Long-life pulse generating device for measurement while drilling

Abstract

The invention discloses a long-life pulse generating device for measurement while drilling, which belongs to the technical field of measurement while drilling, and comprises a pulse generating device body internally provided with a driving motor, a stator rotary valve and a rotor rotary valve, and the output end of the driving motor is connected with a driving shaft fixed with the rotor rotary valve; the position, close to the axis of the end of the rotor rotary valve, of the driving shaft is hollow, a guide-out hole communicated with the hollow position is formed in the side end of the driving shaft, the driving motor drives the rotor rotary valve to rotate through the driving shaft, so that the stator rotary valve and the rotor rotary valve are opened or closed, and after the stator rotary valve and the rotor rotary valve are opened, the upper end of the stator rotary valve is communicated with the hollow position. Slurry flows into the hollow cavity from the upper end of the stator rotary valve and then is discharged through the guide-out hole.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of measurement while drilling, and particularly relates to a long-service-life pulse generating device for measurement while drilling. BACKGROUND

[0002] The mud pulse generator is the most important part of the wireless measurement while drilling instrument, and is used in the mud environment of high temperature, high pressure and strong vibration downhole, and is required to have good adaptability, high reliability, good signal quality and simple maintenance. At present, there are mainly three kinds of mud pulse generators used in oil drilling, namely, negative pulse, positive pulse and continuous wave system. Among them, the continuous wave system generates a fixed frequency pressure continuous wave by using a rotary valve, and encodes and decodes information according to the phase shift of the continuous wave. In the working process, the high-pressure drilling fluid passes through the inside of the continuous wave mud pulse generator, and the rotary valve in each component needs to bear a large pressure, which is easy to be damaged, thereby affecting the overall service life of the mud pulse generator. Therefore, the related components inside the continuous wave mud pulse generator need to be redesigned to make the distribution among the components more balanced and reduce the pressure at the rotary valve.

[0003] According to the search, the specification of patent application No. CN201621257732.X discloses a continuous wave mud pulse generator pressure balance assembly, which comprises a shell, a transmission shaft, a pressure bearing support and a rotary valve fixedly arranged in the shell, the rotary valve comprises a rotor cylinder driven by the transmission shaft and a stator cylinder, the pressure bearing support is arranged above the rotary valve and cooperates with the rotor cylinder, the lower end of the transmission shaft is provided with a plurality of steps, penetrates through the pressure bearing support and is provided with an external thread, the inner wall of the rotor cylinder is provided with an internal thread matched with the lower end of the transmission shaft, the inside of the upper segment of the rotor cylinder is radially expanded to form a pressure ring cavity, the lower segment of the rotor cylinder is narrower than the upper segment, and a rotor side hole is formed in the side wall of the lower segment. The transmission shaft is axially provided with a flow guide blind hole, and the side surface is provided with a flow guide side hole communicating the pressure ring cavity and the flow guide blind hole. The continuous wave mud pulse generator pressure balance assembly can effectively reduce the pressure at the rotary valve during use, and is helpful to prolong the overall service life of the mud pulse generator.

[0004] Based on the above search, combined with the prior art, it is found that in the process of rotating the rotary valve of the existing measurement while drilling pulse generating device to control the on-off of the mud, a shear force is generated on the mud. Since the mud contains sand particles with large particle size, the valve port of the rotary valve is easily worn, and therefore a material with high strength needs to be used at the valve port relative to other positions of the valve body. However, for a rotary valve with a large valve port diameter, the valve port circumference is relatively long, and the demand for high-strength material at the valve port is relatively large, which results in high manufacturing cost, otherwise the service life of the rotary valve is short. Therefore, a long-service-life pulse generating device for measurement while drilling is proposed to solve the above problems. SUMMARY

[0005] The purpose of this invention is to solve the technical problem that needs to be addressed in the prior art. For rotary valves with large valve orifice diameters, the demand for high-strength materials at the valve orifice is correspondingly large, resulting in high manufacturing costs. Otherwise, there will be a problem of short service life of the rotary valve. The invention provides a long-life pulse generator for drilling measurement. After the stator rotary valve and rotor rotary valve are opened, the upper end of the stator rotary valve is connected to the hollow cavity. The mud flows into the hollow cavity from the upper end of the stator rotary valve and is then discharged through the outlet hole.

[0006] This invention is achieved through the following technical solution: A long-life pulse generator for measurement while drilling includes a pulse generator body with a built-in drive motor, a stator rotary valve, and a rotor rotary valve. The stator rotary valve is fixedly connected to the inner wall of the pulse generator body. The output end of the drive motor is connected to a drive shaft fixed to the rotor rotary valve. The end of the drive shaft near the rotor rotary valve is hollow, and the side end of the drive shaft is provided with an outlet hole communicating with the hollow position. The drive motor drives the rotor rotary valve to rotate through the drive shaft, so that the stator rotary valve and the rotor rotary valve open or close. When the stator rotary valve and the rotor rotary valve are open, the upper end of the stator rotary valve is connected to the hollow position.

[0007] Preferably, the drive shaft is coaxially fixed with a connecting shaft, and the diameter of the connecting shaft is smaller than the hollow inner diameter of the drive shaft. The connecting shaft passes through the rotor valve and the stator valve in sequence and is connected to the fixed sleeve. The top of the fixed sleeve is sealed, and a screening ring is sleeved on the outer side of the fixed sleeve. The periphery of the screening ring is in contact with the inner wall of the pulse generator body. An inlet hole is provided on the fixed sleeve near the upper surface of the screening ring.

[0008] Preferably, the rotor rotary valve is provided with an outer rotary valve port and an inner rotary valve port along its radial path, and the outer rotary valve port is located on the outer side of the circumference where the fixed sleeve and the drive shaft are located, and the inner rotary valve port is located on the inner side of the circumference where the fixed sleeve and the drive shaft are located; the stator rotary valve is provided with an outer stator valve port and an inner stator valve port along its radial path, and the outer stator valve port and the inner stator valve port are respectively provided corresponding to the outer rotary valve port and the inner rotary valve port.

[0009] Preferably, the screening ring is a conical ring, and the diameter of the screening ring decreases from top to bottom.

[0010] Preferably, the screening ring is provided with an anti-clogging structure on the side near the stator rotary valve. The anti-clogging structure includes a suspension column, a fixed column, and a first elastic pressure member. The fixed column is fixed to the inner wall of the pulse generator body. The suspension column is connected to the fixed column through the first elastic pressure member, and the suspension column is in contact with the lower surface of the screening ring. The end face of the suspension column away from the first elastic pressure member is provided with a clearing part that matches the screen hole of the screening ring. A limiting sleeve is installed between the suspension column and the fixed column, and the limiting sleeve is sleeved on the outside of the first elastic pressure member.

[0011] Preferably, the unblocking part is a sphere, and the unblocking part is movably installed on the suspension column.

[0012] Preferably, it also includes a flow-limiting structure. The pulse generator body is provided with a pressure-reducing hole on the side of the screening ring away from the stator rotary valve. The flow-limiting structure controls the amount of mud passing through the pressure-reducing hole so that: when the stator rotary valve and the rotor rotary valve are fully connected, the flow-limiting structure controls the amount of mud passing through the pressure-reducing hole to be the minimum; when the stator rotary valve and the rotor rotary valve are fully closed, the flow-limiting structure controls the amount of mud passing through the pressure-reducing hole to be the maximum, so as to alleviate the pressure of mud on the rotor rotary valve.

[0013] Preferably, the flow-limiting structure includes a flow-limiting plate, which is fixed to the top of the screening ring and slides against the inner wall of the pulse generator body. The flow-limiting plate is offset from the position of the outer rotary valve port. The flow-limiting plate rotates synchronously with the screening ring and the rotor rotary valve, so that: when the stator rotary valve and the rotor rotary valve are fully connected, the flow-limiting plate covers the pressure-reducing hole, and no mud passes through the pressure-reducing hole at this time, and the mud flow is minimal, which is zero; when the stator rotary valve and the rotor rotary valve are fully closed, the flow-limiting plate is offset from the pressure-reducing hole, and the mud flow at the pressure-reducing hole is maximized, so as to alleviate the pressure of mud on the rotor rotary valve.

[0014] Preferably, the flow restrictor is a curved isosceles triangle, and the isosceles positions on both sides do not contact the screening ring; the curved isosceles triangle shape of the flow restrictor makes the amount of mud passing through the pressure reducing hole change inversely with the mud flow rate between the stator and rotor valves.

[0015] Preferably, the flow-limiting structure includes a flow-limiting block and a second elastic pressure member. A groove is provided on the side wall of the pressure-reducing hole. The flow-limiting block is fixed to the inner side of the groove by the second elastic pressure member, and the flow-limiting block is slidably fitted with the groove. The end face of the flow-limiting block facing the inner side of the pulse generator body is set as an inclined surface. This ensures that when the stator rotary valve and the rotor rotary valve are fully connected, the flow-limiting block blocks the pressure-reducing hole under the action of the second elastic pressure member, and the mud flow at the pressure-reducing hole is minimized. When the stator rotary valve and the rotor rotary valve are fully closed, the flow-limiting block squeezes the second elastic pressure member into the groove, thereby maximizing the mud flow at the pressure-reducing hole and relieving the pressure of the mud on the rotor rotary valve.

[0016] Compared with the prior art, the present invention has the following advantages and beneficial effects: I. The present invention provides a long-life pulse generator for drilling measurement. After the stator rotary valve and the rotor rotary valve are opened, the upper end of the stator rotary valve is connected to the hollow cavity. The mud flows into the hollow cavity from the upper end of the stator rotary valve and is then discharged through the outlet hole.

[0017] II. The present invention provides a long-life pulse generator for drilling measurement, which, without changing the flow rate of the mud per unit time, divides the mud flow containing sand and gravel particles of different sizes, and sets a high-strength structure only at the valve port for the mud flow containing larger-sized sand and gravel particles. This can save on the use of high-strength materials to a certain extent, reduce manufacturing costs, and effectively ensure the purity and quality of the high-strength structure, thereby helping to extend the service life of the pulse generator.

[0018] III. The present invention provides a long-life pulse generator for measurement while drilling. During the rotation of the rotor valve, the mud flow containing larger-diameter sand and gravel particles flows out from between the inner fixed valve port and the inner rotary valve port, and the high-strength edge of the inner fixed valve port and the inner rotary valve port forms a shearing action with the mud. The mud flow containing smaller-diameter sand and gravel particles flows out from between the outer fixed valve port and the outer rotary valve port. Since it does not contain large-diameter sand and gravel particles, the shearing action here is less likely to cause wear on the edge of the outer fixed valve port and the outer rotary valve port.

[0019] IV. The present invention provides a long-life pulse generator for drilling measurement, and the anti-clogging structure effectively prevents the screening ring from clogging.

[0020] V. The present invention provides a long-life pulse generator for drilling measurement. The flow limiting device alleviates the pressure of mud on the rotor valve, thereby helping to extend the overall service life of the mud pulse generator. Attached Figure Description

[0021] Figure 1 This is a schematic diagram of the structure of Embodiment 1 in the invention; Figure 2 This is a partial structural diagram of Embodiment 2 of the invention; Figure 3 for Figure 2 Enlarged structural diagram at point A; Figure 4 This is a three-dimensional structural diagram of the fixing sleeve and drive shaft in Embodiment 2 of the invention; Figure 5 This is a three-dimensional structural diagram of the stator rotary valve and rotor rotary valve in Embodiment 2 of the invention; Figure 6 This is a partial structural schematic diagram of Embodiment 3 of the invention; Figure 7 This is a three-dimensional structural diagram of the flow restrictor and screening ring in Embodiment 2 of the invention. Figure 8 This is a partial structural schematic diagram of Embodiment 4 of the invention; Figure 9 for Figure 8 Enlarged structural diagram at point B; Figure 10 This is a demonstration diagram showing the process of the valve opening between the stator rotary valve and the rotor rotary valve gradually increasing in Embodiment 2 of the invention. Figure 11 This is a demonstration diagram showing the maximum open valve port between the stator rotary valve and the rotor rotary valve in Embodiment 2 of the invention; Figure 12 This is a demonstration diagram showing the process of the conduction valve port between the stator rotary valve and the rotor rotary valve gradually decreasing in Embodiment 2 of the invention.

[0022] The components are: 1. Pulse generator body; 2. Stator rotary valve; 201. Outer stator valve port; 202. Inner stator valve port; 3. Rotor rotary valve; 301. Outer rotary valve port; 302. Inner rotary valve port; 4. Drive shaft; 5. Pressure reducing hole; 6. Connecting shaft; 7. Fixing sleeve; 8. Screening ring; 9. Inlet hole; 10. Outlet hole; 11. Suspension column; 12. Unblocking part; 13. Limiting sleeve; 14. First elastic pressure member; 15. Fixing column; 16. Flow limiting plate; 17. Flow limiting block; 18. Second elastic pressure member; 19. Groove. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to embodiments, but the implementation of the present invention is not limited thereto.

[0024] Example 1 like Figures 1-5 As shown, this embodiment provides a long-life pulse generator for drilling measurement, including a pulse generator body 1 with a built-in drive motor, stator valve 2 and rotor valve 3. The stator valve 3 is fixedly connected to the inner wall of the pulse generator body 1. The output end of the drive motor is connected to a drive shaft 4 fixed to the rotor valve 3. The end of the drive shaft 4 near the rotor valve 3 is hollow, and the side end of the drive shaft 4 is provided with an outlet hole 10 communicating with the hollow position. The drive motor drives the rotor valve 3 to rotate through the drive shaft 4, so that the stator valve 2 and rotor valve 3 open or close. After the stator valve 2 and rotor valve 3 are opened, the upper end of the stator valve 2 is connected to the hollow position.

[0025] Example 2 The difference between this embodiment and embodiment 1 is that: the drive shaft 4 is coaxially fixed with a connecting shaft 6, and the diameter of the connecting shaft 6 is smaller than the hollow inner diameter of the drive shaft 4. The connecting shaft 6 passes through the rotor valve 3 and the stator valve 2 in sequence and is connected to the fixed sleeve 7. The top of the fixed sleeve 7 is sealed, and a screening ring 8 is sleeved on the outer side of the fixed sleeve 7. The periphery of the screening ring 8 is in contact with the inner wall of the pulse generator body 1. An inlet hole 9 is provided on the fixed sleeve 7 close to the upper surface of the screening ring 8.

[0026] The rotor valve 3 has an outer valve port 301 and an inner valve port 302 along its radial path. The outer valve port 301 is located on the outer side of the circumference of the fixed sleeve 7 and the drive shaft 4, and the inner valve port 302 is located on the inner side of the circumference of the fixed sleeve 7 and the drive shaft 4. The stator valve 2 has an outer stator valve port 201 and an inner stator valve port 202 along its radial path. The outer stator valve port 201 and the inner stator valve port 202 are respectively provided corresponding to the outer valve port 301 and the inner valve port 302. The structure at the edges of the inner stator valve port 202 and the inner valve port 302 is made of high-strength material. The high-strength material is the best wear-resistant material in the field. The fixed sleeve 7 is connected to the hollow part of the drive shaft 4 through the inner stator valve port 202 and the inner valve port 302.

[0027] By using the valve ports located inside and outside the stator rotary valve 2 and the rotor rotary valve 3, and in conjunction with the screening ring 8, larger-diameter sand and gravel particles in the slurry can be screened out. The slurry flow containing larger-diameter sand and gravel particles flows into the fixed sleeve 7 through the inlet hole 9, while the slurry flow containing smaller-diameter sand and gravel particles passes through the screening ring 8 and is separated from the slurry flow containing larger-diameter sand and gravel particles. During the rotation of the rotor rotary valve 3, the slurry flow containing larger-diameter sand and gravel particles flows out from between the inner fixed valve port 202 and the inner rotary valve port 302, utilizing the high-strength edges of the inner fixed valve port 202 and the inner rotary valve port 302 to form a shearing action with the slurry. The slurry flow containing smaller-diameter sand and gravel particles flows out from between the outer fixed valve port 201 and the outer rotary valve port 301. Since it does not contain large-diameter sand and gravel particles, the shearing action here is less likely to cause wear on the edges of the outer fixed valve port 201 and the outer rotary valve port 301.

[0028] Based on the above structural configuration, without changing the flow rate of the mud per unit time, the mud flow containing sand and gravel particles of different sizes is diverted. Furthermore, a high-strength structure is only installed at the valve port used for the mud flow containing larger-sized sand and gravel particles. This can save on the amount of high-strength materials used and reduce manufacturing costs. At the same time, it can effectively ensure the purity and quality of the high-strength structure, thereby helping to extend the service life of the pulse generator.

[0029] Among them, the screening ring 8 is a conical ring, and the diameter of the screening ring 8 decreases from top to bottom; it can increase the screening area, improve the screening effect, and at the same time play a good guiding role for the mud flow.

[0030] The screening ring 8 is provided with an anti-clogging structure on the side near the stator rotary valve 2 to effectively prevent the screening ring 8 from clogging. The anti-clogging structure includes a suspension column 11, a fixed column 15, and a first elastic pressure member 14. The fixed column 15 is fixed to the inner wall of the pulse generator body 1. The suspension column 11 is fixed to the fixed column 15 through the first elastic pressure member 14, and the suspension column 11 is in contact with the lower surface of the screening ring 8. The end face of the suspension column 11 away from the first elastic pressure member 14 is provided with a clearing part 12 that is adapted to the screen hole of the screening ring 8. A limiting sleeve 13 is installed between the suspension column 11 and the fixed column 15. The limiting sleeve 13 is sleeved on the outside of the first elastic pressure member 14.

[0031] The screening ring 8 is fixedly sleeved on the outside of the fixed sleeve 7 and slides against the inner wall of the pulse generator body 1. As the fixed sleeve 7 rotates, the screening ring 8 can continuously rub against the unblocking part 12 on the suspension column 11, thereby unblocking the screen holes on the screening ring 8 by using the unblocking part 12.

[0032] The unblocking part 12 is a sphere and is movably installed on the suspension column 11; this can reduce the friction between it and the screening ring 8.

[0033] Example 3 The difference between this embodiment and embodiment 2 is that a flow-limiting structure is added, which enables this application to alleviate the pressure of mud on the rotor valve 3, thereby helping to extend the overall service life of the mud pulse generator. The pulse generator body 1 is provided with a pressure-reducing hole 5 on the side of the screening ring 8 away from the stator valve 2. The flow-limiting structure controls the amount of mud passing through the pressure-reducing hole 5, so that: when the stator valve 2 and the rotor valve 3 are fully connected, the flow-limiting structure controls the amount of mud passing through the pressure-reducing hole 5 to be the minimum; when the stator valve 2 and the rotor valve 3 are fully closed, the flow-limiting structure controls the amount of mud passing through the pressure-reducing hole 5 to be the maximum, so as to alleviate the pressure of mud on the rotor valve 3.

[0034] like Figures 6-7 As shown, the flow-limiting structure includes a flow-limiting plate 16, which is fixed to the top of the screening ring 8 and slides against the inner wall of the pulse generator body 1. The flow-limiting plate 16 is offset from the outer rotary valve port 301. The flow-limiting plate 16 rotates synchronously with the screening ring 8 and the rotor rotary valve 3, so that: when the stator rotary valve 2 and the rotor rotary valve 3 are fully connected, the flow-limiting plate 16 covers the pressure-reducing hole 5, and no mud passes through the pressure-reducing hole 5, with the mud flow rate being minimal (zero); when the stator rotary valve 2 and the rotor rotary valve 3 are fully closed, the flow-limiting plate 16 is offset from the pressure-reducing hole 5, and the mud flow rate at the pressure-reducing hole 5 is maximum. Figures 10-12 As shown, this is to alleviate the pressure of the mud on the rotor valve 3, thereby helping to extend the overall service life of the mud pulse generator.

[0035] Among them, the flow restrictor 16 is a curved isosceles triangle shape, and the isosceles positions on both sides do not contact the screening ring 8; the curved isosceles triangle shape of the flow restrictor 16 makes the mud flow rate at the pressure reducing hole 5 change inversely with the mud flow rate between the stator rotary valve 2 and the rotor rotary valve 3, thus ensuring the stability of the mud flow rate between the stator rotary valve 2 and the rotor rotary valve 3.

[0036] Example 4 The difference between this embodiment and Embodiment 3 is as follows: Figure 8 and Figure 9 As shown, the flow-limiting structure includes a flow-limiting block 17 and a second elastic pressure member 18. A groove 19 is provided on the side wall of the pressure-reducing hole 5. The flow-limiting block 17 is fixed to the inner side of the groove 19 by the second elastic pressure member 18, and the flow-limiting block 17 and the groove 19 are slidably fitted together. The end face of the flow-limiting block 17 facing the inner side of the pulse generator body 1 is set as an inclined surface. This allows the flow-limiting block 17 to block the pressure-reducing hole 5 under the action of the second elastic pressure member 18 when the stator valve 2 and the rotor valve 3 are fully connected, resulting in the minimum mud flow rate at the pressure-reducing hole 5. When the stator valve 2 and the rotor valve 3 are fully closed, the flow-limiting block 17 squeezes the second elastic pressure member 18 into the groove 19, resulting in the maximum mud flow rate at the pressure-reducing hole 5, thereby relieving the pressure of the mud on the rotor valve 3.

[0037] Compared to existing technologies, this invention, through the valve ports located inside and outside the stator rotary valve 2 and rotor rotary valve 3, in conjunction with the screening ring 8, can screen out larger-diameter sand and gravel particles in the slurry. The slurry flow containing larger-diameter sand and gravel particles flows into the fixed sleeve 7 through the inlet hole 9, while the slurry flow containing smaller-diameter sand and gravel particles passes through the screening ring 8 and is separated from the slurry flow containing larger-diameter sand and gravel particles. During the rotation of the rotor rotary valve 3, the slurry flow containing larger-diameter sand and gravel particles flows out from between the inner fixed valve port 202 and the inner rotary valve port 302, utilizing the high-strength edge of the inner fixed valve port 202 and the inner rotary valve port 302 to form a shearing action with the slurry; the slurry flow containing smaller-diameter sand and gravel particles flows out from between the inner fixed valve port 202 and the inner rotary valve port 302. The mud flow containing sand and gravel particles of different sizes flows out from between the outer fixed valve port 201 and the outer rotating valve port 301. Since it does not contain large-diameter sand and gravel particles, the shearing action here is unlikely to cause wear on the edges of the outer fixed valve port 201 and the outer rotating valve port 301. The above design, without changing the mud flow rate per unit time, diverts the mud flow containing sand and gravel particles of different sizes. High-strength structures are only set at the valve ports used for mud flow containing larger-diameter sand and gravel particles. This can save on the use of high-strength materials to a certain extent, reduce manufacturing costs, and effectively ensure the purity and quality of the high-strength structure, thereby helping to extend the service life of the pulse generator. Compared with the prior art, the present invention alleviates the pressure of mud on the rotor valve 3 by setting a flow limiting structure, thereby helping to extend the overall service life of the mud pulse generator.

[0038] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Any simple modifications or equivalent changes made to the above embodiments based on the technical essence of the present invention shall fall within the protection scope of the present invention.

Claims

1. A long-life pulse generator for measurement while drilling, characterized in that: The device includes a pulse generator body with a built-in drive motor, stator rotary valve, and rotor rotary valve. The stator rotary valve is fixedly connected to the inner wall of the pulse generator body. The output end of the drive motor is connected to a drive shaft fixed to the rotor rotary valve. The end of the drive shaft near the rotor rotary valve is hollow, and the side end of the drive shaft is provided with an outlet hole that communicates with the hollow position. The drive motor drives the rotor rotary valve to rotate through the drive shaft, so that the stator rotary valve and rotor rotary valve open or close. After the stator rotary valve and rotor rotary valve are opened, the upper end of the stator rotary valve is connected to the hollow position.

2. The long-life pulse generator for measurement while drilling according to claim 1, characterized in that: The drive shaft is coaxially fixed with a connecting shaft, and the diameter of the connecting shaft is smaller than the hollow inner diameter of the drive shaft. The connecting shaft passes through the rotor valve and the stator valve in sequence and is connected to the fixed sleeve. The top of the fixed sleeve is sealed, and a screening ring is fitted on the outer side of the fixed sleeve. The periphery of the screening ring is in contact with the inner wall of the pulse generator body. An inlet hole is provided on the fixed sleeve close to the upper surface of the screening ring.

3. A long-life pulse generator for measurement while drilling according to claim 2, characterized in that: The rotor valve has an outer rotary valve port and an inner rotary valve port along its radial path, with the outer rotary valve port located on the outer side of the circumference of the fixed sleeve and the drive shaft, and the inner rotary valve port located on the inner side of the circumference of the fixed sleeve and the drive shaft; the stator valve has an outer stator valve port and an inner stator valve port along its radial path, with the outer stator valve port and the inner stator valve port respectively corresponding to the outer rotary valve port and the inner rotary valve port.

4. A long-life pulse generator for measurement while drilling according to claim 3, characterized in that: The screening ring is a conical ring, and the diameter of the screening ring decreases from top to bottom.

5. A long-life pulse generator for measurement while drilling according to claim 4, characterized in that: The screening ring is provided with an anti-clogging structure on the side near the stator rotary valve. The anti-clogging structure includes a suspension column, a fixed column, and a first elastic pressure member. The fixed column is fixed to the inner wall of the pulse generator body. The suspension column is connected to the fixed column through the first elastic pressure member, and the suspension column is in contact with the lower surface of the screen. The end face of the suspension column away from the first elastic pressure member is provided with a clearing part that matches the screen hole of the screening ring. A limiting sleeve is installed between the suspension column and the fixed column, and the limiting sleeve is sleeved on the outside of the first elastic pressure member.

6. A long-life pulse generator for measurement while drilling according to claim 5, characterized in that: The unblocking part is a sphere, and the unblocking part is movably installed on the suspension column.

7. A long-life pulse generator for measurement while drilling according to claim 1, characterized in that: It also includes a flow-limiting structure. The pulse generator body is located on the side of the screening ring away from the stator rotary valve and has a pressure-reducing hole. The flow-limiting structure controls the amount of mud passing through the pressure-reducing hole so that: when the stator rotary valve and the rotor rotary valve are fully connected, the flow-limiting structure controls the amount of mud passing through the pressure-reducing hole to be the minimum; when the stator rotary valve and the rotor rotary valve are fully closed, the flow-limiting structure controls the amount of mud passing through the pressure-reducing hole to be the maximum, so as to alleviate the pressure of mud on the rotor rotary valve.

8. A long-life pulse generator for measurement while drilling according to claim 7, characterized in that: The flow-limiting structure includes a flow-limiting plate, which is fixed to the top of the screening ring and slides against the inner wall of the pulse generator body. The flow-limiting plate is offset from the position of the outer rotary valve port. The flow-limiting plate rotates synchronously with the screening ring and the rotor rotary valve, so that: when the stator rotary valve and the rotor rotary valve are fully connected, the flow-limiting plate covers the pressure-reducing hole, and no mud passes through the pressure-reducing hole at this time, and the mud flow is minimal, which is zero; when the stator rotary valve and the rotor rotary valve are fully closed, the flow-limiting plate is offset from the pressure-reducing hole, and the mud flow at the pressure-reducing hole is maximized, so as to relieve the pressure of mud on the rotor rotary valve.

9. A long-life pulse generator for measurement while drilling according to claim 8, characterized in that: The flow restrictor is a curved isosceles triangle, and the isosceles positions on both sides do not contact the screening ring; the curved isosceles triangle shape of the flow restrictor makes the amount of mud passing through the pressure reducing hole change inversely with the mud flow rate between the stator and rotor valves.

10. A long-life pulse generator for measurement while drilling according to claim 7, characterized in that: The flow-limiting structure includes a flow-limiting block and a second elastic pressure member. A groove is provided on the side wall of the pressure-reducing hole. The flow-limiting block is fixed to the inner side of the groove by the second elastic pressure member, and the flow-limiting block and the groove are slidably fitted together. The end face of the flow-limiting block facing the inner side of the pulse generator body is set as an inclined surface. This allows the flow-limiting block to block the pressure-reducing hole under the action of the second elastic pressure member when the stator rotary valve and the rotor rotary valve are fully connected, resulting in the minimum mud flow at the pressure-reducing hole. When the stator rotary valve and the rotor rotary valve are fully closed, the flow-limiting block squeezes the second elastic pressure member into the groove, resulting in the maximum mud flow at the pressure-reducing hole, thereby relieving the pressure of the mud on the rotor rotary valve.

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