Gas hydrate reservoir microbial consolidation mining model test device and test method

Abstract

The application discloses a gas hydrate reservoir microbial reinforcement mining model test device and a test method. The gas hydrate reservoir microbial reinforcement mining model test device comprises a reaction kettle, an injection control system, a seawater supply system, a gas supply system, a microorganism supply system, a cementing fluid supply system, a sensor assembly and a hydrate mining system; the sensor assembly is used for acquiring the temperature, pressure, water content, hydrate saturation, deformation, strength and mineral component distribution of the hydrate reservoir in the reinforcement-decomposition process. The technical scheme of the application provides a test device which can observe the hydrate reservoir seepage field, temperature field, deformation field, hydrate and mineral content distribution evolution law in the process of the microbial reinforcement natural gas hydrate reservoir and mining in real time.

Description

Technical Field

[0001] This invention relates to the field of energy natural gas hydrate development technology, and in particular to a test device and test method for microbial reinforcement mining model of gas hydrate reservoirs. Background Technology

[0002] Natural gas hydrates are a highly efficient, clean, and abundant new energy source, and their development can greatly alleviate the scarcity and insufficiency of resources such as oil and natural gas. Hydrate-bearing sediments are composed of gas, a rock and soil framework, water, and solid hydrates through complex mechanisms, which become extremely complex during the phase transition process of hydrate decomposition. During hydrate extraction, the strength of the sediments decreases, making wellbores, wellheads, pipelines, and offshore platforms buried within the sediments prone to instability, and even leading to large-scale seafloor subsidence and submarine landslides. Currently, in domestic and international pilot production, the gas production rate of hydrates remains relatively low, failing to reach commercial extraction levels. To achieve safe and efficient extraction of hydrate deposits, it is essential to reinforce and modify hydrate-bearing reservoirs to improve their strength and stability.

[0003] In recent years, microbial induced calcium carbonate deposition (MICP) technology has been applied as a novel, green, and environmentally friendly technology in the field of geotechnical engineering for soft soil foundation reinforcement, slope treatment, and prevention of soil liquefaction. However, there are currently few experimental devices for evaluating the mechanical properties of natural gas hydrate reservoirs through microbial reinforcement. Furthermore, existing devices cannot monitor in real time the distribution and evolution of reservoir pressure field, temperature field, deformation field, hydrate saturation, mechanical strength, and mineral content during the microbial reinforcement and extraction of natural gas hydrate reservoirs.

[0004] Therefore, in order to better study the influence of microbial reinforcement mining process on the physical property parameters of hydrate reservoir models and its impact on the hydrate mining process, there is an urgent need to provide an experimental device that can observe in real time the evolution of seepage field, temperature field, deformation field, and hydrate and mineral content distribution in hydrate reservoirs during the microbial reinforcement process of natural gas hydrate reservoirs. Summary of the Invention

[0005] The main objective of this invention is to propose a model test device for the microbial reinforcement and exploitation of gas hydrate reservoirs. This device aims to provide a test device that can observe in real time the evolution of seepage field, temperature field, deformation field, and hydrate and mineral content distribution in hydrate reservoirs during the microbial reinforcement and exploitation process.

[0006] To achieve the above objectives, the present invention proposes a test device for microbial reinforcement and exploitation of gas hydrate reservoirs, comprising:

[0007] A reaction vessel, wherein a reaction chamber is formed inside the reaction vessel for placing test sand, and a well shaft is detachably installed inside the reaction chamber and communicates with the well shaft;

[0008] An injection control system, wherein the injection control system is connected to the reaction chamber;

[0009] A seawater supply system, wherein the outlet of the seawater supply system is connected to the reaction chamber through the injection control system to add artificial seawater into the reaction chamber;

[0010] A gas supply system, wherein the gas outlet of the gas supply system is connected to the reaction chamber through the injection control system to add methane or carbon dioxide gas into the reaction chamber;

[0011] A microbial supply system is provided, the outlet of which is connected to the reaction chamber via the injection control system to add bacterial solution into the reaction chamber;

[0012] A cementing solution supply system, wherein the outlet of the cementing solution supply system is connected to the reaction chamber through the injection control system to add cementing solution into the reaction chamber;

[0013] A hydrate extraction system, connected to the wellbore, is used to reduce the pressure inside the reaction chamber to promote the decomposition of hydrates within the reaction chamber.

[0014] A sensor assembly, located in the reaction vessel, is used to acquire the temperature, pressure, water content, hydrate saturation, deformation, strength, and mineral composition distribution of the hydrate reservoir during the consolidation-decomposition process.

[0015] In one embodiment of the present invention, the sensor assembly includes:

[0016] A pressure stabilizing system, wherein the pressure stabilizing system has a pressure sensor, which is located inside the reaction vessel and is used to measure the pressure inside the reaction chamber in real time;

[0017] A temperature control system, wherein the temperature control system has a temperature sensor, which is located inside the reaction vessel and is used to measure the temperature inside the reaction chamber in real time;

[0018] A shear wave velocity measurement system is used to monitor the sediment intensity of the hydrate reservoir within the reaction chamber in real time.

[0019] A time-domain reflectometry system is used to monitor the saturation of the hydrate reservoir in the reaction chamber in real time.

[0020] A displacement monitoring system is installed above the reactor to monitor the displacement changes of the hydrate reservoir in the reaction chamber in real time.

[0021] In one embodiment of the present invention, the time-domain reflectometry system has a plurality of time-domain reflectometry probes, which are spaced apart along the axial direction of the reactor.

[0022] In one embodiment of the present invention, the time-domain reflectometry probe includes a time-domain reflectometry transmitter and a time-domain reflectometry receiver. In the same time-domain reflectometry probe, the time-domain reflectometry transmitter and the time-domain reflectometry receiver are located on the same horizontal plane, and the line connecting the time-domain reflectometry transmitter and the time-domain reflectometry receiver does not pass through the axis of the reactor.

[0023] In one embodiment of the present invention, the shear wave velocity measurement system has multiple shear wave velocity probes, which are spaced apart along the axial direction of the reactor.

[0024] In one embodiment of the present invention, the shear wave velocity probe includes a shear wave transmitter and a shear wave receiver. In the same shear wave velocity probe, the shear wave transmitter and the shear wave receiver are located on the same horizontal plane, and the line connecting the shear wave transmitter and the shear wave receiver does not pass through the axis of the reactor.

[0025] In one embodiment of the present invention, multiple pressure sensors and / or multiple temperature sensors are provided, and the multiple pressure sensors and / or multiple temperature sensors are distributed at intervals along the axial direction of the reaction vessel.

[0026] In one embodiment of the present invention, the voltage stabilizing system further includes a temperature control device, which uses anhydrous ethanol as a circulating medium to regulate the temperature inside the reaction chamber.

[0027] In one embodiment of the present invention, the temperature control device includes:

[0028] The shell has an installation cavity formed inside it, the reactor is disposed in the installation cavity, and a circulating refrigeration space is formed between the outer surface of the reactor and the cavity wall of the installation cavity for inputting anhydrous ethanol. The shell is also provided with an inlet and an outlet that communicate with the circulating refrigeration space.

[0029] A thermostat, the thermostat being located outside the housing and having a temperature control chamber;

[0030] A liquid inlet pipe, the outlet and inlet of which are respectively connected to the liquid inlet and the temperature control chamber; and

[0031] The liquid outlet pipe has its inlet and outlet connected to the liquid outlet and the temperature control chamber, respectively.

[0032] This invention also proposes a test method based on the above-described microbial reinforcement and exploitation model test device for gas hydrate reservoirs, the test method comprising the following steps:

[0033] The test sand was packed into the reaction chamber, compacted and sealed, and artificial seawater was injected into the reaction chamber until it was saturated. The temperature and pressure inside the reactor were adjusted to the preset temperature and pressure.

[0034] Methane or carbon dioxide gas is added to the reaction chamber to obtain a hydrate reservoir;

[0035] Inject bacterial solution into the reaction chamber;

[0036] The cementing solution is injected into the reaction chamber in multiple stages to allow the bacterial solution in the reaction chamber to react with the cementing solution, thereby consolidating the hydrate reservoir.

[0037] The pressure inside the reactor is reduced by the hydrate extraction system, so as to decompose the hydrate reservoir inside the reactor.

[0038] To obtain the temperature, pressure, water content, hydrate saturation, deformation, strength, and mineral composition distribution of the hydrate reservoir during the reinforcement-decomposition process.

[0039] The experimental device for microbial reinforcement and exploitation model of gas hydrate reservoir of the present invention can first add test sand into the reaction chamber of the reactor, and then add artificial seawater and methane or carbon dioxide gas into the reaction chamber through the seawater supply system and the gas supply system, respectively, while adjusting the pressure and temperature to approximate the conditions of a marine reservoir to form an initial seabed hydrate reservoir model; then add bacterial solution and cementing solution into the reaction chamber through the microbial supply system and the cementing solution supply system, respectively, to reinforce the hydrate reservoir in the reaction chamber; and then use the hydrate exploitation system to depressurize and decompose the hydrate in the hydrate reservoir. During this process, sensor components (such as pressure sensors, temperature sensors, shear wave velocity measurement systems, time-domain reflectometry systems, displacement monitoring systems, etc.) can be used to obtain the temperature, pressure, water content, hydrate saturation, deformation, strength, and mineral composition distribution of the hydrate reservoir during the reinforcement-decomposition process. This allows for the acquisition and real-time observation of the seepage field, temperature field, deformation field, and the evolution of hydrate and mineral content distribution in the hydrate reservoir. Consequently, the mechanical mechanisms and production changes during hydrate reinforcement and mining can be studied, further preventing potential geological disasters and achieving safe and efficient hydrate mining. Attached Figure Description

[0040] To more clearly illustrate the technical solutions in the embodiments of the present invention or 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 only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0041] Figure 1 This is a schematic diagram of an embodiment of the microbial reinforcement mining model test device for gas hydrate reservoirs according to the present invention;

[0042] Figure 2 This is a partial structural schematic diagram of an embodiment of the gas hydrate reservoir microbial reinforcement mining model test device of the present invention;

[0043] Figure 3 for Figure 2 Sectional view at point AA;

[0044] Figure 4 This is a top view of the top end cap in one embodiment of the gas hydrate reservoir microbial reinforcement mining model test device of the present invention;

[0045] Figure 5 This is a flowchart of an embodiment of the test method of the experimental device for microbial reinforcement mining of gas hydrate reservoirs according to the present invention.

[0046] Explanation of icon numbers:

[0047]

[0048] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0049] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0050] It should be noted that if the embodiments of the present invention involve directional indicators (such as up, down, left, right, front, back, etc.), the directional indicators are only used to explain the relative positional relationship and movement of the components in a certain specific posture (as shown in the figure). If the specific posture changes, the directional indicators will also change accordingly.

[0051] Furthermore, if the embodiments of this invention involve descriptions such as "first" or "second," these descriptions are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of those features. Additionally, the technical solutions of the various embodiments can be combined with each other, but this must be based on the ability of those skilled in the art to implement them. If the combination of technical solutions is contradictory or impossible to implement, it should be considered that such a combination of technical solutions does not exist and is not within the scope of protection claimed by this invention.

[0052] This invention proposes a microbial reinforcement mining model test device 100 for gas hydrate reservoirs, aiming to provide a test device that can observe in real time the seepage field, temperature field, deformation field, and the evolution of hydrate and mineral content distribution in hydrate reservoirs during microbial reinforcement and mining processes.

[0053] The specific structure of the microbial reinforcement and exploitation model test device 100 for gas hydrate reservoirs of the present invention will be described below:

[0054] See also Figures 1 to 4 In one embodiment of the gas hydrate reservoir microbial reinforcement mining model test device 100 of the present invention, the gas hydrate reservoir microbial reinforcement mining model test device 100 includes a reaction vessel 10, an injection control system 20, a seawater supply system 30, a gas supply system 40, a microbial supply system 50, a cementing liquid supply system 60, a hydrate mining system 130, and a sensor assembly.

[0055] A reaction chamber is formed inside the reaction vessel 10, which is used to place test sand. A well shaft 14 is detachably installed inside the reaction chamber and is connected to the well shaft 14. An injection control system 20 is connected to the reaction chamber. The outlet of the seawater supply system 30 is connected to the reaction chamber through the injection control system 20 to add artificial seawater into the reaction chamber. The outlet of the gas supply system 40 is connected to the reaction chamber through the injection control system 20 to add methane or carbon dioxide gas into the reaction chamber. The outlet of the microbial supply system 50 is connected to the reaction chamber through the injection control system 20 to add bacterial solution into the reaction chamber. The outlet of the cementing liquid supply system 60 is connected to the reaction chamber through the injection control system 20 to add cementing liquid into the reaction chamber. A hydrate extraction system 130 is connected to the well shaft 14 to reduce the pressure in the reaction chamber to promote the decomposition of hydrates in the reaction chamber. A sensor assembly is installed in the reaction vessel 10 to acquire the temperature, pressure, water content, hydrate saturation, deformation, strength, and mineral composition distribution of the hydrate reservoir during the consolidation-decomposition process.

[0056] It is understood that the gas hydrate reservoir microbial reinforcement mining model test device 100 of the present invention can first add test sand into the reaction chamber of the reaction vessel 10, and add artificial seawater and methane or carbon dioxide gas into the reaction chamber through the seawater supply system 30 and the gas supply system 40 respectively, while adjusting the pressure and temperature to approximate the conditions of a marine reservoir to form an initial seabed hydrate reservoir model; then add bacterial solution and cementing solution into the reaction chamber through the microbial supply system 50 and the cementing solution supply system 60 respectively to reinforce the hydrate reservoir in the reaction chamber, and then use the hydrate mining system 130 to depressurize and decompose the hydrate in the hydrate reservoir. During this process, sensor components (such as pressure sensors, temperature sensors 81, shear wave velocity measurement systems 110, time-domain reflectometry systems 90, displacement monitoring systems 120, etc.) can be used to obtain the temperature, pressure, water content, hydrate saturation, deformation, strength, and mineral composition distribution of the hydrate reservoir during the reinforcement-decomposition process. This allows for the acquisition and real-time observation of the seepage field, temperature field, deformation field, and the evolution of hydrate and mineral content distribution in the hydrate reservoir. Consequently, the mechanical mechanisms and production changes during hydrate reinforcement and mining can be studied, further preventing potential geological disasters and achieving safe and efficient hydrate mining.

[0057] Specifically, the reactor 10 is used to fill test sand to provide a reaction environment; the seawater supply system 30 can be connected to the reaction chamber through the first booster pump 21 and the first liquid flow meter 22 in the injection control system 20, via the reserved opening 12a at the top of the reactor 10, to inject seawater into the reaction chamber; the gas supply system 40 can be connected to the reaction chamber through the second booster pump 23, the gas path stabilizer tank 24, the first gas flow meter 25, and the PID pressure controller 26 in the injection control system 20, via the reserved opening 12a at the bottom of the reactor 10, to add methane or carbon dioxide gas into the reaction chamber; the microbial supply system 50 can be connected to the reaction chamber through the third booster pump 27 and the second liquid flow meter 28 in the injection control system 20, via the reserved opening 12a at the top of the reactor 10, to add bacterial solution into the reaction chamber; the cementing liquid supply device can be connected to the reaction chamber through the fourth booster pump 29 and the third liquid flow meter 210 in the injection control system 20, via the reserved opening 12a at the bottom of the reactor 10. The system is connected to the reaction chamber to add a cementing liquid. The hydrate extraction system 130 may include a vacuum pump 131, a fume hood 132, a PID regulator 133, a gas-liquid separator 134, a measuring cylinder 135, and a second gas flow meter 136. In this way, the pressure in the reaction chamber can be controlled by the vacuum pump 131, fume hood 132, and PID regulator 133 to create a low-pressure environment in the reaction chamber for depressurization extraction of the hydrate reservoir in the reactor 10. The extracted material can be collected in the gas-liquid separator 134 for gas-liquid separation. The separated gas flows to the second gas flow meter 136 under the action of the fume hood 132 to calculate the gas flow rate. The liquid can flow into the measuring cylinder 135 below the gas-liquid separator 134 to read the liquid flow rate (or the liquid can be weighed using a balance to obtain the weight, and the liquid flow rate can be obtained by conversion). Finally, the proportion of each phase flow rate can be calculated.

[0058] A mining port 141 can be opened on the cylinder wall of the well shaft 14 so that the well shaft 14 is connected to the reaction chamber through the mining port 141. A screen is provided at the mining port 141 so that the fluid after decomposition and mining in the reaction vessel 10 can flow out through the mining port 141 and the sand and soil particles can be isolated in the reaction chamber through the screen.

[0059] Furthermore, in conjunction with reference Figure 1 and Figure 2In one embodiment, the sensor assembly includes a pressure stabilization system 70, a temperature control system 80, a shear wave velocity measurement system 110, a time-domain reflectometry system 90, and a displacement monitoring system 120. The pressure stabilization system 70 has a pressure sensor located inside the reactor 10 for real-time measurement of the pressure inside the reaction chamber. The temperature control system 80 has a temperature sensor 81 located inside the reactor 10 for real-time measurement of the temperature inside the reaction chamber. The shear wave velocity measurement system 110 is used to monitor the sediment intensity of the hydrate reservoir inside the reaction chamber in real-time. The time-domain reflectometry system 90 is used to monitor the saturation of the hydrate reservoir inside the reaction chamber in real-time. The displacement monitoring system 120 is located above the reactor 10 for real-time monitoring of the displacement changes of the hydrate reservoir inside the reaction chamber.

[0060] The displacement monitoring system 120 includes a displacement sensor, specifically a modified displacement sensor for measuring deformation of the top sediment. The modified displacement sensor has a circular, incompressible sheet fixed to the tip of the linear variable differential transformer (LVDT) to prevent the tip of the LVDT from being inserted into the hydrate reservoir and affecting the measurement accuracy.

[0061] Furthermore, the data acquisition system can collect and display data from various systems, including the injection control system 20, seawater supply system 30, air supply system 40, microbial supply system 50, cementing liquid supply system 60, pressure stabilization system 70, temperature control system 80, and shear wave velocity measurement system 110, so that experimental personnel can observe the changes in various data parameters in real time.

[0062] In this embodiment, during the experiment, the pressure in the reaction chamber can be adjusted by the pressure sensor in the pressure stabilization system 70, so that the pressure in the reaction chamber is adjusted to the preset pressure corresponding to the depth of the research sea area, so as to simulate the actual environment and further ensure the accuracy of monitoring.

[0063] Similarly, during the experiment, the temperature inside the reaction chamber can be adjusted by the temperature sensor 81 in the temperature control system 80, so that the temperature inside the reaction chamber is adjusted to the preset temperature corresponding to the depth of the research sea area, so as to simulate the actual environment and further ensure the accuracy of monitoring.

[0064] Furthermore, the displacement monitoring system 120 has a displacement sensor, which is installed on the top of the reactor 10 with the sensor port facing the reactor 10. The displacement sensor measures the deformation of the hydrate reservoir during the reinforcement and decomposition mining process to obtain more accurate changes in physical property parameters.

[0065] Because the pressure inside the reactor 10 is relatively high during the experiment, a vent valve can be installed on the reactor 10 to facilitate the smooth injection of artificial seawater into the reaction chamber. When artificial seawater needs to be injected, the vent valve is opened first to make the pressure inside the reaction chamber consistent with the atmospheric pressure, so that artificial seawater can be smoothly injected into the reaction chamber. In addition, the vent valve can also facilitate the depressurization of the reactor 10 after the experiment.

[0066] The specific preparation method for the bacterial suspension in microbial system 50 is as follows: Sporosarcina pasteurii was vacuum-dried and stored as a lyophilized powder in ampoules. First, a liquid culture medium was prepared, consisting of 20 g / L yeast extract, 10 g / L NH4Cl, 10 mg / L MnSO4·H2O, and 24 mg / L NiCl2·6H2O, adjusted to pH 9.0 with 1M NaOH. The liquid culture medium was sterilized by high-temperature steam at 121℃ for 30 min, then placed on a sterile operating table to cool. The upper part of the ampoule was heated with an alcohol lamp, and a few drops of water were added to break it. The inner tube was removed with forceps, and the cotton stopper was opened. 1 mL of liquid culture medium was pipetted into the inner tube to dissolve the lyophilized powder. The dissolved Sporosarcina pasteurii was then poured into a culture tube containing 6 mL of liquid culture medium and mixed thoroughly to obtain the bacterial suspension.

[0067] The specific preparation method of the cementing solution in the cementing solution supply system 60 is as follows: dissolve CaCl2 and urea in water to prepare a 0.5M CaCl2 and 0.75M urea mixture, and add 3 g / L of beef extract at the same time to obtain the cementing solution.

[0068] Furthermore, in conjunction with reference Figure 1 and Figure 2 In one embodiment of the microbial reinforcement and exploitation model test device 100 for gas hydrate reservoirs of the present invention, the time domain reflectance measurement system 90 has multiple time domain reflectance probes 92, which are spaced apart along the axial direction of the reaction vessel 10. Since the saturation of the hydrate reservoir at different depths will vary during the reinforcement and decomposition process, in order to reduce detection errors and improve accuracy, multiple time domain reflectance probes 92 are spaced apart in the reaction chamber. The hydrate saturation at different locations of the hydrate reservoir can be obtained through multiple time domain reflectance probes 92, and the changes in physical property parameters can be calculated to improve the accuracy of monitoring.

[0069] Specifically, the time-domain reflectometry system 90 also includes a time-domain reflectometry controller 91 to control the operation of the time-domain reflectometry probe 92.

[0070] Similarly, the shear wave velocity measurement system 110 has multiple shear wave velocity probes 112, which are spaced apart along the axial direction of the reactor 10. Since the sediment intensity of the hydrate reservoir varies at different depths during the reinforcement and decomposition process, in order to reduce detection errors and improve accuracy, multiple shear wave velocity probes 112 are spaced apart in the reaction chamber. The sediment intensity of the hydrate reservoir at different locations can be obtained through multiple shear wave velocity probes 112, and the changes in physical property parameters can be calculated to improve the accuracy of monitoring.

[0071] Specifically, the time-domain reflectometry system 90 also includes a shear wave velocity controller 111 to control the operation of the shear wave velocity probe 112.

[0072] Similarly, multiple pressure sensors and / or temperature sensors 81 are provided, and the multiple pressure sensors and / or multiple temperature sensors 81 are distributed at intervals along the axial direction of the reactor 10. Since the pressure, temperature and other parameters of the hydrate reservoir will vary at different depths during the reinforcement and decomposition process, in order to reduce detection errors and improve accuracy, multiple pressure sensors and multiple temperature sensors 81 can be used to obtain the changes in pressure, temperature and other parameters of the hydrate reservoir at different locations. By calculation, a more accurate change in physical property parameters can be obtained, thereby improving the accuracy of monitoring.

[0073] See also Figure 1 and Figure 2 In one embodiment of the microbial reinforcement mining model test device 100 for gas hydrate reservoirs of the present invention, the time-domain reflectometry probe 92 includes a time-domain reflectometry transmitter 921 and a time-domain reflectometry receiver 922. Within the same time-domain reflectometry probe 92, the time-domain reflectometry transmitter 921 and the time-domain reflectometry receiver 922 are located on the same horizontal plane, and the line connecting the time-domain reflectometry transmitter 921 and the time-domain reflectometry receiver 922 does not pass through the axis of the reaction vessel 10. Thus, under the action of the time-domain reflectometry transmitter 921 and the time-domain reflectometry receiver 922, data can be obtained and... The real-time observation of hydrate saturation at corresponding locations in the hydrate reservoir follows existing technology and will not be elaborated here. Furthermore, since the wellbore 14 is positioned at the axial center of the reactor 10 and is coaxial with the reactor 10, by ensuring that the connection between the time-domain reflectometry transmitter 921 and the time-domain reflectometry receiver 922 does not pass through the axis of the reactor 10, the wellbore 14 can be prevented from interfering with the normal operation of the time-domain reflectometry probe 92, allowing the time-domain reflectometry receiver 922 to receive the signal emitted by the time-domain reflectometry transmitter 921.

[0074] Similarly, the shear wave velocity probe 112 includes a shear wave transmitter 1121 and a shear wave receiver 1122. In the same shear wave velocity probe 112, the shear wave transmitter 1121 and the shear wave receiver 1122 are located on the same horizontal plane. In this way, the sediment intensity of the hydrate reservoir at the corresponding location can be obtained and observed in real time under the action of the shear wave transmitter 1121 and the shear wave receiver 1122. The specific working principle is existing technology and will not be described in detail here. In addition, since the wellbore 14 is set at the axial position of the reactor 10 and the wellbore 14 is coaxial with the reactor 10, by making the connection between the shear wave transmitter 1121 and the shear wave receiver 1122 not pass through the axis of the reactor 10, the wellbore 14 can be prevented from affecting the normal operation of the shear wave velocity probe 112, so that the shear wave receiver 1122 can receive the signal emitted by the shear wave transmitter 1121.

[0075] Furthermore, in conjunction with reference Figure 2 In one embodiment of the gas hydrate reservoir microbial reinforcement mining model test device 100 of the present invention, in the same time domain reflectance probe 92, the line connecting the time domain reflectance transmitter 921 and the axis of the reactor 10 is defined as the first line, and the line connecting the time domain reflectance receiver 922 and the axis of the reactor 10 is defined as the second line. The angle between the first line and the second line is α, which satisfies the condition: 0° < α < 170°. Since the wellbore 14 has a certain size, by controlling the angle between the first line and the second line between 0° and 170°, the wellbore 14 can be effectively prevented from affecting the normal operation of the time domain reflectance probe 92, so that the time domain reflectance receiver 922 can receive the signal emitted by the time domain reflectance transmitter 921.

[0076] Furthermore, to ensure the accuracy of the detection, the distance between the time-domain reflectometry receiver 922 and the time-domain reflectometry transmitter 921 can be greater than 2 cm.

[0077] Similarly, in the same shear wave velocity probe 112, the line connecting the shear wave transmitter 1121 and the axis of the reactor 10 is defined as the third line, and the line connecting the shear wave receiver 1122 and the axis of the reactor 10 is defined as the fourth line. The angle between the third line and the fourth line is β, which satisfies the condition: 0° < β < 170°. Since the well shaft 14 has a certain size, by controlling the angle between the third line and the fourth line between 0° and 170°, the well shaft 14 can be kept away from affecting the normal operation of the shear wave velocity probe 112, so that the shear wave receiver 1122 can receive the signal emitted by the shear wave transmitter 1121.

[0078] Furthermore, in order to ensure the accuracy of the detection, the distance between the shear wave receiver 1122 and the shear wave transmitter 1121 can be greater than 2cm.

[0079] Furthermore, in conjunction with reference Figure 1 In one embodiment of the gas hydrate reservoir microbial reinforcement mining model test device 100 of the present invention, the side wall of the reaction vessel 10 is provided with a plurality of spaced installation ports, which are respectively used to install a time domain reflector transmitter 921, a time domain reflector receiver 922, a shear wave transmitter 1121 and a shear wave receiver 1122.

[0080] With this configuration, during the assembly process, the time domain reflector 921, the time domain reflector 922, the shear wave emitter 1121, and the shear wave receiver 1122 can be installed at multiple mounting ports on the side wall of the reactor 10.

[0081] Of course, the pressure sensor and temperature sensor 81 can be installed at the corresponding mounting ports on the side wall of the reactor 10.

[0082] Furthermore, in conjunction with reference Figure 4 In one embodiment of the gas hydrate reservoir microbial reinforcement mining model test device 100 of the present invention, the top and bottom of the reactor 10 are provided with a plurality of spaced openings 12a, and the injection control system 20 is connected to the reactor 10 through the openings 12a.

[0083] With this configuration, the injection control system 20 can be connected to the outlet of the injection control system 20, the outlet of the gas supply system 40, the outlet of the microbial supply system 50, the outlet of the cementing liquid supply system 60, etc., respectively, through the opening 12a on the top or bottom of the reactor 10; and an opening 12a is provided at the center of the top of the reactor 10, which is a wellbore external interface 12b, so that the top of the wellbore 14 passes through the wellbore external interface 12b to connect with the hydrate extraction system 130.

[0084] Specifically, the reactor 10 can be roughly cylindrical in shape, including a reactor body 11, a top end cover 1312 covering the top of the reactor body 11, and a bottom end cover covering the bottom of the reactor body 11. The top end cover 1312 and the bottom end cover can be locked to the reactor body 11 by bolts. Furthermore, the top end cover 1312 and the bottom end cover are provided with multiple spaced openings 12a.

[0085] See also Figure 1 In one embodiment of the microbial reinforcement mining model test device 100 for gas hydrate reservoirs of the present invention, the temperature control system 80 further includes a temperature control device 82, which uses anhydrous ethanol as a circulating medium to regulate the temperature inside the reaction chamber. With this configuration, during the experiment, the temperature inside the reaction chamber can be regulated by the temperature control device 82 to achieve a temperature corresponding to the depth of the research sea area, thereby simulating the actual environment and further ensuring the accuracy of monitoring.

[0086] Furthermore, in conjunction with reference Figure 1 In one embodiment of the microbial reinforcement mining model test device 100 for gas hydrate reservoirs of the present invention, the constant temperature device 82 includes a shell 821, a temperature controller 822, an inlet pipe, and an outlet pipe; an installation cavity is formed inside the shell 821, the reaction vessel 10 is disposed in the installation cavity, and a circulating cooling space is formed between the outer surface of the reaction vessel 10 and the cavity wall of the installation cavity for inputting anhydrous ethanol; the shell 821 is also provided with an inlet and an outlet communicating with the circulating cooling space; the temperature controller 822 is disposed outside the shell 821 and has a temperature control chamber; the outlet and inlet of the inlet pipe are respectively connected to the inlet and the temperature control chamber; the inlet and outlet of the outlet pipe are respectively connected to the outlet and the temperature control chamber.

[0087] With this setup, the temperature of anhydrous ethanol in the temperature control chamber is first controlled by the temperature controller 822. Once the temperature of the anhydrous ethanol in the temperature control chamber is adjusted to the required temperature, the anhydrous ethanol is transported to the circulating cooling space through the liquid inlet pipe. The anhydrous ethanol in the circulating cooling space is used to regulate the temperature of the reactor 10. Then, the anhydrous ethanol in the circulating space flows back to the temperature control chamber through the liquid outlet pipe. In this way, a circulation channel is formed between the temperature control chamber, the liquid inlet pipe, the circulating cooling space, and the liquid outlet pipe to regulate the temperature of the reactor 10. This allows the temperature in the reaction chamber to be adjusted to the temperature corresponding to the depth of the research sea area, so as to simulate the actual environment.

[0088] Furthermore, the shell 821 is an explosion-proof vessel. Since the actual research sea area has a high pressure, the pressure inside the reactor 10 also needs to be set high during the experiment. Thus, by placing the reactor 10 in the installation cavity of the explosion-proof vessel, the personal safety of the experimenter can be protected, and the reactor 10 can be prevented from exploding during the experiment, thus injuring the experimenter.

[0089] Of course, in other embodiments, a cooling plate can also be directly installed inside the reactor 10 to regulate the temperature inside the reactor 10.

[0090] See also Figure 5 The present invention also proposes a test method for a microbial reinforcement mining model test device 100 for gas hydrate reservoirs, the test method comprising the following steps:

[0091] S10, the test sand is loaded into the reaction chamber, compacted and sealed, artificial seawater is injected into the reaction chamber until saturation, and the temperature and pressure in the reaction vessel 10 are adjusted to the preset temperature and pressure (temperature and pressure corresponding to the depth of the sea area under study).

[0092] Specifically, the experimenter first fills the reaction chamber with the mixed test sand, then turns on the first booster pump 21 corresponding to the seawater supply system 30 to add artificial seawater into the reaction chamber. At the same time, the first liquid flow meter 22 calculates the amount of artificial seawater added. When the amount added reaches the preset value, the corresponding first booster pump 21 is turned off to stop adding artificial seawater into the reaction chamber. Then, the temperature and pressure in the reactor 10 are adjusted to the preset temperature and pressure (temperature and pressure corresponding to the depth of the research sea area) by the temperature control system 80 and the pressure stabilization system 70, and then maintained for 24 hours to ensure that the disturbance effect of pressure and temperature on the experimental soil material is completely eliminated. At this time, the initial physical property parameters of the soil material are detected by multi-functional sensors (such as pressure sensor, temperature sensor 81, shear wave velocity measurement system 110, time domain reflection measurement system 90, displacement monitoring system 120, etc.).

[0093] S20, adding methane or carbon dioxide gas into the reaction chamber to obtain a hydrate reservoir;

[0094] Specifically, the second booster pump 23 corresponding to the gas supply system 40 is turned on to add methane or carbon dioxide gas into the reaction chamber. Then, the temperature and pressure are kept constant and stable for 72 hours to ensure the formation of the hydrate reservoir. The saturation of the generated hydrate reservoir is detected by the time domain reflectance measurement system 90.

[0095] S30, inject bacterial solution into the reaction chamber;

[0096] Specifically, turn on the third booster pump 27 corresponding to the microbial system 50 to add the bacterial solution into the reaction chamber through the corresponding third booster pump 27, and let it stand for 12 hours;

[0097] S40, inject cementing liquid into the reaction chamber in multiple stages to allow the bacterial solution in the reaction chamber to react with the cementing liquid, thereby consolidating the hydrate reservoir;

[0098] Specifically, the fourth booster pump 29 corresponding to the cementing liquid supply system 60 is turned on so that the cementing liquid is added into the reaction chamber for the first time through the corresponding fourth booster pump 29, and then cementing liquid is added once every 24 hours.

[0099] S50, the pressure inside the reactor 10 is reduced by the hydrate extraction system 130 so as to decompose the hydrate reservoir inside the reactor 10;

[0100] Specifically, the vacuum pump 131 in the hydrate extraction system 130 is turned on to create a low-pressure environment in the reaction chamber. Based on the set pressure reduction amplitude and rate, the hydrate reservoir in the reaction chamber is induced to decompose hydrates. The gas and liquid are then collected by the gas-liquid separator 134 in the hydrate extraction system 130, and the production rate is recorded.

[0101] S60, obtain the temperature, pressure, water content, hydrate saturation, deformation, strength, and mineral composition distribution of the hydrate reservoir during the reinforcement-decomposition process.

[0102] Specifically, sensor components (such as pressure sensors, temperature sensors 81, shear wave velocity measurement systems 110, time-domain reflectometry systems 90, displacement monitoring systems 120, etc.) are used to acquire the temperature, pressure, water content, hydrate saturation, deformation, strength, and mineral composition distribution of the hydrate reservoir during the reinforcement-decomposition process. This allows for the acquisition and real-time observation of the seepage field, temperature field, deformation field, and the evolution of hydrate and mineral content distribution in the hydrate reservoir. Consequently, the mechanical mechanisms and production changes during hydrate reinforcement and mining can be studied, further preventing potential geological disasters and achieving safe and efficient hydrate mining.

[0103] The above description is merely a preferred embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural transformations made using the contents of the present invention's specification and drawings under the inventive concept of the present invention, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A gas hydrate reservoir microbial consolidation production model test device, characterized in that, The application relates to a hydrate reservoir test device, which comprises the following parts: a reactor, which is internally formed with a reaction cavity for placing test sand, and is internally detachably installed with a well shaft, and is communicated with the well shaft; an injection control system, which is communicated with the reaction cavity; a seawater supply system, which is communicated with the reaction cavity through the injection control system, and is used for adding artificial seawater into the reaction cavity; a gas supply system, which is communicated with the reaction cavity through the injection control system, and is used for adding methane or carbon dioxide gas into the reaction cavity; a microorganism supply system, which is communicated with the reaction cavity through the injection control system, and is used for adding bacteria liquid into the reaction cavity; a cementing liquid supply system, which is communicated with the reaction cavity through the injection control system, and is used for adding cementing liquid into the reaction cavity; a hydrate exploitation system, which is connected with the well shaft, and is used for reducing the pressure in the reaction cavity, so as to promote the decomposition of a hydrate reservoir in the reaction cavity; a sensor assembly, which is arranged on the reactor, and is used for acquiring the temperature, pressure, water content, hydrate saturation, deformation, strength and mineral component distribution of the hydrate reservoir in the process of reinforcement and decomposition; the sensor assembly comprises the following parts: a pressure stabilizing system, which is internally provided with a pressure sensor, and is used for measuring the pressure in the reaction cavity in real time; a temperature control system, which is internally provided with a temperature sensor, and is used for measuring the temperature in the reaction cavity in real time; a shear wave velocity measuring system, which is used for monitoring the sediment strength of the hydrate reservoir in the reaction cavity in real time; a time domain reflectometry system, which is used for monitoring the saturation of the hydrate reservoir in the reaction cavity in real time; a displacement monitoring system, which is arranged above the reactor, and is used for monitoring the displacement change of the hydrate reservoir in the reaction cavity in real time; the time domain reflectometry system is internally provided with a plurality of time domain reflectometry probes, which are axially and spacedly arranged on the reactor; the time domain reflectometry probe comprises a time domain reflectometry transmitter and a time domain reflectometry receiver, the time domain reflectometry transmitter and the time domain reflectometry receiver are arranged on the same horizontal plane in the same time domain reflectometry probe, and the line between the time domain reflectometry transmitter and the time domain reflectometry receiver does not pass through the shaft center of the reactor; the shear wave velocity measuring system is internally provided with a plurality of shear wave velocity probes, which are axially and spacedly arranged on the reactor.

2. The gas hydrate reservoir microbial consolidation production model test device according to claim 1, wherein, the shear wave velocity probe comprises a shear wave transmitter and a shear wave receiver, the shear wave transmitter and the shear wave receiver are arranged on the same horizontal plane in the same shear wave velocity probe, and the line between the shear wave transmitter and the shear wave receiver does not pass through the shaft center of the reactor.

3. The gas hydrate reservoir microbial consolidation production model test device according to claim 1, wherein, The pressure sensor and / or the temperature sensor are provided in plurality, and the plurality of pressure sensors and / or the plurality of temperature sensors are spaced along the axial direction of the reactor.

4. The gas hydrate reservoir microbial consolidation production model test device according to claim 1, wherein, The pressure stabilizing system further comprises a thermostat device, which uses anhydrous ethanol as circulating medium to regulate the temperature in the reaction cavity.

5. The gas hydrate reservoir microbial consolidation production model test device according to claim 4, wherein, The thermostat device comprises: a housing, which is provided with a mounting cavity, the reactor is arranged in the mounting cavity, and a circulating refrigeration space is formed between the outer surface of the reactor and the cavity wall of the mounting cavity for inputting anhydrous ethanol, the housing is further provided with a liquid inlet and a liquid outlet which communicate with the circulating refrigeration space; a temperature controller, which is arranged outside the housing and has a temperature control chamber; a liquid inlet pipe, the outlet and the inlet of which communicate with the liquid inlet and the temperature control chamber respectively; and a liquid outlet pipe, the inlet and the outlet of which communicate with the liquid outlet and the temperature control chamber respectively.

6. A test method based on the gas hydrate reservoir microbial reinforcement mining model test device according to any one of claims 1 to 5, characterized in that, The test method comprises the following steps: The test sand is loaded into the reaction cavity, compacted and sealed, artificial seawater is injected into the reaction cavity until saturation, and the temperature and pressure in the reactor are adjusted to the preset temperature and pressure; Methane or carbon dioxide gas is added to the reaction cavity to obtain a hydrate reservoir; Bacterial solution is injected into the reaction cavity; The bacterial solution in the reaction cavity is reacted with the cementing solution in multiple times to reinforce the hydrate reservoir; The pressure in the reactor is reduced by the hydrate exploitation system to decompose the hydrate reservoir in the reactor; The temperature, pressure, water content, hydrate saturation, deformation, strength and mineral composition distribution of the hydrate reservoir during the reinforcement and decomposition process are obtained.

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