Experimental system for exploiting natural gas hydrate through self-generated heat fluid

Abstract

The utility model discloses an experiment system for exploiting natural gas hydrate by self-generated heat fluid, which comprises a multiphase fluid injection system, a reaction kettle, a cooler and a collection system, the injection end of the multiphase fluid injection system is communicated with an injection well shaft on the reaction kettle, and a jacket is arranged on the outer side wall of the reaction kettle; the two ends of the cooler are connected with the jacket through a first circulating guide pipe and a second circulating guide pipe respectively, a production well shaft on the reaction kettle is communicated with the collecting system through a guide pipe a, and a first ventilation pipe and a second ventilation pipe are arranged on the reaction kettle and the collecting system respectively. The first ventilation pipe and the second ventilation pipe are both communicated with the ventilation pipeline where the ventilation opening is located, and a data acquisition module is arranged on the reaction kettle. The self-heating fluid is injected into the reaction kettle according to the mixing proportion through the multi-phase fluid injection system, the temperature of the reaction kettle is adjusted through the cooler, and the data acquisition module detects the pressure and the temperature in real time in the experiment process, so that the accuracy and the comprehensiveness of the test are ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of natural gas hydrate exploitation, in particular to an experimental system for exploiting natural gas hydrates using autothermal fluid. Background Art

[0002] Natural gas hydrates (NGHs) are increasingly attracting attention from researchers worldwide for their cleanliness, abundant reserves, and secure supply. Under standard conditions, one cubic meter of solid NGHs can release approximately 180 cubic meters of natural gas. NGHs also possess a high energy storage capacity. Compared to other fossil fuels, natural gas produces the lowest carbon dioxide content per unit of combustion. Replacing coal with natural gas as the primary energy source will be a mitigation measure for reducing carbon dioxide emissions in the foreseeable future. It is estimated that the carbon content in NGHs worldwide is twice that of all confirmed fossil fuels on Earth. NGHs represent a clean, unconventional energy source with enormous potential for development and are therefore considered one of the key new energy sources of the 21st century.

[0003] In recent years, pilot production results have shown that depressurization mining has become the most promising mining method. However, this single mining method requires that the heat required for hydrate decomposition must be obtained from the sensible heat of the hydrate reservoir and heat transfer from the environment, which leads to a decrease in reservoir temperature and even ice formation and secondary hydrate formation, resulting in a serious decrease in hydrate extraction efficiency. Therefore, the autogenous thermal system method for hydrate extraction has been proposed. It has the advantages of in-situ thermal stimulation of hydrate extraction, low reactant cost (only 5.4 yuan / mol), and its injection process is almost unaffected by heat loss along the pipe flow and heat transfer between the pipe wall. In addition, both reactants and products are green and environmentally friendly products. However, there is a lack of research literature on the feasibility of autogenous thermal system extraction of hydrates. Some scholars have conducted preliminary macro-level analyses of the economic, environmental, and heat generation performance of different autogenous thermal systems, thus selecting ammonium salt and nitrite systems as the autogenous thermal system and using hydrochloric acid as the thermal catalyst as more suitable for hydrate extraction. However, during the simulation of hydrate extraction using an autothermal system, the chemical reaction system suffers from low mixing efficiency, preventing the ideal 1:1 mixing ratio for injection. Furthermore, the design and layout of the wellbore within the reactor, as well as the control and monitoring of pressure and temperature during the experiment, remain insufficiently precise. Furthermore, because the autothermal fluid contains acidic reactants and reacts violently, the corrosion resistance of the reaction vessel and the safety of the reaction also need to be considered during the device design. Therefore, after extensive research, the inventors developed an experimental system for extracting natural gas hydrates using autothermal fluids. Utility Model Content

[0004] The purpose of the utility model is to overcome the shortcomings of the prior art and provide an experimental system for exploiting natural gas hydrates using a self-generated thermal fluid.

[0005] The purpose of the utility model is achieved through the following technical solutions: an experimental system for the production of natural gas hydrates by self-generated thermal fluid, comprising a multiphase fluid injection system, a reactor, a cooler and a collection system, the injection end of the multiphase fluid injection system is connected to the injection wellbore on the reactor, and a jacket is installed on the outer wall of the reactor, the two ends of the cooler are respectively connected to the jacket through a first circulation conduit and a second circulation conduit, the production wellbore on the reactor is connected to the collection system through a conduit a, and the reactor and the collection system are respectively provided with a first ventilation pipe and a second ventilation pipe, the first ventilation pipe and the second ventilation pipe are both connected to the ventilation duct where the vent is located, the first ventilation pipe and the second ventilation pipe are both provided with corresponding control valves, and the reactor is provided with a data acquisition module.

[0006] Preferably, the multiphase fluid injection system includes a plunger pump, a storage tank group, a gas cylinder and a vacuum pump. The plunger pump is connected to the bottom of the storage tank group through a pipeline, a diverter valve is provided on the pipeline, the top of the storage tank group is connected to the injection wellbore through a corresponding pipeline, and the storage tank group is located in a constant temperature box. The gas cylinder is connected to the bottom of the reactor through an air pipe, a pressure reducing valve and a check valve a are installed on the air pipe, the vacuum pump is connected to the air pipe, and the vacuum pump is located between the check valve a and the reactor.

[0007] Preferably, the storage tank group includes storage tank a, storage tank b, storage tank c and storage tank d, and storage tank a, storage tank b, storage tank c and storage tank d are all located in a constant temperature box. Storage tank a and storage tank b are respectively connected to the six-way valve through the diversion conduit a and the diversion conduit b. A conduit b is also installed on the six-way valve. The other end of the conduit b is connected to the injection wellbore, and a check valve b is provided at the end of the conduit b. Storage tank c and storage tank d are respectively connected to the mixer through the diversion conduit c and the diversion conduit d, and the outlet of the mixer is connected to the conduit b.

[0008] Preferably, the collection system includes a gas-liquid separation device and a gas collection device. The wellbore of the production well is connected to the gas-liquid separation device through a conduit a. A filter, a pressure controller and a solenoid valve are sequentially provided on the conduit a, and a thermal insulation cotton layer is provided on the outside of the conduit a. The gas-liquid separation device and the gas collection device are connected through a conduit c. A dryer, a gas flow meter and a methane sensor are sequentially provided on the conduit c, and the pressure controller, solenoid valve, gas flow meter and methane sensor are all electrically connected to the PLC controller.

[0009] Preferably, the data acquisition module includes a pressure sensor a, a pressure sensor b and an armored thermocouple, the pressure sensor a is installed on the conduit b, the pressure sensor b is installed on the trachea, the armored thermocouple is arranged on the reactor, and the pressure sensor a, the pressure sensor b and the armored thermocouple are all electrically connected to the PLC controller.

[0010] Preferably, the armored thermocouple has three branches, and 2 to 4 temperature measuring points are set on each branch.

[0011] Preferably, each branch of the armored thermocouple is provided with an adjustment block.

[0012] Preferably, two supporting brackets are provided at the bottom of the reactor.

[0013] Preferably, a thermal insulation cotton layer is provided on the surface of the first circulation conduit.

[0014] Preferably, a plurality of circular holes are opened on the surface of the injection wellbore and the production wellbore.

[0015] The utility model has the following advantages: the utility model injects the autogenous heat fluid into the reactor according to the mixed ratio through the multiphase fluid injection system, and adjusts the temperature of the reactor through the cooler. During the experiment, the data acquisition module detects the pressure and temperature in real time, thereby ensuring the accuracy and comprehensiveness of the test. The device has a simple structure and provides the feasibility and convenience of the experimental device for the feasibility study of hydrate mining in the autogenous heat system. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 Schematic diagram of the experimental system;

[0017] Figure 2 It is a structural diagram of armored thermocouple;

[0018] Figure 3 It is a structural diagram of the injection wellbore and the production wellbore;

[0019] Figure 4 Schematic diagram of the structure of the upper layer of the mixer;

[0020] Figure 5 Schematic diagram of the structure of the lower layer of the mixer;

[0021] In the figure, 1-reactor, 2-cooler, 3-jacket, 4-first circulation conduit, 5-second circulation conduit, 6-conduit a, 7-first ventilation pipe, 8-second ventilation pipe, 9-vent, 10-ventilation duct, 11-plunger pump, 12-gas cylinder, 13-trachea, 14-vacuum pump, 15-check valve a, 16-storage tank a, 17-storage tank b, 18-storage tank c, 19-storage tank d, 20-diversion conduit a, 21-diversion conduit b, 22-six-way valve, 23-conduit b, 24-constant temperature box, 25- Diverter duct c, 26-diverter duct d, 27-mixer, 28-gas-liquid separation device, 29-gas collection device, 30-filter, 31-pressure controller, 32-solenoid valve, 33-dryer, 34-gas flow meter, 35-methane sensor, 36-duct c, 37-pressure sensor a, 38-pressure sensor b, 39-armored thermocouple, 40-PLC controller, 41-regulating block, 42-support bracket, 43-injection wellbore, 44-production wellbore, 45-circular hole, 46-pressure reducing valve. DETAILED DESCRIPTION

[0022] To make the purpose, technical solutions, and advantages of the embodiments of the present invention more clear, the technical solutions of the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Generally, the components of the embodiments of the present invention described and shown in the drawings herein can be arranged and designed in various different configurations.

[0023] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but rather merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by a person of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0024] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments can be combined with each other.

[0025] It should be noted that similar reference numerals and letters denote similar items in the following drawings, and therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings.

[0026] In the description of the present invention, it should be noted that the terms "center," "upper," "lower," "left," "right," "vertical," "horizontal," "inner," "outer," and the like, indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the product of the present invention is typically placed when in use, or are the orientations or positional relationships commonly understood by those skilled in the art. These terms are intended solely to facilitate the description of the present invention and to simplify the description, and are not intended to indicate or imply that the device or element referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and the like are used solely to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0027] It should also be noted that, in the description of this utility model, unless otherwise expressly specified or limited, the terms "disposed," "installed," "connected," and "connected" should be understood in a broad sense. For example, they can refer to fixed connections, detachable connections, or integral connections; mechanical connections, electrical connections; direct connections, indirect connections through an intermediate medium, and internal connections between two components. Those skilled in the art will understand the specific meanings of the above terms in this utility model based on the specific circumstances.

[0028] In this embodiment, if Figure 1As shown, an experimental system for extracting natural gas hydrates using autogenous thermal fluids includes a multiphase fluid injection system, a reactor 1, a cooler 2, and a collection system. The injection end of the multiphase fluid injection system is connected to the injection wellbore 43 on the reactor 1, and a jacket 3 is installed on the outer wall of the reactor 1. The two ends of the cooler 2 are respectively connected to the jacket 3 through a first circulation conduit 4 and a second circulation conduit 5. Preferably, a thermal insulation cotton layer is provided on the surface of the first circulation conduit 4. The production wellbore 44 on reactor 1 is connected to the collection system via conduit a6. A first ventilation pipe 7 and a second ventilation pipe 8 are respectively provided on reactor 1 and the collection system. Both the first ventilation pipe 7 and the second ventilation pipe 8 are connected to the ventilation duct 10 where the vent 9 is located. Each of the first ventilation pipe 7 and the second ventilation pipe 8 is equipped with a corresponding control valve. That is, when the pressure exceeds a set value, the corresponding control valve opens, discharging the overload gas through the first ventilation pipe 7 or the second ventilation pipe 8 into the ventilation duct 10, and finally out of the vent 9. Reactor 1 is equipped with a data acquisition module. In this embodiment, two support brackets 42 are provided at the bottom of reactor 1. A multiphase fluid injection system injects autogenous heat fluid into reactor 1 according to a mixing ratio, and the temperature of reactor 1 is regulated by cooler 2. During the experiment, the data acquisition module monitors the pressure and temperature in real time to ensure the accuracy and comprehensiveness of the test. This device has a simple structure and provides a feasible and convenient experimental device for feasibility studies of hydrate extraction using autogenous heat systems. In this embodiment, the cooler 2 is an existing product and has not been improved here, so it will not be described in detail.

[0029] Furthermore, the multiphase fluid injection system includes a plunger pump 11, a storage tank group, a gas cylinder 12 and a vacuum pump 14. The plunger pump 11 is connected to the bottom of the storage tank group through a pipeline, and a diverter valve is provided on the pipeline. The top of the storage tank group is connected to the injection wellbore 43 through a corresponding pipeline, and the storage tank group is located in a constant temperature box 24. The gas cylinder 12 is connected to the bottom of the reactor 1 through an air pipe 13, and a pressure reducing valve 46 and a check valve a15 are installed on the air pipe 13. The vacuum pump 14 is connected to the air pipe 13, and the vacuum pump 14 is located between the check valve a15 and the reactor 1. Furthermore, the storage tank group includes storage tank a16, storage tank b17, storage tank c18 and storage tank d19. Storage tank a16, storage tank b17, storage tank c18 and storage tank d19 are all located in a constant temperature box 24. Storage tank a16 and storage tank b17 are respectively connected to the six-way valve 22 through the diversion conduit a20 and the diversion conduit b21. A conduit b23 is also installed on the six-way valve 22. The other end of the conduit b23 is connected to the injection wellbore 43, and a check valve b is provided at the end of the conduit b23. Storage tank c18 and storage tank d19 are respectively connected to the mixer 27 through the diversion conduit c25 and the diversion conduit d26, and the outlet of the mixer 27 is connected to the conduit b23. Specifically, the materials installed in storage tank a16, storage tank b17, storage tank c18 and storage tank d19 are water, hydrochloric acid solution, ammonium chloride solution and sodium nitrite solution respectively. The vacuum pump 14 evacuates the interior of the reactor 1 through the air pipe 13. During the hydrate synthesis stage, the gas cylinder 12 fills the reactor 1 with high-purity methane gas at a constant pressure through the pressure reducing valve 46, the air pipe 13 and the check valve a15. The main function of the check valve a15 is to prevent gas backflow. During the hydrate extraction stage, the pipeline valve connected to the inlet of storage tank c18 and storage tank d19 is first opened, and then the solution in the liquid storage tank c18 and liquid storage tank d19 is pumped into the reactor 1 through the shunt pipe c25 and the shunting pipe c25 through the plunger pump 11. The diverter pipe d26 is pumped into the mixer 27 for mixing, and the mixed liquid then enters the injection well 43 through the pipe b23. Then, the pipe valves connected to the inlets of the storage tanks c18 and d19 are closed, and the pipe valves connected to the inlets of the storage tanks a16 and b17 are opened. The solution in the storage tanks a16 and b17 is pumped into the injection well 43 through the diverter pipe a20 or the diverter pipe b21, the six-way valve 22 and the pipe b23 by the plunger pump 11, thereby completing the feeding. In this embodiment, the plunger pump 11, the vacuum pump 14 and the mixer 27 are all existing products, and they are not improved here, so they will not be described in detail. The upper and lower layer structures of the mixer 27 are as shown in FIG. Figure 4 and Figure 5 shown.

[0030] In this embodiment, if Figure 3As shown, the surfaces of the injection wellbore 43 and the production wellbore 44 are each provided with a plurality of circular holes 45. Specifically, the upper portions of the injection wellbore 43 and the production wellbore 44 are hollow, connected to the check valve b and the conduit a6, respectively. The lower portions are solid and sealed, with micron-sized circular holes with a diameter of 3 μm uniformly formed in the middle, thereby facilitating the flow of gas and liquid within the reactor while preventing fine sand and gravel from entering the wellbore.

[0031] Furthermore, the collection system includes a gas-liquid separation device 28 and a gas collection device 29. The production wellbore 44 is connected to the gas-liquid separation device 28 via a conduit a6. A filter 30, a pressure controller 31, and a solenoid valve 32 are sequentially installed on conduit a6, and a thermal insulation layer is provided on the outside of conduit a6. The gas-liquid separation device 28 and the gas collection device 29 are connected via a conduit c36. A dryer 33, a gas flowmeter 34, and a methane sensor 35 are sequentially installed on conduit c36. The pressure controller 31, solenoid valve 32, gas flowmeter 34, and methane sensor 35 are all electrically connected to a PLC controller 40. Specifically, the filter 30 primarily prevents fine sand and gravel from entering the pressure controller 31 during the production of the multiphase fluid. The dryer 33 primarily dries out water and acidic solution carried by the produced gas to prevent damage to the gas flowmeter 34 and methane sensor 35. The pressure controller 31 primarily detects the pressure of the multiphase fluid produced by the reactor 1 as it flows through conduit a6. In this embodiment, the gas-liquid separation device 28, the gas collection device 29, the filter 30, the pressure controller 31, the dryer 33, the gas flow meter 34 and the methane sensor 35 are all existing products, which have not been improved here and will not be described in detail.

[0032] In this embodiment, the data acquisition module includes pressure sensor a37, pressure sensor b38, and armored thermocouple 39. Pressure sensor a37 is mounted on conduit b23, pressure sensor b38 is mounted on trachea 13, and armored thermocouple 39 is installed on reactor 1. Pressure sensor a37, pressure sensor b38, and armored thermocouple 39 are all electrically connected to a PLC controller 40. Specifically, pressure sensor a37, mounted on conduit b23, detects the pressure at the inlet of reactor 1, while pressure sensor b38, mounted on trachea 13, detects the injection pressure during methane gas injection. Furthermore, armored thermocouple 39 has three branches, each with two to four temperature measurement points, preferably two. Furthermore, each branch of armored thermocouple 39 is equipped with an adjustment block 41. Adjusting the position of the adjustment block 41 on the armored thermocouple 39 allows the height of the temperature measurement points on each branch to be adjusted.

[0033] Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions described in the aforementioned embodiments, or make equivalent substitutions for some of the technical features therein. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. An experimental system for natural gas hydrate production using autothermal fluid, characterized by: The invention comprises a multiphase fluid injection system, a reactor (1), a cooler (2) and a collection system, wherein the injection end of the multiphase fluid injection system is connected to the injection wellbore (43) on the reactor (1), and a jacket (3) is installed on the outer wall of the reactor (1), the two ends of the cooler (2) are connected to the jacket (3) through a first circulation conduit (4) and a second circulation conduit (5), respectively, the production wellbore (44) on the reactor (1) is connected to the collection system through a conduit a (6), and the reactor (1) and the collection system are respectively provided with a first ventilation pipe (7) and a second ventilation pipe (8), both of which are connected to a ventilation duct (10) where a ventilation port (9) is located, and corresponding control valves are provided on the first ventilation pipe (7) and the second ventilation pipe (8), and a data acquisition module is provided on the reactor (1).

2. The natural gas hydrate production experimental system using autothermal fluid according to claim 1, characterized in that: The multiphase fluid injection system comprises a plunger pump (11), a storage tank group and a gas cylinder (12) and a vacuum pump (14), wherein the plunger pump (11) is connected to the bottom of the storage tank group through a pipeline, a diverter valve is provided on the pipeline, the top of the storage tank group is connected to the injection wellbore (43) through a corresponding pipeline, and the storage tank group is located in a constant temperature box (24), the gas cylinder (12) is connected to the bottom of the reactor (1) through an air pipe (13), a pressure reducing valve (46) and a check valve a (15) are installed on the air pipe (13), and the vacuum pump (14) is connected to the air pipe (13), and the vacuum pump (14) is located between the check valve a (15) and the reactor (1).

3. The natural gas hydrate mining experimental system using autogenous thermal fluid according to claim 2 is characterized in that: The storage tank group includes a storage tank a (16), a storage tank b (17), a storage tank c (18) and a storage tank d (19). The storage tank a (16), the storage tank b (17), the storage tank c (18) and the storage tank d (19) are all located in the constant temperature box (24). The storage tank a (16) and the storage tank b (17) are connected to the six-way valve (22) through the shunt conduit a (20) and the shunt conduit b (21) respectively. The six-way valve (22) is further provided with a conduit b (23), the other end of which is connected to the injection wellbore (43), and a check valve b is provided at the end of the conduit b (23). The storage tank c (18) and the storage tank d (19) are respectively connected to the mixer (27) through a diversion conduit c (25) and a diversion conduit d (26), and the outlet of the mixer (27) is connected to the conduit b (23).

4. The natural gas hydrate production experimental system using autothermal fluid according to claim 1, characterized in that: The collection system includes a gas-liquid separation device (28) and a gas collection device (29). The production wellbore (44) is connected to the gas-liquid separation device (28) through the conduit a (6). A filter (30), a pressure controller (31) and a solenoid valve (32) are sequentially provided on the conduit a (6), and a heat-insulating cotton layer is provided on the outer side of the conduit a (6). The gas-liquid separation device (28) and the gas collection device (29) are connected through a conduit c (36). A dryer (33), a gas flow meter (34) and a methane sensor (35) are sequentially provided on the conduit c (36), and the pressure controller (31), the solenoid valve (32), the gas flow meter (34) and the methane sensor (35) are all electrically connected to a PLC controller (40).

5. The natural gas hydrate production experimental system using autogenous thermal fluid according to claim 4 is characterized in that: The data acquisition module includes a pressure sensor a (37), a pressure sensor b (38) and an armored thermocouple (39), wherein the pressure sensor a (37) is installed on the conduit b (23), the pressure sensor b (38) is installed on the air pipe (13), and the armored thermocouple (39) is arranged on the reactor (1), and the pressure sensor a (37), the pressure sensor b (38) and the armored thermocouple (39) are all electrically connected to the PLC controller (40).

6. The natural gas hydrate production experimental system using autothermal fluid according to claim 5, characterized in that: The armored thermocouple (39) has three branches, and 2 to 4 temperature measurement points are set on each branch.

7. The natural gas hydrate production experimental system using autothermal fluid according to claim 6, characterized in that: Each branch of the armored thermocouple (39) is provided with an adjustment block (41).

8. The natural gas hydrate production experimental system using autogenous thermal fluid according to claim 1, characterized in that: Two supporting brackets (42) are provided at the bottom of the reactor (1).

9. The natural gas hydrate production experimental system using autothermal fluid according to claim 1, characterized in that: The surface of the first circulation conduit (4) is provided with a heat-insulating cotton layer.

10. The natural gas hydrate production experimental system using autothermal fluid according to claim 1, characterized in that: A plurality of circular holes (45) are provided on the surfaces of the injection well bore (43) and the production well bore (44).

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