Wellhead blowout preventer for pressurized operations

Abstract

This utility model relates to the field of petroleum machinery, specifically to a wellhead blowout preventer for pressurized operations. It includes a hydraulic lifting cylinder, a column, an upper crossbeam, a lower crossbeam, a movable crossbeam, movable load-bearing slips, movable top-prevention slips and a rotation device, an annular blowout preventer, a fixed slip assembly, a safety slip assembly, a balanced pressure relief valve assembly, and a gate blowout preventer assembly. The annular blowout preventer includes a lower housing, a middle housing, a top cover, a rubber core, a dust seal, and a piston. A first oil injection port is provided on the lower housing, and a second oil injection port is provided on the middle housing. The first oil injection port is connected to the bottom of the piston, and the second oil injection port is connected to the cavity. This utility model, through the coordinated control of the two oil injection ports, enables dynamic sealing adjustment of the annular blowout preventer, achieving axial + radial composite compression sealing, and enabling pressurized operation or zero-seal operation.

Description

Technical Field

[0001] This utility model relates to the field of petroleum machinery, specifically to a wellhead blowout preventer for pressurized operations. Background Technology

[0002] In oil and gas field maintenance operations, traditional well control techniques face significant technical bottlenecks. When dealing with pressurized oil and water wells, conventional operations require injecting high-density kill fluid to increase the wellbore fluid column pressure, thereby suppressing formation pressure to achieve a zero-pressure state at the wellhead and ensuring the safety of open-hole operations. However, this process presents three major challenges: first, it requires substantial human and material resources; second, well control fluid penetration can easily cause formation pore blockage, leading to reservoir contamination; and finally, it carries the dual risks of reduced production capacity and economic losses.

[0003] To address this industry pain point, innovative live-line operation equipment systems have been developed. However, existing technologies still face two major technical barriers: First, the equipment systems lack the core function of raising sucker rods under pressure, rendering them unsuitable for well conditions involving sucker rods. Second, limited by the design strength of the rotating flange, the pressure-bearing capacity of existing devices is insufficient to meet the demands of high-pressure conditions. These technical deficiencies severely restrict the application range of equipment in high-pressure well conditions, necessitating breakthroughs through structural optimization and technological upgrades. Utility Model Content

[0004] This section aims to outline certain aspects of embodiments of the present invention and briefly describe some preferred embodiments. Some simplifications or omissions may be made in this section, as well as in the abstract and title of this application, but such simplifications or omissions should not be used to limit the scope of the present invention.

[0005] The purpose of this invention is to overcome the problems existing in the prior art and provide a wellhead blowout preventer for pressurized operations. This device can lift the sucker rod under pressure, meet the operational requirements under high-pressure well conditions, and ensure the safety of the wellhead.

[0006] To solve the above technical problems, the present invention provides a wellhead blowout preventer for pressurized operations, comprising multiple hydraulic lifting cylinders. The hydraulic lifting cylinders are installed inside a column, and the upper and lower ends of the column are fixedly connected by an upper crossbeam and a lower crossbeam, respectively. The lifting piston of the hydraulic lifting cylinder supports the movable crossbeam, and the movable crossbeam is equipped with movable load-bearing slips, movable anti-overhead slips, and a rotation device. The lower crossbeam is equipped with, from top to bottom, an annular blowout preventer, a fixed slip assembly, a safety slip assembly, a balance pressure relief valve assembly, and a gate blowout preventer assembly.

[0007] The annular blowout preventer includes a lower housing, a middle housing, a top cover, a rubber core, a dust seal, and a piston. The piston has a Z-shaped cross-section. The rubber core is a cylindrical shape that is thicker at both ends and thinner in the middle. Its outer and inner surfaces are both arc-shaped curved surfaces with concave edges. Metal fixing plates are connected to the upper and lower ends of the rubber core. The upper and lower metal fixing plates of the rubber core abut against the piston and the top cover, respectively. There is a cavity between the outer surface of the rubber core and the middle housing. The lower housing and the middle housing are respectively provided with a first oil inlet and a second oil inlet. The first oil inlet communicates with the bottom of the piston, and the second oil inlet communicates with the cavity.

[0008] As an improvement of this utility model, an iron core is provided inside the rubber core. The iron core includes several sets of skeletons evenly distributed along the circumference of the rubber core, and each set of skeletons includes two hinged metal supports.

[0009] As a further improvement of this utility model, the two metal supports are of the same length, and the ends of the metal supports abut against the upper and lower metal fixing plates respectively.

[0010] As a further improvement of this utility model, the cross-section of the metal fixing plate is Z-shaped, and an arc groove is provided at the Z-shaped corner. The outline of the end of the metal support is arc-shaped, and the end of the metal support abuts against the arc groove of the metal fixing plate.

[0011] As a further improvement of this utility model, the thickness of the middle part of the core is greater than the thickness of its upper and lower ends.

[0012] As a further improvement of this utility model, two sealing elements are respectively provided between the metal fixing plate, the piston, and the top cover.

[0013] Compared with the prior art, this utility model achieves the following beneficial effects: 1. This utility model achieves dynamic sealing adjustment of the annular blowout preventer through the coordinated control of dual oil injection ports. Oil injection at the second oil injection port causes the rubber core to contract radially, forming an initial seal; oil injection at the first oil injection port drives the piston to push upward, achieving a composite compression seal of axial and radial forces, thereby realizing pressurized operation or zero sealing.

[0014] 2. The rubber core of this invention has several sets of metal support skeletons evenly distributed along its circumference embedded within it. These skeletons can contract synchronously through hinge points. During emergency oil injection, the piston forcibly lifts the rubber core, achieving overpressure locking of the metal skeleton hinge structure, thereby improving the sealing effect. Attached Figure Description

[0015] To more clearly illustrate the technical solutions of the embodiments of this utility model, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are merely some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. The drawings are for reference and illustration only and should not be used to limit this utility model. Wherein:

[0016] Figure 1 This is a front view of the blowout preventer device of this utility model used in operations involving lifting and lowering sucker rods;

[0017] Figure 2 This is a cross-sectional view of the blowout preventer device of this utility model used in operation with a pressurized sucker rod.

[0018] Figure 3 This is a perspective view of the blowout preventer device of this utility model for use in operations involving lifting and lowering sucker rods;

[0019] Figure 4 for Figure 2 Enlarged view of a central ring blowout preventer;

[0020] Figure 5 This is a magnified view of a ring-shaped blowout preventer with an iron core.

[0021] In the diagram: 1. Hydraulic lifting cylinder; 2. Column; 3. Upper crossbeam; 4. Lower crossbeam; 5. Moving load-bearing slip; 6. Moving anti-overhead slip; 7. Rotation device;

[0022] 8. Ring-shaped blowout preventer; 801. Lower housing; 802. Top cover; 803. Rubber core; 804. Dust seal; 805. Piston; 806. Metal fixing plate; 807. First oil inlet; 808. Second oil inlet; 809. Metal support; Middle housing 810;

[0023] 9 Fixed slip assembly; 10 Safety slip assembly; 11 Balanced pressure relief valve assembly; 12 Gate blowout preventer assembly; 13 Moving crossbeam. Detailed Implementation

[0024] In the following description of this utility model, the terms "upper", "lower", "front", "rear", "left", "right", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not mean that the device must have a specific orientation.

[0025] To make the technical means, creative features, achieved objectives, and effects of this utility model easier to understand, the present utility model is further described below with reference to specific illustrations. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the present utility model.

[0026] like Figures 1 to 5 As shown, the wellhead blowout preventer for pressurized operations of this utility model includes multiple hydraulic lifting cylinders 1. The hydraulic lifting cylinders 1 are installed inside a column 2, and the upper and lower ends of the column 2 are fixedly connected by an upper crossbeam 3 and a lower crossbeam 4, respectively. The lifting piston 805 of the hydraulic lifting cylinder 1 supports a movable crossbeam 13. A rotating device 7 is installed at the center of the movable crossbeam 13. A movable load-bearing slip 5 is installed above the rotating device 7, and a movable anti-overhead slip 6 is installed below the rotating device 7. From top to bottom, the lower crossbeam 4 is equipped with an annular blowout preventer 8, a fixed slip assembly 9, a safety slip assembly 10, a balance pressure relief valve assembly 11, and a gate blowout preventer assembly 12.

[0027] The fixed slip assembly 9 is mainly used in conjunction with the movable load-bearing slip 5 and the movable anti-overhead slip 6 to complete tubing tripping operations. In cases of heavy tubing, it prevents the tubing from falling into the well; in cases of light tubing, it prevents the tubing from flying out of the wellhead. The fixed slip assembly 9 is a self-tightening slip, clamping the tubing through a hydraulic cylinder. When the slip seat inside the slip engages the tubing, the greater the pressure on the tubing due to the conical surface of the slip seat, the greater the clamping force, effectively securing the tubing and preventing it from loosening.

[0028] The movable slip assembly is used in conjunction with the fixed slip assembly 9. The movable slip assembly is installed on the movable crossbeam 13. The upper side of the movable crossbeam 13 has movable load-bearing slips 5, and the lower side has movable anti-overhead slips 6. They rise or fall with the movable crossbeam 13, and can rotate forward, reverse or stop through the hydraulic motors and brake devices on both sides. In conjunction with the fixed slips, they realize the inverting column action.

[0029] The hydraulic lifting cylinder 1 supports the movable crossbeam 13 and its movable slip assembly, enabling the tubing to be pulled out of the wellhead or pushed down into the well under well pressure. Both the upper and lower ends of the hydraulic lifting cylinder 1 are equipped with hydraulic buffer structures. The upper part of the piston rod of the hydraulic lifting cylinder 1 is a tapered shaft end, facilitating alignment and disassembly. The support flange of the hydraulic lifting cylinder 1 is located at the top of the cylinder and connected to the upper crossbeam 3, using a suspended installation. This structure provides a reasonable stress distribution, preventing the cylinder from easily bending under stress. When the wellbore pressure exceeds the lifting or downward thrust, a balanced pressure relief valve assembly 11 is used to stabilize the cylinder speed, preventing the hydraulic cylinder from becoming uncontrollable due to excessive load.

[0030] The movable load-bearing slip 5 and the movable anti-jacking slip 6 are connected to the movable crossbeam 13 via a hydraulic rotation device 7. When raising or lowering the oil pipe, the slips are closed to lock the oil pipe, and then the oil pipe is raised or lowered by the lifting of the hydraulic lifting cylinder 1. The rotation device 7 relies on the rotation of the hydraulic motors on both sides of the crossbeam and achieves forward and reverse rotation by switching the oil circuit directional valve, so that the oil pipe can rotate in either light or heavy pipe string mode.

[0031] The upper crossbeam 3 and the lower crossbeam 4 are connected and fixed by the column 2 and flange. Four wellhead mechanical spiral outriggers are installed at the lower part of the column 2. These wellhead mechanical spiral outriggers are the main load-bearing components. During operation, the lifting force of the tubing, the downward pressure, and the weight of the equipment are all transferred to the ground foundation through the wellhead mechanical spiral outriggers.

[0032] The pressure relief valve assembly 11 is mainly used to balance or release the pressure between the upper and lower working gate blowout preventers when reversing tool strings or tubing couplings. When the well pressure is low and the annular blowout preventer 8 is in operation, the pressure relief section can also relieve well pressure and protect personnel. The function of the balancing valve and the pressure relief valve is to balance or release the pressure between the upper and lower gates, thereby protecting the gate blowout preventer components and personnel.

[0033] The gate blowout preventer assembly 12 includes a lower semi-sealed gate blowout preventer, a safety semi-sealed gate blowout preventer, and a full-sealed gate blowout preventer. The gate blowout preventer assembly 12 is a key component of the well control system, primarily used to control wellhead pressure during drilling, well workover, and well testing, effectively preventing blowout accidents and ensuring safe operation. When drill strings are present in the well, a semi-sealed gate (also known as a semi-sealed gate blowout preventer) of the appropriate size can be used to seal the annulus between the casing and the drill strings; when no drill strings are present, a full-sealed gate (also known as a full-sealed gate blowout preventer) can be used to completely seal the wellhead. In emergencies, a shear gate can be used to cut the tubing string in the well and completely seal the wellhead.

[0034] like Figure 3As shown, the annular blowout preventer 8 includes a lower housing 801, a middle housing 810, a top cover 802, a rubber core 803, a dust seal 804, and a piston 805. The lower housing 801 and the middle housing 810 are connected by bolts, and the top cover 802 is installed on the upper port of the middle housing 810. The piston 805 has a Z-shaped cross-section. The rubber core 803 is a cylindrical shape that is thicker at both ends and thinner in the middle. Its outer and inner surfaces are both arc-shaped curved surfaces, and the arc edges are concave inward. Metal fixing plates 806 are connected to the upper and lower ends of the rubber core 803, and the upper and lower metal fixing plates 806 abut against the piston 805 and the top cover 802, respectively. There is a cavity between the outer surface of the rubber core 803 and the middle housing 810. The lower housing 801 and the middle housing 810 are respectively provided with a first oil inlet 807 and a second oil inlet 808. The first oil inlet 807 is connected to the bottom of the piston 805, and the second oil inlet 808 is connected to the cavity.

[0035] During live operation, hydraulic oil is injected into the second injection port 808 of the annular blowout preventer 8. The hydraulic oil fills the cavity between the rubber core 803 and the middle housing 810, squeezing the rubber core 803 inward to seal the wellbore pressure. The rubber core 803 is made of natural rubber and can seal tools of any shape (such as angular drill pipe, drill pipe, drill pipe joint, drill collar, casing, cable, etc.). The hydraulic system can maintain a constant pressure when the outer diameter of the tubing changes. When dealing with tools of different diameters, hydraulic oil can be injected appropriately into the first injection port 807 to appropriately raise the height of the piston 805, and in conjunction with the hydraulic oil injected into the second injection port 808, to ensure that the rubber core 803 maintains close contact with the tool, thereby achieving live operation.

[0036] In an emergency, hydraulic oil can be injected into the first oil inlet 807. At this time, the piston 805 rises, squeezing the rubber core 803 inward and upward. The rubber core 803 is squeezed in the vertical and external directions, thus contracting inward and ultimately achieving zero sealing in an emergency.

[0037] In practical applications, such as Figure 4 As shown, an iron core is installed inside the rubber core 803. The iron core includes several sets of skeletons evenly distributed along the circumference of the rubber core 803, and each set of skeletons includes two hinged metal supports 809. When the piston 805 rises, the hinges of the metal supports 809 contract inward, thereby providing a stronger contraction force and better realizing pressurized operation.

[0038] In practical applications, the two metal supports 809 are of the same length, and the ends of the metal supports 809 abut against the upper and lower metal fixing plates 806 respectively. The metal supports 809 and the metal fixing plates 806 are in rigid contact, ensuring that the multiple sets of metal supports 809 on the circumference can bend synchronously when the piston 805 rises and falls, thereby avoiding uneven deformation in various places.

[0039] In practical applications, the metal fixing plate 806 has a Z-shaped cross-section, with an arc groove at the inner corner of the Z-shaped bend. The end of the metal support 809 has an arc-shaped profile. The end of the metal support 809 abuts against the arc groove of the metal fixing plate 806. The arc groove serves to limit the movement of the metal support 809, but does not restrict its free rotation. Moreover, no additional assembly is required during installation to allow the metal support 809 to rotate freely within a limited range.

[0040] In practical applications, the thickness of the middle part of the rubber core 803 is greater than the thickness of its top and bottom ends. Because the middle part of the rubber core 803 comes into contact with the tool and is prone to wear, sufficient rubber allowance needs to be left.

[0041] In summary, the wellhead blowout preventer for pressurized operations described in this utility model achieves dynamic seal adjustment through coordinated control of dual injection ports and annular blowout preventer 8. Injecting oil through the second injection port 808 causes the rubber core 803 to contract radially, forming an initial seal; injecting oil through the first injection port 807 drives the piston 805 upward, achieving a composite compression seal of axial and radial forces, thereby enabling pressurized operation or zero-seal operation.

[0042] The above description is merely a preferred embodiment of the present utility model, showing and describing the basic principles, main features, and advantages of the present utility model. It is not intended to limit the scope of patent protection of the present utility model. Those skilled in the art should understand that the present utility model is not limited to the above embodiments. In addition to the above embodiments, the present utility model may have other implementations without departing from the spirit and scope of the present utility model. Various changes and improvements to the present utility model are also possible. All technical solutions formed by equivalent substitutions or equivalent transformations fall within the scope of protection claimed by the present utility model. The scope of protection claimed by the present utility model is defined by the appended claims and their equivalents. Technical features not described in the present utility model can be implemented by or using existing technology, and will not be elaborated here.

Claims

1. A blowout preventer for wellhead operations under pressure, characterized in that: It includes multiple hydraulic lifting cylinders (1), which are installed inside the column (2). The upper and lower ends of the column (2) are fixedly connected by the upper crossbeam (3) and the lower crossbeam (4) respectively. The lifting piston (805) of the hydraulic lifting cylinder (1) supports the moving crossbeam (13). The moving crossbeam (13) is equipped with a moving load-bearing slip (5), a moving anti-top slip (6) and a rotating device (7). The lower crossbeam (4) is equipped with an annular blowout preventer (8), a fixed slip assembly (9), a safety slip assembly (10), a balance pressure relief valve assembly (11), and a gate blowout preventer assembly (12) in sequence from top to bottom. The annular blowout preventer (8) includes a lower housing (801), a middle housing (810), a top cover (802), a rubber core (803), a dustproof ring (804), and a piston (805). The piston (805) has a Z-shaped cross-section. The rubber core (803) is a cylindrical shape that is thicker at both ends and thinner in the middle. Its outer and inner surfaces are both arc-shaped curved surfaces with concave edges. The rubber core (803) is connected to metal fixing plates (806) at both ends. The upper and lower metal fixing plates (806) of the core (803) abut against the piston (805) and the top cover (802) respectively. There is a cavity between the outer side of the core (803) and the middle shell (810). The lower shell (801) and the middle shell (810) are respectively provided with a first oil inlet (807) and a second oil inlet (808). The first oil inlet (807) is connected to the bottom of the piston (805), and the second oil inlet (808) is connected to the cavity.

2. The wellhead blowout preventer for pressurized operations according to claim 1, characterized in that: The core (803) contains an iron core, which includes several sets of skeletons evenly distributed along the circumference of the core (803). Each set of skeletons includes two hinged metal supports (809).

3. The wellhead blowout preventer for pressurized operations according to claim 2, characterized in that: The two metal supports (809) have the same length, and the ends of the metal supports (809) abut against the upper and lower metal fixing plates (806) respectively.

4. A blowout preventer for wellhead operations under pressure as described in claim 3, characterized in that: The metal fixing plate (806) has a Z-shaped cross section and an arc groove is provided at the Z-shaped corner. The end of the metal support (809) has an arc-shaped profile and the end of the metal support (809) abuts against the arc groove of the metal fixing plate (806).

5. A blowout preventer for wellhead operations under pressure according to claim 1, characterized in that: The thickness of the core (803) in the middle is greater than the thickness of its upper and lower ends.

6. A blowout preventer for wellhead operations under pressure according to claim 1, characterized in that: Two seals are provided between the metal fixing plate (806), the piston (805), and the top cover (802).

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