A shock absorber for drilling

Abstract

The present application relates to the technical fields of downhole drilling auxiliary tool, especially relates to a shock absorber for drilling, aiming at solving the problem of insufficient damping effect of the existing damping technology. The present application comprises a mandrel assembly, a flow limiting piston and a first return spring; a flow hole is formed on the mandrel assembly, and the flow limiting piston is inserted into the mandrel assembly; in the initial state, the flow limiting piston blocks the flow hole under the elastic force of the first return spring; the flow limiting piston can overcome the elastic force of the first return spring and move along the axial direction of the mandrel assembly under the pushing of the fluid, so as to open the flow hole. When the fluid with pressure pulsation passes through the flow channel inside the mandrel assembly, axial impact will be generated on the tool string; when the pressure is too high, the fluid pressure pushes the flow limiting piston to move downward, and the fluid enters the annulus through the flow hole, so as to reduce the fluid pressure inside the tool, realize the reduction of the pulsation impact of the axial fluid, and reduce the vibration.

Description

Technical Field

[0001] This invention relates to the field of downhole drilling auxiliary tools, and more particularly to a drilling vibration damper. Background Technology

[0002] With the development of oil and gas resources, shallow, easily exploitable resources are gradually being depleted, prompting the exploration and development field to focus on deep and ultra-deep wells. During deep and ultra-deep well drilling, complex geological conditions often lead to the encounter with hard formations and complex lithologies. Drilling through these formations is difficult and inefficient. Typically, when encountering hard or medium-hardness coarse-grained heterogeneous rock formations during drilling, the drill bit's rock-breaking efficiency decreases significantly, and the drill bit wear rate increases dramatically. Deep-seated rocks are hard, brittle, and have high static pressure resistance, thus requiring impact rock breaking. Existing vibration reduction technologies are insufficient, leading to reduced drill bit durability and efficiency. Summary of the Invention

[0003] The purpose of this invention is to provide a vibration damper for drilling, so as to solve the problem of insufficient vibration reduction effect of existing vibration reduction technology.

[0004] To solve the above-mentioned technical problems, the technical solution provided by the present invention is as follows:

[0005] A drilling vibration damper includes a mandrel assembly, a flow-limiting piston, and a first return spring; the mandrel assembly has a vent hole, and the flow-limiting piston is inserted into the mandrel assembly.

[0006] In the initial state, the flow-limiting piston blocks the drain hole under the elastic force of the first reset spring; the flow-limiting piston can overcome the elastic force of the first reset spring and move axially along the mandrel assembly under the push of fluid, thereby opening the drain hole.

[0007] Furthermore, the drilling vibration damper also includes a sleeve assembly, wherein the mandrel assembly is inserted into the sleeve assembly and screwed into the sleeve assembly;

[0008] The mandrel assembly is capable of moving along its own axis and rotating relative to the sleeve assembly.

[0009] Furthermore, the drilling damper also includes a second return spring, which is used to apply a thrust to the mandrel assembly in the same direction as the drilling.

[0010] Furthermore, the drilling damper also includes a throttle piston, and the spindle assembly includes a throttle valve disc;

[0011] The throttling piston is provided with a first flow channel hole, and the throttling valve disc is provided with a second flow channel hole;

[0012] The throttling piston rotates relative to the throttling valve disc to change the flow area of ​​the first flow channel orifice and the second flow channel orifice.

[0013] Furthermore, the drilling damper also includes a third return spring, the elastic force of which is used to push the throttle piston so that the throttle piston abuts against the throttle valve disc.

[0014] Furthermore, the drilling vibration damper also includes a first limiting nut, a second limiting nut, and a third limiting nut;

[0015] The first limiting nut is fitted onto the flow-limiting piston and threadedly connected to the flow-limiting piston. The first limiting nut can abut against the spindle assembly to limit the distance the first return spring drives the flow-limiting piston to move.

[0016] The second limiting nut is fitted onto the spindle assembly and threadedly connected to the spindle assembly. The second limiting nut can abut against the sleeve assembly to limit the distance the second return spring drives the spindle assembly to move.

[0017] The third limiting nut is fitted onto the throttling piston and threadedly connected to it. The third limiting nut can abut against the sleeve assembly to limit the distance the throttling piston moves due to the third return spring.

[0018] Furthermore, the sleeve assembly includes an upper connector, an upper housing, and a threaded housing connected in sequence; the mandrel assembly includes the throttle valve disc, a connecting mandrel, a threaded mandrel, and a lower connector connected in sequence.

[0019] The second return spring is fitted onto the connecting spindle, with one end abutting against the connecting spindle and the other end abutting against the upper housing;

[0020] The threaded housing is provided with internal threads, and the threaded mandrel is provided with external threads; the threaded mandrel is screwed into the threaded housing.

[0021] The flow-limiting piston is inserted into the lower connector, and one end of the first return spring abuts against the lower connector, while the other end abuts against the flow-limiting piston.

[0022] Furthermore, the threads on which the sleeve assembly and the mandrel assembly engage are multi-start threads.

[0023] Furthermore, the second return spring is configured as a disc spring.

[0024] Furthermore, a plurality of first flow channel holes are arranged around the axis of the throttling piston, and a plurality of second flow channel holes are arranged around the axis of the throttling valve disc.

[0025] In summary, the technical effects achieved by this invention are as follows:

[0026] The drilling vibration damper provided by the present invention includes a mandrel assembly, a flow-limiting piston, and a first return spring; a vent hole is provided on the mandrel assembly, and the flow-limiting piston is inserted into the mandrel assembly; in the initial state, the flow-limiting piston blocks the vent hole under the elastic force of the first return spring; the flow-limiting piston can overcome the elastic force of the first return spring and move axially along the mandrel assembly under the push of fluid, thereby opening the vent hole.

[0027] The drilling vibration damper provided by this invention reduces the impact of pressure-pulsating fluid through the arrangement of a first return spring and a vent hole. Specifically, when pressure-pulsating fluid flows through the internal channels of the mandrel assembly, it generates axial impact on the tool string. When the pressure is too high, the fluid pressure acts on the upper end face of the flow-limiting piston, thereby pushing the flow-limiting piston downward and allowing the fluid to enter the annulus through the vent hole, thus reducing the fluid pressure inside the tool and reducing the axial fluid pulsating impact, thereby mitigating vibration. When the pressure is normal, the first return spring pushes the flow-limiting piston to return to its original position to close the vent hole, ensuring normal operation of the drill bit. This improves the durability of the drill bit and ensures its rock-breaking efficiency. Attached Figure Description

[0028] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the structure of a drilling vibration damper provided in an embodiment of the present invention;

[0030] Figure 2 for Figure 1 Enlarged view of point A in the middle;

[0031] Figure 3 This is a schematic diagram of the throttle valve disc.

[0032] Figure 4 This is a schematic diagram of the throttling piston structure;

[0033] Figure 5 This is a schematic diagram of the threaded mandrel.

[0034] Icons: 100, mandrel assembly; 110, throttle valve disc; 120, connecting mandrel; 130, threaded mandrel; 140, lower connector; 101, vent hole; 102, second flow channel hole; 200, flow-limiting piston; 300, first return spring; 400, sleeve assembly; 410, upper connector; 420, upper housing; 430, threaded housing; 500, second return spring; 600, throttle piston; 601, first flow channel hole; 700, third return spring; 800, first limit nut; 900, second limit nut; 1000, third limit nut. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the invention without inventive effort are within the scope of protection of the invention.

[0037] The following detailed description of some embodiments of the present invention is provided in conjunction with the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0038] During drilling, when encountering hard or medium-hard coarse-grained heterogeneous rock formations, the drill bit's rock-breaking efficiency decreases significantly, and the drill bit wear rate increases dramatically. Deep underground rocks are hard, brittle, and have high static pressure resistance, thus requiring impact rock breaking. Existing vibration reduction technologies are insufficient, leading to reduced drill bit durability and efficiency.

[0039] In view of this, the present invention provides a drilling vibration damper, including a mandrel assembly 100, a flow-limiting piston 200, and a first return spring 300; a vent hole 101 is provided on the mandrel assembly 100, and the flow-limiting piston 200 is inserted into the mandrel assembly 100; in the initial state, the flow-limiting piston 200 blocks the vent hole 101 under the elastic force of the first return spring 300; the flow-limiting piston 200 can overcome the elastic force of the first return spring 300 and move axially along the mandrel assembly 100 under the push of fluid, thereby opening the vent hole 101.

[0040] The drilling vibration damper provided by this invention reduces the impact of fluid with pressure pulsation through the arrangement of a first return spring 300 and a vent hole 101. Specifically, when fluid with pressure pulsation flows through the flow channel inside the mandrel assembly 100, it generates an axial impact on the tool string. When the pressure is too high, the fluid pressure acts on the upper end face of the flow-limiting piston 200, thereby pushing the flow-limiting piston 200 downward and allowing the fluid to enter the annulus through the vent hole 101, thereby reducing the fluid pressure inside the tool, reducing the axial fluid pulsation impact, and mitigating vibration. When the pressure is normal, the first return spring 300 pushes the flow-limiting piston 200 to return to its original position to close the vent hole 101, ensuring the normal operation of the drill bit. This improves the durability of the drill bit and ensures its rock-breaking efficiency.

[0041] The following combination Figures 1-5 The structure and shape of the drilling vibration damper provided in this embodiment are described in detail below:

[0042] The drilling vibration damper provided in this embodiment includes a spindle assembly 100, a flow-limiting piston 200, a first return spring 300, a sleeve assembly 400, a second return spring 500, a throttle piston 600, a third return spring 700, a first limit nut 800, a second limit nut 900, and a third limit nut 1000. Figure 1 , Figure 2 As shown.

[0043] Specifically, the mandrel assembly 100 includes a throttle valve disc 110, a connecting mandrel 120, a threaded mandrel 130, and a lower connector 140 connected in sequence by threads, with the lower connector 140 connected to the drill bit; the sleeve assembly 400 includes an upper connector 410, an upper housing 420, and a threaded housing 430 connected in sequence by threads.

[0044] In this embodiment, the mandrel assembly 100 is inserted into the sleeve assembly 400, and the mandrel assembly 100 is provided with a power flow channel extending along its own axis for fluid passage. Specifically, the throttling piston 600 is inserted into the upper connector 410 and disposed above the throttling valve disc 110, the throttling valve disc 110 and the connecting mandrel 120 are inserted into the upper housing 420, the threaded mandrel 130 is inserted into the threaded housing 430 and screwed into the threaded housing 430, the lower connector 140 is disposed below the sleeve assembly 400, and the flow-limiting piston 200 is inserted into the lower connector 140.

[0045] The upper connector 410 has a third annular boss on its inner wall. A third return spring 700 is fitted onto the throttling piston 600, with one end abutting against the piston 600 and the other end abutting against the third annular boss. This spring applies a thrust to the throttling piston 600, causing it to abut against the throttling valve disc 110. A third limiting nut 1000 is fitted onto the throttling piston 600 and threadedly connected to it. The limiting nut 1000 is positioned above the third annular boss, thus abutting against it to limit the downward movement of the throttling piston 600 by the third return spring 700. This prevents the piston 600 from dislodging from the annular boss, and avoids deviation when the piston 600 moves upward, which could cause the upper end of the piston 600 to abut against the lower surface of the annular boss, affecting liquid flow and normal operation.

[0046] In this embodiment, the throttling piston 600 is provided with a first flow channel hole 601, and the throttling valve disc 110 is provided with a second flow channel hole 102, such as... Figure 3 , Figure 4 As shown. Specifically, the throttling piston 600 has four first flow channel holes 601 evenly distributed around its own axis, and the throttling valve disc 110 has four second flow channel holes 102 evenly distributed around its own axis. The throttling piston 600 and the throttling valve disc 110 can rotate relative to each other to change the flow area of ​​the first flow channel holes 601 and the second flow channel holes 102.

[0047] In this embodiment, a second annular boss is provided on the inner wall of the upper housing 420. A second return spring 500 is fitted onto the connecting mandrel 120, with one end abutting against the connecting mandrel 120 and the other end abutting against the second annular boss, used to apply a thrust to the connecting mandrel 120 to push it downwards. A second limiting nut 900 is fitted onto the connecting mandrel 120 and threadedly connected to it, and the second limiting nut 900 is positioned above the second annular boss, thereby abutting against the second annular boss to limit the distance the second return spring 500 pushes the connecting mandrel 120 downwards, preventing the threaded mandrel 130 from disengaging from the threaded housing 430. That is, the second return spring 500 is used to apply a thrust to the mandrel assembly 100 in the same direction as the drilling. Specifically, the second return spring 500 can be a disc spring, with multiple disc springs arranged axially, such as... Figure 2 As shown, it is used to provide sufficient thrust.

[0048] In this embodiment, the threaded housing 430 is provided with internal threads, and the threaded mandrel 130 is provided with external threads. The threaded mandrel 130 is screwed into the threaded housing 430. Specifically, the screwing threads of the two are multi-start threads to ensure that the two can rotate relative to each other, thereby realizing the axial movement of the threaded mandrel 130.

[0049] In this embodiment, the inner wall of the lower connector 140 is provided with a first annular boss. The first return spring 300 is fitted onto the flow-limiting piston 200, with one end abutting against the flow-limiting piston 200 and the other end abutting against the first annular boss, for applying an upward thrust to the flow-limiting piston 200. Specifically, the side wall of the lower connector 140 is provided with a radially extending vent hole 101, and the lower connector 140 and the flow-limiting piston 200 form a closed annular inner cavity. The annular inner cavity communicates with the vent hole 101 to isolate the fluid in the power flow channel and prevent the fluid from flowing out through the vent hole 101; at the same time, the first return spring 300 is disposed in the annular inner cavity. The first limiting nut 800 is fitted onto the flow-limiting piston 200 and threadedly connected to the flow-limiting piston 200. The first limiting nut 800 is located below the first annular boss, so that it can abut against the first annular boss to limit the distance that the first return spring 300 pushes the flow-limiting piston 200 to move upward, preventing the flow-limiting piston 200 from rising excessively and causing the annular inner cavity to connect with the power flow channel, thereby connecting the drain hole 101 with the power flow channel and causing the drain hole 101 to leak.

[0050] In the initial state, the first reset spring 300 causes the flow-limiting piston 200 to block the drain hole 101, thereby preventing fluid from flowing out through the drain hole 101.

[0051] The working process of the drilling vibration damper provided in this embodiment is as follows:

[0052] The fluid with pressure pulsation enters through the throttling piston 600 and flows sequentially through the first flow channel hole 601, the second flow channel hole 102, the connecting mandrel 120, the threaded mandrel 130, and the axial through hole of the flow limiting piston 200 before driving the drill bit to work.

[0053] When the fluid pressure is too high, the fluid pushes the flow-limiting piston 200 to move and compress the first return spring 300, so that some fluid flows out through the drain hole 101, reducing the fluid pressure inside the tool, reducing axial fluid pulsation impact, and ensuring the smooth operation of the drill bit.

[0054] When the drill bit is subjected to axial impact, the resistance is transmitted to the mandrel assembly 100, which in turn pushes the mandrel assembly 100 upward and causes relative rotation between the threaded mandrel 130 and the threaded housing 430. The threaded mandrel 130 spirals upward, at which point the second return spring 500 and the third return spring 700 are compressed. This means that the energy of the axial impact is absorbed by the second return spring 500 and the third return spring 700. This design allows the vibration damper to effectively absorb and disperse impact loads under different geological conditions and drilling depths.

[0055] As the mandrel assembly 100 spirals upwards axially, the throttle valve disc 110 rotates, causing a change in the cross-sectional area of ​​the first flow channel hole 601 and the second flow channel hole 102, thereby reducing the flow area. The reduced flow area increases fluid resistance, and the fluid pressure also acts on the throttle piston 600 and the throttle valve disc 110, further preventing the mandrel assembly 100 from rising. In other words, the fluid resistance and the disc spring work together to absorb the axial vibration impact energy.

[0056] When the axial impact of the drill bit decreases, the mandrel assembly 100 can be reset under the push of the second return spring 500 and the third return spring 700. At this time, the threaded mandrel 130 and the threaded housing 430 rotate in opposite directions and the mandrel assembly 100 moves downward.

[0057] When the drill bit gets stuck and its rotation is obstructed, the threaded mandrel 130 will rotate relative to the threaded housing 430 and rise along the helical surface of the thread, thus unscratching the drill bit and reducing radial vibration. This design improves the drill bit's adaptability under complex geological conditions and reduces the risk of stuck drill bits. It should be noted that the threaded mandrel 130 and the threaded housing 430 will not disengage.

[0058] The drilling vibration damper provided in this embodiment achieves effective vibration reduction during deep and ultra-deep well drilling through the combined effect of the above functions, improving the durability and efficiency of the drill bit, reducing drilling costs, and enhancing the adaptability and reliability of drilling equipment. It not only improves the success rate of drilling but also provides more efficient and reliable technical support for the development of resources such as oil, shale gas, and geothermal energy.

[0059] The drilling vibration damper provided in this embodiment utilizes the elastic deformation of a spring and the hydrodynamic effect of the vent hole 101. Through the synergistic effect of the spring and the vent hole 101, it effectively absorbs and disperses impact loads, significantly reducing drill bit vibration and thus improving drilling stability and speed. This vibration reduction effect not only extends the service life of the drill bit but also reduces the frequency of replacement, thereby lowering maintenance costs. Furthermore, it reduces the risk of drill bit damage and improves the safety of the drilling process, while also reducing material consumption and waste generation.

[0060] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A vibration damper for drilling, characterized in that, It includes a spindle assembly (100), a flow-limiting piston (200), and a first return spring (300); the spindle assembly (100) has a vent hole (101), and the flow-limiting piston (200) is inserted into the spindle assembly (100); In the initial state, the flow-limiting piston (200) blocks the drain hole (101) under the elastic force of the first return spring (300); the flow-limiting piston (200) can overcome the elastic force of the first return spring (300) and move along the axial direction of the mandrel assembly (100) under the push of fluid, thereby opening the drain hole (101).

2. The drilling vibration damper according to claim 1, characterized in that, It also includes a sleeve assembly (400), the mandrel assembly (100) being inserted into the sleeve assembly (400) and screwed into the sleeve assembly (400); The mandrel assembly (100) is capable of moving along its own axis and rotating relative to the sleeve assembly (400).

3. The drilling vibration damper according to claim 2, characterized in that, It also includes a second return spring (500) for applying a thrust to the mandrel assembly (100) in the same direction as the drilling.

4. The drilling vibration damper according to claim 3, characterized in that, It also includes a throttling piston (600), and the spindle assembly (100) includes a throttling valve disc (110); The throttling piston (600) is provided with a first flow channel hole (601), and the throttling valve disc (110) is provided with a second flow channel hole (102); The throttling piston (600) rotates relative to the throttling valve disc (110) to change the flow area of ​​the first flow channel hole (601) and the second flow channel hole (102).

5. The drilling vibration damper according to claim 4, characterized in that, It also includes a third return spring (700), the elastic force of which is used to push the throttle piston (600) so that the throttle piston (600) abuts against the throttle valve disc (110).

6. The drilling vibration damper according to claim 5, characterized in that, It also includes a first limiting nut (800), a second limiting nut (900), and a third limiting nut (1000); The first limiting nut (800) is fitted onto the flow limiting piston (200) and threadedly connected to the flow limiting piston (200). The first limiting nut (800) can abut against the spindle assembly (100) to limit the distance that the first return spring (300) drives the flow limiting piston (200) to move. The second limiting nut (900) is fitted onto the spindle assembly (100) and threadedly connected to the spindle assembly (100). The second limiting nut (900) can abut against the sleeve assembly (400) to limit the distance that the second return spring (500) can drive the spindle assembly (100) to move. The third limiting nut (1000) is fitted onto the throttle piston (600) and threadedly connected to the throttle piston (600). The third limiting nut (1000) can abut against the sleeve assembly (400) to limit the distance that the third return spring (700) can drive the throttle piston (600) to move.

7. The drilling vibration damper according to claim 6, characterized in that, The sleeve assembly (400) includes an upper connector (410), an upper housing (420), and a threaded housing (430) connected in sequence; the mandrel assembly (100) includes the throttle valve disc (110), a connecting mandrel (120), a threaded mandrel (130), and a lower connector (140) connected in sequence. The second return spring (500) is fitted onto the connecting spindle (120), with one end abutting against the connecting spindle (120) and the other end abutting against the upper housing (420); The threaded housing (430) is provided with internal threads, the threaded mandrel (130) is provided with external threads, and the threaded mandrel (130) is screwed into the threaded housing (430); The flow-limiting piston (200) is inserted into the lower connector (140), and one end of the first return spring (300) abuts against the lower connector (140) and the other end abuts against the flow-limiting piston (200).

8. The drilling vibration damper according to claim 2, characterized in that, The thread on which the sleeve assembly (400) and the mandrel assembly (100) engage is a multi-start thread.

9. The drilling vibration damper according to claim 3, characterized in that, The second return spring (500) is configured as a disc spring.

10. The drilling vibration damper according to claim 4, characterized in that, A plurality of first flow channel holes (601) are arranged around the axis of the throttling piston (600), and a plurality of second flow channel holes (102) are arranged around the axis of the throttling valve disc (110).

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