A multi-stage pulse oscillation screw

Abstract

The invention relates to a multi-stage pulse oscillation screw, which is composed of a bypass valve assembly, a first pulse assembly, a motor assembly, a universal shaft assembly, a second pulse assembly, and a transmission assembly; the bypass valve assembly is used to control the flow direction of drilling fluid; the first pulse assembly generates a periodic oscillation effect by periodically changing the flow area between the dynamic valve and the static valve, and pushes the hammer to compress the second spring to generate axial impact; the motor assembly is used to convert the pressure energy of drilling fluid into mechanical energy for the rotation of the motor rotor; the universal shaft assembly is used to convert the eccentric rotation of the motor rotor into fixed-axis rotation; the second pulse assembly generates a periodic oscillation effect by periodically changing the flow area between the water cap and the second pulse housing; the transmission assembly is used to transmit the rotational mechanical energy to the drill bit; the invention solves the problems of large friction resistance near the drill bit and shallow penetration depth of the drill bit in the prior art, and effectively reduces the friction resistance near the drill bit, increases the penetration depth of the drill bit, and improves the drilling efficiency through the multi-stage pulse effect.

Description

Technical Field

[0001] The invention relates to the technical field of oil drilling, and in particular to a multi-stage pulse oscillation screw. Background Art

[0002] With the development of oil and gas extraction technology, shallow oil and gas resources can no longer meet people's needs. Oil and gas extraction is developing towards complex wells such as deep wells, ultra-deep wells, horizontal wells and extended displacement wells. With the increase in the complexity of oil and gas wells, the "support pressure" of the downhole drill string and the insufficient penetration depth of the drill bit are becoming more and more serious, which seriously affects the drilling cycle. A single screw drill can provide the required torque to the drill bit, but it cannot solve the problems of large drill string friction and insufficient drill bit penetration depth; the use of hydraulic oscillators can better solve the problem of large drill string friction, but due to the limitation of the installation position of the hydraulic oscillator, it cannot solve the problem of large near drill bit friction and drill bit penetration. It is of great significance to propose a tool that can reduce the large near drill bit friction and increase the drill bit penetration depth.

[0003] In response to the above problems, a multi-stage pulse oscillation screw is proposed. This tool converts a part of the rotational mechanical energy generated by the motor assembly into multi-stage hydraulic pulses and axial impacts, effectively reducing the "support pressure" problem of the drill string, as well as the problems of high friction near the drill bit and insufficient penetration depth of the drill bit, greatly improving the efficiency of drilling machinery and shortening the drilling cycle. Summary of the invention

[0004] The purpose of the present invention is to provide a multi-stage pulse oscillation screw to solve the problems existing in the existing drilling technology, such as large friction resistance near the drill bit, insufficient penetration depth of the drill bit, low drilling efficiency, etc. Under the joint action of multi-stage pulses, the tool can effectively reduce the friction resistance near the drill bit, increase the penetration depth of the drill bit, and improve the drilling efficiency.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is:

[0006] A multi-stage pulse oscillation screw, mainly composed of a bypass valve assembly, a first pulse assembly, a motor assembly, a universal shaft assembly, a second pulse assembly and a transmission assembly; the bypass valve assembly is used to control the flow direction of drilling fluid; the first pulse assembly is placed above the motor assembly, and is used to convert the rotational mechanical energy of the motor assembly into the pulse action and axial impact of the first pulse assembly; the motor assembly is used to convert the liquid pressure energy of the drilling fluid into the mechanical energy of the motor rotor rotation; the universal shaft assembly is used to convert the eccentric rotation of the motor rotor into a fixed axis rotation around the axis; the second pulse assembly is placed below the universal shaft assembly, and is used to convert the rotational mechanical energy generated by the motor assembly into the pulse action of the second pulse assembly; the transmission assembly is used to transmit the rotational mechanical energy generated by the motor assembly to the drill bit.

[0007] The bypass valve assembly is provided with a bypass housing, a valve core, a first spring and a valve seat; the bypass housing is provided with a first central flow channel and a bypass side hole; the valve core is provided with a valve core central hole and a valve core side hole; the valve seat is provided with a valve seat central hole; the first central flow channel, the valve core central hole and the valve seat central hole are always connected; the first spring abuts between the valve core and the valve seat; a sealing device is provided between the valve core and the valve seat and the bypass housing.

[0008] The first pulse assembly is provided with a first pulse upper housing, a hammer, a second spring, a first pulse lower housing, a static valve, a dynamic valve, a dynamic valve seat, an anti-drop rod and a first retaining ring; the upper part of the first pulse upper housing is threadedly connected with the lower part of the bypass housing; the upper part of the first pulse lower housing is threadedly connected with the lower part of the first pulse upper housing; the first pulse upper housing is provided with a second central flow channel and a first stop; the hammer is provided with a first axial flow channel, a second axial flow channel and a second stop; the first axial flow channel is periodically connected with the second central flow channel; the second axial flow channel is always connected with the second central flow channel; the first The number of axial flow channels is 3 to 6; one end of the second spring abuts against the bottom of the first pulse upper shell, and the other end abuts against the top of the second stop; the hammer can slide axially along the first pulse upper shell, and the sliding stroke is 20 to 50 mm; it is worth noting that a sealing device is provided between the hammer and the first pulse upper shell and the first pulse lower shell; the first pulse lower shell is provided with a third stop, a static valve groove and a fourth stop; the static valve is installed in the static valve groove; the shape of the static valve groove is square, hexagonal and octagonal; the movable valve seat is provided with a movable valve groove and a first radial flow channel; the movable valve Installed in the movable valve groove; the shape of the movable valve groove is square, hexagonal and octagonal; the number of the first radial flow channels is 3 to 6; the anti-drop rod is provided with a first shaft shoulder; the lower part of the movable valve seat abuts on the first shaft shoulder and is connected to the upper part of the anti-drop rod through threads; the first retaining ring is provided with a third axial flow channel; the number of the third axial flow channels is 3 to 6; the first retaining ring abuts on the fourth abutment; a first cavity is formed between the hammer and the static valve; in particular: in the initial state, the hammer abuts on the third abutment under the action of the second spring; when the drilling fluid enters, the movable valve, The moving valve seat and the anti-drop rod rotate with the motor rotor. When the moving valve rotates to the point where the flow area of ​​the static valve is the smallest, a water hammer effect is generated in the first cavity. At the same time, the local high pressure pushes the hammer to compress the second spring upward. When the hammer moves upward to contact the second stop, the first axial flow channel is disconnected from the second central flow channel, the axial flow channel area is reduced, and a secondary water hammer effect is generated. When the moving valve continues to rotate until the flow area with the static valve is the largest, the first cavity is in a low-pressure state, and the hammer is accelerated downward to impact the first pulse lower shell to generate an axial impact under the combined action of the second spring and the pressure energy of the drilling fluid.

[0009] An axial through hole is provided between the moving valve and the static valve. The size, quantity and position of the axial through hole can be set in different combinations according to different working conditions to achieve different pulse effects.

[0010] The motor assembly is provided with a motor housing, a motor stator and a motor rotor; the upper part of the motor housing is threadedly connected to the lower part of the first pulse lower housing; the upper part of the motor rotor is threadedly connected to the lower part of the anti-drop rod; when drilling fluid enters, the motor rotor is driven to rotate under the action of the drilling fluid pressure difference.

[0011] The universal shaft assembly is provided with a universal shaft housing and a ball universal shaft assembly; the upper part of the universal shaft housing is threadedly connected to the lower part of the motor housing; the upper part of the ball universal shaft assembly is threadedly connected to the lower part of the motor rotor; the eccentric rotation of the motor rotor is converted into fixed axis rotation around the axis.

[0012] The second pulse assembly is provided with a second pulse housing and a water cap; the second pulse housing is provided with a first radial groove; the water cap is provided with a second radial flow channel, a third radial flow channel and a central hole of the water cap; the second radial flow channel and the third radial flow channel are always connected with the central hole of the water cap; the second radial flow channel is always connected with the first radial groove; the third radial flow channel is intermittently connected with the first radial groove; the number of the first radial grooves is 2 to 4; the number of the second radial flow channels is 3 to 6; the number of the third radial flow channels is consistent with the number of the first radial grooves; the flow area of ​​the third radial flow channel is 2 to 5 times that of the second radial flow channel; in particular: when the water cap is rotated to the third radial flow channel to be connected with the first radial groove, most of the drilling fluid enters the central hole of the water cap from the third radial flow channel, and a small part of the drilling fluid enters the central hole of the water cap from the second radial flow channel; when the water cap continues to rotate to the third radial flow channel not being connected with the first radial groove, most of the drilling fluid cannot enter the central hole of the water cap from the third radial flow channel, and a small part of the drilling fluid continues to enter the central hole of the water cap from the second radial flow channel, generating a water hammer effect at the first radial groove.

[0013] The transmission assembly is provided with an upper straightening bearing group, a thrust ball bearing group, a transmission upper housing; a second retaining ring, a transmission lower housing, a lower straightening bearing group and a transmission shaft; the upper straightening bearing group and the lower straightening bearing group are used to ensure that the transmission shaft rotates around the axis; the thrust ball bearing group is used to withstand axial force; the second retaining ring is supported between the inner rings of the thrust ball bearing group and the lower straightening bearing group, and rotates with the inner rings of the thrust ball bearing group and the lower straightening bearing group; the upper part of the transmission upper housing is threadedly connected to the lower part of the second pulse housing; the upper part of the transmission lower housing is threadedly connected to the lower part of the transmission upper housing; the upper part of the transmission shaft is threadedly connected to the lower part of the water cap; the lower part of the transmission shaft is connected to the drill bit. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a structural schematic diagram of the device of the present invention;

[0015] Figure 2 It is a schematic diagram of the structure of the hammer of the device of the present invention being located at the top dead center;

[0016] Figure 3 It is a structural schematic diagram of the hammer of the device of the present invention being located at the bottom dead center;

[0017] Figure 4 It is a structural schematic diagram of the second radial flow channel of the device of the present invention being connected to the first radial groove;

[0018] Figure 5 It is a schematic structural diagram of the second radial flow channel of the device of the present invention not being connected to the first radial groove.

[0019] In the figure: 1, bypass valve assembly; 11, bypass housing; 12, valve core; 13, first spring; 14, valve seat; 111, first central flow channel; 112, valve core center hole; 113, valve core side hole; 114, bypass side hole; 115, valve seat center hole; 2, first pulse assembly; 21, first pulse upper housing; 22, hammer; 23, second spring; 24, first pulse lower housing; 25, static valve; 26, moving valve; 27, moving valve seat; 28, anti-drop rod; 29, first retaining ring; 201, second central flow channel; 202, first stop; 203, first axial flow channel; 204, second axial flow channel; 205, second stop; 206, third stop; 207, static valve groove; 20 8. Moving valve groove; 209. First radial flow channel; 210. First shaft shoulder; 212. Fourth stop; 3. Motor assembly; 31. Motor housing; 32. Motor stator; 33. Motor rotor; 4. Universal shaft assembly; 41. Universal shaft housing; 42. Ball universal shaft assembly; 5. Second pulse assembly; 51. Second pulse housing; 52. Water cap; 501. Second radial flow channel; 502. Third radial flow channel; 503. Center hole of water cap; 6. Transmission assembly; 61. Upper centering bearing group; 62. Thrust ball bearing group; 63. Upper transmission housing; 64. Second retaining ring; 65. Lower transmission housing; 66. Lower centering bearing group; 67. Transmission shaft; 601. Third center flow channel; 7. First cavity.

[0020] Specific implementation method

[0021] In order to make the purpose, technical solution and advantages of the present invention clearer, the present invention is further described below in conjunction with the accompanying drawings. In the description of the present invention, it should be understood that the terms "upper", "lower", "front", "back", "left", "right", "top", "bottom", "inside", "outside", "end face" 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.

[0022] A multi-stage pulse oscillation screw, mainly composed of a bypass valve assembly 1, a first pulse assembly 2, a motor assembly 3, a universal shaft assembly 4, a second pulse assembly 5 and a transmission assembly 6; the bypass valve assembly 1 is used to control the flow direction of drilling fluid; the first pulse assembly 2 is placed above the motor assembly 3, and is used to convert the rotational mechanical energy of the motor assembly 3 into the pulse action and axial impact of the first pulse assembly 2; the motor assembly 3 is used to convert the liquid pressure energy of the drilling fluid into the mechanical energy of the motor rotor 33 rotation; the universal shaft assembly 4 is used to convert the eccentric rotation of the motor rotor 33 into a fixed axis rotation around the axis; the second pulse assembly 5 is placed below the universal shaft assembly 4, and is used to convert the rotational mechanical energy generated by the motor assembly 3 into the pulse action of the second pulse assembly 5; the transmission assembly 6 is used to transmit the mechanical energy generated by the motor assembly 3 to the drill bit.

[0023] As a preferred embodiment: the bypass valve assembly 1 is provided with a bypass housing 11, a valve core 12, a first spring 13 and a valve seat 14; the bypass housing 11 is provided with a first central flow channel 111 and a bypass side hole 114; the valve core 12 is provided with a valve core central hole 112 and a valve core side hole 113; the valve seat 14 is provided with a valve seat central hole 115; the first central flow channel 111, the valve core central hole 112 and the valve seat central hole 115 are always connected; the first spring 13 abuts between the valve core 12 and the valve seat 14; a sealing device is provided between the valve core 12, the valve seat 14 and the bypass housing 11; when the tool is in the state of drilling, the bypass valve assembly 1 is in the open state, and the drilling fluid can enter the environmental control from the bypass side hole 114; when the tool is in the working state, the bypass valve assembly 1 is in the closed state, and the drilling fluid enters the second central flow channel 201 from the first central flow channel 111, the valve core central hole 112 and the valve seat central hole 115.

[0024] As a preferred implementation scheme: the first pulse assembly 2 is provided with a first pulse upper housing 21, a hammer 22, a second spring 23, a first pulse lower housing 24, a static valve 25, a movable valve 26, a movable valve seat 27, an anti-drop rod 28 and a first retaining ring 29; the upper part of the first pulse upper housing 21 is threadedly connected with the lower part of the bypass housing 11; the upper part of the first pulse lower housing 24 is threadedly connected with the lower part of the first pulse upper housing 21; the first pulse upper housing 21 is provided with a second central flow channel 201 and a first stop 202; the hammer 22 is provided with a first axial flow channel 203, a second axial flow channel 204 and a second stop 205; the first axial flow channel 203 and the second central flow channel 201 are periodically interconnected; The second axial flow channel 204 is always connected with the second central flow channel 201; the number of the first axial flow channels 203 is 3 to 6; one end of the second spring 23 abuts against the bottom of the first pulse upper shell 21, and the other end abuts against the top of the second stop 205; the hammer 22 can slide axially along the first pulse upper shell 21, and the sliding stroke is 20 to 50 mm; the first pulse lower shell 24 is provided with a third stop 206, a static valve groove 207 and a fourth stop 212; the static valve 25 is installed in the static valve groove 207; the shape of the static valve groove 207 is square, hexagonal and octagonal; the movable valve seat 27 is provided with a movable valve groove 208 and a first radial flow channel 209; the movable valve 26 is installed on the movable valve The groove 208 is in the shape of a square, a hexagon and an octagon; the number of the first radial flow channels 209 is 3 to 6; the anti-drop rod 28 is provided with a first shaft shoulder 210; the bottom of the movable valve seat 27 abuts against the first shaft shoulder 210 and is connected to the top of the anti-drop rod 28 through threads; the first retaining ring 29 is provided with a third axial flow channel 211; the number of the third axial flow channels 211 is 3 to 6; the first retaining ring 29 abuts against the fourth abutment 212; a first cavity 7 is formed between the hammer 22 and the static valve 25; in particular: in the initial state, the hammer 22 abuts against the third abutment 206 under the action of the second spring 23; when the drilling fluid enters, the movable valve 26, the movable valve seat 27 and the anti-drop rod 28 rotate together with the motor rotor 33. When the movable valve 26 rotates to the point where the flow area of ​​the static valve 25 is the smallest, a water hammer effect is generated in the first cavity 7. At the same time, under the action of local high pressure, the hammer 22 is pushed upward to compress the second spring 23. When the hammer 22 moves upward to contact the second stop 202, the first axial flow channel 203 is not connected to the second central flow channel 201, the axial flow channel area is reduced, and a secondary water hammer effect is generated; when the movable valve 26 continues to rotate until the flow area with the static valve 25 is the largest, the first cavity 7 is in a low-pressure state, and the hammer 22 is accelerated downward to impact the first pulse lower shell 24 under the joint action of the second spring 23 and the pressure energy of the drilling fluid to generate an axial impact.

[0025] As a preferred implementation scheme; the motor assembly 3 is provided with a motor housing 31, a motor stator 32 and a motor rotor 33; the top of the motor housing 31 is threadedly connected to the bottom of the first pulse lower housing 24; the top of the motor rotor 33 is threadedly connected to the bottom of the anti-drop rod 28; when drilling fluid enters, the motor rotor 33 is pushed to rotate eccentrically under the action of the drilling fluid pressure difference.

[0026] As a preferred implementation scheme; the universal joint assembly 4 is provided with a universal joint housing 41 and a ball universal joint assembly 42; the upper part of the universal joint housing 41 is threadedly connected to the lower part of the motor housing 31; the upper part of the ball universal joint assembly 42 is threadedly connected to the lower part of the motor rotor 33; the eccentric rotation of the motor rotor 33 is converted into a fixed axis rotation around the axis center.

[0027] As a preferred implementation scheme; the second pulse assembly 5 is provided with a second pulse housing 51 and a water cap 52; the second pulse housing 51 is provided with a first radial groove 504; the water cap 52 is provided with a second radial flow channel 501, a third radial flow channel 502 and a water cap center hole 503; the second radial flow channel 501 and the third radial flow channel 502 are always connected with the water cap center hole 503; the third radial flow channel 502 is intermittently connected with the first radial groove 504; the number of the first radial grooves 504 is 2 to 4; the number of the second radial flow channels 501 is 3 to 6; the number of the third radial flow channels 502 is consistent with the number of the first radial grooves 504; the The flow area of ​​the three radial flow channels 502 is 2 to 5 times that of the second radial flow channel 501; in particular: when the water cap 52 is rotated to the third radial flow channel 502 and connected with the first radial groove 504, most of the drilling fluid enters the water cap center hole 503 from the third radial flow channel 502, and a small part of the drilling fluid enters the water cap center hole 503 from the second radial flow channel 501; when the water cap 52 continues to rotate until the third radial flow channel 502 is no longer connected with the first radial groove 504, most of the drilling fluid cannot enter the water cap center hole 503 from the third radial flow channel 502, and a small part of the drilling fluid continues to enter the water cap center hole 503 from the second radial flow channel 501, generating a water hammer effect at the first radial groove 504.

[0028] As a preferred implementation scheme; the transmission assembly 6 is provided with an upper straightening bearing group 61, a thrust ball bearing group 62, a transmission upper shell 63, a second retaining ring 64, a transmission lower shell 65, a lower straightening bearing group 66 and a transmission shaft 67; the upper straightening bearing group 61 and the lower straightening bearing group 66 are used to ensure that the transmission shaft 67 rotates around the axis; the thrust ball bearing group 62 is used to withstand axial force; the second retaining ring 64 is supported between the inner rings of the thrust ball bearing group 62 and the lower straightening bearing group 66, and rotates with the inner rings of the thrust ball bearing group 62 and the lower straightening bearing group 66; the upper part of the transmission upper shell 63 is threadedly connected to the lower part of the second pulse shell 51; the upper part of the transmission lower shell 65 is threadedly connected to the lower part of the transmission upper shell 63; the upper part of the transmission shaft 67 is threadedly connected to the lower part of the water cap 52; the lower part of the transmission shaft 67 is connected to the drill bit.

[0029] The above shows and describes the basic principles, main features and advantages of the present invention. Those skilled in the art should understand that the present invention is not limited to the above embodiments. The above embodiments and descriptions are only for explaining the principles of the present invention. Without departing from the spirit and scope of the present invention, the present invention may have various changes and improvements, which fall within the scope of the present invention. The scope of protection of the present invention is defined by the attached claims and their equivalents.

Claims

1. A multi-stage pulse oscillation screw, mainly composed of a bypass valve assembly (1), a first pulse assembly (2), a motor assembly (3), a universal shaft assembly (4), a second pulse assembly (5) and a transmission assembly (6); the bypass valve assembly (1) is used to control the flow direction of drilling fluid; the first pulse assembly (2) is arranged above the motor assembly (3) and is used to convert the rotational mechanical energy generated by the motor assembly (3) into the pulse action and axial impact of the first pulse assembly (2); the motor assembly (3) is used to convert the liquid pressure energy of the drilling fluid into the rotational mechanical energy of the motor rotor (33); the universal shaft assembly (4) is used to convert the eccentric rotation of the motor rotor (33) into the fixed axis rotation around the axis; the second pulse assembly (5) is arranged below the universal shaft assembly (4) and is used to convert the rotational mechanical energy generated by the motor assembly (3) into the pulse action of the second pulse assembly (5); the transmission assembly (6) is used to transmit the rotational mechanical energy generated by the motor assembly (3) to the drill bit; The first pulse assembly (2) is provided with a first pulse upper housing (21), a hammer (22), a second spring (23), a first pulse lower housing (24), a static valve (25), a movable valve (26), a movable valve seat (27), an anti-drop rod (28) and a first retaining ring (29); the first pulse upper housing (21) is provided with a second central flow channel (201) and a first stop (202); the hammer (22) is provided with a first axial flow channel (203), a second axial flow channel (204) and a second stop (205); the first axial flow channel (203) is periodically connected to the second central flow channel (201); the second axial flow channel (204) is provided with a first stop (205); 04) is always connected to the second central flow channel (201); one end of the second spring (23) abuts against the bottom of the first pulse upper shell (21), and the other end abuts against the top of the second stop (205); the first pulse lower shell (24) is provided with a third stop (206), a static valve groove (207) and a fourth stop (212); the static valve (25) is installed in the static valve groove (207); the dynamic valve seat (27) is provided with a dynamic valve groove (208) and a first radial flow channel (209); the dynamic valve (26) is installed in the dynamic valve groove (208); the anti-drop rod (28) is provided with a first shaft shoulder (210); the lower part of the dynamic valve seat (27) The first retaining ring (29) is provided with a third axial flow channel (211); the first retaining ring (29) is supported on a fourth support platform (212); a first cavity (7) is formed between the hammer (22) and the static valve (25); in the initial state, the hammer (22) is supported on the third support platform (206) under the action of the second spring (23); when drilling fluid enters, the movable valve (26), the movable valve seat (27) and the anti-drop rod (28) rotate together with the motor rotor (33); when the movable valve (26) rotates to the static valve (25) and the flow area is minimized, the movable valve (26 ... and the first retaining ring (29) is provided with a third axial flow channel (211); the first retaining ring (29) is supported on a fourth support platform (212); a first cavity (7) is formed between the hammer (22) and the static valve (25); in the initial state, the hammer (22) is supported on the third support platform (206) under the action of the second spring (23); when drilling fluid enters, the movable valve (26), the movable valve seat (27) and the anti-drop rod (28) rotate together with the motor rotor (33); when the movable valve (26) rotates to the static valve (25) and the flow area is minimized, the movable valve (26) and the static valve (25) rotate together with the motor rotor (33); and the first retaining ring (29) is provided with a third axial flow channel (211); the first retaining ring (29) is supported on a fourth support platform (212); When the moving valve (26) rotates to the maximum flow area with the static valve (25), the first cavity (7) is in a low pressure state. The moving valve (26) is accelerated to impact the first pulse lower housing (24) downwards under the combined action of the second spring (23) and the drilling fluid pressure energy to impact the first pulse lower housing (24) to generate an axial impact. The second pulse assembly (5) is provided with a secondary pulse housing (51) and a water cap (52); the secondary pulse housing (51) is provided with a first radial groove (504); the water cap (52) is provided with a second radial flow channel (501), a third radial flow channel (502) and a water cap center hole (503); the second radial flow channel (501) and the third radial flow channel (502) are always connected to the water cap center hole (503); the third radial flow channel (502) is intermittently connected to the first radial groove (504); when the water cap (52) is turned to the third radial flow channel (502) and the first radial groove When the groove (504) is connected, most of the drilling fluid enters the central hole (503) of the water cap from the third radial flow channel (502), and a small part of the drilling fluid enters the central hole (503) of the water cap from the second radial flow channel (501); when the water cap (52) continues to rotate until the third radial flow channel (502) is no longer connected to the first radial groove (504), most of the drilling fluid cannot enter the central hole (503) of the water cap from the third radial flow channel (502), and a small part of the drilling fluid continues to enter the central hole (503) of the water cap from the second radial flow channel (501), generating a water hammer effect at the first radial groove (504).

2. A multi-stage pulse oscillation screw according to claim 1, characterized in that: The hammer (22) periodically moves upward under the action of the water hammer to compress the second spring (23), and the stroke of the hammer (22) is 20-50 mm.

3. The multi-stage pulse oscillation screw according to claim 1, characterized in that: The hammer (22) is provided with a first axial flow channel (203), the first axial flow channel (203) being intermittently connected to the second central flow channel (201); the number of the first axial flow channels (203) is 3 to 6.

4. The multi-stage pulse oscillation screw according to claim 1, characterized in that: The first pulse lower housing (24) is provided with a static valve groove (207); the static valve groove (207) is in the shape of a square, a hexagon or an octagon; and the static valve (25) is installed in the static valve groove (207).

5. The multi-stage pulse oscillation screw according to claim 1, characterized in that: The movable valve seat (27) is provided with a movable valve groove (208) and a first radial flow channel (209); the movable valve groove (208) is in a square, hexagonal or octagonal shape; the number of the first radial flow channels (209) is 3 to 6; and the movable valve (26) is installed in the movable valve groove (208).

6. The multi-stage pulse oscillation screw according to claim 1, characterized in that: The static valve (25) and the dynamic valve (26) are provided with axial through holes. According to different working conditions, the size, number and position of the axial through holes can be arranged in various combinations, thereby achieving different pulse effects.

7. The multi-stage pulse oscillation screw according to claim 1, characterized in that: The water cap (52) is provided with a second radial flow channel (501), a third radial flow channel (502) and a water cap central hole (503); the second radial flow channel (501) is always connected to the first radial groove (504); the third radial flow channel (502) is intermittently connected to the first radial groove (504); the number of the second radial flow channels (501) is 3 to 6; the number of the third radial flow channels (502) is 2 to 4; and the flow channel area of ​​the third radial flow channel (502) is 2 to 5 times that of the second radial flow channel (501).

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