Ram blowout preventer and blowout prevention structure adopting same

Abstract

The invention discloses a ram blowout preventer and a blowout prevention structure adopting the ram blowout preventer, and belongs to the technical field of petroleum drilling devices. The structure comprises an outer shell, the middle of the outer shell is provided with a main channel, the main channel is provided with a blowout prevention channel, the blowout prevention channel is provided with a flashboard mechanism, the flashboard mechanism comprises a flashboard capable of moving along the blowout prevention channel, and the end, located on the outer side, of the flashboard is provided with an electric driving device. The flashboard can enter the main channel through the electric driving device to close the main channel; a digital control mode is adopted, opening and closing of the blowout preventer are controlled through the driving motor, the whole structure is optimized according to the working principle and requirements of the blowout preventer, and the problems that in the prior art, the device is large in size, complex in structure, high in transportation and maintenance cost and low in response speed, the environment is polluted due to hydraulic oil leakage, and stroke control is difficult are solved.

Description

Technical Field

[0001] The invention relates to a gate blowout preventer and a blowout preventer structure using the gate blowout preventer, belonging to the technical field of oil drilling devices. Background Art

[0002] The gate blowout preventer is an important equipment in the well control system, mainly used to seal the wellhead and prevent the occurrence of blowout accidents. The existing gate blowout preventers are commonly manual and hydraulic. The manual gate blowout preventer requires manpower to close and open, resulting in low efficiency and high risk factor. The principle of the hydraulic gate blowout preventer is that the pressure oil from the hydraulic system enters the closing cylinder, pushing the pistons on both sides to move toward the center, closing the gate, and thus sealing the wellhead. When the gate blowout preventer needs to be opened, the pressure oil enters the opening cylinder, pushing the pistons on both sides to move outward, opening the gate, and opening the wellhead. The existing gate blowout preventer drives the gate to move left and right through the hydraulic system to open and close the wellhead, resulting in large size, complex structure, high transportation and maintenance costs, hydraulic oil leakage will also pollute the environment, and it is difficult to accurately locate the degree of opening or closing of the gate.

[0003] When the existing annular blowout preventer is shutting in, the pressure oil from the hydraulic system enters the closing cylinder, pushing the piston upward, and the rubber core is squeezed by the piston to move toward the center of the wellhead, hugging the drill bit, thereby sealing the wellhead. When there is no drill bit at the wellhead, the rubber core is squeezed toward the center of the wellhead until it fills the entire wellhead channel to prevent the high-pressure well fluid from spraying out. When the annular blowout preventer needs to be opened, the pressure oil enters the opening cylinder, pushing the piston downward, and the rubber core is squeezed by the piston. The pressure disappears and then stretches outward, and the wellhead opens. The existing annular blowout preventer drives the piston up and down through the hydraulic system, and then drives the rubber core to close and open the wellhead, resulting in a large size, complex structure, high transportation and maintenance costs, and hydraulic oil leakage will also pollute the environment. In addition, it is difficult to accurately locate the degree of opening or closing of the rubber core using hydraulic control. Summary of the invention

[0004] The purpose of the present invention is to provide a gate blowout preventer and a blowout prevention structure using the gate blowout preventer in view of the above-mentioned problems, which has a compact structure, fast response speed, safety and high efficiency, and adds a digital control and monitoring system to solve the problems of the prior art, such as large device size, complex structure, high transportation and maintenance costs, slow response speed, hydraulic oil leakage and environmental pollution, and difficult stroke control.

[0005] The technical solution adopted by the present invention is as follows:

[0006] A gate blowout preventer comprises an outer shell, a main channel is arranged in the middle of the outer shell, a blowout prevention channel is arranged in the main channel, a gate mechanism is arranged in the blowout prevention channel, the gate mechanism comprises a gate movable along the blowout prevention channel, an electric drive device is arranged at the outer end of the gate, and the electric drive device can be used to make the gate enter the main channel and then close the main channel.

[0007] Furthermore, the blowout prevention channel runs through the outer shell, and gate mechanisms are provided on both sides of the outer shell where the blowout prevention channel is located. The gates of the gate mechanisms on both sides can shear the drill pipe and extend to the middle of the main channel under the action of the electric drive device. The gates on both sides are matched to cut off the connecting channel between the wellhead and the outside.

[0008] Furthermore, two blowout prevention channels penetrating the outer shell are arranged in the main channel, and the two blowout prevention channels are arranged in parallel up and down.

[0009] Furthermore, the electric drive device includes a reducer fixed on the outer shell, and a first drive motor is fixedly arranged on the reducer, and the first drive motor drives the movement of the gate plate through the reducer.

[0010] Furthermore, the reducer has at least one input shaft, each of which is connected to the output shaft of the first drive motor. The reducer is also provided with a connecting output shaft, which is connected to the gate plate and drives the gate plate to move.

[0011] Furthermore, the connecting output shaft is a hollow structure, the connecting output shaft is sleeved on the gate plate, and is connected to the gate plate through a screw pair, and the movement of the gate plate is controlled by the screw pair.

[0012] Furthermore, two first thrust bearings are arranged between the inner side of the reducer housing and the gate plate.

[0013] Furthermore, the reducer has two input shafts, each of which is connected to a first drive motor. When working, any one or two of the first drive motors can be started to control the movement of the gate.

[0014] A blowout prevention structure, comprising at least two of the above-mentioned ram blowout preventers, wherein the ram blowout preventers are assembled in series;

[0015] Or, it comprises at least one of the above-mentioned gate blowout preventers and at least one annular blowout preventer, wherein the gate blowout preventer and the annular blowout preventer are cross-arranged and assembled in series.

[0016] Furthermore, the annular blowout preventer includes a base shell, a top cover matching the base shell is arranged on the top of the base shell, a cavity is formed inside the top cover and the base shell after being assembled, a pipe opening connected to the cavity is arranged on the top of the top cover and the bottom of the base shell, the base shell is provided with a piston, a sealing core is arranged in the cavity inside the top cover, the piston can be moved up and down by an electric drive device, and the sealing core is located on the top or above the piston.

[0017] Furthermore, a mud guard ring is provided in the cavity where the base shell and the top cover match and on the outside of the piston, the top of the mud guard ring matches the bottom of the top cover, and the bottom of the mud guard ring cooperates with the piston.

[0018] Furthermore, the electric drive device is a second drive motor, which includes a stator and a rotor. The stator is fixedly connected to the base shell, and the rotor drives the piston to move up and down. The rotor is a hollow structure, which is sleeved on the outside of the piston and assembled with the piston through a spiral pair. The piston can move up and down through the action of the spiral pair.

[0019] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0020] 1. The gate blowout preventer of the present invention adopts an electric drive gate blowout preventer. Because the hydraulic system is eliminated, the floor space is reduced, the cost of mechanical maintenance and transportation is reduced, remote control can be realized, the safety and convenience of operation are improved, and digital control is realized. The electric drive is adopted, and it is easy to be equipped with an intelligent monitoring system, which can monitor the operating status of the equipment in real time, has a faster response speed, and can quickly close the wellhead when an abnormal situation is found.

[0021] 2. The gate blowout preventer and the blowout prevention structure using the gate blowout preventer of the present invention adopt an annular blowout preventer structure design that uses a motor to drive the up and down movement of the piston, thereby realizing the closing and opening of the rubber core to the wellhead. The electric-driven annular blowout preventer eliminates the hydraulic system, reduces the floor space, reduces the cost of mechanical maintenance and transportation, can be remotely controlled, improves the safety and convenience of operation, and is conducive to realizing digital control. The use of electric drive makes it easy to equip an intelligent monitoring system, which can monitor the operating status of the equipment in real time, has a faster response speed, and can open and close the wellhead more accurately, and can quickly close the wellhead when an abnormal situation is found;

[0022] 3. The gate blowout preventer and the blowout prevention structure using the gate blowout preventer of the present invention mainly adopt an electronic control method and control the opening and closing of the blowout preventer by driving a motor in terms of operation design. The working principle and requirements realize the optimization of the entire structure, and solve the problems of the prior art such as large device size, complex structure, high transportation and maintenance costs, slow response speed, and hydraulic oil leakage that pollutes the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will now be described by way of example with reference to the accompanying drawings, in which:

[0024] Figure 1 It is a structural schematic diagram of the gate blowout preventer of the present invention.

[0025] Figure 2 It is a structural top view of the gate blowout preventer of the present invention.

[0026] Figure 3 It is a schematic diagram of the enlarged structure of the gate blowout preventer at B of the present invention.

[0027] Figure 4 It is a structural schematic diagram of the annular blowout preventer of the present invention.

[0028] Figure 5 It is a schematic diagram of the enlarged structure of the annular blowout preventer at position A of the present invention.

[0029] Markings in the figure: 1-first thrust bearing, 2-gate, 3-outer shell, 4-main channel, 5-blowout prevention channel, 6-reducer, 7-first drive motor, 8-connecting output shaft, 91-top cover, 92-sealing core, 93-piston, 94-mud guard ring, 95-second drive motor, 951-stator, 952-rotor, 96-second thrust bearing, 97-base shell, 98-cap nut, 99-shackle, 910-main sealing ring, 911-nut sealing ring, 912-first sealing ring, 913-second sealing ring, 914-third sealing ring, 915-fourth sealing ring, 916-transmission screw pair. DETAILED DESCRIPTION

[0030] All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any manner.

[0031] Any feature disclosed in this specification, unless otherwise stated, can be replaced by other equivalent or alternative features with similar purposes. That is, unless otherwise stated, each feature is only an example of a series of equivalent or similar features.

[0032] Example 1

[0033] A gate blowout preventer, such as Figures 1 to 3 As shown, it includes an outer shell 3, a main channel 4 is arranged in the middle of the outer shell 3, a blowout prevention channel 5 is arranged in the main channel 4, a gate mechanism is arranged in the blowout prevention channel 5, and the gate mechanism includes a gate 2 that can move along the blowout prevention channel 5, and an electric drive device is arranged at the end of the gate 2 located on the outside, and the gate 2 can enter the main channel 4 through the electric drive device to close the main channel 4.

[0034] In the design of this structure, the difference between this structure and the traditional structure is that this scheme adopts electric drive to realize the opening and closing of the blowout preventer, replacing the telescopic function of the traditional structure using manual, hydraulic and other methods, and the structural design is more intelligent, and it reduces the deployment of other components on site. In specific operations, it can effectively realize the compactness of on-site components, and can also more reasonably layout the drilling site, further realizing the high-efficiency operation of the blowout preventer.

[0035] In the above specific structural design, a more specific design is that the blowout prevention channel 5 runs through the outer shell 3, and gate mechanisms are provided on both sides of the blowout prevention channel 5 where the outer shell 3 is located. The gates 2 of the gate mechanisms on both sides can be extended to the middle of the main channel 4 under the action of the electric drive device, and the gates 2 on both sides are matched. In this structure, the gate mechanisms on both sides are used as a single unit, and the effect of the gate blowout preventer can be effectively achieved with the help of the mode of the unit structure.

[0036] Based on the design of the above specific structure, further, the electric drive device includes a reducer 6 fixed on the outer shell 3, and a first drive motor 7 is fixed on the reducer 6. The first drive motor 7 drives the movement of the gate plate 2 through the reducer 6.

[0037] The reducer 6 has at least one input shaft, each of which is connected to the output shaft of the first drive motor 7. The reducer 6 is also provided with a connecting output shaft 8, which is connected to the gate plate 2 through the connecting output shaft 8 and drives the gate plate 2 to move.

[0038] More specifically, the connecting output shaft 8 is a hollow structure, and the connecting output shaft 8 is sleeved on the gate plate 2. The inner wall of the connecting output shaft 8 and the outer circle of the gate plate 2 are both provided with mutually matching tooth structures, which form a spiral pair after matching, and the movement of the gate plate 2 is controlled by the spiral pair.

[0039] Two first thrust bearings 1 are further arranged between the inner side of the housing of the reducer 6 and the gate plate 2 .

[0040] In the design of the entire drive device, the overall structural design utilizes the design of the overall transmission structure to realize the entry and exit of the gate 2, and the traditional simple mechanical transmission structure is also retained in the structural design. By adopting the intelligent module design, the structure not only effectively improves a series of problems such as oil leakage of the traditional structure, but also further improves the working efficiency of the entire gate 2 blowout preventer structure. At the same time, in the working structure design, the components are all fixed on the outer shell 3 of the blowout preventer, and are all used as one of the structures of the blowout preventer. It can not only be prefabricated, integrated and transported, but also further reduces the manpower and material resources for the installation of the on-site power source, thereby significantly improving the shortcomings of the traditional structure.

[0041] Furthermore, in order to further ensure the normal operation of the entire equipment and to be able to select and adjust according to the specific application environment, as a more specific design, the reducer 6 has two input shafts, each of which is connected to a first drive motor 7. When working, any one or two of the first drive motors 7 can be started to control the movement of the gate 2.

[0042] Example 2

[0043] On the basis of the design of Example 1, as a consideration of the blowout preventer effect, as a more specific design, two blowout preventer channels 5 penetrating the outer shell 3 are provided in the main channel 4, and the two blowout preventer channels 5 are provided in parallel up and down.

[0044] On the basis of the above specific structural design, the blowout prevention channel 5 in this structure is designed according to the structure in Example 1. Then, in terms of structural design, the blowout preventer adopts two opening and closing channels. Usually, one of them is generally used. However, according to actual applications, in order to ensure the specific effect, two channels can be operated simultaneously according to actual conditions to further ensure the blowout prevention effect of the entire structure.

[0045] Example 3

[0046] A blowout prevention structure comprises at least two ram 2 blowout preventers as described in embodiment 1, wherein the ram 2 blowout preventers are assembled in series. According to the design of the structure, the upper and lower rams are sequentially connected in series to further complete the design of the entire blowout prevention.

[0047] In a more commonly used design, the blowout preventer structure includes at least one gate 2 blowout preventer as described in Example 1, and at least one annular blowout preventer, wherein the gate 2 blowout preventer and the annular blowout preventer are cross-arranged and assembled in series.

[0048] In the design of this structure, the series assembly is assembled through connecting flanges and assembled and fixed by bolts and nuts.

[0049] Example 4

[0050] In this embodiment, the structure of the annular blowout preventer in Embodiment 3 is further described. Specifically, an annular blowout preventer, such as Figure 4 and Figure 5As shown, it includes a base shell 97, the top of which is provided with a top cover 91 matching therewith, and a cavity is formed inside the top cover 91 and the base shell 97 after being assembled, and a pipe opening connected to the cavity is provided at the top of the top cover 91 and the bottom of the base shell 97, and the base shell 97 is provided with a piston 93, and a sealing core 92 is provided in the internal cavity of the top cover 91, and the piston 93 can be moved up and down by an electric drive device, and the sealing core 92 is located on the top or above the piston 93.

[0051] In this design, the design of this structure is different from that of the traditional structure in that this scheme adopts electric drive to realize the opening and closing of the blowout preventer. In specific operation, it can effectively realize the compactness of on-site components, and can also layout the drilling site more reasonably, further realizing the high-efficiency operation of the blowout preventer, and further solving the problems of traditional technology such as large device size, complex structure, high transportation and maintenance costs, slow response speed, and hydraulic oil leakage that pollutes the environment.

[0052] In the above-mentioned specific structural design, it is specifically described that the sealing core 92 is located at the top or above the piston 93. In this design, the sealing core 92 is a rubber core with a certain elasticity. In terms of the connection relationship, the sealing core 92 can be set at the top of the piston 93 and move with the piston 93. Of course, the connection adopts point connection, and a channel is reserved to maintain the through-continuity of the cavity; or, there is no connection relationship between the piston 93 and the sealing core 92, and the piston 93 is pushed up and naturally detaches from the top cover 91 under the action of gravity and pressure, thereby realizing the open state.

[0053] Based on the design of the above specific structure, as a more specific design, the outer edge of the sealing core 92 is conical or spherical, and matches with the inner surface of the top cover 91. In the design of this structure, the matching between the sealing core 92 and the top cover 91 can be effectively guaranteed through the design of this structure, and under the lifting force, the sealing effect of the entire structure can be effectively achieved.

[0054] Based on the above specific structural design, a further design is that under the action of the piston 93, when the piston 93 moves upward, the sealing core 92 can move upward; when the piston 93 moves downward, the sealing core 92 is not subject to the lifting force of the piston 93 or moves downward with the piston 93. Its action process can effectively ensure the realization of the entire function according to the above connection relationship and position relationship, thereby realizing the effect of the entire structure.

[0055] As a more specific design, in order to ensure the sealing effect of the entire structure and the effect of the blowout preventer in actual application, specifically, a mud guard ring 94 is provided in the cavity where the base shell 97 and the top cover 91 match and is located outside the piston 93, the top of the mud guard ring 94 matches the bottom of the top cover 91, and the bottom of the mud guard ring 94 cooperates with the piston 93. In the design of this structure, the sealing effect of the entire internal cavity can be guaranteed.

[0056] Based on the design of the above specific structure, as a more specific structural design, the electric drive device is a second drive motor 95, and the second drive motor 95 includes a stator 951 and a rotor 952. The stator 951 is fixedly connected to the base shell 97, and the rotor 952 drives the piston 93 to move up and down. In this embodiment, the rotor 952 and the piston 93 are matched through helical teeth to convert the rotational motion of the motor into the axial motion of the piston. In other embodiments, the rotor 952 and the piston 93 can be matched through other methods that can convert the rotational motion of the motor into the axial motion of the piston.

[0057] More specifically, the rotor is a hollow structure, which is sleeved on the outside of the piston 93 and assembled with the piston 93 through a transmission screw pair 916. The piston 93 can move up and down through the action of the transmission screw pair 916. In this embodiment, the piston 93 and the transmission screw pair 916 are matched by spiral teeth. In other embodiments, the transmission screw pair 916 and the piston 93 can be matched by other ways that can convert the rotational motion of the motor into the axial motion of the piston. The connection between the transmission screw pair 916 and the rotor 952 can be used to transmit circumferential torque. A second thrust bearing 96 is also provided below the rotor 952 where the transmission screw pair 916 is located. The provision of the second thrust bearing 96 withstands the reverse axial force of the piston moving upward, reduces the friction between the motor, the screw pair and the housing, and when there is a problem with the matching between the piston 93 and the screw pair 916, only the transmission screw pair 916 needs to be replaced or repaired, and the rotor of the motor does not need to be replaced or repaired, thereby reducing maintenance costs and maintenance time.

[0058] In this structure, the working principle of the motor is fully utilized, and the entire motor is effectively integrated into the structure of the blowout preventer. The design of the overall blowout preventer structure fully realizes the compact effect. Based on the traditional structural technology, the design of this structure does not require any additional external components, but only requires line layout. Therefore, the technical effects of high efficiency, compactness and oil leakage prevention are fully realized.

[0059] As a specific explanation, the design of the drive structure should also be involved in the traditional technology. The drive device is usually also a power source, but the power source is usually external. In this structure, the second drive motor 95 is directly integrated into a part of the entire structure, which not only saves additional installation space, but also integrates the structure of the entire blowout preventer to achieve a compact structure, which is very beneficial for transportation or installation, and further improves the installation effect to a great extent. However, its action principle is simple, and it is also simpler for later maintenance, and even more efficient and convenient for replacement.

[0060] Based on the above specific structural design, the base shell 97 is connected to the top cover 91 through studs, a main sealing ring 910 is provided at the connection between the base shell 97 and the top cover 91, a cap nut 98 is also provided at the top of the stud, and a nut sealing ring 911 is also provided between the cap nut 98 and the top cover 91.

[0061] As a sealing effect, further consideration is given to a first sealing ring 912 between the mud guard ring 94 and the piston 93, a second sealing ring 913 is provided between the mud guard ring 94 and the top cover 91, a third sealing ring 914 is provided between the mud guard ring 94 and the base shell 97, and a fourth sealing ring 915 is provided between the piston 93 and the base shell 97.

[0062] In terms of structural design, as a more specific design, a shackle 99 is provided above the top cover 91, connecting studs and nuts connected to the flange are provided above the top cover 91, and connecting studs and nuts connected to the flange are provided below the base shell 97.

[0063] The arrangement of the shackle 99 makes it more convenient to move the entire blowout preventer.

[0064] In summary:

[0065] 1. The gate blowout preventer of the present invention adopts an electric drive gate blowout preventer. Because the hydraulic system is eliminated, the floor space is reduced, the cost of mechanical maintenance and transportation is reduced, remote control can be realized, the safety and convenience of operation are improved, and digital control is realized. The electric drive is adopted, and it is easy to be equipped with an intelligent monitoring system, which can monitor the operating status of the equipment in real time, has a faster response speed, and can quickly close the wellhead when an abnormal situation is found.

[0066] 2. The gate blowout preventer and the blowout prevention structure using the gate blowout preventer of the present invention adopt an annular blowout preventer structure design that uses a motor to drive the up and down movement of the piston, thereby realizing the closing and opening of the rubber core to the wellhead. The electric-driven annular blowout preventer eliminates the hydraulic system, reduces the floor space, reduces the cost of mechanical maintenance and transportation, can be remotely controlled, improves the safety and convenience of operation, and is conducive to the realization of digital control. The use of electric drive makes it easy to equip an intelligent monitoring system, which can monitor the operating status of the equipment in real time, has a faster response speed, and can quickly close the wellhead when an abnormal situation is found;

[0067] 3. The gate blowout preventer and the blowout prevention structure using the gate blowout preventer of the present invention mainly adopt an electronic control method and control the opening and closing of the blowout preventer by driving a motor in terms of operation design. The working principle and requirements realize the optimization of the entire structure, and solve the problems of the prior art such as large device size, complex structure, high transportation and maintenance costs, slow response speed, and hydraulic oil leakage that pollutes the environment.

[0068] The present invention is not limited to the above-mentioned specific embodiments, but extends to any new features or any new combination disclosed in this specification, as well as any new method or process steps or any new combination disclosed.

Claims

1. A ram blowout preventer, characterized in that: It includes an outer shell, a main channel is arranged in the middle of the outer shell, a blowout prevention channel is arranged in the main channel, a gate mechanism is arranged in the blowout prevention channel, the gate mechanism includes a gate movable along the blowout prevention channel, an electric drive device is arranged at the outer end of the gate, and the electric drive device can be used to make the gate enter the main channel and then close the main channel.

2. A ram blowout preventer according to claim 1, characterized in that: The blowout prevention channel runs through the outer shell, and gate mechanisms are provided on both sides of the outer shell where the blowout prevention channel is located. The gates of the gate mechanisms on both sides can embrace the drill pipe or cut the drill pipe and extend to the middle of the main channel under the action of the electric drive device. The gates on both sides are matched to cut off the connection channel between the underground and the outside.

3. A ram blowout preventer according to claim 2, characterized in that: The main channel is provided with two blowout prevention channels penetrating the outer shell, and the two blowout prevention channels are arranged in parallel up and down.

4. A ram blowout preventer according to claim 2 or 3, characterized in that: The electric drive device comprises a reducer fixed on the outer shell, a first drive motor is fixedly arranged on the reducer, and the first drive motor drives the movement of the gate plate through the reducer.

5. A ram blowout preventer as claimed in claim 4, characterized in that: The reducer has at least one input shaft, each of which is connected to the output shaft of the first drive motor. The reducer is also provided with a connecting output shaft, which is connected to the gate plate and drives the gate plate to move.

6. A ram blowout preventer according to claim 5, characterized in that: The connecting output shaft is a hollow structure, and the connecting output shaft is sleeved on the gate plate and connected to the gate plate through a screw pair, and the movement of the gate plate is controlled by the screw pair.

7. A ram blowout preventer according to claim 6, characterized in that: Two first thrust bearings are also arranged between the inner side of the housing of the reducer and the gate plate.

8. A ram blowout preventer according to claim 5, characterized in that: The reducer has two input shafts, each of which is connected to a first drive motor. When working, any one or two of the first drive motors can be started to control the movement of the gate.

9. A blowout prevention structure, characterized in that: It comprises at least two ram blowout preventers according to any one of claims 1 to 8, wherein the ram blowout preventers are assembled in series; Or, it comprises at least one gate blowout preventer as described in any one of claims 1 to 7, and at least one annular blowout preventer, wherein the gate blowout preventer and the annular blowout preventer are cross-arranged and assembled in series.

10. A blowout prevention structure according to claim 9, characterized in that: The annular blowout preventer comprises a base shell, a top cover matching the base shell is arranged on the top of the base shell, a cavity is formed inside the top cover and the base shell after being assembled, a pipe opening connected to the cavity is arranged on the top of the top cover and the bottom of the base shell, a piston is arranged on the base shell, a sealing core is arranged in the cavity inside the top cover, the piston can be moved up and down by an electric drive device, and the sealing core is located on the top or above the piston.

11. A blowout prevention structure according to claim 10, characterized in that: A mud guard ring is also provided in the cavity where the base shell and the top cover match and on the outside of the piston. The top of the mud guard ring matches the bottom of the top cover, and the bottom of the mud guard ring cooperates with the piston.

12. A blowout prevention structure according to claim 11, characterized in that: The electric drive device is a second drive motor, which includes a stator and a rotor. The stator is fixedly connected to the base shell, and the rotor drives the piston to move up and down. The rotor is a hollow structure, which is sleeved on the outside of the piston and assembled with the piston through a transmission screw pair. The piston can move up and down through the action of the transmission screw pair.

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