Wellhead device damage after the shutdown well temporary plugging device and its construction method

Abstract

The application is a temporary well plugging device after wellhead device is damaged and its construction method, which comprises a reversing seat sealing part, a slip support mechanism and a rubber bowl arranged in a wellbore sealing part; the slip support mechanism connected with the pressure cap outside the central pipe is provided with a slip cone seat and an upper shell with slips, and the slip support mechanism is supported on the upper surface of a support platform in the upper shell through the slip cone seat; a rubber bowl cone with a rubber bowl outside is arranged in the lower shell; the central pipe is threadedly connected with the inner pipe, and the anti-rotation joint is provided with an anti-rotation cavity, and when the wellbore sealing part rotates, the reversing seat sealing part does not rotate. The temporary well plugging can be implemented without wellhead device and pipe column in the well, that is, blowout prevention and kick prevention can be realized, and the wellbore of the closed well can be processed in time, and the blowout accident can be effectively prevented. The wellbore can be quickly sealed without operation equipment, and the application has significant and effective use effect and can produce good economic benefits.

Description

Technical Field

[0001] This invention relates to the field of sealing technology for shut-down wells in the petroleum industry, specifically to a temporary sealing device and construction method for shut-down wells after wellhead equipment damage. Background Technology

[0002] Oil, water, and gas wells that have low production or no exploitation value are generally shut down and not sealed with cement, in order to be reused later.

[0003] Because oil, water, and gas wells are located in the field, during periods of shutdown and abandonment, criminals may attempt to steal wellhead equipment by cutting off the wellhead casing, causing the tubing to fall into the well and resulting in the wellhead becoming uncontrollable. In severe cases, this can lead to a blowout accident.

[0004] According to well control requirements, in such situations, the well must be sealed, wellhead equipment reassembled promptly, and wellhead control devices and measures re-established. Currently, the common method is to inject fluid into the damaged well, reinstall the operating equipment, short-circuit the casing below the packer to seal the wellbore, and seal the tubing in the well with a plug valve. Due to the uncertainty of the wellhead equipment replacement time, when there is sufficient formation pressure, the packer can easily be ejected from the well, causing a well control safety accident.

[0005] To avoid the aforementioned well control safety accidents, a suspended packer is currently used. However, it must be lowered to a certain depth in the well and then set on top of the descending tubing to ensure a seal in the shut-in well and prevent the risk of equipment rising from the well. However, using the suspended packer presents problems such as long tubing tripping time, extended well shut-in operation period, severely impacting operational efficiency, and wasting operational costs.

[0006] In response to the above situation, the current well sealing methods and sealing devices that can be used at the wellhead include the following, for example: Authorization announcement number CN211549633U discloses a multifunctional wellhead anti-theft sealing device, which is used to seal the wellhead. It includes a wellhead assembly with a pressure testing and relief port on the top, a protective pressure cap fastened to the assembly, and a rapid pressure testing and relief component matched with the pressure testing and relief port. This utility model is low in cost and suitable for shut-in wells, newly drilled wells, and wells with overflowing water, providing anti-theft, anti-leakage, and anti-overflow (backflow) functions. It also enables rapid pressure testing and relief of open-hole wells, effectively preventing environmental pollution accidents caused by high bottom pressure leading to outflow, well site water backflow, or external factors.

[0007] The aforementioned utility model can only be installed on the wellhead of a shut-down well, providing some protection, but its safety performance is poor. Once the wellhead device of the shut-down well is damaged, it cannot be installed or used.

[0008] Chinese Patent Application No. 202120186234.5 discloses a mechanical pressure-testing cup seal, comprising a cup seal body, a locking cap fixed to the outer wall of the cup seal body by an internal hexagonal cone-shaped set screw, a cup gasket on the outer wall of the cup seal body, a rubber sealing ring inside the cup gasket, a cup on the outer wall of the cup seal body, a cup on the outer wall of the cup seal body, a cup plug on the left side of the cup on the outer wall of the cup seal body, a movable outer sleeve fitted onto the outer wall of the cup seal body, a fixing block inside the cup seal body, the fixing block being inserted into an internally threaded rod via a pin, the internally threaded rod being connected to the cup seal body, a hanger connected to the left end of the cup seal body, and a lower connector on the right end of the cup seal body. Through the locking cap, pin, and groove, the seal can be achieved not only by the tension of the cup itself, but also by mechanically tensioning the cup to open it and achieve a seal when the seal is ineffective.

[0009] The above-mentioned utility model can achieve a seal by relying on the tension of the diaphragm itself. When the sealing effect is not good, the diaphragm can be opened by mechanical tensioning to achieve a sealing effect. This type of diaphragm seal has a single purpose and can only be used for wellhead pressure testing. It cannot solve the problems of suspension, blowout prevention, and top-out prevention of the tubing string in the well during shutdown.

[0010] Chinese Patent Application No. 202111218162.9 discloses a suspended pressure testing tool and method for blowout preventers (BOPs), including a cup packer; it also includes a suspension body and a cup packer center body; the cup packer is fitted onto the outer wall of the cup packer center body, and the cup packer is located below the suspension body; the upper end of the cup packer center body is suspended on the suspension body, and the suspension body has an axially through pressure transmission channel. This invention allows the test pressure and the weight of the tubing to act entirely on the suspension, effectively changing the stress on the tubing during BOP testing, improving construction safety, and increasing the success rate and accuracy of BOP testing.

[0011] The tool in the above invention has a solid structure. During the pressure test, the pressure does not act inside the tubing. The tension generated by the inner cup of the tubing annulus is transferred to the hanger, so that the pressure test pressure and the weight of the tubing string all act on the hanger. This solves the problems of low pressure bearing capacity and easy damage to the casing of the current slip-type pressure testing tool. It has a better sealing effect at the wellhead, but it cannot fundamentally solve the problems of blowout prevention and top-out prevention in shut-in wells.

[0012] Therefore, there is an urgent need to develop a device that can be operated without the need for onboard equipment, to temporarily seal and shut down the casing or wellbore, so as to allow sufficient time for the subsequent safe installation of wellhead equipment. Summary of the Invention

[0013] To address the aforementioned deficiencies in existing technologies, the purpose of this invention is to provide a temporary sealing device and construction method for shut-down wells after wellhead equipment damage. This device allows for the rapid temporary sealing of the wellbore of shut-down wells without the need to reinstall operating equipment, thereby improving operational efficiency, reducing operating costs, effectively preventing blowout accidents in shut-down wells within a short period, and creating ample time for subsequent installation of wellhead equipment and establishment of wellhead control measures.

[0014] The technical solution of this invention is: a temporary sealing device for shut-down wells after wellhead equipment damage, comprising a reversing seat, wherein: a slip support mechanism and a cup are provided in the wellbore sealing part; the slip support mechanism, connected to the outside of the central tube by a pressure cap, has a slip cone seat and an upper shell with slips, and the slip support mechanism is supported on a support platform in the upper shell by the slip cone seat; a cup cone with a cup sleeve is installed in the upper shell below the support platform; the upper joint connected to the tubing sub is connected from top to bottom to the central tube with the slip cone seat threadedly connected, the inner tube with the cup cone threadedly connected, and the lower joint of the inner tube, and is connected to the anti-rotation joint, the track center tube with a reversing track in the reversing seat, and the lower joint through the lower joint of the inner tube; the central tube is threadedly connected to the inner tube, and the anti-rotation joint has an anti-rotation cavity, so that when the wellbore sealing part rotates, the reversing seat does not rotate.

[0015] Preferably, the tubing sub is connected to the upper connector, the central tube, the inner tube, and the lower connector of the inner tube by threads; the connecting thread between the central tube and the inner tube is a coarse thread.

[0016] Preferably, the slip is installed in a slip groove in the upper housing, a slip seat is installed in the upper housing above the slip groove, and a slip cone is installed between the upper housing below the slip and the slip cone seat; the slip and slip groove in the upper housing are arranged in three or more sets.

[0017] Preferably, the upper outer side of the slip is provided with an I-shaped stop block that matches the groove structure of the upper part of the slip groove; the upper end of the slip is provided with an upper inclined surface that is lower in the inside and higher in the outside, which matches the lower inclined surface that is higher in the inside and lower in the outside of the slip seat and is pressed into the upper shell by the lower inclined surface of the slip seat; the slip seat is a cylindrical body and the lower part of the cylindrical body is a downwardly inclined conical surface.

[0018] Preferably, the slip cone is a cylindrical body and has slip guide grooves in the upper outer conical surface, which are equal in number to the number of slips and correspond to the lower inclined surface of the slips, so that the slips can extend and retract along the slip guide grooves; the tips of the slip teeth on the outer wall of the slips point downwards.

[0019] Preferably, the slip cone seat has a non-uniform outer diameter with the lower outer diameter larger than the upper outer diameter, and the slip cone is mounted on the lower outer diameter step of the slip cone seat; the inner diameter of the slip cone seat is provided with an internal thread that connects to the central pipe thread; a spacer ring is also installed between the support platform and the slip cone seat, and a sealing ring is installed on the outer diameter of the spacer ring.

[0020] Preferably, the cup cone is a cylindrical body with a non-uniform outer diameter. The upper inner circle of the cup cone is provided with an internal thread that connects to the internal pipe thread. The upper outer circle of the cup cone is provided with a sealing ring, and two or more longitudinal anti-rotation grooves are provided below the sealing ring. Anti-rotation locking pins installed from the upper housing can be inserted into the anti-rotation grooves. The lower end of the upper outer circle of the cup cone cooperates with the inner circle limiting step at the lower end of the upper housing.

[0021] Preferably, the small outer diameter section between the upper outer circle and the lower conical outer circle of the cup cone is smaller than the inner diameter of the inner circle limiting step at the lower end of the upper shell. The cup is installed outside the small outer diameter section of the cup cone and located below the upper shell. The lower conical outer circle of the cup cone is a downwardly sloping conical outer circle that matches the upwardly sloping conical inner circle of the cup.

[0022] Preferably, the lower outer circle of the pressure cap is threaded to the upper shell and the inner circle is provided with a sealing ring, and the central tube can pass through the pressure cap and be threaded to the upper connector; an upper connector locking pin is also installed between the threaded connection section of the upper connector and the central tube.

[0023] Preferably, the anti-rotation cavity in the anti-rotation joint is located between the threaded sections of the upper inner circle and the lower inner circle. The inner diameter of the anti-rotation cavity is larger than the lower outer diameter of the lower inner tube joint, allowing the lower inner tube joint to rotate within the anti-rotation cavity. The threaded section of the lower inner circle of the anti-rotation joint is threadedly connected to the center tube of the track.

[0024] Preferably, the lower outer circle of the inner tube connector is larger than the upper outer circle and is a blind tube with the lower end sealed. The inner circle of the inner tube connector is threaded to the inner tube and a bearing is installed between the lower outer circle and the anti-rotation cavity of the anti-rotation connector. The upper end of the oil pipe stub can also be connected to a plug valve.

[0025] The construction method for a temporary plugging device for shut-down wells after damage to the aforementioned wellhead equipment includes the following steps: A. Connecting a plug valve to the upper end of the tubing sub; B. Lifting the temporary plugging device using hoisting equipment; C. Raising the tubing sub to seat the reversing and setting portion in the wellbore; D. Rotating the tubing sub on the surface to lower the central pipe connected to the tubing sub; E. After the casing is sealed, closing the plug valve.

[0026] Preferably, when the temporary sealing device is unsealed inside the casing, the oil pipe section is rotated in the opposite direction on the ground. After the support slip and the cup are retracted, the oil pipe section is pressed down, causing the reversing and straightening mechanism in the reversing seat to enter the short track, thus unsealing the anchor.

[0027] Compared with the prior art, the significant advantages of the present invention are as follows: The present invention is mainly applied to shut-down wells where the wellhead device is damaged, such as shut-down wells where the casing is cut short or the wellhead is damaged. It can temporarily seal the well without the wellhead device and without the tubing string in the well, which can prevent both blowout and top-out, facilitate timely treatment of the wellbore of the shut-down well, and effectively prevent the occurrence of blowout accidents. The specific effects of the device of the present invention are as follows: (1) The present invention suspends the temporary sealing device in the wellbore near the wellhead. The device is first fixed in the well by utilizing the function of the reversing and sealing part. The device is lifted up so that the reversing and straightening mechanism in the reversing and sealing part moves from the short track to the long track, pushes the anchor fixing mechanism upward, and hangs the anchor on the inner wall of the casing to prevent the device from falling.

[0028] (2) The cup cone in the well casing sealing part of this device is used to expand the cup and expand the sealing sleeve to achieve sealing of the shut-off well.

[0029] (3) Rotating the tubing stub on the ground will cause the central tube and inner tube connected to the tubing stub to rotate together, causing the slip cone and the cup cone, which are threadedly connected to the central tube and inner tube, to rotate simultaneously, so that the slip is locked in the inner wall of the casing and the cup seals the casing. The operation is simple and effective.

[0030] (4) In this invention, the slips in the well casing sealing part are reverse slips with the tips of the slip teeth facing downwards, which provides better clamping force on the casing and prevents the reversing seat part in the device located below and the downhole tools connected to it from being pushed up. After the cup expands, it sticks tightly to the inner wall of the casing and can prevent the fluid in the well from rising under a certain pressure.

[0031] The device of this invention changes the existing technology that requires upper-level equipment to be lowered into the packer to seal the wellhead when temporarily sealing the wellbore, which results in long construction time and high operating costs.

[0032] This invention enables rapid sealing of the wellbore after a casing short-joint is cut during well shutdown, without requiring additional work equipment. Simply rotating the tubing short section on the surface allows the reverse-positioned slips to engage within the casing wall, preventing internal components connected to the device from being pushed up. Because the pressure inside the shut-off well is very low, it effectively prevents blowouts in a short period, allowing ample time for the subsequent implementation of wellhead safety and anti-theft measures.

[0033] This invention features safe and reliable operation, as well as sealing and anti-overhead protection, effectively improving the well control safety factor after a shut-in well is damaged. Because it can quickly seal the wellbore without requiring any work equipment, it significantly reduces operating costs, demonstrating significant and effective results and generating good economic benefits. Attached Figure Description

[0034] The accompanying drawings are provided to further illustrate the invention and form part of the specification. They are used in conjunction with embodiments of the invention to explain the invention and do not constitute a limitation thereof. In the drawings: Figure 1 This is a schematic diagram of the structure of the present invention; Figure 2 yes Figure 1 A partially enlarged structural diagram of the upper and middle joints and the slip support mechanism; Figure 3 yes Figure 1 A partially enlarged structural diagram of the middle and conical parts of the leather bowl; Figure 4 yes Figure 1 A partially enlarged schematic diagram of the anchor tile fixing mechanism; Figure 5 yes Figure 1 A partially enlarged schematic diagram of the reversing and straightening mechanism.

[0035] In the diagram: 1. Upper connector; 2. Upper connector locking pin; 3. Pressure cap; 4. Central tube; 5. Upper shell; 6. Slip seat; 7. Slip; 8. Slip groove; 9. Slip cone; 10. Slip cone seat; 11. Spacer ring; 12. Support platform; 13. Inner tube; 14. Anti-rotation locking pin; 15. Anti-rotation groove; 16. Leather cup; 17. Leather cup cone; 18. Anti-rotation connector; 19. Limit sleeve; 20. Anchor cone; 21. Anchor; 22. Anchor seat; 23. Spring; 24. Lower shell; 25. Locking short connector; 26. Straightening block sleeve; 27. Support spring; 28. Straightening block; 29. ​​Slip ring; 30. Track center tube; 31. Lower connector; 32. Reversing track; 33. Inner tube lower connector; 34. Bearing. Detailed Implementation

[0036] The accompanying drawings are for reference and illustration only and are not intended to limit the scope of protection of this invention. The technical solutions of the embodiments of this invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this invention without creative effort are within the scope of protection of this invention.

[0037] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0038] In the description of this invention, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings and are only for the convenience of describing the 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, and therefore should not be construed as a limitation of the invention. Furthermore, in the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0039] See Figures 1-5 A temporary sealing device for shut-down wells after wellhead equipment damage includes a reversing sealing section, wherein: a slip support mechanism and a cup 16 are installed in the wellbore sealing section; the slip support mechanism, connected to the outside of the central pipe 4 via a pressure cap 3, has a slip cone seat 10 and an upper housing 5 fitted with slips 7; the slip support mechanism is supported on a support platform 12 in the upper housing 5 via the slip cone seat 10; a cup cone 17 with a cup 16 fitted on its lower outer side is installed in the upper housing 5 below the support platform 12; and with The upper connector 1 of the tubing short section is connected from top to bottom to the central tube 4, which is threaded to the slip cone seat 10, the inner tube 13, which is threaded to the cup cone 17, and the lower connector 33 of the inner tube. The lower connector 33 of the inner tube is connected to the anti-rotation connector 18, the track center tube 30, which has a reversing track 32 in the reversing seat part, and the lower connector 31. The central tube 4 is threaded to the inner tube 13, and the anti-rotation connector 18 has an anti-rotation cavity. When the wellbore sealing part rotates, the reversing seat part does not rotate.

[0040] The reversing seat section in the device of this invention uses the reversing seat section of the commonly used 211 packer. This reversing seat section includes a limiting sleeve 19, an anchor cone 20, an anchor 21, an anchor seat 22, a booster spring 23, a lower outer shell 24, a locking short connector 25, a straightening block sleeve 26, a support spring 27, a straightening block 28, a slip ring 29, a track center tube 30, a lower connector 31, and a reversing track 32. The limiting sleeve 19, anchor cone 20, anchor 21, anchor seat 22, spring 23, lower outer shell 24, and locking short connector 25 constitute the anchor fixing mechanism; the straightening block sleeve 26, support spring 27, straightening block 28, slip ring 29, and track center tube 30 constitute the reversing straightening mechanism.

[0041] Both the anchor fixing mechanism and the reversing and straightening mechanism are installed outside the track center tube 30. The reversing track 32 is formed by connecting a long track and a short track machined on the outer wall of the track center tube 30. When the track center tube 30 in the reversing seat is lifted, the reversing and straightening mechanism installed on its outside is moved into the long track, and at the same time, it pushes the anchor fixing mechanism installed above upward to move it upward. Under the action of the assist spring 23, the anchor seat 22 and the thrust of the reversing and straightening mechanism, the anchor 21 in the anchor fixing mechanism is pushed outward along the slope of the anchor cone 20 and fixed in the well barrel or casing.

[0042] When it is discovered that the wellhead device related to the well stoppage has been damaged, the device of the present invention is lowered into the wellbore through the tubing short section. Pulling up the tubing short section at the wellhead can fix the reversing seat part in the casing, thus completing the fixation of the device in the casing.

[0043] Then, the tubing sub and center tube 4 are rotated downwards at the wellhead. As the slip cone seat 10, which is threaded to the center tube 4, is compacted and supported on the support platform 12 in the upper shell 5, the slip cone seat 10 moves upward relative to the center tube 4 under the action of the support platform 12, pushing the slip 7 outwards and supporting it in the wellbore. At the same time, the inner tube 13, which is threaded to the center tube 4, is threaded to the cup cone 17. The cup cone 17 rotates upward relative to the inner tube 13, expanding the cup 16 and sealing the wellbore.

[0044] The device of this invention is simple to operate. After the reversing seat part located at the lower part of the device is fixed in the wellbore, rotating the tubing short section at the wellhead will cause the central tube 4 to drive the inner tube 13 to rotate in the anti-rotation joint 18. Because the anti-rotation joint 18 has an anti-rotation cavity, the lower reversing seat part does not rotate, while only the upper central tube 4 and inner tube 13 rotate relative to each other, allowing the slip 7 to extend from the upper shell 5 and support itself in the wellbore, while simultaneously causing the cup cone 17 to open the cup 16 and seal the wellbore. This device is used for temporary sealing of shut-in wells after the wellhead device is damaged, allowing sufficient time for subsequent installation of wellhead devices and establishment of security and anti-theft measures on the shut-in wells, including oil wells, water injection wells, and gas wells.

[0045] Based on the above embodiment one, the present invention also has the following embodiments: In a preferred embodiment, the tubing sub is threadedly connected to the upper connector 1, the central tube 4, the inner tube 13, and the lower connector 33 of the inner tube; the thread connecting the central tube 4 and the inner tube 13 is a coarse thread. This allows for rapid rotation between the two components, resulting in a quick seal of the wellbore.

[0046] In a preferred embodiment: the slip 7 is installed in the slip groove 8 in the upper housing 5, the upper housing 5 above the slip groove 8 is equipped with a slip seat 6, and the upper housing 5 below the slip 7 is equipped with a slip cone 9 between the slip cone seat 10 and the slip 7; the slip 7 and slip groove 8 in the upper housing 5 are arranged in three or more sets.

[0047] In a preferred embodiment: the upper outer side of the slip 7 is provided with an I-shaped stop block that cooperates with the groove structure of the upper part of the slip groove 8; the upper end of the slip 7 is provided with an upper inclined surface that is lower in the inside and higher in the outside, which cooperates with the lower inclined surface that is higher in the inside and lower in the outside of the slip seat 6 and is pressed into the upper shell 5 by the lower inclined surface of the slip seat 6; the slip seat 6 is a cylindrical body and the lower part of the cylindrical body is a downwardly inclined conical surface.

[0048] In a preferred embodiment: the slip cone 9 is a cylindrical body with slip guide grooves in its upper outer conical surface, the number of which is equal to that of the slips 7 and corresponds to the lower inclined surface of the slips 7, allowing the slips 7 to extend and retract along the slip guide grooves; the tips of the slip teeth on the outer wall of the slips 7 point downwards. Pointing the tips of the slip teeth downwards provides better anti-overturning effect and higher pressure resistance. Conventionally used slips have their inclined surfaces located at the upper part of the slip body, while the inclined surfaces of the slips 7 in this device are located at the lower part of the slip body, making them reverse slips.

[0049] In a preferred embodiment: the slip cone seat 10 has a non-uniform outer diameter with the lower outer diameter larger than the upper outer diameter; the slip cone 9 is mounted on the lower outer diameter step of the slip cone seat 10; the inner diameter of the slip cone seat 10 is threaded to connect with the central tube 4; a spacer ring 11 is also installed between the support platform 12 and the slip cone seat 10, and a sealing ring is installed on the outer diameter of the spacer ring 11. Installing the spacer ring 11 here can shorten the machining length or machining height of the lower part of the slip cone seat 10, reducing the machining difficulty of the slip cone seat 10. If the spacer ring 11 is not used, the sealing ring is installed in the lower outer diameter of the slip cone seat 10.

[0050] In a preferred embodiment: the cup cone 17 is a cylindrical body with a non-uniform outer diameter. The upper inner circle of the cup cone 17 has an internal thread that connects to the inner tube 13. The upper outer circle of the cup cone 17 has a sealing ring, and two or more longitudinal anti-rotation grooves 15 are provided below the sealing ring. Anti-rotation locking pins 14 inserted from the upper housing 5 can be inserted into the anti-rotation grooves 15. The lower end of the upper outer circle of the cup cone 17 mates with the inner circle limiting step at the lower end of the upper housing 5. By providing longitudinal anti-rotation grooves 15 and inserting anti-rotation locking pins 14 into the upper outer circle of the cup cone 17, the cup cone 17 cannot rotate circumferentially when the inner tube 13 rotates; it can only move up and down. This reduces wear between the cup cone 17 and the cup 16 during rotation and improves the sealing effect of the cup 16.

[0051] In a preferred embodiment: the small outer diameter section between the upper outer circle and the lower conical outer circle of the cup cone 17 is smaller than the inner diameter of the inner circle limiting step at the lower end of the upper shell 5. The cup 16 is installed outside the small outer diameter section of the cup cone 17 and located below the upper shell 5. The small outer diameter section of the cup cone 17 allows the cup cone 17 to slide up and down in the upper shell 5, causing the cup 16 to expand and retract. The lower conical outer circle of the cup cone 17 is a downwardly sloping conical outer circle that matches the upwardly sloping conical inner circle of the cup 16.

[0052] In a preferred embodiment: the lower outer circle of the pressure cap 3 is threaded to the upper housing 5 and the inner circle is provided with a sealing ring; the central tube 4 can pass through the pressure cap 3 and be threaded to the upper connector 1; an upper connector locking pin 2 is also installed between the threaded connection section of the upper connector 1 and the central tube 4 to increase its connection strength.

[0053] In a preferred embodiment: the anti-rotation cavity in the anti-rotation joint 18 is located between the threaded sections of the upper inner circle and the lower inner circle. The inner diameter of the anti-rotation cavity is larger than the lower outer diameter of the inner tube lower joint 33, and the inner tube lower joint 33 can rotate in the anti-rotation cavity; the threaded section of the lower inner circle of the anti-rotation joint 18 is threadedly connected to the track center tube 30.

[0054] In a preferred embodiment: the lower outer circle of the inner tube lower connector 33 is larger than the upper outer circle and is a blind pipe with a sealed lower end; the inner circle of the inner tube lower connector 33 is threaded to the inner tube 13, and a bearing 34 is installed between the lower outer circle and the anti-rotation cavity of the anti-rotation connector 18, which makes the pipe string formed by the tubing short section, upper connector 1, central tube 4 and inner tube 13 in the wellbore sealing part of this device rotate more smoothly; the upper end of the tubing short section can also be connected to a plug valve to ensure construction safety and prevent oil and gas from rising in the well; the lower connector 31 can be connected to the tubing in the well or the tools or plugs in the well.

[0055] The construction method for a temporary plugging device for a shut-in well after the wellhead device has been damaged includes the following steps: A. Connecting a plug valve to the upper end of a tubing sub; B. Lifting the temporary plugging device using hoisting equipment; and then slowly placing the device into the wellbore of the shut-in well after the wellhead device has been damaged. The hoisting equipment can be a lifting clamp, a chain hoist, or a small crane.

[0056] C. Raise the tubing section to set the reversing sealing part in the wellbore; during this process, the reversing and straightening mechanism, which was originally located in the short track of the reversing track 32, enters the long track; at the same time, the straightening block sleeve 26 in the reversing and straightening mechanism pushes the locking section 25 in the anchor fixing mechanism and the lower housing 24 equipped with the anchor seat 22 and the assist spring 25 upward, clamping the anchor 21 in the well casing, thereby fixing the device of the present invention in the well.

[0057] D. Rotate the tubing sub on the surface to lower the central tube 4 connected to it. During this process, as the slips 7 are secured inside the casing, the cup 16 simultaneously expands to seal the casing. Rotating the tubing sub causes the connected upper connector 1, central tube 4, and inner tube 13 to rotate simultaneously. Under the action of the support platform 12, the central tube 4 moves downward along the inner tube 13. Because the slip cone seat 10 is threadedly connected to the central tube 4 and moves upward relative to it, it can drive the slip cone 9 upward and push out the slips 7, supporting them inside the casing. The slips 7 have downward-facing teeth and are reverse slips, which can firmly fix them inside the casing. At the same time, the inner tube 13 moves upward relative to the central tube 4. Because the cup cone 17 is threadedly connected to the inner tube 13 and moves upward along with it, the cup 16 expands to seal the casing, preventing the fluid in the well from rising. The slips 7 can also prevent the well components connected to this device below from rising.

[0058] E. After the casing is sealed, close the plug valve. At this point, the next steps for installing the wellhead equipment and implementing wellhead rectification measures can be arranged.

[0059] In a preferred embodiment: when the temporary sealing device is unsealed inside the casing, the oil pipe section is rotated in the opposite direction on the ground. After the support slip 7 and the cup 16 are retracted, the oil pipe section is lifted, causing the reversing and straightening mechanism in the reversing seat to descend, and the anchor 21 is retracted to unseal.

[0060] The embodiments described above are merely typical examples, but the present invention is not limited to these embodiments. Those skilled in the art can make modifications without departing from the spirit and teachings of the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the inventive spirit and concept of the present invention should be included within the protection scope of the present invention. Therefore, the protection scope is not limited to the above description.

Claims

1. A temporary sealing device for shut-down wells after wellhead equipment damage, including a reversing sealing section, characterized in that, A slip support mechanism and a cup (16) are installed in the wellbore sealing section; the slip support mechanism, which is connected to the outside of the central pipe (4) by a pressure cap (3), has a slip cone seat (10) and an upper shell (5) fitted with slips (7). The slip support mechanism is supported on the support platform (12) in the upper shell (5) by the slip cone seat (10); the upper shell (5) below the support platform (12) is fitted with a cup cone (17) with a cup (16) fitted on its lower outer side; the upper connector (1) connected to the tubing sub is installed from top to bottom. The central tube (4) is connected to the slip cone seat (10) by a thread, the inner tube (13) is connected to the cup cone (17) by a thread, and the lower connector (33) of the inner tube is connected to the anti-rotation connector (18) and the central tube (30) of the reversing seat seal part which is provided with a reversing track (32) and the lower connector (31). The central tube (4) is threaded to the inner tube (13), and the anti-rotation connector (18) is provided with an anti-rotation cavity. When the wellbore sealing part rotates, the reversing seat seal part does not rotate.

2. The temporary sealing device for shut-down wells after wellhead equipment damage as described in claim 1, characterized in that, The oil pipe sub-section is connected to the upper connector (1), the central pipe (4), the inner pipe (13), and the lower connector (33) of the inner pipe by threads; the connecting thread between the central pipe (4) and the inner pipe (13) is a coarse thread.

3. The temporary sealing device for shut-down wells after wellhead device damage as described in claim 2, characterized in that, The slip (7) is installed in the slip groove (8) in the upper housing (5). A slip seat (6) is installed in the upper housing (5) above the slip groove (8). A slip cone (9) is installed between the upper housing (5) below the slip (7) and the slip cone seat (10). There are three or more sets of slips (7) and slip grooves (8) in the upper housing (5).

4. The temporary sealing device for shut-down wells after wellhead device damage as described in claim 3, characterized in that, The upper outer side of the slip (7) is provided with an I-shaped stop block that matches the groove structure on the upper part of the slip groove (8). The upper end of the slip (7) is provided with an upper inclined surface that is lower in the inside and higher in the outside, which matches the lower inclined surface that is higher in the inside and lower in the outside of the slip seat (6) and is pressed into the upper shell (5) by the lower inclined surface of the slip seat (6). The slip seat (6) is a cylindrical body and the lower part of the cylindrical body is a downwardly inclined conical surface.

5. The temporary sealing device for shut-down wells after wellhead device damage as described in claim 4, characterized in that, The slip cone (9) is a cylindrical body and has slip guide grooves in the upper outer conical surface that are equal in number to the slips (7) and correspond to the lower inclined surface of the slips (7), which allow the slips (7) to extend and retract along the slip guide grooves; the tips of the slip teeth on the outer wall of the slips (7) point downwards.

6. The temporary sealing device for shut-down wells after wellhead device damage as described in claim 5, characterized in that, The slip cone seat (10) has a non-uniform outer diameter and the lower outer diameter is larger than the upper outer diameter. The slip cone (9) is installed on the lower outer diameter step of the slip cone seat (10). The inner diameter of the slip cone seat (10) is provided with an internal thread that is threaded to the central tube (4). A spacer ring (11) is also installed between the support platform (12) and the slip cone seat (10), and a sealing ring is installed on the outer diameter of the spacer ring (11).

7. The temporary sealing device for shut-down wells after wellhead equipment damage as described in claim 2, characterized in that, The cup cone (17) is a cylindrical body with an outer circle that is not of equal diameter. The upper inner circle of the cup cone (17) is provided with an internal thread that is threaded to the inner tube (13). The upper outer circle of the cup cone (17) is provided with a sealing ring and two or more longitudinal anti-rotation grooves (15) are provided at the lower part of the sealing ring. Anti-rotation locking pins (14) installed from the upper shell (5) can be inserted into the anti-rotation grooves (15). The lower end of the upper outer circle of the cup cone (17) is matched with the inner circle limiting step at the lower end of the upper shell (5).

8. The temporary sealing device for shut-down wells after wellhead equipment damage as described in claim 7, characterized in that, The small outer diameter section between the upper outer circle and the lower conical outer circle of the cup cone (17) is smaller than the inner diameter of the inner circle limiting step at the lower end of the upper shell (5). The cup (16) is installed outside the small outer diameter section of the cup cone (17) and located below the upper shell (5). The lower conical outer circle of the cup cone (17) is a downwardly sloping conical outer circle and matches the upwardly sloping conical inner circle of the cup (16).

9. The temporary sealing device for shut-down wells after wellhead device damage as described in claim 2, characterized in that, The lower outer circle of the pressure cap (3) is threaded to the upper shell (5) and the inner circle is provided with a sealing ring. The central tube (4) can pass through the pressure cap (3) and be threaded to the upper connector (1). An upper connector locking pin (2) is also installed between the threaded connection section of the upper connector (1) and the central tube (4).

10. The temporary sealing device for shut-down wells after wellhead device damage as described in claim 2, characterized in that, The anti-rotation cavity in the anti-rotation joint (18) is located between the threaded sections of the upper inner circle and the lower inner circle. The inner diameter of the anti-rotation cavity is larger than the lower outer diameter of the inner tube lower joint (33), and the inner tube lower joint (33) can rotate in the anti-rotation cavity. The threaded section of the lower inner circle of the anti-rotation joint (18) is threadedly connected to the track center tube (30).

11. The temporary sealing device for shut-down wells after wellhead equipment damage as described in claim 10, characterized in that, The lower outer circle of the inner tube lower connector (33) is larger than the upper outer circle and is a blind pipe with the lower end blocked. The inner circle of the inner tube lower connector (33) is threaded to the inner tube (13) and a bearing (34) is installed between the lower outer circle and the anti-rotation cavity of the anti-rotation connector (18). The upper end of the oil pipe short section can also be connected to the plug valve.

12. A construction method for a temporary sealing device for shut-down wells after damage to the wellhead equipment as described in any one of claims 1-11, characterized in that, The steps include: A. Connecting a plug valve to the upper end of the tubing sub; B. Lifting a temporary sealing device using hoisting equipment; C. Raising the tubing sub to set the reversing sealing part in the wellbore; D. Rotating the tubing sub on the ground to lower the central pipe (4) connected to the tubing sub; E. After the casing is sealed, closing the plug valve.

13. The construction method of the temporary sealing device for shut-down wells after wellhead device damage as described in claim 12, characterized in that, When the temporary sealing device is unsealed inside the casing, the oil pipe short section is rotated in the opposite direction on the ground. After the support slip (7) and the cup (16) are retracted, the oil pipe short section is pressed down, so that the reversing and straightening mechanism in the reversing seat seal part enters the short track, allowing the anchor tile (21) to be unsealed.

Images