Shearing and sealing integrated well repair blowout preventer

Abstract

The invention relates to the technical field of petroleum engineering, and provides a shearing and sealing integrated well repair blowout preventer which comprises a shell 6, a shearing flashboard 7 and a flashboard feeding mechanism used for driving the shearing flashboard 7, the shell 6 is in a hollow cross shape, and a sucker rod passes through the drift diameter of the upper side and the drift diameter of the lower side of the cross. A pair of coupled shear flashboards 7 is symmetrically arranged in the left drift diameter and the right drift diameter respectively and comprises an upper shear flashboard 71 and a lower shear flashboard 72 which are coupled, sheared and bent, and the upper shear flashboard 71 and the lower shear flashboard 72 are driven by a flashboard feeding mechanism to shear and bend a sucker rod inwards in a left-right V shape, so that well shut-in and flow control are achieved. The bending groove design is introduced into the shearing flashboard structure, the flashboard can bend an oil pipe while shearing the oil pipe, blowout high-pressure fluid in a pipe column is preliminarily controlled, and the water hammer impact and flow-induced vibration phenomena are effectively relieved; the flow guide mechanism balances the pressure of the upper part and the lower part in the vertical drift diameter, and the well opening difficulty is reduced.

Description

Technical Field

[0001] The invention relates to the technical field of petroleum engineering, and in particular to a well repair blowout preventer with integrated shear seal. Background Art

[0002] The safe and efficient development of oil and gas resources is related to the national energy strategic security. In the emergency situation of the oil field site's downhole pressure out of control, the gate blowout preventer is mainly relied on to quickly close the wellhead, prevent blowouts, protect the safety of on-site personnel and prevent environmental pollution. Therefore, structural safety and no leakage in the seal are the key technical indicators for evaluating the performance of the blowout preventer.

[0003] Oil production operations are usually carried out under harsh environmental conditions, such as high temperature, high pressure, corrosive substances, etc., and the downhole pressure increases with the depth, which brings serious safety risks to the wellhead workers. In the development and exploitation of oil and gas, it is necessary to pierce the deep formation structure so that the collection device can be lowered into the high-pressure oil and gas reservoir. However, in the formation, when the underground structure containing high-pressure fluid is pierced, the local pressure of the fluid may increase rapidly, and even completely exceed the hydraulic head or water pressure head of the mud located above it, so that the mud in the well will surge and may eventually lead to a well surge or blowout from the drilling mud. Once a blowout occurs, it often causes serious consequences such as damage to drilling equipment and instruments, destruction of oil and gas resources, pollution of the local natural environment, scrapping of oil and gas wells, and even threats to the lives of drilling workers. In order to prevent catastrophic events, well control equipment, especially well control blowout preventers, must be installed at the wellhead.

[0004] Reasonable design of blowout preventer can not only ensure the safety of operators, but also effectively protect equipment from damage caused by oil injection, extend the service life of petroleum equipment, reduce equipment maintenance costs, and reduce costs and profits for oil companies.

[0005] Well control blowout preventers mainly include annular blowout preventers, gate blowout preventers, and rotary blowout preventers. According to the type of use, gate blowout preventers can be divided into fully enclosed gate blowout preventers ( Figure 1a )、Pipe gate blowout preventer( Figure 1b ) and shear ram blowout preventer ( Figure 1c ) There are three types. Among them, the traditional gate blowout preventer does not have sealing ability and needs to be used in a blowout preventer group with other sealing types of blowout preventers. However, since the high-pressure fluid water hammer effect and the vibration caused by fluid-solid coupling under abnormal blowout conditions during the well repair process are not considered, the shear gate dislocation leads to leakage in the blowout preventer group.

[0006] The existing publication number is CN111155956A, which discloses a double-piston composite double-gate blowout preventer and a method for hanging a tubing and sealing a wellhead. The blowout preventer includes a shell, in which a shear full-seal gate assembly for closing the wellhead after cutting the tubing and a hanging half-seal gate assembly for hanging the tubing and sealing the wellhead are symmetrically installed from top to bottom. The shear full-seal gate assembly is connected to a first drive device, and the hanging half-seal gate assembly is connected to a second drive device, and the second drive device includes a hanging piston drive mechanism and a half-seal piston drive mechanism; the hanging half-seal gate assembly includes: a hanging gate body, in which a half-seal front seal and a floating slip are installed; the half-seal front seal is connected to the half-seal piston drive mechanism, and the slip is connected to the hanging piston drive mechanism. The shear gate of the well control blowout preventer in this technology is designed based on the static theory, without considering the high-pressure fluid water hammer impact in the case of sudden blowout, the dynamic impact and vibration load caused by fluid-solid coupling, which easily leads to the failure of the shear gate to shut in the field due to the dislocation. At the same time, the existing shear blowout preventer has no sealing function and needs to be used in combination with multiple blowout preventers of other sealing types. The blowout preventer groups stacked in sequence at the wellhead will form a tower several meters or even more than ten meters high, which increases the difficulty of on-site engineering operations. Since the blowout preventer combination is mainly aimed at the problem of high pressure in deep wells, and in well repair operations, the pressure in the well has been significantly reduced due to continuous mining, continuing to use multiple blowout preventer combinations will cause excess performance and increase the development cost of the oil field. Summary of the invention

[0007] In order to overcome or alleviate one or more of the above technical problems, the present invention aims to provide a well repair blowout preventer with integrated shear seal, the structural design of which takes into account the water hammer impact and flow-induced vibration factors of high-pressure fluid under abnormal blowout conditions.

[0008] The present invention provides the following technical solutions:

[0009] A well repair blowout preventer with integrated shear seal comprises a housing (6), a shear gate (7) and a gate feed mechanism for driving the shear gate (7); the housing (6) is cross-shaped and hollow; sucker rods are arranged in the upper and lower side passages of the cross; a pair of coupled shear gates (7) are symmetrically arranged in the left and right side passages; the shear gates (7) comprise an upper shear gate (71) and a lower shear gate (72) coupled to each other for shearing and bending; the upper shear gate (71) and the lower shear gate (72) are driven by the gate feed mechanism to shear and bend the sucker rods inwardly in a V-shape on the left and right sides, thereby completely sealing the well and controlling the flow during the well repair.

[0010] According to some embodiments, the upper shear gate (71) and the lower shear gate (72) are both cylindrical; the upper shear gate (71) is provided with a first shearing blade (713) facing upward in the shearing direction, is concave in the middle, and is provided with a first bending portion (712) at the bottom; the top of the gate body is provided with a first sealing groove (711) facing inward, the bottom is provided with a first guide groove (714) facing the shearing direction, and a first piston clamping groove (715) is provided toward the outward end; the lower shear gate (72) is concave in the shearing direction, is provided with a second shearing blade (723) in the middle, and is provided with a second bending portion (722) at the bottom; the top of the gate body is provided with a second sealing groove (721) facing inward, the bottom is provided with a second guide groove (724) facing the shearing direction, and a second piston clamping groove (725) is provided toward the outward section.

[0011] According to some embodiments, the first shearing edge (713) and the second shearing edge (723) both form a V-shaped opening angle when viewed from above, and the angle of the V-shaped opening angle is 165°; the inclination angle of the blade of the first shearing edge (713) and the second shearing edge (723) is 130°, and they are concave and convex corresponding.

[0012] According to some embodiments, a single gate feed mechanism includes a piston (9) coupled to a first piston slot (715) of the upper shear gate (71) or a second piston slot (725) of the lower shear gate (72); the piston (9) is connected outwardly to a transmission shaft (3); an axial bearing (11) is axially provided on the transmission shaft (3); and the outer end of the transmission shaft (3) is driven manually or electrically to drive the piston (3) to drive the upper shear gate (71) or the lower shear gate (72) to perform inward shearing movement.

[0013] According to some embodiments, the upper and lower shear gates are provided with a sealing assembly for top sealing and transmission sealing and the gate feed mechanism is provided with the sealing assembly, the sealing assembly includes a bending seal and a transmission seal, the bending seal coupling is arranged in the first sealing groove (711) and the second sealing groove (721); the transmission seal includes a V-shaped sealing ring (13) arranged between the piston (9) and the piston housing (5), a trapezoidal sealing ring (15) arranged at the connection between the bearing housing (4) of the axial bearing (11), and a rectangular sealing ring (16) arranged between the bearing housing (4) and the piston housing (5).

[0014] According to some embodiments, the material of the bend seal is selected from nitrile rubber.

[0015] According to some embodiments, a vertically arranged flow guiding mechanism (25) is provided on one side of the cross of the shell (6), and the flow guiding mechanism (25) includes a control valve (24) on one side and a bypass joint (22) surrounded by a valve seat (21) on the other side, and the control valve (24) and the bypass joint (22) are connected through a flow guiding pipe (23), and the bypass joint (22) and the control valve (24) are connected toward the inside of the shell (6) to form a flow guiding port (26).

[0016] Compared with the prior art, the present invention has the following beneficial effects:

[0017] (1) The present invention introduces a bending groove design based on the existing shear gate structure, so that the gate can bend the sucker rod string while shearing, preliminarily controlling the blowout high-pressure fluid in the string, alleviating water hammer impact and flow-induced vibration phenomena, and only using one set of blowout preventers provided by the present invention to deal with abnormal blowouts.

[0018] (2) The present invention proposes a relatively simple shear gate blade design structure model, that is, the gate blade is divided into a "V"-shaped opening angle and a blade inclination angle, and the modified yield stress of the sucker rod is applied to the blade for simulation, so as to obtain a relatively ideal "V"-shaped opening angle and blade inclination angle, so as to achieve a relatively ideal shear effect.

[0019] (3) The present invention reduces the difficulty of processing the integrated shear seal structure of the blowout preventer by simplifying the design. The design uses fewer parts and structures with different rubber bodies, as well as innovative combinations of rubber bodies, to achieve the shear, seal and support functions of the oil pipe during well repair operations.

[0020] In addition, the present invention can quickly complete the shearing of the oil pipe and the sealing of the wellhead under low formation pressure, preliminarily control the fluid in the oil pipe, and effectively reduce the water hammer effect and fluid-solid coupling. The technology also reduces the impact force of the fluid on the shear gate, ensuring the stability of the shearing process.

[0021] In terms of the transmission mechanism of the gate, the present invention adopts a manual drive mode and introduces a new "V" opening angle and blade surface inclination design to improve the shearing effect. The fixing method of the transmission mechanism adopts a combination of screws and threads, replacing the traditional all-screw fixing method, which not only reduces the difficulty of installation, but also improves the installation efficiency.

[0022] (4) The flow guide device provided by the present invention is intended to adjust the pressure balance in the vertical path of the blowout preventer during the well opening process, thereby reducing the difficulty of well opening and protecting the internal structure of the equipment. In the well sealing state, the well opening operation becomes complicated due to the large pressure difference between the upper and lower gate plates in the vertical path. This problem can be effectively alleviated by the flow guide mechanism of the present invention.

[0023] (5) The present invention has a simple internal structure, few parts, and the gate body is easy to replace. The main vulnerable parts, the gate, the transmission shaft, and the piston, are all made of rotating bodies, which are simple to process and easy to promote. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1a The invention relates to a fully enclosed gate blowout preventer provided in the background technology of the present application.

[0025] Figure 1b The invention relates to a pipe gate blowout prevention device provided in the background technology of the present application.

[0026] Figure 1c The invention relates to a shear ram blowout preventer provided in the background technology of the present application.

[0027] Figure 2 An overall schematic diagram of a well repair blowout preventer with integrated shear seal provided in an embodiment of the present application.

[0028] Figure 3a A top view and a cross-sectional view of the upper shear gate provided in an embodiment of the present application.

[0029] Figure 3b A bottom view and a cross-sectional view of the lower shear gate provided in an embodiment of the present application.

[0030] Figure 4 Schematic diagram of the shearing process of the V-mouth shear gate provided in an embodiment of the present application.

[0031] Figure 5 A schematic diagram of the gate position before the shear gate seals the well provided in an embodiment of the present application.

[0032] Figure 6 A schematic diagram of the gate position after the shear gate provides a well seal in an embodiment of the present application.

[0033] Figure 7 A diagram showing the deformation process of the top seal of the shear gate under pressure provided in an embodiment of the present application.

[0034] Figure 8 A schematic diagram of the structure of the flow guide mechanism provided in an embodiment of the present application.

[0035] Fig. 9 A schematic diagram of the installation of the flow guide mechanism provided in an embodiment of the present application.

[0036] Fig.10a An upper side view of the upper shear gate provided in an embodiment of the present application.

[0037] Fig.10b A bottom view of the upper shear gate provided in an embodiment of the present application.

[0038] Fig.11aA top view of the lower shear gate provided in an embodiment of the present application.

[0039] Fig.11b A bottom view of the lower shear gate provided in an embodiment of the present application.

[0040] Fig.12 A schematic diagram of the coupling of the upper and lower shear gates provided in an embodiment of the present application.

[0041] Fig.13 The front view and left view of the casing structure provided in the embodiment of the present application.

[0042] Fig.14 This is a structural diagram of the transmission shaft provided in an embodiment of the present application.

[0043] Fig.15 This is a diagram of the piston structure provided in an embodiment of the present application.

[0044] Fig.16 A structural cross-sectional view of the gate feed mechanism provided in an embodiment of the present application.

[0045] Fig.17 The top sealing rubber body structure provided in the embodiment of the present application.

[0046] Fig.18 A V-shaped sealing ring provided in an embodiment of the present application.

[0047] Fig.19 A cross-sectional view of the sealing structure of the blowout preventer provided in an embodiment of the present application.

[0048] Fig. 20 An axonometric view of a control valve provided in an embodiment of the present application.

[0049] Fig.21 A cross-sectional view of the control valve structure provided in an embodiment of the present application.

[0050] Fig. 22 A side cross-sectional view of the flow guide mechanism provided in an embodiment of the present application.

[0051] Fig.23a A rear cross-sectional view of the position of the gate relative to the diversion port after well sealing provided in an embodiment of the present application.

[0052] Figure 23b An oblique side cross-sectional view of the position of the gate relative to the diversion port after well sealing provided in an embodiment of the present application.

[0053] Fig.24 A manual single-gate blowout preventer is provided in an embodiment of the present application.

[0054] In the figure:

[0055] 1. Cap nut; 2. Handle; 3. Transmission shaft; 4. Bearing housing; 5. Piston housing; 6. Housing; 7. Shear gate; 71. Upper shear gate; 711. First sealing groove; 712. First bending portion; 713. First shearing edge; 714. First guide groove; 715. First piston slot; 72. Lower shear gate; 721. Second sealing groove; 722. Second bending portion; 723. Second shearing edge; 724. Second guide groove; 72 5. Second piston slot; 8. Guide key; 9. Piston; 10. Screw; 11. Axial bearing; 12. Top sealing rubber body; 13. V-shaped sealing ring; 14. Rectangular sealing support body; 15. Trapezoidal sealing ring; 16. Rectangular sealing ring; 17. O-shaped sealing ring; 18. Bypass joint pipe; 19. Valve core; 20. Valve core shell; 21. Valve seat; 22. Bypass joint; 23. Guide pipe; 24. Control valve; 25. Guide mechanism; 26. Guide port. DETAILED DESCRIPTION

[0056] On the one hand, the present invention starts from the well control safety technology requirements of on-site well repair, breaks through the existing well control blowout preventer shear gate design based on statics theory, and considers the performance requirements of the shear gate under the dynamic service conditions of the blowout high-pressure fluid. On the other hand, from the perspective of reducing the cost of on-site well repair operations, the shear performance and sealing performance of the gate are integrated. The purpose of shearing the operating pipe string and sealing the wellhead in the case of sudden blowout during well repair is achieved, and the sudden blowout accident at the well repair site is controlled.

[0057] Considering the dynamic characteristics of abnormal blowout high-pressure fluid during well repair, in order to shear the sucker rod, seal the wellhead, and achieve well control safety in on-site well repair, the present invention integrates the functions of the traditional shear gate structure and the fully sealed gate structure into one gate body to form a shear blade part and a bending sealing part of the new gate structure. The overall structural design is as follows: Figure 2 The shear blade part solves the shearing problem, the bending seal part realizes the control of the water hammer impact and flow-induced vibration of the blowout high-pressure fluid, and the shear blade and the bending structure cooperate to realize the overall sealing of the gate.

[0058] The present invention is described in detail below in conjunction with the embodiments and drawings, but it should be understood that the embodiments and drawings are only used to exemplify the present invention and do not constitute any limitation on the protection scope of the present invention. All reasonable changes and combinations within the scope of the inventive concept of the present invention fall within the protection scope of the present invention.

[0059] The present invention will be further described below in conjunction with the accompanying drawings.

[0060] Example 1

[0061] like Figure 2, is a schematic diagram of a shear seal integrated well repair blowout preventer provided in this embodiment, hereinafter referred to as a blowout preventer, the blowout preventer includes a cross-shaped hollow shell 6, and the left and right side tubes of the shell 6 are respectively provided with shear gates 7 and gate feeding mechanisms for driving the shear gates 7, which are symmetrical and have the same structure, and are used to bend and squeeze the sucker rods in the upper and lower tubes passing through the shell 6.

[0062] The structure of the shear gate 7 is described as follows:

[0063] (1) Gate shear edge

[0064] The shearing capacity of the shear gate is related to the "V" opening angle and the blade surface inclination angle, which together determine the shearing force of the gate blade and the shearing capacity of the sucker rod. Figure 3a , Figure 3b , Fig.10a , Fig.10b , Fig.11a , Fig.11b and Fig.12 The shear gate 7 is cylindrical as a whole, and includes an upper shear gate 71 and a lower shear gate 72 that are coupled to shear and bend each other, and the upper shear gate 71 is concave to the right, as shown in FIG. Fig.10a The upper right portion is a first shearing edge 713, the middle portion is concave, and the lower portion is a first bending portion 712. The gate body is provided with a first sealing groove 711. Fig.10b , a first piston groove 715 is provided to the right, and a first guide groove 714 is provided on the bottom surface toward the shearing direction. The first guide groove 714 is used to limit the inward movement of the upper shear gate 71; Fig.11a , opposite to the upper shear gate 71, the lower shear gate 72 is concave to the left, the upper part is concave, the middle part is a second shearing blade 723, and the lower part is a second bending part 722. The gate body is provided with a second sealing groove 721, such as Fig.11b A second guide groove 724 is provided at the bottom toward the shearing direction, and a second piston groove 725 is provided toward the anti-shearing direction; wherein A is a "V"-shaped opening angle, and B is an inclination angle of the blade surface.

[0065] The model structure of the V-mouth gate blade acting on the cross section of the oil pipe shell is as follows Figure 4As shown. The two V-mouth gates have a total of four shear points on the middle cylindrical shell (the red circle indicates the contact point position). When the gates move relatively to squeeze the drill pipe, the four shear blade points also generate four symmetrical radial pressures on the drill pipe and play a certain clamping and fixing role. The blade surface inclination angle B is an important factor in measuring shear performance. Too large a blade surface inclination angle will produce excessive stress concentration, resulting in insufficient blade strength. A blade surface inclination angle that is too small cannot achieve the shear function well. Through simulation analysis, when the structural parameters of the shear gate are: "V"-shaped opening angle A is 165° and the blade surface inclination angle B is 120°, the blade strength is higher.

[0066] During the shearing process, the upper and lower shear gates work together, and the "V"-shaped opening angle A and the blade surface inclination angle B of the upper and lower shear gates are the same, but the upper and lower shear gates 7 have concave and convex structures corresponding to each other.

[0067] (2) Bending sealing part

[0068] The BOP well sealing process can be divided into two stages: shear well sealing process and well sealing completion process. The structural section diagram is as follows: Figure 5 , Figure 6 .in Figure 6 In the figure, the yellow rectangular area is the shear deformation area, and the red rectangular area is the extrusion deformation area. First, during the shear sealing process, the gate moves rapidly, and the sucker rod is often sheared within a few seconds. At this time, the high-pressure fluid in the sucker rod will produce water hammer impact and flow-induced vibration on the shear blade. The water hammer impact effect will hit the blade part of the shear gate, causing the gate blade part to vibrate, affecting the shear process of the gate and even causing shear failure. At the same time, the fluid will also produce flow-induced vibration in the gap position where the two gate blades overlap after shearing, resulting in a shortened service life of the shear blade. Secondly, after sealing the well, the wellhead is completely closed to ensure the safety of the well repair operation site.

[0069] In accordance with the purpose of the present application, this embodiment proposes a knife edge portion and a bending portion for the structure of the shear ram 7, which are used for shearing feeding and sealing and controlling flow, respectively. The shear ram 7 completes the action of shearing the sucker rod and sealing the wellhead during well repair. Then, based on the structure of the shear ram 7, a blowout preventer housing 6, a ram feeding mechanism, and a blowout preventer sealing and flow guiding mechanism 25 are provided. This solves the technical problem in the process of sealing the well with a blowout preventer during an emergency of abnormal blowout.

[0070] During the gate shearing and well sealing process, the first bending portion 712 and the second bending portion 722 are bent against each other to form a relative bending portion, which bends and squeezes the sucker rod, thereby initially controlling the high-pressure fluid in the sucker pipe and achieving the purpose of controlling water hammer impact and flow-induced vibration, thereby alleviating the impact and vibration of the fluid in the well on the upper shearing blade, and ensuring that the gate blade successfully shears the working pipe.

[0071] 2. Diversion mechanism

[0072] Because the feeding power structure adopts manual thread feeding, this embodiment proposes a flow guiding structure to solve the problem of difficulty in opening the well due to uneven pressure. After the well is sealed, the gate body will be self-locked due to the pressure difference in the vertical path, and this embodiment adopts manual thread transmission, which will make it more difficult to open the well. At this time, the flow guiding mechanism 25 is needed to conduct the pressure in the vertical path to reduce the static friction force received by the top seal of the gate body. The flow guiding mechanism 25 is installed on the external side of the blowout preventer shell and is connected by a threaded connection. Its structural diagram is shown as follows Figure 8 , the location diagram is as follows Fig. 9 The flow guide mechanism controls the fluid flow and pressure of the outlet and inlet through the control valve to control the pressure difference between the upper and lower surfaces of the gate in the vertical path, so that the gate top sealing rubber 12 will not produce a large static friction force, allowing the gate to move and solve the problem of difficulty in well opening on site.

[0073] Structural description of the shear gate: The designed shear gate 7 can seal the oil pipe during or after shearing, that is, realize the integrated design of shear sealing of the blowout preventer. The gate shear blade is at the top, and the bending part is at the bottom. A sealing groove is designed in the upper part, a guide groove is provided in the lower part, and a piston slot is provided at the tail. The top sealing rubber body 12 and the shell 6 are placed in the sealing groove to form a seal; the guide groove and the guide key 8 act to limit the rotational freedom of the gate, thereby ensuring the feeding of the gate; the piston slot and the piston are assembled to ensure the consistency of the transmission. The shearing openings and the bending parts of the upper and lower shear gates 7 are in different positions because they have to cooperate with each other, and the rest of the structures are consistent.

[0074] The structure of the shear gate in this embodiment is as follows Fig.10a , Fig.10b ,as well as Fig.11a , Fig.11b The upper and lower shear gates are collectively referred to as shear gate assemblies, and the coupling is as shown in Fig.12 shown.

[0075] In the prior art, when a blowout occurs, it is necessary to quickly control the high-pressure fluid ejected from the well. Therefore, the gate is required to quickly shear the sucker rod, which often results in the high-pressure fluid in the sucker rod generating water hammer impact and flow-induced vibration at the gate blade, causing the well to fail to shut in. In this embodiment, the bending structure exerts a squeezing effect on the sucker rod after the gate is combined, which can not only alleviate the water hammer impact and flow-induced vibration of the high-pressure fluid, but also seal the space in the pipe string to achieve the purpose of shutting in the well.

[0076] Shell structure description:

[0077] like Fig.13 As shown, the left figure is a front view and the right figure is a left view. The general structure of the shell 6 is a cross-shaped hollow. The upper and lower parts of the shell 6 are concentric vertical diameters, and the outer edge thereof has oil pipe threads on the outside to facilitate connection with other mechanisms. The structure on the left and right of the shell 6 is a concentric horizontal diameter, and the inner edge of the outer edge has threads to facilitate the installation of the piston housing 5. There is a groove for installing the guide key 8 near the vertical diameter, and the horizontal diameter is used to place the shear gate and its transmission device. There is a threaded hole on the front plane of the shell 6 to install the guide mechanism 25. The upper and lower parts of the shell 6 are connected by oil pipe threads and sleeves.

[0078] The gate feeding mechanism structure is described as follows:

[0079] The push of the gate feed mechanism can realize the shear gate's shearing and bending functions on the oil pipe. Fig.16 The feeding mechanism adopts the method of manually screwing the gate plate, which is to drive the transmission shaft 3 by rotating the handle 2, and then the piston converts the rotational motion into a lateral feeding motion, so that the piston 9 pushes the gate plate to move toward the center of the wellhead to achieve shearing and bending of the oil pipe.

[0080] like Fig.16 The gate feed mechanism is composed of a handle 2, a transmission shaft 3, a piston 9, two sets of axial bearings 11 and a shear gate 7. The handle 2 is fixed to the input end of the transmission shaft 3 through a cap nut 1, and the output end of the transmission shaft 3 and the piston 9 are connected through a trapezoidal thread, such as Fig.14 and Fig.15 The piston housing 5 and the housing 6 are fixed by threaded connection, and the bearing housing 4 is fixed to the piston housing 5 by screws 10. At this time, the housing 6, the piston housing 5 and the bearing housing 4 are fixed as a whole. The bearings 11 on the left and right sides of the shoulder on the transmission shaft 3 are in contact with the bearing housing 4 and the piston housing 5 respectively, fixing the transmission shaft 3 axially. The transmission shaft 3 can only achieve rotational movement. The piston 9 and the shear gate 7 are connected together by a slot, and the shear gate 7 is connected by the first guide groove 714, the second guide groove 724 and the guide key 8 to achieve axial feeding.

[0081] The drive is driven by rotating the handle 2, which drives the transmission shaft 3 to rotate and input power to the piston 9. Because the piston 9 and the shear gate 7 are assembled through mutually coupled slots, the power is converted into axial feed through the keyway, pushing the shear gate 7 to move toward the center of the wellhead.

[0082] Description of the gate rubber seal and transmission rubber seal structure of the blowout preventer:

[0083] like Fig.19 The sealing measures of the gate are divided into gate rubber seal and transmission rubber seal. The main purpose of the gate rubber seal is to control the sealing of the high-pressure fluid in the well to the well, and work with the shear gate 7 to achieve the integration of shearing and sealing. The purpose of the transmission rubber seal is to prevent impurities in the wellhead fluid from entering the threaded area, causing problems such as thread transmission stagnation and jamming, and to ensure the smooth transmission.

[0084] The housing rubber seal is achieved by the top sealing rubber body 12. Fig.17 , the top sealing rubber body 12 is arranged on the top of the upper shear gate 71 and the lower shear gate 72. The sealing principle of the top sealing rubber body 12: During the well sealing process, the piston 9 pushes the gate assembly 7 to move toward the wellhead under the action of the transmission shaft 3, so the bottom hole pressure is gradually applied to the lower part of the gate, but the top sealing rubber body 12 forms an interference fit with the blowout preventer housing. At this time, the rubber is in an extruded state under the pressure in the well, and the static friction force increases, so that the gate is self-locked after the shearing is completed. In this way, the bent part of the gate is continuously squeezed against the sucker rod to achieve well sealing after the shearing is completed, and the bottom hole pressure is controlled in time.

[0085] At present, the top sealing rubber body 12 is commonly used as a nitrile rubber body, which has excellent mechanical properties while maintaining oil resistance. When a well kick or blowout occurs, the pressure of the high-pressure fluid in the well will cause the sealing nitrile rubber body on the gate base to be subjected to radial and axial forces (sealing principle as shown in the figure). Figure 7 , Figure 7 .a shows that when there is no external pressure, the rubber body has no obvious deformation. Figure 7 .b shows that under radial pressure, the rubber body undergoes radial compression. Figure 7 .c shows that when subjected to radial and axial pressures at the same time, the deformation of the rubber body has a larger contact area with the upper surface of the shell), so that the nitrile rubber body is in close contact with the shell 6 of the blowout preventer, generating a friction force greater than the pressure in the well, so that the shear gate 7 will not retreat, and the bending structure will maintain the squeezing effect on the sucker rod, thereby achieving the effect of sealing the well.

[0086] After the well is sealed, the gate plate bending part and the top sealing rubber body 12 cooperate to complete the sealing of the wellhead. The bending parts 712 and 722 first completely squeeze and deform the sucker rod, so that the internal circulation space of the sucker rod is completely closed, and then a pressure difference will be generated on the upper and lower surfaces of the gate plate in the vertical path, and the friction force generated by the deformation of the gate plate's top sealing rubber body 12 will cause the gate plate body to form a self-locking, so that the bending part continues to squeeze the sucker rod, thereby realizing the sealing of the well and achieving the purpose of sealing the well.

[0087] The transmission rubber seal is mainly composed of a V-shaped sealing ring 13, a ladder-shaped sealing ring 15 and a rectangular sealing ring 16. Fig.18 , is a V-shaped seal ring 13. The sealing process of the V-shaped seal ring 13 is as follows: when the fluid in the well enters the chamber composed of the piston housing 5, the shear gate 7 and the piston 9, the high-pressure fluid will squeeze the V-shaped mouth of the V-shaped seal ring 13, so that an interference fit is formed between the V-shaped seal ring 13 and the piston 9, preventing the fluid from entering the threaded area of ​​the transmission shaft 3 behind, and playing a certain supporting role for the piston 9. The trapezoidal seal ring 15 is assembled at the connection between the transmission shaft 3 and the bearing housing 4, and the rectangular seal ring 16 is assembled between the bearing housing 4 and the piston housing 5. Its function is to prevent impurities in the well fluid from entering the chamber where the transmission shaft is located.

[0088] The functions of the other unmarked sealing rings are the same as those of the O-ring 17, which is to prevent other impurities in the well site environment from entering the blowout preventer structure.

[0089] Well repair gate blowout preventer flow guide mechanism 25 structure description:

[0090] The structure of the flow guiding mechanism 25 is as follows: Fig. 22 The flow guiding mechanism 25 has a control valve 24 below and a bypass joint 22 surrounded by a valve seat 21 above. The control valve 24 and the bypass joint 22 are connected through a flow guiding pipe 23 , and the entire flow guiding mechanism 25 is controlled by the control valve 24 .

[0091] like Figures 20-21 The valve core 19 and valve core housing 20 inside the control valve 24 are connected by a pin key and then connected to the bypass joint 18 by threading. The valve core housing 20 of the control valve 24 controls the closing and opening of the valve core 19 by tightening and loosening the threads with the bypass joint through pipe 18. At the same time, the control valve 24 and the bypass joint 22 are connected to the housing 6 and connected by the guide pipe 23, realizing the communication between the upper and lower chambers in the housing 6. The bypass joint 22 and the control valve 24 are connected toward the inside of the housing 6 to form a guide port 26, as shown in FIG. Fig.23a and Figure 23b .

[0092] The joint port of the flow guide mechanism 25 needs to enter the interior of the housing 6 and contact the high-pressure fluid inside the housing 6. The length of the flow guide pipe 23 ensures that the inlet and outlet positions of the two interfaces are not on the track of the gate feeding, which does not affect the normal feeding of the gate body. In addition, the upper and lower shear gates of this embodiment form an integral structure in shear coupling, and the overall structure formed by the shear gate 7 in shear coupling is similar to a rotating body, leaving enough space for the flow guide port 26 to guide the high-pressure fluid, such as Fig.23a and Figure 23b .

[0093] In this embodiment:

[0094] 1. Structure of shear gate: Based on the existing shear gate structure, the bending groove structure design is introduced to bend the gate before shearing the sucker rod, which preliminarily controls the blowout of high-pressure fluid in the pipe string, alleviates the water hammer impact and flow-induced vibration of the high-pressure fluid, ensures that the gate can shear smoothly, and after the shear gate is closed, the bending structure and the top seal are used to seal the well by squeezing the sucker rod.

[0095] 2. Gate feed mechanism: The fixing method of the gate feed mechanism adopts a combination of screws and threads, which reduces the processing difficulty but enhances the connection strength.

[0096] 3. Flow guide mechanism: Using a control valve can balance the pressure in the upper and lower cavities inside the shell.

[0097] Example 2

[0098] In this embodiment, the blowout preventer is driven by hydraulic control or electric drive instead of manual drive. Fig.24 Manual drive is manually driven by handle 2, while electric drive is to put the control terminal in the control room away from the wellhead blowout preventer, and the remote control motor drives the piston and gate to move forward, thereby achieving shearing and sealing the well. This not only protects the safety of well site workers, but also realizes intelligent control. The hydraulic control drive requires the oil circuit inside the shell to be modified so that it has two oil circuits for oil inlet and oil outlet, and the piston must be changed to hydraulic drive. The structure of the internal transmission shaft and piston can also be further streamlined to make the structure simpler and easier to disassemble and install. The diversion mechanism and the shell are further merged to reduce the possibility of problems with the mechanism. The shear gate can be replaced with a fully enclosed gate or a pipe gate to achieve the sharing of multiple gates and avoid waste of resources.

[0099] The above embodiments are only preferred implementations of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A well repair blowout preventer with integrated shear seal, comprising a housing (6), a shear ram (7) and a ram feed mechanism for driving the shear ram (7), characterized in that: The shell (6) is cross-shaped and hollow, and sucker rods are arranged in the upper and lower side diameters of the cross, and a pair of coupled shear gates (7) are symmetrically arranged in the left and right side diameters, respectively. The shear gates (7) include an upper shear gate (71) and a lower shear gate (72) that are coupled to shear and bend each other. The upper shear gate (71) and the lower shear gate (72) are driven by the gate feeding mechanism to shear and bend the sucker rod inward in a V-shape on the left and right sides, thereby completely sealing the well and controlling the flow during the well repair.

2. The well repair blowout preventer with integrated shear seal according to claim 1, characterized in that: The upper shear gate (71) and the lower shear gate (72) are both cylindrical; the upper shear gate (71) is provided with a first shearing blade (713) facing upward in the shearing direction, is concave in the middle, and is provided with a first bending portion (712) at the bottom; a first sealing groove (711) is provided inward at the top of the gate body, a first guide groove (714) is provided in the shearing direction at the bottom, and a first piston clamping groove (715) is provided towards the outward end; the lower shear gate (72) is concave in the shearing direction, is provided with a second shearing blade (723) in the middle, and is provided with a second bending portion (722) at the bottom; a second sealing groove (721) is provided inward at the top of the gate body, a second guide groove (724) is provided in the shearing direction at the bottom, and a second piston clamping groove (725) is provided towards the outward end.

3. The well repair blowout preventer with integrated shear seal according to claim 2, characterized in that: The first shearing edge (713) and the second shearing edge (723) both form a V-shaped opening angle when viewed from above, and the angle of the V-shaped opening angle is 165°; the inclination angle of the blade of the first shearing edge (713) and the second shearing edge (723) is 130°, and the concave and convex sides correspond to each other.

4. The well repair blowout preventer with integrated shear seal according to claim 2, characterized in that: The single gate feeding mechanism comprises a piston (9) coupled to a first piston slot (715) of the upper shear gate (71) or a second piston slot (725) of the lower shear gate (72); the piston (9) is connected to a transmission shaft (3) outwardly; an axial bearing (11) is axially arranged on the transmission shaft (3); the outer end of the transmission shaft (3) is driven manually or electrically to drive the piston (3) to drive the upper shear gate (71) or the lower shear gate (72) to perform inward shearing movement.

5. The well repair blowout preventer with integrated shear seal according to claim 4, characterized in that: The upper and lower shear gates are provided with sealing assemblies for top sealing and transmission sealing, and the gate feed mechanism is provided with sealing assemblies, the sealing assemblies include a bending seal and a transmission seal, the bending seal coupling is arranged in the first sealing groove (711) and the second sealing groove (721); the transmission seal includes a V-shaped sealing ring (13) arranged between the piston (9) and the piston housing (5), a trapezoidal sealing ring (15) arranged at the connection between the bearing housing (4) of the axial bearing (11), and a rectangular sealing ring (16) arranged between the bearing housing (4) and the piston housing (5).

6. The well repair blowout preventer with integrated shear seal according to claim 5, characterized in that: The material of the bending seal is selected from nitrile rubber.

7. The well repair blowout preventer with integrated shear seal according to claim 1, characterized in that: A vertically arranged flow guiding mechanism (25) is provided on one side of the cross of the shell (6), the flow guiding mechanism (25) comprising a control valve (24) on one side and a bypass joint (22) surrounded by a valve seat (21) on the other side, the control valve (24) and the bypass joint (22) being connected via a flow guiding pipe (23), the bypass joint (22) and the control valve (24) being connected toward the inside of the shell (6) to form a flow guiding port (26).

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