Natural gas hydrate exploitation and hydrate method CO2 storage test device and test method thereof

Abstract

The application discloses a natural gas hydrate exploitation and hydrate method CO2 storage test device and a test method thereof. The experimental device comprises a high-pressure reaction kettle, a rotating support system, a temperature control system, a data monitoring system, a gas-liquid collection system and an injection system. The rotating support system is connected with the high-pressure reaction kettle, so that the high-pressure reaction kettle can rotate by 360 degrees and be fixed after the high-pressure reaction kettle rotates to a predetermined angle. The temperature control system is used for providing a constant temperature environment for the high-pressure reaction kettle. The data monitoring system is used for monitoring data in the operation of the natural gas hydrate exploitation and hydrate method CO2 storage test device. The gas-liquid collection system is used for collecting gas and liquid in the high-pressure reaction kettle. The injection system is used for injecting substances required for tests into the high-pressure reaction kettle. The application has important significance for promoting commercialized exploitation of natural gas hydrate.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of marine natural gas hydrate exploitation and carbon capture, utilization and storage (CCUS), and particularly relates to a natural gas hydrate exploitation and hydrate method CO2 storage test device and a test method thereof. BACKGROUND

[0002] Natural gas hydrate is widely distributed in marine sediments and land permafrost. After combustion, it only produces a small amount of CO2 and water, which is much less polluting than traditional fossil energy such as coal and oil, and has nearly ten times higher energy density. The total amount of organic carbon resources contained in natural gas hydrate is huge, and it is generally regarded as a new type of clean energy. Therefore, it is of great significance to realize the commercial development of natural gas hydrate.

[0003] Under certain temperature conditions, CO2 hydrate requires lower pressure to remain stable than natural gas hydrate, and the formation conditions are more moderate. The phase equilibrium curve of hydrate in submarine sediments is mainly determined by depth, ocean thermal gradient and geothermal gradient. Therefore, by taking advantage of the difference between the phase equilibrium conditions of CO2 hydrate and natural gas hydrate, CO2 can be injected at appropriate depth and time to achieve hydrate method storage or assist natural gas hydrate exploitation: ① Before exploitation, CO2 is injected into the upper layer of the natural gas hydrate reservoir to form a CO2 hydrate cap to achieve artificial plugging; ② During exploitation, CO2 is injected into the natural gas hydrate enrichment area to achieve CO2 displacement exploitation; ③ After exploitation, CO2 is injected into the depleted natural gas hydrate reservoir to achieve geological restoration.

[0004] At present, the main technical means for studying natural gas hydrate exploitation and CO2 hydrate storage include indoor physical simulation and numerical analysis. The mainstream indoor physical simulation device is a fixed high-pressure reactor composed of a cylinder or a cube, which cannot accurately depict the vertical / horizontal spatial evolution of reservoir properties during accumulation, exploitation and storage, and can only simulate the second and third types of natural gas hydrate reservoirs, making it difficult to simulate the first type of reservoir, shallow gas layer and deep gas layer. In addition, the vertical / horizontal spatial evolution of CO2 hydrate / mixed hydrate in the upper part of the natural gas hydrate reservoir, the CO2 displacement exploitation process and the depleted natural gas hydrate reservoir is not clear. Therefore, how to study the natural gas hydrate exploitation scheme and CO2 hydrate storage strategy under indoor simulation conditions is a key problem that needs to be solved in the process of realizing the commercial exploitation of natural gas hydrate and CCUS.

[0005] It should be noted that the information disclosed in the above background section is only for understanding the background of the present application, and therefore can include information that does not constitute prior art known to those of ordinary skill in the art. Summary of the Invention

[0006] In view of the shortcomings of the prior art, the technical problem to be solved by the present invention is to provide a test device and test method for natural gas hydrate extraction and CO2 storage using the hydrate method.

[0007] The present invention adopts the following technical solution:

[0008] In a first aspect, the present invention provides a test apparatus for natural gas hydrate extraction and CO2 storage using the hydrate method, comprising a high-pressure reactor, a rotating support system, a temperature control system, a data monitoring system, a gas-liquid acquisition system, and an injection system; the rotating support system is connected to the high-pressure reactor to enable the high-pressure reactor to rotate 360° and to fix the high-pressure reactor after it has rotated to a predetermined angle;

[0009] The temperature control system is used to provide a constant temperature environment for the high-pressure reactor; the data monitoring system is used to monitor the data during the operation of the natural gas hydrate extraction and hydrate CO2 storage test device; the gas-liquid acquisition system is used to collect the gas and liquid in the high-pressure reactor; and the injection system is used to inject the substances required for the test into the high-pressure reactor.

[0010] Preferably, the high-pressure reactor includes 1-6 high-pressure reactor sub-reactors and a pressure cap. Each high-pressure reactor sub-reactor is connected to a rotating support system. The pressure cap is connected to one or both ends of the high-pressure reactor sub-reactor. The pressure cap includes a gas / hydraulic device, connecting pipes, and pressure cap valves. Through the rotating support system and the connecting pipes, the 1-6 high-pressure reactor sub-reactors are connected in series or in parallel in a predetermined shape. The injection system is also used to inject high-pressure gas / liquid through the gas / hydraulic device and pressure cap valves to compact the internal deposits of the high-pressure reactor sub-reactors.

[0011] Preferably, the predetermined shape is one of the following: a straight line, an L-shape, a T-shape, a cross shape, a star shape, and a three-shape.

[0012] Preferably, the temperature control system is used to provide a constant temperature environment within the range of -20 to 50°C for the high-pressure reactor.

[0013] Preferably, the data monitoring system comprises: a collecting module; a multi-point temperature sensor, a multi-point pressure sensor, a pressure sensor, a temperature sensor, a displacement sensor, a gas / liquid flow meter and an electronic scale, which are respectively connected with the collecting module; the multi-point temperature sensor and the multi-point pressure sensor are located at the body of the high-pressure reactor and are in communication with the high-pressure reactor; the pressure sensor, the temperature sensor and the gas / liquid flow meter are connected with the gas-liquid collecting system, and the displacement sensor is connected with the high-pressure reactor; and a computer connected with the collecting module.

[0014] Preferably, the gas-liquid collecting system comprises a back pressure valve, a gas-liquid separation tank and a gas collecting tank; the gas-liquid separation tank is in communication with the high-pressure reactor through the back pressure valve, the gas-liquid separation tank and the gas collecting tank are in communication, and the gas / liquid flow meter is connected between the back pressure valve and the high-pressure reactor; the electronic scale is arranged below the gas-liquid separation tank, and the temperature sensor and the pressure sensor are connected on the gas collecting tank.

[0015] Preferably, the injection system comprises a gas / liquid bottle, a booster pump, a liquid injection pump and an inlet and outlet valve; the gas / liquid bottle is connected with the booster pump, the booster pump is in communication with the liquid injection pump, and the booster pump and the liquid injection pump are both in communication with the high-pressure reactor through the inlet and outlet valve.

[0016] Preferably, a well shaft is further arranged in the high-pressure reactor, and the back pressure valve and the inlet and outlet valve are both in communication with the well shaft.

[0017] In the second aspect, the present application provides a test method for natural gas hydrate exploitation of the natural gas hydrate exploitation and hydrate method CO2 storage test device according to the first aspect, which comprises the following steps:

[0018] (1) rotating the high-pressure reactor to a vertical state by the rotating support system, pre-filling the mixture of water and sediments in the lower half of the high-pressure reactor, filling dry sediments in the upper half of the high-pressure reactor, and injecting high-pressure gas / liquid into the high-pressure reactor by the injection system to compact the sediments in the high-pressure reactor;

[0019] (2) injecting natural gas into the high-pressure reactor by the injection system to simulate the natural gas hydrate accumulation process;

[0020] (3) after the simulation is completed, rotating the high-pressure reactor by 180° by the rotating support system, and then adjusting the temperature and pressure in the high-pressure reactor to the actual seabed stratum conditions by the temperature control system and the injection system, thereby forming the first type of natural gas hydrate reservoir;

[0021] (4) Adjusting the pressure condition in the high-pressure reactor by the gas-liquid collection system, and realizing the exploitation of natural gas hydrate;

[0022] (5) If the driving force of natural gas hydrate decomposition is insufficient, at least one of hot water / steam, gas / liquid CO2, CO2-N2 mixed gas, CO2-H2 mixed gas, and inhibitor is injected into the high-pressure reactor in multiple times by the injection system, so as to improve the exploitation efficiency.

[0023] In a third aspect, the present application provides a test method for hydrate method CO2 storage, which is based on the hydrate method CO2 storage test device for natural gas hydrate exploitation according to the first aspect, and includes the following steps:

[0024] (1) Deposits are filled in the high-pressure reactor in advance, and the deposits in the high-pressure reactor are compacted by injecting high-pressure gas / liquid into the high-pressure reactor by the injection system;

[0025] (2) A predetermined amount of gas / liquid CO2, CO2-N2 mixed gas, and water are injected into the high-pressure reactor in multiple times by the injection system;

[0026] (3) The temperature condition in the high-pressure reactor is adjusted to the actual seabed stratum condition by the temperature control system, so as to realize the simulation of hydrate method CO2 storage;

[0027] (4) When the driving force of CO2 hydrate generation is insufficient, the promoter is injected into the high-pressure reactor in multiple times by the injection system, so as to improve the storage efficiency.

[0028] The present application has the beneficial effects that: the specially designed natural gas hydrate exploitation and hydrate method CO2 storage test device can adjust the angle of the high-pressure reactor by the rotating support system, so that it can accurately simulate the first type of natural gas hydrate reservoir, and in the further technical solution, the multiple sub-reactors are connected in series or parallel through the predetermined posture, which can simulate the natural gas hydrate accumulation process, the hydrate method CO2 storage process, the natural gas hydrate exploitation process, the multi-gas joint exploitation process, and the hydrate method CO2 storage in the depleted natural gas hydrate reservoir, which has important significance for promoting the commercial exploitation of natural gas hydrate. BRIEF DESCRIPTION OF DRAWINGS

[0029] Figure 1 The natural gas hydrate exploitation and hydrate method CO2 storage test device structure provided in the specific embodiment of the present application is shown in the schematic diagram;

[0030] Figure 2 The schematic diagram of one high-pressure reaction sub-reactor rotating to the vertical placement state in the embodiment 1 of the present application is shown in the schematic diagram;

[0031] Figure 3 Figure 1 is a schematic diagram of a high-pressure reactor in a horizontal state according to an embodiment of the present application;

[0032] Figure 4 Figure 2 is a schematic diagram of two high-pressure reactors in an L-shaped series connection state according to an embodiment of the present application;

[0033] Figure 5 Figure 3 is a schematic diagram of three high-pressure reactors in a T-shaped series connection state according to an embodiment of the present application;

[0034] Figure 6 Figure 4 is a schematic diagram of four high-pressure reactors in a cross-shaped series connection state according to an embodiment of the present application;

[0035] Figure 7 Figure 5 is a schematic diagram of six high-pressure reactors in a star-shaped series connection state according to an embodiment of the present application;

[0036] Figure 8 Figure 6 is a schematic diagram of three high-pressure reactors in a three-character-shaped parallel connection state according to an embodiment of the present application.

[0037] The reference signs are explained as follows:

[0038] 1 - high-pressure reactor; 1A / 1B / 1C - high-pressure reactor; 11 - screw hole; 12 - gland; 121 - gas / liquid pressure device; 2 - temperature control system; 3 - rotating support system; 41 - multi-point temperature sensor; 42 - multi-point pressure sensor; 43 - displacement sensor; 44 - gas / liquid flow meter; 45 - electronic scale; 46 - acquisition module; 47 - computer; 48 - pressure sensor; 49 - temperature sensor; 51 - wellbore; 52 - back pressure valve; 53 - gas-liquid separation tank; 54 - gas collection tank; 61 - gas / liquid bottle; 62 - booster pump; 63 - liquid injection pump; 71 - first inlet and outlet valve; 72 - second inlet and outlet valve; 73 - gland valve. DETAILED DESCRIPTION

[0039] The embodiments of the present application are described in detail below. It should be emphasized that the following description is only exemplary and is not intended to limit the scope of the present application and its applications, and the embodiments in the present application and the features in the embodiments can be combined with each other without conflict.

[0040] As Figures 1-8As shown, the embodiment of the present application provides a natural gas hydrate exploitation and hydrate method CO2 storage test device, which comprises a high-pressure reaction kettle 1, a rotating support system 3, a temperature control system 2, a data monitoring system, a gas-liquid collection system and an injection system; the rotating support system 3 is connected with the high-pressure reaction kettle for enabling the high-pressure reaction kettle to rotate by 360° and fixing the high-pressure reaction kettle after the high-pressure reaction kettle is rotated to a predetermined angle; the temperature control system 2 is used for providing a constant temperature environment for the high-pressure reaction kettle; the data monitoring system is used for monitoring data (such as real-time monitoring of temperature and pressure of each part of the device and the like) in the operation of the natural gas hydrate exploitation and hydrate method CO2 storage test device; the gas-liquid collection system is used for collecting gas and liquid in the high-pressure reaction kettle; and the injection system is used for injecting substances required for the test into the high-pressure reaction kettle.

[0041] In some embodiments, the high-pressure reaction kettle comprises 1-6 high-pressure reaction sub-kettles 1A, 1B, 1C and a gland 12, each high-pressure reaction sub-kettle is connected with one rotating support system, the gland 12 is connected at one end or both ends of the high-pressure reaction sub-kettle, the gland 12 comprises a gas / liquid pressure device 121, a communication pipeline 122 and a gland valve 73, through the rotating support system 3 and the communication pipeline 122, the 1-6 high-pressure reaction sub-kettles are connected in series or in parallel and penetrate each other in a predetermined shape, and the injection system is further used for injecting high-pressure gas / liquid through the gas / liquid pressure device 121 and the gland valve 73 to compact the internal deposits of the high-pressure reaction sub-kettle.

[0042] The high-pressure reaction sub-kettle can independently simulate natural gas hydrate accumulation, exploitation and hydrate method CO2 storage and the like. The high-pressure reaction sub-kettle can be cylindrical or columnar, with a length of 500-2000 mm and an inner diameter of 50-500 mm, but is not limited thereto, and can be connected and penetrated with each other through the communication pipeline of the gland. The rotating support system can be composed of a high-strength metal frame, can fix the high-pressure reaction sub-kettle, and realize 360° rotation of each kettle. The high-pressure gas / liquid can be injected through the gas / liquid pressure device in the gland via the gland valve 73 to compact the internal deposits of the high-pressure reaction kettle. The high-pressure reaction sub-kettle further comprises a threaded hole 11 for sealing and communicating with the outside.

[0043] In some embodiments, the predetermined shape is one of a straight line, an L shape, a T shape, a cross shape, a star shape, and a three-character shape. The high-pressure reaction sub-kettle can be used independently in a straight line state (2-6 high-pressure reaction sub-kettles, for example, 3 high-pressure reaction sub-kettles are used in parallel in a straight line), or multiple (2-6) high-pressure reaction sub-kettles can be used in combination in an L shape (2 high-pressure reaction sub-kettles), a T shape (3 high-pressure reaction sub-kettles), a cross shape (4 high-pressure reaction sub-kettles), and a star shape (5 or 6 high-pressure reaction sub-kettles), and the like, but are not limited thereto.

[0044] In some embodiments, the temperature control system 2 is used to provide a constant temperature environment for the high-pressure reaction kettle in the range of -20-50℃. Wherein, the temperature control system can be but is not limited to a constant temperature water bath, a constant temperature water bath jacket, a constant temperature air bath box, the temperature control range is -20-50℃, which can cover a single or multiple high-pressure reaction sub-kettles, and provide a constant temperature environment.

[0045] In some embodiments, 2-3 water bath jackets can be installed on the high-pressure reaction sub-kettle to simulate the geothermal gradient of the seabed formation under real conditions.

[0046] In some embodiments, the data monitoring system comprises: an acquisition module 46; a multi-point temperature sensor 41, a multi-point pressure sensor 42, a pressure sensor 48, a temperature sensor 49, a displacement sensor 43, a gas / liquid flow meter 44, and an electronic scale 45, which are respectively connected with the acquisition module 46; the multi-point temperature sensor 41 and the multi-point pressure sensor 42 are located on the kettle body of the high-pressure reaction kettle and are in communication with the high-pressure reaction kettle (for example, two groups of screw holes can be provided on both sides of the kettle wall of the high-pressure reaction kettle, each group of screw holes includes a plurality of screw holes, and the screw hole diameter is 10-200 mm, but is not limited thereto, the number and position of the screw holes can be set according to actual operation, and the screw holes that are not selected can be closed by pipe plugs); the pressure sensor 48, the temperature sensor 49, and the gas / liquid flow meter 44 are connected with the gas-liquid collection system, the displacement sensor 43 is connected with the high-pressure reaction kettle, and a computer 47 is connected with the acquisition module 46. Through the data monitoring system, the running conditions of each part of the device can be monitored in real time.

[0047] In some embodiments, the gas-liquid collection system is used to implement natural gas hydrate exploitation, including a back pressure valve 52, a gas-liquid separation tank 53 and a gas collection tank 54; the gas-liquid separation tank 53 is communicated with the high-pressure reactor through the back pressure valve 52, the gas-liquid separation tank 53 and the gas collection tank 54 are communicated, the gas / liquid flow meter 44 is connected between the back pressure valve 52 and the high-pressure reactor; the electronic scale 45 is arranged below the gas-liquid separation tank 53, and the temperature sensor 49 and the pressure sensor 48 are connected on the gas collection tank 54. A sampling valve is also arranged on the gas collection tank 54.

[0048] In some embodiments, the injection system can inject external gas / liquid into the high-pressure reactor, including a gas / liquid bottle 61, a booster pump 62, a liquid injection pump 63 (for example, a hand pump) and inlet and outlet valves 71 and 72; the gas / liquid bottle 61 is connected with the booster pump 62, the booster pump 62 is communicated with the liquid injection pump 63, and the booster pump 62 and the liquid injection pump 63 are both communicated with the high-pressure reactor through the inlet and outlet valves 71 and 72. Through the injection system, the high-pressure reactor can be injected with gas / liquid, including but not limited to hot water / steam, natural gas, CH4, gas / liquid CO2, N2, CO2-N2 mixed gas, CO2-H2 mixed gas, hydrate promoter and hydrate inhibitor.

[0049] In some embodiments, a wellbore 51 is further included, which is arranged in the high-pressure reactor, and the back pressure valve 52 and the inlet and outlet valves 71 and 72 are both communicated with the wellbore 51. The wellbore 51 can penetrate the inside of the high-pressure reactor, and the wellbore 51 can be a production well, an injection well and a monitoring well.

[0050] The embodiment of the present application further provides a test method for natural gas hydrate exploitation according to the natural gas hydrate exploitation and hydrate method CO2 storage test device, which includes the following steps:

[0051] (1) The high-pressure reactor is rotated to a vertical state by the rotating support system, the sediment mixed with water is pre-filled in the lower half of the high-pressure reactor, dry sediment is filled in the upper half of the high-pressure reactor, and high-pressure gas / liquid is injected into the high-pressure reactor by the injection system to compact the sediment in the high-pressure reactor;

[0052] (2) Natural gas is injected into the high-pressure reactor by the injection system to simulate the natural gas hydrate accumulation process;

[0053] (3) After the simulation is completed, the high-pressure reactor is rotated by 180° through the rotating support system, and then the temperature and pressure in the high-pressure reactor are adjusted to the actual seabed formation conditions through the temperature control system and the injection system, thereby forming a first type of natural gas hydrate reservoir;

[0054] (4) The pressure condition in the high-pressure reactor is adjusted through the gas-liquid collection system, and natural gas hydrate exploitation is realized.

[0055] (5) If the driving force for the decomposition of natural gas hydrate is insufficient, at least one of hot water / steam, gas / liquid CO2, CO2-N2 mixed gas, CO2-H2 mixed gas, and an inhibitor is injected into the high-pressure reactor in multiple times through the injection system to improve the exploitation efficiency.

[0056] The specific embodiment of the present application further provides a test method for hydrate method CO2 storage of the natural gas hydrate exploitation and hydrate method CO2 storage test device, which comprises the following steps:

[0057] (1) The sediment is pre-filled in the high-pressure reactor, and the sediment inside the high-pressure reactor is compacted by injecting high-pressure gas / liquid into the high-pressure reactor through the injection system;

[0058] (2) A predetermined amount of gas / liquid CO2, CO2-N2 mixed gas, and water is injected into the high-pressure reactor in multiple times through the injection system.

[0059] (3) The temperature condition in the high-pressure reactor is adjusted to the actual seabed formation condition through the temperature control system, and hydrate method CO2 storage simulation is realized.

[0060] (4) When the driving force for the generation of CO2 hydrate is insufficient, the promoter is injected into the high-pressure reactor in multiple times through the injection system to improve the storage efficiency.

[0061] The specific embodiment of the present application is further described below.

[0062] Example 1

[0063] The natural gas hydrate exploitation and hydrate method CO2 storage test device of the present embodiment is shown in FIG. 1, and the high-pressure reactor 1 (in this example, the high-pressure reactor sub-chamber 1B) can be in a single vertical or horizontal state. Figures 2-3

[0064] Figure 2 ​​The number of high-pressure reaction kettles 1 used is 1 and they are vertically placed. The lower half of the high-pressure reaction kettle 1B is filled with the sediment mixed with water, and the upper half is filled with dry sediment. Then, dry natural gas is injected through the wellbore 51 via the first inlet and outlet valve 71 to simulate the formation of natural gas hydrate. After the simulation is completed, the high-pressure reaction kettle 1B is rotated 180° by the rotating support system 3, and a first type of natural gas hydrate reservoir is formed.

[0065] (1) The number of high-pressure reaction kettles used is 1 and they are vertically placed. The lower half of the high-pressure reaction kettle 1B is filled with the sediment mixed with water (such as sand, soil), and the upper half is filled with dry sediment (such as sand, soil). Then, the sediment in the high-pressure reaction kettle 1B is compacted by injecting high-pressure gas / liquid through the gland valve 73 from the gas / liquid pressure device 121 inside the gland 12.

[0066] (2) Dry natural gas is injected through the wellbore 51 via the first inlet and outlet valve 71 to simulate the formation of natural gas hydrate.

[0067] (3) After the simulation is completed, the high-pressure reaction kettle 1B is rotated 180° by the rotating support system 3. Then, the temperature and pressure in the high-pressure reaction kettle 1B are adjusted to be close to the actual seabed formation conditions by the temperature control system 2 and the injection system, and a first type of natural gas hydrate reservoir is formed.

[0068] (4) The pressure conditions in the high-pressure reaction kettle 1B are adjusted by the back pressure valve 52 to achieve natural gas hydrate production.

[0069] (5) The gas and water production results are calculated by the changes in temperature and pressure of the electronic scale 45 and the gas collection tank 54.

[0070] (6) If the driving force for the decomposition of natural gas hydrate is insufficient, hot water / steam, gas / liquid CO2, CO2-N2 mixed gas, CO2-H2 mixed gas, inhibitors, etc. can be injected into the high-pressure reaction kettle 1B through the first inlet and outlet valve 71 via the wellbore 51 in multiple times by the gas / liquid bottle 61, the booster pump 62, and the liquid injection pump 63 to improve the production efficiency.

[0071] Example 2

[0072] The natural gas hydrate production and hydrate method CO2 storage test device of this embodiment is shown in Figure 4 The high-pressure reaction kettles 1A and 1B are connected in an L shape. The high-pressure reaction kettle 1A is used to simulate the overburden of natural gas hydrate, and the high-pressure reaction kettle 1B is used to simulate the reservoir of natural gas hydrate.

[0073] Example 3

[0074] The natural gas hydrate exploitation and hydrate method CO2 storage test device of the present embodiment is shown in Figure 5 Fig. 1A, 1B, 1C are connected in T shape, wherein the high-pressure reaction sub- autoclave 1A is used to simulate the overburden layer of natural gas hydrate, the high-pressure reaction sub- autoclave 1B is used to simulate the natural gas hydrate reservoir, and the high-pressure reaction sub- autoclave 1C is used to simulate the underburden layer of natural gas hydrate.

[0075] Example 4

[0076] The natural gas hydrate exploitation and hydrate method CO2 storage test device of the present embodiment is shown in Figure 6 Fig. 1A, 1B, 1C are connected in cross shape, wherein the high-pressure reaction sub- autoclave 1A is used to simulate the overburden layer of natural gas hydrate, the two high-pressure reaction sub- autoclaves 1B are used to simulate the natural gas hydrate reservoir, and the high-pressure reaction sub- autoclave 1C is used to simulate the underburden layer of natural gas hydrate.

[0077] Example 5

[0078] The natural gas hydrate exploitation and hydrate method CO2 storage test device of the present embodiment is shown in Figure 7 Fig. 1A, 1B, 1C are connected in star shape, wherein the high-pressure reaction sub- autoclave 1A is used to simulate the overburden layer of natural gas hydrate, the four high-pressure reaction sub- autoclaves 1B are used to simulate the natural gas hydrate reservoir, and the high-pressure reaction sub- autoclave 1C is used to simulate the underburden layer of natural gas hydrate.

[0079] Example 6

[0080] The natural gas hydrate exploitation and hydrate method CO2 storage test device of the present embodiment is shown in Figure 8 Fig. 1A, 1B, 1C are connected in star shape, wherein the high-pressure reaction sub- autoclave 1A is used to simulate the overburden layer of natural gas hydrate, the four high-pressure reaction sub- autoclaves 1B are used to simulate the natural gas hydrate reservoir, and the high-pressure reaction sub- autoclave 1C is used to simulate the underburden layer of natural gas hydrate.

[0081] In other embodiments, when the high-pressure reaction sub- autoclaves are connected in L shape, T shape, cross shape, and three-character shape, etc., all the high-pressure reaction sub- autoclaves can also be used to simulate the natural gas hydrate reservoir at the same time.

[0082] Example 7

[0083] The embodiment provides a test method of a natural gas hydrate exploitation and hydrate method CO2 storage test device, and particularly, for the embodiment 3, 4 or 5, the natural gas hydrate accumulation process and exploitation process simulation can be realized by the following steps:

[0084] (1) Deposits (such as sand, soil) are filled in each high-pressure reaction sub-kettle and the connecting pipe 122 in advance, and then the deposits in the high-pressure reaction sub-kettle are injected and compacted by the gas / liquid pressure device 121 in the pressure cover 12, the gas / liquid is injected from the pressure cover valve 73, and the deposits in the high-pressure reaction sub-kettle are injected and compacted by the gas / liquid pressure device 121 in the pressure cover 12.

[0085] (2) The gas / liquid bottle 61, the booster pump 62, the first inlet and outlet valve 71 or the second inlet and outlet valve 72, the wellbore 51 and the high-pressure reaction kettle 1B are sequentially connected, and a proper amount of natural gas and water is injected into the high-pressure reaction kettle 1B through the wellbore 51 in multiple times.

[0086] (3) The gas / liquid bottle 61, the booster pump 62, the liquid injection pump 63, the first inlet and outlet valve 71, the wellbore 51 and the high-pressure reaction sub-kettle 1A are sequentially connected, and a proper amount of water is injected into the high-pressure reaction sub-kettle 1A through the wellbore 51 by the first inlet and outlet valve 71, so as to simulate the natural gas hydrate overburden.

[0087] (4) The gas / liquid bottle 61, the booster pump 62, the first inlet and outlet valve 71, the wellbore 51 and the high-pressure reaction sub-kettle 1C are sequentially connected, and a proper amount of water or a proper amount of natural gas and water is injected into the high-pressure reaction sub-kettle 1C through the wellbore 51 by the first inlet and outlet valve 71, so as to simulate the underlying free gas layer (the underlying free gas layer is one of the natural gas hydrate overburden).

[0088] (5) The temperature condition in the high-pressure reaction sub-kettle 1B is adjusted by the temperature control system 2, so as to promote the generation of the natural gas hydrate.

[0089] (6) After the natural gas hydrate is generated to a certain saturation degree, the temperature and pressure in the high-pressure reaction sub-kettle 1A, 1B and 1C are adjusted to be close to the actual seabed stratum condition by the temperature control system 2 and the injection system 6, so as to realize the natural gas hydrate accumulation process simulation.

[0090] (7) The pressure condition in the high-pressure reaction sub-kettle 1B is adjusted by the back pressure valve 52, so as to realize the natural gas hydrate exploitation.

[0091] (8) The gas and water production results are calculated by the temperature and pressure changes of the electronic scale 45 and the gas collection tank 54.

[0092] In the embodiment, when the driving force of the natural gas hydrate decomposition is insufficient, hot water / steam, gas / liquid CO2, CO2-N2 mixed gas, CO2-H2 mixed gas, inhibitor and the like can be injected into the high-pressure reaction sub-kettle through the gas / liquid bottle 61, the booster pump 62 and the liquid injection pump 63, the first inlet and outlet valve 71 or the second inlet and outlet valve 72 and the wellbore 51 in multiple times, so as to improve the exploitation efficiency.

[0093] Example 8

[0094] The present embodiment provides a test method according to the natural gas hydrate exploitation and hydrate method CO2 storage test device, and specifically, the hydrate method CO2 storage simulation can be achieved by the following steps:

[0095] (1) The sediment (such as sand, soil) is pre-filled in each high-pressure reaction sub-pot, and then the sediment in the high-pressure reaction sub-pot is injected by the gas / liquid pressure device 121 in the pressure cover 12, from the pressure cover valve 73, to compact the sediment in the high-pressure reaction sub-pot;

[0096] (2) The appropriate amount of gas / liquid CO2, CO2-N2 mixed gas and water is injected into the high-pressure reaction sub-pot 1A, 1B and 1C through the wellbore 51 by the gas / liquid bottle 61, the booster pump 62, and the first inlet and outlet valve 71 or the second inlet and outlet valve 72 in multiple times;

[0097] (3) The temperature condition in each sub-pot is adjusted to the vicinity of the actual seabed formation condition by the temperature control system 2, to promote the generation of CO2 hydrate;

[0098] (4) When the driving force of CO2 hydrate generation is insufficient, the promoter can be injected into each high-pressure reaction sub-pot through the wellbore 51 by the gas / liquid bottle 61, the booster pump 62 and the liquid injection pump 63, through the first inlet and outlet valve 71 or the second inlet and outlet valve 72 in multiple times, to improve the storage efficiency.

[0099] In other embodiments, after the natural gas hydrate exploitation simulation completed in Example 7, the gas / liquid CO2 or CO2-N2 mixed gas with different proportions can be injected through the wellbore 51 by the first inlet and outlet valve 71 or the second inlet and outlet valve 72 to perform the hydrate method CO2 storage test simulation in the depleted natural gas hydrate reservoir.

[0100] In the above embodiments, the plurality of high-pressure reaction sub-pots are mutually penetrated in the attitudes of a linear type, an L type, a T type, a cross type, a star type and a three-character type, which can simulate the phase change heat and mass transfer process in the natural gas hydrate reservoir and the upper / lower overburden layer under the real working condition; the angle of the high-pressure reaction sub-pot is adjusted by the rotating support system, so that it can accurately simulate the first type of natural gas hydrate reservoir; in addition, the multi-gas joint mining process of the natural gas hydrate reservoir, the shallow gas layer and the deep gas layer can be simulated in the plurality of high-pressure reaction sub-pots respectively. The present application has important strategic significance for studying the promotion of commercial exploitation of natural gas hydrate.

[0101] The above further describes the present application in conjunction with specific / preferred embodiments, and cannot be deemed to limit the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application belongs, without departing from the concept of the present application, they can make several substitutions or variations to the described embodiments, and these substitutions or variations shall be deemed to fall within the protection scope of the present application. In the description of the present application, the description of the terms "an embodiment", "some embodiments", "a preferred embodiment", "an example", "a specific example", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are contained in at least one embodiment or example of the present application. In the present application, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner. In the case of no mutual contradiction, those skilled in the art can combine and combine the different embodiments or examples described in the present application and the features of the different embodiments or examples. Although the embodiments of the present application and their advantages have been described in detail, it should be understood that various changes, substitutions and modifications can be made herein without departing from the scope of protection of the patent application.

Claims

1. A natural gas hydrate production and hydrate method CO2 sequestration test apparatus, characterized by, The device comprises a high-pressure reactor, a rotating support system, a temperature control system, a data monitoring system, a gas-liquid collection system and an injection system. The rotating support system is connected to the high-pressure reactor to enable the high-pressure reactor to rotate 360° and fix the high-pressure reactor after it rotates to a predetermined angle. The temperature control system is used to provide a constant temperature environment for the high-pressure reactor. The data monitoring system is used to monitor data during the operation of the device. The gas-liquid collection system is used to collect gas and liquid in the high-pressure reactor. The injection system is used to inject substances required for the test into the high-pressure reactor. The high-pressure reactor comprises 2-6 high-pressure sub-reactors and a pressure cover. Each high-pressure sub-reactor is connected to a rotating support system to enable the high-pressure sub-reactor to rotate 360°. The pressure cover is connected to one end or both ends of the high-pressure sub-reactor. The pressure cover comprises a gas / liquid pressure device, a communication pipeline and a pressure cover valve. Through the rotating support system and the communication pipeline, the 2-6 high-pressure sub-reactors are connected in series or parallel in a predetermined shape to simulate, but not limited to, the formation of natural gas hydrate, the CO2 storage by hydrate method, the exploitation of natural gas hydrate, the multi-gas joint exploitation and the CO2 storage by hydrate method in depleted natural gas hydrate reservoirs. The injection system is also used to inject high-pressure gas / liquid through the gas / liquid pressure device and the pressure cover valve to compact the internal deposits of the high-pressure sub-reactor. The predetermined shape is one of L-shaped, T-shaped, cross-shaped, star-shaped and three-character-shaped. When the predetermined shape is L-shaped, the vertically upward high-pressure sub-reactor is used to simulate the overburden layer of natural gas hydrate and the horizontally downward high-pressure sub-reactor is used to simulate the reservoir of natural gas hydrate. When the predetermined shape is three-character-shaped, the first high-pressure sub-reactor at the top is used to simulate the natural gas hydrate reservoir, the second high-pressure sub-reactor in the middle is used to simulate the shallow gas layer and the third high-pressure sub-reactor at the bottom is used to simulate the deep gas layer to realize multi-gas joint exploitation.

2. The device according to claim 1, wherein: When the predetermined shape is T-shaped, the vertically upward high-pressure sub-reactor is used to simulate the overburden layer of natural gas hydrate, the horizontally middle high-pressure sub-reactor is used to simulate the reservoir of natural gas hydrate and the vertically downward high-pressure sub-reactor is used to simulate the underlying layer of natural gas hydrate. When the predetermined shape is cross-shaped, the vertically upward high-pressure sub-reactor is used to simulate the overburden layer of natural gas hydrate, the two horizontally high-pressure sub-reactors are used to simulate the reservoir of natural gas hydrate and the vertically downward high-pressure sub-reactor is used to simulate the underlying layer of natural gas hydrate. When the predetermined shape is star-shaped, the vertically upward high-pressure sub-reactor is used to simulate the overburden layer of natural gas hydrate, the four horizontally middle high-pressure sub-reactors are used to simulate the reservoir of natural gas hydrate and the vertically downward high-pressure sub-reactor is used to simulate the underlying layer of natural gas hydrate.

3. The natural gas hydrate production and hydrate method CO2 sequestration test apparatus of claim 1, wherein The temperature control system is used to provide a constant temperature environment in the range of-20-50 ℃ for the high-pressure reactor.

4. The natural gas hydrate production and hydrate method CO2 sequestration test apparatus of claim 1, wherein The data monitoring system comprises: a collecting module; a multi-point temperature sensor, a multi-point pressure sensor, a pressure sensor, a temperature sensor, a displacement sensor, a gas / liquid flow meter and an electronic scale connected with the collecting module respectively; the multi-point temperature sensor and the multi-point pressure sensor are located at the body of the high-pressure reactor and are in communication with the high-pressure reactor; the pressure sensor, the temperature sensor and the gas / liquid flow meter are connected with the gas-liquid collecting system, the displacement sensor is connected with the high-pressure reactor; and a computer connected with the collecting module.

5. The natural gas hydrate production and hydrate method CO2 sequestration test apparatus of claim 4, wherein The gas-liquid collecting system comprises a back pressure valve, a gas-liquid separation tank and a gas collecting tank; the gas-liquid separation tank is in communication with the high-pressure reactor through the back pressure valve, the gas-liquid separation tank and the gas collecting tank are in communication, and the gas / liquid flow meter is connected between the back pressure valve and the high-pressure reactor; the electronic scale is arranged below the gas-liquid separation tank, and the temperature sensor and the pressure sensor are connected on the gas collecting tank.

6. The natural gas hydrate production and hydrate method CO2 sequestration test apparatus of claim 5, wherein, The injection system comprises a gas / liquid bottle, a booster pump, a liquid injection pump and an inlet and outlet valve; the gas / liquid bottle is connected with the booster pump, the booster pump is in communication with the liquid injection pump, and the booster pump and the liquid injection pump are both in communication with the high-pressure reactor through the inlet and outlet valve.

7. The natural gas hydrate production and hydrate method CO2 sequestration test apparatus of claim 6, wherein Further comprising a well shaft arranged in the high-pressure reactor, and the back pressure valve and the inlet and outlet valve are both in communication with the well shaft.

8. A test method for natural gas hydrate production by the natural gas hydrate production and hydrate method CO2 storage test apparatus according to any one of claims 1 to 7, characterized by, The method comprises the following steps: (1) rotating the high-pressure reactor to a vertical state by the rotating support system, pre-filling the mixed sediment with water in the lower half of the high-pressure reactor, filling the dry sediment in the upper half of the high-pressure reactor, and injecting the high-pressure gas / liquid into the high-pressure reactor by the injection system to compact the sediment in the high-pressure reactor; (2) injecting the natural gas into the high-pressure reactor by the injection system to simulate the natural gas hydrate reservoir formation process; (3) after the simulation is completed, rotating the high-pressure reactor by 180° through the rotating support system, and then adjusting the temperature and pressure in the high-pressure reactor to the actual seabed formation conditions through the temperature control system and the injection system, so as to form the first type of natural gas hydrate reservoir; (4) adjusting the pressure condition in the high-pressure reactor through the gas-liquid collecting system, and realizing the exploitation of natural gas hydrate; (5) if the driving force of the natural gas hydrate decomposition is insufficient, at least one of hot water / steam, gas / liquid CO2, CO2-N2 mixed gas, CO2-H2 mixed gas and inhibitor is injected into the high-pressure reactor in multiple times through the injection system to improve the exploitation efficiency.

9. A test method for hydrate method CO2 sequestration of the natural gas hydrate production and hydrate method CO2 sequestration test apparatus according to any one of claims 1 to 7, characterized by, The method comprises the following steps: (1) pre-filling the sediment in the high-pressure reactor, and injecting the high-pressure gas / liquid into the high-pressure reactor through the injection system to compact the sediment in the high-pressure reactor; (2) injecting predetermined amounts of gaseous / liquid CO2, CO2-N2 mixed gas and water into the high-pressure reactor in batches through the injection system; (3) adjusting the temperature condition in the high-pressure reactor to the actual seabed formation condition through the temperature control system, so as to realize the simulation of CO2 storage by hydrate method; (4) when the driving force for generating CO2 hydrate is insufficient, injecting a promoter into the high-pressure reactor in batches through the injection system, so as to improve the storage efficiency.

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