Annular blowout preventer and working method thereof

Abstract

The invention discloses an annular blowout preventer and a working method thereof, and belongs to the technical field of petroleum drilling equipment. The device comprises a base shell, a top cover matched with the base shell is arranged at the top of the base shell, a containing cavity is formed in the base shell after the top cover and the base shell are assembled, pipe openings communicated with the containing cavity are formed in 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 containing cavity in the top cover, and the piston is arranged in the sealing core. The piston can move up and down through the electric driving device, and the sealing core is located at the top of the piston or above the piston. The electric control mode is mainly 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 an annular blowout preventer and a working method thereof, belonging to the technical field of oil drilling equipment. Background Art

[0002] BOPs are used to close the wellhead during oil drilling to prevent blowout accidents. 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 drilling tool, thereby sealing the wellhead. When there is no drilling tool at the wellhead, the rubber core is squeezed toward the center of the wellhead until it fills the entire wellhead channel to prevent 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 is opened. 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 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

[0003] The purpose of the present invention is to provide an annular blowout preventer and a working method thereof in view of the above-mentioned problems, which have compact structure, fast response speed, safety and high efficiency, and add 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.

[0004] The technical solution adopted by the present invention is as follows: An 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, 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.

[0005] Furthermore, the outer edge of the sealing core is conical or spherical and matches with the inner surface of the top cover.

[0006] Furthermore, under the action of the piston, when the piston moves upward, the sealing core moves upward with the lifting of the piston; when the piston moves downward, the piston separates from the sealing core, and the sealing core moves downward under the action of its own weight, or the sealing core is connected to the top of the piston and moves downward with the piston.

[0007] 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.

[0008] Furthermore, the electric drive device is a 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.

[0009] Furthermore, the rotor is a hollow structure, which is sleeved on the outside of the piston and assembled with the piston through a spiral pair, and the piston can move up and down through the action of the spiral pair.

[0010] Furthermore, a thrust bearing is provided below the rotor where the spiral pair is located.

[0011] Furthermore, the base shell and the top cover are connected by studs, a main sealing ring is provided at the connection between the base shell and the top cover, a cap nut is also provided on the top of the stud, and a nut sealing ring is also provided between the cap nut and the top cover.

[0012] Furthermore, a first sealing ring is provided between the mud guard ring and the piston, a second sealing ring is provided between the mud guard ring and the top cover, a third sealing ring is provided between the mud guard ring and the base shell, and a fourth sealing ring is provided between the piston and the base shell.

[0013] A working method of an annular blowout preventer is applied to the above annular blowout preventer, wherein the forward and reverse rotation of a driving motor is controlled by an external control system. When the driving motor rotates forward, the piston is driven to move upward by a spiral pair, and the piston squeezes a sealing core, so that the sealing core moves toward the center of a wellhead along the inner surface of a top cover and seals the wellhead passage, thereby closing the wellhead. When the wellhead needs to be opened, the control system controls the driving motor to reverse, the spiral pair drives the piston to move downward, the piston no longer squeezes the sealing core, the sealing core expands outward away from the center of the wellhead, and the wellhead is opened.

[0014] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are: 1. An annular blowout preventer of the present invention uses a motor to drive the piston to move up and down, 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 digital control. The electric drive 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 open and close the wellhead more accurately, and can quickly close the wellhead when an abnormal situation is found.

[0015] 2. The working method of an annular blowout preventer of the present invention mainly adopts an electronic control method and controls the opening and closing of the blowout preventer by driving a motor in terms of operation design. Its 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

[0016] The present invention will now be described by way of example with reference to the accompanying drawings, in which: Figure 1 It is a structural schematic diagram of the present invention.

[0017] Figure 2 This is an enlarged schematic diagram of point A.

[0018] Markings in the figure: 1-top cover, 2-sealing core, 3-piston, 4-mud guard ring, 5-driving motor, 51-stator, 52-rotor, 6-thrust bearing, 7-base housing, 8-cap nut, 9-shackle, 10-main sealing ring, 11-nut sealing ring, 12-first sealing ring, 13-second sealing ring, 14-third sealing ring, 15-fourth sealing ring, 16-screw pair. DETAILED DESCRIPTION

[0019] 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.

[0020] 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.

[0021] Example 1 An annular blowout preventer, such as Figure 1 and Figure 2 As shown, it includes a base shell 7, the top of which is provided with a top cover 1 matching therewith, and a cavity is formed inside the top cover 1 and the base shell 7 after being assembled, and a pipe opening connected to the cavity is provided at the top of the top cover 1 and the bottom of the base shell 7, and the base shell 7 is provided with a piston 3, and a sealing core 2 is provided in the internal cavity of the top cover 1, and the piston 3 can be moved up and down by an electric drive device, and the sealing core 2 is located on the top or above the piston 3.

[0022] 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.

[0023] In the above-mentioned specific structural design, it is specifically described that the sealing core 2 is located at the top or above the piston 3. In this design, the sealing core 2 is a rubber core with a certain elasticity. In terms of the connection relationship, the sealing core 2 can be set at the top of the piston 3 and move with the piston 3. 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 3 and the sealing core 2, and the piston 3 is pushed up and naturally detaches from the top cover 1 under the action of gravity and pressure, thereby realizing the open state.

[0024] Based on the design of the above specific structure, as a more specific design, the outer edge of the sealing core 2 is conical or spherical, and matches with the inner surface of the top cover 1. In the design of this structure, the matching between the sealing core 2 and the top cover 1 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.

[0025] Based on the above specific structural design, a further design is that under the action of the piston 3, when the piston 3 moves upward, the sealing core 2 moves upward with the lifting of the piston 3; when the piston 3 moves downward, the piston 3 is separated from the sealing core, and the sealing core 2 moves downward under the action of its own weight, or the sealing core 2 is connected to the top of the piston 3 and moves downward with the piston 3. 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.

[0026] 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 4 is provided in the cavity where the base shell 7 and the top cover 1 match and is located outside the piston 3, the top of the mud guard ring 4 matches the bottom of the top cover 1, and the bottom of the mud guard ring 4 cooperates with the piston 3. In the design of this structure, the sealing effect of the entire internal cavity can be guaranteed.

[0027] Based on the design of the above specific structure, as a more specific structural design, the electric drive device is a drive motor 5, and the drive motor 5 includes a stator 51 and a rotor 52. The stator 51 is fixedly connected to the base shell 7, and the rotor 52 drives the piston 3 to move up and down. In this embodiment, the rotor 52 and the piston 3 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 52 and the piston 3 can be matched through other methods that can convert the rotational motion of the motor into the axial motion of the piston.

[0028] More specifically, the rotor 52 is a hollow structure, which is sleeved on the outside of the piston 3 and assembled with the piston 3 through the spiral pair 16. The piston 3 can move up and down through the action of the spiral pair 16. In this embodiment, the piston 3 and the spiral pair 16 are matched by spiral teeth. In other embodiments, the spiral pair 16 and the piston 3 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 spiral pair 16 and the rotor 52 can be used to transmit circumferential torque. A thrust bearing 6 is also provided below the rotor 52 where the spiral pair 16 is located. In this structure, the closing or opening of the wellhead is achieved by relying on the cooperation of the rotor 52, the spiral pair 16 and the piston 3. The design of this structure is more accurate than the control of the hydraulic cylinder. The setting of the thrust bearing 6 bears the reverse axial force of the upward movement of the piston 3, reduces the friction between the drive motor 5, the spiral pair 16 and the base shell 7, and when there is a problem in the coordination between the piston 3 and the spiral pair 16, only the spiral pair 16 needs to be replaced or repaired, and there is no need to replace or repair the rotor of the motor, thereby reducing maintenance costs and reducing maintenance time.

[0029] 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.

[0030] 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 drive motor 5 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.

[0031] Based on the above specific structural design, the base shell 7 is connected to the top cover 1 through studs, a main sealing ring 10 is provided at the connection between the base shell 7 and the top cover 1, a cap nut 8 is also provided at the top of the stud, and a nut sealing ring 11 is also provided between the cap nut 8 and the top cover 1.

[0032] As a sealing effect, further consideration is given to a first sealing ring 12 between the mud guard ring 4 and the piston 3, a second sealing ring 13 is provided between the mud guard ring 4 and the top cover 1, a third sealing ring 14 is provided between the mud guard ring 4 and the base shell 7, and a fourth sealing ring 15 is provided between the piston 3 and the base shell 7.

[0033] In terms of structural design, as a more specific design, a shackle 9 is provided above the top cover 1, connecting studs and nuts connected to the flange are provided above the top cover 1, and connecting studs and nuts connected to the flange are provided below the base shell 7.

[0034] The arrangement of the shackle 9 makes it more convenient to move the entire blowout preventer.

[0035] Example 2 Based on the design of Example 1, a working method of an annular blowout preventer is provided, which is as follows: The forward and reverse rotation of the driving motor 5 is controlled by an external control system (the control system already exists at the drilling site). When the driving motor 5 rotates forward, the piston 3 is driven to move upward through the screw pair, and the piston 3 squeezes the sealing core 2, so that the sealing core 2 moves along the inner surface of the top cover 1 toward the center of the wellhead and seals the wellhead channel, thereby closing the wellhead; When the wellhead needs to be opened, the control system controls the driving motor 5 to reverse, the screw pair drives the piston 3 to move downward, the sealing core 2 expands outward and leaves the center of the wellhead, and the wellhead is opened.

[0036] In summary: 1. The annular blowout preventer of the present invention uses a motor to drive the piston to move up and down, 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 realize remote control, improves the safety and convenience of operation, and is conducive to automatic control. The electric drive 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.

[0037] 2. The working method of an annular blowout preventer of the present invention mainly adopts an electronic control method and controls the opening and closing of the blowout preventer by driving a motor in terms of operation design. Its 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.

[0038] The present invention is not limited to the aforementioned 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. An annular blowout preventer, Features: It 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.

2. The annular blowout preventer according to claim 1, Features: The outer edge of the sealing core is conical or spherical and matches with the inner surface of the top cover.

3. The annular blowout preventer according to claim 1 or 2, Features: Under the action of the piston, when the piston moves upward, the sealing core moves upward with the lifting of the piston; when the piston moves downward, the piston is separated from the sealing core, and the sealing core moves downward under the action of its own weight, or the sealing core is connected to the top of the piston and moves downward with the piston.

4. The annular blowout preventer according to claim 3, Features: 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.

5. The annular blowout preventer according to claim 1, Features: The electric drive device is a 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.

6. The annular blowout preventer according to claim 5, Features: The rotor is a hollow structure, which is sleeved on the outer side 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.

7. The annular blowout preventer according to claim 6, Features: A thrust bearing is also provided below the rotor where the helical pair is located.

8. The annular blowout preventer according to claim 4, Features: The base shell and the top cover are connected through studs, a main sealing ring is arranged at the connection between the base shell and the top cover, a cap nut is arranged on the top of the stud, and a nut sealing ring is arranged between the cap nut and the top cover.

9. The annular blowout preventer according to claim 4, Features: A first sealing ring is arranged between the mud guard ring and the piston, a second sealing ring is arranged between the mud guard ring and the top cover, a third sealing ring is arranged between the mud guard ring and the base shell, and a fourth sealing ring is arranged between the piston and the base shell.

10. A method for operating an annular blowout preventer, applied to the annular blowout preventer according to any one of claims 1 to 9, Features: The forward and reverse rotation of the driving motor is controlled by an external control system. When the driving motor rotates forward, the piston is driven to move upward through the spiral pair, and the piston squeezes the sealing core, so that the sealing core moves toward the center of the wellhead along the inner surface of the top cover and seals the wellhead channel, thereby closing the wellhead; When the wellhead needs to be opened, the control system controls the driving motor to reverse, the spiral pair drives the piston to move downward, the piston no longer squeezes the sealing core, the sealing core expands outward away from the center of the wellhead, and the wellhead is opened.

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