Multifunctional pump for coal-bed gas well

Abstract

The invention relates to the technical field of coal-bed gas exploitation, in particular to a coal-bed gas well multifunctional pump which comprises a multifunctional pump cylinder, a traveling valve assembly which is adjustable in height and rotatably arranged in the multifunctional pump cylinder and a fixed valve assembly arranged at the bottom end of the multifunctional pump cylinder. The top end of the multifunctional pump cylinder is connected to the multifunctional pump, and the fixed valve assembly is used for communicating the coal-bed gas well with the multifunctional pump cylinder. The traveling valve assembly comprises a hollow pull pipe, a traveling valve cover, a central spray pipe and a traveling valve. The oil pumping pipe and the hollow pull pipe are used as a high-pressure cleaning fluid manifold, and the annulus between the multifunctional pump cylinder and the hollow pull pipe is used as a cleaning fluid flowback channel, so that cleaning fluid does not enter a well, and the purpose of protecting a reservoir is achieved.

Description

Technical Field

[0001] The present invention relates to the technical field of coalbed methane mining, in particular to a multifunctional pump for coalbed methane wells. Background Art

[0002] During coalbed methane (CBM) well production, various factors, including coalbed geological conditions, production methods, and operational measures, cause changes in the coal seam and the coal rock structure near the wellbore. This results in free coal fines and debonded coal fines being transported into the wellbore with the fluid. Coal fines are typically dark gray particles with a low hardness. Clay minerals are the primary source of their formation. Under the action of associated fluids, the coal fines are easily broken down and combined with coal coke to form a viscous colloid—coal slime.

[0003] During the pumping process, some coal powder particles accumulate in the pump barrel, which causes the pump to be buried or stuck after a certain amount, resulting in frequent well shutdown, well repair, well washing and other operations, seriously affecting the high and stable production of coalbed methane wells.

[0004] When a downhole pump becomes clogged, the surface drainage and production system stops pumping and relocates the pump to clear the wellhead. A workover rig is then brought in to retrieve the downhole tubing, pump, and screen. The pump is then transported back to the plant, cleaned, unblocked, and overhauled. The downhole pump is then lowered into the tubing string and production resumes. This entire pump inspection cycle is lengthy, and prolonged downtime can severely damage the well, leading to significant production reductions after the well resumes production. Furthermore, the complex process requires significant manpower, material, and financial resources. Summary of the Invention

[0005] The present invention aims to solve at least one of the technical problems existing in the related art. To this end, the present invention provides a multifunctional coalbed methane well pump that solves the technical problem of the existing art that downhole pumps are difficult to clean in situ. The pump utilizes a pumping pipe and a hollow pull tube as a high-pressure cleaning fluid manifold, and the annulus between the multifunctional pump barrel and the hollow pull tube serves as a flowback channel for the cleaning fluid, preventing the cleaning fluid from entering the well and thus protecting the reservoir.

[0006] The present invention provides a multifunctional pump for a coalbed methane well, comprising a multifunctional pump barrel, a traveling valve assembly which is height-adjustable and rotatably disposed in the multifunctional pump barrel, and a fixed valve assembly disposed at the bottom end of the multifunctional pump barrel. The top end of the traveling valve assembly is connected to a pumping pipe, the top end of the multifunctional pump barrel is connected to an external liquid pump, and the fixed valve assembly is used to connect the coalbed methane well and the multifunctional pump barrel. The traveling valve assembly includes a hollow pull tube, a traveling valve cover, a central nozzle and a traveling valve; The top end of the hollow pull tube is connected to the oil pumping pipe. The hollow pull tube is located in the pump barrel of the multifunctional pump. A first liquid flow channel is formed inside the hollow pull tube, and a second liquid flow channel is formed between the inner wall of the pump barrel of the multifunctional pump and the outer wall of the hollow pull tube. The top of the floating valve cover is connected to the bottom of the hollow pull tube, and a first channel and a liquid cavity are formed at the center of the floating valve cover. The first channel and the liquid cavity are connected, and the central nozzle is slidably installed in the first channel. The bottom end of the floating valve cover is connected to a conversion joint, and a floating valve is provided on the top of the conversion joint. The floating valve is located in the liquid cavity, and the floating valve cover is provided with a plurality of strip holes spaced apart on the side walls corresponding to the liquid cavity, and the strip holes are used to connect the liquid cavity and the second liquid flow channel.

[0007] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that an installation cavity is opened at the central top position of the floating valve cover, the installation cavity is connected to the first channel, the inner diameter of the installation cavity is larger than the inner diameter of the first channel, a center nozzle spring is arranged in the installation cavity, the outer diameter of the center nozzle matches the inner diameter of the first channel, the top outer wall of the center nozzle forms a limiting ring, the outer diameter of the limiting ring matches the inner diameter of the installation cavity.

[0008] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that a hollow pull tube limiting section is formed at the bottom of the hollow pull tube, the floating valve cover is sleeved on the hollow pull tube, and the top of the floating valve cover abuts against the hollow pull tube limiting section.

[0009] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that the outer diameter of the floating valve hood is divided into a first valve hood section, a second valve hood section and a third valve hood section from top to bottom, the outer diameter of the first valve hood section is smaller than the outer diameter of the second valve hood section, the outer diameter of the second valve hood section is smaller than the outer diameter of the third valve hood section, the outer diameter of the third valve hood section matches the inner diameter of the multifunctional pump barrel, the outer diameter of the conversion joint matches the outer diameter of the third valve hood section, and a floating valve seat is provided on the top of the conversion joint, and the floating valve seat is used to support the floating valve.

[0010] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that the central nozzle is provided with a plurality of second through holes, the inner wall of the floating valve cover is provided with a second channel, the second through holes are used to connect the first channel and the second channel, and the bottom end of the second channel is connected to the interior of the pump barrel of the multifunctional pump.

[0011] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that a one-way valve and a fixed valve cleaning nozzle are provided at the bottom end of the second channel.

[0012] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that the fixed valve assembly includes a fixed valve cover, a fixed valve orifice plate, a central push rod and a fixed valve; The fixed valve orifice plate is connected to the bottom end of the multifunctional pump barrel, the fixed valve cover is connected to the bottom of the multifunctional pump barrel, the center push rod is fixed at the center position of the top surface of the fixed valve orifice plate, the center push rod extends in the height direction and corresponds to the floating valve, the fixed valve orifice plate is spaced apart with a plurality of third through holes, the third through holes are used to connect the multifunctional pump barrel and the fixed valve cover, the fixed valve cleaning nozzle corresponds to the position of the third through holes, the bottom end of the fixed valve cover is connected to the screen tail pipe assembly of the coalbed methane well, and the fixed valve is located in the fixed valve cover.

[0013] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that the inner side wall of the fixed valve cover is formed with a valve support portion for supporting the fixed valve.

[0014] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that a pump lower joint is inserted into the bottom of the fixed valve cover, the bottom of the pump lower joint is connected to the screen tail pipe assembly of the coalbed methane well, and a fixed valve seat is provided on the top of the pump lower joint, and the top of the fixed valve seat abuts against the valve support part.

[0015] A further improvement of the multifunctional pump for coalbed methane wells of the present invention is that the top of the hollow pull tube is inserted into the pumping pipe coupling, and the pumping pipe coupling is connected to the pumping pipe; the top of the multifunctional pump barrel is inserted into the pump upper joint, and the pump upper joint is connected to the external liquid pumping pump.

[0016] The multifunctional coalbed methane well pump of the present invention is designed to meet the normal production needs of coalbed methane wells while allowing the cleaning of both the floating and fixed valve assemblies without moving the tubing. The multifunctional coalbed methane well pump can deliver high-pressure fluid into the well, generating a high-pressure water jet for cleaning the downhole pump. This addresses current production bottlenecks encountered during coalbed methane well drainage, such as downhole pump blockage caused by coal dust settling, which necessitates downtime, tubing string removal, and surface maintenance of the downhole pump.

[0017] Additional aspects and advantages of the present invention will be set forth in part in the description which follows and, in part, will be obvious from the description which follows, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative work.

[0019] Figure 1 This is a schematic diagram of the multifunctional pump for coalbed methane wells provided by the present invention. Figure 1 .

[0020] Figure 2 This is a schematic diagram of the multifunctional pump for coalbed methane wells provided by the present invention. Figure 2 .

[0021] Figure 3 It is a schematic diagram of the valve cover of the floating valve in the multifunctional pump for coalbed methane wells provided by the present invention.

[0022] Reference numerals: 1. Pumping pipe coupling; 2. Hollow pull tube; 3. Pump upper joint; 4. Multi-function pump barrel; 5. Center nozzle spring; 6. Floating valve cover; 7. Center nozzle; 8. Floating valve; 9. Floating valve seat; 10. Adapter; 11. One-way valve; 12. Fixed valve cleaning nozzle; 13. Center push rod; 14. Guide block; 15. Fixed valve orifice plate; 16. Fixed valve cover; 17. Fixed valve; 18. Fixed valve seat; 19. Pump lower joint. DETAILED DESCRIPTION

[0023] To make the purpose, technical solutions and advantages of the present invention clearer, the technical solutions of the present invention will be clearly and completely described below in conjunction with the accompanying drawings of the present invention. Obviously, the embodiments described are part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention. The following embodiments are used to illustrate the present invention, but are not used to limit the scope of the present invention.

[0024] The following combination Figure 1 The present invention describes a multifunctional pump for a coalbed methane well, which includes a multifunctional pump barrel 4, a floating valve assembly that is height-adjustable and rotatably arranged in the multifunctional pump barrel 4, and a fixed valve assembly arranged at the bottom end of the multifunctional pump barrel 4. The top end of the floating valve assembly is connected to the oil pumping pipe, the top end of the multifunctional pump barrel 4 is connected to an external liquid pump, and the fixed valve assembly is used to connect the coalbed methane well and the multifunctional pump barrel 4.

[0025] The multifunctional coalbed methane well pump of the present invention is designed to meet the normal production needs of coalbed methane wells while allowing the cleaning of both the floating and fixed valve assemblies without moving the tubing string. The multifunctional coalbed methane well pump can deliver high-pressure fluid into the well, generating a high-pressure water jet for cleaning the downhole pump.

[0026] Furthermore, if Figure 1 、 Figure 2 and Figure 3As shown, the floating valve assembly includes a hollow pull tube 2, a floating valve cover 6, a central nozzle 7 and a floating valve 8; the top of the hollow pull tube 2 is connected to the oil pumping pipe, the hollow pull tube 2 is located in the multi-functional pump barrel 4, a first liquid flow channel is formed inside the hollow pull tube 2, and a second liquid flow channel is formed between the inner wall of the multi-functional pump barrel 4 and the outer wall of the hollow pull tube 2; the top of the floating valve cover 6 is connected to the bottom of the hollow pull tube 2, and a first channel and a liquid cavity are formed in the center position of the floating valve cover 6, the first channel and the liquid cavity are connected, the central nozzle 7 is slidably installed in the first channel, the bottom end of the floating valve cover 6 is connected to the conversion joint 10, the top of the conversion joint 10 is provided with a floating valve 8, the floating valve 8 is located in the liquid cavity, and the floating valve cover 6 is provided with a plurality of strip holes on the side wall corresponding to the liquid cavity, and the strip holes are used to connect the liquid cavity and the second liquid flow channel.

[0027] When the multifunctional pump of the coalbed methane well performs the coalbed methane extraction operation normally, the coal gas in the coalbed methane well pushes the fixed valve 17 and enters the pump barrel 4 of the multifunctional pump, and then passes through the third through hole of the fixed valve orifice plate 15, and then pushes the floating valve 8 to enter the floating valve cover 6, and then is extracted through the strip hole and the second liquid flow channel.

[0028] Furthermore, if Figure 1 、 Figure 2 and Figure 3 As shown, an installation cavity is provided at the central top position of the floating valve cover 6, and the installation cavity is connected to the first channel. The inner diameter of the installation cavity is larger than the inner diameter of the first channel. A center nozzle spring 5 is provided in the installation cavity. The outer diameter of the center nozzle 7 matches the inner diameter of the first channel. A limiting ring is formed on the top outer wall of the center nozzle 7. The outer diameter of the limiting ring matches the inner diameter of the installation cavity. The center nozzle spring 5 is used to provide a buffering force to the movement of the center nozzle 7, and the limiting ring prevents the center nozzle 7 from separating from the floating valve cover 6.

[0029] Furthermore, if Figure 1 、 Figure 2 and Figure 3 As shown, a hollow pull tube 2 limiting section is formed at the bottom position of the hollow pull tube 2, and the floating valve hood 6 is sleeved on the hollow pull tube 2. The top of the floating valve hood 6 abuts against the limiting section of the hollow pull tube 2, thereby improving the structural strength of the hollow pull tube 2. The limiting section of the hollow pull tube 2 and the floating valve hood 6 fit closely together, effectively enhancing the stability and reliability of the hollow pull tube 2 and the floating valve hood 6. In the high-intensity working environment of the multi-functional pump in the coalbed methane well, this design can prevent the floating valve hood 6 from excessive movement in the axial direction, thereby avoiding leakage problems that may be caused by loosening or displacement, and ensuring the efficient and safe operation of the pump.

[0030] Furthermore, if Figure 1 、 Figure 2 and Figure 3As shown, the outer diameter of the floating valve cover 6 is divided into a first valve cover section, a second valve cover section and a third valve cover section from top to bottom. The outer diameter of the first valve cover section is smaller than the outer diameter of the second valve cover section, and the outer diameter of the second valve cover section is smaller than the outer diameter of the third valve cover section. The outer diameter of the third valve cover section matches the inner diameter of the multi-function pump barrel 4, and the outer diameter of the conversion joint 10 matches the outer diameter of the third valve cover section. A floating valve seat 9 is provided on the top of the conversion joint 10, and the floating valve seat 9 is used to support the floating valve 8.

[0031] Preferably, the installation cavity corresponds to the first valve cover segment, the first channel corresponds to the second valve cover segment, and the liquid cavity corresponds to the third valve cover segment.

[0032] Preferably, there is a very small gap between the outer wall of the third valve cover section and the inner diameter of the multi-function pump barrel 4, and between the outer wall of the conversion joint 10 and the inner diameter of the multi-function pump barrel 4, to ensure that the third valve cover section and the conversion joint 10 can move smoothly in the multi-function pump barrel 4.

[0033] Furthermore, if Figure 1 、 Figure 2 and Figure 3 As shown, the central nozzle 7 is provided with a plurality of second through holes, and the inner wall of the floating valve cover 6 is provided with a second channel. The second through hole is used to connect the first channel and the second channel. The bottom end of the second channel is connected to the interior of the multi-functional pump barrel 4. The floating valve cover 6 is provided with an annular groove at a position corresponding to the top of the second channel to facilitate the connection between the second through hole and the second channel.

[0034] Preferably, the central channel of the central nozzle 7 is used to communicate with the first liquid flow channel and the liquid chamber.

[0035] Specifically, if Figure 1 、 Figure 2 and Figure 3 As shown, a one-way valve 11 and a fixed valve cleaning nozzle 12 are provided at the bottom end of the second channel. The fixed valve cleaning nozzle 12 can be inserted into the third through hole of the fixed valve orifice plate 15 to clean the fixed valve 17. The bottom end of the fixed valve cleaning nozzle 12 is lower than the bottom end of the floating valve cover 6.

[0036] Preferably, the fixed valve cleaning nozzle 12 is connected to the conversion joint 10 .

[0037] Furthermore, if Figure 1 、 Figure 2 and Figure 3As shown, the fixed valve assembly includes a fixed valve cover 16, a fixed valve orifice plate 15, a central push rod 13 and a fixed valve 17; the fixed valve orifice plate 15 is connected to the bottom end of the multifunctional pump barrel 4, the fixed valve cover 16 is connected to the bottom of the multifunctional pump barrel 4, the central push rod 13 is fixed to the center position of the top surface of the fixed valve orifice plate 15, the central push rod 13 extends in the height direction and corresponds to the floating valve 8, the fixed valve orifice plate 15 is spaced apart with a plurality of third through holes, the third through holes are used to connect the multifunctional pump barrel 4 and the fixed valve cover 16, the fixed valve cleaning nozzle 12 corresponds to the position of the third through hole, the bottom end of the fixed valve cover 16 is connected to the screen tail pipe assembly of the coalbed methane well, and the fixed valve 17 is located in the fixed valve cover 16.

[0038] Preferably, if Figure 1 、 Figure 2 and Figure 3 As shown, the inner side wall of the fixed valve cover 16 is formed with a valve supporting portion for supporting the fixed valve 17.

[0039] Furthermore, if Figure 1 、 Figure 2 and Figure 3 As shown, a pump lower joint 19 is inserted into the bottom of the fixed valve cover 16, and the bottom of the pump lower joint 19 is connected to the screen tail pipe assembly of the coalbed methane well. A fixed valve seat 18 is provided on the top of the pump lower joint 19, and the top of the fixed valve seat 18 abuts against the valve support part.

[0040] Furthermore, if Figure 1 、 Figure 2 and Figure 3 As shown, the top of the hollow pull tube 2 is inserted into the oil pumping pipe coupling 1, and the oil pumping pipe coupling 1 is connected to the oil pumping pipe; the top of the multifunctional pump barrel 4 is inserted into the pump upper joint 3, and the pump upper joint 3 is connected to the external liquid pumping pump.

[0041] Preferably, three second channels are provided, and three fixed valve cleaning nozzles 12 are provided; the third through hole of the fixed valve orifice plate 15 is a conical through hole, and the conical structure can be guided to facilitate the insertion of the fixed valve cleaning nozzle 12 into the third through hole; the fixed valve orifice plate 15 is evenly installed with six guide blocks 14, and the guide block 14 is located between two adjacent third through holes, and the guide block 14 is arc-shaped.

[0042] The multifunctional coalbed methane well pump of the present invention is designed to meet the normal production needs of coalbed methane wells while allowing the cleaning of both the floating and fixed valve assemblies without moving the tubing. The multifunctional coalbed methane well pump can deliver high-pressure fluid into the well, generating a high-pressure water jet for cleaning the downhole pump. This addresses current production bottlenecks encountered during coalbed methane well drainage, such as downhole pump blockage caused by coal dust settling, which necessitates downtime, tubing string removal, and surface maintenance of the downhole pump.

[0043] Example 1, as Figure 1As shown, clean the traveling valve assembly; The coalbed methane well experienced buried pumps, stuck pumps, and rod pump failures and shutdowns due to the accumulation of solid particles that buried the floating valve 8; at this time, the central nozzle 7 of the coalbed methane well multifunctional pump was in the lower position, the central nozzle 7 extended from the first channel and the bottom part was located in the liquid cavity, and the second through hole of the central nozzle 7 was closed between the second channel; the flushing power fluid on the ground entered the first liquid flow channel of the hollow pull tube 2, and then was ejected from the bottom nozzle of the central nozzle 7; the flushing power fluid carried coal powder to form a mixed liquid that returned from the strip hole of the floating valve cover 6, and the mixed liquid returned to the ground through the second liquid flow channel between the hollow pumping pipe and the multifunctional pump barrel 4, completing the cleaning of the solid particles in the floating valve seat 9 and the floating valve cover 6.

[0044] Example 2, as Figure 2 As shown, clean the fixed valve assembly; CBM wells experienced buried pumps, stuck pumps, and rod pump failures and shutdowns due to the accumulation of solid particles and the burial of fixed valves. The hollow pull tube 2 is lowered, and the fixed valve cleaning nozzle 12 moves downward. The fixed valve cleaning nozzle 12 slides down along the inclined surface of the guide block 14, causing the entire floating valve assembly and the hollow pull tube 2 to rotate. Finally, the fixed valve cleaning nozzle 12 smoothly falls into the third through hole of the fixed valve orifice plate 15; the three fixed valve cleaning nozzles 12 respectively enter the three third through holes of the fixed valve orifice plate 15, and the remaining three third through holes of the fixed valve orifice plate 15 serve as channels for cleaning return fluid; the central push rod 13 enters the holes of the conversion joint 10 and the floating valve seat 9, thereby pushing up the floating valve 8; The floating valve 8 blocks the nozzle of the central nozzle 7 and simultaneously pushes the central nozzle 7 upward to overcome the resistance of the central nozzle spring 5, causing the central nozzle 7 to move to the upper position. At this time, the bottom nozzle of the central nozzle 7 is closed, and the second channel, the central channel of the central nozzle 7, and the first liquid flow channel are connected. The ground high-pressure cleaning liquid flows from the second channel of the floating valve cover 6 through the one-way valve 11 and is sprayed out by the fixed valve cleaning nozzle 12 to clean the fixed valve 17. The cleaning return liquid for cleaning the fixed valve 17 is discharged from the fixed valve assembly through the third through hole on the fixed valve orifice plate 15 that is not blocked by the fixed valve cleaning nozzle 12. The cleaning return liquid continues to ascend, passes through the annulus of the central push rod 13, the conversion joint 10 and the floating valve seat 9, enters the liquid cavity of the floating valve valve cover 6, and then returns from the strip hole of the floating valve valve cover 6. The cleaning return liquid returns to the ground through the second liquid flow channel, completing the cleaning of the solid particles in the fixed valve assembly.

[0045] It should be pointed out finally that the above embodiments are only used to illustrate the technical solutions of the present application, but not to limit the same; and although the present application has been described in detail with reference to the foregoing embodiments, it should be appreciated by those skilled in the art that the technical solutions recorded in the foregoing embodiments can be modified, or some technical features thereof can be replaced equivalently; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present application.

Claims

1. A multifunctional pump for coalbed methane wells, characterized in that: It includes a multifunctional pump barrel, a traveling valve assembly that is height-adjustable and rotatably disposed in the multifunctional pump barrel, and a fixed valve assembly disposed at the bottom end of the multifunctional pump barrel. The top end of the traveling valve assembly is connected to a pumping pipe, and the top end of the multifunctional pump barrel is connected to an external liquid pump. The fixed valve assembly is used to connect the coalbed methane well and the multifunctional pump barrel. The traveling valve assembly includes a hollow pull tube, a traveling valve cover, a central nozzle and a traveling valve; The top end of the hollow pull tube is connected to the oil pumping pipe. The hollow pull tube is located in the pump barrel of the multifunctional pump. A first liquid flow channel is formed inside the hollow pull tube, and a second liquid flow channel is formed between the inner wall of the pump barrel of the multifunctional pump and the outer wall of the hollow pull tube. The top of the floating valve cover is connected to the bottom of the hollow pull tube, and a first channel and a liquid cavity are formed at the center of the floating valve cover. The first channel and the liquid cavity are connected, and the central nozzle is slidably installed in the first channel. The bottom end of the floating valve cover is connected to a conversion joint, and a floating valve is provided on the top of the conversion joint. The floating valve is located in the liquid cavity, and the floating valve cover is provided with a plurality of strip holes spaced apart on the side walls corresponding to the liquid cavity, and the strip holes are used to connect the liquid cavity and the second liquid flow channel.

2. The multifunctional pump for coalbed methane well according to claim 1, characterized in that: An installation cavity is provided at the central top position of the floating valve cover, and the installation cavity is connected to the first channel. The inner diameter of the installation cavity is larger than the inner diameter of the first channel. A central nozzle spring is provided in the installation cavity, and the outer diameter of the central nozzle matches the inner diameter of the first channel. A limiting ring is formed on the top outer wall of the central nozzle, and the outer diameter of the limiting ring matches the inner diameter of the installation cavity.

3. The multifunctional pump for coalbed methane well according to claim 1, characterized in that: A hollow pull tube limiting section is formed at the bottom of the hollow pull tube, the floating valve cover is sleeved on the hollow pull tube, and the top end of the floating valve cover abuts against the hollow pull tube limiting section.

4. The multifunctional pump for coalbed methane well according to claim 1, characterized in that: The outer diameter of the floating valve cover is divided into a first valve cover section, a second valve cover section and a third valve cover section from top to bottom. The outer diameter of the first valve cover section is smaller than the outer diameter of the second valve cover section, the outer diameter of the second valve cover section is smaller than the outer diameter of the third valve cover section, the outer diameter of the third valve cover section matches the inner diameter of the multi-functional pump barrel, the outer diameter of the conversion joint matches the outer diameter of the third valve cover section, and a floating valve seat is provided on the top of the conversion joint, and the floating valve seat is used to support the floating valve.

5. The multifunctional pump for coalbed methane well according to claim 1, characterized in that: The central nozzle is provided with a plurality of second through holes, and the inner wall of the floating valve cover is provided with a second channel. The second through holes are used to connect the first channel and the second channel, and the bottom end of the second channel is connected to the interior of the multi-functional pump barrel.

6. The multifunctional pump for coalbed methane well according to claim 5, characterized in that: A one-way valve and a fixed valve cleaning nozzle are provided at the bottom end of the second channel.

7. The multifunctional pump for coalbed methane well according to claim 6, characterized in that: The fixed valve assembly includes a fixed valve cover, a fixed valve orifice plate, a central push rod and a fixed valve; The fixed valve orifice plate is connected to the bottom end of the multifunctional pump barrel, the fixed valve cover is connected to the bottom of the multifunctional pump barrel, the center push rod is fixed at the center position of the top surface of the fixed valve orifice plate, the center push rod extends in the height direction and corresponds to the floating valve, the fixed valve orifice plate is spaced apart with a plurality of third through holes, the third through holes are used to connect the multifunctional pump barrel and the fixed valve cover, the fixed valve cleaning nozzle corresponds to the position of the third through holes, the bottom end of the fixed valve cover is connected to the screen tail pipe assembly of the coalbed methane well, and the fixed valve is located in the fixed valve cover.

8. The multifunctional pump for coalbed methane well according to claim 7, characterized in that: The inner side wall of the fixed valve cover is formed with a valve supporting portion for supporting the fixed valve.

9. The multifunctional pump for coalbed methane well according to claim 8, characterized in that: A pump lower joint is inserted into the bottom of the fixed valve cover, the bottom of the pump lower joint is connected to the screen tail pipe assembly of the coalbed methane well, and a fixed valve seat is set on the top of the pump lower joint, and the top of the fixed valve seat abuts against the valve support part.

10. The multifunctional pump for coalbed methane well according to claim 8, characterized in that: The top of the hollow pull tube is inserted into the oil pumping pipe coupling, and the oil pumping pipe coupling is connected to the oil pumping pipe; the top of the multifunctional pump barrel is inserted into the pump upper joint, and the pump upper joint is connected to the external liquid pumping pump.

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