A secondary fracturing device for coalbed methane wells

Abstract

This invention relates to the field of coalbed methane development technology, and more particularly to a secondary fracturing device for coalbed methane wells. This invention provides a secondary fracturing device for coalbed methane wells that can better improve gas production efficiency and clear blockages in the primary fracturing orifices. A secondary fracturing device for a coalbed methane well includes a hollow tube, circular plates, fixed plates, and arc-shaped baffles. The hollow tube is spaced apart from and connected to the delivery pipeline. Two circular plates are slidably connected to the hollow tube, and two fixed plates are fixedly connected to the hollow tube. Two arc-shaped baffles are fixed between the two fixed plates. Fracturing fluid squeezes and seals the ball, blocking it in the primary fracturing orifice on the steel casing, reducing the amount of fracturing fluid and proppant entering the primary fracturing orifice. A large amount of fracturing fluid and proppant between the two arc-shaped baffles then flows into the four secondary fracturing orifices, thereby improving the utilization rate of fracturing fluid and proppant, and thus better improving the gas production efficiency of the coalbed methane well.

Description

Technical Field

[0001] This invention relates to the field of coalbed methane development technology, and in particular to a secondary fracturing device for coalbed methane wells. Background Technology

[0002] Coal seams contain a combustible gas called coalbed methane, also known as coalbed methane. For a long time, coalbed methane has been toxic, flammable, and explosive, posing a significant threat to coal mine safety, and methane explosions have occurred frequently. Extracting coalbed methane before coal mining and scientifically and rationally developing and utilizing coalbed methane reservoirs not only helps meet the ever-increasing energy demand but also fundamentally reduces coal mine methane accidents. Fracturing technology can be used to modify coalbed methane reservoirs and improve extraction efficiency. Currently, hydraulic fracturing technology is generally used for fracturing coalbed methane wells. Hydraulic fracturing first involves perforating and fracturing the entire coal seam, followed by circulation, pressure testing, extrusion testing, fracturing, support, and pressure release. This creates a supported fracture network in the coal seam, improving permeability and allowing one or more fractures to connect to the coalbed methane well, thereby increasing the well's production. However, after prolonged gas production, the gas content within the initial fracturing perforation range decreases, leading to a significant drop in production efficiency.

[0003] Currently, after experiencing a decline in gas production efficiency in the primary fracturing orifice, some coalbed methane wells directly undergo secondary fracturing to improve gas production efficiency. However, during secondary fracturing, a significant amount of fracturing fluid is injected into the primary fracturing orifice, which contains a large amount of proppant. This proppant can block the proppant in the secondary fracturing, preventing some of the proppant from entering the fractured openings created by the secondary fracturing. Consequently, the fractured openings cannot be supported in time, and the openings close again after the secondary fracturing is completed. This results in a smaller improvement in gas production efficiency from the primary fracturing orifice. Furthermore, the primary fracturing orifice is easily blocked by impurities such as coal ash, further reducing gas production efficiency. Summary of the Invention

[0004] To address the issues of limited gas production efficiency improvement and blockage of primary fracturing orifices during secondary fracturing, this invention provides a secondary fracturing device for coalbed methane wells that can better improve gas production efficiency and clear blockages in primary fracturing orifices.

[0005] A secondary fracturing device for a coalbed methane well includes a hollow tube, circular plates, fixed plates, arc-shaped baffles, a motor mounting bracket, a drive motor, a sealing mechanism, a pushing mechanism, and a closing mechanism. The hollow tube is spaced apart from and connected to a delivery pipeline. Two circular plates are slidably connected to the hollow tube. Two fixed plates are fixedly mounted on the hollow tube, located between the two circular plates. Two arc-shaped baffles are fixedly mounted between the two fixed plates. The two arc-shaped baffles are fixedly connected. A motor mounting bracket is fixedly mounted on the upper side of the circular plate at the top of the hollow tube. The motor mounting bracket is slidably connected to the top of the hollow tube. The drive motor is fixedly mounted on the motor mounting bracket. The sealing mechanism is located on the arc-shaped baffle. The pushing mechanism is located on the arc-shaped baffle. The closing mechanism is located on the hollow tube.

[0006] Optionally, the sealing mechanism includes a short lead screw, a rotating lead screw, a guide plate frame, a push rod, a connecting rod, and a skin. Short lead screws are rotatably connected to both circular plates, and the two short lead screws are symmetrically arranged. The output shaft of the drive motor is fixedly connected to the upper short lead screw. A rotating lead screw is slidably connected between the two short lead screws. The rotating lead screw passes through two fixed plates simultaneously. Threaded brackets are fixedly connected to both fixed plates, and the threaded brackets are threadedly connected to the short lead screws. Two guide plate frames are fixedly connected to the hollow tube, and the two guide plate frames are symmetrically arranged. Several push rods are slidably connected to both guide plate frames. Several connecting rods are rotatably connected to both the circular plate and the fixed plate, and the connecting rods are rotatably connected to the push rods. A skin is fixedly connected between the circular plate and the fixed plate, and the two skins are symmetrically arranged.

[0007] Optionally, the pushing mechanism includes a rotating gear, a cam, a slotted sleeve, a pushing frame, a sliding ring, a fixed bent rod, a geared rotating column, a rope, and a sealing ball. The rotating gear is rotatably connected to the hollow tube. The slotted sleeve is fixedly connected to the rotating gear and rotatably connected to the hollow tube. The slotted sleeve is located below the rotating gear. The cam is fixedly connected to the slotted sleeve and rotatably connected to the hollow tube. The cam is located below the slotted sleeve. Several circular holes are formed on both arc-shaped baffles. Several circular holes are formed on the upper part of the arc-shaped baffles. Each of the several circular holes is slidably connected to a pusher frame, which is slidably connected to a cam. The sliding ring is threaded onto a rotating screw. The slotted sleeve has a sliding groove, and the sliding ring is slidably connected to the sliding groove on the slotted sleeve. Several fixed bent rods are fixedly connected inside the arc-shaped baffle. The geared rotating column is rotatably connected to the lower end of the fixed bent rods. The rotating gear meshes with the geared rotating column. One end of the rope is wound around the geared rotating column, and the sealing ball is fixedly connected to the other end of the rope. The sealing ball is located inside the pusher frame.

[0008] Optionally, the closing mechanism includes an annular baffle, a transmission ring, a water flow baffle, a circular perforated plate, and a guide arc plate. The annular baffle is rotatably connected to the hollow tube, and the hollow tube has several discharge holes, all located inside the annular baffle. The transmission ring is threaded to the lower part of the rotating screw and is slidably connected to the annular baffle. The water flow baffle is fixed to the lower end of the inner wall of the hollow tube. The circular perforated plate is rotatably connected to the lower end of the hollow tube, with the top of the circular perforated plate contacting the bottom of the water flow baffle. The guide arc plate is fixed to a circular plate at the bottom end of the hollow tube, and the circular perforated plate is slidably connected to the guide arc plate.

[0009] Optionally, it also includes a shaking mechanism, which is mounted on an arc-shaped baffle and connected to a rotating lead screw. The shaking mechanism includes a slotted block, a shaking frame, a return spring, and a rotating plate. Three slotted blocks are fixed to the inner wall of one of the arc-shaped baffles. The shaking frame is slidably connected between the three slotted blocks. The top of the shaking frame has four protrusions that contact the rope. A return spring is connected between the shaking frame and the slotted blocks. The rotating plate is fixed to the rotating lead screw and has several protrusions on its top. The shaking frame is located above the rotating plate.

[0010] Optionally, it also includes a support block, a limiting block, and a short rod. Several support blocks are fixedly connected to the inner wall of the skin, and several limiting blocks are fixedly connected to the fixing plate. The support blocks and limiting blocks are slidably connected, and a short rod is fixedly connected to the push rod, and the short rod contacts the limiting block.

[0011] The beneficial effects of this invention are:

[0012] 1. The operator pushes the delivery pipeline and this device into the steel casing below the ground surface. The primary fracturing orifice on the steel casing is aligned with the pusher frame. Then, the drive motor is started, and fracturing fluid and proppant are introduced into the hollow tube. The drive motor drives the short lead screw above through the output shaft, thereby causing the skin to expand outward, making the skin in close contact with the inner wall of the steel casing. The circular orifice plate and the water flow baffle will close in a staggered manner, thus blocking the fracturing fluid and proppant in the hollow tube. The pusher frame will align with the orifice on the steel casing. The fracturing fluid and proppant then flow through the discharge hole on the hollow tube to the space between the two arc-shaped baffles. Then, the fracturing fluid quickly fills the space between the two arc-shaped baffles. The fracturing fluid squeezes and seals the ball in the primary fracturing orifice on the steel casing, reducing the amount of fracturing fluid and proppant entering the primary fracturing orifice. A large amount of fracturing fluid and proppant between the two arc-shaped baffles is then discharged through the round holes on the arc-shaped baffles, and then discharged between the steel casing and the arc-shaped baffles, flowing into the four secondary fracturing orifices on the steel casing. This fracturing around the secondary fracturing orifices increases the number of fractures around the steel casing, allowing coalbed methane around the steel casing to be discharged through the secondary fracturing orifices. This allows a large amount of fracturing fluid and proppant to enter the secondary fracturing orifices, improving the utilization rate of fracturing fluid and proppant, and thus better improving the gas production efficiency of the coalbed methane well.

[0013] 2. When the screw is rotated, the vibrating frame moves up and down repeatedly. This movement causes the sealing ball to move back and forth, allowing fracturing fluid to intermittently pass through the gap between the sealing ball and the primary fracturing orifice. This flushes the inside of the primary fracturing orifice, dispersing any accumulated coal ash or other blockages and thus increasing the gas production rate of the primary fracturing orifice.

[0014] 3. When the connecting rod swings and pushes the skin to expand outward, the connecting rod drives the guide plate frame to move, the guide plate frame drives the short rod to move, and the short rod pushes the support block to fit and squeeze the inner side of the skin, so that the skin and the steel sleeve fit more fully and the seal between the skin and the steel sleeve is more complete. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the first three-dimensional structure of the present invention.

[0016] Figure 2 This is a schematic diagram of the second three-dimensional structure of the present invention.

[0017] Figure 3 This is a partial cross-sectional three-dimensional structural schematic diagram of the driving mechanism of the present invention.

[0018] Figure 4 This is a three-dimensional structural diagram of the actuating mechanism of the present invention.

[0019] Figure 5 This is a partial three-dimensional structural diagram of the sealing mechanism and the pushing mechanism of the present invention.

[0020] Figure 6 This is a schematic diagram of the first partial three-dimensional structure of the closing mechanism of the present invention.

[0021] Figure 7 For the present invention Figure 6 A magnified three-dimensional structural diagram of A in the middle.

[0022] Figure 8 For the present invention Figure 6 A magnified three-dimensional structural diagram of B.

[0023] Figure 9 This is a schematic diagram of the second partial three-dimensional structure of the closing mechanism of the present invention.

[0024] Figure 10 This is a three-dimensional structural diagram of the third part of the closing mechanism of the present invention.

[0025] Figure 11 This is a partial cross-sectional three-dimensional structural schematic diagram of the closing mechanism of the present invention.

[0026] Figure 12 This is a three-dimensional structural diagram of the water flow baffle and the circular perforated plate of the present invention.

[0027] Figure 13 This is a partial three-dimensional structural diagram of the shaking mechanism of the present invention.

[0028] Figure 14 For the present invention Figure 13 A magnified three-dimensional structural diagram of C.

[0029] Figure 15 This is a partial three-dimensional structural diagram of the driving mechanism of the present invention.

[0030] Figure 16 This is a three-dimensional structural diagram of the support block and short rod of the present invention.

[0031] The markings in the attached diagram are as follows: 1: Hollow tube, 100: Conveying pipeline, 2: Circular plate, 21: Fixed plate, 3: Arc-shaped baffle, 4: Motor mounting bracket, 5: Drive motor, 61: Short lead screw, 62: Rotating lead screw, 63: Threaded bracket, 631: Guide plate bracket, 64: Push rod, 65: Connecting rod, 66: Skin, 71: Rotating gear, 711: Slotted sleeve, 72: Cam, 73: Push bracket, 74: Sliding ring, 75: Fixed bent rod, 76: Geared rotating column, 77: Rope, 78: Sealing ball, 81: Annular baffle, 82: Transmission ring, 83: Water flow baffle, 84: Circular perforated plate, 85: Guide arc-shaped plate, 91: Slotted block, 92: Vibrating bracket, 93: Return spring, 94: Rotating plate, 101: Support block, 102: Limiting block, 103: Short rod. Detailed Implementation

[0032] All standard parts used in this invention can be purchased from the market, and irregular parts can be customized according to the description and drawings. The specific connection methods of each part adopt conventional methods such as bolts, rivets, welding, and bonding that are mature in the prior art, and will not be described in detail here.

[0033] Example 1

[0034] A secondary fracturing device for coalbed methane wells, such as Figures 1-15 As shown, the device includes a hollow tube 1, a circular plate 2, a fixing plate 21, an arc-shaped baffle 3, a motor mounting bracket 4, a drive motor 5, a sealing mechanism, a pushing mechanism, and a closing mechanism. The hollow tube 1 is spaced apart from the conveying pipeline 100 and is connected to the conveying pipeline 100. Two circular plates 2 are slidably connected to the hollow tube 1, and the two circular plates 2 are parallel. Two fixing plates 21 are welded to the hollow tube 1 and are located between the two circular plates 2. Two arc-shaped baffles 3 are bolted between the two fixing plates 21 and are fixedly connected. The motor mounting bracket 4 is riveted to the upper side of the circular plate 2 at the top of the hollow tube 1 and is slidably connected to the top of the hollow tube 1. The drive motor 5 is bolted to the motor mounting bracket 4. The sealing mechanism is located on the arc-shaped baffle 3 and is used to block the inner wall of the steel sleeve. The pushing mechanism is located on the arc-shaped baffle 3, and the closing mechanism is located on the hollow tube 1.

[0035] The sealing mechanism includes a short lead screw 61, a rotating lead screw 62, a guide plate frame 631, a push rod 64, a connecting rod 65, and a skin 66. Short lead screws 61 are rotatably connected to both circular plates 2. The short lead screws 61 are vertically arranged and symmetrically positioned. The output shaft of the drive motor 5 is fixedly connected to the upper short lead screw 61. A rotating lead screw 62 is slidably connected between the two short lead screws 61. The rotating lead screw 62 is vertically arranged and passes through both fixed plates 21. Both fixed plates 21 are welded with… A threaded bracket 63 is threadedly connected to a short lead screw 61. Two guide plate brackets 631 are bolted to the hollow tube 1. The two guide plate brackets 631 are symmetrically arranged. Several push rods 64 are slidably connected to each of the two guide plate brackets 631. Several connecting rods 65 are rotatably connected to the circular plate 2 and the fixed plate 21. The connecting rods 65 are rotatably connected to the push rods 64. A skin 66 is fixed between the circular plate 2 and the fixed plate 21. The two skins 66 are symmetrically arranged. The skin 66 is used to block the inner wall of the steel sleeve.

[0036] The pushing mechanism includes a rotating gear 71, a cam 72, a slotted sleeve 711, a pushing frame 73, a sliding ring 74, a fixed bent rod 75, a geared rotating column 76, a rope 77, and a sealing ball 78. The rotating gear 71 is rotatably connected to the hollow tube 1. The slotted sleeve 711 is welded to the rotating gear 71 and rotatably connected to the hollow tube 1. The slotted sleeve 711 is located below the rotating gear 71. The cam 72 is fixedly connected to the slotted sleeve 711 and has a guide groove. The cam 72 is rotatably connected to the hollow tube 1 and is located below the slotted sleeve 711. Both of the arc-shaped baffles 3 have several round holes. A pusher frame 73 is slidably connected to several circular holes in the upper part of the 3. The pusher frame 73 is slidably connected to the guide groove on the cam 72. The sliding ring 74 is threadedly connected to the rotating screw 62. The slotted sleeve 711 has a sliding groove. The sliding ring 74 is slidably connected to the sliding groove on the slotted sleeve 711. Several fixed bent rods 75 are welded inside the arc-shaped baffle 3. The geared rotating column 76 is rotatably connected to the lower end of the fixed bent rods 75. The rotating gear 71 meshes with the geared rotating column 76. One end of the rope 77 is wound around the geared rotating column 76. The sealing ball 78 is fixed to the other end of the rope 77. The sealing ball 78 is located inside the pusher frame 73.

[0037] The closing mechanism includes an annular baffle 81, a transmission ring 82, a water flow baffle 83, a circular perforated plate 84, and a guide arc plate 85. The annular baffle 81 is rotatably connected to the hollow tube 1, and the hollow tube 1 has several discharge holes, all located inside the annular baffle 81. The transmission ring 82 is threadedly connected to the lower part of the rotating screw 62, and the transmission ring 82 is slidably connected to the annular baffle 81. The water flow baffle 83 is welded to the lower end of the inner wall of the hollow tube 1. The circular perforated plate 84 is rotatably connected to the lower end of the hollow tube 1, and the top of the circular perforated plate 84 contacts the bottom of the water flow baffle 83. The water flow baffle 83 and the circular perforated plate 84 are used to block the fracturing fluid inside the hollow tube 1. The guide arc plate 85 is fixed to the circular plate 2 at the bottom end of the hollow tube 1, and the circular perforated plate 84 is slidably connected to the guide arc plate 85.

[0038] Initially, multiple sets of primary fracturing through-holes are drilled on the steel casing, with four through-holes in each set. When secondary fracturing is required, multiple sets of secondary fracturing through-holes are first drilled on the steel casing below the ground surface by blasting equipment, with four through-holes in each set. Then, the operator pushes the delivery pipeline 100 and this device into the steel casing below the ground surface. The through-holes of the primary fracturing on the steel casing are aligned with the pusher frame 73. There are cracks below the ground surface. Then, the worker starts the drive motor 5 and then introduces fracturing fluid and proppant into the hollow tube 1. The drive motor 5 will drive the upper short lead screw 61 to rotate through the output shaft. The upper short lead screw 61 will drive the rotating lead screw 62 and the lower short lead screw 61 to rotate. Since the short lead screw 61 is connected to the threaded frame 63 by threads, the two... When the short screw 61 rotates, it moves towards each other. The movement of the short screw 61 causes the circular plate 2 to move, which in turn causes the connecting rod 65 to swing. The swinging of the connecting rod 65 pushes the skin 66 to expand outward, making the skin 66 in close contact with the inner wall of the steel casing, thus blocking the inner wall of the steel casing. The upward movement of the circular plate 2 at the bottom of the hollow tube 1 causes the guide arc plate 85 to move upward. The guide arc plate 85 pushes the circular opening plate 84 to rotate. The circular opening plate 84 and the water flow baffle 83 are misaligned and closed. The fracturing fluid and proppant in the hollow tube 1 are blocked by the water flow baffle 83 and the circular opening plate 84. The rotation of the screw 62 causes the transmission ring 82 to move upward. The transmission ring 82 pushes the annular baffle 81 to rotate, and the annular baffle 81 no longer blocks the discharge hole on the hollow tube 1. When the lead screw 62 rotates, it causes the sliding ring 74 to move downwards. The downward movement of the sliding ring 74 causes the slotted sleeve 711, the rotating gear 71, and the cam 72 to rotate at a certain angle. The rotation of the cam 72 causes the pusher frame 73 to move away from the hollow tube 1. The pusher frame 73 will align with the hole on the steel sleeve. When the rotating gear 71 rotates, it causes the geared rotating column 76 to rotate. The rotation of the geared rotating column 76 will unwind the rope 77. The fracturing fluid and proppant will be blocked by the water flow baffle 83 and the circular perforated plate 84. The fracturing fluid and proppant will then flow through the discharge hole on the hollow tube 1 to the space between the two arc-shaped baffles 3. Then the fracturing fluid will quickly fill the space between the two arc-shaped baffles 3. The fracturing fluid squeezes and seals the ball 78, blocking it in the primary fracturing through-hole on the steel casing. This reduces the amount of fracturing fluid and proppant entering the primary fracturing through-hole. A large amount of fracturing fluid and proppant between the two arc-shaped baffles 3 are then discharged through the round holes on the arc-shaped baffles 3, and then discharged between the steel casing and the arc-shaped baffles 3. They then flow into the four secondary fracturing through-holes on the steel casing, fracturing the area around the secondary fracturing through-holes. This increases the number of fractures around the steel casing, allowing coalbed methane around the steel casing to be discharged through the secondary fracturing through-holes. This allows a large amount of fracturing fluid and proppant to enter the secondary fracturing through-holes, improving the utilization rate of fracturing fluid and proppant, and thus better improving the gas production efficiency of the coalbed methane well.After a certain amount of fracturing fluid and proppant is introduced into the hollow tube 1, the introduction is stopped, and the drive motor 5 will rotate in the opposite direction, thereby driving the short lead screw 61 and the moving lead screw to rotate in the opposite direction. The short lead screw 61 drives the two circular plates 2 to move away from each other. The circular plates 2 will drive the connecting rod 65 to swing and reset. The swing of the connecting rod 65 will push the skin 66 to retract and reset inward. The circular plate 2 at the bottom of the hollow tube 1 moves downward and resets, driving the guide arc plate 85 to move downward and reset. The guide arc plate 85 pushes the circular opening plate 84 to rotate. The water flow baffle 83 is aligned and connected with the circular opening plate 84. The water flow baffle 83 and the circular opening plate 84 no longer block the fracturing fluid and proppant in the hollow tube 1. After multiple sets of secondary fracturing through holes are fracturing, the operator pulls the delivery pipeline 100 to move the equipment out of the coalbed methane well.

[0039] Example 2

[0040] Based on Example 1, such as Figure 14 and Figure 15 As shown, it also includes a shaking mechanism, which is mounted on the arc-shaped baffle 3 and connected to the rotating screw 62. The shaking mechanism is used to move the sealing ball 78 back and forth, so that the fracturing fluid flushes the inside of the primary fracturing through hole, which can dissipate the coal ash and other blockages accumulated inside the primary fracturing through hole. The shaking mechanism includes a slotted block 91, a shaking frame 92, a return spring 93, and a rotating plate 94. Three slotted blocks 91 are welded to the inner wall of one of the arc-shaped baffles 3. The shaking frame 92 is slidably connected between the three slotted blocks 91. The top of the shaking frame 92 is provided with four protrusions. The protrusions on the top of the shaking frame 92 are in contact with the rope 77. The return spring 93 is connected between the shaking frame 92 and the slotted block 91 through a hook. The rotating plate 94 is welded to the rotating screw 62. The top of the rotating plate 94 is provided with several protrusions. The shaking frame 92 is located above the rotating plate 94.

[0041] When the lead screw 62 rotates, it drives the rotating plate 94 to rotate. The protrusion on the rotating plate 94 presses the vibrating frame 92 upward, compressing the return spring 93. The upward movement of the vibrating frame 92 pushes the rope 77 to bend. The rope 77 pulls the sealing ball 78 towards the geared rotating column 76. The rotating plate 94 continues to rotate, and the protrusion on the rotating plate 94 separates from the vibrating frame 92. The return spring 93 resets, causing the vibrating frame 92 to reset. The transmission ring 82 drives the annular baffle 81 to rotate. When the annular baffle... When 81 no longer blocks the discharge hole on the hollow tube 1, the fracturing fluid in the hollow tube 1 quickly fills the cavity between the two arc-shaped baffles 3. The fracturing fluid pushes the sealing ball 78 to block the primary fracturing through hole. Then, the shaking frame 92 squeezes the sealing ball 78 to move back and forth. When the sealing ball 78 moves back and forth, the fracturing fluid can intermittently pass through the gap between the sealing ball 78 and the primary fracturing through hole to flush the inside of the primary fracturing through hole. This can disperse the coal ash and other blockages accumulated inside the primary fracturing through hole, thereby increasing the gas production rate of the primary fracturing through hole.

[0042] Example 3

[0043] Based on Example 1, such as Figure 14 and Figure 16 As shown, it also includes a support block 101, a limiting block 102, and a short rod 103. Several support blocks 101 are welded to the inner wall of the skin 66. The support blocks 101 are used to open the skin 66. Several limiting blocks 102 are welded to the fixing plate 21. The support blocks 101 and the limiting blocks 102 are slidably connected. A short rod 103 is fixed to the push rod 64. The short rod 103 is vertically arranged and contacts the limiting block 102.

[0044] When the connecting rod 65 swings, it pushes the skin 66 to expand outward. The connecting rod 65 drives the guide plate frame 631 to move, the guide plate frame 631 drives the short rod 103 to move, and the short rod 103 pushes the support block 101 to fit and squeeze the inner side of the skin 66, so that the skin 66 fits more fully with the steel sleeve and the seal between the skin 66 and the steel sleeve is more complete.

[0045] The foregoing has shown and described the basic principles, main features, and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The embodiments and descriptions in the specification are merely illustrative of the principles of the invention. Various changes and modifications can be made to the invention without departing from its spirit and scope, and all such changes and modifications fall within the scope of the present invention as claimed. The scope of protection of this invention is defined by the appended claims and their equivalents.

Claims

1. A secondary fracturing device for a coal bed methane well, characterized by: The utility model provides a kind of sealing mechanism, including hollow pipe (1), round plate (2), fixed plate (21), arc baffle (3), motor fixing frame (4), drive motor (5), sealing mechanism, pushing mechanism and closure mechanism, the hollow pipe (1) is spaced apart with delivery pipeline (100), and hollow pipe (1) is communicated with delivery pipeline (100), two round plates (2) are slidably connected on the hollow pipe (1), two fixed plates (21) are fixedly connected on the hollow pipe (1), two fixed plates (21) are located between two round plates (2), two arc baffles (3) are fixedly connected between two fixed plates (21), two arc baffles (3) are fixedly connected, the upper side of the round plate (2) of the top end of hollow pipe (1) is fixedly connected with motor fixing frame (4), the motor fixing frame (4) is slidably connected with the top end of hollow pipe (1), the drive motor (5) is fixedly connected on motor fixing frame (4), the sealing mechanism is arranged on arc baffle (3), the pushing mechanism is arranged on arc baffle (3), and the closure mechanism is arranged on hollow pipe (1); The sealing mechanism includes short lead screw (61), rotating lead screw (62), guide plate frame (631), push rod (64), connecting rod (65) and skin (66), two round plates (2) are rotatably connected with short lead screw (61), two short lead screws (61) are symmetrically arranged, the output shaft of drive motor (5) is fixedly connected with upper short lead screw (61), rotating lead screw (62) is slidably connected between two short lead screws (61), rotating lead screw (62) passes through two fixed plates (21) simultaneously, two fixed plates (21) are fixedly connected with screw frame (63), screw frame (63) is connected with short lead screw (61) by screw thread, two guide plate frames (631) are fixedly connected on hollow pipe (1), two guide plate frames (631) are symmetrically arranged, a plurality of push rods (64) are slidably connected on two guide plate frames (631), a plurality of connecting rods (65) are rotatably connected on round plate (2) and fixed plate (21), connecting rod (65) is rotatably connected with push rod (64), skin (66) is fixedly connected between round plate (2) and fixed plate (21), two skins (66) are symmetrically arranged; The pushing mechanism comprises a rotating gear (71), a cam (72), a slotted sleeve (711), a pushing frame (73), a sliding ring (74), a fixed bent rod (75), a geared rotating column (76), a rope (77) and a sealing ball (78), the rotating gear (71) is rotatably connected to the hollow pipe (1), the slotted sleeve (711) is fixedly connected to the rotating gear (71) and rotatably connected to the hollow pipe (1), the slotted sleeve (711) is located below the rotating gear (71), the cam (72) is fixedly connected to the slotted sleeve (711), the cam (72) is rotatably connected to the hollow pipe (1), the cam (72) is located below the slotted sleeve (711), a plurality of round holes are formed in the two arc-shaped baffles (3), the pushing frame (73) is slidably connected to the plurality of round holes in the upper portion of the arc-shaped baffle (3), the pushing frame (73) is slidably connected to the cam (72), the sliding ring (74) is threadedly connected to the rotating lead screw (62), a sliding groove is formed in the slotted sleeve (711), the sliding ring (74) is slidably connected to the sliding groove in the slotted sleeve (711), a plurality of fixed bent rods (75) are fixedly connected to the arc-shaped baffle (3), the geared rotating column (76) is rotatably connected to the lower end of the fixed bent rod (75), the rotating gear (71) is engaged with the geared rotating column (76), one end of the rope (77) is wound around the geared rotating column (76), the sealing ball (78) is fixedly connected to the other end of the rope (77), and the sealing ball (78) is located in the pushing frame (73).

2. The device according to claim 1, characterized in that: The closing mechanism comprises an annular baffle (81), a transmission ring (82), a water flow baffle (83), a circular perforated plate (84) and a guide arc-shaped plate (85), the annular baffle (81) is rotatably connected to the hollow pipe (1), a plurality of discharge holes are formed in the hollow pipe (1) and located on the inner side of the annular baffle (81), the transmission ring (82) is threadedly connected to the lower portion of the rotating lead screw (62), the transmission ring (82) is slidably connected to the annular baffle (81), the water flow baffle (83) is fixedly connected to the lower end of the inner wall of the hollow pipe (1), the circular perforated plate (84) is rotatably connected to the lower end of the hollow pipe (1), the top of the circular perforated plate (84) is in contact with the bottom of the water flow baffle (83), and the guide arc-shaped plate (85) is fixedly connected to the circular plate (2) at the bottom end of the hollow pipe (1), the circular perforated plate (84) is slidably connected to the guide arc-shaped plate (85).

3. The device according to claim 2, characterized in that: Also include the jitter mechanism, the jitter mechanism is located on the arc baffle (3) and is connected with the rotating screw (62), the jitter mechanism includes a slotted block (91), a jitter frame (92), a reset spring (93) and a rotating plate (94), wherein one of the arc baffle (3) inner wall is fixedly connected with three slotted blocks (91), three slotted blocks (91) are slidably connected with the jitter frame (92), the top of the jitter frame (92) is provided with four lugs, the lugs on the top of the jitter frame (92) are in contact with the cable (77), the reset spring (93) is connected between the jitter frame (92) and the slotted block (91), the rotating plate (94) is fixedly connected on the rotating screw (62), the top of the rotating plate (94) is provided with a plurality of convex points, and the jitter frame (92) is located above the rotating plate (94).

4. The device according to claim 3, characterized in that: Also include a support block (101), a limiting block (102) and a short rod (103), a plurality of support blocks (101) are fixedly connected on the inner wall of the skin (66), a plurality of limiting blocks (102) are fixedly connected on the fixed plate (21), the support block (101) is slidably connected with the limiting block (102), the short rod (103) is fixedly connected on the push rod (64), and the short rod (103) is in contact with the limiting block (102).

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