A broken rod blowout preventer wellhead seal

Abstract

The present application belongs to the technical field of petroleum engineering, and particularly relates to a broken rod blowout preventer wellhead sealing device. The device comprises a functional part, the upper side of the functional part is fixedly connected with a bottom shell, a packing is arranged in the bottom shell, the upper part of the bottom shell is threadedly connected with a top shell, the upper side of the top shell is threadedly connected with a blowout preventer shell, the bottom shell and the top shell are jointly sealed and slidably connected with a pressure applying part for extruding the packing, a first spring is fixedly connected between the pressure applying part and the top shell, and a detection assembly and a plugging assembly are arranged in the blowout preventer shell. The present application utilizes the phenomenon that the packing is rapidly compressed due to the loss of internal support caused by the light rod breakage, judges whether the light rod is broken, judges whether the wellhead needs to be plugged, and thus makes the blowout preventer device not need to be directly in contact with the light rod, avoids the wear between the blowout preventer device and the light rod, reduces the frequency of inspection and maintenance, slows down the wear speed of the light rod, and reduces the maintenance cost and workload.

Description

Technical Field

[0001] This invention belongs to the field of petroleum engineering technology, and specifically relates to a wellhead sealing device for preventing blowouts due to rod breakage. Background Technology

[0002] In oil extraction, the pumping unit is a critical piece of equipment. Its core component, the polished rod, has its upper end connected to the suspension cable of the pumping unit and its lower end connected to the sucker rod. As the pumping unit operates, the polished rod reciprocates up and down, driving the sucker rod below and the pump at its end, lifting crude oil to the surface through piston-like motion. However, as the depth of the pump in the wellbore increases, the load on the polished rod also increases. This continuously increasing load can easily cause the polished rod to break or disengage. Once the polished rod breaks off, pressurized media (such as crude oil, natural gas, and water) at the bottom of the well will instantly gush out, severely damaging wellhead equipment and causing environmental pollution accidents.

[0003] Currently, to address the risk of well media ejection following polished rod breakage, blowout preventers (BOPs) are typically installed above the packing box at the wellhead. Spherical seal BOPs are a common type, working by using the accumulated spring force of a pre-tensioned spring to push a sealing sphere tightly against the polished rod surface. When the polished rod breaks off, the sealing sphere, now unsupported, moves rapidly under the spring force, thus sealing the wellhead. However, this method relies on whether the polished rod provides support for the sealing sphere as the criterion for polished rod breakage. This not only causes direct contact between the polished rod and the sealing sphere, leading to wear and accelerating polished rod wear, but also necessitates periodic replacement of the sealing sphere, increasing maintenance costs and workload. Summary of the Invention

[0004] This invention provides a wellhead sealing device for broken rod blowout preventers, overcoming the disadvantages of high maintenance costs and heavy workload of existing blowout preventers.

[0005] The technical solution adopted in this invention is: a blowout preventer wellhead sealing device for broken rods, comprising a functional component, a bottom shell fixedly connected to the upper side of the functional component, a packing gland disposed inside the bottom shell, a top shell threadedly connected to the upper part of the bottom shell, a blowout preventer shell threadedly connected to the upper side of the top shell, a pressure-applying component for compressing the packing gland being slidably connected together by the bottom shell and the top shell, a first spring fixedly connected between the pressure-applying component and the top shell, the upper side of the pressure-applying component passing through the top shell and threadedly connected to a threaded ring, and a detection device disposed inside the blowout preventer shell. The components include a detection cylinder, a detection disc, a second spring, a connector, and an elastic strip. The detection cylinder is disposed inside the blowout preventer and is filled with damping oil. The detection disc is slidably connected to the detection cylinder in a sealed manner, and the second spring is located between the two. The detection disc is provided with a cylindrical through hole for the flow of damping oil. The connector is fixedly connected to the detection disc and slidably connected to the detection cylinder in a sealed manner. The elastic strip is fixedly connected to the lower part of the connector and contacts the threaded ring.

[0006] Furthermore, the plugging assembly includes a guide disk, a sealing cylinder, a rubber ring, and a plugging ball. The guide disk and the sealing cylinder are both limited and slidable within the blowout preventer housing. The blowout preventer housing and the guide disk are both provided with through holes in their middle portions for the light rod to pass through. The guide disk is fixedly connected to the sealing cylinder. A rubber ring that contacts the blowout preventer housing is fixedly connected to the outer periphery of the sealing cylinder. A guide channel is provided at the upper part of the blowout preventer housing. There is an angle between the central axis of the guide channel and the horizontal plane. The plugging ball is located within the guide channel. The plugging ball contacts the guide disk and is limited by the guide disk. The detection cylinder is fixedly connected to the guide disk.

[0007] Furthermore, one end of the elastic strip near the central axis of the connector is fixed to the connector, and a groove is provided on the upper side of the elastic strip near the central axis of the connector to facilitate bending of the elastic strip. The cross-section of the connector is inverted T-shaped.

[0008] Furthermore, the outer side of the blocking ball is wrapped with rubber.

[0009] Furthermore, the blowout shield is fixedly connected to an attraction ring, which is made of soft magnetic material, and the blocking ball is made of hard magnetic material, so that there is a magnetic attraction between the blocking ball and the attraction ring.

[0010] Furthermore, a plurality of limiting rods are fixedly connected to the upper side of the guide plate. All the limiting rods and connecting pieces are distributed in an arc shape at equal intervals on the upper side of the guide plate away from the sealing ball, and the aforementioned intervals are smaller than the diameter of the sealing ball. The limiting rods and the connecting pieces together are used to limit the movement range of the sealing ball.

[0011] Furthermore, a central connecting plate is slidably connected inside the bottom shell, and there are two packings, with the two packings located between the central connecting plate and the pressure applying member and between the central connecting plate and the bottom shell, respectively. A pressing inclined surface is provided on the lower side of the pressure applying member, and the central connecting plate is provided with two symmetrically distributed central connecting inclined surfaces. The pressing inclined surface and the central connecting inclined surface contact the adjacent packings and are used to guide the adjacent packings to deform inward.

[0012] Furthermore, it also includes an elastic element, which is rotatably connected inside the blowout preventer. The sealing cylinder is provided with a rectangular through hole. The sealing cylinder drives the elastic element to swing through the rectangular through hole. The elastic element contacts the side of the plugging ball away from the central axis of the blowout preventer.

[0013] Furthermore, it also includes a guide ring and a plurality of ring-shaped oscillating plates. The oscillating plates are hinged to the lower side of the guide disk, and the guide ring is fixed inside the blowout preventer. The oscillating plates are in contact with the guide ring. The guide ring is used to guide the oscillating plates to oscillate and to block the through holes on the guide disk. The upper side of the guide disk and the upper side inside the blowout preventer are both provided with frustum-shaped inclined surfaces. The frustum-shaped inclined surfaces of the guide disk and the blowout preventer are used to jointly guide the plugging ball toward the through holes of both.

[0014] Furthermore, a plurality of support bars arranged in a ring are fixed to the lower side of the guide plate, the number of which is equal to the number of the oscillating plates, and the support bars are used to provide support for adjacent oscillating plates.

[0015] Compared with the prior art, the present invention has the following advantages: The present invention utilizes the phenomenon that the packing loses its internal support and compresses rapidly due to the breakage of the polished rod to determine whether the polished rod has broken off, thereby determining whether the wellhead needs to be sealed. In this way, the blowout preventer does not need to be in direct contact with the polished rod, avoiding wear between the blowout preventer and the polished rod, reducing the frequency of inspection and maintenance, and slowing down the wear rate of the polished rod, thus reducing maintenance costs and workload.

[0016] By utilizing the deformability of rubber, the contact area between the sealing ball and the blowout preventer is increased. This also addresses the issue of impurities such as sand and gravel on the sealing surfaces of both components due to harsh environments, ensuring a good seal. Under the influence of magnetic attraction, the sealing ball is guided to seal the through holes on the blowout preventer, increasing the probability of a successful seal and thus enhancing the reliability of the device.

[0017] By utilizing the bending force of the elastic element to eject the sealing ball from the guide channel, the problem of the sealing ball becoming stuck due to prolonged stagnation in the guide channel is addressed, ensuring that the sealing ball can be moved out smoothly and improving the reliability of the sealing ball.

[0018] By using a swing plate to block the through-hole on the guide plate, the fluid entering the blowout preventer pushes the guide plate upward. Whether it is a rapid blowout or a slow overflow, the guide plate can assist in guiding the plugging ball to move towards the through-hole of the blowout preventer and the guide plate, so that the plugging ball blocks the through-hole of the blowout preventer and improves the reliability of the device. Attached Figure Description

[0019] Figure 1 This is a three-dimensional structural diagram of the present invention.

[0020] Figure 2 This is a three-dimensional structural cross-sectional view of the top shell and blowout shield of the present invention.

[0021] Figure 3 This is a three-dimensional structural cross-sectional view of the guide plate and sealing ball of the present invention.

[0022] Figure 4 This is a three-dimensional structural cross-sectional view of the detection cylinder and guide plate of the present invention.

[0023] Figure 5 This is a three-dimensional structural cross-sectional view of the detection cylinder and connector of the present invention.

[0024] Figure 6 This is a three-dimensional structural diagram of the guide plate and limiting rod of the present invention.

[0025] The numbers in the diagram are explained as follows: 1-Functional component, 2-Bottom shell, 3-Top shell, 4-Pressure application component, 401-Extrusion slope, 5-First spring, 6-Threaded ring, 7-Detection cylinder, 8-Detection disc, 9-Second spring, 10-Connector, 11-Elastic strip, 12-Blowout shield, 121-Guide channel, 13-Guide disc, 14-Sealing cylinder, 15-Rubber ring, 16-Blocking ball, 17-Suction ring, 18-Limiting rod, 19-Intermediate plate, 191-Intermediate slope, 20-Packing, 21-Elastic component, 211-Rectangular through hole, 22-Swing plate, 23-Guide ring, 24-Support strip. Detailed Implementation

[0026] The present invention will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can implement it after consulting this specification.

[0027] Example 1 This embodiment provides a blowout preventer wellhead sealing device that reduces maintenance costs and workload by changing the triggering method of existing blowout preventers.

[0028] See Figures 1 to 3A blowout preventer wellhead sealing device for broken rod includes: a functional component 1, a bottom shell 2, and a top shell 3. The functional component 1 consists of a self-aligning ball seat and a cylindrical half-packing. The self-aligning ball seat is used to maintain the coaxiality of the device with the polished rod, and the cylindrical half-packing is used to temporarily hold the polished rod and form a seal when replacing the upper parts. The self-aligning ball seat and the cylindrical half-packing are existing devices and will not be described in detail here. The bottom shell 2 is fixedly connected to the upper side of the functional component 1, and the top shell 3 is threadedly connected to the upper part of the bottom shell 2. Two packings 20 are provided inside the bottom shell 2, and the two packings 20 form a double seal for the polished rod. The upper side of the top shell 3 is threadedly connected to a blowout preventer shell 12. The bottom shell 2 and the top shell 3 are slidably connected together with a pressure applying component 4. The pressure applying component 4 contacts the upper packing 20 and is used to compress it. A first spring 5 is fixedly connected between the pressure applying component 4 and the top shell 3. The first spring 5 is used to maintain the pressure stability of the pressure applying component 4 on the packing 20. An observation window (not shown in the attached diagram) is provided on the side of the top shell 3. Through this window, operators can determine the position of the pressure-applying component 4 relative to the top shell 3, and thus judge whether the pressure applied by the pressure-applying component 4 to the packing 20 is within an appropriate range (the appropriate range here refers to the pressure range corresponding to the state where the packing 20 and the polished rod remain sealed). The upper side of the pressure-applying component 4 passes through the top shell 3 and is threadedly connected to a threaded ring 6. The blowout preventer 12 contains a detection component for detecting whether the polished rod has broken off and a sealing component for sealing itself. Multiple detection components can be used, and their number can be freely determined according to actual conditions. In this paper, three detection components are arranged in a ring to ensure that the threaded ring 6 and the guide plate 13 are subjected to uniform force in the circumferential direction.

[0029] The light rod passes through the functional component 1, the bottom shell 2, the packing 20, the pressure application component 4, the top shell 3, and the blowout preventer 12 in sequence from bottom to top.

[0030] See Figures 1 to 5 The detection assembly includes a detection cylinder 7, a detection disc 8, a second spring 9, a connector 10, and an elastic strip 11. The detection cylinder 7 is disposed inside the blowout preventer 12 and above the threaded ring 6. Damping oil is injected into the detection cylinder 7. The detection disc 8 is slidably and sealed inside the detection cylinder 7. The second spring 9 is fixed between the two. The detection disc 8 has a cylindrical through-hole for the flow of damping oil. The cylindrical through-hole is used to restrict the flow of damping fluid when the detection disc 8 moves rapidly downward. The connector 10 is fixed to the detection disc 8 and slidably and sealed to the detection cylinder 7. The elastic strip 11 is fixed to the lower part of the connector 10 and contacts the lower side of the threaded ring 6. The state of the polished rod is determined by the downward movement speed of the threaded ring 6.

[0031] The above setup enables the determination of whether the polished rod has broken off, based on the phenomenon that the packing 20 loses its internal support and compresses rapidly due to the breakage of the polished rod. This allows for the determination of whether wellhead sealing is necessary, thus eliminating the need for the blowout preventer to directly contact the polished rod, avoiding wear between the blowout preventer and the polished rod, reducing the frequency of inspection and maintenance, slowing down the wear rate of the polished rod, and reducing maintenance costs and workload.

[0032] See Figures 2 to 4 The plugging assembly includes: a guide plate 13, a sealing cylinder 14, a rubber ring 15, and a plugging ball 16. Both the guide plate 13 and the sealing cylinder 14 slide within the blowout preventer 12. Both the blowout preventer 12 and the guide plate 13 have through holes in their middle sections for the light bar to pass through. The guide plate 13 is fixedly connected to the sealing cylinder 14. A rubber ring 15, in contact with the blowout preventer 12, is fixedly connected to the outer periphery of the sealing cylinder 14. The rubber ring 15 controls the static friction between the sealing cylinder 14 and the blowout preventer 12, allowing the sealing cylinder 14 and the guide plate 13 to remain stationary relative to the blowout preventer 12 under the action of friction. A guide channel 121 is provided at the upper part of the blowout preventer 12. The horizontal height of the guide channel 121 gradually decreases from right to left. The plugging ball 16 is located within the guide channel 121, and the inclined state of the guide channel 121 causes the plugging ball 16 to have a tendency to roll to the left. See also... Figure 3 The blocking ball 16 contacts the guide plate 13 and is limited by the guide plate 13. The detection cylinder 7 is fixed to the guide plate 13, and the upper part of the connector 10 passes through the guide plate 13.

[0033] See Figure 5 The left end of the elastic strip 11 is fixed to the connector 10. A groove is provided on the upper left side of the elastic strip 11, making the thickness of the elastic strip 11 at the groove less than the thickness of the rest, which facilitates the bending of the elastic strip 11. The connector 10 has an inverted T-shaped cross-section and contacts the lower side of the elastic strip 11, providing support for the elastic strip 11. Relying on the groove of the elastic strip 11 and the support of the connector 10, the elastic strip 11 has different bending strengths in the upward and downward directions. In this way, on the one hand, it is convenient to move the threaded ring 6 to the upper side of the elastic strip 11, and on the other hand, the elastic strip 11 can be used to pull the connector 10 downward.

[0034] See Figure 3The plugging ball 16 is wrapped with rubber on its outer side. An attraction ring 17 is fixed to the blowout preventer 12. The attraction ring 17 is made of soft magnetic material, while the plugging ball 16 is made of hard magnetic material, creating a magnetic attraction between the plugging ball 16 and the attraction ring 17. The diameter of the plugging ball 16 is larger than the diameter of the through hole on the guide plate 13 and the inner diameter of the attraction ring 17. Utilizing the deformability of rubber, the contact area between the plugging ball 16 and the blowout preventer 12 is increased. This also addresses the presence of sand and other impurities on the sealing surfaces of both components due to harsh environments, ensuring a good seal. Under the action of magnetic attraction, the guide plugging ball 16 seals the through hole on the blowout preventer 12, increasing the probability of a successful seal and thus enhancing the reliability of the device.

[0035] See Figures 2 to 4 and Figure 6 Multiple limiting rods 18 are fixed to the upper side of the guide plate 13. All the limiting rods 18 and all the connecting parts 10 are distributed in an arc shape at equal intervals on the left side of the upper side of the guide plate 13, and the above intervals are smaller than the diameter of the plugging ball 16. The limiting rods 18 and the connecting parts 10 are used together to limit the movement range of the plugging ball 16, reduce the movable range of the plugging ball 16, increase the probability of the plugging ball 16 blocking the through hole on the blowout preventer 12, and improve the reliability of the device.

[0036] See Figure 2 and Figure 3 A middle connecting plate 19 is slidably connected inside the bottom shell 2. Two packings 20 are located between the middle connecting plate 19 and the pressure member 4 and between the middle connecting plate 19 and the bottom shell 2, respectively. A pressing slope 401 is provided on the lower side of the pressure member 4. The horizontal height of each point on the pressing slope 401 gradually decreases in the direction from the inside to the outside. The middle connecting plate 19 is provided with two symmetrically distributed middle connecting slopes 191. The thickness of the middle connecting plate 19 gradually increases in the direction from the inside to the outside. The pressing slope 401 and the middle connecting slope 191 contact the adjacent packings 20 respectively and are used to guide the adjacent packings 20 to deform inward, so as to increase the deformation range of the packings 20 after losing the internal support provided by the smooth rod.

[0037] Without affecting oil production operations, the wellhead sealing device provided by this invention can automatically adjust the state of the two packing glands 20 inside the bottom shell 2 according to the actual wellhead conditions. In the event of polished rod breakage, if the packing gland 20 located on the upper side of the intermediate connecting plate 19 has sufficient deformation to allow the pressure application component 4 to move, the packing gland 20 located on the lower side of the intermediate connecting plate 19 can exist independently. That is, the intermediate connecting plate 19 and the bottom shell 2 can be considered as fixedly connected. The packing gland 20 located on the upper side of the intermediate connecting plate 19 can monitor the state of the middle polished rod and determine whether the polished rod has broken off while providing a polished rod sealing effect. The packing gland 20 originally located on the lower side of the intermediate connecting plate 19 exists independently and provides a polished rod sealing effect. Moreover, this packing gland 20 can be moved to the upper side of the blowout preventer 12 according to the actual wellhead conditions.

[0038] The initial adjustment and daily maintenance process after adopting the above settings is as follows: The staff will install the functional component 1, bottom shell 2, top shell 3, pressure component 4, first spring 5, middle connecting plate 19 and packing 20, and then install the threaded ring 6 to the upper part of the pressure component 4.

[0039] Adjust the positions of the guide plate 13, sealing cylinder 14, and sealing ball 16 within the blowout preventer 12. Then, move the blowout preventer 12 and its internal components together above the top shell 3. By rotating the blowout preventer 12, thread it onto the top shell 3. During the threaded connection, the guide plate 13 and sealing cylinder 14 remain stationary with the blowout preventer 12 under the friction between the rubber ring 15 and the blowout preventer 12. The blowout preventer 12 and its internal components move downward together. The guide plate 13 drives the detection cylinder 7, detection plate 8, second spring 9, connector 10, and elastic strip 11 to move downward together, so that the distance between the elastic strip 11 and the threaded ring 6 gradually decreases.

[0040] After the blowout preventer 12 is installed, rotate the blowout preventer 12. The blowout preventer 12 drives the top shell 3 to rotate, thereby adjusting the compression amplitude of the first spring 5. At the same time, change the distance between the threaded ring 6 and the top shell 3, so that the threaded ring 6 moves upward relative to the top shell 3 (during this period, the operator observes the relative position of the pressure application component 4 and the top shell 3 through the observation window on the top shell 3, thus knowing the distance between the threaded ring 6 and the top shell 3). The distance between the threaded ring 6 and the elastic strip 11 further decreases, and eventually the two come into contact. As the threaded ring 6 continues to move upward, the threaded ring 6 compresses the elastic strip 11, causing the elastic strip 11 to bend elastically upward from its groove position (during this process, the guide plate 13 and the sealing cylinder 14 remain stationary relative to the blowout preventer 12), until the threaded ring 6 moves above the elastic strip 11 and loses contact with the elastic strip 11, after which the elastic strip 11 returns to its original shape under its own elasticity. At this point, rotate the top shell 3 in the opposite direction to move the threaded ring 6 down and make it contact the upper side of the elastic strip 11. This completes the installation and initial adjustment of the device (at this point, the distance between the threaded ring 6 and the top shell 3 is greater than the height of the upper surface of the guide plate 13 above the inlet of the guide channel 121).

[0041] As the guide rod reciprocates, it causes wear on the packing 20, causing the pressure application 4 and the threaded ring 6 to slowly move downwards under the action of the first spring 5, until the distance between the threaded ring 6 and the top shell 3 is equal to the height of the upper surface of the guide plate 13 above the inlet of the guide channel 121 (see...). Figure 3During the adjustment process, the operator rotates the top shell 3, causing it to move downwards and compress the first spring 5. Simultaneously, the pressure-applying component 4 and the threaded ring 6 move upwards relative to the top shell 3 until the distance between the threaded ring 6 and the top shell 3 returns to the initial adjusted state. This increases the compressive force exerted by the first spring 5 on the pressure-applying component 4, thereby increasing the pressure on the packing 20, improving the compressive force between the packing 20 and the polished rod, maintaining the stability of the seal between the packing 20 and the polished rod, and utilizing the energy stored in the first spring 5 to counteract the wear caused by the movement of the polished rod on the packing 20, thus keeping the compressive force between the packing 20 and the polished rod within a suitable range.

[0042] As the threaded ring 6 slowly moves downward, it drives the connector 10 and the detection disc 8 downward through the elastic strip 11, compressing the second spring 9. Simultaneously, the damping fluid located below the detection disc 8 in the detection cylinder 7 flows through the cylindrical through-hole of the detection disc 8 to the upper side of the detection disc 8. During the process described above, the low movement speed of the detection disc 8 allows the damping fluid sufficient time to pass through it. After the operator readjusts the position of the top shell 3 and restores the distance between the threaded ring 6 and the top shell 3, the detection disc 8, connector 10, and elastic strip 11 slowly move upward under the action of the second spring 9 and eventually return to their original positions.

[0043] The procedure for handling rod breakage after the above setup is as follows: When the rod breaks off, the packing 20 loses the internal support provided by the rod, causing it to "collapse" inward under the pressure of the pressure member 4, reducing its height. During this process, the pressure member 4 and the threaded ring 6 move downward rapidly, which in turn drives the detection plate 8 to move downward rapidly. Due to the high speed of the detection plate 8, the damping fluid in the detection cylinder 7 does not have enough time to flow through the detection plate 8, causing the detection plate 8 to drive the detection cylinder 7 downward. The detection cylinder 7 then drives the guide plate 13 and the sealing cylinder 14 downward, overcoming the static friction between the rubber ring 15 and the blowout preventer 12. The downward distance of the guide plate 13 is at least greater than its height above the guide channel 121, causing the guide plate 13 to release its restriction on the sealing ball 16, allowing the sealing ball 16 to move out of the guide channel 121 under the action of magnetic attraction and gravity.

[0044] As the guide plate 13 moves downward, the guide plate 13 also moves the limiting rod 18 on it downward. When the plugging ball 16 moves out of the guide channel 121 and falls into the upper side of the guide plate 13, the limiting rod 18 and the connector 10 together limit the movement path of the plugging ball 16, guiding the plugging ball 16 to be located at the through hole of the guide plate 13 and the blowout preventer 12, thereby increasing the probability that the plugging ball 16 will successfully plug the through hole of the blowout preventer 12.

[0045] After the plugging ball 16 moves from the guide channel 121 into the blowout preventer 12, the plugging ball 16 adheres to the suction ring 17 under the action of magnetic attraction between it and the suction ring 17. In this way, the plugging ball 16 seals the through hole on the blowout preventer 12, reducing the probability of a blowout accident.

[0046] Example 2 This embodiment improves the reliability of the blocking ball 16 moving out of the guide channel 121 based on embodiment 1.

[0047] See Figures 2 to 4 It also includes: an elastic element 21, which is rotatably connected inside the blowout preventer 12; a sealing cylinder 14 is provided with a rectangular through hole 211; the left end of the elastic element 21 passes through the rectangular through hole 211; the sealing cylinder 14 drives the elastic element 21 to swing through the rectangular through hole 211; and the elastic element 21 contacts the right side of the sealing ball 16.

[0048] The above settings enable the elastic element 21 to bend and store force, and eject the blocking ball 16 from the guide channel 121. This addresses the situation where the blocking ball 16 becomes stuck in the guide channel 121 for a long time, which would cause the movement of the blocking ball 16 to be obstructed. This ensures that the blocking ball 16 can be moved out smoothly and improves the reliability of the blocking ball 16.

[0049] Example 3 This embodiment provides a function to deal with crude oil spill accidents after the polished rod breaks off, based on embodiment 2.

[0050] See Figure 3 and Figure 4 It also includes a guide ring 23 and multiple ring-shaped oscillating plates 22. The number of oscillating plates 22 can be flexibly adjusted according to the diameter of the through hole on the guide plate 13. Here, the number of guide plates 13 is eight. The oscillating plates 22 are made of soft magnetic material, which allows the oscillating plates 22 to be attracted and closed by the plugging ball 16, improving the reliability of the oscillating plates 22 in blocking the through hole on the guide plate 13. The oscillating plates 22 are hinged to the lower side of the guide plate 13, and the guide ring 23 is fixed inside the blowout preventer 12. The oscillating plates 22 are in contact with the guide ring 23. The guide ring 23 is used to guide the oscillating plates 22 to swing and block the through hole on the guide plate 13. The upper side of the guide plate 13 and the upper side inside the blowout preventer 12 are both provided with frustum-shaped inclined surfaces. The frustum-shaped inclined surfaces of the guide plate 13 and the blowout preventer 12 are used together to guide the plugging ball 16 to the through hole of both.

[0051] The above settings enable the following: after the polished rod is detected to have broken off, the swing plate 22 blocks the through hole on the guide plate 13, causing the fluid entering the blowout preventer 12 to push the guide plate 13 upward. Whether it is a rapid blowout or a slow overflow, the sealing ball 16 can be guided by the frustum-shaped inclined surface of the guide plate 13 to move towards the through hole of the blowout preventer 12 and the guide plate 13, so that the sealing ball 16 can block the through hole of the blowout preventer 12, thereby improving the reliability of the device.

[0052] See Figure 4 Multiple support bars 24 are fixedly connected to the lower side of the guide plate 13 in a ring. The number of support bars 24 is equal to the number of swing plates 22. The support bars 24 are used to provide support for adjacent swing plates 22 and limit the maximum angle that adjacent swing plates 22 can swing, so that all swing plates 22 can be combined into a pyramid shape. The pyramid-shaped swing plates 22 disperse the extrusion force of the fluid applied to the swing plates 22, enhance the pressure tolerance range of the swing plates 22, that is, increase the upward extrusion force of the guide plate 13 on the sealing ball 16.

[0053] The process after the above setup is as follows: During the downward movement of the guide plate 13 and the sealing cylinder 14, the sealing cylinder 14 compresses the left end of the elastic element 21 downward through the rectangular through hole 211, causing the elastic element 21 to swing. During this process, since the sealing ball 16 is still limited by the guide plate 13, the upper right end of the elastic element 21 only has the tendency to push the sealing ball 16 to the left. The elastic element 21 bends and deforms and stores force until the guide plate 13 releases the limitation on the sealing ball 16. Then, under its own elasticity, the elastic element 21 quickly pushes the sealing ball 16 out of the guide channel 121. This ensures that the sealing ball 16 can be moved out smoothly, improving the reliability of the device.

[0054] During the downward movement of the guide plate 13, the guide plate 13 drives the oscillating vane 22 downward. The oscillating vane 22 is squeezed and oscillates by the guide ring 23. At the same time, the oscillating vane 22 is affected by the magnetic attraction of the plugging ball 16, and eventually oscillates to a state of contact with the support bar 24. At this time, the eight oscillating vanes 22 together form an octagonal pyramid shape, blocking the through hole on the guide plate 13. In this state, the guide plate 13 and the oscillating vane 22 divide the inside of the blowout preventer 12 into upper and lower parts. In this way, whether it is a rapid blowout or a slow overflow, the guide plate 13 can be pushed upward. By using the truncated cone-shaped inclined surface of the guide plate 13 and the blowout preventer 12 to squeeze the plugging ball 16 to move, the plugging ball 16 finally blocks the through hole on the blowout preventer 12 and the guide plate 13, thus improving the applicability of this device and improving the reliability of the plugging by the plugging ball 16.

[0055] Although embodiments of the invention have been shown and described, those skilled in the art will recognize that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention.

Claims

1. A wellhead sealing device for preventing blowout due to broken rod, characterized in that: include: Functional component (1), the upper side of which is fixedly connected to a bottom shell (2), a packing (20) is provided inside the bottom shell (2), the upper part of the bottom shell (2) is threadedly connected to a top shell (3), the upper side of the top shell (3) is threadedly connected to a blowout preventer (12), the bottom shell (2) and the top shell (3) are jointly and slidably connected to a pressure member (4) for squeezing the packing (20), a first spring (5) is fixedly connected between the pressure member (4) and the top shell (3), the upper side of the pressure member (4) passes through the top shell (3) and is threadedly connected to a threaded ring (6), and a detection component and a sealing component are provided inside the blowout preventer (12); The detection assembly includes a detection cylinder (7), a detection disc (8), a second spring (9), a connector (10), and an elastic strip (11). The detection cylinder (7) is disposed inside the blowout preventer (12). Damping oil is injected into the detection cylinder (7). The detection disc (8) is slidably connected to the detection cylinder (7). The second spring (9) is located between the detection cylinder (7) and the detection disc (8). A cylindrical through hole for the flow of damping oil is provided on the detection disc (8). The connector (10) is fixed to the detection disc (8) and slidably connected to the detection cylinder (7). The elastic strip (11) is fixed to the lower part of the connector (10) and contacts the threaded ring (6). The plugging assembly includes a guide plate (13), a sealing cylinder (14), a rubber ring (15), and a plugging ball (16). The guide plate (13) and the sealing cylinder (14) are both limited and slidable within the blowout preventer (12). The blowout preventer (12) and the guide plate (13) are both provided with through holes for the light rod to pass through. The guide plate (13) is fixedly connected to the sealing cylinder (14). The outer periphery of the sealing cylinder (14) is fixedly connected to the rubber ring (15) that contacts the blowout preventer (12). The upper part of the blowout preventer (12) is provided with a guide channel (121). There is an angle between the central axis of the guide channel (121) and the horizontal plane. The plugging ball (16) is located in the guide channel (121). The plugging ball (16) contacts the guide plate (13) and is limited by the guide plate (13). The detection cylinder (7) is fixedly connected to the guide plate (13).

2. The wellhead sealing device for preventing blowout due to rod breakage according to claim 1, characterized in that: The elastic strip (11) is fixed to the connector (10) at one end near the central axis of the connector (10). A groove is provided on the upper side of the elastic strip (11) near the central axis of the connector (10) to facilitate bending of the elastic strip (11). The cross section of the connector (10) is inverted T-shaped.

3. The wellhead sealing device for preventing blowout due to broken rod as described in claim 2, characterized in that: The outer side of the blocking ball (16) is wrapped with rubber.

4. The wellhead sealing device for preventing blowouts due to rod breakage according to claim 3, characterized in that: The blowout shield (12) is fixed with an attraction ring (17), which is made of soft magnetic material and the plugging ball (16) is made of hard magnetic material, so that there is a magnetic attraction between the plugging ball (16) and the attraction ring (17).

5. A wellhead sealing device for preventing blowout due to rod breakage according to claim 4, characterized in that: Multiple limiting rods (18) are fixedly connected to the upper side of the guide plate (13). All the limiting rods (18) and the connecting pieces (10) are distributed in an arc shape at equal intervals on the upper side of the guide plate (13) away from the sealing ball (16), and the above interval is smaller than the diameter of the sealing ball (16). The limiting rods (18) and the connecting pieces (10) together are used to limit the movement range of the sealing ball (16).

6. The wellhead sealing device for preventing blowout due to rod breakage according to claim 5, characterized in that: The bottom shell (2) is slidably connected to a middle connecting plate (19). There are two packings (20), and the two packings (20) are located between the middle connecting plate (19) and the pressure member (4) and between the middle connecting plate (19) and the bottom shell (2), respectively. The pressure member (4) is provided with a pressing slope (401) on its lower side. The middle connecting plate (19) is provided with two symmetrically distributed middle connecting slopes (191). The pressing slope (401) and the middle connecting slope (191) are in contact with the adjacent packings (20) respectively, and are used to guide the adjacent packings (20) to deform inward.

7. A wellhead sealing device for preventing blowouts due to rod breakage according to claim 6, characterized in that: Also includes: The elastic element (21) is rotatably connected inside the blowout preventer (12). The sealing cylinder (14) is provided with a rectangular through hole (211). The sealing cylinder (14) drives the elastic element (21) to swing through the rectangular through hole (211). The elastic element (21) contacts the side of the plugging ball (16) away from the central axis of the blowout preventer (12).

8. A wellhead sealing device for preventing blowouts due to rod breakage according to claim 7, characterized in that: Also includes: A guide ring (23) and a plurality of ring-shaped oscillating plates (22) are arranged in a ring. The oscillating plates (22) are hinged to the lower side of the guide disk (13). The guide ring (23) is fixed inside the blowout preventer (12). The oscillating plates (22) are in contact with the guide ring (23). The guide ring (23) is used to guide the oscillating plates (22) to swing and block the through holes on the guide disk (13). The upper side of the guide disk (13) and the upper side inside the blowout preventer (12) are both provided with frustum-shaped inclined surfaces. The frustum-shaped inclined surfaces of the guide disk (13) and the blowout preventer (12) are used to guide the plugging ball (16) to the through holes of both.

9. A wellhead sealing device for preventing blowouts due to rod breakage according to claim 8, characterized in that: The lower side of the guide plate (13) is fixed with a plurality of ring-shaped support bars (24), the number of which is equal to the number of the swing plates (22), and the support bars (24) are used to provide support for the adjacent swing plates (22).

Images