A multi-stage supercharging injection device and a drilling pipe string

Abstract

The application relates to a multi-stage supercharging injection device and a drilling pipe column, and belongs to the technical field of oil drilling. The multi-stage supercharging injection device and the drilling pipe column comprise a supercharging mechanism, the supercharging mechanism comprises a shell and a supercharging assembly arranged in the shell, a liquid inlet and a liquid outlet are formed in the shell, the supercharging assembly comprises an upper piston arranged at one end of the liquid inlet and used for liquid inlet supercharging, a lower piston arranged at one end of the liquid outlet and used for liquid outlet supercharging, a central shaft arranged between the upper piston and the lower piston, and a venturi tube type injection outlet. In the application, the structure of three times of supercharging arranged in the device can improve the injection kinetic energy of a drill bit, improve the efficiency of deep water surface layer injection drilling, and avoid the problems that the independent supercharging device arranged on the ground is too large in displacement, the injection motor is eroded, and the service life is reduced.

Description

Technical Field

[0001] This application relates to the field of oil drilling technology, and in particular to a multi-stage pressurized injection device and drilling string. Background Technology

[0002] In recent years, the exploration and development of oil and gas resources in deep water areas has gradually become a focus of common attention for the world's petroleum industry.

[0003] Due to the unique geological characteristics of deep ocean water, the shallow strata are soft mud layers with weak cementation and a tendency to collapse. At the same time, there are also complex factors such as shallow water flow and wind and waves that adversely affect drilling. Therefore, using conventional drilling methods during the drilling process can easily lead to problems such as oversized wellbore and wellbore collapse, thus bringing significant risks to drilling operations. Therefore, for the special strata of deep water shallow layers, jet drilling with casing can drill the wellbore and run the casing at the same time, which can better address this drilling challenge.

[0004] However, one of the challenges of jet drilling technology is to form a wellbore through jetting to facilitate the running of the guide pipe. However, the main way to achieve the jetting function in the present is through a large-displacement screw drill string with a drill bit. On the one hand, under the premise of a certain displacement, the hydraulic energy output by the motor will be limited to a certain extent, and the jetting effect will be affected to a certain extent. On the other hand, if the displacement is too large, it will cause erosion of the internal structure of the motor, reduce its service life, increase the number of tripping in and out of the hole, and have an adverse effect on drilling efficiency. Summary of the Invention

[0005] This application provides a multi-stage pressurized jetting device and drilling string to solve the problems in related technologies, such as insufficient jetting energy displacement resulting in poor erosion effect and excessive displacement causing jetting motor erosion and reduced lifespan.

[0006] The first aspect of this application provides a multi-stage pressurized injection device, comprising:

[0007] A pressurizing mechanism, comprising a housing and a pressurizing component disposed within the housing, wherein the housing has an inlet and an outlet.

[0008] The pressurization assembly includes an upper piston disposed at one end of the liquid inlet for pressurizing the liquid inlet, a lower piston disposed at one end of the liquid outlet for pressurizing the liquid outlet, and a central shaft disposed between the upper piston and the lower piston.

[0009] The housing has a drainage chamber, which allows the drilling fluid from the inlet to flow through the central shaft to the outlet, and creates a high pressure difference on both sides of the upper piston, causing the central shaft to reciprocate linearly within the housing for pressurization.

[0010] In some embodiments, a central channel is provided inside the central shaft, and an opening communicating with the central channel is provided on the side of the lower piston near the liquid outlet;

[0011] A central hole is provided on the side wall of the central shaft near the upper piston, which is connected to the central channel and the central hole is connected to the venting chamber.

[0012] In some embodiments, the housing includes an outer housing and an inner housing that are nested together.

[0013] The drain cavity is located between the inner shell and the outer shell, and is situated at one end of the liquid inlet of the shell.

[0014] The inner wall of the inner shell is provided with an upper drain port and a lower drain port that connect to the drain cavity, and the lower drain port is connected to the central hole.

[0015] In some embodiments, the upper piston moves between the upper drain port and the lower drain port.

[0016] In some embodiments, a stop block for limiting the lower piston is provided at one end of the liquid outlet of the inner shell.

[0017] In some embodiments, a straightening structure for maintaining its linear motion is fitted around the outer side of the central shaft.

[0018] In some embodiments, a boss is provided on the outer side of the central axis.

[0019] In some embodiments, a spring assembly is further provided on the outer side of the central shaft, the spring assembly being located below the boss body.

[0020] In some embodiments, the spring assembly includes a spring seat sleeved on the outside of the central shaft and a spring disposed within the spring seat and sleeved on the outside of the central shaft.

[0021] A second aspect of this application provides a drilling string that uses a multi-stage pressurized injection device, comprising:

[0022] The drill pipe body has an outlet end that can be inserted into the inlet of the housing in the pressurization mechanism and threadedly connected.

[0023] The beneficial effects of the technical solution provided in this application include:

[0024] The upper piston pressurizes the drilling fluid during its flow at the outlet, improving the efficiency of the drilling fluid flow and allowing it to circulate quickly, thus increasing the flow rate.

[0025] By using the lower piston to provide injection booster to the drilling fluid just before it is to be ejected, a second pressurization is achieved, increasing the pressure of the drilling fluid during injection so that sufficient pressure is maintained for the drilling fluid to be ejected.

[0026] By increasing the fluid velocity at the outlet through a venturi tube channel, a positive pressure differential is created at the outlet in the direction of inflow and outflow, allowing the pressurized drilling fluid to enter the drill bit water hole more efficiently.

[0027] The device's internal triple-pressurization structure increases the drill bit's jetting kinetic energy, improving the efficiency of surface jetting drilling in seepage areas. It also avoids the problem of excessive displacement caused by a separate pressurization device on the surface, which could lead to erosion of the jetting motor and reduced lifespan. This increases jetting energy and hydraulic energy at the drill bit's water inlet, thereby increasing the jetting kinetic energy against soft mudstone in deep water. This results in better formation of the wellbore and subsequent guide pipe, contributing to improved efficiency in deep-water surface drilling.

[0028] During the pressurization process of the upper and lower pistons, when the pressure decreases and the drilling fluid entering the outlet position drops to a certain level, the spring force and the hydraulic pressure at the lower end faces of the lower and upper pistons cause the central shaft to rise back. This causes the upper piston to squeeze the drilling fluid in the upper end face cavity, accelerating its passage through the drain chamber into the lower end face cavity of the upper piston. This allows the downward pressure of the upper and lower pistons to be maintained, continuing to supply new drilling fluid, thus continuing pressurization and maintaining the drilling fluid volume at the outlet. This enables the device to achieve automatic pressurization and automatic return to its original position, ensuring continuous pressurization efficiency and improving the device's working efficiency.

[0029] This device enables continuous pressurization, improving pressurization efficiency, and can automatically reset to maintain pressurization efficiency. It achieves downhole pulse pressurization, avoiding the need for independent pressurization devices on the surface, which increases costs, makes the device prone to damage and inconvenient to maintain, and also avoids the problem of excessive jetting volume from surface pressurization devices causing erosion of the motor's internal structure, reducing its service life, increasing the number of trips, and adversely affecting drilling efficiency. It also avoids the problem of insufficient jetting volume and poor jetting efficiency caused by the absence of a pressurization device. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 This is a schematic diagram of the structure provided for an embodiment of this application;

[0032] Figure 2 A bottom view of the lower piston and inner housing provided in an embodiment of this application;

[0033] Figure 3 This is a cross-sectional schematic diagram of the central shaft and central hole in the embodiments of this application.

[0034] 1. Drill pipe body; 3. Inner shell; 4. Lower drain port; 6. Central shaft; 7. Spring seat; 8. Central channel; 10. Venturi tube channel; 11. Stop block; 12. Spring; 13. Boss body; 14. Straightening structure; 15. Central hole; 16. Upper piston; 17. Upper drain port; 18. Liquid outlet; 19. Lower piston; 22. Outer shell; 23. Drain chamber. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0036] This application provides a multi-stage pressurized jetting device and drilling string, which can solve the problems in existing jetting drilling where insufficient jetting energy displacement leads to poor erosion effect and excessive displacement causes jetting motor erosion and reduced lifespan.

[0037] See Figure 1-3 As shown, the first aspect of this application provides a multi-stage pressurized injection device, comprising:

[0038] The pressurization mechanism includes a housing and a pressurization component disposed within the housing. The housing has an inlet and an outlet. The pressurization component includes an upper piston 16 disposed at one end of the inlet for pressurizing the inlet, a lower piston 19 disposed at one end of the outlet for pressurizing the outlet, and a central shaft 6 disposed between the upper piston 16 and the lower piston 19. A venting chamber 23 is disposed within the housing. The venting chamber 23 is used to allow the drilling fluid from the inlet to flow through the central shaft 6 to the outlet, and to create a high pressure difference on both sides of the upper piston 16, causing the central shaft 6 to reciprocate linearly within the housing for pressurization.

[0039] The pressurization mechanism is in a vertical position during use, with one end of the inlet facing upwards and one end of the outlet facing downwards. The end of the upper piston 16 facing the inlet is the upper end face, and the end facing the outlet is the lower end face. When the drilling fluid enters the housing through the inlet, the drilling fluid is located in the cavity between the upper end face of the upper piston 16 and the housing. Then, through the discharge chamber 23, the drilling fluid located in the cavity of the upper end face of the upper piston 16 flows to the cavity between the lower end face of the upper piston 16 and the housing. Then, it flows out from the opening of the lower piston 19 through the central shaft 6, and finally is ejected from the outlet.

[0040] When drilling fluid enters the cavity formed between the upper end face of the upper piston 16 and the housing, some of the drilling fluid flows from the upper drain port 17 on the inner housing 3 into the drain chamber 23, and then from the drain chamber 23 through the lower drain port 4 into the cavity of the lower end face of the lower piston 19. Because the drain chamber 23 is narrow, the flow velocity at the lower drain port 4 is high when the drilling fluid enters the cavity of the lower end face of the lower piston 19, resulting in a decrease in pressure in the cavity where the lower end face of the upper piston 16 is located. This causes pressure to rise at both the upper and lower ends of the upper piston 16. A positive pressure difference is formed between the cavities on the surface, making the pressure in the cavity at the upper end of the upper piston 16 greater than the pressure in the cavity at the lower end of the upper piston 16. Under the combined action of the pressure difference and the fluid force in the cavity at the upper end of the upper piston 16, the upper piston 16 will move downward and drive the central shaft 6 downward. Then, the volume space of the cavity at the lower end of the upper piston 16 is gradually compressed, and the pressure inside the cavity gradually increases. The pressurized drilling fluid enters the central channel 8 from the central hole 15 on the outer wall of the central shaft 6, thus completing the first pressurization.

[0041] Next, the drilling fluid reaches the cavity at the lower end face of the lower piston 19. At this time, the central shaft 6 is moving downward, and the lower piston 19 is also moving downward. The lower piston 19 will squeeze the drilling fluid in the cavity at its lower end face. The volume space between the lower end face and the inner shell 3 gradually decreases, and the pressure in the cavity gradually increases, achieving a second pressurization, so that the drilling fluid in the cavity enters the outlet and is ejected.

[0042] The casing has a Venturi tube-type channel 10 inside the outlet. When the pressurized drilling fluid enters through the nozzle formed by the Venturi tube-type channel 10, the pressure near the outlet area decreases due to the high flow velocity at the nozzle outlet. Therefore, a positive pressure difference is formed between the cavity at the lower end face of the lower piston 19 and the nozzle outlet, which is more conducive to the pressurized drilling fluid entering the Venturi tube-type channel 10, thereby better increasing the injection pressure at the outlet and making the pressurized drilling fluid enter the drill bit water hole more efficiently.

[0043] By repeatedly pressurizing, the jet pressure at the outlet is increased, which avoids the poor erosion effect caused by insufficient jet energy displacement, and also avoids the problem of excessive displacement caused by setting up an independent pressurization device, which would lead to erosion of the jet motor and a reduction in its lifespan.

[0044] In some alternative embodiments, see Figure 1 and Figure 3 As shown, in this multi-stage pressurized injection device, a central channel 8 is provided inside the central shaft 6, and an opening communicating with the central channel 8 is provided on the side of the lower piston 19 near the liquid outlet. A central hole 15 communicating with the central channel 8 is provided on the side wall of the central shaft 6 near the upper piston 16, and the central hole 15 is connected to the discharge chamber 23.

[0045] A positive pressure difference is formed between the cavities of the upper and lower end faces of the upper piston 16, causing the upper piston 16 to move downward and drive the central shaft 6 downward. Then, the volume space of the cavity of the lower end face of the upper piston 16 is gradually compressed, and the pressure inside the cavity gradually increases. The pressurized drilling fluid enters the central channel 8 through the central hole 15 on the outer wall of the central shaft 6, and then enters the cavity of the lower end face of the lower piston 19 through the opening of the lower piston 19.

[0046] There are several central holes 15, and these central holes 15 are arranged in a ring at equal intervals around the central channel 8.

[0047] In some alternative embodiments, see Figure 1 As shown, in this multi-stage pressurized injection device, the housing includes an outer housing 22 and an inner housing 3 that are nested together. The drain cavity 23 is located between the inner housing 3 and the outer housing 22 and is located at one end of the liquid inlet of the housing. The inner wall of the inner housing 3 is provided with an upper drain port 17 and a lower drain port 4 that communicate with the drain cavity 23. The lower drain port 4 communicates with the central hole 15.

[0048] In this embodiment, the upper piston 16 moves between the upper drain port 17 and the lower drain port 4. The upper piston 16 is located between the upper drain port 17 and the lower drain port 4. When the central shaft 6 moves up and down, driving the upper piston 16 to move, the movement of the upper piston 16 forms the distance between the upper drain port 17 and the lower drain port 4, thus preventing the upper piston 16 from becoming too long and blocking the upper drain port 17 and the lower drain port 4. At the same time, when the upper piston 16 is close to the lower drain port 4, the downward pressure of the upper piston 16 will be less than the upward force of the upper piston 16, and the upper piston 16 will move upward, which can also prevent the upper piston 16 from blocking the lower drain port 4. Similarly, when the upper piston 16 is close to the upper drain port 17, the upward force of the upper piston 16 will be less than the downward pressure of the upper piston 16, and the upper piston 16 will move downward, which can prevent the upper piston 16 from blocking the upper drain port 17.

[0049] The outer shell 22 and inner shell 3, which are configured with an inner and outer casing, allow for the opening of a drainage cavity 23 within the shell. This allows the device itself to generate the driving force for the up-and-down movement of the central shaft 6, as well as the pressure from multiple pressurizations of the drilling fluid. After the drilling fluid enters the cavity formed between the upper end face of the upper piston 16 and the shell, some of the drilling fluid flows from the upper drainage port 17 on the inner shell 3 into the drainage cavity 23. Then, it flows from the drainage cavity 23 through the lower drainage port 4 into the cavity at the lower end face of the lower piston 19. Due to the narrowness of the drainage cavity 23, the flow rate at the lower drainage port 4 is relatively low when the drilling fluid enters the cavity at the lower end face of the lower piston 19. The pressure in the cavity at the lower end of the upper piston 16 decreases, creating a positive pressure difference between the cavities at the upper and lower ends of the upper piston 16. This makes the pressure in the cavity at the upper end of the upper piston 16 greater than the pressure in the cavity at the lower end of the upper piston 16. Under the combined action of the pressure difference and the fluid force in the cavity at the upper end of the upper piston 16, the upper piston 16 moves downward and drives the central shaft 6 downward. This gradually compresses the volume of the cavity at the lower end of the upper piston 16, causing the pressure inside the cavity to gradually increase. The pressurized drilling fluid then enters the central channel 8 through the central hole 15 on the outer wall of the central shaft 6.

[0050] In some alternative embodiments, see Figure 1 and Figure 2 As shown, in this multi-stage pressurized injection device, a stop block 11 for limiting the lower piston 19 is provided at one end of the liquid outlet of the inner housing 3. The stop block 11 prevents the lower piston 19 from falling too low and colliding with the housing, which would damage the device. At the same time, it prevents the lower central shaft 6 from falling too low and blocking the lower drain port 4, which would prevent it from reciprocating.

[0051] In some alternative embodiments, see Figure 1 As shown, in this multi-stage pressurized injection device, a straightening structure 14 is sleeved on the outer side of the central shaft 6 to maintain its linear motion. The straightening structure 14 can keep the central shaft 6 in a linear motion when it is reciprocating, and prevent the central shaft 6 from being indefinitely positioned, deflecting when moving up and down, which would cause it to be unable to move or the internal space to be destroyed, thus preventing the generation of a high pressure differential.

[0052] In some alternative embodiments, see Figure 1 As shown, in this multi-stage pressurized injection device, a boss 13 is provided on the outer side of the central shaft 6, and the boss 13 is fixedly connected to the outer side of the central shaft 6.

[0053] In this embodiment, a spring assembly is also provided on the outer side of the central shaft 6, and the spring assembly is located below the boss body 13.

[0054] In this embodiment, the spring assembly includes a spring seat 7 sleeved on the outside of the central shaft 6 and a spring 12 disposed inside the spring seat 7 and sleeved on the outside of the central shaft 6. The cross-section of the spring seat 7 is U-shaped. The spring seat 7 is fixedly connected to the inner wall of the inner housing 3. One end of the opening of the spring seat 7 faces the boss body 13. The spring 12 is disposed inside the spring seat 7 and sleeved on the outside of the central shaft 6.

[0055] When the central shaft 6 moves downward, the boss 13 will touch the spring 12. As the central shaft 6 continues to move downward, the boss 13 will continue to press down on the spring 12. As the central shaft 6 continues to move downward, the cavities at the lower end faces of the lower piston 19 and the upper piston 16 will gradually decrease, while the cavity at the upper end face of the upper piston 16 will gradually increase. The fluid pressure in the cavity at the upper end face of the upper piston 16 will decrease. The fluid pressure at the lower end face of the lower piston 19, the elastic force of the spring 12, and the fluid pressure at the lower end face of the upper piston 16 will all contribute to the overall dynamic balance. When the sum of the body pressures exceeds the fluid pressure in the cavity at the upper end of the upper piston 16, the central shaft 6 will move in the opposite direction, moving upwards until the fluid pressure in the cavity at the upper end of the upper piston 16 exceeds the sum of the fluid pressure at the lower end of the lower piston 19, the elastic force of the spring 12, and the fluid pressure at the lower end of the upper piston 16. Then, the central shaft 6 will continue to move downwards, thus achieving automatic reciprocating motion to provide periodic injection pressure for the drill bit, improving working efficiency, pressurization efficiency, and injection efficiency.

[0056] See Figure 1-3 As shown, a second aspect of this application provides a drilling string, including:

[0057] The drill pipe body 1 has a fluid outlet channel inside it. One end of the drill pipe body 1 has a fluid outlet hole 18 that connects to the fluid outlet channel. The end of the drill pipe body 1 with the fluid outlet hole 18 is inserted into the fluid inlet of the housing in the pressurization mechanism and threadedly connected. The drill pipe body 1 inputs drilling fluid into the housing through the fluid outlet hole 18.

[0058] The threaded connection between the drill pipe body 1 and the shell allows the multi-stage pressurized injection device to be quickly connected to the drill pipe body 1, pressurizing and injecting drilling fluid into the drill pipe body 1. It can also be quickly disassembled, repaired, replaced, and cleaned during disassembly, maintenance, and cleaning.

[0059] The working principle and process of this application:

[0060] When drilling fluid enters the cavity formed between the upper end face of the upper piston 16 and the housing, some of the drilling fluid flows from the upper drain port 17 on the inner housing 3 into the drain chamber 23, and then from the drain chamber 23 through the lower drain port 4 into the cavity of the lower end face of the lower piston 19. Because the drain chamber 23 is narrow, the flow velocity at the lower drain port 4 is high when the drilling fluid enters the cavity of the lower end face of the lower piston 19, resulting in a decrease in pressure in the cavity where the lower end face of the upper piston 16 is located. This causes pressure to rise at both the upper and lower end faces of the upper piston 16. A positive pressure difference is formed between the cavities, making the pressure in the cavity at the upper end of the upper piston 16 greater than the pressure in the cavity at the lower end of the upper piston 16. Under the combined action of the pressure difference and the fluid force in the cavity at the upper end of the upper piston 16, the upper piston 16 will move downward and drive the central shaft 6 downward. Then, the volume space of the cavity at the lower end of the upper piston 16 is gradually compressed, and the pressure inside the cavity gradually increases. The pressurized drilling fluid enters the central channel 8 from the central hole 15 on the outer wall of the central shaft 6, thus completing the first pressurization.

[0061] Next, the drilling fluid reaches the cavity at the lower end face of the lower piston 19. At this time, the central shaft 6 is moving downward, and the lower piston 19 is also moving downward. The lower piston 19 will squeeze the drilling fluid in the cavity at its lower end face. The volume space between the lower end face and the inner shell 3 gradually decreases, and the pressure in the cavity gradually increases, achieving a second pressurization, so that the drilling fluid in the cavity enters the outlet and is ejected.

[0062] The outlet of the casing is provided with a Venturi tube-type channel 10. When the pressurized drilling fluid enters through the nozzle formed by the Venturi tube-type channel 10, the pressure near the outlet area is reduced due to the high flow velocity at the nozzle outlet. Therefore, a positive pressure difference is also formed between the cavity at the lower end face of the lower piston 19 and the nozzle outlet, which is more conducive to the pressurized drilling fluid entering the Venturi tube-type channel 10, thereby better increasing the injection pressure at the outlet.

[0063] When the central shaft 6 moves downward, the boss 13 will touch the spring 12. As the central shaft 6 continues to move downward, the boss 13 will continue to press down on the spring 12. As the central shaft 6 continues to move downward, the cavities at the lower end faces of the lower piston 19 and the upper piston 16 will gradually decrease, while the cavity at the upper end face of the upper piston 16 will gradually increase. The fluid pressure in the cavity at the upper end face of the upper piston 16 will decrease. The fluid pressure at the lower end face of the lower piston 19, the elastic force of the spring 12, and the fluid pressure at the lower end face of the upper piston 16 will all contribute to the overall dynamic balance. When the sum of the body pressures exceeds the fluid pressure in the cavity at the upper end of the upper piston 16, the central shaft 6 will move in the opposite direction, moving upwards until the fluid pressure in the cavity at the upper end of the upper piston 16 exceeds the sum of the fluid pressure at the lower end of the lower piston 19, the elastic force of the spring 12, and the fluid pressure at the lower end of the upper piston 16. Then, the central shaft 6 will continue to move downwards, thus achieving automatic reciprocating motion to provide periodic injection pressure for the drill bit, improving working efficiency, pressurization efficiency, and injection efficiency.

[0064] In the description of this application, it should be noted that the terms "upper," "lower," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application 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, and therefore should not be construed as a limitation of this application. Unless otherwise expressly specified and limited, the terms "installed," "connected," and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication between two elements. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0065] It should be noted that in this application, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims

1. A multi-stage pressurized injection device, characterized in that, include: A pressurizing mechanism, comprising a housing and a pressurizing component disposed within the housing, wherein the housing has an inlet and an outlet. The pressurization assembly includes an upper piston (16) disposed at one end of the inlet for pressurizing the inlet, a lower piston (19) disposed at one end of the outlet for pressurizing the outlet, a central shaft (6) disposed between the upper piston (16) and the lower piston (19), and a venturi tube-type injection outlet. The housing is provided with a drain chamber (23), which is used to allow the drilling fluid in the inlet to flow through the central shaft (6) to the outlet, and to create a high pressure difference on both sides of the upper piston (16) so that the central shaft (6) can reciprocate linearly within the housing to pressurize it; A boss (13) is provided on the outer side of the central shaft (6); a spring assembly is also provided on the outer side of the central shaft (6), the spring assembly being located below the boss (13); the spring assembly includes a spring seat (7) sleeved on the outer side of the central shaft (6) and a spring (12) disposed in the spring seat (7) and sleeved on the outer side of the central shaft (6).

2. The multi-stage pressurized injection device as described in claim 1, characterized in that: The central shaft (6) has a central channel (8) inside, and the lower piston (19) has an opening that connects to the central channel (8) on the side near the liquid outlet. The central shaft (6) has a central hole (15) on the side wall near the upper piston (16) that connects to the central channel (8), and the central hole (15) is connected to the venting chamber (23).

3. The multi-stage pressurized injection device as described in claim 2, characterized in that: The housing includes an outer housing (22) and an inner housing (3) that are nested together. The drain cavity (23) is located between the inner shell (3) and the outer shell (22), and is located at one end of the liquid inlet of the shell; The inner wall of the inner shell (3) is provided with an upper drain port (17) and a lower drain port (4) that connect to the drain cavity (23), and the lower drain port (4) is connected to the central hole (15).

4. The multi-stage pressurized injection device as described in claim 3, characterized in that: The upper piston (16) moves between the upper drain port (17) and the lower drain port (4).

5. The multi-stage pressurized injection device as described in claim 3, characterized in that: The inner shell (3) is provided with a stop block (11) for the limiting lower piston (19) at one end of the liquid outlet.

6. The multi-stage pressurized injection device as described in claim 1, characterized in that: The outer side of the central shaft (6) is fitted with a straightening structure (14) for maintaining its linear motion.

7. A drilling string, wherein the drilling string uses the multi-stage pressurized injection device as described in any one of claims 1-6, characterized in that, include: The drill pipe body (1) has a liquid outlet channel inside. One end of the drill pipe body (1) has a liquid outlet hole (18) that connects to the liquid outlet channel. The end of the drill pipe body (1) with the liquid outlet hole (18) is inserted into the liquid inlet of the housing in the pressurizing mechanism and threadedly connected.

Images