Multi-functional well pack-off device

Abstract

The present application belongs to the technical field of oilfield production equipment, and particularly relates to a multifunctional well sealing device, which comprises a packing dynamic sealing structure, a well sealing structure and an axial radial concentric adjusting structure; the packing box structure comprises an upper end pressure body, a large cavity cylinder, a blowout prevention seat, a guide sleeve and a pre-tightening spring, and the upper end pressure body, the large cavity cylinder and the small cavity cylinder are sequentially threadedly connected; the well sealing structure comprises a rotating ring pressure cover, a rotating ring, an outer connecting cylinder, a connecting cylinder lower pressure body, an upper blocking ring, a lower blocking ring and a connecting hub, the outer connecting cylinder is threadedly connected with the small cavity cylinder, and the connecting hub is threadedly connected with the outer connecting cylinder; the axial radial concentric adjusting structure comprises a ball connecting body, a ball seat pressure cover, an adjusting ball seat, a tubing head seat and an adjusting disc pressure cover, the ball connecting body is threadedly connected with the connecting hub, and the adjusting disc pressure cover is threadedly connected with the tubing head seat after being sleeved on the adjusting ball seat. All the loss sealing elements can be replaced under pressure, the packing part of the added packing does not need tools, and the radial and axial directions can be concentrically adjusted.

Description

Technical Field

[0001] This invention belongs to the field of oilfield production equipment technology, specifically relating to a multifunctional well sealing device. Background Technology

[0002] The pumping units used in current oilfield production connect the polished rod to the wellhead via a donkey-head suspension rope, causing it to move up and down and drive the downhole pump to draw downhole fluids. A reciprocating dynamic seal is formed between the polished rod and the Christmas tree. This reciprocating dynamic seal is generally achieved by two devices: the polished rod dynamic seal packing box and the Christmas tree polished rod sealer. During daily production, rubber, graphite packing, or other sealing materials are filled into the polished rod dynamic seal packing box to form a reciprocating dynamic seal with the polished rod. The sealing packing in the packing box is periodically worn by the reciprocating motion of the polished rod, requiring manual pre-tightening and replacement. When replacing, the lower Christmas tree sealer must be closed to prevent pressurized fluid from spraying out of the well, and then auxiliary tools are used to remove the sealing packing from the packing box for replacement. The existing well sealing devices have the following defects: 1. When the sealing packing in the packing box is worn, the well sealer can be shut off to seal the well fluid and replace it. However, when the sealing components in the well sealer are damaged, there is no switch at the bottom, so the well fluid cannot be sealed again. Furthermore, the structure of the well sealer cannot be repaired and replaced separately in the case of no-wash kill. It can only be replaced by unloading the pumping unit load after the well is washed and killed, and then inserting a brand new well sealer through the polished rod. This process requires about three special vehicles, 24m³ of hot water, and about 5 workers, and takes 2-4 hours. It is time-consuming, labor-intensive, and costly, and may also cause well fluid leakage and environmental pollution. 2. The sealing material in the packing box needs to be replaced frequently and requires auxiliary tools, which is labor-intensive. The existing structure of the sealing material has a jamming point and cannot be self-tightened by the well pressure. 3. There are radial and axial eccentricity problems in the installation of the wellhead Christmas tree and the polished rod. Summary of the Invention

[0003] To address the aforementioned technical problems, this invention provides a multifunctional well sealing device. This device is used to seal the polished rod at the wellhead of the pumping unit during daily production. All wear-resistant seals within the device can be replaced under pressure without cleaning or well-killing. The packing material for the packing section requires no tools, and both radial and axial adjustments are possible.

[0004] The technical solution adopted in this invention is: a multifunctional well sealing device, including a packing dynamic sealing structure, a well sealing structure, and an axial-radial concentric adjustment structure;

[0005] The packing box structure includes an upper pressure body, a large cavity, a blowout preventer, a guide sleeve, and a preload spring; the pressure body, the large cavity, and the small cavity are connected by threads in sequence, and the first sealing cavity formed by the large cavity and the second sealing cavity formed by the small cavity are both filled with rubber seals. The guide sleeve is installed at the bottom of the small cavity, the preload spring is placed inside the guide sleeve, and the blowout preventer is installed above the guide sleeve.

[0006] The well sealing structure includes a rotating ring cap, a rotating ring, an outer connecting cylinder, a lower pressure body of the connecting cylinder, an upper retaining ring, a lower retaining ring, and a connecting hub. The upper part of the outer connecting cylinder is threadedly connected to the bottom of the small cavity cylinder. The upper retaining ring is threadedly installed above the inner part of the outer connecting cylinder below the guide sleeve. The lower retaining ring is threadedly installed on the top of the connecting hub, and the upper and lower retaining rings form a third sealing cavity. The upper part of the connecting hub is threadedly connected to the lower part of the outer connecting cylinder. The rotating ring is fitted over the raised edge of the outer connecting cylinder and threadedly connected to the outer connecting cylinder. The rotating ring cover of the connection is axially limited, and a fourth sealing groove is opened on the rotating ring; the lower pressure body of the connecting cylinder is threadedly connected to the bottom of the outer connecting cylinder; both the rotating ring and the outer connecting cylinder are provided with pressurized packing holes with the same hole position; a first sealing groove is opened around the pressurized packing hole on the outer connecting cylinder; a second sealing groove is opened on the convex edge of the outer connecting cylinder; after the lower part of the outer connecting cylinder is connected to the connecting hub, a third sealing groove is formed with the outer wall of the connecting hub (the seal is formed after assembly with the connecting hub); sealing elements are provided in the first sealing groove, the second sealing groove, the third sealing groove and the fourth sealing groove;

[0007] The axial-radial concentric adjustment structure includes a ball connector, a ball seat cover, an adjusting ball seat, an oil pipe head seat, and an adjusting disc cover. The bottom end of the adjusting ball seat is provided with a horizontal adjusting disc. The upper part of the ball connector is threadedly connected to the lower part of the connecting pivot. The ball head at the bottom of the ball connector rests on the spherical seat of the adjusting ball seat and is fastened by the ball seat cover threadedly connected to the upper part of the adjusting ball seat. The adjusting disc cover is fitted onto the lower part of the adjusting ball seat and threadedly connected to the upper part of the oil pipe head seat. The horizontal adjusting disc at the bottom end of the adjusting ball seat sits on the top of the oil pipe head seat.

[0008] Furthermore, the outer diameter of the first sealing cavity of the large cavity is larger than the outer diameter of the second sealing cavity of the small cavity.

[0009] Furthermore, the threaded connection between the outer connecting cylinder and the small cavity cylinder is replaced by welding.

[0010] Furthermore, the lower retaining ring is replaced by being fixed to the top of the connecting hub by welding, instead of being threaded onto the top of the connecting hub.

[0011] Furthermore, the threaded connection between the upper part of the ball connector and the lower part of the connecting hub is replaced by welding.

[0012] Furthermore, the rotating ring is replaced by a ball valve or a gate valve, which is installed on the pressurized packing hole of the outer connecting cylinder via a threaded connection.

[0013] The beneficial effects of this invention are as follows: This invention provides a multifunctional well sealing device. This well sealing device is used for sealing the polished rod at the wellhead of the pumping unit during daily production in oil wells. All worn seals within the device can be replaced under pressure, and it also possesses multiple sealing functions. Replacing and maintaining the sealing packing in the well sealing section does not require well flushing or unloading; adding packing to the packing section requires no tools; and both radial and axial adjustments are concentric. Attached Figure Description

[0014] Figure 1 This is a schematic diagram of the main structure of the multifunctional well sealing device in Embodiment 1;

[0015] Figure 2 This is a cross-sectional structural diagram of the multifunctional well sealing device in Embodiment 1;

[0016] Figure 3 yes Figure 2 A magnified view of part I;

[0017] Figure 4 This is a schematic diagram of the main structure of the outer connecting cylinder in Embodiment 1;

[0018] Figure 5 This is a cross-sectional structural diagram of the outer connecting cylinder in Embodiment 1. Detailed Implementation Example

[0019] Referring to the figures, a multifunctional well sealing device includes a packing dynamic sealing structure, a well sealing structure, and an axial-radial concentric adjustment structure;

[0020] The packing box structure includes an upper pressure body 1, a large cavity cylinder 2, a blowout preventer 5, a guide sleeve 6, and a preload spring 7; the pressure body, the large cavity cylinder, and the small cavity cylinder are connected by threads in sequence, and the first sealing cavity 21 formed by the large cavity cylinder and the second sealing cavity 22 formed by the small cavity cylinder are both filled with rubber seals, the guide sleeve is installed at the bottom of the small cavity cylinder, the preload spring is placed inside the guide sleeve, and the blowout preventer is installed above the guide sleeve;

[0021] The well sealing structure includes a rotating ring cap 4, a rotating ring 8, an outer connecting cylinder 9, a connecting cylinder lower pressure body 10, an upper retaining ring 12, a lower retaining ring 19, and a connecting hub 16. The upper part of the outer connecting cylinder is threadedly connected to the bottom of the small cavity cylinder. The upper retaining ring is threadedly installed above the inner part of the outer connecting cylinder below the guide sleeve. The lower retaining ring is threadedly installed on the top of the connecting hub. The upper and lower retaining rings form a third sealing cavity 23. The upper part of the connecting hub is connected to the lower part of the outer connecting cylinder by an internal thread. The rotating ring is fitted above the convex edge of the outer connecting cylinder and is threadedly connected to the outer connecting cylinder. The rotating ring cover of the threaded connection is axially limited, and a fourth sealing groove 81 is opened on the rotating ring; the lower pressure body of the connecting cylinder is threadedly connected to the bottom of the outer connecting cylinder; both the rotating ring and the outer connecting cylinder are provided with pressure packing holes 20 with the same hole position; a first sealing groove 91 is opened around the pressure packing hole on the outer connecting cylinder; a second sealing groove 92 is opened on the convex edge of the outer connecting cylinder; after the lower part of the outer connecting cylinder is connected to the connecting hub, a third sealing groove 101 is formed with the outer wall of the connecting hub (a seal formed after assembly with the connecting hub); sealing elements are provided in the first sealing groove, the second sealing groove, the third sealing groove and the fourth sealing groove;

[0022] The axial-radial concentric adjustment structure includes a ball connector 11, a ball seat cap 13, an adjusting ball seat 14, an oil pipe head seat 15, and an adjusting disc cap 17. The bottom end of the adjusting ball seat is provided with a horizontal adjusting disc 18. The upper part of the ball connector is threadedly connected to the lower part of the connecting pivot. The ball head at the bottom of the ball connector rests on the spherical seat of the adjusting ball seat and is fastened by the ball seat cap threadedly connected to the upper part of the adjusting ball seat. The adjusting disc cap is fitted onto the lower part of the adjusting ball seat and threadedly connected to the upper part of the oil pipe head seat. The horizontal adjusting disc at the bottom end of the adjusting ball seat sits on the top of the oil pipe head seat. The outer diameter of the first sealing cavity of the large cavity is larger than the outer diameter of the second sealing cavity of the small cavity.

[0023] The blowout preventer (BOP) and guide sleeve in the packing box section can move up and down within the small chamber. During use, a sealing rubber component is inserted into the first sealing cavity in the large chamber, and the connecting thread between the large and small chambers is rotated. The thread force automatically presses the sealing rubber component into the second sealing cavity in the small chamber, compressing it to create a seal. This simplifies the process of using specialized tools to compress and hammer the sealing rubber component into the small cavity, a process previously required in existing technologies. The BOP is an inverted cone shape, resting on the guide sleeve and preload spring. During use, the well pressure and the preload force generated by the spring act together and continuously on the bottom of the BOP, constantly compressing the sealing packing in the small chamber. This compensates for wear on the sealing packing in the small chamber, achieving a significant extension of the preload time through self-tightening by utilizing well pressure.

[0024] Both the rotating ring and the outer connecting cylinder are equipped with pressurized packing holes. A cylindrical sealing groove (first sealing groove) is formed around the pressurized packing hole of the outer connecting cylinder. A second sealing groove is formed on the raised edge of the outer connecting cylinder. The outer connecting cylinder, after being assembled with the connecting hub, forms a third sealing groove. A fourth sealing groove is formed on the upper end face of the rotating ring. All four sealing grooves are external seals. When the seals in the four sealing grooves age or are damaged, rotating the outer connecting cylinder reduces the size of the third sealing cavity and squeezes the sealing packing inside, thus sealing the well fluid before replacement. When the packing in the third sealing cavity ages or is damaged, rotating the rotating ring aligns its pressurized packing hole with the pressurized packing hole on the outer connecting cylinder, and an external pressurized packing gun is used to add the packing. If both are damaged simultaneously, under conditions of slight external leakage, the packing is first added to the third sealing cavity using the external pressurized packing gun, and then the outer connecting cylinder is rotated to create a seal. This switching and replacement method solves the technical problem of replacing and maintaining the sealing packing of the well sealing section without washing, well killing, or unloading. All sealing packing can be replaced under pressure.

[0025] The current solid, monolithic rubber component of the polished rod seal in the well-sealing section is replaced with dispersed granular rubber. This breaks down the solid rubber into smaller, dispersed granules, which are then pressurized and added into the corresponding polished rod sealing space (the third sealing chamber) of the well-sealing device. This third sealing chamber is a variable space; as its volume decreases, all the granular rubber is compressed to create a seal. All other sealing structures in the well-sealing configuration are external seals, and the sealing packing can be replaced by closing the third sealing chamber of the well-sealing device. This allows for pressurized addition of sealant to damaged polished rod seals and for replacement of damaged seals in other parts of the well-sealing configuration by closing the well-sealing device. This switching and replacement mechanism enables maintenance of the well-sealing components without the need for well flushing or killing.

[0026] The ball head at the lower part of the ball connector of the axial-radial concentric adjustment section rests in the spherical seat at the upper part of the adjusting ball seat and is secured by the ball seat cover, enabling axial angle adjustment within a certain range. A horizontal adjusting disc is located at the bottom of the adjusting ball seat and rests on the tubing head seat. The inner diameter of the adjusting disc cover's port is larger than the outer diameter of the horizontal adjusting disc, allowing the horizontal adjusting disc to move horizontally a certain distance after assembly, thus achieving horizontal adjustment. Axial angle adjustment can be achieved through the combination of the ball connector, ball seat cover, and adjusting ball seat; horizontal adjustment can be achieved through the combination of the adjusting ball seat, tubing head seat, and adjusting disc cover; and consequently, concentric adjustment of both radial and axial directions can be realized. Example

[0027] The threaded connection between the outer connecting cylinder and the small cavity cylinder is replaced by welding; the lower retaining ring, which is threadedly installed on the top of the connecting hub, is replaced by welding to the top of the connecting hub; the threaded connection between the upper part of the ball connector and the lower part of the connecting hub is replaced by welding. The rotating ring and the first sealing groove on the cylindrical surface constitute a cylindrical surface seal. Alternatively, the rotating ring and the cylindrical surface sealing groove can be omitted, and an internal through valve (such as a ball valve or gate valve) can be used, with the switch connected by threads or welding to the pressurized packing hole to replace the switching function formed by the rotating ring and the cylindrical surface sealing groove.

[0028] The multi-functional well sealing device adopts a brand-new structural design based on the design concept that any internal rubber seal can be replaced under pressure. This structure changes the original wellhead sealing device's leakage points. Any leakage point can be maintained under pressure by switching. It integrates the functions of polished rod dynamic seal packing box, wellhead sealing device, and concentricity adjustment device into one unit. It achieves many advantages such as self-compensation of dynamic seal wear using well pressure, tool-free replacement of polished rod dynamic seal packing, no need for well flushing and unloading for well sealing part seal maintenance, concentric anti-wear adjustment, and multiple functions.

Claims

1. A multifunctional well sealing device, characterized in that: The multi-functional well sealing device includes a packing dynamic seal structure, a well sealing structure, and a radial concentric adjustment structure; The packing box structure includes an upper pressure body, a large cavity, a blowout preventer, a guide sleeve, and a preload spring; the pressure body, the large cavity, and the small cavity are connected by threads in sequence, and the first sealing cavity formed by the large cavity and the second sealing cavity formed by the small cavity are both filled with rubber seals. The guide sleeve is installed at the bottom of the small cavity, the preload spring is placed inside the guide sleeve, and the blowout preventer is installed above the guide sleeve. The well-sealing structure includes a rotating ring cap, a rotating ring, an outer connecting cylinder, a lower pressure body of the connecting cylinder, an upper retaining ring, a lower retaining ring, and a connecting hub. The upper part of the outer connecting cylinder is threadedly connected to the bottom of the small cavity cylinder. The upper retaining ring is threadedly installed on the outer connecting cylinder below the guide sleeve. The lower retaining ring is threadedly installed on the top of the connecting hub, and the upper and lower retaining rings form a third sealing cavity. The upper part of the connecting hub is threadedly connected to the outer connecting cylinder. The rotating ring is fitted over the convex edge of the outer connecting cylinder and... A rotating ring cap threadedly connected to the outer connecting cylinder provides axial positioning, and a fourth sealing groove is provided on the rotating ring; the lower pressure body of the connecting cylinder is threadedly connected to the bottom of the outer connecting cylinder; both the rotating ring and the outer connecting cylinder are provided with pressurized packing holes with the same hole position, a first sealing groove is provided around the pressurized packing hole on the outer connecting cylinder, a second sealing groove is provided on the convex edge of the outer connecting cylinder, and the lower part of the outer connecting cylinder forms a third sealing groove with the outer wall of the connecting hub; sealing elements are provided in the first, second, third, and fourth sealing grooves; The axial-radial concentric adjustment structure includes a ball connector, a ball seat cover, an adjusting ball seat, an oil pipe head seat, and an adjusting disc cover. The bottom end of the adjusting ball seat is provided with a horizontal adjusting disc. The upper part of the ball connector is threadedly connected to the lower part of the connecting hub. The ball head at the bottom of the ball connector rests on the spherical seat of the adjusting ball seat and is fastened by the ball seat cover threadedly connected to the upper part of the adjusting ball seat. The adjusting disc cover is fitted onto the lower part of the adjusting ball seat and threadedly connected to the upper part of the oil pipe head seat. The horizontal adjusting disc at the bottom end of the adjusting ball seat sits on the top of the oil pipe head seat.

2. The multifunctional well sealing device according to claim 1, characterized in that: The outer diameter of the first sealing cavity of the large cavity is larger than the outer diameter of the second sealing cavity of the small cavity.

3. The multifunctional well sealing device according to claim 1, characterized in that: The threaded connection between the outer connecting cylinder and the small cavity cylinder is replaced by welding.

4. The multifunctional well sealing device according to claim 1, characterized in that: The lower retaining ring, which was originally installed on the top of the connecting hub by threads, is now fixed to the top of the connecting hub by welding.

5. The multifunctional well sealing device according to claim 1, characterized in that: The threaded connection between the upper part of the ball connector and the lower part of the connecting hub is replaced by welding.

6. The multifunctional well sealing device according to claim 1, characterized in that: The rotating ring is replaced by a ball valve or gate valve, which is installed on the pressurized packing hole of the outer connecting cylinder via a threaded connection.

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