ratio of the soil sample is no greater than 0.

6. Then level the soil sample to obtain the soil sample layer. S103. Pour simulated seawater into the eruption simulation chamber until the liquid level is 3 / 5-4 / 5 of the chamber's height, thus creating a simulated eruption environment.

12. The method for simulating natural gas hydrate eruption according to claim 10, characterized in that, The preset parameter values ​​in step S200 include multiple sets of pressure values ​​and eruption durations of the eruption medium, with each set of pressure values ​​and eruption durations corresponding to one intermittent eruption.

13. The method for simulating the eruption of natural gas hydrates according to claim 12, characterized in that, The preset pressure values ​​of adjacent intermittent eruptions increase or decrease in a gradient manner.

14. The method for simulating natural gas hydrate eruption according to claim 13, characterized in that, The preset parameter values ​​in step S200 also include the temperature of the ejection medium.

15. The method for simulating natural gas hydrate eruption according to claim 14, characterized in that, In step S300, when the pressure and temperature of the ejection medium both reach the preset parameter range, the ejection medium is triggered to eject.

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