Shale gas desorption pressure testing device and method

Abstract

The invention belongs to the technical field of shale gas preparation, particularly relates to a shale gas desorption pressure testing device and method, and provides the following scheme aiming at the problem that an existing desorption pressure testing device cannot crush a shale sample in the testing device: the shale gas desorption pressure testing device comprises a box body, and one side of the box body is connected with a box door through a hinge; a handle is fixedly connected to the side, away from the box body, of the box door, a test box is fixedly connected to the inner wall of the bottom of the box body, a sealing door is connected to one side of the test box through hinges, a crushing and screening module is arranged in the test box and comprises a motor, and the output end of the motor is connected with a cam through a coupler. According to the shale gas desorption pressure testing device and method disclosed by the invention, a shale sample can be fully crushed in a state of being isolated from air in the device, and then is screened into required fine-mesh powder, so that the accuracy of desorption data of the shale sample in the device is ensured.

Description

Technical Field

[0001] The present invention relates to the technical field of shale gas preparation, and particularly to a shale gas desorption pressure testing device and method. Background Art

[0002] Shale gas desorption is a method for determining shale gas content, which refers to obtaining the actual gas content by measuring the desorption behavior of on-site drilling cores or representative cuttings. Shale gas content is an important parameter for calculating shale gas resource potential and reserve prediction, and is of great significance for shale gas exploration and development. A shale gas desorption instrument is used to detect the gas content of shale.

[0003] In existing desorption pressure testing devices, the shale samples used are often crushed and screened outside the testing equipment, which causes some of the shale gas in the crushed shale samples to disperse into the air during this process, resulting in an impact on the accuracy of the numerical values in the desorption test. Summary of the Invention

[0004] The present invention discloses a shale gas desorption pressure testing device and method, aiming to solve the technical problem that the existing desorption pressure testing device in the background art cannot crush shale samples inside the testing device.

[0005] A shale gas desorption pressure testing device proposed by the present invention includes a box body. One side of the box body is connected with a box door through a hinge. A handle is fixedly connected to the side of the box door away from the box body. The inner wall of the bottom of the box body is fixedly connected with a testing box. One side of the testing box is connected with a closing door through a hinge. A crushing and screening module is arranged inside the testing box. The crushing and screening module includes a motor. The output end of the motor is connected with a cam through a coupling. A rotating shaft is fixedly connected to the outside of the cam. A connecting rod is movably connected to the outside of the rotating shaft. A grinding pestle is movably connected to the bottom of the connecting rod. A mortar is slidably connected to the outside of the grinding pestle. A plurality of fine holes are arranged at equal circumferential intervals on the inner wall of the bottom of the mortar. A sealing module is arranged between the testing box and the closing door.

[0006] By providing the box body, the testing box, the closing door, the crushing and screening module and the sealing module, the device can use the crushing and screening module to fully crush the shale samples in a state of being isolated from the air in the device, and then screen them into the required fine powder, so as to ensure the accuracy of the desorption data of the shale samples in the device.

[0007] In a preferred embodiment, a base is fixedly connected to the inner wall of one side of the test chamber away from the closed door. The base is fixedly connected to the side opposite to the motor. A cutting groove is formed on the upper side of the connecting rod. A limiting shaft is slidably connected in the cutting groove. The limiting shaft is fixedly connected to the side opposite to the base. And the outside of the mortar is movably connected with a support frame. The bottom of the support frame is fixedly connected with a platform plate. A tray is arranged on the inner wall of the bottom of the support frame. An exhaust pipe is arranged on the upper side of the test chamber. An electric valve I is arranged on the outside of the exhaust pipe. One end of the exhaust pipe away from the test chamber passes through the box body and is located outside the box body. A vacuum pump is fixedly connected to the inner wall of the bottom of the box body. The output end of the vacuum pump is connected to the exhaust pipe through a conduit. Six symmetric springs I are fixedly connected to the outside of the mortar. One end of the spring I away from the mortar is fixedly connected to the same stabilizing frame. The bottom of the stabilizing frame is fixedly connected to the upper side of the platform plate. A receiving frame is slidably connected to the outside of the platform plate. Symmetric fitting blocks I and fitting blocks II are arranged in the receiving frame. The bottom of the fitting block I is movably connected to the inner wall of the bottom of the receiving frame. The upper side of the fitting block I is in contact with the fitting block II. The upper side of the fitting block II is fixedly connected to the bottom of the platform plate. And an arc-shaped groove is formed in the receiving frame. A connecting rod is slidably connected in the arc-shaped groove. A round hole is formed in the connecting rod. A pin is slidably connected in the round hole. A spring II is fixedly connected to the outside of the pin. One end of the spring II away from the pin is fixedly connected to the outside of the connecting rod. Two symmetric insertion seats are fixedly connected to the outside of the receiving frame. The outside of the pin is inserted into the inner wall of one of the insertion seats. And a fine hole is formed in the outside of the test chamber. A conveying pipe I is fixedly connected in the fine hole. One end of the conveying pipe I away from the test chamber is provided with a physiological saline tank. A round opening is formed in the upper side of the physiological saline tank. A conveying pipe II is fixedly connected in the round opening. One end of the conveying pipe II away from the physiological saline tank is provided with a storage tank. A suction pump I is arranged on the outside of the conveying pipe I. The outside of the suction pump I is fixedly connected to the outside of the test chamber. The output end of the suction pump I is connected to the conveying pipe I through a thin pipe. A suction pump II is fixedly connected to the outside of the test chamber. The output end of the suction pump II is connected to the conveying pipe II through a round pipe. And electric valves III and II are respectively arranged on the conveying pipe I and the conveying pipe II. A control panel is fixedly connected to the side of the closed door away from the test chamber.

[0008] By providing a crushing and screening module, the crushing and screening module can quickly and conveniently complete the grinding of shale samples by using a cam and a connecting rod. By using the provided fine pores, the ground shale powder can be kept uniform and regular, which helps the device release shale gas to the greatest extent during shale desorption, improves the desorption effect, and ensures the test efficiency.

[0009] In a preferred embodiment, the sealing module includes a first sealing ring, which is fixedly connected to the side of the test chamber close to the closing door. A second sealing ring is attached to the side of the first sealing ring away from the test chamber, and the second sealing ring is fixedly connected to the side opposite to the closing door. A first connecting seat is fixedly connected to the outside of the test chamber, and a second connecting seat is fixedly connected to the outside of the closing door. Round holes are provided in both the first connecting seat and the second connecting seat, and the same threaded rod is arranged in the round holes. A handle is fixedly connected to the side of the threaded rod away from the test chamber, and a gear is arranged on the outside of the threaded rod. The gear is movably connected to the side opposite to the second connecting seat, a locking ring is arranged on the outside of the gear, and the locking ring is slidably connected to the side opposite to the second connecting seat. A rack is fixedly connected to the inner wall of the locking ring, and the rack is engaged with the gear. A guiding buckle is slidably connected to the inner wall of the locking ring, the guiding buckle is fixedly connected to the side opposite to the second connecting seat, and a third spring is fixedly connected to the side of the guiding buckle away from the threaded rod. One end of the third spring away from the guiding buckle is fixedly connected to the inner wall of the locking ring.

[0010] By providing the sealing module, the sealing module uses the locking ring and the rack to make the device tightly fit the first sealing ring and the second sealing ring on the test chamber and the closing door during the process of screwing the threaded rod into the first connecting seat, so as to ensure that the shale sample is always kept in a sealed environment during the desorption test of the test chamber, avoid the infiltration of air in the external environment, and improve the sealing effect of the device.

[0011] A method for testing the desorption pressure of shale gas, using the above-mentioned device for testing the desorption pressure of shale gas, includes the following steps: Step 1: Grasp the handle and pull open the chamber door, use the sealing module to open the closing door, put the shale sample into the mortar, close the closing door and use the sealing module to seal it. Step 2: Close the third electric valve, open the first electric valve, start the vacuum pump, pump the air in the test chamber to vacuum, close the first electric valve, turn off the vacuum pump, and use the crushing and screening module to crush and screen the shale sample to form powder that meets the requirements. Step 3: Start the first suction pump, so that the first suction pump starts to suck the test chamber, open the third electric valve and the second electric valve, observe whether linear bubbles appear. If so, record the pressure value displayed on the control panel. When no more bubbles appear, the desorption is completed.

[0012] As can be seen from the above, the device for testing the desorption pressure of shale gas provided by the present invention has the effect that the shale sample can be fully crushed in a state of being isolated from air in the device and then screened into the required fine powder, so as to ensure the accuracy of the desorption data of the shale sample in the device. Description of the Drawings

[0013] Figure 1 It is a schematic diagram of the overall structure of a device for testing the desorption pressure of shale gas proposed by the present invention; Figure 2 Schematic cross-sectional structure diagram of a shale gas desorption pressure testing device proposed by the present invention; Figure 3 Schematic structure diagram of the crushing and screening module of a shale gas desorption pressure testing device proposed by the present invention; Figure 4 Schematic structure diagram of the mortar of a shale gas desorption pressure testing device proposed by the present invention; Figure 5 Schematic structure diagram of the accommodation frame of a shale gas desorption pressure testing device proposed by the present invention; Figure 6 Schematic structure diagram of the sealing module of a shale gas desorption pressure testing device proposed by the present invention; Figure 7 Schematic structure diagram of the locking ring of a shale gas desorption pressure testing device proposed by the present invention.

[0014] In the figure: 1, box body; 2, box door; 3, handle; 4, test box; 5, closing door; 6, control panel; 7, crushing and screening module; 701, base; 702, motor; 703, cam; 704, rotating shaft; 705, connecting rod; 706, cutting groove; 707, grinding pestle; 708, mortar; 709, fine mesh hole; 710, support frame; 711, tray; 712, platform plate; 713, first spring; 714, stabilizing frame; 715, limiting shaft; 716, accommodation frame; 717, first fitting block; 718, second fitting block; 719, arc groove; 720, connecting rod; 721, bolt; 722, second spring; 723, insertion seat; 8, sealing module; 801, first sealing ring; 802, second sealing ring; 803, first connecting seat; 804, second connecting seat; 805, threaded rod; 806, gear; 807, locking ring; 808, guiding buckle; 809, rack; 810, handle; 811, third spring; 9, exhaust pipe; 10, first electric valve; 11, physiological saline tank; 12, first conveying pipe; 13, first suction pump; 14, second conveying pipe; 15, storage tank; 16, second suction pump; 17, second electric valve; 18, third electric valve; 19, vacuum pump. Detailed implementation manners

[0015] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments.

[0016] A shale gas desorption pressure testing device disclosed by the present invention is mainly applied to scenarios where the existing desorption pressure testing device cannot crush shale samples inside the testing device.

[0017] Refer toFigure 1-7 , a shale gas desorption pressure test device, comprising a box body 1, one side of the box body 1 is connected with a box door 2 through a hinge, one side of the box door 2 away from the box body 1 is connected with a handle 3 through bolts, and the bottom inner wall of the box body 1 is connected with a test box 4 through bolts. One side of the test box 4 is connected with a closing door 5 through a hinge. A crushing and screening module 7 is arranged in the test box 4. The crushing and screening module 7 includes a motor 702. The output end of the motor 702 is connected with a cam 703 through a coupling. The outside of the cam 703 is connected with a rotating shaft 704 through bolts. The outside of the rotating shaft 704 is rotatably connected with a connecting rod 705 through a bearing. The bottom of the connecting rod 705 is rotatably connected with a grinding pestle 707 through a bearing. The outside of the grinding pestle 707 is slidably connected with a mortar 708. A plurality of fine holes 709 evenly distributed in a circumferential manner are opened on the bottom inner wall of the mortar 708. And a sealing module 8 is arranged between the test box 4 and the closing door 5.

[0018] Specifically, grasp the handle 3 to open the box door 2, use the sealing module 8 to open the closing door 5, put the shale sample into the mortar 708, close the closing door 5 and seal it with the sealing module 8. Close the electric valve three 18, open the electric valve one 10, start the vacuum pump 19, pump the air in the test box 4 to vacuum. Close the electric valve one 10, turn off the vacuum pump 19, use the crushing and screening module 7 to crush and screen the shale sample to form powder that meets the requirements. Start the suction pump one 13 to make the suction pump one 13 start to suck the test box 4. Open the electric valve three 18 and the electric valve two 17, and observe whether linear bubbles appear. If so, record the pressure value displayed on the control panel 6. When no bubbles appear anymore, the desorption is completed. The device can use the crushing and screening module 7 to fully crush the shale sample in a state of being isolated from the air in the device and then screen it into the required fine powder, so as to ensure the accuracy of the desorption data of the shale sample in the device.

[0019] Refer to Figure 3 、 Figure 4 and Figure 5, in a preferred embodiment, a base 701 is bolted to the inner wall of one side of the test chamber 4 away from the closing door 5. One side of the base 701 opposite to the motor 702 is bolted. A cutting groove 706 is formed in the upper side of the connecting rod 705. A limiting shaft 715 is slidably connected in the cutting groove 706. One side of the limiting shaft 715 opposite to the base 701 is bolted. The outer part of the mortar 708 is rotatably connected to a support frame 710 through a bearing. The bottom of the support frame 710 is bolted to a platform plate 712. A tray 711 is arranged on the inner bottom wall of the support frame 710. An exhaust pipe 9 is arranged on the upper side of the test chamber 4. An electric valve one 10 is arranged on the outer part of the exhaust pipe 9. One end of the exhaust pipe 9 away from the test chamber 4 passes through the box body 1 and is located outside the box body 1. The inner bottom wall of the box body 1 is bolted to a vacuum pump 19. The output end of the vacuum pump 19 is connected to the exhaust pipe 9 through a conduit; Six symmetric first springs 713 are bolted to the outer part of the mortar 708. One end of the first spring 713 away from the mortar 708 is bolted to the same stabilizing frame 714. The bottom of the stabilizing frame 714 is bolted to the upper side of the platform plate 712. A receiving frame 716 is slidably connected to the outer part of the platform plate 712. Symmetric first fitting blocks 717 and second fitting blocks 718 are arranged in the receiving frame 716. The bottom of the first fitting block 717 is rotatably connected to the inner bottom wall of the receiving frame 716 through a bearing. The upper side of the first fitting block 717 is in contact with the second fitting block 718. The upper side of the second fitting block 718 is bolted to the bottom of the platform plate 712. An arc-shaped groove 719 is formed in the receiving frame 716. A connecting rod 720 is slidably connected in the arc-shaped groove 719. A round hole is formed in the connecting rod 720. A pin 721 is slidably connected in the round hole. A second spring 722 is bolted to the outer part of the pin 721. One end of the second spring 722 away from the pin 721 is bolted to the outer part of the connecting rod 720; Two symmetric insertion seats 723 are bolted to the outer part of the receiving frame 716. The outer part of the pin 721 is inserted into the inner wall of one of the insertion seats 723. A fine hole is formed in the outer part of the test chamber 4. A first conveying pipe 12 is bolted in the fine hole. One end of the first conveying pipe 12 away from the test chamber 4 is provided with a physiological saline tank 11. A round opening is formed in the upper side of the physiological saline tank 11. A second conveying pipe 14 is bolted in the round opening. One end of the second conveying pipe 14 away from the physiological saline tank 11 is provided with a storage tank 15; A first suction pump 13 is arranged on the outer part of the first conveying pipe 12. The outer part of the first suction pump 13 is bolted to the outer part of the test chamber 4. The output end of the first suction pump 13 is connected to the first conveying pipe 12 through a thin pipe. A second suction pump 16 is bolted to the outer part of the test chamber 4. The output end of the second suction pump 16 is connected to the second conveying pipe 14 through a round pipe. Electric valves three 18 and electric valve two 17 are respectively arranged on the first conveying pipe 12 and the second conveying pipe 14. A control panel 6 is bolted to the side of the closing door 5 away from the test chamber 4.

[0020] Specifically, after the shale sample is placed into the mortar 708, hold the connecting rod 720 and rotate it 180 degrees in the arc-shaped groove 719. During the rotation, the fitting block one 717 connected to the connecting rod 720 uses the inclined plane to lift the fitting block two 718, so that the fitting block two 718 drives the platform plate 712 to rise in the receiving frame 716, making the mortar 708 containing the sample dock with the pestle 707. After the docking is completed, pull up the latch 721 against the elastic force of the second spring 722 to align the latch 721 with the insertion seat 723. Release the latch 721 so that the latch 721 is inserted and fixed with the insertion seat 723. Start the motor 702, and the motor 702 drives the rotating shaft 704 on the cam 703 to rotate, so that the rotating shaft 704 pushes one end of the connecting rod 705 to make a circular motion. Constrained by the limiting shaft 715 sliding in the cutting groove 706, one end of the connecting rod 705 moving with the rotating shaft 704 drives the pestle 707 to make an overall up-and-down reciprocating motion in the mortar 708, thereby grinding the shale sample in the mortar 708. The powder meeting the particle size requirements falls into the tray 711 from the fine holes 709.

[0021] In a specific application scenario, the crushing and screening module 7 is mainly applicable to the crushing and screening link in the crushing and screening process. That is, the crushing and screening module 7 can use the cam 703 and the connecting rod 705 to quickly and conveniently complete the grinding of the shale sample. By using the opened fine holes 709, the ground shale powder can be kept uniform and regular, which helps the device release shale gas during shale desorption to the greatest extent, improves the desorption effect, and ensures the test efficiency.

[0022] Refer to Figure 6 and Figure 7, in a preferred embodiment, the sealing module 8 includes a first sealing ring 801. The first sealing ring 801 is bolted to the side of the test chamber 4 close to the closing door 5. On the side of the first sealing ring 801 away from the test chamber 4, a second sealing ring 802 is attached. The second sealing ring 802 is bolted to the side opposite to the closing door 5. And a first connecting seat 803 is bolted to the outside of the test chamber 4, and a second connecting seat 804 is bolted to the outside of the closing door 5; round holes are provided in both the first connecting seat 803 and the second connecting seat 804, and the same threaded rod 805 is arranged in the round holes. And on the side of the threaded rod 805 away from the test chamber 4, a handle 810 is bolted. A gear 806 is arranged on the outside of the threaded rod 805; the gear 806 is rotatably connected to the side opposite to the second connecting seat 804 through a bearing. A locking ring 807 is arranged on the outside of the gear 806. The locking ring 807 is slidably connected to the side opposite to the second connecting seat 804. And a rack 809 is bolted to the inner wall of the locking ring 807. The rack 809 is engaged with the gear 806; a guiding buckle 808 is slidably connected to the inner wall of the locking ring 807. The guiding buckle 808 is bolted to the side opposite to the second connecting seat 804. And on the side of the guiding buckle 808 away from the threaded rod 805, a third spring 811 is bolted. One end of the third spring 811 away from the guiding buckle 808 is bolted to the inner wall of the locking ring 807.

[0023] Specifically, when closing the closing door 5, align the threaded rod 805 on the second connecting seat 804 connected to the closing door 5 with the first connecting seat 803, and push down the locking ring 807 to make the locking ring 807 move downward against the elastic force of the third spring 811, so that the rack 809 releases the locking of the gear 806. Rotate the handle 810, and the handle 810 drives the threaded rod 805 to gradually screw into the first connecting seat 803. The rotating threaded rod 805 drives the gear 806 to rotate at the same time. During the process of the threaded rod 805 screwing in, the threaded rod 805 will drive the closing door 5 to gradually press against the test chamber 4, so that the first sealing ring 801 and the second sealing ring 802 are closely attached. After the threaded rod 805 is completely screwed into the first connecting seat 803, release the locking ring 807. Under the elastic force of the third spring 811, the rack 809 and the gear 806 are re-engaged, making the threaded rod 805 unable to continue rotating.

[0024] In a specific application scenario, the sealing module 8 is mainly applicable to the sealing link during the sealing process, that is, the sealing module 8 uses the locking ring 807 and the rack 809 to make the device enable the first sealing ring 801 and the second sealing ring 802 on the test chamber 4 and the closing door 5 to be closely attached during the process of the threaded rod 805 screwing into the first connecting seat 803. Thus, when the test chamber 4 is desorbed and tested, it ensures that the shale sample always remains in a sealed environment, avoids the infiltration of air in the external environment, and improves the sealing effect of the device.

[0025] A method for testing the desorption pressure of shale gas, using a shale gas desorption pressure testing device as described above, includes the following steps: Step 1: Grasp the handle 3 to open the box door 2, use the sealing module 8 to open the closing door 5, place the shale sample into the mortar 708, close the closing door 5 and seal it with the sealing module 8 (when closing the closing door 5, align the threaded rod 805 on the connecting seat two 804 connected to the closing door 5 with the connecting seat one 803, push down the locking ring 807, so that the locking ring 807 moves downward against the elastic force of the spring three 811, release the locking of the rack 809 on the gear 806, turn the handle 810, the handle 810 drives the threaded rod 805 to gradually screw into the connecting seat one 803, the rotating threaded rod 805 drives the gear 806 to rotate at the same time. During the process of the threaded rod 805 screwing in, the threaded rod 805 drives the closing door 5 to gradually close tightly against the test box 4, so that the sealing ring one 801 and the sealing ring two 802 are closely fitted. After the threaded rod 805 is completely screwed into the connecting seat one 803, release the locking ring 807, and under the elastic force of the spring three 811, the rack 809 and the gear 806 are re-engaged, so that the threaded rod 805 cannot continue to rotate); Step 2: Close the electric valve three 18, open the electric valve one 10, start the vacuum pump 19, evacuate the air in the test box 4 to vacuum, close the electric valve one 10, close the vacuum pump 19, use the crushing and screening module 7 to crush and screen the shale sample to form powder that meets the requirements (after placing the shale sample into the mortar 708, grasp the connecting rod 720 and rotate it 180 degrees in the arc groove 719, so that the fitting block one 717 connected to the connecting rod 720 uses the inclined plane to lift the fitting block two 718 during the rotation process, so that the fitting block two 718 drives the platform plate 712 to rise in the receiving frame 716, so that the mortar 708 containing the sample is docked with the pestle 707. After the docking is completed, pull up the bolt 721 against the elastic force of the spring two 722, align the bolt 721 with the insertion seat 723, release the bolt 721, and make the bolt 721 inserted and fixed with the insertion seat 723. Start the motor 702, the motor 702 drives the rotating shaft 704 on the cam 703 to rotate, so that the rotating shaft 704 pushes one end of the connecting rod 705 to make a circular motion. Constrained by the limit shaft 715 sliding in the cut groove 706, one end of the connecting rod 705 moving with the rotating shaft 704 drives the pestle 707 to make an overall up and down reciprocating motion in the mortar 708, so as to grind the shale sample in the mortar 708, and the powder that meets the particle size requirements falls into the tray 711 from the fine pores 709); Step 3: Start the suction pump one 13, so that the suction pump one 13 starts to suction the test box 4, open the electric valve three 18 and the electric valve two 17, observe whether linear bubbles appear. If so, record the pressure value displayed on the control panel 6. When no more bubbles appear, the desorption is completed.

[0026] The above are only the preferred specific embodiments of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and inventive concept of the present invention, making equivalent substitutions or changes should be covered within the protection scope of the present invention.

Claims

1. A shale gas desorption pressure test device, comprising a box body (1), characterized in that, One side of the box body (1) is connected with a box door (2) through a hinge. A handle (3) is fixedly connected to the side of the box door (2) away from the box body (1). The inner bottom wall of the box body (1) is fixedly connected with a test box (4). One side of the test box (4) is connected with a closing door (5) through a hinge. A crushing and screening module (7) is arranged in the test box (4). The crushing and screening module (7) includes a motor (702). The output end of the motor (702) is connected with a cam (703) through a coupling. A rotating shaft (704) is fixedly connected to the outside of the cam (703). A connecting rod (705) is movably connected to the outside of the rotating shaft (704). The bottom of the connecting rod (705) is movably connected with a pestle (707). A mortar (708) is slidably connected to the outside of the pestle (707). A plurality of fine holes (709) evenly distributed at equal intervals in a circle are formed in the inner bottom wall of the mortar (708). A sealing module (8) is arranged between the test box (4) and the closing door (5).

2. The shale gas desorption pressure testing device according to claim 1, characterized in that, A base (701) is fixedly connected to the inner wall of the test box (4) on the side away from the closing door (5). The base (701) is fixedly connected to the side opposite to the motor (702). A cutting groove (706) is formed in the upper side of the connecting rod (705). A limiting shaft (715) is slidably connected in the cutting groove (706). The limiting shaft (715) is fixedly connected to the side opposite to the base (701). A support frame (710) is movably connected to the outside of the mortar (708). A platform plate (712) is fixedly connected to the bottom of the support frame (710). A tray (711) is arranged on the inner bottom wall of the support frame (710). An exhaust pipe (9) is arranged on the upper side of the test box (4). An electric valve one (10) is arranged on the outside of the exhaust pipe (9). One end of the exhaust pipe (9) away from the test box (4) passes through the box body (1) and is located outside the box body (1). A vacuum pump (19) is fixedly connected to the inner bottom wall of the box body (1). The output end of the vacuum pump (19) is connected to the exhaust pipe (9) through a conduit.

3. The shale gas desorption pressure testing device according to claim 2, characterized in that, Six symmetric first springs (713) are fixedly connected to the outside of the grinding mortar (708). One end of each first spring (713) far from the grinding mortar (708) is fixedly connected to the same stabilizing frame (714). The bottom of the stabilizing frame (714) is fixedly connected to the upper side of the platform plate (712). An accommodating frame (716) is slidably connected to the outside of the platform plate (712). Symmetric first fitting blocks (717) and second fitting blocks (718) are arranged inside the accommodating frame (716). The bottom of the first fitting block (717) is movably connected to the inner wall of the bottom of the accommodating frame (716). The upper side of the first fitting block (717) is in contact with the second fitting block (718). The upper side of the second fitting block (718) is fixedly connected to the bottom of the platform plate (712). An arc-shaped groove (719) is formed in the accommodating frame (716). A connecting rod (720) is slidably connected to the arc-shaped groove (719). A round hole is formed in the connecting rod (720). A pin (721) is slidably connected to the round hole. A second spring (722) is fixedly connected to the outside of the pin (721). One end of the second spring (722) far from the pin (721) is fixedly connected to the outside of the connecting rod (720).

4. The shale gas desorption pressure testing device according to claim 3, wherein, Two symmetric insertion seats (723) are fixedly connected to the outside of the accommodating frame (716). The outside of the pin (721) is inserted into the inner wall of one of the insertion seats (723). A fine hole is formed in the outside of the test box (4). A first conveying pipe (12) is fixedly connected to the fine hole. One end of the first conveying pipe (12) far from the test box (4) is provided with a physiological saline tank (11). A round opening is formed in the upper side of the physiological saline tank (11). A second conveying pipe (14) is fixedly connected to the round opening. One end of the second conveying pipe (14) far from the physiological saline tank (11) is provided with a storage tank (15).

5. The shale gas desorption pressure testing device according to claim 4, wherein A first suction pump (13) is arranged on the outside of the first conveying pipe (12). The outside of the first suction pump (13) is fixedly connected to the outside of the test box (4). The output end of the first suction pump (13) is connected to the first conveying pipe (12) through a thin pipe. A second suction pump (16) is fixedly connected to the outside of the test box (4). The output end of the second suction pump (16) is connected to the second conveying pipe (14) through a round pipe. An electric valve three (18) and an electric valve two (17) are respectively arranged on the first conveying pipe (12) and the second conveying pipe (14). A control panel (6) is fixedly connected to the side of the closing door (5) far from the test box (4).

6. The shale gas desorption pressure testing device according to claim 5, characterized in that, The sealing module (8) includes a first sealing ring (801). The first sealing ring (801) is fixedly connected to the side of the test box (4) close to the closing door (5). A second sealing ring (802) is in contact with one side of the first sealing ring (801) far from the test box (4). The second sealing ring (802) is fixedly connected to the side of the closing door (5) opposite thereto. A first connecting seat (803) is fixedly connected to the outside of the test box (4). A second connecting seat (804) is fixedly connected to the outside of the closing door (5).

7. The shale gas desorption pressure testing device according to claim 6, wherein, Both the first connecting seat (803) and the second connecting seat (804) are provided with round holes, and the same threaded rod (805) is arranged in the round holes. A handle (810) is fixedly connected to the side of the threaded rod (805) away from the test chamber (4), and a gear (806) is arranged outside the threaded rod (805).

8. The shale gas desorption pressure testing device according to claim 7, wherein, The side of the gear (806) opposite to the second connecting seat (804) is movably connected. A locking ring (807) is arranged outside the gear (806). The side of the locking ring (807) opposite to the second connecting seat (804) is slidably connected. A rack (809) is fixedly connected to the inner wall of the locking ring (807), and the rack (809) is engaged with the gear (806).

9. The shale gas desorption pressure testing device according to claim 8, wherein A guide buckle (808) is slidably connected to the inner wall of the locking ring (807). The guide buckle (808) is fixedly connected to the side of the second connecting seat (804) opposite thereto. A third spring (811) is fixedly connected to the side of the guide buckle (808) away from the threaded rod (805). One end of the third spring (811) away from the guide buckle (808) is fixedly connected to the inner wall of the locking ring (807).

10. A method for testing the desorption pressure of shale gas, using a shale gas desorption pressure testing device as described in claim 9, characterized in that, It includes the following steps: Step 1: Grasp the grip (3) to pull open the cabinet door (2), use the sealing module (8) to open the closing door (5), put the shale sample into the mortar (708), close the closing door (5) and use the sealing module (8) to seal it; Step 2: Close the third electric valve (18), open the first electric valve (10), start the vacuum pump (19) to pump the air in the test chamber (4) to vacuum, close the first electric valve (10), close the vacuum pump (19), and use the crushing and screening module (7) to crush and screen the shale sample to form powder that meets the requirements; Step 3: Start the first suction pump (13) to make the first suction pump (13) start to suck the test chamber (4), open the third electric valve (18) and the second electric valve (17), observe whether linear bubbles appear. If so, record the pressure value displayed on the control panel (6). When no more bubbles appear, the desorption is completed.

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