CN113622875B - Natural gas hydrate solid-state fluidization mining cavity flow field simulation device and experimental method - Google Patents

Abstract

The invention discloses a natural gas hydrate solid fluidization mining cavity flow field simulation device and an experimental method. The natural gas hydrate solid fluidization mining cavity flow field simulation device includes a flow field simulation device, and the flow field simulation device includes a sealed box, a simulation tube, The jet tube and the recovery tube, the first end of the jet tube and the first end of the recovery tube are respectively inserted into the inside of the sealed box, the first end of the jet tube is provided with a jet hole, and the first end of the recovery tube is provided with a recovery hole, The jet tube is used to guide the jet fluid into the sealed box, and the recovery tube is used to guide the mixed fluid to leave the sealed box. The simulation tube is installed in the sealed box, and the jet hole and the recovery hole are located in the simulated tube. The invention simulates the scene when the jet in the excavation cavity is broken by sealing the box, and uses a simulation tube to simulate the inner wall of the excavation cavity, thereby simulating the influence of the flow field on the inner wall of the excavation cavity when the jet is broken. The invention relates to the technical field of a natural gas hydrate solid fluidization simulation device.

Description

Gas hydrate solid fluidization mining cavity flow field simulation device and experimental method

technical field

The invention relates to a natural gas hydrate solid fluidization mining cavity flow field simulation device and an experimental method in the technical field of natural gas hydrate solid fluidization simulation devices.

Background technique

Gas hydrate, also known as combustible ice, is an ice-like crystalline substance formed by natural gas and water under high pressure and low temperature conditions, and is distributed in deep sea or land permafrost. Because only a small amount of carbon dioxide and water are generated after its combustion, the pollution is far less than that of coal, oil, etc., and its reserves are huge, so it is a clean energy with great development prospects. Among the production methods of natural gas hydrates, the solid-state fluidized production method is one of the most likely methods to achieve commercial production of hydrates, which uses high-pressure submerged water jet technology to perform in-situ jet crushing operations on hydrate-containing sediment layers , the process of partially fluidizing the hydrate-containing sediment layer and then collecting it with a suction device to realize gas hydrate extraction.

Before mining, the mining drill bit first drills into the hydrate-containing sediment layer to form a borehole, and the jet device is opened in the borehole to break the hydrate layer jet and form a mining cavity. The hydrate is broken by the high-pressure jet and then recovered by the recovery device. It is absorbed and transported to the mining ship to complete the mining work. However, the structure of the mining cavity will also change with the mining work. According to the existing research, the distribution of the flow field in the mining cavity has an important impact on the recovery rate of the hydrate-bearing sediments and the stability of the borehole wall, especially It is the influence of multi-nozzle combined jet flow field on the internal environment of the mining cavity that needs further study. At present, most of the existing solid-state fluidization simulation devices only simulate jet crushing and hydrate collection, and seldom simulate and analyze the flow field inside the mining cavity. meet the need for further research.

Contents of the invention

The purpose of the present invention is to solve at least one of the technical problems existing in the prior art, and to provide a gas hydrate solid fluidization mining cavity flow field simulation device and experimental method, which can simulate the flow field distribution under actual jet mining conditions.

According to the embodiment of the first aspect of the present invention, there is provided a flow field simulation device for natural gas hydrate solid fluidization mining cavity, including a flow field simulation device, and the flow field simulation device includes a sealed box, a simulation tube, a jet tube and a recovery tube , the first end of the jet tube and the first end of the recovery tube are respectively inserted into the inside of the sealed box, the first end of the jet tube is provided with a jet hole, the first end of the recovery tube There is a recovery hole, the jet tube is used to guide the jet fluid into the sealed box, the recovery tube is used to guide the mixed fluid to leave the sealed box, the simulation tube is installed in the sealed box, and the jet Both the hole and the recovery hole are located in the simulated tube.

According to the embodiment of the first aspect of the present invention, further, the natural gas hydrate solid fluidization mining cavity flow field simulation device further includes a mixing device, a booster pump and a self-priming pump, and the mixing device is used to mix the solid phase The particles are mixed with the liquid phase, the two ends of the booster pump are respectively connected to the mixing device and the second end of the jet pipe, and the two ends of the self-priming pump are respectively connected to the second end of the recovery pipe. end and the mixing device.

According to the embodiment of the first aspect of the present invention, further, the sealed box includes a sealed box body and an end cover, the end cover is detachably connected to one end of the sealed box body, and the simulated tube can be removed from the Take it out of the sealed box.

According to the embodiment of the first aspect of the present invention, further, the numbers of the jet holes and the recovery holes are both more than two.

According to the embodiment of the first aspect of the present invention, further, the simulation tube is provided with a first pressure detection device.

According to the embodiment of the first aspect of the present invention, further, a weight sensor is provided at the bottom of the sealed box.

According to the embodiment of the first aspect of the present invention, further, the inner space of the simulated tube communicates with the inner space of the sealed box, and the sealed box is provided with an overflow valve.

According to the embodiment of the first aspect of the present invention, further, the sealed box is provided with a second pressure detection device.

According to the embodiment of the first aspect of the present invention, further, the sealed box and the simulated tube are both made of transparent materials.

According to the embodiment of the second aspect of the present invention, an experimental method based on any of the above gas hydrate solid fluidization mining cavity flow field simulation devices is provided, including:

S1. Making the simulated tube, determining the positions of the jet hole and the recovery hole in the sealed box, and the arrangement, geometry and quantity of the jet hole and the recovery hole;

S2. Installing a first pressure detection device on the inner wall of the simulated tube;

S3. Install the simulation tube, the jet tube and the recovery tube into the sealed box, close the end face of the sealed box, fill the inner space of the sealed box with water, and check all The tightness of the sealed box;

S4. Open the mixing device to obtain a solid-liquid phase mixture;

S5. Turn on the booster pump and the self-priming pump, form a flow field in the sealed box, and record the experimental data;

S6. According to the real-time weight value of the weight sensor, the rate of change of the weight of the sealed box with time is obtained, thereby calculating the deposition rate of solid phase particles in the sealed box, and then adjusting the mixing of the mixing device ratio and output power of said booster pump;

S7. Change the surface roughness, geometric shape, and geometric dimensions of the simulated tube, the mixing ratio of the mixing device, the output power of the booster pump, the positions and quantities of the jet holes and the recovery holes, At least one of the size and the overflow threshold value of the overflow valve, repeat the above S1 to S6.

The beneficial effects of the present invention are: the present invention simulates the scene when the jet in the excavation cavity is broken by sealing the box, and uses the simulation tube to simulate the inner wall of the excavation cavity, thereby simulating the influence of the flow field on the inner wall of the excavation cavity when the jet is broken.

Description of drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following will briefly describe the drawings that need to be used in the description of the embodiments. Apparently, the described drawings are only some embodiments of the present invention, not all embodiments, and those skilled in the art can obtain other designs and drawings based on these drawings without creative work.

Fig. 1 is the front view of the embodiment of the first aspect of the present invention;

Figure 2 is a cross-sectional view of an embodiment of the first aspect of the invention.

Detailed ways

This part will describe the specific embodiment of the present invention in detail, and the preferred embodiment of the present invention is shown in the accompanying drawings. Each technical feature and overall technical solution of the invention, but it should not be understood as a limitation on the protection scope of the present invention.

In the description of the present invention, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc. indicated orientations or positional relationships are based on the orientations or positional relationships shown in the drawings, and are only In order to facilitate the description of the present invention and simplify the description, it does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present invention.

In the description of the present invention, several means one or more, and multiple means more than two. Greater than, less than, exceeding, etc. are understood as not including the original number, and above, below, within, etc. are understood as including the original number. If the description of the first and second is only for the purpose of distinguishing the technical features, it cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features relation.

In the description of the present invention, unless otherwise clearly defined, words such as setting, installation, and connection should be understood in a broad sense, and those skilled in the art can reasonably determine the specific meanings of the above words in the present invention in combination with the specific content of the technical solution.

Referring to Figures 1 to 2, the gas hydrate solid fluidization mining cavity flow field simulation device in the embodiment of the first aspect of the present invention includes a flow field simulation device, and the flow field simulation device includes a sealed box 11, a simulation pipe 12, The jet tube 13 and the recovery tube 14, the first end of the jet tube 13 and the first end of the recovery tube 14 are respectively inserted into the inside of the sealed box 11 to realize the communication between the jet tube 13, the sealed box 11 and the recovery tube 14. The first end of the jet pipe 13 is provided with a jet hole 131 for simulating the jet crushing of natural gas hydrate; the first end of the recovery pipe 14 is provided with a recovery hole 141 for simulating the recovery of natural gas hydrate. The jet tube 13 is used to guide the jet fluid into the sealed box 11 , and the recovery tube 14 is used to guide the mixed fluid to leave the sealed box 11 . The inner wall of the simulated tube 12 is used to simulate the inner wall of the mining cavity. The simulated tube 12 is installed in the sealed box 11, and the jet hole 131 and the recovery hole 141 are located in the simulated tube 12. Specifically, the simulated tube 12 can be designed into various geometries The shape is used to simulate the excavation cavity with different structures, which increases the versatility of the simulation device.

In some embodiments, the experimenter can first fix the solid-phase sample on the inner wall of the simulation tube 12, and input the high-pressure jet into the jet tube 13, and the high-pressure jet is ejected from the jet hole 131 to achieve the crushing of the solid-phase sample , so as to simulate the actual jet crushing condition; record the influence of the flow field on the inner wall of the simulated pipe 12, and then simulate the influence of the flow field on the inner wall of the mining cavity.

In this embodiment, the gas hydrate solid fluidization excavation cavity flow field simulation device also includes a mixing device, a booster pump and a self-priming pump. The mixing device is used to mix the solid phase particles with the liquid phase to simulate jet breakage The resulting solid-liquid mixture. The input end of the booster pump is connected to the mixing device, and the output end is connected to the second end of the jet tube 13 for outputting the solid-liquid mixture to the flow field simulation device. The input end of the self-priming pump is connected to the second end of the recovery pipe 14, and the output end is connected to the mixing device for outputting the solid-liquid mixture to the mixing device to realize recycling of the solid-liquid mixture. Compared with the simulation method of jet crushing the solid phase sample in the sealed box 11, this method can avoid the disturbance of the flow field by the large solid phase sample, and with the change of the volume of the solid phase sample, its impact on the flow field The degree of disturbance will also change, resulting in uncontrollable experimental results. Therefore, the method of mixing the solid-liquid phase first and then inputting it into the flow field simulation device is adopted.

Specifically, the mixing device includes a feeder and a mixing tank. The solid particles are stored in the feeder. When the concentration of solid particles needs to be increased, the feeder adds solid particles to the mixing tank to increase the concentration of solid particles. The mixing tank is connected with the booster pump, and after the mixing tank completes the mixing, the mixture can be transported to the flow field simulation device through the booster pump.

Further, the sealed box 11 includes a sealed box body 111 and an end cover 112, and the end cover 112 is detachably connected to one end of the sealed box body 111. Optionally, the number of the end covers 112 is two, and the two end covers 112 are respectively provided in one-to-one correspondence with the two ends of the sealed box body 111 . After the end cover 112 is opened, the simulation tube 12 can be taken out from the sealed box 11, so that the simulation tube 12 can be replaced conveniently.

Furthermore, the number of the jet holes 131 and the recovery holes 141 are both more than two, so that the flow field situation of multi-nozzle combined jet breakage can be simulated.

Further, the simulation tube 12 is provided with a first pressure detection device for detecting the influence of the flow field. Preferably, there are multiple first pressure detection devices, all of which are distributed on the inner wall of the simulation tube 12, so that a more comprehensive and accurate simulation of the flow field can be performed.

Further, a weight sensor is provided at the bottom of the sealed box 11, which is used to detect the deposition amount of the solid phase particles in the sealed box 11, thereby calculating the deposition rate of the solid phase particles in the sealed box 11, thereby adjusting the mixing rate. The mixing ratio of the solid-liquid phase in the feeding device and the output power of the booster pump keep the concentration of solid-phase particles in the sealed box 11 within a certain range, preventing the experimental results from changing due to changes in the concentration of solid-phase particles. Optionally, the weight sensor can be electrically connected with the mixing device, the booster pump and the self-priming pump to realize the automatic adjustment of the solid phase particle concentration in the sealed box 11 .

Further, the inner space of the simulated pipe 12 communicates with the inner space of the sealed box 11, and the sealed box 11 is provided with an overflow valve to prevent the water pressure in the sealed box 11 from being too high, and it can also be used to simulate the occurrence of the excavation cavity. The impact of well wall leakage on the multiphase flow field and solid phase collection in the mining cavity, the number of overflow valves can be increased or decreased accordingly as needed.

Further, the sealed box 11 is provided with a second pressure detection device, the number of the second pressure detection device can be increased or decreased according to the needs, and the second pressure detection device is distributed on the inner surface of the sealed box 11 for detecting the opening of the overflow valve The influence of time overflow on the flow field can better simulate the situation when the well wall leaks in the mining cavity.

Furthermore, both the sealed box 11 and the simulation tube 12 are made of transparent materials, which is convenient for experimenters or visible light detection instruments to observe and detect the experiment process.

Based on the gas hydrate solid fluidization mining cavity flow field simulation device described in any of the above, the experimental method in the embodiment of the second aspect of the present invention includes:

S1. Make the simulated pipe 12 so that the roughness, geometric shape, and geometric dimensions of the inner wall of the simulated pipe 12 are close to the form of the excavation cavity to be simulated, so as to improve the simulation accuracy. Determine the position of the jet hole 131 and the recovery hole 141 in the sealed box 11, as well as the arrangement, geometry and quantity of the jet hole 131 and the recovery hole 141, so as to simulate the jet breaking form of the corresponding mining equipment;

S2. Installing a first pressure detection device on the inner wall of the simulation tube 12;

S3. Install the simulation tube 12, the jet tube 13 and the recovery tube 14 to the sealed box 11, seal the end face of the sealed box 11, fill the inner space of the sealed box 11 with water, and check the tightness of the sealed box 11 , to prevent flow field disturbance caused by leakage during the experiment;

S4. Turn on the mixing device to obtain a solid-liquid phase mixture;

S5. Turn on the booster pump and the self-priming pump, so that a flow field is formed in the sealed box 11, and record the experimental data of the first pressure detection device;

S6. According to the real-time weight value of the weight sensor, the rate of change of the weight of the sealed box 11 with time is obtained, thereby calculating the deposition rate of solid phase particles in the sealed box 11, and then adjusting the mixing ratio of the mixing device and the booster pump output power, the concentration of solid phase particles in the sealed box 11 is kept within a set range;

S7. Change the internal surface roughness, geometric shape, geometric size, mixing ratio of the mixing device, the output power of the booster pump, the position, quantity, size, and position of the jet hole 131 and the recovery hole 141 of the simulated pipe 12, and the size of the overflow valve. For at least one of the overflow thresholds, repeat the above S1 to S6.

The above is a specific description of the preferred embodiments of the present invention, but the invention is not limited to the described embodiments, those skilled in the art can also make various equivalent modifications or replacements without violating the spirit of the present invention , these equivalent modifications or replacements are all included within the scope defined by the claims of the present application.

Claims (5)

1. The gas hydrate solid fluidization excavation cavity flow field simulation device is characterized in that it includes: A flow field simulation device, a mixing device, a booster pump and a self-priming pump, the flow field simulation device includes a sealed box (11), a simulation pipe (12), a jet pipe (13) and a recovery pipe (14), the The first end of the jet tube (13) and the first end of the recovery tube (14) are respectively inserted into the inside of the sealed box (11), and the first end of the jet tube (13) is provided with a jet hole (131), the first end of the recovery pipe (14) is provided with a recovery hole (141), the jet tube (13) is used to guide the jet fluid into the sealed box (11), and the recovery tube (14) is used to guide mixed fluid to leave described sealing box (11), and described simulation tube (12) is installed in described sealing box (11), and simulation tube (12) can be designed into various geometric shapes to Simulate the excavation cavity with different structures, the jet hole (131) and the recovery hole (141) are located in the simulated tube (12), the simulated tube (12) is provided with a first pressure detection device, the A weight sensor is provided at the bottom of the sealed box (11); the inner space of the simulated pipe (12) communicates with the inner space of the sealed box (11), and the sealed box (11) is provided with an overflow valve, The sealed box (11) is provided with a second pressure detection device; The mixing device is used to mix the solid phase particles with the liquid phase, and the two ends of the booster pump are respectively connected to the second end of the mixing device and the jet tube (13), and the self-priming pump The two ends of are respectively connected to the second end of the recovery pipe (14) and the mixing device. 2. The gas hydrate solid fluidization mining cavity flow field simulation device according to claim 1, characterized in that: the sealed box (11) comprises a sealed box body (111) and an end cover (112), the The end cover (112) is detachably connected to one end of the sealed box body (111), and the simulation tube (12) can be taken out from the sealed box body (11). 3. The flow field simulation device of natural gas hydrate solid fluidization mining cavity according to claim 1, characterized in that: the number of the jetting holes (131) and the recovery holes (141) are both more than two. 4. The gas hydrate solid fluidization excavation cavity flow field simulation device according to claim 1, characterized in that: the sealed box (11) and the simulation pipe (12) are both made of transparent materials. 5. The experimental method based on any one of the natural gas hydrate solid fluidization mining cavity flow field simulation device in claims 1 to 4, characterized in that it comprises: S1. Make the simulated tube (12), determine the positions of the jet hole (131) and the recovery hole (141) in the sealed box (11), and the jet hole (131) and the Describe the arrangement, geometric shape and quantity of recovery holes (141); S2. setting a first pressure detection device on the inner wall of the simulated pipe (12); S3. Install the simulation tube (12), the jet tube (13) and the recovery tube (14) into the sealed box (11), seal the end face of the sealed box (11), Inject water into the sealed box (11) to fill its internal space, and check the tightness of the sealed box (11); S4. Open the mixing device to obtain a solid-liquid phase mixture; S5. Turn on the booster pump and the self-priming pump, form a flow field in the sealed box (11), and record the experimental data; S6. According to the real-time weight value of the weight sensor, the rate of change of the weight of the sealed box (11) over time is obtained, thereby calculating the deposition rate of solid phase particles in the sealed box (11), and then adjusting the weight of the sealed box (11). The mixing ratio of the mixing device and the output power of the booster pump; S7. Change the inner surface roughness, geometric shape, and geometric dimensions of the simulated pipe (12), the mixing ratio of the mixing device, the output power of the booster pump, the jet hole (131) and the At least one of the position, number, size, and overflow threshold of the overflow valve of the recovery hole (141), repeat the above S1 to S6.

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