An experimental device for increasing the production of low-rank coalbed methane

Abstract

The present invention relates to an experimental device for increasing the production of low-rank coalbed methane, comprising a suppression chamber, an experimental chamber and a gas transmission component, the gas transmission component comprising a support plate and a plurality of hollow functional tubes, the plurality of functional tubes being evenly arranged on the support plate, one end of the functional tube being open and passing through the support plate, and the other end being closed, a plurality of through holes being provided on the side of the functional tube for inputting gas and liquid; the suppression chamber comprises a frame serving as a chamber and a pressure-applying device, when suppressing the coal seam, the support plate is mounted on the bottom surface of the frame, and the functional tube is in the suppression chamber; the support plate supports a simulated coal seam, and the functional tube is in the simulated coal seam; the experimental chamber comprises a square chamber, two adjacent side surfaces and a top surface of the chamber are provided with a liquid bag 1 for filling with hydraulic oil to provide pressure for the simulated coal seam, during the experiment, the simulated coal seam is placed in the experimental chamber, the support plate serves as the side surface of the experimental chamber, and fracturing fluid and / or carbon dioxide and / or microbial liquid are input through the functional tube to facilitate the coal seam production increase experiment.

Description

Technical Field

[0001] The invention belongs to the technical field of coalbed methane production increase experiments, and in particular relates to an experimental device for increasing the production of low-rank coalbed methane. Background Art

[0002] Low-rank coalbed methane refers to coalbed methane found in low-rank coal seams such as lignite and long-smoke coal and their surrounding rocks. It has a high methane content and is a clean, high-quality energy source and chemical raw material. Low-rank coal has more large and medium pores and fewer small and micropores, resulting in high permeability and low adsorption. The adsorption and desorption of methane by low-rank coal are irreversible, that is, some methane molecules enter the interior of the coal matrix during the adsorption process, forming a "dead adsorption" state that is difficult to desorb. Low-rank coal also has good free gas storage capacity and therefore has broad development prospects. However, my country is currently in the research stage of low-rank coalbed methane development, with few industrial cases and a lack of effective experimental research equipment.

[0003] Furthermore, existing coalbed methane development experiments require the introduction of methane into a simulated coal seam until it reaches saturation with methane before proceeding. However, methane absorption in compressed simulated coal seams is slow, typically requiring 40-60 hours. This operation is time-consuming, energy-intensive, and results in low experimental efficiency. Summary of the Invention

[0004] To address the above problems, the present invention provides an experimental device for increasing the production of low-rank coalbed methane, comprising a suppression chamber, an experimental chamber, and a gas transmission assembly. The gas transmission assembly comprises a support plate and a plurality of hollow functional tubes, which are evenly arranged on the support plate. One end of the functional tube is open and passes through the support plate, while the other end is closed. The side of the functional tube is provided with a plurality of through holes for inputting gas and liquid into the coal seam.

[0005] The compression chamber includes a frame body and a pressure device. When compressing the coal seam, the support plate is installed on the bottom of the frame body, and the functional tube is placed in the compression chamber; the support plate supports the coal sample so that the functional tube is placed inside the simulated coal seam.

[0006] The experimental chamber includes a square chamber, and two adjacent sides and the top surface of the chamber are provided with liquid bags for filling with hydraulic oil to provide pressure for the simulated coal seam. During the experiment, the simulated coal seam is placed in the experimental chamber, and the support plate can serve as the side of the experimental chamber. Fracturing fluid and / or carbon dioxide and / or microbial liquid are input through the functional pipe to conduct coal seam production increase experiments.

[0007] The experimental apparatus of the present invention consists of two main parts. A simulated coal seam is pressed in a compression chamber. After forming, the coal seam is transferred to the experimental chamber for the yield-increasing experiment. In conventional techniques, the two chambers are complete, square chambers, each functioning independently. Gas pipes are connected to two opposing sides of the experimental chamber, respectively, for methane input and output, until the coal seam is saturated with methane adsorption. This adsorption process is lengthy, resulting in low experimental efficiency and high energy consumption. The present invention utilizes a single gas delivery component and evenly distributes functional pipes. The flexible support plate serves as both the bottom of the compression chamber and the side of the experimental chamber. During the compression of the coal seam, the support plate serves as the bottom of the compression chamber. Low-rank coal samples are placed in the compression chamber, naturally covering the functional pipes. This evenly distributes the functional pipes within the compressed simulated coal seam, facilitating the input of gases and liquids in subsequent experiments. The support plate supports the low-rank coal seam before it is placed in the experimental chamber, where it serves as one side of the chamber. During the experiment, several functional pipes are used to supply fracturing fluid, carbon dioxide, and / or microbial fluid to the coal seam, depending on the requirements of the experiment. Especially during the methane adsorption period of the coal seam, since the functional tubes are evenly distributed inside the coal seam, methane can be directly input into various positions inside the coal seam, which greatly improves the adsorption efficiency, greatly shortens the time of the adsorption step, and improves the experimental efficiency.

[0008] Optionally, the frame of the pressing bin is a cube having four side surfaces connected end to end, and the top and bottom surfaces are both empty; the support plate can support all the coal samples in the pressing bin;

[0009] The pressure device includes a pressing plate and a force-applying device. The pressing plate directly acts on the top surface of the coal sample in the pressing bin. The force-applying device is connected to the upper surface of the pressing plate and is used to press the pressing plate down to squeeze the coal sample into shape.

[0010] Optionally, the gas delivery assembly further includes a partitioning component for dividing the simulated coal seam saturated with methane adsorption into several blocks in the experimental chamber to facilitate simultaneous execution of multiple experiments;

[0011] The separation component includes a separation mesh and a separation liquid sac net. The separation mesh includes several metal plates intersecting horizontally and vertically, and is used to cut the simulated coal seam. The initial position of the separation mesh is on the inner side of the support plate facing the coal sample. The separation liquid sac net includes several liquid sacs intersecting horizontally and vertically. The initial position of the head of the separation liquid sac net penetrates the support plate, so that the other parts of the separation liquid sac net are on the outer side of the support plate away from the coal sample.

[0012] The head of the separation mesh is detachably connected to the traction mechanism outside the experimental chamber through a steel wire, and the tail of the separation mesh is connected to the head of the separation liquid sac net.

[0013] Further optionally, the plurality of metal plates of the separation mesh form a horizontal and vertical cross pattern along the horizontal direction and the vertical direction, so that the separation mesh can divide the simulated coal seam into a plurality of square blocks, each of which is tested separately and different experimental parameters are implemented.

[0014] Further optionally, the several liquid capsules 2 of the separating liquid capsule net form a horizontal and vertical cross form along the horizontal direction and the vertical direction respectively, so that the separating liquid capsule net can be located between the several square blocks of the simulated coal seam to play a barrier role; the tail of the liquid capsule 2 is connected to the infusion tube for inputting hydraulic oil into the liquid capsule 2, which can isolate the several square blocks of the simulated coal seam.

[0015] Further optionally, the head of the separation mesh is also provided with a separation wire mesh, which includes several horizontal and vertical crossing cutting wires for cutting the coal seam; at least one cutting wire is provided in front of the head of each metal plate, and the metal plate is parallel to the corresponding cutting wire.

[0016] Further optionally, during the experiment, the simulated coal seam is divided into several square blocks arranged in a matrix, and at least two steel wires are provided in the dividing surfaces corresponding to adjacent blocks. The steel wires are arranged horizontally, and the tails of the steel wires are connected to the corresponding cutting steel wires and the heads of the metal plates in sequence. The heads of the steel wires penetrate the coal seam along the width direction of the coal seam, and are then connected to the traction mechanism outside the experimental chamber. The cutting steel wires and the metal plates are pulled by the steel wires to move in the coal seam, thereby cutting the coal seam.

[0017] Optionally, the support plate is square, and positions on the support plate corresponding to the positions separating the liquid capsule nets are provided with cross-sectional and longitudinal hollow strips, allowing the liquid capsule 2 to pass through the support plate and enter the interior of the experimental chamber.

[0018] Optionally, a detachable square pressure plate is provided on the outer side of the support plate. Before the separation liquid sac net separates the coal seam, the separation liquid sac net is located between the support plate and the pressure plate, and the pressure plate and the support plate are buckled together.

[0019] Optionally, the experimental chamber is a cube having a bottom surface, a removable top cover, and three vertical side walls connected end to end, wherein the first side wall, the second side wall, the third side wall, and the support plate are arranged in a circle in a clockwise or counterclockwise direction, and the lower surface of the top cover, the first side wall, and the inner wall of the second side wall are all provided with a liquid capsule 1;

[0020] The edge of the bottom surface of the experimental chamber is provided with a docking groove 1 corresponding to the position of the support plate, the edge of the upper surface of the top cover is provided with a docking groove 2 corresponding to the position of the support plate, and the edge of the inner side surface of the third side wall is provided with a docking groove 3 corresponding to the position of the support plate, which is used to dock the support plate and a vertical side edge of the pressure plate; the other vertical side edge of the support plate and the pressure plate is provided with a movable docking groove, and a sealing gasket is provided inside each docking groove for sealing the experimental chamber.

[0021] Further optionally, the side of the bottom of the experimental chamber corresponding to the docking groove one extends in the direction indicated by the end of the docking groove one to form a docking bottom plate, and the side of the top cover corresponding to the docking groove two extends in the direction indicated by the end of the docking groove two to form a docking top plate, and the docking bottom plate and the docking top plate are both slender strips, and are both horizontal and parallel to each other;

[0022] The docking bottom plate and the docking top plate are both provided with a plurality of hollow grooves, which are evenly arranged along the length direction of the docking bottom plate and the docking top plate, and the hollow grooves of the docking bottom plate and the docking top plate correspond one to one up and down;

[0023] The top of the outer side of the movable docking slot is provided with an upper insert that can move up and down, and the bottom is provided with a lower insert that can move up and down. After the movable docking slot is positioned, the upper insert is inserted into the corresponding hollow slot of the docking top plate, and the lower insert is inserted into the corresponding hollow slot of the docking bottom plate. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 The figure is a three-dimensional schematic diagram of the pressing chamber (the front side of the pressing chamber is omitted to facilitate viewing the interior of the pressing chamber);

[0025] Figure 2 It is a side view of the pressing bin;

[0026] Figure 3 is a top view of the support plate;

[0027] Figure 4 Schematic diagram of the partition component (when the second liquid capsule is deployed);

[0028] Figure 5 This is a schematic diagram of the experimental chamber (with partition components omitted);

[0029] Figure 6 A schematic diagram showing that the periphery of the support plate and the pressure plate is surrounded by four docking grooves;

[0030] Figure 7 It is a side view of the movable docking slot.

[0031] In the accompanying drawings, 1-pressing chamber, 2-experimental chamber, 3-support plate, 4-functional tube, 5-frame, 6-air outlet pipe, 7-liquid capsule 2, 8-metal plate, 9-steel wire, 10-cutting wire, 11-pad pressure plate, 12-top cover, 13-first side wall, 14-second side wall, 15-third side wall, 16-docking groove 1, 17-docking groove 2, 18-docking groove 3, 19-movable docking groove, 20-docking bottom plate, 21-docking top plate, 22-upper plug, 23-lower plug. DETAILED DESCRIPTION

[0032] This embodiment provides an experimental device for increasing the production of low-rank coalbed methane. Figure 1-Figure 7 As shown, it includes a pressing chamber 1, an experimental chamber 2 and a gas transmission component. The gas transmission component includes a support plate 3 and a plurality of hollow functional tubes 4. The plurality of functional tubes 4 are evenly arranged on the support plate 3. One end of the functional tube 4 is open and passes through the support plate 3, and the other end is closed. The side of the functional tube 4 is provided with a plurality of through holes for inputting gas and liquid into the coal seam.

[0033] The compression chamber 1 includes a frame 5 serving as a chamber and a pressure device. When compressing the coal seam, the support plate 3 can be installed on the bottom surface of the frame 5, and the functional tube 4 is located in the compression chamber 1; the support plate 3 supports the coal sample, so that the functional tube 4 is located inside the simulated coal seam;

[0034] The experimental chamber 2 includes a square chamber, and two adjacent sides and the top surface of the chamber are provided with a liquid bag 1, which can be filled with hydraulic oil to provide pressure for the simulated coal seam. During the experiment, the simulated coal seam is placed in the experimental chamber 2, and the support plate 3 serves as the side of the experimental chamber 2. Fracturing fluid and / or carbon dioxide and / or microbial liquid are input through the functional pipe 4 to conduct a coal seam production increase experiment.

[0035] Optionally, the frame 5 of the pressing bin 1 is a cube having four side surfaces connected end to end, and the top and bottom surfaces are both empty; the area of ​​the support plate 3 is not less than the bottom surface of the frame 5, and can support all coal samples in the pressing bin 1;

[0036] The pressure device includes a pressing plate and a force-applying device. The pressing plate directly acts on the top surface of the coal sample in the pressing bin 1. The force-applying device is connected to the upper surface of the pressing plate and is used to press the pressing plate downward to squeeze the coal sample into shape.

[0037] The pressing plate is equivalent to the detachable and movable top surface of the pressing chamber 1. The force applying device is a conventional device capable of applying pressure, such as a common mechanical pressure applying device.

[0038] Preferably, a support platform is provided below the pressing chamber 1 to support the support plate 3 and the pressing chamber 1. Because the support plate 3 and the frame 5 are separate components, when the force-applying device presses downward, the support plate 3 is subjected to force, and the support platform can withstand the pressure, ensuring the integrity of the support plate 3 and the frame 5. The support platform has through holes corresponding to the positions of the functional tubes 4 to prevent compression of the functional tubes 4.

[0039] Optionally, the gas delivery assembly further includes a partitioning component for dividing the simulated coal seam saturated with methane adsorption into several blocks in the experimental chamber 2 to facilitate simultaneous execution of multiple experiments;

[0040] The separation component includes a separation mesh and a separation liquid sac net. The separation mesh includes several metal plates 8 that intersect horizontally and vertically, and is used to cut the simulated coal seam. The initial position of the separation mesh is on the side of the support plate 3 facing the coal sample. The separation liquid sac net includes several liquid sacs 7 that intersect horizontally and vertically. The initial position of the head of the separation liquid sac net penetrates the support plate 3, so that the other parts of the separation liquid sac net are on the side of the support plate 3 away from the coal sample.

[0041] The head of the separation mesh is detachably connected to the traction mechanism outside the experimental chamber 2 through a steel wire 9, and the tail of the separation mesh is connected to the head of the separation liquid sac net.

[0042] Further optionally, the plurality of metal plates 8 of the separation mesh form a horizontal and vertical cross pattern along the horizontal direction and the vertical direction, so that the separation mesh can divide the simulated coal seam into a plurality of square blocks, each of which is tested separately and different experimental parameters are implemented.

[0043] Preferably, the thickness of the side of the metal plate 8 facing the coal seam is less than the thickness of the other parts of the metal plate 8, so that the front edge of the metal plate 8 forms a cutting edge, which is convenient for cutting the coal seam;

[0044] When the separator mesh is in the initial position, the tail of the separator mesh is on the side of the support plate 3 facing the coal sample (i.e., the inner side of the support plate 3), and the head of the separator mesh can be inserted into the coal seam. The distance between the head and the tail of the separator mesh (i.e., the width of the metal plate 8) is not greater than 5% of the width of the coal seam to avoid affecting the coal seam block experiment after separation.

[0045] Further optionally, the several liquid sacs 2 7 of the separating liquid sac net form a horizontal and vertical cross form along the horizontal direction and the vertical direction, so that the separating liquid sac net can be located between the several square blocks of the simulated coal seam to play a barrier role; the several liquid sacs 2 7 can be interconnected or not; the tail of the liquid sac 2 7 has a detachable connecting infusion tube for inputting hydraulic oil into the liquid sac 2 7, which can isolate the several square blocks of the simulated coal seam.

[0046] Optionally, the head of the separator mesh is further provided with a separator wire 9, which includes a plurality of cutting wires 10 arranged horizontally and vertically, for cutting the coal seam. At least one cutting wire 10 is provided in front of the head of each metal plate 8, and the metal plate 8 is parallel to the corresponding cutting wire 10. The spacing between the head of the metal plate 8 and the corresponding cutting wire 10 is extremely small, for example, 1-3 mm.

[0047] Further optionally, during the experiment, the simulated coal seam is divided into several square blocks arranged in a matrix, and at least two steel wires 9 are provided in the dividing surfaces corresponding to adjacent blocks. The tail ends of the steel wires 9 are connected to the corresponding cutting steel wires 10 and the heads of the metal plates 8 in sequence. The heads of the steel wires 9 pass through the coal seam along the width direction of the coal seam, and are then connected to the traction mechanism outside the experimental chamber 2. The cutting steel wires 10 and the metal plates 8 are pulled by the steel wires 9 to move in the coal seam, thereby cutting the coal seam.

[0048] As a specific embodiment, for the experimental chamber 2, the horizontal direction between the support plate 3 and the side of the chamber 2 opposite to the experimental chamber 2 corresponds to the width of the coal seam. Several functional tubes 4 are parallel to the width of the coal seam, with each functional tube 4 corresponding to a square block of the simulated coal seam. The functional tube 4 is located at the center of the corresponding block, and each block can be used for one experiment. On the support plate 3 side, along the width of the coal seam, the partitioning mesh and partitioning wire 9 mesh form a horizontal and vertical cross pattern, forming a matrix of square blocks, each corresponding to a square block of the simulated coal seam. The sides between adjacent square blocks are the partitioning planes, which can be horizontal or vertical. The coal seam square blocks near the six sides of the experimental chamber 2 have two horizontal and vertical partitioning planes, while the square blocks inside have four partitioning planes forming a square; each partitioning plane is perpendicular to the support plate 3. The portion of the partitioning plane facing the support plate 3 is a straight line. The metal plate 8 and the liquid sac 2 7 correspond to the straight lines of each partitioning plane, thus being inserted into the simulated coal seam to divide the coal seam into several square blocks. The line of the dividing surface is aligned with a steel wire 9 at each end, parallel to the width of the coal seam and perpendicular to the cutting wires 10 of the separating wire mesh. This allows for uniform force application, pulling the corresponding cutting wires 10 and metal plate 8 along the dividing surface, thereby cutting the coal seam. This in turn pulls and guides the second liquid capsule 7 into the corresponding gap in the dividing surface, making the second liquid capsule 7 a solid part of the dividing surface. After the second liquid capsule 7 is filled with hydraulic oil and expands, its two side surfaces tightly adhere to the coal seam blocks on either side, completely separating the several coal seam blocks.

[0049] Optionally, the support plate 3 is square, and a number of functional tubes 4 are evenly distributed in a matrix on the inner side of the support plate 3; the positions of the support plate 3 corresponding to the separation of the liquid capsule network are provided with horizontal and vertical cross hollow strips, allowing the liquid capsule 2 7 to pass through the support plate 3 and enter the interior of the experimental chamber 2.

[0050] Preferably, a sealing gasket is provided on the outer side surface of the support plate 3 corresponding to the upper and / or lower part of the horizontal hollow strip, and a sealing gasket is also provided on the outer side surface of the support plate 3 corresponding to the left and / or right side of the vertical hollow strip, so that when the horizontal or vertical liquid capsule 2 7 is pulled into the experimental chamber 2, the surface of the liquid capsule 2 7 rubs against the sealing gasket, and the sealing gasket blocks the hollow strip to minimize air leakage. At the same time, the sealing gasket also prevents the metal plate 8 from falling off the inner side surface of the support plate 3.

[0051] Optionally, a detachable square pressure plate 11 is provided on the outer side of the support plate 3, and the area of ​​the pressure plate 11 is equal to that of the support plate 3. Before the separation liquid sac net separates the coal seam, the separation liquid sac net is located between the support plate 3 and the pressure plate 11. The pressure plate 11 and the support plate 3 are buckled together and can be installed as a whole on the side of the experimental chamber 2 or the bottom of the pressing chamber 1 to improve the compressive strength of the support plate 3.

[0052] Further optionally, a circle of sealing gasket is provided on the edge of the inner side of the pressure plate 11. After the pressure plate 11 is buckled with the support plate 3, the sealing gasket closes the four edges between the pressure plate 11 and the support plate 3, thereby sealing the space between the pressure plate 11 and the support plate 3.

[0053] Further optionally, the cushion plate 11 is provided with a plurality of through holes, and the open end of the functional tube 4 and the infusion tube of the separation liquid sac network pass through the corresponding through holes, and the infusion tube is connected to an external hydraulic oil tank.

[0054] When compacting the simulated coal seam, the separating sac net is spread and folded against the hollow strips to facilitate the subsequent pulling of sac 2 (7). Outside sac 2 (7), a pressure plate (11) engages and snaps onto support plate (3). The space between pressure plate (11) and support plate (3) is extremely narrow, only accommodating the unfilled sac 2 (7). The pressure plate (11) and support plate (3) compress the sealing gasket between them, sealing the space between them. The infusion tube and functional tube (4) exit through pressure plate (11), where they are sealed.

[0055] Place the support plate 3 horizontally with the inner side of the support plate 3 facing upward, that is, the head of the partition mesh is facing upward, and the closed end of the functional tube 4 is facing upward. Place the pad plate 11 and the support plate 3 steadily on the support platform, dock and compact the frame 5 of the pressing bin 1 with the upper surface of the support plate 3, and ensure that there is no gap between the bottom edge of the frame 5 and the support plate 3 to prevent the coal sample in the pressing bin 1 from falling out of the gap. At this time, the partition mesh is at the bottom of the pressing bin 1, and the metal plate 8 is upright, sealing the bottom of the pressing bin 1 into several square areas. Several steel wires 9 are connected to the corresponding cutting wires 10 and the corresponding positions of the metal plates 8, and the steel wires 9 are upright. A bracket can be set at the top of the pressing bin 1, and the steel wires 9 are connected to the bracket for positioning. A through hole can also be set at the position of the pressure plate corresponding to the steel wire 9, and the steel wire 9 is passed through the pressure plate and then connected to the bracket above. The force-applying device can be set on the bracket and connected to the pressure plate below.

[0056] The coal sample is evenly loaded into the compression chamber 1, covering the separating mesh and the separating wires 9. Several of the wires 9 are also embedded in the coal seam, and the coal sample is slightly above the closed end of the functional tube 4. After loading, the compression plate covers the top of the coal seam. The force-applying device presses down on the compression plate to compact the coal sample and tighten the wires 9 to prevent bending or displacement, resulting in a simulated coal seam. At this point, the closed end of the functional tube 4 is a short distance from the top of the simulated coal seam, for example, 3-5 mm, and the bottom of the coal seam is in close contact with the support plate 3.

[0057] Move the pressure plate upward and remove it, loosen all the steel wires 9, move the frame 5 upward and remove it, and the pressure plate 11 and the support plate 3 as a whole support the simulated coal seam above and move it into the experimental chamber 2. Due to the support and connection of the partition mesh, the simulated coal seam is stably connected to the support plate 3.

[0058] Optionally, the experimental chamber 2 is a cube, having a bottom surface, a removable top cover 12 and three vertical side walls connected end to end, the first side wall 13, the second side wall 14, the third side wall 15 and the support plate 3 are sequentially connected end to end in a clockwise or counterclockwise direction and form a circle, and the lower surface of the top cover 12, the inner wall of the first side wall 13 and the second side wall 14 are provided with a liquid capsule 1, and the liquid capsule 1 covers the corresponding wall surface;

[0059] The edge of the bottom surface of the experimental chamber 2 is provided with a docking groove 16 corresponding to the position of the support plate 3, which is used to dock the bottom edge of the support plate 3 and the pressure plate 11; the edge of the upper surface of the top cover 12 is provided with a docking groove 17 corresponding to the position of the support plate 3, which is used to dock the top edge of the support plate 3 and the pressure plate 11; the edge of the inner surface of the third side wall 15 is provided with a docking groove 18 corresponding to the position of the support plate 3, which is used to dock the support plate 3 and one vertical side of the pressure plate 11; the other vertical side of the support plate 3 and the pressure plate 11 are provided with a movable docking groove 19, and a sealing gasket is provided inside each docking groove for sealing the experimental chamber 2.

[0060] Docking slot 1 16 and docking slot 2 17 are horizontal, while docking slot 3 18 and movable docking slot 19 are vertical. The side of the movable docking slot 19 facing the support plate 3 is the inner side surface, which is parallel to the inner wall of the first side wall 13. The edge of the lower surface of the top cover 12 is provided with sealing strips, which correspond to the top of the first side wall 13, the second side wall 14, and the third side wall 15 respectively. The top edges of the support plate 3 and the pressure plate 11 are inserted into the docking slot 2 17, so that the top cover 12 seals the top of the experimental chamber 2. The bottom edges of the support plate 3 and the pressure plate 11 are inserted into the docking slot 16, and the two side edges of the support plate 3 and the pressure plate 11 are respectively inserted into the docking slot 3 18 and the movable docking slot 19, so that the side and bottom surfaces of the experimental chamber 2 are sealed.

[0061] Further optionally, the starting end of the docking groove 16 is fixedly docked and connected to the bottom end of the docking groove 3 18, and the starting end of the docking groove 2 17 can be movably connected to the top end of the docking groove 3 18, so as to facilitate the support plate 3 and the pressure plate 11 to move a small amount in the oblique downward direction toward the third side wall 15 under the pressure of the experimental chamber 2.

[0062] Further optionally, the side of the bottom of the experimental chamber 2 corresponding to the docking groove 16 extends in the direction indicated by the end of the docking groove 16 to form a docking bottom plate 20, and the side of the top cover 12 corresponding to the docking groove 2 17 extends in the direction indicated by the end of the docking groove 2 17 to form a docking top plate 21, and the docking bottom plate 20 and the docking top plate 21 are both slender strips, and are both horizontal and parallel to each other;

[0063] The docking bottom plate 20 and the docking top plate 21 are both provided with a plurality of hollow grooves, which are evenly arranged along the length direction of the docking bottom plate 20 and the docking top plate 21, and the hollow grooves of the docking bottom plate 20 and the docking top plate 21 correspond one to one up and down;

[0064] An upper insert 22 that can move up and down is provided at the top of the outer side surface of the movable docking groove 19, and a lower insert 23 that can move up and down is provided at the bottom. After the movable docking groove 19 is positioned, the upper insert 22 is inserted into the corresponding hollow groove of the docking top plate 21, and the lower insert 23 is inserted into the corresponding hollow groove of the docking bottom plate 20.

[0065] The functional tubes 4 of the present invention are inserted into the simulated coal seam through the support plate 3 and the pressure plate 11, and the functional tubes 4 are in the experimental chamber 2. When the three liquid bags are filled with hydraulic oil and pressure is applied to the coal seam, the coal seam is pushed toward the bottom surface, the third side wall 15 and the support plate 3, so that the six sides of the coal seam are in close contact with the three liquid bags, the bottom surface of the experimental chamber 2, the third side wall 15 and the support plate 3. In the traditional experimental box, there are no pipes in the coal seam, and there is no problem for the coal seam alone to be pushed by pressure. However, in the present invention, several functional tubes 4 are inserted into the coal seam to input methane, and can also simulate the input of fracturing fluid into the underground well body to fracture the coal seam. It can also input nutrient solution containing methanogens, and can also extract coalbed methane after the well is blocked. If the coal seam and the functional tubes 4 are pressed by pressure according to the traditional experimental box form, the rigid connection between the functional tubes 4 and the support plate 3 and the pressure plate 11 may be damaged.

[0066] Therefore, the present invention is designed with three docking grooves, all of which are concave in shape and have sealing gaskets inside. The support plate 3 and the pressure plate 11 are moved from top to bottom and inserted into the docking groove 1 16 and the docking groove 3 18. At the same time, the simulated coal seam is placed in the experimental chamber 2. After the top cover 12 is buckled, the docking groove 2 17 also covers the top edge of the support plate 3 and the pressure plate 11. At this time, the experimental chamber 2 is closed. Hydraulic oil is input into the three liquid capsules. The liquid capsule 1 expands and squeezes the coal seam, applying pressure to the coal seam to simulate the formation pressure, pressing the coal seam, the functional pipe 4, the support plate 3 and the pressure plate 11 downward at an angle. Due to the flexible sealing gaskets in the docking groove 16 and the docking groove 3 18, a small movement margin is provided. At the same time, the top cover 12 is flexible and can lead the docking groove 2 17 to press the top edge of the support plate 3 and the pressure plate 11 downward.

[0067] The movable docking groove 19 is sandwiched between the docking bottom plate 20 and the docking top plate 21, and can adapt to the movement of the support plate 3 and the pressure plate 11, that is, move toward the third side wall 15, ensuring that the inner side of the movable docking groove 19 tightly presses the side edges of the support plate 3 and the pressure plate 11. After moving into place, the upper and lower inserts 23 of the movable docking groove 19 are respectively inserted into the appropriate hollow grooves of the docking top plate 21 and the docking bottom plate 20, thereby fixing the movable docking groove 19. The side surfaces of the movable docking groove 19 correspond to the side surfaces of the first side wall 13, and they can be sealed in a conventional manner. Moreover, the first side wall 13, the docking bottom plate 20 and the bottom surface are integrated, so this sealing is not difficult.

[0068] After pressurizing and sealing the experimental chamber 2, the outer surface of the second sidewall 14 is sealed, and methane is introduced into the coal seam through several functional pipes 4. A gas outlet pipe 6 is provided on the third sidewall 15 for exhausting the gas. When the methane content in the exhaust gas is detected to be stable, indicating that the coal seam is saturated with methane adsorption, the methane flow is stopped and the gas outlet pipe 6 is sealed. During methane adsorption, the coal seam remains a single piece, and methane is introduced simultaneously by several functional pipes 4. Methane diffuses and migrates throughout the coal seam, and the functional pipes 4 cooperate with each other to accelerate the adsorption process.

[0069] The present invention has several functional tubes 4, which can perform experimental operations separately. The partition component can cut the coal seam into several blocks after the coal seam is saturated with methane, while ensuring that the liquid bag is continuously pressurized to maintain the sealing of the experimental chamber 2.

[0070] Optionally, the liquid capsule of the second side wall 14 is composed of several sub-capsules, which correspond one-to-one to the square blocks of the coal seam. A through hole is provided in the second side wall 14 at the position corresponding to the steel wire 9, so that the steel wire 9 passes through the experimental chamber 2, and the position through which it passes is sealed.

[0071] When the coal seam is just loaded into the experimental chamber 2, the previous top surface of the coal seam becomes the side surface, and the steel wire 9 faces the second side wall 14. Each steel wire 9 avoids the sub-bag, passes through the second side wall 14, and is connected to an external traction mechanism, such as a winder. Several winders are arranged up and down, and their rotating shafts are arranged horizontally. A row of several steel wires 9 are respectively connected to several corresponding positions of the rotating shaft, and one rotating shaft drives a row of steel wires 9 to move synchronously.

[0072] After the coal seam is saturated with methane, (several) winding machines pull all the steel wires 9 outward synchronously, keeping all the steel wires 9 horizontal, driving the separation wire 9 mesh to translate toward the second side wall 14. The cutting wire 10 moves within the coal seam, cutting the coal seam, followed by the separation mesh. The head of the metal plate 8 continues to cut the coal seam, cutting a gap at the separation surface. This then drives the separation liquid sac mesh to translate, and the liquid sac 2 7 enters the gap of the corresponding separation surface. The liquid sac 2 7 between the support plate 3 and the pressure plate 11 is gradually drawn into the coal seam. When the tail end of the liquid sac 2 7 just moves to the inner side of the support plate 3 (just off the inner side of the support plate 3), it means that the liquid sac 2 7 has completely separated the various blocks of the coal seam. At this time, hydraulic oil is input into the liquid sac 2 7 to completely seal the various blocks. At the same time, the tail end of the liquid sac 2 7 is tightly attached to and seals the inner side of the support plate 3, preventing liquid and gas from mixing between the various blocks. At this time, the separating wire mesh 9 moves and squeezes into the gaps between the sub-capsules, and the front end of the separating mesh also contacts the edge of each sub-capsule, that is, the edge of the sub-capsule squeezes the front edge of the metal plate 8. Under the action of the sub-capsule, the end of each block facing the second side wall 14 is closed to avoid liquid and gas leakage between the blocks.

[0073] When the steel wire 9 is pulled out, it's impossible to completely seal the through-holes on the outer surface of the second sidewall 14. Therefore, during the coal seam cutting and separation process (a short process, far shorter than the time it takes for adsorbed methane to reach equilibrium), methane continues to be introduced through the various functional pipes 4, while exhaust pipe 6 also exhausts gas to replenish the small amount of methane lost. Simultaneously, inert gas is gradually introduced into the space between the support plate 3 and the pressure plate 11 through the gas replenishment port on the pressure plate 11 to balance the air pressure. However, since the steel wire 9 passes between adjacent sub-cells, the liquid-filled sub-cells squeeze each other, effectively preventing gas escape.

[0074] During the experiment, each liquid bag is filled with hydraulic oil again, and the outer surface of the second side wall 14 is closed to reach the pressure required by the experiment. Then, according to the experimental plan, different types of fracturing fluids with different component concentrations are used for each functional tube 4, such as conventional fracturing fluid, fracturing with carbon dioxide and fracturing fluid, fracturing fluid containing methanogens and nutrient solution, fracturing with carbon dioxide and microbial nutrient solution and fracturing fluid, and other various combinations of fracturing forms. After fracturing, the functional tube 4 is closed and the well is blocked for a period of time. Then, gas is extracted through each functional tube 4 to collect, detect, and compare the differences in methane content in the coalbed methane produced by different coal seam blocks. Through the experimental device of the present invention, the purpose of studying the multiple effects of methane production increase and carbon dioxide storage effect under different combination conditions is achieved.

Claims

1. An experimental device for increasing the production of low-rank coalbed methane, characterized in that: It includes a compression chamber, an experimental chamber and a gas transmission component. The gas transmission component includes a support plate and a plurality of hollow functional tubes. The plurality of functional tubes are evenly arranged on the support plate. One end of the functional tube is open and passes through the support plate, and the other end is closed. The side of the functional tube is provided with a plurality of through holes for inputting gas and liquid into the coal seam. The pressing chamber includes a frame and a pressure device. A support plate can be installed on the bottom of the frame. The support plate supports the coal sample so that the functional tube is inside the simulated coal seam. The top surface and two adjacent sides of the experimental chamber are each provided with a liquid bag 1, which can be filled with hydraulic oil to provide pressure for the simulated coal seam. The support plate can serve as the side of the experimental chamber, and fracturing fluid and / or carbon dioxide and / or microbial liquid can be input through the functional pipe to conduct coal seam production increase experiments; The gas delivery assembly also includes a partitioning component for dividing the simulated coal seam saturated with methane adsorption into several blocks in the experimental chamber to facilitate simultaneous multiple experiments; The separation component includes a separation mesh and a separation liquid sac net. The separation mesh includes several metal plates intersecting horizontally and vertically, and is used to cut the simulated coal seam. The initial position of the separation mesh is on the inner side of the support plate facing the coal sample. The separation liquid sac net includes several liquid sacs intersecting horizontally and vertically. The initial position of the head of the separation liquid sac net penetrates the support plate, so that the other parts of the separation liquid sac net are on the outer side of the support plate away from the coal sample. The head of the separation mesh is detachably connected to the traction mechanism outside the experimental chamber through a steel wire, and the tail of the separation mesh is connected to the head of the separation liquid sac net.

2. The experimental device for increasing the production of low-rank coalbed methane according to claim 1, characterized in that: The frame of the pressing bin is a cube, having four side surfaces connected end to end, with the top and bottom surfaces being empty; the support plate can receive the coal sample in the pressing bin; The pressure device includes a pressing plate and a force-applying device. The pressing plate directly acts on the top surface of the coal sample in the pressing bin. The force-applying device is connected to the upper surface of the pressing plate and is used to press the pressing plate down to squeeze the coal sample into shape.

3. The experimental device for increasing the production of low-rank coalbed methane according to claim 1, characterized in that: The plurality of metal plates of the separation mesh are arranged in a horizontal and vertical direction to form a cross pattern, so that the separation mesh can divide the simulated coal seam into a plurality of square blocks, each of which is tested separately and with different experimental parameters; Several liquid sacs 2 of the separation liquid sac net form a horizontal and vertical cross-form along the horizontal and vertical directions, so that the separation liquid sac net can be located between several square blocks of the simulated coal seam to play a barrier role; the tail of the liquid sac 2 is connected to the infusion tube, which is used to input hydraulic oil into the liquid sac 2, which can isolate several square blocks of the simulated coal seam.

4. The experimental device for increasing the production of low-rank coalbed methane according to claim 3, characterized in that: The head of the separation mesh is also provided with a separation wire mesh, which includes several horizontal and vertical crossing cutting wires for cutting the coal seam; at least one cutting wire is provided in front of the head of each metal plate, and the metal plate is parallel to the corresponding cutting wire.

5. The experimental device for increasing the production of low-rank coalbed methane according to claim 4, characterized in that: During the experiment, the simulated coal seam was divided into several square blocks arranged in a matrix. At least two steel wires were installed in the dividing surfaces of adjacent blocks. The steel wires were arranged horizontally, and the tails of the steel wires were connected to the corresponding cutting wires and metal plate heads in sequence. The heads of the steel wires penetrated the coal seam along the width of the coal seam and were then connected to the traction mechanism outside the experimental chamber. The cutting wires and metal plates were pulled by the steel wires to move in the coal seam, thereby cutting the coal seam.

6. The experimental device for increasing the production of low-rank coalbed methane according to claim 5, characterized in that: The support plate is square, and the positions on the support plate corresponding to the separation of the liquid sac nets are provided with hollow strips that cross horizontally and vertically; A detachable square pressure plate is provided on the outer side of the support plate. Before the separation liquid sac net separates the coal seam, the separation liquid sac net is located between the support plate and the pressure plate, and the pressure plate and the support plate can be buckled into one.

7. The experimental device for increasing the production of low-rank coalbed methane according to claim 1, characterized in that: The experimental chamber is a cube having a bottom surface, a detachable top cover, and three vertical side walls connected end to end, wherein the first side wall, the second side wall, the third side wall, and the support plate are arranged in a circle in a clockwise or counterclockwise direction, and the lower surface of the top cover, the inner wall of the first side wall, and the inner wall of the second side wall are all provided with a liquid capsule 1; A docking groove 1 is provided on the bottom of the experimental chamber at the position corresponding to the support plate, a docking groove 2 is provided on the upper surface of the top cover at the position corresponding to the support plate, and a docking groove 3 is provided on the inner side of the third side wall at the position corresponding to the support plate; a movable docking groove is provided on the other vertical side of the support plate and the pressure plate, and a sealing gasket is provided inside each docking groove for sealing the experimental chamber.

8. The experimental device for increasing the production of low-rank coalbed methane according to claim 7, characterized in that: The bottom of the experimental chamber corresponds to the side of the docking groove one and extends in the direction indicated by the end of the docking groove one to become a docking bottom plate, and the side of the top cover corresponds to the side of the docking groove two and extends in the direction indicated by the end of the docking groove two to become a docking top plate; a plurality of hollow grooves are provided on the docking bottom plate and the docking top plate, and the hollow grooves correspond one to one above and below.

9. The experimental device for increasing the production of low-rank coalbed methane according to claim 8, characterized in that: The top of the outer side surface of the movable docking groove is provided with an upper plug piece that can move up and down, and the bottom is provided with a lower plug piece that can move up and down. After the movable docking groove is positioned, the upper plug piece is inserted into the corresponding hollow groove of the docking top plate, and the lower plug piece is inserted into the corresponding hollow groove of the docking bottom plate.

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