Coal bed gas horizontal well spiral conveying type sand bailing method and device

Abstract

The invention provides a coal bed gas horizontal well spiral conveying type sand bailing method and device, sand bailing is carried out through a spiral conveyor, the spiral conveyor is connected with a screw motor, the screw motor provides power, and the screw motor is circularly driven through a driving medium. Pressure potential energy of a driving medium is converted into kinetic energy enabling the motor to rotate through the screw motor, power is provided for the screw conveyor through the screw motor, dragging force generated by rotation of the screw conveyor is used for replacing suction force in a traditional sand bailing pump method, the single-time sand bailing amount and the shaft cleaning efficiency can be improved, and the labor intensity of workers is lowered. Therefore, the continuous production time of a single well is prolonged, the operation cost caused by frequent pump inspection is reduced, and safeguard measures are provided for stable drainage and mining of coal bed gas.

Description

Technical Field

[0001] The invention relates to the technical field of coalbed methane development, and in particular to a method and device for spiral conveying sand bailing in a coalbed methane horizontal well. Background Art

[0002] During the drainage process of coalbed methane wells after fracturing, formation sand, fracturing sand, and coal dust will enter the wellbore with the formation fluid, causing wellbore blockage, drainage pump wear, pump jam, etc., and resulting in a decrease in gas production. Most of the hydraulic sand flushing methods are now used. With the help of high-speed circulating liquid, the sand and powder accumulated in the wellbore can be dispersed and carried to the ground. However, due to the low reservoir pressure after drainage, the water loss during the well washing process is serious, the liquid flow rate in the wellbore is low, and an effective circulation cannot be established. It is difficult to return sand and coal dust to the wellbore. On the contrary, the injection of water will also bring the following four adverse effects to coalbed methane drainage: first, it causes the formation pressure to rise, so that methane is re-adsorbed in the coal seam; second, it causes the Jiamin effect; third, it causes the speed-sensitive effect; fourth, it presses coal dust into the reservoir, causing reservoir fracture pollution and reduced production. The above four reasons will reduce the coalbed methane production of coalbed methane wells after the resumption of drainage.

[0003] The Chinese invention patent document with publication number CN111101897A discloses a method, device and application of drilling and grinding wells with a continuous tubing screw drill. The principle is to use a three-cone drill bit to circulate guar gum base liquid into the well during drilling and grinding, enhance the carrying capacity, and finally effectively wash out the mud in the well. If this method is used for sand bailing in coalbed methane horizontal wells, there are the following problems: the sand bailing process of this method requires the establishment of an effective circulation in the wellbore, but in a coalbed methane wellbore with serious formation leakage, an effective circulation cannot be established, and it will cause irreversible damage to coalbed methane wells that have entered the drainage stage for a long time.

[0004] The Chinese invention patent document with publication number CN219795196U discloses a negative pressure sand bailing pump for the entire horizontal well section of an underpressure coalbed methane reservoir, and the Chinese invention patent document with publication number CN202300321U discloses a horizontal well sand bailing device. The principle of these two patents is to drive the piston pump in the well to generate negative pressure suction by pulling the oil pipe up and down, and to suck solid impurities such as coal powder and fracturing sand from the front sand shovel position into the sand settling tube with an annular baffle. After the sand settling tube is filled, the oil pipe is lifted to remove the coal powder and fracturing sand in the sand settling tube. The above two patents have the following two problems: First, the power for coal powder and fracturing sand to enter the sand settling tube only comes from the suction effect brought by the piston, and the size of the suction force is limited by the pulling speed and the cross-sectional size of the suction piston. Secondly, when a large amount of coal powder and fracturing sand enter the sand settling tube, it will increase the resistance and further reduce the suction force, so it is impossible to effectively scoop up the coal powder and fracturing sand in the well. Secondly, due to the limitation of the shape and working principle of the front-end sand shovel, it is unable to effectively remove large particles of gravel and bridge plug fragments in the wellbore.

[0005] The Chinese invention patent document with publication number CN115822530A discloses an integrated tool and method for perforating with a long horizontal section of pressurized drill pipe transmission and well flushing. Its essence is to provide a method for combining fracturing and well flushing. It is mainly used in the fracturing process and cannot be applied to the coalbed methane production process. Summary of the invention

[0006] The technical problem to be solved by the present invention is how to effectively dredge sand and improve the efficiency of dredging sand.

[0007] The present invention solves the above technical problems through the following technical means:

[0008] The first aspect of the present invention provides a method for spiral conveying sand dredging in a coalbed methane horizontal well, comprising the following steps: dredging sand by a spiral conveyor, wherein the spiral conveyor is connected to a screw motor, the screw motor provides power, and the screw motor is circulated and driven by a driving medium.

[0009] Beneficial effects: The present invention converts the pressure potential energy of the driving medium into kinetic energy for rotating the motor through a screw motor, provides power to the screw conveyor through the screw motor, and uses the drag force generated by the rotation of the screw conveyor to replace the suction force in the traditional sand bailing pump method, which can increase the single sand bailing amount and wellbore cleaning efficiency, thereby extending the continuous production time of a single well, reducing the operating costs caused by frequent pump inspections, and providing safeguards for the smooth drainage of coalbed methane.

[0010] Preferably, sand is bailed out by a screw conveyor, and the reservoir fluid in the sand bailing process can be circulated in the horizontal well, and the circulation of the reservoir fluid and the circulation of the driving medium are independent of each other.

[0011] Beneficial effect: Since the reservoir fluid circulation and the driving medium circulation of the present invention are independent of each other, it is possible to perform non-overpressure and efficient sand bailing work on coalbed methane horizontal wells in the drainage stage, solving the problem that positive and reverse circulation well washing cannot be used in reservoirs with severe formation leakage and that sufficient suction force cannot be provided when using a negative pressure sand bailing pump.

[0012] The second aspect of the present invention provides a spiral conveying sand bailing device for coalbed methane horizontal wells, which applies the above-mentioned spiral conveying sand bailing method for coalbed methane horizontal wells, including arranging a power oil pipe in the wellbore, one end of the power oil pipe is connected to the dual-channel screw motor, the sand storage chamber, the screw conveyor and the sand bailing shovel in sequence; a high-pressure inner tube is provided inside the power oil pipe, and the high-pressure inner tube is connected to the dual-channel screw motor. The conveying pipe conveys a medium that can drive the dual-channel screw motor to rotate, and is connected to the high-pressure inner tube. The medium then returns through the annulus between the power oil pipe and the high-pressure inner tube.

[0013] Beneficial effect: The sand bailing device of the present invention circulates the dual-channel screw motor driving medium internally through the annulus between the conveying pipe, the high-pressure inner pipe, the power oil pipe and the high-pressure inner pipe, thereby providing power to realize the rotation of the dual-channel screw motor.

[0014] Preferably, the sand storage chamber is provided with a buffer chamber, the sand storage chamber is separated from the sand storage chamber by a sand isolation plate, the sand isolation plate is provided with a filtrate hole, the buffer chamber is provided with a liquid outlet hole on its circumference, and the liquid outlet hole is inclined toward the dual-channel screw motor.

[0015] Beneficial effect: The sand bailing device of the present invention conveys the mixture of sand, coal powder and reservoir fluid to the sand storage chamber through a sand bailing shovel and a screw conveyor. The sand barrier plate can prevent the sand and coal powder from passing through, but allow the reservoir fluid to pass through. The reservoir fluid enters the buffer chamber through the sand barrier plate, and then flows into the annulus between the power oil pipe and the wellbore through the liquid outlet hole of the buffer chamber, and returns to the working face of the sand bailing shovel, thereby realizing the external circulation of the reservoir fluid. Meanwhile, the internal circulation and the external circulation are independent of each other, and non-overpressure and efficient sand bailing can be performed on coalbed methane horizontal wells in the drainage stage, thereby solving the problem that positive and reverse circulation well washing cannot be used in reservoirs with serious formation leakage, and sufficient suction force cannot be provided when using a negative pressure sand bailing pump.

[0016] Preferably, the dual-channel screw motor includes a channel and a screw motor, the channel includes a drive channel and a return channel, the drive channel is connected to the delivery pipe, the return channel is connected to the power oil pipe, the end of the drive channel is provided with a liquid outlet that can flow the medium into the return channel, and a screw motor is provided inside the drive channel.

[0017] Preferably, the dual-channel screw motor is connected to the sand storage chamber via a buffer chamber, a transmission shaft is provided inside the sand storage chamber, the transmission shaft is connected to the screw motor of the dual-channel screw motor, and the connection is sealed using a sealing filler.

[0018] Preferably, the transmission shaft is provided with a first spiral plate, the length of which is 0.1 to 0.15 times the inner diameter of the sand storage chamber; the transmission shaft is provided with a support rod, the support rod is connected to a bearing, the bearing sleeve is arranged in the transmission shaft, and a plurality of bearing balls are arranged in the middle thereof.

[0019] Preferably, a sand retaining plate is arranged on the circumference of the sand storage chamber, the angle between the sand retaining plate and the surface of the sand storage chamber is 40° to 60°, and the height thereof is 0.25 to 0.3 times the inner diameter of the sand storage chamber.

[0020] Preferably, the transmission shaft is longer than the length of the sand storage chamber and passes through the sand storage chamber, and is arranged inside the screw conveyor. The transmission shaft is provided with a second spiral plate inside the screw conveyor, and the height of the second spiral plate is the same as the inner diameter of the screw conveyor.

[0021] Preferably, the medium flows into a storage tank through the annulus between the power oil pipe and the high-pressure inner pipe. The storage tank is arranged on the ground, the delivery pipe is connected to the storage tank, and the medium is high-pressure water or compressed air. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 This is an implementation state diagram of a double-circulation spiral conveying sand bailing device for a coalbed methane horizontal well in an embodiment;

[0023] Figure 2 Schematic diagram of the structure of a double-circulation spiral conveying sand bailing device for a coalbed methane horizontal well in an embodiment;

[0024] Figure 3 It is an enlarged view of point A in the embodiment;

[0025] Figure 4 is a cross-sectional view taken along line aa in the embodiment;

[0026] Figure 5 is a cross-sectional view taken at point bb in the embodiment;

[0027] In the figure: 1-wellbore; 2-operating room; 3-reel; 4-wire; 5-pulley block; 6-down pipe head; 7-conveying pipe; 8-return liquid port; 9-high-pressure inner pipe; 10-power oil pipe; 11-centralizer; 20-dual-channel screw motor; 211-driving flow channel; 212-return channel; 22-stator; 23-rotor; 24-liquid outlet; 30-sand storage chamber; 31-sand retaining plate; 32-drive shaft; 321-bearing ball; 322-bearing; 323-support rod; 33-first spiral plate; 34-buffer chamber; 341-liquid outlet; 35-sand isolation plate; 351-filtrate hole; 36-sand inlet channel; 40-screw conveyor; 42-second spiral plate; 50-sand shovel; 60-sand coal powder. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution in the embodiments of the present invention will be clearly and completely described in combination with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0029] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention; in addition, the terms "first", "second", and "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. It should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be a connection between the two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0030] according to Figure 1-5 As shown, this embodiment provides a spiral conveying sand bailing device for coalbed methane horizontal wells, and applies a spiral conveying sand bailing method for coalbed methane horizontal wells, including arranging a power oil pipe 10 in a wellbore 1, one end of the power oil pipe 10 is connected to a dual-channel screw motor 20, a sand storage chamber 30, a screw conveyor 40 and a sand bailing shovel 50 in sequence, and the other end of the power oil pipe 10 is connected to a storage tank on the ground (not shown), and a high-pressure inner tube 9 is provided inside the power oil pipe 10, and the aperture of the high-pressure inner tube 9 is smaller than the power oil pipe 10, one end of the high-pressure inner tube 9 is also connected to the dual-channel screw motor 20, and the other end is connected to the storage tank through a delivery pipe 7, and the delivery pipe 7 delivers high-pressure water, and the high-pressure water returns to the storage tank through the annulus between the power oil pipe and the high-pressure inner tube.

[0031] In this embodiment, the high-pressure water that drives the dual-channel screw motor 20 to rotate is circulated internally through the conveying pipe 7, the high-pressure inner pipe 9, the power oil pipe 10 and the annulus of the high-pressure inner pipe 9, thereby driving the dual-channel screw motor 20 to rotate, and the rotation of the dual-channel screw motor 20 provides power to the sand storage chamber 30 and the screw conveyor 40.

[0032] A plurality of stabilizers 11 are provided on the outside of the power oil pipe 10. In the present embodiment, a stabilizer 11 is provided at intervals of 100 m on the power oil pipe 10, so that the power oil pipe 10 is located in the middle of the wellbore 1. This can not only reduce the collision damage of the power oil pipe 10 to the wall of the wellbore 1, but also reduce the friction resistance of the power oil pipe 10 in the wellbore 1.

[0033] The dual-channel screw motor 20 includes a channel and a screw motor. The channel is connected to the high-pressure inner tube 9 and the power oil pipe 10. The channel is provided with a driving channel 211 and a return channel 212. The driving channel 211 is connected to the high-pressure inner tube 9. The screw motor is arranged inside the driving channel 211. The screw motor includes a stator 22 and a rotor 23. The stator 22 is fixed on the rotor 23. The high-pressure water drives the rotor 23 to rotate in the stator 22 through the driving channel 211, thereby driving the screw motor to rotate, thereby achieving the purpose of driving the dual-channel screw motor 20 to rotate by high-pressure water.

[0034] A liquid outlet 24 is provided at the end of the driving channel 211, and the screw motor is connected to the sand storage chamber 30 through the liquid outlet 24, and a sealing filler is used to seal the connection, so that the high-pressure water cannot flow into the sand storage chamber 30, but flows into the return channel 212 of the dual-channel screw motor 20 through both sides of the liquid outlet 24, and finally flows into the storage tank through the annulus between the power oil pipe 10 and the high-pressure inner tube 9. Therefore, the direction of high-pressure water outflow is exactly opposite to the direction of flow in. The high-pressure water is pressurized by the high-pressure pump and transported to the delivery pipe 7, and then transported to the dual-channel screw motor 20 through the high-pressure inner tube 9, so that the high-pressure water circulates internally to drive the dual-channel screw motor 20 to rotate.

[0035] The length of the sand storage chamber 30 is set according to the length of the coalbed methane horizontal well and the amount of sand returned from the reservoir. The sand storage capacity of the sand storage chamber 30 is positively correlated with the length of the sand storage chamber. The length of the sand storage chamber 30 is generally 100-500m, and the sand storage capacity is 200-1000L. The sand storage chamber 30 of this embodiment is cylindrical in shape, 300m in length, and has a sand storage capacity of 60000L.

[0036] A transmission shaft 32 is provided in the center of the sand storage chamber 30, and the transmission shaft 32 is connected to the screw motor of the dual-channel screw motor 20, and the transmission shaft 32 is driven to rotate by the screw motor. A first spiral plate 33 is provided on the circumference of the transmission shaft 32, and the height of the first spiral plate 33 is 0.1 times the inner diameter of the sand storage chamber 30, so that the sand and coal powder 60 entering the sand storage chamber 30 can be transported to the deep part of the sand storage chamber 30 without blocking the entrance and affecting the subsequent sand feeding. The sand and coal powder 60 refers to fracturing sand and coal powder.

[0037] The transmission shaft 32 is provided with a support rod 323, one end of the support rod 323 is connected to the bearing 322, and the other end is connected to the inner wall of the sand storage chamber 30. The bearing 322 is sleeved in the transmission shaft 32, and a plurality of bearing balls 321 are arranged in the middle. In this embodiment, three support rods 323 are provided to support the transmission shaft 32, and the angle between adjacent support rods 323 is 120°, which can keep the transmission shaft 32 in the middle of the sand storage chamber 30, thereby maintaining the efficient transmission of the transmission shaft 32. The adjacent support rods 323 and the inner wall of the sand storage chamber 30 form a sand inlet channel 36, so that the sand coal powder 60 and the reservoir fluid transported by the screw conveyor 40 and the sand shovel 50 are transported to the deep of the sand storage chamber 30 through the sand inlet channel 36.

[0038] A sand baffle 31 is provided on the inner circumference of the sand storage chamber 30, and the sand baffle 31 is inclined toward the dual-channel screw motor 20, so that the sand baffle 31 and the surface of the sand storage chamber 30 have an angle, and the angle is 40°~60°. The angle in this embodiment is 45°. The height of the sand baffle 31 is 0.25 times the inner diameter of the sand storage chamber 30. The purpose of setting the sand baffle 31 is to accelerate the sedimentation of the sand and coal powder 60; so that the sand and coal powder 60 can be gradually filled into the depth of the sand storage chamber 30; after the sand bailing operation is completed, the sand and coal powder 60 inside the sand storage chamber 18 is prevented from falling by lifting the power oil pipe 10.

[0039] A buffer chamber 34 is provided at the front end of the sand storage chamber 30, and the buffer chamber 34 is connected to the dual-channel screw motor 20. The transmission shaft 32 passes through the buffer chamber 34. The buffer chamber 34 is separated from the sand storage chamber 30 by a sand isolation plate 35. The surface of the sand isolation plate 35 is provided with uniform filtrate holes 351. The buffer chamber 34 is provided with liquid outlet holes 341 on its circumference. The liquid outlet holes 341 are inclined toward the dual-channel screw motor 20, and the liquid outlet holes 341 and the buffer chamber 34 form an angle of 60°. The buffer chamber 34 is provided in this embodiment in order to realize the external circulation of the reservoir fluid between the buffer chamber 34 and the bottom of the wellbore 1, thereby increasing the sand bailing intensity and efficiency; the specific external circulation process is as follows: the sand coal powder 60 is blocked in the sand storage chamber 30, and the reservoir fluid enters the buffer chamber 34 through the filtrate hole 351, and then enters the annulus between the wellbore 1 and the sand storage chamber 30 through the liquid outlet hole 341 of the buffer chamber 34, flows into the working surface of the sand bailing shovel 50 through the annulus, and is once again transported to the sand storage chamber 30 through the sand bailing shovel 50 and the screw conveyor 40, and flows into the annulus between the wellbore 1 and the sand storage chamber 30 through the buffer chamber 34, thereby realizing the external circulation of the reservoir fluid.

[0040] The screw conveyor 40 is connected to the sand storage chamber 30. The transmission shaft 32 is longer than the length of the sand storage chamber 30 and passes through the sand storage chamber 30. It is arranged inside the screw conveyor 40. The transmission shaft 32 is provided with a second spiral plate 42 inside the screw conveyor 40. The height of the second spiral plate 42 is the same as the inner diameter of the screw conveyor 40. The sand coal powder 60 and the reservoir fluid are rotated and transported to the sand storage chamber 30 through the second spiral plate 42. The motor of the dual-channel screw motor 20 drives the screw to rotate, thereby driving the transmission shaft 32 to rotate, driving the second spiral plate 42 to rotate, and the rotation of the second spiral plate 42 drives the sand coal powder 60 and the reservoir fluid to enter the screw conveyor 40 and the sand storage chamber 30 in turn.

[0041] The screw conveyor 40 is connected to the sand scoop 50, and the transmission shaft 32 is connected to the sand scoop 50. The sand scoop 50 is driven to rotate by the transmission shaft 32, so that the sand scoop 50 can scoop sand, so that the sand and coal powder 60 and the reservoir fluid enter the inside of the screw conveyor 40, and then the second spiral plate 42 rotates to drive the sand and coal powder 60 and the reservoir fluid into the sand storage chamber 30. The reservoir fluid further enters the buffer chamber 34, and then enters the annulus between the wellbore 1 and the sand storage chamber 30 from the liquid outlet 341 of the buffer chamber 34, and flows into the working surface of the sand scoop 50 through the annulus to achieve external circulation of the reservoir fluid.

[0042] The working principle of the double-circulation spiral conveying sand bailing device for coalbed methane horizontal wells in this embodiment is as follows:

[0043] like Figure 1 As shown, the power oil pipe 10 and the high-pressure inner pipe 9 of this embodiment are extended into the wellbore 1 through the downtube head 6, the high-pressure inner pipe 9 is connected to the delivery pipe 7, the delivery pipe 7 is connected to the storage tank, and the dual-channel screw motor is driven to rotate by delivering high-pressure water. The high-pressure water enters the storage tank through the return liquid port 8 of the power oil pipe 10 after being filtered, and then is delivered to the delivery pipe 7 after being pressurized by the high-pressure pump, and then is delivered to the dual-channel screw motor 20 through the high-pressure inner pipe 9, so as to realize the internal circulation of high-pressure water and achieve the purpose of driving the dual-channel screw motor 20; the downtube head 6 is connected to the reel 3 by the steel wire 4 through the pulley group 5 just above, and the power oil pipe 10 is lifted or lowered by changing the rotation direction of the reel 3 through the operating room 2.

[0044] like Figure 2As shown, the dual-channel screw motor 20 is driven by high-pressure water to rotate, and the motor drives the screw to rotate, which is connected to the transmission shaft 32 through the screw, and drives the transmission shaft 32 to rotate, and the sand coal powder 60 and the reservoir fluid are transported to the sand storage chamber 30 through the sand shovel 50 and the second spiral plate 42. The reservoir fluid flows into the buffer chamber 34 through the filtrate hole 351 of the sand isolation plate 35, and then flows into the annulus between the wellbore 1 and the sand storage chamber 30 through the liquid outlet hole 341, and flows into the working surface of the sand shovel 50 through the annulus, so as to realize the external circulation of the reservoir fluid and improve the sand bailing strength and efficiency.

[0045] In summary, the dual-channel spiral conveying sand bailing method and device for coalbed methane horizontal wells disclosed in the present invention not only solves the problem that it is impossible to use the forward and reverse circulation well washing method to bailed sand in the initial sand bailing of coalbed methane wells with serious formation leakage, but also overcomes the problem that the pull-out piston pump cannot provide strong suction force and cannot effectively bailed sand. It can increase the amount of sand bailed in a single time and improve the wellbore cleaning capacity, thereby extending the continuous production time of a single well, reducing operating costs, and providing guarantee measures for the smooth drainage and production of coalbed methane.

[0046] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A spiral conveying sand dredging method for coalbed methane horizontal wells, characterized in that: The following steps are involved: Sand is scooped by a screw conveyor (40), wherein the screw conveyor (40) is connected to a screw motor and powered by the screw motor, and the screw motor is driven cyclically by a driving medium.

2. The spiral conveying sand bailing method for coalbed methane horizontal well according to claim 1, characterized in that: Sand is bailed out by means of a screw conveyor (40), and during the sand bailing process, the reservoir fluid can circulate in the horizontal well, and the circulation of the reservoir fluid and the circulation of the driving medium are independent of each other.

3. A spiral conveying sand bailing device for coalbed methane horizontal well, characterized in that: The method for spiral conveying sand bailing in coalbed methane horizontal wells according to claim 1 or 2 comprises: arranging a power oil pipe (10) in the wellbore (1), one end of the power oil pipe (10) being connected to a dual-channel screw motor (20), a sand storage chamber (30), a screw conveyor (40) and a sand bailing shovel (50) in sequence; a high-pressure inner tube (9) is arranged inside the power oil pipe (10), the high-pressure inner tube (9) is connected to the dual-channel screw motor (20), a conveying pipe (7) conveys a medium capable of driving the dual-channel screw motor (20) to rotate, and is connected to the high-pressure inner tube (9), and the medium is then returned through the annulus between the power oil pipe (10) and the high-pressure inner tube (9).

4. The spiral conveying sand bailing device for coalbed methane horizontal well according to claim 3 is characterized in that: The sand storage chamber (30) is provided with a buffer chamber (34), the sand storage chamber (30) is separated from the sand storage chamber (30) by a sand isolation plate (35), the sand isolation plate (35) is provided with a filtrate hole (351), and the buffer chamber (34) is provided with a liquid outlet hole (341) on its circumference, and the liquid outlet hole (341) is inclined toward the dual-channel screw motor (20).

5. The spiral conveying sand bailing device for coalbed methane horizontal well according to claim 3 is characterized in that: The dual-channel screw motor (20) comprises a channel and a screw motor, wherein the channel comprises a drive channel (211) and a return channel (212), wherein the drive channel (211) is connected to a delivery pipe (7), and the return channel (212) is connected to a power oil pipe (10), wherein a liquid outlet (24) capable of allowing a medium to flow into the return channel (212) is provided at the end of the drive channel (211), and wherein a screw motor is provided inside the drive channel (211).

6. The spiral conveying sand bailing device for coalbed methane horizontal well according to claim 5, characterized in that: The dual-channel screw motor (20) is connected to the sand storage chamber (30) via a buffer chamber (34); a transmission shaft (32) is provided inside the sand storage chamber (30); the transmission shaft (32) is connected to the screw motor of the dual-channel screw motor (20); and the connection is sealed using a sealing filler.

7. The spiral conveying sand bailing device for coalbed methane horizontal well according to claim 6, characterized in that: The transmission shaft (32) is provided with a first spiral plate (33), the length of which is 0.1 to 0.15 times the inner diameter of the sand storage chamber (30); the transmission shaft (32) is provided with a support rod (323), the support rod (323) is connected to a bearing (322), the bearing (322) is sleeved in the transmission shaft (32), and a plurality of bearing balls (321) are arranged in the middle of the bearing.

8. The spiral conveying sand bailing device for coalbed methane horizontal wells according to claim 6, characterized in that: A sand retaining plate (31) is arranged on the circumference of the sand storage chamber (30), the angle between the sand retaining plate (31) and the surface of the sand storage chamber (30) is 40° to 60°, and the height thereof is 0.25 to 0.3 times the inner diameter of the sand storage chamber (30).

9. The double-circulation screw conveying sand bailing device for coalbed methane horizontal well according to claim 6, characterized in that: The transmission shaft (32) is longer than the length of the sand storage chamber (30) and passes through the sand storage chamber (30), and is arranged inside the screw conveyor (40). The transmission shaft (32) is provided with a second spiral plate (42) inside the screw conveyor (40), and the height of the second spiral plate (42) is the same as the inner diameter of the screw conveyor (40).

10. The double-circulation spiral conveying sand bailing device for coalbed methane horizontal wells according to claim 3, characterized in that: The medium flows into a storage tank through the annulus between the power oil pipe (10) and the high-pressure inner pipe (9); the storage tank is arranged on the ground; the delivery pipe (7) is connected to the storage tank; and the medium is high-pressure water or compressed air.

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