Oscillating short, screw drill and drilling system

Abstract

This invention provides an oscillating sub, a screw drill bit, and a drilling system. The oscillating sub includes a sub housing and a valve disc assembly disposed inside the sub housing. The valve disc assembly includes a stationary valve disc and a moving valve disc. The stationary valve disc is fixed relative to the sub housing in the circumferential direction, and one end of the moving valve disc is connected to a transmission connecting rod. The valve disc assembly has a central channel connecting its upstream and downstream sides. The stationary valve disc and the moving valve disc are respectively constructed with a first throttling orifice and a second throttling orifice located around the central channel. The sub housing has a first diversion orifice, and the moving valve disc has a second diversion orifice connecting the central channel and the first diversion orifice. Based on the technical solution of this invention, the rotation of the moving valve disc controls the alternating opening and closing of the throttling and diversion channels, which can cause the flow area within the oscillating sub to change periodically, resulting in periodic changes in the screw pressure drop. Ultimately, the pressure drop changes generate effective oscillation at the drill bit, enabling the screw drill bit to have the ability to increase speed and alleviate pressure build-up.

Description

Technical Field

[0001] This invention relates to the field of screw drilling technology, and particularly to an oscillating sub, a screw drilling tool, and a drilling system. Background Technology

[0002] A screw drill is a positive displacement downhole power drill that uses drilling fluid as its power source, converting fluid pressure energy into mechanical energy. When the mud pumped from the mud pump flows through a bypass valve into the motor, a pressure difference is created between the motor's inlet and outlet, driving the rotor to rotate around the stator's axis. The rotational speed and torque are then transmitted to the drill bit via a universal joint and a drive shaft, thus enabling drilling operations. However, conventional screw drills primarily provide torque to the drill bit and cannot change the drilling pressure at the drill bit.

[0003] During drilling in hard formations and ultra-long horizontal wells, the pressure transmitted to the drill bit near the drill bit is relatively low due to frictional resistance, a phenomenon known as "pressure drag." Hydraulic oscillators are commonly used on-site to address this issue. These tools generate high-frequency axial reciprocating oscillations, converting the static friction between the drill string and the wellbore into dynamic friction, thereby reducing frictional resistance. Currently, hydraulic oscillators are a relatively effective tool for reducing friction and drag; however, they suffer from high pressure drop, and their placement limitations prevent them from significantly reducing frictional resistance near the drill bit. Summary of the Invention

[0004] To address the problem that existing underwater oscillators cannot effectively reduce frictional resistance near the drill bit, this invention proposes an oscillating sub, a screw drill bit, and a drilling system.

[0005] In a first aspect, the present invention provides an oscillating sub, which includes a sub housing and a valve disc assembly disposed inside the sub housing. The valve disc assembly includes a stationary valve disc and a moving valve disc. The stationary valve disc is fixed relative to the sub housing in the circumferential direction. A first end of the moving valve disc abuts against the end of the stationary valve disc, and a second end of the moving valve disc is connected to a transmission link.

[0006] The valve disc assembly is configured with a central channel connecting its upstream and downstream sides. The stationary valve disc and the moving valve disc are respectively configured with a first throttling orifice and a second throttling orifice located on the periphery of the central channel. The short section shell is configured with a first diversion orifice, and the moving valve disc is configured with a second diversion orifice that can connect the central channel and the first diversion orifice.

[0007] The moving valve disc is configured to be driven by the transmission link to rotate around the axis of the central channel, so that the first throttling orifice and the second throttling orifice, as well as the first diverting orifice and the second diverting orifice, continuously switch between corresponding conduction and staggered blocking states.

[0008] In one embodiment, the short section housing has an assembly channel coaxial with the central channel, the valve disc assembly is disposed in the assembly channel, and the upstream and downstream ends of the central channel are respectively connected to the upstream and downstream of the assembly channel.

[0009] In one embodiment, a limiting groove is constructed on the inner wall of the assembly channel at a position corresponding to the stationary valve disc, and a limiting protrusion is constructed on the outer peripheral surface of the stationary valve disc. The limiting protrusions are fitted into the limiting groove and are mutually limited in the circumferential direction.

[0010] In one embodiment, the limiting groove extends axially along the assembly channel, and the extension length of the limiting groove is greater than the width of the limiting protrusion in the axial direction of the assembly channel.

[0011] In one embodiment, the end of the limiting groove corresponding to the stationary valve disc in the direction away from the moving valve disc is configured as an open opening, which is used for the limiting protrusion to enter and exit the limiting groove along the axial direction of the assembly channel.

[0012] In one embodiment, the central channel includes a first central hole constructed at the center of the stationary valve disc and a second central hole constructed at the center of the moving valve disc. The end of the second central hole is closed and constructed as the second end of the moving valve disc. The second central hole has a through hole on its wall near its closed end that connects the second central hole and the assembly channel in the radial direction.

[0013] In one embodiment, the through-hole is constructed as an oblique hole, wherein the portion of the oblique hole that is radially closer to the outer side is axially closer to the second end of the moving valve disc in the central channel.

[0014] In one embodiment, the second throttling orifice and the second diverting orifice are offset circumferentially from the moving valve disc, and the relative positions of the second throttling orifice and the second diverting orifice in the circumferential direction of the moving valve disc are configured such that when the second throttling orifice is connected to the first throttling orifice, the second diverting orifice is connected to the first diverting orifice.

[0015] In one embodiment, there are multiple first throttling orifices and / or multiple second throttling orifices, which are uniformly or non-uniformly distributed circumferentially.

[0016] In one embodiment, there are multiple first diversion holes and / or multiple second diversion holes, which are uniformly or non-uniformly distributed along the circumference.

[0017] In one embodiment, wear-resistant inner sleeves are provided in the first throttling orifice, the second throttling orifice, the first diversion orifice, and the second diversion orifice.

[0018] Secondly, the present invention provides a screw drill tool, which includes a screw rotor and the aforementioned oscillating sub-section, wherein the screw rotor is connected to the transmission link of the oscillating sub-section.

[0019] Thirdly, the drilling system proposed in this invention includes the aforementioned screw drill bit, and thus possesses all the technical effects it possesses.

[0020] The above-mentioned technical features can be combined in various suitable ways or replaced by equivalent technical features, as long as the purpose of the present invention can be achieved.

[0021] The oscillating sub, screw drill bit, and drilling system provided by this invention have at least the following advantages compared with the prior art:

[0022] This invention discloses an oscillating sub, a screw drill bit, and a drilling system. By controlling the alternating opening and closing of the throttling and branching channels through the rotation of the moving valve disc, the flow area of ​​the drilling fluid within the oscillating sub can be periodically changed, causing periodic changes in the displacement of the screw rotor. This results in periodic changes in the screw pressure drop, ultimately generating effective oscillation at the drill bit through the pressure drop changes. This enables the screw drill bit to achieve speed increases and alleviate pressure build-up. Furthermore, the overall structure of the oscillating sub is simple and can be directly optimized from components of conventional screw drill bits without the need to add new tools to the drill bit. Attached Figure Description

[0023] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0024] Figure 1 The diagram shows a cross-sectional view of the oscillation section of the present invention in one of its oscillation states;

[0025] Figure 2 This shows a cross-sectional view of the oscillation section of the present invention in another oscillation state;

[0026] Figure 3 Showing Figure 1 A schematic diagram of the orthographic projection of the structure shown;

[0027] Figure 4 Showing Figure 2 A schematic diagram of the orthographic projection of the structure shown;

[0028] Figure 5 A half-sectional view of the oscillating stub housing of the present invention is shown;

[0029] Figure 6A schematic diagram of the static valve disc in the oscillation subsection of the present invention is shown;

[0030] Figure 7 A schematic diagram of the moving valve disc in the oscillation subsection of the present invention is shown;

[0031] Figure 8 A cross-sectional view of the moving valve disc in the oscillation subsection of the present invention is shown.

[0032] In the accompanying drawings, the same parts use the same reference numerals. The drawings are not to scale.

[0033] Figure label:

[0034] 10-Short section housing, 101-First diversion hole, 102-Assembly channel, 103-Limiting groove, 20-Valve disc assembly, 201-Central channel, 21-Static valve disc, 211-First central hole, 212-First throttling hole, 213-Limiting protrusion, 22-Moving valve disc, 221-Second central hole, 222-Second throttling hole, 223-Second diversion hole, 224-Through hole, 30-Transmission connecting rod. Detailed Implementation

[0035] The invention will now be further described with reference to the accompanying drawings.

[0036] Example 1

[0037] An embodiment of the present invention provides an oscillation sub, which includes a sub housing 10 and a valve disc assembly 20 disposed inside the sub housing 10. The valve disc assembly 20 includes a stationary valve disc 21 and a moving valve disc 22. The stationary valve disc 21 is fixed relative to the sub housing 10 in the circumferential direction. The first end of the moving valve disc 22 abuts against the end of the stationary valve disc 21, and the second end of the moving valve disc 22 is connected to a transmission link 30.

[0038] The valve disc assembly 20 is constructed with a central channel 201 connecting its upstream and downstream sides. The stationary valve disc 21 and the moving valve disc 22 are respectively constructed with a first throttling orifice 212 and a second throttling orifice 222 located on the periphery of the central channel 201. The short section housing 10 is constructed with a first diversion orifice 101, and the moving valve disc 22 is constructed with a second diversion orifice 223 that can connect the central channel 201 and the first diversion orifice 101.

[0039] The moving valve disc 22 is configured to be driven by the transmission link 30 to rotate around the axis of the central channel 201, so that the first throttling orifice 212 and the second throttling orifice 222, as well as the first diverting orifice 101 and the second diverting orifice 223, continuously switch between corresponding conduction and staggered blocking states.

[0040] Specifically, as shown in the attached diagram. Figure 1 and Figure 2As shown, the oscillating sub mainly includes a sub housing 10 and a valve disc assembly 20 disposed inside the sub housing 10. One end of the transmission connecting rod 30 extends into the sub housing 10 and connects to the valve disc assembly 20. The sub housing 10 has an overall cylindrical structure. The sub housing 10 can be directly based on the release housing of the anti-drop assembly of a conventional screw drill bit, and the structure of the release housing is optimized to obtain the sub housing 10 of the present invention. The two ends of the sub housing 10 are respectively constructed with external thread structure and internal thread structure, which are used to connect to the bypass valve assembly and the motor assembly, respectively. The sub housing 10 has a channel for drilling fluid to flow (i.e., the assembly channel 102 mentioned later). The valve disc assembly 20 can block the channel as a whole, but the central channel 201 opened in the center of the valve disc assembly 20 can keep the channel inside the sub housing 10 open, serving as the main channel for drilling fluid to flow. The valve disc assembly 20 is composed of a stationary valve disc 21 and a moving valve disc 22 arranged sequentially along the axis of the central channel 201, that is, the central channel 201 is formed simultaneously in the stationary valve disc 21 and the moving valve disc 22.

[0041] In addition to the main channel formed by the central channel 201, the stationary valve disc 21, the moving valve disc 22, and the short section shell 10 also form two secondary channels for drilling fluid flow. These include a throttling channel formed by the first throttling orifice 212 and the second throttling orifice 222, and a branching channel formed by the first branching orifice 101 and the second branching orifice 223. However, these two secondary channels are different from the always-conducting central channel 201. They are not always-conducting, but are alternately opened and closed as the moving valve disc 22 rotates, thereby causing changes in the flow area for drilling fluid flow, changes in drilling fluid flow rate, and thus changes in pressure drop and differential pressure, ultimately producing an oscillation effect.

[0042] Specifically, the stationary valve disc 21 is fixed relative to the short section housing 10 in the circumferential direction, while the moving valve disc 22 is movable relative to the short section housing 10 in the circumferential direction. Driven by the transmission link 30, the moving valve disc 22 makes a selection, while the stationary valve disc 21 remains stationary. Therefore, in the oscillating short section, the stationary valve disc 21 and the short section housing 10 are relatively stationary components, while the moving valve disc 22 is a relatively moving component. Thus, when the moving valve disc 22 rotates around the axis of the central channel 201, the central channel 201 remains open, and the second throttling orifice 222 and the second diverting orifice 223 alternately correspond to or are offset from the first throttling orifice 212 and the first diverting orifice 101, respectively, as the moving valve disc 22 rotates.

[0043] When the second throttling orifice 222 is connected to the first throttling orifice 212 and the second branch orifice 223 is connected to the first branch orifice 101, the drilling fluid upstream of the sub-section housing 10 can pass through the valve disc assembly 20 to the downstream via the throttling channel formed by the first throttling orifice 212 and the second throttling orifice 222. Simultaneously, the drilling fluid upstream of the sub-section housing 10 can also pass through the central channel 201 to the downstream, and the drilling fluid entering the central channel 201 can also flow radially to the outside of the sub-section housing 10 via the branch orifice 223 and the first branch orifice 101. The throttling channel can control the flow area inside the oscillating sub-section, thereby changing the drilling fluid pressure and adjusting the pressure drop and differential pressure. The branch orifice connects the inside and outside of the oscillating sub-section. When the branch orifice is open, the inside and outside of the oscillating sub-section are connected, and some drilling fluid flows outside the oscillating sub-section, resulting in a decrease in flow rate, torque, and pressure drop through the oscillating sub-section to the lower screw, further increasing the differential pressure and making the oscillation force greater. When the moving valve disc 22 rotates to open the throttling channel and / or the branching channel, the flow area of ​​the drilling fluid increases, the pressure difference decreases, and the overall pressure drop of the drill string decreases. When the moving valve disc 22 rotates to block the throttling channel and / or the branching channel, the flow area of ​​the drilling fluid decreases, the pressure difference increases, and the overall pressure drop of the drill string increases. At this time, the screw drill string operates at a large displacement, and the torque of the screw increases.

[0044] The technical solution of this invention utilizes the rotation of the moving valve disc 22 to control the alternating opening and closing of the throttling channel and the diverting channel, which can cause the flow area of ​​the drilling fluid in the oscillating sub to change periodically, resulting in a periodic change in the discharge of the screw rotor, thereby causing a periodic change in the screw pressure drop. Ultimately, the change in pressure drop generates effective oscillation at the drill bit, enabling the screw drill to have the ability to increase speed and relieve pressure. Moreover, the overall structure of the oscillating sub is simple and can be directly optimized from the components of conventional screw drills without adding new tools to the drill.

[0045] Preferably, the second throttling orifice 222 and the second diverting orifice 223 are offset in the circumferential direction of the moving valve disc 22. The relative positions of the second throttling orifice 222 and the second diverting orifice 223 in the circumferential direction of the moving valve disc 22 are configured such that when the second throttling orifice 222 is connected to the first throttling orifice 212, the second diverting orifice 223 is connected to the first diverting orifice 101.

[0046] Specifically, as shown in the attached diagram. Figure 7 and Figure 8As shown, the second throttling orifice 222 and the second diverting orifice 223 are offset circumferentially from each other on the moving valve disc 22. By designing the relative positions of the second throttling orifice 222 and the second diverting orifice 223 on the moving valve disc 22 (and also considering the relative positions of the first throttling orifice 212 on the stationary valve disc 21 and the first diverting orifice 101 on the short section housing 10), the throttling channel formed by the second throttling orifice 222 and the first throttling orifice 212, and the diverting channel formed by the second diverting orifice 223 and the first diverting orifice 101, have the same on / off state at the same time. Therefore, when the throttling channel and the diverting channel are simultaneously open, the oscillating short section has the largest flow area; when the throttling channel and the diverting channel are simultaneously blocked, the oscillating short section has the smallest flow area. This ensures that the pressure difference and pressure drop have the largest variation amplitude during the rotation of the moving valve disc 22, maximizing the oscillation force.

[0047] Of course, depending on the needs, the throttling channel and the diverting channel can also be designed to have different on / off states at the same time.

[0048] Preferably, wear-resistant inner sleeves are provided in the first throttling orifice 212, the second throttling orifice 222, the first diversion orifice 101, and the second diversion orifice 223.

[0049] Specifically, the wear-resistant inner casing is made of cemented carbide and is installed inside the corresponding channel as a liner to prevent deformation of the channel due to drilling fluid erosion. The inner diameter of the wear-resistant inner casing can be adjusted according to site requirements and installed in real time. Installation can be done using threaded fit or interference fit.

[0050] Furthermore, there are multiple first throttling orifices 212 and / or multiple second throttling orifices 222, which are uniformly or non-uniformly distributed along the circumference; there are multiple first diversion orifices 101 and / or multiple second diversion orifices 223, which are uniformly or non-uniformly distributed along the circumference.

[0051] Specifically, taking the first throttling orifice 212 and the second throttling orifice 222 as examples, one or more of the first throttling orifice 212 and the second throttling orifice 222 can be arbitrarily set as needed. Thus, the correspondence between the two can be one-to-one, one-to-many, or many-to-many, thereby forming different numbers of throttling channels. When either the first throttling orifice 212 or the second throttling orifice 222 is set to multiple, they can be uniformly distributed or non-uniformly distributed in the circumferential direction. Uniform distribution can make the opening and closing of the throttling channel have a periodic pattern, while non-uniform distribution can make the opening and closing of the throttling channel non-periodic, thereby meeting different needs.

[0052] Furthermore, the short section housing 10 has an internal assembly channel 102 coaxial with the central channel 201. The valve disc assembly 20 is disposed in the assembly channel 102, and the upstream and downstream ends of the central channel 201 are respectively connected to the upstream and downstream ends of the assembly channel 102.

[0053] Specifically, as shown in the attached diagram. Figures 1 to 5 As shown, the assembly channel 102 is used to install the valve disc assembly 20 and also to supply drilling fluid. In principle, the valve disc assembly 20 closes the assembly channel 102. However, since the valve disc assembly 20 has a central channel 201, the assembly channel 102 can be connected through the central channel 201. Therefore, the central channel 201 and the assembly channel 102 constitute the main channel for supplying drilling fluid from upstream to downstream.

[0054] Furthermore, a limiting groove 103 is constructed on the inner wall of the assembly channel 102 at the position corresponding to the stationary valve disc 21, and a limiting protrusion 213 is constructed on the outer peripheral surface of the stationary valve disc 21. The limiting protrusion 213 is fitted in the limiting groove 103 and limits each other in the circumferential direction.

[0055] Specifically, as shown in the attached diagram. Figure 1 , Figure 2 and Figure 5 As shown, the relative fixation of the stationary valve disc 21 and the short section housing 10 in the circumferential direction is achieved by limiting grooves 103 and limiting protrusions 213. The limiting grooves 103 are formed on the inner wall of the assembly channel 102, and there is at least one such groove. When there are multiple limiting grooves 103, they are spaced apart in the circumferential direction of the assembly channel 102. The limiting protrusions 213 protrude from the outer circumferential surface of the stationary valve disc 21 (as shown in the attached figure). Figure 6 As shown, the limiting protrusion 213 is fitted into the limiting groove 103, and in the circumferential direction of the assembly channel 102, the two sides of the limiting protrusion 213 abut against the inner walls of the two sides of the limiting groove 103, thereby ensuring that the static valve disc 21 and the short section housing 10 are relatively stationary in the circumferential direction.

[0056] Preferably, the limiting groove 103 extends along the axial direction of the assembly channel 102, and the extension length of the limiting groove 103 is greater than the width of the limiting protrusion 213 in the axial direction of the assembly channel 102.

[0057] Specifically, as shown in the attached diagram. Figure 1 and Figure 2 As shown, the length of the limiting groove 103 in the axial direction of the assembly channel 102 is greater than the width of the limiting protrusion 213 in this direction. Therefore, for the stationary valve disc 21, it can move relative to the short section housing 10 in the axial direction of the assembly channel 102, adapting to the axial movement of the stationary valve disc 21 that may be caused by the oscillation of the oscillating short section.

[0058] Optionally, the end of the limiting groove 103 corresponding to the static valve disc 21 in the direction away from the dynamic valve disc 22 is constructed as an open opening. The open opening is used to allow the limiting protrusion 213 to enter and exit the limiting groove 103 along the axial direction of the assembly channel 102, which facilitates the installation of the static valve disc 21 in the assembly channel 102.

[0059] Furthermore, the central channel 201 includes a first central hole 211 constructed at the center of the stationary valve disc 21 and a second central hole 221 constructed at the center of the moving valve disc 22. The end of the second central hole 221 is closed and constructed as the second end of the moving valve disc 22. The second central hole 221 has a through hole 224 constructed on the hole wall near its closed end, which connects the second central hole 221 and the assembly channel 102 in the radial direction.

[0060] Specifically, the first central hole 211 on the stationary valve disc 21 and the second central hole 221 on the moving valve disc 22 together form the central channel 201, with the second central hole 221 always corresponding to the first central hole 211. (See attached diagram) Figure 8 As shown, the second central hole 221 can be considered as a blind hole closed at one end. The closed end of the second central hole 221 is mainly used to form the second end of the moving valve disc 22 for connection with the transmission connecting rod 30. Furthermore, the communication between the second central hole 221 and the assembly channel 102 is achieved through the through hole 224 on the wall of the second central hole 221. Further, the part where the through hole 224 is located is a reduced diameter section of the moving valve disc 22, and an annular gap is formed between the reduced diameter section and the inner wall of the assembly channel 102. This annular gap allows the through hole 224 to connect to the assembly channel 102.

[0061] Preferably, the through hole 224 and the second throttling hole 222 are offset from each other in the circumferential direction of the moving valve disc 22. This makes the fluid formed when the drilling fluid enters the downstream of the assembly channel 102 through the second throttling hole 222 and the fluid formed when the drilling fluid enters the downstream of the assembly channel 102 through the through hole offset from each other in the circumferential direction, so as to avoid impact between them and affect the fluidity, and improve the uniformity of the drilling fluid distribution in the circumferential direction.

[0062] Preferably, the through hole 224 is constructed as an oblique hole. The portion of the oblique hole that is closer to the outer side in the radial direction is closer to the second end of the moving valve disc 22 in the axial direction of the central channel 201. This can reduce the change in flow direction when the drilling fluid enters the through hole 224 from the second central hole 221 and reduce the impact of the change in flow direction on the fluidity of the drilling fluid.

[0063] Example 2

[0064] An embodiment of the present invention provides a screw drill tool, which includes a screw rotor and an oscillating sub-section of embodiment 1. The screw rotor is connected to the transmission connecting rod 30 of the oscillating sub-section. The screw drill tool has all the technical effects of the oscillating sub-section.

[0065] The screw rotor undergoes planetary motion driven by drilling fluid. During this motion, there is an eccentricity e. The transmission connecting rod 30 and the eccentric screw hole at the end of the moving valve disc of the oscillating section (see attached diagram) are connected. Figure 7 The rightmost hole of the moving valve disc shown is threaded, and the eccentricity of the eccentric screw hole is the same as the eccentricity of the screw rotor.

[0066] Example 3

[0067] An embodiment of the present invention provides a drilling system that includes the screw drill string of embodiment 2, thereby possessing all the technical effects thereof.

[0068] In the description of this invention, it should be understood that the terms "upper", "lower", "bottom", "top", "front", "rear", "inner", "outer", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention.

[0069] While the invention has been described herein with reference to specific embodiments, it should be understood that these embodiments are merely examples of the principles and applications of the invention. Therefore, it should be understood that many modifications can be made to the exemplary embodiments, and other arrangements can be designed without departing from the spirit and scope of the invention as defined by the appended claims. It should be understood that different dependent claims and features described herein can be combined in ways different from those described in the original claims. It is also understood that features described in conjunction with individual embodiments can be used in other described embodiments.

Claims

1. An oscillating stub, characterized by The device includes a short section housing and a valve disc assembly disposed inside the short section housing. The valve disc assembly includes a stationary valve disc and a moving valve disc. The stationary valve disc is fixed relative to the short section housing in the circumferential direction. The first end of the moving valve disc abuts against the end of the stationary valve disc, and the second end of the moving valve disc is connected to a transmission connecting rod. The valve disc assembly is configured with a central channel connecting its upstream and downstream sides. The stationary valve disc and the moving valve disc are respectively configured with a first throttling orifice and a second throttling orifice located on the periphery of the central channel. The short section shell is configured with a first diversion orifice, and the moving valve disc is configured with a second diversion orifice that can connect the central channel and the first diversion orifice. The moving valve disc is configured to be driven by the transmission link to rotate around the axis of the central channel, so that the first throttling orifice and the second throttling orifice, as well as the first diverting orifice and the second diverting orifice, continuously switch between corresponding conduction and staggered blocking states.

2. The oscillating stub of claim 1, wherein, The short section housing has an internal assembly channel coaxial with the central channel. The valve disc assembly is disposed within the assembly channel, and the upstream and downstream ends of the central channel are respectively connected to the upstream and downstream ends of the assembly channel.

3. The oscillating stub of claim 2, wherein, A limiting groove is constructed on the inner wall of the assembly channel at the position corresponding to the stationary valve disc, and a limiting protrusion is constructed on the outer circumferential surface of the stationary valve disc. The limiting protrusion is fitted into the limiting groove and limits each other in the circumferential direction.

4. The oscillation subsection according to claim 3, characterized in that, The limiting groove extends axially along the assembly channel, and the extension length of the limiting groove is greater than the width of the limiting protrusion in the axial direction of the assembly channel.

5. The oscillation subsection according to claim 3 or 4, characterized in that, The end of the limiting groove corresponding to the static valve disc away from the moving valve disc is constructed as an open opening, which is used for the limiting protrusion to enter and exit the limiting groove along the axial direction of the assembly channel.

6. The oscillation subsection according to claim 2, characterized in that, The central channel includes a first central hole constructed at the center of the stationary valve disc and a second central hole constructed at the center of the moving valve disc. The end of the second central hole is closed and constructed as the second end of the moving valve disc. The second central hole has a through hole on its wall near its closed end that connects the second central hole and the assembly channel in the radial direction.

7. The oscillation subsection according to claim 6, characterized in that, The through hole is constructed as an oblique hole, and the portion of the oblique hole that is radially closer to the outer side is axially closer to the second end of the moving valve disc in the central channel.

8. The oscillation subsection according to claim 1, characterized in that, The second throttling orifice and the second diverting orifice are offset in the circumferential direction of the moving valve disc. The relative positions of the second throttling orifice and the second diverting orifice in the circumferential direction of the moving valve disc are configured such that when the second throttling orifice is connected to the first throttling orifice, the second diverting orifice is connected to the first diverting orifice.

9. The oscillation sub-junction according to claim 1, characterized in that, The number of the first throttling orifice and / or the second throttling orifice is multiple, and the multiple first throttling orifices and / or multiple second throttling orifices are uniformly or non-uniformly distributed along the circumference.

10. The oscillation sub-junction according to claim 1, characterized in that, The number of the first diversion hole and / or the second diversion hole is multiple, and the multiple first diversion holes and / or multiple second diversion holes are evenly or unevenly distributed along the circumference.

11. The oscillation sub-junction according to claim 1, characterized in that, Wear-resistant inner sleeves are provided inside the first throttling orifice, the second throttling orifice, the first diverting orifice, and the second diverting orifice.

12. A screw drill bit, characterized in that, It includes a screw rotor and an oscillating sub as described in any one of claims 1 to 11, wherein the screw rotor is connected to the transmission link of the oscillating sub.

13. A drilling system, characterized in that, Including the screw drill as described in claim 12.

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