Drilling tool and method

Abstract

The application provides a drilling tool internal blowout preventer and method. The drilling tool internal blowout preventer comprises a valve body having a hollow flow channel extending in an axial direction; a valve core arranged in the hollow flow channel and sealingly connected with an inner wall of the valve body, the valve core having a hollow cavity in communication with the hollow flow channel, the valve core comprising a partition plate separating the hollow cavity into a first hollow cavity and a second hollow cavity, the partition plate being provided with a first central through hole, and a lower end surface of the valve core being provided with a second central through hole; a baffle plate arranged in the second hollow cavity, one end of the baffle plate being reversibly connected with a side wall of the valve core; the baffle plate having an initial state and a blocking state, in the initial state, the baffle plate is arranged at an acute angle with the partition plate to avoid the first central through hole; when overflow or blowout occurs, the drilling fluid drives the baffle plate to reverse in a direction close to the partition plate and block the first central through hole, and the baffle plate is switched from the initial state to the blocking state. The application solves the problem that the drilling tool internal blowout preventer is prone to failure in the prior art.

Description

Technical Field

[0001] This invention relates to the field of petroleum exploration technology, and more specifically, to a blowout prevention tool and method for drill bits. Background Technology

[0002] During drilling, if fluid overflows such as brine or oil / gas / nitrogen drilling may occur downhole, the drill string assembly near the drill bit must be equipped with a float valve or arrow-shaped check valve to prevent drilling fluid from flowing back into the drill bit or drill string, causing accidents such as blowouts inside the drill string.

[0003] Currently, the main types of blowout preventers (BOPs) used near the drill bit in downhole drilling tools are plate-type float valves and arrow-shaped check valves. These valves are deployed into the well. During drilling or workover, if a blowout, kick, or cessation of positive circulation occurs, the arrow-shaped check valve quickly closes under the pressure of reverse circulation and spring force within the drill string, cutting off the internal flow and preventing blowout. Plate-type float valves rely on non-metallic sealing parts and a spring-controlled valve plate for sealing. During use, inspections after tripping the drill string often reveal spring breakage or softening, or failure of the non-metallic sealing parts, resulting in a failure rate exceeding 95%. In the event of a blowout, well control cannot be guaranteed. Arrow-shaped check valves also rely on the one-way sealing principle of a spring and a cone valve to prevent blowout. During use, inspections after tripping the drill string frequently reveal spring breakage or softening, failure to rebound, and a sealing failure rate also exceeding 95%.

[0004] Furthermore, during the drilling process, since the valve core is in a normally closed state, as the drilling depth increases, the pressure inside and outside the liquid column increases, which can cause the valve core to fail to varying degrees. After drilling to a certain depth, it is necessary to stop and fill the drilling fluid in the water hole of the drill string, which wastes a lot of non-productive time.

[0005] As can be seen from the above, the existing technology has the problem that the blowout preventer tools inside the drill bit are prone to failure. Summary of the Invention

[0006] The main objective of this invention is to provide a blowout preventer tool and method for drill bits, so as to solve the problem that blowout preventers for drill bits are prone to failure in the prior art.

[0007] To achieve the above objectives, according to one aspect of the present invention, a blowout preventer for drill bits is provided, comprising: a valve body having a hollow flow channel extending axially; a valve core disposed within the hollow flow channel and sealed to the inner wall of the valve body, the valve core having a hollow cavity communicating with the hollow flow channel, the valve core including a partition plate dividing the hollow cavity into a first hollow cavity and a second hollow cavity, the partition plate having a first central through hole, and the lower end face of the valve core having a second central through hole; a baffle plate disposed within the second hollow cavity, one end of the baffle plate being rotatably connected to the side wall of the valve core; the baffle plate having an initial state and a blocking state, wherein in the initial state, the baffle plate is disposed at an acute angle to the partition plate to avoid the first central through hole; when overflow or blowout occurs, drilling fluid enters the hollow cavity from the hollow flow channel and moves upward, the drilling fluid causing the baffle plate to flip along the direction close to the partition plate and block the first central through hole, the baffle plate switching from the initial state to the blocking state.

[0008] Furthermore, the blowout preventer inside the drill bit also includes a stop, which is set on the lower end face of the valve core and located on the side of the second central through hole near the baffle. In the initial state, the stop and the other end of the baffle form a limiting stop.

[0009] Furthermore, the blowout preventer inside the drill bit also includes a reset component, which is located at the connection between one end of the baffle and the side wall of the valve core, and is used to provide preload between the baffle and the stop component.

[0010] Furthermore, an overflow activation hole is provided on the lower end face of the valve core. The overflow activation hole is spaced apart from the second central through hole and located on the side close to the baffle.

[0011] Furthermore, the overflow activation hole is funnel-shaped with its diameter gradually decreasing along the direction toward the partition.

[0012] Furthermore, the sealing surface of the baffle is an outwardly convex curved surface, and the shape of the first central through hole is adapted to the sealing surface of the baffle.

[0013] Furthermore, the baffle is provided with a pressure measuring hole that penetrates the baffle axially.

[0014] Furthermore, the blowout preventer inside the drill bit also includes a seal, which includes: a first seal; a second seal, the first and second seals being spaced apart and disposed on the outer surface of the upper end of the valve core; and a third seal, the third seal being disposed on the outer surface of the lower end of the valve core.

[0015] Furthermore, the baffle is made of metal; and / or the baffle is made of the same material as the valve core.

[0016] Furthermore, both ends of the valve body are equipped with threads for connection to the drill bit.

[0017] According to another aspect of the present invention, a method for preventing blowout within a drill string is provided, wherein the blowout prevention method is implemented using the aforementioned internal blowout prevention tool. The blowout prevention method includes: limiting and stopping the baffle and stop of the internal blowout prevention tool; connecting the internal blowout prevention tool to the drill string and lowering them together into the well; in the event of overflow or blowout, drilling fluid backflows into the hollow cavity of the internal blowout prevention tool, causing the baffle to flip and block the first central through hole of the internal blowout prevention tool, thus preventing the drilling fluid from flowing upward; measuring the bottom hole pressure through the pressure measuring hole of the internal blowout prevention tool; and during tripping, the baffle naturally falls back to avoid the first central through hole, allowing the drilling fluid inside the internal blowout prevention tool to flow back into the well.

[0018] The technical solution of this invention provides a blowout preventer tool for drill bits, comprising a valve body, a valve core, and a baffle. The valve body has a hollow flow channel extending axially. The valve core is disposed within the hollow flow channel and is sealed to the inner wall of the valve body. The valve core has a hollow cavity communicating with the hollow flow channel. The valve core includes a partition that divides the hollow cavity into a first hollow cavity and a second hollow cavity. The partition has a first central through-hole, and the lower end face of the valve core has a second central through-hole. The baffle is disposed within the second hollow cavity, with one end of the baffle rotatably connected to the side wall of the valve core. The baffle has an initial state and a blocked state. In the initial state, the baffle and the partition are positioned at an acute angle to avoid the first central through-hole. In the event of overflow or blowout, drilling fluid flows from the hollow cavity... The drilling fluid enters the hollow cavity and moves upward. The drilling fluid drives the baffle to flip along the direction close to the partition and seal the first central through hole. The baffle switches from the initial state to the sealed state. In this way, when no overflow or blowout occurs, the baffle always avoids the first central through hole, thereby avoiding the impact of drilling fluid on the baffle. The baffle will only be impacted by drilling fluid and flipped upward when overflow or blowout occurs, thereby sealing the first central through hole to prevent the overflow from developing further. The above configuration prevents the baffle from repeatedly flipping under the impact of fluid in the drill string, thereby greatly reducing wear and fatigue, improving service life, and ensuring the long-term effectiveness of the blowout preventer in the drill string. This solves the problem of easy failure of blowout preventers in the drill string in the prior art. Attached Figure Description

[0019] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0020] Figure 1 A schematic diagram of the baffle of the drill bit blowout preventer in its initial state, according to a specific embodiment of the present invention, is shown; and

[0021] Figure 2 This diagram illustrates a specific embodiment of the present invention where the baffle of the drill bit blowout preventer is in a blocked state.

[0022] Figure 3 A schematic diagram of the valve core of a blowout preventer tool inside a drill bit is shown in a specific embodiment of the present invention;

[0023] Figure 4 A flowchart of a blowout prevention method for drill bits according to a specific embodiment of the present invention is shown.

[0024] The above figures include the following reference numerals:

[0025] 10. Valve body; 11. Hollow flow channel; 20. Valve core; 21. Hollow cavity; 211. First hollow cavity; 212. Second hollow cavity; 22. Partition; 221. First central through hole; 23. Second central through hole; 24. Overflow trigger hole; 25. Rib; 30. Baffle; 31. Pressure measuring hole; 40. Stop; 50. Reset component; 60. First seal; 70. Second seal; 80. Third seal; 90. Shaft pin. Detailed Implementation

[0026] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0027] It should be noted that, unless otherwise specified, all technical and scientific terms used in this application have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains.

[0028] In this invention, unless otherwise stated, directional terms such as "upper," "lower," "top," and "bottom" are generally used in relation to the direction shown in the accompanying drawings, or in relation to the vertical, perpendicular, or gravitational direction of the component itself; similarly, for ease of understanding and description, "inner" and "outer" refer to the inner and outer contours of each component itself, but the above directional terms are not intended to limit this invention.

[0029] Obviously, the embodiments described above are merely some, not all, embodiments of the present invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort should fall within the scope of protection of the present invention.

[0030] To address the problem of easy failure of internal blowout preventers in existing drill bits, this invention provides an internal blowout preventer and method for drill bits.

[0031] like Figures 1 to 3As shown, the blowout preventer (BOP) in the drill bit includes a valve body 10, a valve core 20, and a baffle 30. The valve body 10 has a hollow flow channel 11 extending axially. The valve core 20 is disposed within the hollow flow channel 11 and is sealed to the inner wall of the valve body 10. The valve core 20 has a hollow cavity 21 that communicates with the hollow flow channel 11. The valve core 20 includes a partition 22 that divides the hollow cavity 21 into a first hollow cavity 211 and a second hollow cavity 212. The partition 22 has a first central through hole 221, and the lower end face of the valve core 20 has a second central through hole 23. The baffle 30 is disposed within the second hollow cavity 212, and one end of the baffle 30 is rotatably connected to the side wall of the valve core 20. The baffle 30 has an initial state and a blocking state. In the initial state, the baffle 30 is set at an acute angle to the partition 22 to avoid the first central through hole 221. When overflow or blowout occurs, the drilling fluid enters the hollow cavity 21 from the hollow flow channel 11 and moves upward. The drilling fluid drives the baffle 30 to flip in the direction close to the partition 22 and block the first central through hole 221. The baffle 30 switches from the initial state to the blocking state.

[0032] The drill bit's blowout preventer includes a valve body 10, a valve core 20, and a baffle 30. The valve body 10 has an axially extending hollow flow channel 11. The valve core 20 is disposed within the hollow flow channel 11 and is sealed to the inner wall of the valve body 10. The valve core 20 has a hollow cavity 21 that communicates with the hollow flow channel 11. The valve core 20 includes a partition 22 that divides the hollow cavity 21 into a first hollow cavity 211 and a second hollow cavity 212. The partition 22 has a first central through hole 221, and the lower end face of the valve core 20 has a second central through hole 23. The baffle 30 is disposed within the second hollow cavity 212. One end of the baffle 30 is rotatably connected to the side wall of the valve core 20. The baffle 30 has an initial state and a blocked state. In the initial state, the baffle 30 is positioned at an acute angle to the partition 22 to avoid collision. In the event of a blowout or overflow, drilling fluid enters the hollow cavity 21 from the hollow flow channel 11 and moves upward. The drilling fluid causes the baffle 30 to flip along the direction close to the partition 22 and block the first central through-hole 221. The baffle 30 switches from the initial state to the blocked state. In this way, when no blowout or overflow occurs, the baffle 30 always avoids the first central through-hole 221, thereby avoiding the impact of drilling fluid on the baffle 30. The baffle 30 will only be impacted by drilling fluid and flipped upward when a blowout or overflow occurs, thereby blocking the first central through-hole 221 to prevent the blowout from developing further. The above settings prevent the baffle 30 from repeatedly flipping under the impact of fluid in the drill string, thereby greatly reducing wear and fatigue, improving service life, and ensuring the long-term effectiveness of the blowout prevention tool in the drill string.

[0033] It should be noted that "baffle 30 avoiding the first central through hole 221" means that baffle 30 is completely outside the first central through hole 221 in the axial direction, thereby ensuring the normal flow of drilling fluid within the drill string during drilling. To further ensure the avoidance effect of baffle 30 on the first central through hole 221, such as... Figures 1 to 3 As shown, the blowout preventer inside the drill bit also includes a stop 40. The stop 40 is disposed on the lower end face of the valve core 20 and located on the side of the second central through hole 23 near the baffle 30. In the initial state, the stop 40 and the other end of the baffle 30 form a limiting stop. Specifically, as... Figures 1 to 2 As shown, a raised rib 25 is provided on the lower end face of the valve core 20. The raised rib 25 extends upward from the lower end face of the valve core 20, and a stop member 40 is provided on the raised rib 25 so that the stop member 40 can limit and stop the other end of the baffle 30. It can be understood that the stopping effect of the stop member 40 on the baffle 30 is limited, just enough to limit and stop the baffle 30 under normal conditions, so as to ensure that the baffle 30 can be driven by the drilling fluid to break free from the restraint of the stop member 40 and flip upward during overflow.

[0034] In this embodiment, the baffle 30 is normally stopped by the stop member 40, thereby keeping the water hole inside the drill string unobstructed and completing normal drilling. During the drilling process, there is no need to inject grout into the drill string, avoiding the situation where the baffle of the conventional blowout preventer tool inside the drill string is always in a blocked state, requiring the injection of mud into the drill string during drilling to ensure force balance, and preventing damage caused by unidirectional pressure on the baffle 30; in addition, it also saves the time of special stop operation for grouting.

[0035] As shown in Figure 1 to Figure 2As shown, an overflow activation hole 24 is also provided on the lower end face of the valve core 20. The overflow activation hole 24 is spaced apart from the second central through hole 23 and located on the side near the baffle 30. The diameter of the overflow activation hole 24 is smaller than the diameter of the second central through hole 23. Specifically, the overflow activation hole 24 is located between the rib 25 and the side wall of the valve core 20, so that the rib 25, the stop member 40, the baffle 30, the side wall of the valve core 20, and the lower end face of the valve core 20 form an independent closed space. When overflow or blowout occurs, drilling fluid enters the closed space from the overflow activation hole 24, thereby causing the baffle 30 to flip upward and block the first central through hole 221. Since the enclosed space occupies only a portion of the second hollow cavity 212 and is a long and narrow space, and the diameter of the overflow activation hole 24 is smaller than the diameter of the second central through hole 23, the impact force of the drilling fluid entering the enclosed space from the overflow activation hole 24 on the baffle 30 is greater than the resistance of the drilling fluid entering the second hollow cavity 212 from the second central through hole 23. Therefore, the baffle 30 can ensure upward rotation to achieve the sealing effect. Furthermore, the overflow activation hole 24 is a funnel shape with a gradually decreasing diameter along the direction towards the partition 22. Through the above arrangement, the drilling fluid entering the enclosed space from the overflow activation hole 24 has greater kinetic energy, thereby having a greater impact force to drive the baffle 30 to rotate upward.

[0036] like Figures 1 to 3 As shown, the blowout preventer inside the drill bit also includes a reset member 50. The reset member 50 is located at the connection between one end of the baffle 30 and the side wall of the valve core 20, and is used to provide preload between the baffle 30 and the stop member 40. It can be understood that the preload between the baffle 30 and the stop member 40 is less than the restraining force of the stop member 40 on the baffle 30.

[0037] like Figures 1 to 3 As shown, the blowout preventer inside the drill bit also includes a pivot pin 90. One end of the baffle 30 is fitted onto the pivot pin 90, thereby rotating along the pivot pin 90. In this embodiment, the reset member 50 is a retaining spring, which is fitted onto the pivot pin 90 and abuts against the baffle 30 to provide preload. Of course, the reset member 50 can also be other elastic elements, which can be selected according to actual needs.

[0038] In this embodiment, the sealing surface of the baffle 30 is an outwardly convex curved surface, and the shape of the first central through-hole 221 is adapted to the sealing surface of the baffle 30. That is, the baffle 30 is bowl-shaped, and the first central through-hole 221 is basin-shaped to match it. Through the above arrangement, the contact surface between the baffle 30 and the partition 22 is curved, which has a better sealing effect and ensures the sealing effect of the baffle 30 on the first central through-hole 221.

[0039] like Figures 1 to 3As shown, the baffle 30 has a pressure measuring hole 31. The pressure measuring hole 31 penetrates the baffle 30 axially. By setting the pressure measuring hole 31, after the baffle 30 blocks the first central through hole 221, the first hollow cavity 211 and the second hollow cavity 212 can be connected. A small amount of drilling fluid can pass through the pressure measuring hole 31, thus forming a pressure channel with the drilling platform. At this time, the surface riser can directly measure the downhole pressure, thus providing a strong basis for accurately judging the downhole conditions. In addition, the pressure measuring hole 31 has a small diameter, so only a small amount of drilling fluid can pass through. Under these circumstances, the flow rate of the drilling fluid is within an acceptable range and will not cause a blowout.

[0040] like Figures 1 to 3 As shown, the blowout preventer inside the drill bit also includes seals. The seals include a first seal 60, a second seal 70, and a third seal 80. The first seal 60 and the second seal 70 are spaced apart and disposed on the outer surface of the upper end of the valve core 20. The third seal 80 is disposed on the outer surface of the lower end of the valve core 20.

[0041] In this embodiment, the first sealing element 60, the second sealing element 70, and the third sealing element 80 are all rubber rings. Specifically, three annular grooves are respectively formed on the outer surface of the valve core 20. The first sealing element 60, the second sealing element 70, and the third sealing element 80 are respectively accommodated in the three annular grooves, with a portion protruding from the annular grooves, thereby abutting against the inner wall of the valve body 10 to achieve a sealing connection. Of course, the position and number of sealing elements can also be determined according to actual needs, as long as the sealing requirements are met.

[0042] In this embodiment, the baffle 30 is made of metal. Correspondingly, the overall structure of the valve core 20 is also made of metal. This ensures a metal-to-metal seal between the baffle 30 and the partition 22, resulting in a better sealing effect and guaranteeing the sealing effect of the baffle 30 on the first central through hole 221.

[0043] Furthermore, the baffle 30 is made of the same material as the valve core 20. This design prevents electrochemical corrosion between the baffle 30 and the valve core 20, thus ensuring the service life of the baffle 30.

[0044] In this embodiment, both ends of the valve body 10 are provided with threads for connection with the drill string. Specifically, the upper end of the valve body 10 has a female thread, and the lower end of the valve body 10 has a male thread. The male thread end of the upper drill string is connected to the female thread of the valve body 10 and can directly press against the upper end surface of the valve core 20. Furthermore, the hollow flow channel 11 has a stepped surface, and the lower end surface of the valve core 20 is mounted on the stepped surface. Through the above arrangement, the valve core 20 is prevented from moving upward along the water hole of the drill string during drilling or overflow, and the valve core of the conventional blowout preventer tool in the drill string is prevented from moving freely within the water hole of the drill string without restriction.

[0045] like Figure 4 As shown, this application also provides a method for preventing blowout within the drill string. The method employs the aforementioned blowout preventer tool and includes: limiting and stopping the baffle 30 and stop 40 of the blowout preventer tool; connecting the blowout preventer tool to the drill string and lowering them together into the well; in the event of overflow or blowout, drilling fluid flows back into the hollow cavity 21 of the blowout preventer tool, causing the baffle 30 to flip and block the first central through-hole 221 of the blowout preventer tool, thus preventing the drilling fluid from flowing upward; measuring the bottom hole pressure through the pressure measuring hole 31 of the blowout preventer tool; and during tripping, the baffle 30 naturally falls back to avoid the first central through-hole 221, allowing the drilling fluid inside the blowout preventer tool to flow back into the well.

[0046] Specifically, after the blowout preventer (BOP) is connected inside the drill string and lowered into the well, during normal drilling, the baffle 30 is blocked by the stop 40 and is in a drooping state. The drilling fluid flows downward through the first central through-hole 221 and the second central through-hole 23 of the valve core 20, participating normally in drilling operations. During drilling, the baffle 30 and the stop 40 are already limited and stopped on the surface to keep the water holes inside the drill string unobstructed, completing normal drilling. When high-pressure brine or oil and gas is encountered at the bottom of the well, and a sudden overflow occurs, because the bottom pressure is higher than the pressure inside the drill string, the drilling fluid flows back into the drill string through the drill bit water holes. The drilling fluid moves upward through the overflow trigger hole 24, and the resulting force triggers the baffle 30 to push aside the stop 40 and move upward, forming a seal with the baffle 22, blocking the drilling fluid from flowing upward along the inside of the drill string and preventing a blowout inside the drill string.

[0047] In the event of a blowout, after shutting in the well, the pressure measurement hole 31 on the baffle 30 allows the bottom hole pressure to be transmitted along the drill string to the drill platform. Once the pressure stabilizes, it can be directly read using a standpipe pressure gauge. Furthermore, because this hole is relatively small, it prevents blowouts within the drill string. Traditional drill string blowout preventers, on the other hand, require a small-displacement pump to open a water channel to the bottom of the well to obtain the bottom hole pressure. This can create reverse high pressure on surface equipment, posing a significant risk.

[0048] When the drill string is pulled out, the pressure of the drilling fluid column inside the drill string is greater than the pressure at the bottom of the well. The baffle 30 falls back naturally, and the drilling fluid flows back into the well under the action of the pressure difference at the bottom of the well. This avoids the drilling fluid inside the drill string flowing onto the drilling platform when the drill string is removed, thus preventing pollution of the working environment on the drilling platform.

[0049] From the above description, it can be seen that the above embodiments of the present invention achieve the following technical effects: A valve body 10, a valve core 20, and a baffle 30 are provided in the blowout preventer tool inside the drill bit. The valve body 10 has a hollow flow channel 11 extending axially. The valve core 20 is disposed within the hollow flow channel 11 and is sealed to the inner wall of the valve body 10. The valve core 20 has a hollow cavity 21, which communicates with the hollow flow channel 11. The valve core 20 includes a partition 22, which divides the hollow cavity 21 into a first hollow cavity 211 and a second hollow cavity 212. The partition 22 has a first central through hole 221, and the lower end face of the valve core 20 has a second central through hole 23. The baffle 30 is disposed within the second hollow cavity 212. One end of the baffle 30 is rotatably connected to the side wall of the valve core 20. The baffle 30 has an initial state and a blocked state. In the initial state, the baffle... The baffle 30 is set at an acute angle to the baffle 22 to avoid the first central through hole 221. When overflow or blowout occurs, the drilling fluid enters the hollow cavity 21 from the hollow flow channel 11 and moves upward. The drilling fluid drives the baffle 30 to flip along the direction close to the baffle 22 and block the first central through hole 221. The baffle 30 switches from the initial state to the blocking state. In this way, when no overflow or blowout occurs, the baffle 30 always avoids the first central through hole 221, thereby avoiding the impact of the drilling fluid on the baffle 30. The baffle 30 will only be impacted by the drilling fluid and flipped upward when overflow or blowout occurs, thereby blocking the first central through hole 221 to prevent the overflow from developing further. The above arrangement makes the baffle 30 not repeatedly flipped under the impact of the fluid in the drill string, thereby greatly reducing wear and fatigue, improving service life, and ensuring the long-term effectiveness of the blowout prevention tool in the drill string.

[0050] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0051] It should be noted that the terms "first," "second," etc., used in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments of this application described herein can be implemented in sequences other than those illustrated or described herein.

[0052] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A blowout preventer for drill bits, characterized in that, include: Valve body (10), the valve body (10) having a hollow flow channel (11) extending in the axial direction. The valve core (20) is disposed in the hollow flow channel (11) and sealed to the inner wall of the valve body (10). The valve core (20) has a hollow cavity (21) which is connected to the hollow flow channel (11). The valve core (20) includes a partition (22) which divides the hollow cavity (21) into a first hollow cavity (211) and a second hollow cavity (212). The partition (22) has a first central through hole (221) and a second central through hole (23) on the lower end face of the valve core (20). A baffle (30) is disposed in the second hollow cavity (212), and one end of the baffle (30) is rotatably connected to the side wall of the valve core (20); The baffle (30) has an initial state and a blocking state. In the initial state, the baffle (30) is set at an acute angle to the partition (22) to avoid the first central through hole (221). When overflow or blowout occurs, the drilling fluid enters the hollow cavity (21) from the hollow flow channel (11) and moves upward. The drilling fluid drives the baffle (30) to flip in the direction close to the partition (22) and block the first central through hole (221). The baffle (30) switches from the initial state to the blocking state. The lower end face of the valve core (20) is also provided with an overflow activation hole (24), which is spaced apart from the second central through hole (23) and located on the side close to the baffle (30); The blowout preventer inside the drill bit also includes a stop (40). The internal blowout preventer of the drill bit also includes a reset member (50), which is disposed at the connection between one end of the baffle (30) and the side wall of the valve core (20) to provide preload between the baffle (30) and the stop member (40).

2. The drill bit internal blowout preventer according to claim 1, characterized in that, The stop (40) is disposed on the lower end face of the valve core (20) and located on the side of the second central through hole (23) near the baffle (30). In the initial state, the stop (40) and the other end of the baffle (30) form a limiting stop.

3. The drill bit internal blowout preventer according to claim 1, characterized in that, The overflow activation hole (24) is a funnel shape with a gradually decreasing aperture along the direction toward the partition (22).

4. The drill bit blowout preventer according to claim 1, characterized in that, The sealing surface of the baffle (30) is an outwardly convex curved surface, and the shape of the first central through hole (221) is adapted to the sealing surface of the baffle (30).

5. The drill bit blowout preventer according to claim 1, characterized in that, The baffle (30) has a pressure measuring hole (31) that extends through the baffle (30) axially.

6. The drill bit blowout preventer according to claim 1, characterized in that, The blowout preventer inside the drill bit also includes a seal, the seal comprising: First seal (60); The second seal (70) is provided at a distance from the first seal (60) and the second seal (70) on the outer surface of the upper end of the valve core (20); The third seal (80) is disposed on the outer surface of the lower end of the valve core (20).

7. The drill bit blowout preventer according to any one of claims 1 to 5, characterized in that, The baffle (30) is made of metal; and / or The baffle (30) is made of the same material as the valve core (20).

8. The drill bit blowout preventer according to any one of claims 1 to 5, characterized in that, Both ends of the valve body (10) are provided with threads for connection with the drill bit.

9. A method for preventing blowout inside a drill bit, characterized in that, The blowout prevention method is implemented using the blowout prevention tool inside the drill bit according to any one of claims 1 to 5, the blowout prevention method comprising: The baffle (30) of the blowout preventer inside the drill string is limited and stopped by the stop (40), and the blowout preventer inside the drill string is connected to the drill string and lowered into the well together; When an overflow or blowout occurs, the drilling fluid flows back into the hollow cavity (21) of the blowout preventer inside the drill string, causing the baffle (30) to flip and block the first central through hole (221) of the blowout preventer inside the drill string, thus blocking the upward flow of the drilling fluid. The bottom hole pressure is measured through the pressure measuring hole (31) of the blowout preventer inside the drill string; When the drill string is pulled out, the baffle (30) naturally falls back to avoid the first central through hole (221), and the drilling fluid in the blowout preventer in the drill string flows back into the well.

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