Microwave Heating Simulation Experiment Device for Coal Reservoirs

Abstract

The present invention relates to the technical field of coalbed methane, and in particular to a simulation experimental device for microwave heating of a coal reservoir, aiming to solve the problem that there is currently no device that can relatively realistically simulate the microwave heating of a coal reservoir. The simulation experimental device for microwave heating of a coal reservoir includes a simulated reservoir system, a microwave heating system, a testing system, and a liquid production system. The microwave generator of the microwave heating system generates microwaves, and the microwaves are introduced into the coaxial cable through the coaxial cable inlet. The microwaves pass through the special holes of the copper pipe and directly reach the simulated reservoir system to heat the simulated reservoir system; the pump passes the water in the liquid storage tank into the simulated reservoir system through the water inlet for cooling; the water in the simulated reservoir system is filtered for impurities through the filter screen at the water outlet, then cooled by the radiator and returned to the liquid tank through the one-way valve to complete the cooling cycle. It has the advantages of environmental friendliness and convenient operation, can achieve selective heating, has uniform heating, and can relatively realistically simulate the microwave heating of a coal reservoir.

Description

Technical Field

[0001] The present invention relates to the technical field of coalbed methane, and particularly relates to a simulation experiment device for microwave heating of coal reservoirs. Background Art

[0002] As a new type of clean energy, the effective exploitation of coalbed methane can alleviate the current situation of tight energy resources. Coalbed methane is a hydrocarbon gas stored in coal reservoirs, mainly composed of methane, which is an associated mineral resource of coal and belongs to unconventional natural gas. Most of the coalbed methane is adsorbed on the surface of coal matrix particles, and a part of the coalbed methane is free in the coal pores or dissolved in the coalbed water. The gas supply capacity of coal seams is mainly determined by the original permeability of coal seams and engineering measures. There are many main controlling factors affecting the single-well production of coalbed methane, mainly including three aspects: geological conditions, engineering technology, and drainage control.

[0003] The permeability of coal reservoirs is extremely low. In order to improve the recovery rate of coalbed methane, hydraulic fracturing is a commonly used stimulation technology in the field. However, hydraulic fracturing technology may cause water resource waste, formation pollution, and microseismicity, and many countries and regions have prohibited the use of hydraulic fracturing. Therefore, it is necessary to seek a clean stimulation technology - microwave heating of coal reservoirs - to increase the reservoir temperature, eliminate the Jamin effect, increase the gas diffusion rate, and increase the critical desorption pressure of coalbed methane. In order to study the effect of microwave heating stimulation, a simulation experiment device for microwave heating of coal reservoirs is needed. However, at present, there is no device that can relatively truly simulate the microwave heating of coal reservoirs. Summary of the Invention

[0004] The present invention provides a simulation experiment device for microwave heating of coal reservoirs to solve the problem that there is currently no device that can relatively truly simulate the microwave heating of coal reservoirs.

[0005] To achieve the above object, the present invention provides a simulation experiment device for microwave heating of coal reservoirs, including a simulation reservoir system, a microwave heating system, a testing system, and a liquid production system. The microwave heating system is installed on the simulation reservoir system, the testing system is connected to the simulation reservoir system, and the liquid production system is connected to the simulation reservoir system.

[0006] In the above simulation experiment device for microwave heating of coal reservoirs, optionally, the simulation reservoir system includes a barrel body. The upper and lower ends of the barrel body are respectively fixedly installed with an upper flange plate and a lower flange plate through first screws. The upper flange plate is fixedly installed with an upper casing at the central position, and the lower flange plate is fixedly installed with a lower casing at the central position. A ceramic tube is fixedly installed between the upper casing and the lower casing. A water inlet is provided on the barrel body, and a water outlet is provided on the lower flange plate.

[0007] In the above simulation experiment device for microwave heating of coal reservoirs, optionally, two water outlets are symmetrically arranged on the lower flange plate, and a filter screen is arranged on the water outlets.

[0008] In the above-mentioned microwave heating simulation experimental device for coal reservoirs, optionally, four rows of water inlets are evenly distributed circumferentially on the cylinder body, each row includes three water inlets, and the water inlets are connected to the liquid production system.

[0009] In the above-mentioned microwave heating simulation experimental device for coal reservoirs, optionally, the water inlets are connected to the drainage tank.

[0010] In the above-mentioned microwave heating simulation experimental device for coal reservoirs, optionally, the microwave heating system includes a microwave generator, the microwave generator is connected to a rectangular waveguide, the rectangular waveguide is connected to a coaxial cable, the coaxial cable includes a small sleeve, the small sleeve is fixed to the upper sleeve by a second screw, the small sleeve is fixedly installed at the upper end of a copper tube, a copper core is installed at the central position of the copper tube, and an upper fixing device and a lower fixing device are installed between the copper tube and the copper core.

[0011] In the above-mentioned microwave heating simulation experimental device for coal reservoirs, optionally, both the upper fixing device and the lower fixing device are made of rubber material, the lower end face of the copper tube coincides with the upper end face of the lower fixing device, the inner side surface of the copper tube is coaxially fitted with the outer cylindrical surface of the lower fixing device, the lower end face of the copper core coincides with the bottom of the middle groove of the lower fixing device, the side surface of the copper core is coaxially fitted with the side surface of the middle groove of the lower fixing device, and the small sleeve is connected to the rectangular waveguide by a thread.

[0012] In the above-mentioned microwave heating simulation experimental device for coal reservoirs, optionally, the test system includes a pressure gauge, a thermometer, and a data processor. The pressure gauge is connected to the water inlets, the thermometer is installed at the bottom of the simulated reservoir system, and the data processor is respectively connected to the pressure gauge and the thermometer in signal.

[0013] In the above-mentioned microwave heating simulation experimental device for coal reservoirs, optionally, the liquid production system includes a filter. One end of the filter is connected to the water outlet, the other end of the filter is connected to a radiator, the radiator is connected to a liquid storage tank, the liquid storage tank is connected to a pump, the pump is connected to the water inlets, and the data processor is connected to the pump in signal.

[0014] In the above-mentioned microwave heating simulation experimental device for coal reservoirs, optionally, the radiator adopts a coil structure, and the coil pipeline of the radiator is made of Hastelloy material.

[0015] The microwave heating simulation experimental device for coal reservoirs provided by the present invention includes a simulated reservoir system, a microwave heating system, a testing system, and a liquid production system. The microwave heating system is installed on the simulated reservoir system. The testing system is connected to the simulated reservoir system, and the liquid production system is connected to the simulated reservoir system. The microwave generator of the microwave heating system generates microwaves, which are introduced into the coaxial cable through the coaxial cable inlet. The microwaves pass through the special holes of the copper pipe and directly reach the simulated reservoir system to heat the simulated reservoir system. The pump passes the water in the liquid storage tank through the water inlet into the simulated reservoir system for cooling. The water in the simulated reservoir system is filtered by the filter screen at the water outlet, then cooled by the radiator and returned to the liquid tank through the one-way valve to complete the cooling cycle. It has the advantages of being environmentally friendly and easy to operate, can achieve selective heating, has uniform heating, and can relatively realistically simulate the microwave heating of coal reservoirs.

[0016] The structure of the present invention and its other invention purposes and beneficial effects will become more obvious and understandable through the description of the preferred embodiments in conjunction with the accompanying drawings. Description of the Drawings

[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the accompanying drawings required for the description of the embodiments or the prior art. Obviously, the accompanying drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can also be obtained based on these drawings.

[0018] Figure 1 It is a schematic diagram of the overall structure of the microwave heating simulation experimental device for coal reservoirs provided by the embodiments of the present invention;

[0019] Figure 2 It is a schematic diagram of the structure of the simulated reservoir system of the microwave heating simulation experimental device for coal reservoirs provided by the embodiments of the present invention;

[0020] Figure 3 It is a schematic diagram of the structure of the microwave heating system of the microwave heating simulation experimental device for coal reservoirs provided by the embodiments of the present invention.

[0021] Explanation of the reference numerals in the drawings:

[0022] 1 - Simulated reservoir system; 2 - Microwave heating system; 4 - Rectangular waveguide; 5 - Microwave generator; 11 - Upper flange plate; 12 - Cylinder body; 13 - Ceramic tube; 14 - Water inlet; 15 - Water outlet; 16 - First screw; 17 - Lower flange plate; 18 - Lower casing; 19 - Upper casing; 21 - Coaxial cable inlet; 22 - Second screw; 23 - Small casing; 24 - Upper fixing device; 25 - Copper tube; 26 - Copper core; 27 - Coaxial cable outlet; 28 - Lower fixing device; 31 - Pressure gauge; 32 - Thermometer; 33 - Data processor; 34 - Flowmeter; 35 - Check valve; 36 - Stop valve; 41 - Filter; 42 - Radiator; 43 - Liquid storage tank; 44 - Pump; 45 - Drainage tank. Detailed implementation mode

[0023] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the embodiments of the present invention will be described in more detail below with reference to the accompanying drawings in the preferred embodiments of the present invention. In the drawings, the same or similar reference numerals denote the same or similar components or components with the same or similar functions throughout. The described embodiments are some, but not all, of the embodiments of the present invention. The embodiments described below by referring to the drawings are exemplary and are intended to explain the present invention and should not be construed as limiting the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts fall within the scope of protection of the present invention. The embodiments of the present invention will be described in detail below with reference to the drawings.

[0024] As Figures 1 - 3 shown, the present invention provides a coal reservoir microwave heating simulation experimental device, including a simulated reservoir system 1, a microwave heating system 2, a test system and a liquid production system. The microwave heating system 2 is installed on the simulated reservoir system 1, the test system is connected to the simulated reservoir system 1, and the liquid production system is connected to the simulated reservoir system 1.

[0025] It should be noted that the microwave heating system 2 generates microwaves and emits them to the simulated reservoir system 1 for microwave heating. The test system measures and records parameters such as temperature and pressure at various locations in the simulated reservoir system 1, and the liquid production system injects water into the simulated reservoir system 1 to change the dielectric constant of the coal.

[0026] Furthermore, the simulated reservoir system 1 includes a cylinder body 12. The upper and lower ends of the cylinder body 12 are respectively fixedly installed with an upper flange plate 11 and a lower flange plate 17 through first screws 16. The upper casing 19 is fixedly installed at the central position of the upper flange plate 11, the lower casing 18 is fixedly installed at the central position of the lower flange plate 17, the ceramic tube 13 is fixedly installed between the upper casing 19 and the lower casing 18, a water inlet 14 is provided on the cylinder body 12, and a water outlet 15 is provided on the lower flange plate 17.

[0027] It should be noted that ten threaded through holes are evenly distributed in the circumferential direction at both the upper and lower ends of the cylinder body 12. The lower end face of the upper flange plate 11 coincides with the upper end face of the cylinder body 12, and the upper flange plate 11 is coaxially fitted with the cylinder body 12. The upper end face of the upper flange plate 11 coincides with the lower surface of the flange of the upper sleeve 19. The middle through hole of the upper flange plate 11 is coaxially fitted with the outer side surface of the upper sleeve 19. The upper end face of the lower flange plate 17 coincides with the lower end face of the cylinder body 12, and the lower flange plate 17 is coaxially fitted with the cylinder body 12. The lower surface of the lower flange plate 17 coincides with the upper surface of the flange of the lower sleeve 18. The middle through hole of the lower flange plate 17 is coaxially fitted with the outer side surface of the lower sleeve 18.

[0028] Furthermore, two water outlets 15 are symmetrically arranged on the lower flange plate 17, and filter nets are installed on the water outlets 15.

[0029] It should be noted that the water outlet 15 is a through hole, and a filter net is installed on the water outlet 15 to filter impurities.

[0030] Furthermore, four rows of water inlets 14 are evenly distributed in the circumferential direction on the cylinder body 12. Each row includes three water inlets 14, and the water inlets 14 are connected to the liquid production system.

[0031] It should be noted that water inlets 14 are opened around the cylinder body 12, with one row set at an interval of 90°. Each row has three water inlets 14. The water inlets 14 are the inlets for the water pumped by the pump 44 and the outlets for the gas and water vapor generated during heating.

[0032] Furthermore, the water inlets 14 are connected to the drain tank 45.

[0033] It should be noted that the water inlets 14 are connected to the drain tank 45 through pipelines. The water vapor generated by the simulated reservoir system 1 is discharged through the water inlets 14 and enters the drain tank 45.

[0034] Furthermore, the microwave heating system 2 includes a microwave generator 5. The microwave generator 5 is connected to a rectangular waveguide 4. The rectangular waveguide 4 is connected to a coaxial cable. The coaxial cable includes a small sleeve 23. The small sleeve 23 is fixed to the upper sleeve 19 by a second screw 22. The small sleeve 23 is fixedly installed at the upper end of a copper tube 25. A copper core 26 is installed at the center position of the copper tube 25. An upper fixing device 24 and a lower fixing device 28 are installed between the copper tube 25 and the copper core 26.

[0035] It should be noted that the copper tube 25 and the copper core 26 are coaxially fitted. The coaxiality is ensured by the upper fixing device 24 and the lower fixing device 28. The copper tube 25 is provided with a microwave outlet of a special shape.

[0036] Further, both the upper fixing device 24 and the lower fixing device 28 are made of rubber material. The lower end face of the copper tube 25 coincides with the upper end face of the lower fixing device 28. The inner side surface of the copper tube 25 is coaxially fitted with the outer cylindrical surface of the lower fixing device 28. The lower end face of the copper core 26 coincides with the bottom of the middle groove of the lower fixing device 28. The side surface of the copper core 26 is coaxially fitted with the side surface of the middle groove of the lower fixing device 28. The small sleeve 23 is connected to the rectangular waveguide 4 by threads.

[0037] It should be noted that a coaxial cable inlet 21 is provided above the coaxial cable, and a coaxial cable outlet 27 is provided below the coaxial cable.

[0038] Further, the test system includes a manometer 31, a thermometer 32, and a data processor 33. The manometer 31 is connected to the water inlet 14. The thermometer 32 is installed at the bottom of the simulated reservoir system 1. The data processor 33 is respectively connected to the manometer 31 and the thermometer 32 in a signal connection.

[0039] It should be noted that the thermometer 32 is a thermocouple sensor. The thermometer 32 monitors the temperature of the simulated reservoir system 1 in real time and transmits the data to the data processor 33 for collection and processing. The test system is used to measure the temperature changes at various parts of the coal reservoir during the microwave heating process and display the values of parameters such as pressure, flow rate, and temperature collected by other sensors in real time. It also collects the parameters of the injection pump 44 in real time and controls the start, stop, and flow rate of the pump 44. It collects and calculates the produced oil, gas, and water data in real time, controls the flow path of the process flow, displays the liquid volume in the container in real time, gives a warning when the liquid volume in the container is completed, displays the working status of the control elements in real time, shows and prompts the user about the working process of each working stage, and gives an alarm for the upper limits of temperature and pressure.

[0040] Further, the liquid production system includes a filter 41. One end of the filter 41 is connected to the water outlet 15. The other end of the filter 41 is connected to a radiator 42. The radiator 42 is connected to a liquid storage tank 43. The liquid storage tank 43 is connected to a pump 44. The pump 44 is connected to the water inlet 14. The data processor 33 is connected to the pump 44 in a signal connection.

[0041] It should be noted that the water inlet 14 is connected to the pump 44 through a pipeline. A flow meter 34, a check valve 35, a stop valve 36, etc. are installed on the pipeline between the water inlet 14 and the pump 44. The liquid production system simulates the influence of downhole liquid production on heating, adopts the method of pressurization by a servo high-pressure pump, provides PLC control. The pump 44 is a plunger type electric pump, with a liquid crystal display, can automatically detect parameters such as injection pressure and flow rate, has an RS232 interface to realize connection with the data processor 33 (computer), and the pump head is made of stainless steel material.

[0042] Further, the radiator 42 adopts a coil type structure, and the coil pipeline of the radiator 42 is made of Hastelloy material.

[0043] It should be noted that both ends of the radiator 42 are the inlet and outlet of the cooling water, and the temperature of the liquid is controlled below 50°C after being cooled by the radiator 42.

[0044] For the microwave heating simulation experimental device of the coal reservoir of the present invention, the microwave propagation path is as follows: microwave generator 5 → rectangular waveguide 4 → coaxial cable inlet 21 → upper fixing device 24 → reflection on the inner wall of copper tube 25 → coaxial cable outlet 27 → ceramic tube 13 → coal reservoir; the circulating liquid inlet path is: liquid storage tank 43 → stop valve 36 → pump 44 → flowmeter 34 → check valve 35 → stop valve 36 → pressure gauge 31 → pipeline junction → coal reservoir; the circulating liquid return path is: coal reservoir → water outlet 15 → filter screen at water outlet 15 → pipeline → stop valve 36 → filter 41 → radiator 42 → check valve 35 → liquid storage tank 43.

[0045] For the microwave heating simulation experimental device of the coal reservoir of the present invention, its working principle is as follows: the microwave generator 5 generates microwaves, the microwaves are introduced into the coaxial cable through the coaxial cable inlet 21, and the microwaves pass through the special holes of the copper tube 25 and directly reach the simulated reservoir system 1 to heat the simulated reservoir system 1. The pump 44 injects the water in the liquid storage tank 43 into the simulated reservoir system 1 through the water inlet 14 for cooling. The water in the simulated reservoir system 1 is filtered for impurities through the filter screen at the water outlet 15, then cooled by the radiator 42 and returned to the liquid tank 43 through the check valve 35 to complete the cooling cycle.

[0046] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements on some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A simulation experimental device for microwave heating of coal reservoirs, characterized in that It includes a simulated reservoir system, a microwave heating system, a testing system and a liquid production system. The microwave heating system is installed on the simulated reservoir system. The testing system is connected to the simulated reservoir system, and the liquid production system is connected to the simulated reservoir system; The simulated reservoir system includes a cylinder body. The upper and lower ends of the cylinder body are respectively fixedly installed with an upper flange plate and a lower flange plate through first screws. An upper casing is fixedly installed at the central position of the upper flange plate, and a lower casing is fixedly installed at the central position of the lower flange plate. A ceramic tube is fixedly installed between the upper casing and the lower casing. A water inlet is provided on the cylinder body, and a water outlet is provided on the lower flange plate; Two water outlets are symmetrically arranged on the lower flange plate, and a filter screen is arranged on the water outlet; Four columns of water inlets are evenly distributed in a circumferential direction on the cylinder body. Each column includes three water inlets, and the water inlets are connected to the liquid production system; The water inlet is connected to a drainage tank; The microwave heating system includes a microwave generator. The microwave generator is connected to a rectangular waveguide, and the rectangular waveguide is connected to a coaxial cable. The coaxial cable includes a small sleeve. The small sleeve is fixed on the upper casing through a second screw. The small sleeve is fixedly installed at the upper end of a copper tube. A copper core is installed at the central position of the copper tube. An upper fixing device and a lower fixing device are installed between the copper tube and the copper core; Both the upper fixing device and the lower fixing device are made of rubber material. The lower end face of the copper tube coincides with the upper end face of the lower fixing device. The inner side surface of the copper tube is coaxially matched with the outer cylindrical surface of the lower fixing device. The lower end face of the copper core coincides with the bottom of the middle groove of the lower fixing device. The side surface of the copper core is coaxially matched with the side surface of the middle groove of the lower fixing device. The small sleeve is connected to the rectangular waveguide by threads.

2. The microwave heating simulation experimental device for coal reservoirs according to claim 1, wherein, The testing system includes a pressure gauge, a thermometer and a data processor. The pressure gauge is connected to the water inlet. The thermometer is installed at the bottom of the simulated reservoir system. The data processor is respectively signal-connected to the pressure gauge and the thermometer.

3. The microwave heating simulation experimental device for coal reservoirs according to claim 1, wherein, The liquid production system includes a filter. One end of the filter is connected to the water outlet, the other end of the filter is connected to a radiator, the radiator is connected to a liquid storage tank, the liquid storage tank is connected to a pump, the pump is connected to the water inlet, and the data processor is signal-connected to the pump.

4. The microwave heating simulation experimental device for coal reservoirs according to claim 3, wherein, The radiator adopts a coil type structure, and the coil pipeline of the radiator is made of Hastelloy material.

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