Blowout preventer, rubber core sealing adjustment method

Abstract

The application provides a blowout preventer and a rubber core sealing adjustment method, and belongs to the technical field of drilling equipment; the blowout preventer comprises an upper shell and a lower shell connected with the upper shell; the application further comprises a self-aligning assembly which is installed between the upper shell and the lower shell and is positioned and fixed through the upper shell and the lower shell; the self-aligning assembly comprises a first shell, a rubber core, an upper aligning unit and a lower aligning unit; the first shell is fixedly arranged between the upper shell and the lower shell; the rubber core is arranged in the first shell and is in contact with the upper aligning unit and the lower aligning unit arranged in the first shell; and the upper aligning unit is used for adjusting the position between the upper part of the rubber core and the drill pipe. The application can effectively solve the technical problem of sealing failure caused by the sealing deviation between the rotating blowout preventer rubber core and the drill pipe due to the high-frequency vibration of the drill string caused by the non-homogeneity of the formation lithology in the dynamic drilling process of the drill string.

Description

TECHNICAL FIELD

[0001] The application relates to the technical field of drilling equipment, and in particular to a blowout preventer and a rubber core sealing adjustment method. BACKGROUND

[0002] In the oil and gas drilling engineering, the well control system is the core defense line to ensure the safety of the operation. The rotary blowout preventer, as the key equipment of the system, plays an irreplaceable role in underbalanced drilling and managed pressure drilling technology. Its core function is to realize effective dynamic sealing of the annulus of the rotary drill string or full sealing of the wellhead in emergency conditions through the controllable radial deformation of the high-performance elastomer rubber core. This mechanism ensures that the wellbore static liquid column pressure can be accurately controlled at a critical condition slightly lower than the formation pore pressure, enabling safe implementation of pressure drilling and effectively preventing catastrophic accidents such as well kick or blowout.

[0003] During dynamic drilling, due to the non-uniformity of the formation lithology, i.e., the differences in rock hardness and properties at different positions of the formation, the drill string will produce high-frequency vibration when rotating and moving up and down. This high-frequency vibration causes the center of the contact sealing area between the drill string and the rubber core of the rotary blowout preventer to deviate, greatly affecting the sealing effect. Moreover, the eccentric contact between the rubber core sealing surface and the drill pipe causes the rubber core to bear high-intensity non-uniform loads for a long time, resulting in a decrease in its fatigue life.

[0004] According to the failure statistics of the American Petroleum Institute (API), 60% of rubber core failures are directly attributed to eccentric wear, which greatly shortens the actual service life of the rubber core compared to the theoretical value, with a reduction of 30-50%. This problem not only brings high spare part costs to enterprises, but also causes frequent replacement of the rubber core, which leads to unplanned downtime of drilling, seriously affecting the continuity of drilling operations and causing a significant increase in drilling costs.

[0005] The invention patent with the publication number CN118958912A discloses an annular rubber core and a blowout preventer, and relates to the field of oil drilling technology. The annular rubber core includes a rubber ring and a steel ring arranged on the bottom surface thereof, and the two are integrated by vulcanization adhesion, and the adhesion surfaces of the two are of consistent size. The blowout preventer includes: a blowout preventer body including a top cover, an outer shell, and a plurality of pistons arranged inside the blowout preventer body, a through slot passing through the blowout preventer body from top to bottom is arranged at the center of the blowout preventer body, the through slot is used for inserting a drill pipe, and the top cover covers the outer shell; a first wear plate is arranged at the bottom of the top cover; a plurality of rubber cores with the same thickness and different outer diameters are sequentially sleeved from inside to outside, the annular rubber core at the outermost circle is tightly attached to the inner wall of the outer shell, the rubber ring at the top surface of the annular rubber core is tightly attached to the first wear plate, and the plurality of pistons are respectively connected to the steel rings of the corresponding annular rubber cores and used for moving the steel rings upward to make the rubber ring at the innermost circle tightly attached to the drill pipe. When one annular rubber core is worn and affects the sealing effect, it is not necessary to replace all annular rubber cores.

[0006] The invention patent with publication number CN113250640B discloses a ring-shaped blowout preventer, a rotating sleeve is movably installed at the bottom of the shell, a rubber core is movably installed at the top of the support cylinder inside the shell, a piston is movably installed at the bottom of the support cylinder and the rubber core inside the shell, an oil pressure adjusting groove is formed in the middle of the inner wall of the shell, an oil extraction plug is movably sleeved at the bottom of the oil pressure adjusting groove, a hydraulic ring groove is formed at the bottom position of the inner wall of the shell, a rubber plug is movably sleeved at the inner ring of the hydraulic ring groove, a guide wheel is movably sleeved inside the contraction groove, cams are fixedly installed on the two sides of the guide wheel, hydraulic adjusting cavities are formed at the bottom position of the hydraulic adjusting groove on the two sides of the inner wall of the shell, a top rod is movably sleeved inside the hydraulic adjusting cavity, hydraulic cavities are symmetrically formed on the front and back surfaces of the inner wall of the shell, and the cooperation of the shell structure, the guide wheel and the rubber plug inside the shell ensures that the rubber core in the blowout preventer is less damaged and improves the working efficiency when the drill pipe is tripped in.

[0007] The invention patent with publication number CN114635663B discloses a closed-loop control method for a rotary blowout preventer, which is realized by a rotary blowout preventer and a hydraulic control device. The rotary blowout preventer comprises a shell assembly, a rotating assembly, and a drilling fluid recovery and drainage device. The shell assembly comprises a shell, a first pressure sensor, and at least two sets of hydraulic cylinder locking components. The shell is fixedly and sealingly connected with an annular blowout preventer at a wellhead. The first pressure sensor can detect the pressure inside the shell. The at least two sets of hydraulic cylinder locking components lock the rotating assembly and the shell assembly. The drilling fluid recovery and drainage device can pump the leaked drilling fluid into a drilling fluid circulating tank. The rotating assembly is arranged in the shell assembly and can rotate along the axis of the shell assembly. The rotating assembly can close the internal passage of the shell assembly. The hydraulic control device is connected with the rotary blowout preventer to control the rotary blowout preventer.

[0008] In drilling operations, the non-homogeneity of formation lithology induces severe multi-modal vibration of the drill string, which causes dynamic center deviation when the drill string passes through the rotary blowout preventer, resulting in local high-stress eccentric contact between the outer wall of the drill string and the sealing surface of the rubber core. This contact mode under non-design conditions significantly accelerates the eccentric wear failure of the rubber core, not only greatly shortening its service life, but also weakening the key sealing barrier function of the rotary blowout preventer in underbalanced drilling, significantly increasing the well control risk. SUMMARY

[0009] The purpose of the present application is to provide a blowout preventer and a rubber core sealing adjustment method, which can effectively solve the technical problem of sealing failure caused by the eccentricity of the rubber core and the drill pipe due to the high-frequency vibration of the drill string in the dynamic drilling process.

[0010] To solve the above technical problems, the technical solution adopted by the present application is:

[0011] The blowout preventer comprises an upper shell and a lower shell connected with the upper shell, and further comprises a self-aligning assembly installed between the upper shell and the lower shell and positioned and fixed by the upper shell and the lower shell.

[0012] The self-aligning assembly comprises a first shell, a rubber core, an upper aligning unit and a lower aligning unit, the first shell is fixedly arranged between the upper shell and the lower shell, the rubber core is arranged in the first shell and in contact with the upper aligning unit and the lower aligning unit installed in the first shell, the upper aligning unit is used for adjusting the position between the upper part of the rubber core and the drill pipe, and the lower aligning unit is used for adjusting the position between the lower part of the rubber core and the drill pipe.

[0013] The upper aligning unit comprises a displacement sensor and a plurality of aligning hydraulic cylinders, the aligning hydraulic cylinders are equidistantly arranged in the first shell and in contact with the side surface of the rubber core, and the displacement sensor is installed on the inner wall of the first shell.

[0014] The lower aligning unit comprises an aligning frame, an aligning ring, an aligning ball cage and aligning beads, the inner wall surface of the aligning frame is provided with a first circular arc track, the outer wall surface of the aligning ring is provided with a second circular arc track, the second circular arc track cooperates with the first circular arc track of the inner wall surface of the aligning frame, the aligning beads are installed on the aligning ball cage and located between the first circular arc track and the second circular arc track, the aligning frame is installed in the first shell, and the aligning ring is used for contacting the rubber core.

[0015] The inner wall surface of the aligning ring is conical, and the conical angle is consistent with the conical angle of the rubber core.

[0016] Further, the first shell comprises an aligning base and an aligning assembly cover, the aligning base and the aligning assembly cover are fixedly connected, the aligning hydraulic cylinders are arranged on the aligning base, and the lower aligning unit is installed on the aligning base.

[0017] The upper shell and the lower shell are detachably connected and provided with a sealing ring.

[0018] The aligning base and the aligning assembly cover are connected through threads.

[0019] The upper shell and the lower shell are provided with hydraulic channels connected with the aligning hydraulic cylinders.

[0020] The upper shell and the lower shell are provided with communication channels.

[0021] Further, the aligning base and the aligning frame are connected through splines.

[0022] Further, the upper shell is connected with a square compensating core through a thrust bearing and a radial bearing set, the square compensating core is connected with the drill pipe, and the drill pipe passes through the rubber core and is in close contact with the rubber core.

[0023] In addition, the application also discloses a sealing adjusting method of the rubber core, and the specific adjusting method is as follows:

[0024] S101: Real-time monitoring of the eccentricity of the rubber core, the contact position of the rubber core and the drill pipe is dynamically monitored through the displacement sensors uniformly arranged on the centering base, and the eccentricity data of the rubber core sealing surface is obtained;

[0025] S102: Multi-directional collaborative adjustment of the position of the rubber core, the feedback signals of the displacement sensors are used to independently control the extension and retraction of the piston rods of the uniformly arranged centering hydraulic cylinders; the piston rods of the centering hydraulic cylinders directly abut against the side surface of the rubber core and apply radial thrust, and the eccentricity of the rubber core is compensated through the collaborative extension and retraction of the centering hydraulic cylinders, so that the rubber core sealing surface uniformly clamps the drill pipe;

[0026] S103: Dynamic adaptation of the sealing angle, the bottom of the rubber core is subjected to adaptive angle change through the lower centering unit; when the centering hydraulic cylinders push the top of the rubber core to displace, the centering beads move along the first and second circular arc tracks and drive the centering ring to synchronously adjust the angle.

[0027] Compared with the prior art, the application has the following beneficial effects:

[0028] The application simplifies the original complex mechanical structure, reduces the difficulty of processing, installation and maintenance, and adopts the split design of the upper shell and the lower shell, so that the rubber core is convenient to maintain and disassemble, and the time cost of maintenance is reduced.

[0029] The self-centering assembly adopts modular design, so that the stability of the device is improved and the adaptability is enhanced.

[0030] The service life of the rubber core is enhanced, the sealing position of the rubber core is monitored in real time through the laser displacement sensor, the sealing angle is timely regulated through the centering hydraulic cylinder, the stress state of the rubber core of the rotary blowout preventer is effectively improved, the service life of the rubber core is effectively prolonged, the drilling time caused by replacement of the rubber core is shortened, and the drilling cost is reduced. BRIEF DESCRIPTION OF DRAWINGS

[0031] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiments. It should be understood that the following drawings only show some embodiments of the application, and therefore should not be regarded as a limitation to the scope, and other related drawings can be obtained by those skilled in the art without creative labor.

[0032] Figure 1 The overall structure schematic diagram of the present application.

[0033] Figure 2 The contact schematic diagram of the present application glue core and drill pipe.

[0034] Figure 3 The assembly schematic diagram of the present application adjusting base and lower adjusting unit.

[0035] Figure 4 The overall structure schematic diagram of the present application self-adjusting assembly.

[0036] Figure 5 The cooperation relationship schematic diagram of the present application adjusting base and adjusting frame.

[0037] Figure 6 The overall structure schematic diagram of the present application adjusting ring.

[0038] Figure 7 The overall structure schematic diagram of the present application adjusting frame.

[0039] Figure 8 The overall structure schematic diagram of the present application adjusting ball cage.

[0040] Reference signs:

[0041] 1-ways to fill the heart, 2-bearing cover, 3-radial bearing group, 4-thrust bearing, 5-upper shell, 6-connection bolt, 7-self-adjusting assembly, 701-adjusting assembly cover, 702-gel core, 703-adjusting hydraulic cylinder, 704-adjusting base, 705-adjusting frame, 706-adjusting bead, 707-adjusting ball cage, 708-adjusting ring, 8-sealing ring, 9-lower shell, 10-displacement sensor, 11-pressure sensor, 12-upper adjusting unit, 13-lower adjusting unit, 14-first shell, 15-hydraulic channel, 16-communication channel, 17-drill pipe, 18-first circular arc track, 19-second circular arc track. DETAILED DESCRIPTION

[0042] Hereinafter, only certain exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the embodiments of the present application. Therefore, the drawings and the description are considered to be exemplary in nature rather than limiting.

[0043] In the description of the embodiments of the present invention, it should be understood that the terms "length", "vertical", "horizontal", "top", "bottom", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the drawings. They are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0044] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of embodiments of the present invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0045] In this embodiment of the invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," "linking," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection, an electrical connection, or a communication connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this embodiment of the invention according to the specific circumstances.

[0046] In embodiments of the present invention, unless otherwise explicitly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0047] The following disclosure provides many different implementations or examples for carrying out different structures of the embodiments of the present invention. To simplify the disclosure of the embodiments of the present invention, specific examples of components and arrangements are described below. Of course, these are merely examples and are not intended to limit the embodiments of the present invention. Furthermore, reference numerals and / or reference letters may be repeated in different examples of the embodiments of the present invention; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various implementations and / or arrangements discussed.

[0048] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings.

[0049] Referring to Figures 1-8 The embodiment discloses a blowout preventer, comprising an upper shell 5 and a lower shell 9 connected with the upper shell 5, and further comprising a self-aligning assembly 7 installed between the upper shell 5 and the lower shell 9 and positioned and fixed by the upper shell 5 and the lower shell 9; the upper shell 5 and the lower shell 9 are connected by connecting bolts 6.

[0050] The self-aligning assembly 7 comprises a first shell 14, a rubber core 702, an upper aligning unit 12 and a lower aligning unit 13, the first shell 14 is fixedly arranged between the upper shell 5 and the lower shell 9, the rubber core 702 is arranged in the first shell 14, and the rubber core 702 is in contact with the upper aligning unit 12 and the lower aligning unit 13 arranged in the first shell 14; the upper aligning unit 12 is used for adjusting the position between the upper part of the rubber core 702 and the drill pipe 17, and the lower aligning unit 13 is used for adjusting the position between the lower part of the rubber core 702 and the drill pipe 17.

[0051] The upper aligning unit 12 comprises a displacement sensor 10 and a plurality of aligning hydraulic cylinders 703, the aligning hydraulic cylinders 703 are equidistantly arranged in the first shell 14, and the movable ends of the aligning hydraulic cylinders 703 are in contact with the side surface of the rubber core 702; the displacement sensor 10 is arranged on the inner wall of the first shell 14,

[0052] The lower aligning unit 13 comprises an aligning frame 705, an aligning ring 708, an aligning ball cage 707 and aligning beads 706, the inner wall surface of the aligning frame 705 is provided with a first circular-arc-shaped track 18, the outer wall surface of the aligning ring 708 is provided with a second circular-arc-shaped track 19, the second circular-arc-shaped track 19 cooperates with the first circular-arc-shaped track 18 of the inner wall surface of the aligning frame 705, the aligning beads 706 are arranged on the aligning ball cage 707 and located between the first circular-arc-shaped track 18 and the second circular-arc-shaped track 19, the aligning frame 705 is arranged in the first shell 14, and the aligning ring 708 is used for contacting the rubber core 702.

[0053] The inner wall surface of the aligning ring 708 is conical, and the conical angle is consistent with the conical angle of the rubber core 702.

[0054] Further, the first shell 14 comprises an aligning base 704 and an aligning assembly cover 701, the aligning base 704 and the aligning assembly cover 701 are fixedly connected, the aligning hydraulic cylinders 703 are arranged on the aligning base 704, and the lower aligning unit 13 is arranged on the aligning base 704.

[0055] The upper shell 5 and the lower shell 9 are detachably connected and provided with a sealing ring 8.

[0056] Further, the aligning base 704 and the aligning assembly cover 701 are connected by threads.

[0057] Further, the upper shell 5 and the lower shell 9 are provided with hydraulic channels 15 connected with the aligning hydraulic cylinder 703.

[0058] Further, the upper shell 5 and the lower shell 9 are provided with communication channels 16.

[0059] Further, the aligning base 704 and the aligning frame 705 are connected through the spline.

[0060] Further, the upper shell 5 is connected with the square compensator 1 through the thrust bearing 4 and the radial bearing group 3, the square compensator 1 is connected with the drill pipe 17, the drill pipe 17 passes through the rubber core 702 and is in close contact with the rubber core 702, and the radial bearing group 3 is fixed by the bearing cover 2.

[0061] Further, the hydraulic channels 15 are connected with the pressure sensor 11.

[0062] The present application monitors the eccentricity of the rubber core 702 through the displacement sensor 10, adjusts the eccentric position of the rubber core 702 through the aligning hydraulic cylinder 703, and optimizes the sealing surface of the rubber core 702 in real time, thereby improving the service life of the rubber core 702 of the rotary blowout preventer, effectively prolonging the service life of the rubber core 702, monitoring the hydraulic pressure when the rubber core 702 is compressed and rebounded during the sealing process through the pressure sensor 11, judging the fatigue health of the rubber core 702, and replacing the rubber core 702 in time, which not only ensures the safety of drilling, but also shortens the drilling time caused by replacing the rubber core 702 and reduces the cost of drilling.

[0063] In order to facilitate further understanding of the present application by those skilled in the art, the present application is further described below.

[0064] A self-diagnosis modular rotary blowout preventer, the square compensator 1 is connected with the thrust bearing 4 and the radial bearing group 3 and the upper shell 5, the upper shell 5 and the lower shell 9 are fixedly connected through the connecting bolts 6, so that the upper shell 5 and the lower shell 9 can be disassembled, and the self-aligning assembly 7 can be quickly replaced.

[0065] The square compensator 1 is a steel part with an upper square and a lower circle, which is sleeved on the drill pipe 17 and is driven by a rotary table or a top drive to apply torque to the drill string during rotary drilling.

[0066] A sealing ring 8 is arranged between the upper shell 5 and the lower shell 9, and a shoulder is arranged in the upper shell 5 for limiting the installation of the self-aligning assembly 7.

[0067] Communication channels 16 are arranged in the upper shell 5 and the lower shell 9 to realize wiring of the displacement sensor 10; hydraulic channels 15 are arranged in the upper shell 5 and the lower shell 9.

[0068] The self-aligning assembly 7 is located between the upper shell 5 and the lower shell 9, is limited by the internal shoulder of the upper shell 5 and the internal shoulder of the lower shell 9, and is fixedly connected by bolts.

[0069] The self-aligning frame 705 is installed in the self-aligning base 704 by the positioning shoulder, is connected with the self-aligning ring 708 by the self-aligning beads 706 and the tracks (the first circular arc track 18 and the second circular arc track 19) in the self-aligning frame 705, and the self-aligning assembly cover 701 is connected with the self-aligning base 704 by screws.

[0070] The self-aligning beads 706 are located between the first circular arc track 18 and the second circular arc track 19, and enable the self-aligning ring 708 to be angularly deflected relative to the self-aligning frame 705.

[0071] The displacement sensor 10 is a laser displacement sensor 10, is installed on the self-aligning base 704 by threads, and is used for monitoring the rebound pressure of the rubber core 702 to judge the fatigue state.

[0072] In the working process, the square compensator 1 is connected with the drill pipe 17 by API threads, is driven to rotate and drill by the upper rotary table or the top drive. When the operation is carried out under pressure, the pressure in the wellbore is slightly less than the formation pressure, in order to ensure the safety of drilling, the radial thrust is applied to the self-aligning hydraulic cylinder 703 through the hydraulic flow channel on the side of the lower shell 9, the piston rod of the self-aligning hydraulic cylinder 703 is pushed outwards, the rubber core 702 is radially deformed to "hug" the drill pipe 17, the square compensator 1, the drill pipe 17 and the rotating blowout preventer rubber core 702 rotate together in the drilling process, and the upper shell 5, the lower shell 9, the self-aligning hydraulic cylinder 703, the self-aligning assembly cover 701 and the self-aligning base 704 remain stationary.

[0073] Six self-aligning hydraulic cylinders 703 are uniformly distributed on the upper part of the self-aligning assembly 7 in the circumferential direction, and the end of the piston rod of the self-aligning hydraulic cylinder 703 is in a circular arc structure and is in contact with the cylindrical end surface of the rubber core 702.

[0074] When the self-aligning assembly 7 works, the hydraulic oil enters the rodless cavity end surface of the self-aligning hydraulic cylinder 703 from the hydraulic channel 15 of the lower shell 9, and pushes the piston rod of the self-aligning hydraulic cylinder 703 to extend. The rodless cavity region of the self-aligning hydraulic cylinder 703 is provided with a pressurizing hole connected with the hydraulic channel 15 of the upper shell 5, the rod cavity region is provided with a pressure relief hole leading to the sealing area of the rubber core 702, and the end of the piston rod of the self-aligning hydraulic cylinder is in an arc structure and is in contact with the cylindrical surface of the drill pipe 17.

[0075] When the contact surface between the sealing end surface of the rubber core 702 and the drill pipe 17 is offset, the position of the rubber core 702 is adjusted by the six self-aligning hydraulic cylinders 703, so that the rubber core 702 is always in uniform contact with the cylindrical end surface of the drill pipe 17, thereby improving the stress state of the rubber core 702 in the process of drilling under pressure and prolonging the service life of the rubber core 702.

[0076] When pressure relief, the pressure of the hydraulic passage 15 is closed, the rubber core 702 resets under the action of the elastic force, the centralizing hydraulic cylinder 703 is pushed to move, the hydraulic oil is discharged, the pressure sensor 11 is installed outside the lower shell 9, the pressure of the hydraulic oil inlet and outlet is monitored, so that whether the rubber core 702 is fatigue failure is judged, the rubber core 702 is replaced in advance, and the well control accident is prevented.

[0077] Six laser displacement sensors 10 are uniformly distributed in the circumferential direction below the centralizing assembly of the centralizing hydraulic cylinder 703, the laser displacement sensor 10 is installed on the centralizing base 704 through threads, and the communication line and the power line are connected with the ground device through the communication passage 16 on the side of the lower shell 9.

[0078] During the working process, the sealing angle of the rubber core 702 is dynamically monitored through the laser displacement sensor 10, the signal is transmitted to the ground driller platform, the sealing of the rubber core 702 is adjusted in real time according to the position of the rubber core 702, and the centralizing hydraulic cylinder 703 is used.

[0079] A shoulder is arranged at the bottom of the centralizing base 704 for positioning and installation of the centralizing frame 705, an internal spline groove is arranged in the centralizing base 704, and an external spline is arranged on the outer circle of the centralizing frame 705 and matched with the internal spline groove. Six round holes are uniformly distributed on the centralizing cage 707, the centralizing beads 706 are installed in the round holes, the inner wall surface of the centralizing frame 705 is processed into a circular arc track, the outer wall surface of the centralizing ring 708 is arranged as a circular arc track matched with the track of the inner wall surface of the centralizing frame 705, so that the centralizing beads 706 run in the track, and the inner wall surface of the centralizing ring 708 is conical and has an angle consistent with the taper angle of the rubber core 702. During the working process, the piston rod of the centralizing hydraulic cylinder pushes the top position of the rubber core 702, and the bottom area of the centralizing beads 706 moves in the track between the centralizing frame 705 and the centralizing ring 708, so that the sealing angle of the rubber core 702 is adjusted.

[0080] The displacement sensor 10 signal is transmitted to the ground control system, and independent control instructions of each centralizing hydraulic cylinder 703 are generated after PID algorithm processing, and the extension and retraction amount of the piston rod is adjusted through the hydraulic passage 15.

[0081] The embodiment also discloses a sealing adjustment method of the rubber core 702, and the sealing adjustment method of the rubber core 702 comprises the following steps.

[0082] S101: Real-time monitoring of the eccentricity of the rubber core 702, the contact position of the rubber core 702 and the drill pipe 17 is dynamically monitored through the displacement sensor 10 uniformly distributed on the centralizing base 704, and the eccentricity data of the sealing surface of the rubber core 702 is obtained.

[0083] S102: Multidirectional cooperative adjustment of the position of the rubber core 702, independent control of the extension and retraction of the piston rod of the aligning hydraulic cylinder 703 uniformly arranged according to the feedback signal of the displacement sensor 10; the piston rod of the aligning hydraulic cylinder 703 directly abuts against the side surface of the rubber core 702, applies a radial thrust, and compensates for the eccentricity of the rubber core 702 through the cooperative extension and retraction of the aligning hydraulic cylinder 703, so that the rubber core 702 uniformly clamps the drill pipe 17 on the sealing surface;

[0084] S103: Dynamic adaptation of the sealing angle, the bottom of the rubber core 702 is subjected to adaptive angle change through the lower aligning unit 13; when the aligning hydraulic cylinder 703 pushes the top of the rubber core 702 to displace, the aligning bead 706 moves along the first circular arc track 18 and the second circular arc track 19, and drives the aligning ring 708 to synchronously adjust the angle.

[0085] In specific implementation, the bottom of the rubber core 702 is subjected to adaptive angle change through the first circular arc track 18 and the second circular arc track 19 follow-up mechanism:

[0086] The conical inner wall of the aligning ring 708 is in contact with the conical surface of the rubber core 702, and the angles are consistent;

[0087] The aligning bead 706 rolls between the first circular arc track 18 of the aligning frame 705 and the second circular arc track 19 of the aligning ring 708;

[0088] When the aligning hydraulic cylinder 703 pushes the top of the rubber core 702 to displace, the aligning bead 706 moves along the first circular arc track 18 and the second circular arc track 19, and drives the aligning ring 708 to synchronously adjust the angle.

[0089] In actual application, the outer wall of the aligning frame 705 is connected with the aligning base 704 through spline connection, and the aligning frame 705 and the aligning base 704 are connected and kept stable during operation. The first circular arc track 18 arranged on the inner wall of the aligning frame 705 adopts an arc surface track design, the number of the first circular arc track 18 of the aligning frame 705 is the same as the number of the second circular arc track 19 on the aligning ring 708, and both are six.

[0090] During installation, the aligning bead 706 is installed between the first circular arc track 18 and the second circular arc track 19, and the aligning bead 706 is in conjugate contact with the first circular arc track 18 and the second circular arc track 19 during the rotation of the blowout preventer aligning operation.

[0091] The first circular arc track 18 and the second circular arc track 19 are in the shape of an ellipse, and the eccentricity of the ellipse is determined by the maximum working angle of the universal joint. The greater the angle, the greater the eccentricity of the ellipse required. To ensure that the self-aligning assembly 7 has a certain bearing capacity during the alignment operation of the blowout preventer, the angle between the normal direction of the contact point of the aligning bead 706 and the first circular arc track 18 and the second circular arc track 19 and the axial direction is controlled to be 6-12°. The radius of curvature is greater than the radius of the aligning bead 706 to provide a certain gap to accommodate lubricating grease and allow slight misalignment.

[0092] In some preferred embodiments, S104 is further included: monitoring the change of oil pressure in the hydraulic channel 15 through the pressure sensor 11, comparing the rebound pressure of the rubber core 702 with the fatigue threshold, and determining the risk of elastic failure.

[0093] The pressure sensor 11 is used to monitor the change of oil pressure in the hydraulic channel 15 in real time:

[0094] When sealed: record the pressurizing pressure of the aligning hydraulic cylinder 703;

[0095] When depressurized: monitor the pressure of the rubber core 702 rebounding to push the hydraulic oil out of the aligning hydraulic cylinder 703;

[0096] Compare the pressure data with the fatigue threshold to determine the risk of elastic failure of the rubber core 702 and give a warning for replacement.

[0097] Although the preferred embodiments of the present application have been described, those skilled in the art can make further changes and modifications to these embodiments once they know the basic inventive concept. Therefore, the appended claims are intended to be interpreted as including all the preferred embodiments and all the changes and modifications falling within the scope of the present application.

[0098] The above description is only the preferred embodiment of the present application and is not intended to limit the present application. It should be pointed out that any modification, equivalent replacement and improvement made within the spirit and principle of the present application should be included in the protection scope of the present application.

Claims

1. A blowout preventer, comprising an upper housing and a lower housing connected to the upper housing, characterized in that: It also includes a self-aligning assembly, which is installed between the upper housing and the lower housing and is positioned and fixed by the upper housing and the lower housing; The self-aligning assembly includes a first housing, a rubber core, an upper self-aligning unit, and a lower self-aligning unit. The first housing is fixedly disposed between the upper and lower housings. The rubber core is disposed within the first housing and contacts the upper and lower self-aligning units installed within the first housing. The upper self-aligning unit is used to adjust the position between the upper part of the rubber core and the drill pipe, and the lower self-aligning unit is used to adjust the position between the lower part of the rubber core and the drill pipe. The upper self-aligning unit includes a displacement sensor and several self-aligning hydraulic cylinders. The several self-aligning hydraulic cylinders are equally spaced within the first housing, and the movable ends of the self-aligning hydraulic cylinders contact the side of the rubber core. The lower self-aligning unit includes a self-aligning frame, a self-aligning ring, a self-aligning ball cage, and a self-aligning bead. The inner wall of the self-aligning frame is provided with a first arc-shaped track, and the outer wall of the self-aligning ring is provided with a second arc-shaped track. The second arc-shaped track cooperates with the first arc-shaped track on the inner wall of the self-aligning frame. The self-aligning bead is installed on the self-aligning ball cage and located between the first and second arc-shaped tracks. The self-aligning frame is installed within the first housing, and the self-aligning ring is used to contact the rubber core.

2. A blowout preventer according to claim 1, characterized in that: The first housing includes a self-aligning base and a self-aligning assembly cover, which are fixedly connected. The self-aligning hydraulic cylinder is mounted on the self-aligning base, and the lower self-aligning unit is mounted on the self-aligning base.

3. A blowout preventer according to claim 1, characterized in that: The upper and lower housings are detachably connected and equipped with a sealing ring.

4. A blowout preventer according to claim 1, characterized in that: The upper and lower housings are provided with hydraulic channels that connect to the self-aligning hydraulic cylinder.

5. A blowout preventer according to claim 1, characterized in that: Communication channels are provided on the upper and lower housings.

6. A blowout preventer according to claim 1, characterized in that: The self-aligning base and the self-aligning frame are connected by a spline.

7. A blowout preventer according to any one of claims 1-6, characterized in that: The upper housing is connected to the square core via a thrust bearing and a radial bearing assembly. The square core is connected to the drill rod, and the drill rod passes through the rubber core and is in close contact with the rubber core.

8. A method for adjusting the seal of a rubber core, characterized in that: Including the use of a blowout preventer as described in claim 1, the specific adjustment method is as follows: S101: Real-time monitoring of rubber core eccentricity. The contact position between the rubber core and the drill rod is dynamically monitored by displacement sensors evenly distributed on the self-aligning base to obtain the eccentricity data of the rubber core sealing surface. S102: Multi-directional coordinated adjustment of the rubber core position. Based on the feedback signal from the displacement sensor, the piston rods of the evenly distributed self-aligning hydraulic cylinders are independently controlled to extend and retract. The piston rods of the self-aligning hydraulic cylinders directly abut against the side of the rubber core, applying radial thrust. The coordinated extension and retraction of the self-aligning hydraulic cylinders compensates for the eccentricity of the rubber core, so that the sealing surface of the rubber core evenly grips the drill rod. S103: Dynamically adapts to the sealing angle. The bottom of the rubber core adapts to the angle change through the lower self-aligning unit. When the self-aligning hydraulic cylinder pushes the top of the rubber core to move, the self-aligning ball moves along the first and second arc tracks, driving the self-aligning ring to adjust the angle synchronously.

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