A blowout preventer for oil drilling and method of use

Abstract

The present application relates to the technical field of oil exploitation, in particular to a blowout preventer for oil drilling and a use method thereof, which comprises a main pipeline, an inclined surface block is fixedly connected to the inner side wall of the main pipeline, a flow pipeline is fixedly connected to the side surface of the side of the inclined surface block away from the inner side wall of the main pipeline, two sealing blocks are arranged on the outer side wall of the main pipeline, the two sealing blocks are symmetrically arranged and are connected to each other through bolts, and the bolt connection portions of the two sealing blocks are sleeved and communicated with the side wall of the main pipeline. The flow pipeline can be closed by using the first and second flappers, and in the process of closing, the flowing liquid flows to the upper port of the main pipeline through the plurality of through holes, and the force acting on the first and second flappers is much smaller than the force acting on the flow pipeline directly closed by the liquid impact.

Description

A blowout preventer for oil drilling and its application method Technical Field

[0001] This invention relates to a blowout preventer, and more particularly to a blowout preventer for oil drilling and its application method, belonging to the field of oil extraction technology. Background Technology

[0002] A blowout preventer (BOP) is used to close the wellhead during drilling, well testing, workover, and well completion operations to prevent blowout accidents. It combines the functions of full and partial sealing. Due to the many uncertainties and complexities in the formation, every drilling operation has the possibility of a blowout. As the most important well control equipment, the BOP needs to be activated quickly to shut in the well in case of emergencies such as overflow, kick, or blowout. If the BOP fails at this time, it will lead to serious accidents such as blowouts. Therefore, the proper design of the BOP plays an important role in ensuring the smooth progress of drilling operations and personal safety.

[0003] In general, gate valve blowout preventers work by using a drive mechanism on both sides to merge two gates and seal them above the pipeline to prevent underground liquid from overflowing and causing a blowout. However, during use, because the gates are moved above the pipeline opening, when liquid surges up from below, the surging liquid exerts an upward force on the moving gates. This upward force causes a difference in the force experienced by the upper and lower surfaces of the gate. Consequently, the friction between the upper surface and the device is greater than that between the lower surface and the device during movement. After frequent use, the upper surface of the gate wears down and becomes uneven, while the lower surface, after receiving the full force of the surging liquid, shifts upward during movement, resulting in gaps between the lower surface of the gate and the device, ultimately leading to liquid leakage. During this process, the gate is constantly subjected to the full force of the surging liquid, and this wear is most severe on the upper surface of the gate during its movement.

[0004] Therefore, it is urgent to improve the blowout preventer (BOP) for oil drilling to solve the aforementioned problems. Summary of the Invention

[0005] The purpose of this invention is to provide a blowout preventer for oil drilling and its usage method. It can seal the upper port of the flow pipe using a first gate and a second gate. During the sealing process, because the flow pipe has several through holes, after the upper port of the flow pipe is sealed, the flowing liquid will then flow through these through holes to the upper port of the main pipe. Due to the guiding effect of the through holes, the force on the first and second gates is much less than the liquid impact force received by directly sealing the flow pipe. Then, the threaded sealing pipe is rotated to cover and seal the through holes, thus blocking the liquid within the flow pipe. When necessary, the first and second gates can be opened for subsequent drilling work. During this process, the liquid impact force received by the first and second gates when they move is much less than the impact force of directly sealing the liquid, greatly reducing the wear on the upper surfaces of the first and second gates and significantly increasing the service life of the device.

[0006] To achieve the above objectives, the main technical solution adopted by the present invention includes: an oil well blowout preventer, comprising a main pipe, an inclined block fixedly connected to the inner wall of the main pipe, a flow pipe fixedly connected to the side of the inclined block away from the inner wall of the main pipe, two sealing blocks provided on the outer wall of the main pipe, the two sealing blocks being symmetrically arranged and connected to each other by bolts, the bolted connection of the two sealing blocks being sleeved on the side wall of the main pipe, each of the two sealing blocks having a sliding groove, and the two sliding grooves being located at the ends of the two sealing blocks near the main pipe, a gate valve assembly for closing the upper end of the flow pipe being slidably connected in the two sliding grooves, a plurality of through holes being provided on the side wall of the flow pipe, the plurality of through holes being equidistantly arranged around the central axis of the flow pipe, a rotating assembly for closing the plurality of through holes being threadedly connected to the outer surface of the flow pipe, and the rotating assembly being initially located below the plurality of through holes and above the inclined block.

[0007] Preferably, a hydraulic rod is fixedly provided inside each of the two sealing blocks. The two hydraulic rods are respectively located at the ends of the two sealing blocks away from the main pipe, and the movable ends of the two hydraulic rods are respectively slidably connected to the two sliding grooves. A sealing ring block is fixedly connected to the side of the two sliding grooves away from the main pipe, and the two sealing ring blocks are located at the sliding connection points between the two hydraulic rods and the two sliding grooves and are respectively slidably sleeved on the outer surface of the movable ends of the two hydraulic rods.

[0008] Preferably, the gate valve assembly includes a first gate and a second gate. The first gate is slidably connected in one of the sliding grooves, and a square protrusion is provided on the side of the first gate near the main pipeline. The second gate is slidably connected in the other sliding groove, and a square groove is provided on the side of the second gate near the main pipeline. Several leakage holes are provided on the first and second gates respectively.

[0009] Preferably, the lower surfaces of the first gate and the second gate are at the same level as the upper end face of the flow pipe, and the sides of the first gate and the second gate away from the main pipe are respectively fixedly connected to the movable ends of the two hydraulic rods.

[0010] Preferably, the rotating assembly includes a threaded sealing tube, a support ring block, and a merging ring. The threaded sealing tube is threadedly connected to the outer surface of the flow pipe. In its initial state, the threaded sealing tube is located below several through holes. The inner side of one end of the threaded sealing tube that enters several through holes is in contact with the outer side of the flow pipe. The inner side of the end of the threaded sealing tube that is away from several through holes is threadedly connected to the outer surface of the flow pipe. The support ring block is fixedly connected to the inner wall of the main pipe and is located between the outer wall of the threaded sealing tube near several through holes and the inner wall of the flow pipe. The inner wall of the support ring block is in contact with the outer wall of the threaded sealing tube. The merging ring is fixedly connected to the outer wall of the flow pipe and is located above several through holes. An annular protrusion is fixedly connected to one end of the threaded sealing tube near the merging ring, and an annular groove is formed on one side of the merging ring near the threaded sealing tube.

[0011] Preferably, a rotating plate is movably connected to the threaded sealing tube, and a plurality of elongated protrusions are fixedly connected to the rotating plate. The plurality of elongated protrusions are equidistantly arranged around the central axis of the flow pipe. An annular rack is rotatably connected to the outer surface of the flow pipe. One end of the rotating plate away from the threaded sealing tube is fixedly connected to one side of the annular rack, and the annular rack is located above the inclined block.

[0012] Preferably, a structural box is fixedly connected to the outer side of the main pipe, and a rotating shaft is rotatably connected between the top wall and the bottom wall of the structural box. A rotating gear is fixedly connected to the outer side of one end of the rotating shaft near the bottom wall of the structural box. The outer side of the rotating gear extends through the side wall of the main pipe into the interior of the main pipe and meshes with the annular rack.

[0013] Preferably, a first bevel gear is fixedly connected to one end of the rotating shaft near the bottom wall of the structural box, a rotating rod is rotatably connected to the side of the structural box away from the main pipe, the rotating rod passes through the structural box and extends into the interior of the structural box, a second bevel gear is fixedly connected to one end of the rotating rod inside the structural box, the second bevel gear meshes with the first bevel gear, and a handle is fixedly connected to one end of the rotating rod away from the interior of the structural box.

[0014] Preferably, a plurality of supporting vertical plates are fixedly connected between the inner wall of the main pipe and the outer wall of the flow pipe, and the plurality of supporting vertical plates are equidistantly arranged around the central axis of the main pipe, and the plurality of supporting vertical plates are all located above the merging ring.

[0015] A method for using a blowout preventer in oil well drilling includes the following steps:

[0016] S1: First, when in use, the liquid from below the main pipe will flow into the upper port of the main pipe through the flow pipe. Activate the two hydraulic rods to move the No. 1 gate and the No. 2 gate towards the upper port of the flow pipe. When the square protrusion and the square groove merge together, the No. 1 gate and the No. 2 gate together close the upper port of the flow pipe.

[0017] S2: Then, after the upper port of the flow pipe is closed, the liquid flowing through the flow pipe will be forced to change its flow direction from passing through several through holes to the space between the flow pipe and the main pipe, and then continue to flow towards the upper end port of the main pipe through several leakage holes on the first and second gates.

[0018] S3: Then, turn the handle, which in turn drives the first bevel gear to rotate through the second bevel gear. Then, the rotating shaft drives the rotating gear to rotate. The rotating gear then drives the ring rack to rotate on the outer surface of the flow pipe. The ring rack drives the threaded sealing tube to rotate through the screw plate. The threaded sealing tube will move upward while rotating until the annular protrusion engages with the annular groove.

[0019] S4: Finally, the inner wall of the threaded sealing tube, after the annular protrusion and the annular groove are engaged, covers several through holes. At this time, the liquid from the lower port of the main pipe no longer flows to the upper port of the main pipe, blocking the gushing liquid in the flow pipe.

[0020] This invention has at least the following beneficial effects:

[0021] 1. By using gate valves No. 1 and No. 2 to seal the upper port of the flow pipe, the flowing liquid will then flow to the upper port of the main pipe through several through holes after the upper port of the flow pipe is sealed. Due to the guiding effect of the through holes, the force on gate valves No. 1 and No. 2 is much less than the liquid impact force received by directly sealing the flow pipe. Then, the threaded sealing pipe is rotated to cover and seal the through holes. At this time, the liquid will be blocked in the flow pipe. When necessary, gate valves No. 1 and No. 2 can be opened for subsequent drilling work. During this process, the liquid impact force received by gate valves No. 1 and No. 2 when moving is much less than the impact force of directly sealing the liquid, which greatly reduces the wear on the upper surface of gate valves No. 1 and No. 2 and greatly increases the service life of the device. Attached Figure Description

[0022] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0023] Figure 1 is a three-dimensional structural schematic diagram provided by the present invention;

[0024] Figure 2 is a cross-sectional view provided by the present invention;

[0025] Figure 3 is a second cross-sectional view provided by the present invention;

[0026] Figure 4 is an enlarged schematic diagram of the structure at point A in Figure 3 provided by the present invention;

[0027] Figure 5 is a schematic diagram of the gate valve assembly structure provided by the present invention;

[0028] Figure 6 is a schematic diagram of the rotating component structure provided by the present invention;

[0029] Figure 7 is a schematic diagram of the twisting plate and the annular rack structure provided by the present invention.

[0030] In the diagram: 1. Main pipe; 2. Inclined block; 3. Flow pipe; 4. Sealing block; 5. Sliding groove; 6. Through hole; 7. Hydraulic rod; 8. Gate valve assembly; 801. Gate 1; 802. Gate 2; 803. Square protrusion; 804. Square groove; 805. Leakage hole; 9. Rotating assembly; 901. Threaded sealing pipe; 902. Support ring block; 903. Merging ring; 904. Annular protrusion; 905. Annular groove; 10. Sealing ring block; 11. Twisting plate; 12. Long strip protrusion; 13. Annular rack; 14. Structural box; 15. Rotating shaft; 16. Rotating gear; 17. First bevel gear; 18. Second bevel gear; 19. Rotating rod; 20. Handle; 21. Support vertical plate. Detailed Implementation

[0031] The following will describe in detail the implementation of this application with reference to the accompanying drawings and embodiments, so that the implementation process of how this application uses technical means to solve technical problems and achieve technical effects can be fully understood and implemented accordingly.

[0032] As shown in Figures 1-7, the blowout preventer for oil drilling provided in this embodiment includes a main pipe 1. A ramp block 2 is fixedly connected to the inner wall of the main pipe 1. The ramp of the ramp block 2 guides the liquid from the lower port of the main pipe 1 into a flow pipe 3, and the ramp is not subjected to impact from the liquid, ensuring it will not deform. A flow pipe 3 is fixedly connected to the side of the ramp block 2 away from the inner wall of the main pipe 1. Two sealing blocks 4 are provided on the outer wall of the main pipe 1, and the two sealing blocks 4 are symmetrically arranged and connected to each other by bolts. The bolted connection of the two sealing blocks 4 is fitted onto the side wall of the main pipe 1. Each of the two sealing blocks 4 has a sliding groove 5, and the two sliding grooves 5 are located at the ends of the two sealing blocks 4 closest to the main pipe 1. A gate valve assembly 8 for closing the upper port of the flow pipe 3 is slidably connected in both sliding grooves 5. The flow pipe 3 has a... The system has several through holes 6, which are equidistantly arranged around the central axis of the flow pipe 3. A rotating component 9 for sealing the through holes 6 is threadedly connected to the outer surface of the flow pipe 3. In its initial state, the rotating component 9 is located below the through holes 6 and above the inclined block 2. Hydraulic rods 7 are fixedly installed in both sealing blocks 4. The two hydraulic rods 7 are located at the ends of the two sealing blocks 4 away from the main pipe 1, and the movable ends of the two hydraulic rods 7 are slidably connected to the two sliding grooves 5. Sealing rings 10 are fixedly connected to the sides of the two sliding grooves 5 away from the main pipe 1. The two sealing rings 10 are located at the sliding connection points between the two hydraulic rods 7 and the two sliding grooves 5 and are slidably sleeved on the outer surface of the movable ends of the two hydraulic rods 7. The sealing rings 10 ensure the sealing of the connection points between the movable ends of the hydraulic rods 7 and the sliding grooves 5 when the movable ends of the hydraulic rods 7 slide in the sliding grooves 5.

[0033] As shown in Figures 5 and 6, the gate valve assembly 8 includes a first gate 801 and a second gate 802. The first gate 801 is slidably connected in one of the sliding grooves 5, and a square protrusion 803 is provided on the side of the first gate 801 near the main pipe 1. The second gate 802 is slidably connected in the other sliding groove 5, and a square groove 804 is provided on the side of the second gate 802 near the main pipe 1. Several leakage holes 805 are provided on the first gate 801 and the second gate 802. The lower surfaces of the first gate 801 and the second gate 802 are at the same level as the upper end face of the flow pipe 3. The sides of the first gate 801 and the second gate 802 away from the main pipe 1 are fixedly connected to the movable ends of two hydraulic rods 7. The rotating assembly 9 includes a threaded sealing tube 901, a support ring block 902, and a merging ring 903. The threaded sealing tube 901 is threaded... The threaded sealing tube 901 is initially located below several through holes 6. The inner side of the threaded sealing tube 901, which is inserted into several through holes 6, is in contact with the outer side of the flow pipe 3. The inner side of the threaded sealing tube 901, which is away from several through holes 6, is threadedly connected to the outer surface of the flow pipe 3. The support ring 902 is fixedly connected to the inner wall of the main pipe 1. The support ring 902 is located between the outer wall of the threaded sealing tube 901 near several through holes 6 and the inner wall of the flow pipe 3. The inner wall of the support ring 902 is in contact with the outer wall of the threaded sealing tube 901. The merging ring 903 is fixedly connected to the outer wall of the flow pipe 3. The merging ring 903 is located above several through holes 6. An annular protrusion 904 is fixedly connected to the end of the threaded sealing tube 901 near the merging ring 903. An annular groove 905 is opened on the side of the merging ring 903 near the threaded sealing tube 901.

[0034] Furthermore, as shown in Figures 1-7, a rotating plate 11 is movably connected to the threaded sealing tube 901. Several elongated protrusions 12 are fixedly connected to the rotating plate 11. These protrusions 12 are equidistantly arranged around the central axis of the flow pipe 3. The protrusions 12 ensure that the threaded sealing tube 901 rotates together with the rotating plate 11. A ring-shaped rack 13 is rotatably connected to the outer surface of the flow pipe 3. The end of the rotating plate 11 away from the threaded sealing tube 901 is connected to one side of the ring-shaped rack 13. The sides are fixedly connected, and the annular rack 13 is located above the inclined block 2. A structural box 14 is fixedly connected to the outer side of the main pipe 1. A rotating shaft 15 is rotatably connected between the top wall and the bottom wall of the structural box 14. A rotating gear 16 is fixedly connected to the outer side of the end of the rotating shaft 15 near the bottom wall of the structural box 14. The outer side of the rotating gear 16 penetrates the side wall of the main pipe 1 and extends into the interior of the main pipe 1, meshing with the annular rack 13. The support ring block 902 and the inclined block 2 work together to connect the space between them. The space between the main pipe 1 and the flow pipe 3 is blocked by other spaces. A first bevel gear 17 is fixedly connected to one end of the rotating shaft 15 near the bottom wall of the structural box 14. A rotating rod 19 is rotatably connected to the side of the structural box 14 away from the main pipe 1. The rotating rod 19 passes through the structural box 14 and extends into its interior. A second bevel gear 18 is fixedly connected to one end of the rotating rod 19 inside the structural box 14. The second bevel gear 18 meshes with the first bevel gear 17. The rotating rod 19 is located away from the interior of the structural box 14. One end is fixedly connected to a handle 20. When the handle 20 is rotated, it drives the first bevel gear 17 to rotate through the second bevel gear 18. Then, it drives the rotating gear 16 to rotate through the rotating shaft 15. The rotating gear 16 then drives the annular rack 13 to rotate on the outer surface of the flow pipe 3. The annular rack 13 drives the threaded sealing tube 901 to rotate through the screwing plate 11. The threaded sealing tube 901 moves upward while rotating until the annular protrusion 904 engages with the annular groove 905.

[0035] Furthermore, as shown in Figure 3, several supporting vertical plates 21 are fixedly connected between the inner wall of the main pipe 1 and the outer wall of the flow pipe 3. The supporting vertical plates 21 are equidistantly arranged around the central axis of the main pipe 1. The supporting vertical plates 21 are all located above the merging ring 903. The supporting vertical plates 21 ensure that the flow pipe 3 will not shift due to excessive liquid flow during operation, and ensure the liquid flowability between the flow pipe 3 and the main pipe 1 when supporting the flow pipe 3.

[0036] As shown in Figures 1-7, this embodiment provides a method for using a blowout preventer in oil drilling, which includes the following steps:

[0037] S1: First, during use, the liquid from below the main pipe 1 will flow into the upper port of the main pipe 1 through the flow pipe 3. The two hydraulic rods 7 are activated to move the first gate 801 and the second gate 802 to the upper port of the flow pipe 3. When the square protrusion 803 and the square groove 804 are combined, the first gate 801 and the second gate 802 together close the upper port of the flow pipe 3.

[0038] S2: Then, after the upper port of the flow pipe 3 is closed, the liquid flowing through the flow pipe 3 will be forced to change its flow direction from passing through several through holes 6 to the space between the flow pipe 3 and the main pipe 1, and then continue to flow towards the upper end port of the main pipe 1 through several leakage holes 805 on the first gate 801 and the second gate 802.

[0039] S3: Then, turn the handle 20, which in turn drives the first bevel gear 17 to rotate through the second bevel gear 18. Then, the rotating shaft 15 drives the rotating gear 16 to rotate. The rotating gear 16 then drives the annular rack 13 to rotate on the outer surface of the flow pipe 3. The annular rack 13 drives the threaded sealing tube 901 to rotate through the screw plate 11. The threaded sealing tube 901 will move upward while rotating until the annular protrusion 904 and the annular groove 905 are engaged.

[0040] S4: Finally, the inner wall of the threaded sealing tube 901, after the annular protrusion 904 and the annular groove 905 are engaged, covers several through holes 6. At this time, the liquid from the lower port of the main pipe 1 no longer flows to the upper port of the main pipe 1, blocking the gushing liquid in the flow pipe 3.

[0041] If certain terms are used in the specification and claims to refer to specific components, those skilled in the art will understand that hardware manufacturers may use different names to refer to the same component. This specification and claims do not distinguish components based on differences in name, but rather on differences in function. The term "comprising" as used throughout the specification and claims is an open-ended term and should be interpreted as "comprising but not limited to." "Approximately" means that within an acceptable margin of error, those skilled in the art can solve the technical problem and substantially achieve the technical effect within a certain margin of error.

[0042] It should be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a product or system comprising a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a product or system. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the product or system that includes that element.

[0043] The foregoing description illustrates and describes several preferred embodiments of the present invention. However, as previously stated, it should be understood that the present invention is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the inventive concept described herein through the foregoing teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of the present invention should be within the protection scope of the appended claims.

Claims

1. A blowout preventer for oil drilling, comprising a main pipeline (1), characterized in that: An inclined block (2) is fixedly connected to the inner wall of the main pipe (1). A flow pipe (3) is fixedly connected to the side of the inclined block (2) away from the inner wall of the main pipe (1). Two sealing blocks (4) are provided on the outer wall of the main pipe (1). The two sealing blocks (4) are symmetrically arranged and connected to each other by bolts. The bolt connection of the two sealing blocks (4) is sleeved on the side wall of the main pipe (1). Each of the two sealing blocks (4) has a sliding groove (5). The two sliding grooves (5) are located at the ends of the two sealing blocks (4) near the main pipe (1). The two sliding grooves (5) are slidably connected together to facilitate the flow pipe (3). The gate valve assembly (8) is a gate valve assembly that closes the upper end of the flow pipe (3). The flow pipe (3) has several through holes (6) on its side wall, and the several through holes (6) are equidistantly arranged around the central axis of the flow pipe (3). The outer surface of the flow pipe (3) is threaded with a rotating assembly (9) for closing the several through holes (6). The rotating assembly (9) is initially located below the several through holes (6) and above the inclined block (2). The gate valve assembly (8) includes a first gate plate (801) and a second gate plate (802). The first gate plate (801) and the second gate plate (802) are respectively provided with several leakage holes (805). The rotating assembly (9) includes a threaded sealing tube (901), a support ring (902), and a merging ring (903). The threaded sealing tube (901) is threadedly connected to the outer surface of the flow pipe (3). In its initial state, the threaded sealing tube (901) is located below several through holes (6). The inner side of one end of the threaded sealing tube (901) with several through holes (6) is in contact with the outer side of the flow pipe (3). The inner side of the end of the threaded sealing tube (901) away from several through holes (6) is threadedly connected to the outer surface of the flow pipe (3). The support ring (902) is fixedly connected to the inner wall of the main pipe (1). The support ring (902) is located between the outer wall of the threaded sealing tube (901) near one of the through holes (6) and the inner wall of the main pipe (1). The inner wall of the support ring (902) is in contact with the outer wall of the threaded sealing tube (901). The merging ring (903) is fixedly connected to the outer wall of the flow pipe (3). The merging ring (903) is located above the through holes (6). An annular protrusion (904) is fixedly connected to one end of the threaded sealing tube (901) near the merging ring (903). An annular groove (905) is opened on one side of the merging ring (903) near the threaded sealing tube (901).

2. The blowout preventer for oil drilling according to claim 1, characterized in that: Hydraulic rods (7) are fixedly installed inside both sealing blocks (4). The two hydraulic rods (7) are located at the ends of the two sealing blocks (4) away from the main pipe (1), and the movable ends of the two hydraulic rods (7) are slidably connected to the two sliding grooves (5). Sealing ring blocks (10) are fixedly connected to the side of the two sliding grooves (5) away from the main pipe (1), and the two sealing ring blocks (10) are located at the sliding connection points between the two hydraulic rods (7) and the two sliding grooves (5) and are slidably sleeved on the outer surface of the movable ends of the two hydraulic rods (7).

3. The blowout preventer for oil drilling according to claim 2, characterized in that: The first gate (801) is slidably connected in one of the sliding grooves (5). The first gate (801) has a square protrusion (803) on the side near the main pipe (1). The second gate (802) is slidably connected in the other sliding groove (5). The second gate (802) has a square groove (804) on the side near the main pipe (1).

4. The blowout preventer for oil drilling according to claim 3, characterized in that: The lower surfaces of the first gate (801) and the second gate (802) are at the same level as the upper end face of the flow pipe (3). The side of the first gate (801) and the second gate (802) away from the main pipe (1) are respectively fixedly connected to the movable ends of the two hydraulic rods (7).

5. The blowout preventer for oil drilling according to claim 4, characterized in that: A number of supporting vertical plates (21) are fixedly connected between the inner wall of the main pipe (1) and the outer wall of the flow pipe (3), and the supporting vertical plates (21) are equidistantly arranged around the central axis of the main pipe (1), and the supporting vertical plates (21) are all located above the merging ring (903).

6. The blowout preventer for oil drilling according to claim 5, characterized in that: A rotating plate (11) is movably connected to the threaded sealing tube (901). Several elongated protrusions (12) are fixedly connected to the rotating plate (11). The elongated protrusions (12) are equidistantly arranged around the central axis of the flow pipe (3). An annular rack (13) is rotatably connected to the outer surface of the flow pipe (3). One end of the rotating plate (11) away from the threaded sealing tube (901) is fixedly connected to one side of the annular rack (13). The annular rack (13) is located above the inclined block (2).

7. The blowout preventer for oil drilling according to claim 6, characterized in that: A structural box (14) is fixedly connected to the outer side of the main pipe (1). A rotating shaft (15) is rotatably connected between the top wall and the bottom wall of the structural box (14). A rotating gear (16) is fixedly connected to the outer side of one end of the rotating shaft (15) near the bottom wall of the structural box (14). The outer side of the rotating gear (16) extends through the side wall of the main pipe (1) into the interior of the main pipe (1) and meshes with the annular rack (13).

8. A blowout preventer for oil drilling according to claim 7, characterized in that: A first bevel gear (17) is fixedly connected to one end of the rotating shaft (15) near the bottom wall of the inner wall of the structural box (14). A rotating rod (19) is rotatably connected to one side of the structural box (14) away from the main pipe (1). The rotating rod (19) passes through the structural box (14) and extends into the interior of the structural box (14). A second bevel gear (18) is fixedly connected to one end of the rotating rod (19) inside the structural box (14). The second bevel gear (18) meshes with the first bevel gear (17). A handle (20) is fixedly connected to one end of the rotating rod (19) away from the interior of the structural box (14).

9. A method of using the blowout preventer for oil drilling as described in claim 8, characterized in that: The process includes the following steps: S1: First, during use, liquid from below the main pipe (1) flows into the upper port of the main pipe (1) through the flow pipe (3). Two hydraulic rods (7) are activated to move the first gate (801) and the second gate (802) to the upper port of the flow pipe (3). When the square protrusion (803) and the square groove (804) merge together, the first gate (801) and the second gate (802) together close the upper port of the flow pipe (3). S2: Then, after the upper port of the flow pipe (3) is closed, the liquid flowing through the flow pipe (3) is forced to change its flow direction from passing through several through holes (6) to the space between the flow pipe (3) and the main pipe (1), and then continues to flow towards the main pipe through several leakage holes (805) on the first gate (801) and the second gate (802). S3: Then, turn the handle (20), which in turn drives the first bevel gear (17) to rotate through the second bevel gear (18), and then drives the rotating gear (16) to rotate through the rotating shaft (15). The rotating gear (16) then drives the ring rack (13) to rotate on the outer surface of the flow pipe (3). The ring rack (13) drives the threaded sealing tube (901) to rotate through the screw plate (11). The threaded sealing tube (901) moves upward while rotating until the annular protrusion (904) and the annular groove (905) are engaged. S4: Finally, the inner wall of the threaded sealing tube (901) after the annular protrusion (904) and the annular groove (905) are engaged covers several through holes (6). At this time, the liquid from the lower port of the main pipe (1) no longer flows to the upper port of the main pipe (1), blocking the gushing liquid in the flow pipe (3).

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