Blowout preventer special for SAGD wellhead

Abstract

The invention relates to the technical field of wellhead blowout preventers, in particular to a special blowout preventer for an SAGD (steam assisted gravity drainage) wellhead, which comprises a cylindrical valve core, a control unit and a valve body with an axial through hole in the middle. The device is reasonable and compact in structure and convenient to use, the temperature of the valve body can be monitored in real time through the temperature monitoring module, after a polished rod is broken and disengaged, when the valve body temperature collected by the control unit exceeds a set threshold value, the control unit can automatically control the rotating motor to act, and the cylindrical valve element is driven by the valve rod to rotate by 90 degrees; the axis of the polish rod mounting hole and the axis of the axial through hole are changed into a vertical state from a coaxial state, and the axial through hole is blocked by the outer side surface of the cylindrical valve core parallel to the axial direction of the polish rod mounting hole, so that blowout is quickly controlled, and underground high-temperature liquid and gas are prevented from being ejected out of a wellhead from the axial through hole and the polish rod mounting hole; the oil and gas leakage amount is greatly reduced, the risk of causing environmental pollution accidents is greatly reduced, the personal safety of operators can be effectively prevented from being harmed, and the well control risk is greatly reduced.

Description

Technical Field

[0001] This invention relates to the field of wellhead blowout preventer technology, and is a SAGD wellhead-specific blowout preventer device. Background Technology

[0002] Steam-assisted gravity drainage (SAGD) is an advanced oil recovery technology. Its mechanism involves injecting steam into an injection well, creating a steam chamber around the well. This chamber expands upwards and laterally, exchanging heat with the crude oil in the reservoir. The heated crude oil and steam condensate are then discharged under gravity into the horizontal production well below. Due to its dual-horizontal-well development method, SAGD oil recovery technology features high production, a high oil-to-steam ratio, and significantly higher oil recovery rates and ultimate recovery rates compared to conventional extra-heavy oil development methods.

[0003] As oilfield development progresses, the steam chamber expands, and the energy stored in the formation increases. When a SAGD production well experiences rod breakage during normal production, the remaining rod falls into the wellbore below the packing box. At this point, the wellhead is out of control, and a high-temperature liquid column erupts from the top of the packing box, while a large amount of high-temperature steam from the downhole steam chamber is ejected from the wellhead, resulting in a blowout. Currently, most wellhead blowout prevention devices in China require manual operation for well sealing, leading to high well control risks, slow sealing speeds, and potential safety hazards for workers, as well as the risk of large-scale oil and gas leaks causing environmental pollution accidents. Summary of the Invention

[0004] This invention provides a blowout preventer device for SAGD wellheads, which overcomes the shortcomings of the prior art. It can effectively solve the problems of slow manual well sealing, high well control risk, easy injury to the personal safety of operators, and large-scale oil and gas leakage leading to environmental pollution accidents in existing SAGD oil well blowout preventer measures.

[0005] The technical solution of this invention is achieved through the following measures: A blowout preventer for SAGD wellheads includes a cylindrical valve core, a control unit, and a valve body with an axial through hole in the middle. An outer boss is provided on the outer right side of the valve body, and a valve hole opening to the right is provided in the middle of the right side of the outer boss. The left end of the valve hole passes through the axial through hole and stops to the left of the axial through hole. A cylindrical valve core is fitted inside the left side of the valve hole. A through-hole for mounting a smooth rod is provided on the cylindrical valve core corresponding to the position of the axial through hole, and the inner diameter of the through-hole is equal to the inner diameter of the axial through hole. A valve rod with its right end located to the right of the outer boss is fixedly installed in the middle of the right end face of the cylindrical valve core. The outer left side of the valve rod is connected to the valve hole. A valve stem sealing assembly is fixedly installed between the inner sides of the right side. The valve stem sealing assembly can seal the gap between the outer side of the valve stem and the inner side of the right side of the valve hole without affecting the rotation of the valve stem and the cylindrical valve core. A rotary drive unit is connected to the outer side of the right end of the valve stem. The rotary drive unit can drive the cylindrical valve core to rotate 90° through the valve stem, so that the axis of the smooth rod mounting hole is perpendicular to the axis of the axial through hole. A temperature monitoring module that can monitor the valve body temperature in real time is fixedly installed on the outer side of the front part of the valve body. The control unit can collect the valve body temperature in real time. When the valve body temperature exceeds the set threshold, the control unit can automatically control the rotary drive unit to drive the cylindrical valve core of the valve body to rotate 90° and then seal the axial through hole.

[0006] The following are further optimizations and / or improvements to the above-mentioned technical solution: A manual rotation component that allows manual rotation of the valve stem can be provided on the outer side of the valve stem at the position corresponding to the rotary drive unit and the valve stem sealing assembly. The manual rotation component may include a manual handle, a limit lever, an upper limit block, and a lower limit block. A limit lever is fixedly installed on the upper side of the valve stem at the position corresponding to the right side of the valve stem sealing assembly. A manual handle is connected to the outer side of the valve stem at the position corresponding to the right side of the limit lever. An upper limit block is fixedly installed on the upper right side of the valve stem sealing assembly at the rear side of the limit lever. A lower limit block is fixedly installed on the front right side of the valve stem sealing assembly, and the included angle between the lower limit block and the upper limit block is 90°. The manual handle can drive the limit lever to rotate between the upper limit blocks through the valve stem.

[0007] The valve stem sealing assembly mentioned above may include a pressure plate, a sealing packing, and a gland. The pressure plate, sealing packing, and gland, which are fitted onto the outside of the valve stem, are fixedly installed on the inner right side of the valve hole from left to right.

[0008] The outer side of the right end of the aforementioned pressure cap may be provided with an outer ring platform whose left end abuts against the right end face of the outer protrusion. The outer side of the outer ring platform may be provided with a first wrench part for easy locking of a wrench. The outer side of the pressure cap corresponding to the left side of the outer ring platform and the inner side of the valve hole may be connected together by threads. The outer side of the pressure plate and the inner side of the valve hole may be connected together by threads at the corresponding positions. The right side of the pressure plate may have several wrench holes with openings facing right evenly distributed along the circumference.

[0009] The aforementioned rotary drive unit may include a rotary motor and a speed reduction device. The speed reduction device is driven to the outer side of the right end of the valve stem, and the input end of the speed reduction device is driven to the output end of the rotary motor.

[0010] The lower inner side of the valve body may be provided with a packing box mounting inner ring groove, and the upper inner side of the packing box mounting inner ring groove may be a lubricating oil storage area.

[0011] The upper outer side of the valve body may be provided with a second wrench part for easy locking of a wrench.

[0012] This invention features a reasonable and compact structure, making it easy to use. It can monitor the valve body temperature in real time via a temperature monitoring module. After the polished rod breaks off, when the valve body temperature collected by the control unit exceeds a set threshold, the control unit automatically controls the rotary motor to rotate the cylindrical valve core 90° via the valve stem. This changes the axis of the polished rod mounting hole from coaxial to perpendicular with the axis of the axial through hole. The outer surface of the cylindrical valve core, parallel to the axis of the polished rod mounting hole, blocks the axial through hole, thereby quickly controlling the blowout and preventing high-temperature liquids and gases from ejecting from the axial through hole and polished rod mounting hole into the wellhead. This significantly reduces oil and gas leakage and greatly lowers the risk of environmental pollution accidents. Furthermore, no manual operation is required during use, effectively preventing injury to personnel and greatly reducing well control risks. Attached Figure Description

[0013] Appendix Figure 1 This is a schematic diagram of the main sectional view of Embodiments 1-7 of the present invention.

[0014] Appendix Figure 2 For the appendix Figure 1 A schematic diagram of the three-dimensional structure.

[0015] Appendix Figure 3 For the appendix Figure 1 A three-dimensional structural diagram of the cylindrical valve core and valve stem.

[0016] Appendix Figure 4 For the appendix Figure 1 A three-dimensional structural diagram of the medium-pressure cover.

[0017] The codes in the attached diagram are as follows: 1 is cylindrical valve core, 2 is axial through hole, 3 is valve body, 4 is external boss, 5 is valve hole, 6 is smooth rod mounting hole, 7 is valve stem, 8 is rotary drive unit, 9 is temperature monitoring module, 10 is manual handle, 11 is limit lever, 12 is upper limit block, 13 is lower limit block, 14 is pressure plate, 15 is sealing packing, 16 is pressure cap, 17 is outer ring platform, 18 is first wrench part, 19 is wrench hole, 20 is packing box mounting inner ring groove, 21 is lubricating oil storage area, 22 is second wrench part, 23 is smooth rod, 24 is upper packing box, and 25 is square transmission part. Detailed Implementation

[0018] The present invention is not limited to the following embodiments, and the specific implementation can be determined according to the technical solution of the present invention and the actual situation.

[0019] In this invention, for ease of description, the description of the relative positions of the components is based on the appendix to the specification. Figure 1 The layout is described using a diagrammatic method, such as front, back, top, bottom, left, right, etc. The positional relationships are determined based on the layout direction of the attached diagram in the instruction manual.

[0020] The present invention will be further described below with reference to embodiments and accompanying drawings: Example 1: As shown in the attached document Figures 1 to 3 As shown, the SAGD wellhead blowout preventer includes a cylindrical valve core 1, a control unit, and a valve body 3 with an axial through hole 2 in the middle. An outer boss 4 is provided on the outer right side of the valve body 3. A valve hole 5 opening to the right is provided on the middle right side of the outer boss 4, and the left end of the valve hole 5 passes through the axial through hole 2 and stops to the left of the axial through hole 2. A cylindrical valve core 1 is fitted inside the left side of the valve hole 5. A through-hole 6 for the smooth rod is provided on the cylindrical valve core 1 corresponding to the position of the axial through hole 2, and the inner diameter of the through-hole 6 is equal to the inner diameter of the axial through hole 2. A valve stem 7 with its right end located to the right of the outer boss 4 is fixedly installed on the middle right end face of the cylindrical valve core 1. The outer left side of the valve stem 7 is fixed to the inner right side of the valve hole 5. A valve stem sealing assembly is installed, which can seal the gap between the outer side of the valve stem 7 and the inner right side of the valve hole 5 without affecting the rotation of the valve stem 7 and the cylindrical valve core 1. A rotary drive unit 8 is connected to the outer right end of the valve stem 7. The rotary drive unit 8 can drive the cylindrical valve core 1 to rotate 90° through the valve stem 7, so that the axis of the smooth rod mounting hole 6 is perpendicular to the axis of the axial through hole 2. A temperature monitoring module 9 that can monitor the temperature of the valve body 3 in real time is fixedly installed on the outer front part of the valve body 3. The control unit can collect the temperature of the valve body 3 in real time. When the temperature of the valve body 3 exceeds the set threshold, the control unit can automatically control the rotary drive unit 8 to drive the cylindrical valve core 1 of the valve body 3 to rotate 90° and then seal the axial through hole 2.

[0021] Depending on the requirements, the valve body 3 is usually made of metal to achieve good heat dissipation; the temperature monitoring module 9 can be implemented using existing temperature sensors, temperature monitors, or temperature transmitters, and the temperature sensor can be the FST600-103 platinum resistance temperature sensor from First Sensors; the control unit can be implemented based on existing PLCs, microcontrollers, or computers, and the control unit integrates a temperature acquisition module, which is existing technology; the rotary drive unit 8 can be a servo motor or stepper motor, which can be connected to a reducer for transmission, or it can be implemented using a rotary encoder, a rotary motor, and a reducer, all of which are existing technologies. It can also be a servo motor or other control motor from the existing geared motor category.

[0022] The valve stem sealing assembly can be achieved as follows: a sealing inner ring groove is provided on the inner right side of the valve hole 5. From left to right, a sealing gasket or sealing packing and a T-shaped gland are arranged in the sealing inner ring groove, which are fitted onto the outer side of the valve stem 7. The outer left side of the T-shaped gland and the inner side of the sealing inner ring groove can be connected together by threads. The left end of the T-shaped gland abuts against the sealing gasket or sealing packing. Rotating the T-shaped gland can adjust the tightness between the sealing gasket or sealing packing and the valve stem 7, ensuring that the sealing gasket or sealing packing does not affect the normal rotation of the valve stem 7 and does not leak liquid.

[0023] The inner diameters of the axial through hole 2 and the polished rod mounting hole 6 are matched with the outer diameter of the polished rod 23, allowing the polished rod 23 to move up and down within the axial through hole 2 and the polished rod mounting hole 6. After passing through the axial through hole 2 and the polished rod mounting hole 6, the polished rod 23 can work normally under the drive of the pumping unit and will not affect the normal production of the oil well.

[0024] Currently, SAGD production wells generally use dual-stage sealing packing boxes. To facilitate the connection of this invention with the external thread on the upper outer side of the upper packing box 24, the inner side of the lower end of the valve body 3 can be provided with a threaded inner annular groove. The inner thread of the threaded inner annular groove is compatible with the external thread on the upper part of the upper packing box 24 in the prior art. After this invention is installed on the existing packing box, it can realize all the functions of the original packing gland without affecting the normal function of the original packing box and the normal operation of the pumping unit.

[0025] When the invention is fully open during use: After removing the packing gland cap of the upper packing box 24, screw the present invention onto the upper outer side of the upper packing box 24. At this time, the axis of the polished rod mounting hole 6 is coaxial with the axis of the axial through hole 2. Pass the lower end of the polished rod 23 through the upper inner side of the axial through hole 2, the polished rod mounting hole 6, the lower inner side of the axial through hole 2, the middle inner side of the upper packing box 24, and the middle inner side of the lower packing box from top to bottom. The original double-stage sealing packing box can still seal the annular space between the wellhead and the polished rod 23 to prevent oil leakage and enable the polished rod 23 to work normally.

[0026] Close this invention: When the polished rod 23 breaks off, a blowout occurs, and high-temperature liquid and gas in the well are ejected from the axial through hole 2. The temperature monitoring module 9 detects a rapid rise in the temperature of the valve body 3. The temperature of the valve body 3 collected by the control unit exceeds the set threshold. The control unit automatically controls the rotary drive unit 8 to drive the cylindrical valve core 1 to rotate 90° through the valve stem 7, so that the axis of the polished rod mounting hole 6 is perpendicular to the axis of the axial through hole 2. The axial through hole 2 is sealed by the front or rear side of the cylindrical valve core 1, thereby quickly controlling the blowout.

[0027] This invention features a reasonable and compact structure, making it easy to use. It can monitor the temperature of the valve body 3 in real time via the temperature monitoring module 9. After the polished rod 23 breaks off, when the temperature of the valve body 3 collected by the control unit exceeds a set threshold, the control unit automatically controls the rotary drive unit 8 to rotate. This drives the cylindrical valve core 1 to rotate 90° via the valve stem 7, changing the axis of the polished rod mounting hole 6 from coaxial to perpendicular with the axis of the axial through hole 2. The outer surface of the cylindrical valve core 1, parallel to the axis of the polished rod mounting hole 6, blocks the axial through hole 2, thereby quickly controlling the blowout and preventing high-temperature liquids and gases from spraying out of the wellhead from the axial through hole 2 and the polished rod mounting hole 6. This significantly reduces oil and gas leakage and greatly lowers the risk of environmental pollution accidents. During use, no manual operation by personnel is required, effectively preventing injury to personnel and greatly reducing well control risks.

[0028] The above-mentioned SAGD wellhead-specific blowout preventer can be further optimized and / or improved according to actual needs: Example 2: As shown in the attached document Figures 1 to 4 As shown, a manual rotation assembly is provided on the outer side of the valve stem 7 at the position corresponding to the position between the rotary drive unit 8 and the valve stem sealing assembly, which allows manual rotation of the valve stem 7. The manual rotation assembly includes a manual handle 10, a limit lever 11, an upper limit block 12, and a lower limit block 13. The limit lever 11 is fixedly installed on the upper side of the valve stem 7 at the position corresponding to the right side of the valve stem sealing assembly. The manual handle 10 is connected to the outer side of the valve stem 7 at the position corresponding to the right side of the limit lever 11. The upper limit block 12 is fixedly installed on the upper right side of the valve stem sealing assembly at the rear side of the limit lever 11. The lower limit block 13 is fixedly installed on the front right side of the valve stem sealing assembly, and the included angle between the lower limit block 13 and the upper limit block 12 is 90°. The manual handle 10 can drive the limit lever 11 to rotate between the upper limit blocks 12 through the valve stem 7.

[0029] With this setup, when the operator finds that the polished rod 23 has broken off at the work site and the high-temperature liquid and gas have not yet sprayed out of the wellhead, the operator can hold the manual handle 10 and turn it forward quickly to drive the valve rod 7 to rotate 90° counterclockwise, so that the axis of the polished rod mounting hole 6 is perpendicular to the axis of the axial through hole 2. At this time, the limit lever 11 is exactly against the upper side of the lower limit block 13, and the axial through hole 2 is blocked by the outer side of the cylindrical valve core 1 (front side of the cylindrical valve core 1) parallel to the axis of the polished rod mounting hole 6, thereby quickly controlling the blowout.

[0030] During operation, to prevent a blowout from recurring due to misoperation, when the control unit controls the rotary drive unit 8 to operate, the rotary drive unit 8 can only drive the valve stem 7 to rotate 90° counterclockwise and cannot reverse. Therefore, the valve stem 7 can only drive the limit lever 11 to rotate forward and cannot automatically reverse. This invention requires manual release of the cylindrical valve core 1 from the axial through hole 2. That is, during unlocking, the operator can only manually reverse the limit lever 11 until it again abuts against the upper limit block 12, restoring the cylindrical valve core 1 to its original position. This restores the axis of the smooth rod mounting hole 6 and the axis of the axial through hole 2 from a perpendicular state to a coaxial state, opening the wellhead passage and resuming production.

[0031] Depending on the requirements, the manual handle 10 and the valve stem 7 can be connected by a key or spline drive. A handle mounting groove can also be provided on the outside of the valve stem 7 at the location where the manual handle 10 is installed. The cross-section of the valve stem 7 at the handle mounting groove location can be drum-shaped, square, or hexagonal. The shape of the inner side of the mounting ring at the lower end of the manual handle 10 matches the shape of the handle mounting groove, thereby achieving a transmission connection between the manual handle 10 and the valve stem 7. In this embodiment, the manual handle 10 and the valve stem 7 are connected by a square transmission part 25. The upper limit block 12 is located at the 12 o'clock position on the right end face of the valve stem sealing assembly, and the lower limit block 13 is located at the 9 o'clock position on the right end face of the valve stem sealing assembly.

[0032] Example 3: As shown in the attached document Figures 1 to 2 As shown in Figure 4, the valve stem sealing assembly includes a pressure plate 14, a sealing packing 15, and a pressure cap 16. The pressure plate 14, the sealing packing 15, and the pressure cap 16, which are fitted onto the outside of the valve stem 7, are fixedly installed on the inner right side of the valve hole 5 from left to right.

[0033] With this arrangement, the right end face of the pressure plate 14 abuts against the left end face of the sealing packing 15, which can better support the sealing packing 15; the left end face of the pressure cap 16 abuts against the right end face of the sealing packing 15. Rotating the pressure cap 16 in both directions can adjust the tightness between the sealing packing 15 and the valve stem 7 and the valve body 3, ensuring a suitable tightness that can precisely seal the gap between the outer side of the valve stem 7 and the inner right side of the valve hole 5 without affecting the rotation of the valve stem 7 and the cylindrical valve core 1 within the valve hole 5.

[0034] Depending on the requirements, the sealing packing 15 can be an O-ring sealing packing 15, a rubber gasket, or a packing seal ring; the inner side of the right part of the valve hole 5 can be provided with an inner ring groove, the left end face of the pressure plate 14 abuts against the left side wall of the inner ring groove, and the outer side of the pressure cap 16 is connected to the inner side of the right part of the inner ring groove by threads.

[0035] Example 4: As shown in the appendix Figures 1 to 2As shown in Figure 4, the outer side of the right end of the pressure cap 16 is provided with an outer ring platform 17 whose left end abuts against the right end face of the outer protrusion 4. The outer side of the outer ring platform 17 is provided with a first wrench part 18 for easy locking of a wrench. The outer side of the pressure cap 16 corresponding to the left side of the outer ring platform 17 is connected to the inner side of the valve hole 5 by a thread. The outer side of the pressure plate 14 is connected to the inner side of the valve hole 5 by a thread at the corresponding position. The right side of the pressure plate 14 has a number of wrench holes 19 with openings facing to the right evenly distributed along the circumference.

[0036] With this configuration, the outer ring platform 17 can serve as a limiting device. The first wrench part 18 can be a wrench groove or wrench holder with a cross-section that is drum-shaped, square, or hexagonal. In this embodiment, the first wrench part 18 can be a number of openings that are evenly distributed around the circumference of the outer ring platform 17, facing outward and extending through the left and right sides. The wrench suitable for the first wrench part 18 can be a special wrench in the prior art, such as a round nut wrench or a pipe wrench. In this embodiment, there are two wrench holes 19, and the wrench that is suitable for them can be a U-shaped wrench with a handle, such as a U-shaped valve wrench, a U-shaped head wrench, or an F-shaped wrench.

[0037] Example 5: As shown in the attached document Figures 1 to 2 As shown, the rotary drive unit 8 includes a rotary motor and a speed reduction device. The speed reduction device is connected to the outer side of the right end of the valve stem 7. The input end of the speed reduction device is connected to the output end of the rotary motor.

[0038] With this configuration, the speed reduction device can reduce the rotational speed of the rotary motor and effectively increase the torque at the output end of the speed reduction device.

[0039] Depending on the requirements, the speed reduction device in this embodiment can be a speed reducer in the prior art, and the rotary motor can be a servo motor or a stepper motor.

[0040] Example 6: As attached Figure 1 As shown, the valve body 3 has a packing box mounting inner ring groove 20 on the lower inner side, and the upper inner side of the packing box mounting inner ring groove 20 is a lubricating oil storage area 21.

[0041] During use, the inner side of the inner ring groove 20 of the packing box is fixed together with the outer side of the upper part of the sealing packing box by threads. A closed lubricating oil storage space can be formed between the inner side of the inner ring groove 20 of the packing box, the outer side of the polished rod 23 and the upper end face of the sealing packing box. After the lubricating oil is injected into the lubricating oil storage space, it can fully lubricate the outer side of the polished rod 23, effectively improving the service life of the sealing packing in the sealing packing box.

[0042] Example 7: As attached Figures 1 to 2 As shown, the upper outer side of the valve body 3 is provided with a second wrench part 22 for easy locking of a wrench.

[0043] Depending on the requirements, the second wrench part 22 can be a wrench groove or wrench holder with a cross-section that is drum-shaped, square, or hexagonal.

[0044] The above technical features constitute various embodiments of the present invention, which have strong adaptability and implementation effect. Unnecessary technical features can be added or removed according to actual needs to meet the needs of different situations.

Claims

1. A SAGD wellhead dedicated blowout preventer, characterized in that The valve body comprises a cylindrical valve core, a control unit, and a valve body with an axial through-hole in the middle. An outer boss is located on the outer right side of the valve body, and a valve hole opening to the right is located in the middle of the right side of the outer boss. The left end of the valve hole passes through the axial through-hole and stops to the left of the axial through-hole. A cylindrical valve core is fitted inside the left side of the valve hole. A through-hole mounting hole for a smooth rod is located on the cylindrical valve core corresponding to the position of the axial through-hole, and the inner diameter of the through-hole is equal to the inner diameter of the axial through-hole. A valve stem with its right end located to the right of the outer boss is fixedly installed in the middle of the right end face of the cylindrical valve core. A valve stem sealing assembly is fixedly installed between the outer left side of the valve stem and the inner right side of the valve hole. The valve stem sealing assembly can seal the gap between the outer side of the valve stem and the inner right side of the valve hole without affecting the rotation of the valve stem and the cylindrical valve core. A rotary drive unit is connected to the outer right end of the valve stem. The rotary drive unit can drive the cylindrical valve core to rotate 90° through the valve stem, so that the axis of the smooth rod mounting hole is perpendicular to the axis of the axial through hole. A temperature monitoring module that can monitor the valve body temperature in real time is fixedly installed on the outer front part of the valve body. The control unit can collect the valve body temperature in real time. When the valve body temperature exceeds the set threshold, the control unit can automatically control the rotary drive unit to drive the cylindrical valve core of the valve body to rotate 90° and then seal the axial through hole.

2. The SAGD wellhead-only BOP as claimed in claim 1, wherein, A manual rotation assembly is provided on the outer side of the valve stem at the position corresponding to the position between the rotary drive unit and the valve stem sealing assembly, which allows the valve stem to be manually rotated. The manual rotation assembly includes a manual handle, a limit lever, an upper limit block, and a lower limit block. A limit lever is fixedly installed on the upper side of the valve stem at the position corresponding to the right side of the valve stem sealing assembly. A manual handle is connected to the outer side of the valve stem at the position corresponding to the right side of the limit lever. An upper limit block is fixedly installed on the upper right side of the valve stem sealing assembly at the position corresponding to the rear side of the limit lever. A lower limit block is fixedly installed on the front right side of the valve stem sealing assembly, and the included angle between the lower limit block and the upper limit block is 90°. The manual handle can drive the limit lever to rotate between the upper limit blocks through the valve stem.

3. The SAGD wellhead blowout preventer according to claim 1 or 2, characterized in that, The valve stem sealing assembly includes a pressure plate, a sealing packing, and a gland. The pressure plate, sealing packing, and gland, which are fitted onto the outside of the valve stem, are fixedly installed on the inner right side of the valve hole from left to right.

4. The SAGD wellhead-specific blowout preventer according to claim 3, characterized in that, The outer side of the right end of the pressure cap is provided with an outer ring platform whose left end abuts against the right end face of the outer protrusion. The outer side of the outer ring platform is provided with a first wrench part for easy locking of the wrench. The outer side of the pressure cap corresponding to the left side of the outer ring platform is connected to the inner side of the valve hole by a thread. The outer side of the pressure plate is connected to the inner side of the valve hole by a thread at the corresponding position. Several wrench holes with openings to the right are evenly distributed along the circumference on the right side of the pressure plate.

5. The SAGD wellhead blowout preventer according to claim 1, 2, or 4, characterized in that, The rotary drive unit includes a rotary motor and a reduction gear. The reduction gear is connected to the outer side of the right end of the valve stem, and the input end of the reduction gear is connected to the output end of the rotary motor.

6. The SAGD wellhead-specific blowout preventer according to claim 3, characterized in that, The rotary drive unit includes a rotary motor and a reduction gear. The reduction gear is connected to the outer side of the right end of the valve stem, and the input end of the reduction gear is connected to the output end of the rotary motor.

7. The SAGD wellhead blowout preventer according to claim 1, 2, 4, or 6, characterized in that, The valve body has a packing box mounting inner ring groove on the lower inner side, and the upper inner side of the packing box mounting inner ring groove is a lubricating oil storage area.

8. The SAGD wellhead blowout preventer according to claim 3, characterized in that, The valve body has a packing box mounting inner ring groove on the lower inner side, and the upper inner side of the packing box mounting inner ring groove is a lubricating oil storage area.

9. The SAGD wellhead-specific blowout preventer according to claim 5, characterized in that, The valve body has a packing box mounting inner ring groove on the lower inner side, and the upper inner side of the packing box mounting inner ring groove is a lubricating oil storage area.

10. The SAGD wellhead blowout preventer according to any one of claims 1 to 9, characterized in that, The upper outer side of the valve body is provided with a second wrench part for easy locking of the wrench.

Images