An oil well polished rod seal and its packing ring

Abstract

The utility model discloses an oil well polished rod seal strip and its sealing packing, the sealing strip body in which is the spiral strip body of two end closed and inside longitudinal reinforcing rib and airtight cavity, the pressure -bearing medium is installed in airtight cavity, the appearance structure of sealing strip body is in accord with the internal structure of polished rod seal box to be loaded after disc stack. The sealing packing in which, the packing center hole of sealing packing after spiral stacking, discing of sealing strip body is less than the external diameter of polished rod and the appearance is in accord with the internal structure of polished rod seal box to be loaded. Using the utility model can realize the compression of wellhead polished rod seal box and polished rod simultaneously, and its sealing effect is remarkable, guarantees wellhead seal box not to seep, not to leak. Effectively avoid the occurrence and all bad consequences brought by oil leakage, seepage and other conditions at wellhead polished rod seal box, remarkably reduce production cost, reduce the daily management workload of staff.

Description

Technical Field

[0001] This utility model relates to a sealing component in the polished rod sealing box of an oil well in oil and gas development, specifically an oil well polished rod sealing strip and its sealing packing. Background Technology

[0002] In the oil well production process, most oil wells use reciprocating pumping units, such as beam pumping units, chain pumping units, and high-altitude belt pumping units.

[0003] When a reciprocating pumping unit is operating, the polished rod connects the suspension cable to the sucker rod string, driving the pump piston inside the well to reciprocate and pump well fluid to the surface. In oil wells using this type of reciprocating pumping unit, sealing the polished rod at the wellhead is a common challenge.

[0004] Traditional sealing boxes use metal clamps to compress the packing, and the packing used is all hard-core packing. When sealing the polished rod, the tightening cap of the packing presses downwards, causing the packing to deform and expand, thus sealing the polished rod. However, this type of packing has insufficient radial expansion, and often only the uppermost packing layer bears the force, while the lower packing layers only play a supporting role. This results in uneven stress on the packing, leading to poor sealing performance of the packing on the polished rod. This easily causes oil leakage and seepage from the polished rod sealing box, resulting in unclean production sites and environmental pollution. In addition to increasing the daily maintenance workload of oil production workers, it also requires frequent well shutdowns to replace the packing, affecting normal oil well production and increasing oil production costs.

[0005] To address the aforementioned issues, production site managers and technicians have undertaken numerous tasks, and a search has revealed the following related patented technologies.

[0006] Patent application number CN20201037350.0 discloses a smooth rod sealing packing, comprising multiple main body portions stacked and coaxially arranged. Each main body portion is annular and has a through hole through which a smooth rod can pass, allowing the main body portion to be fitted onto the smooth rod. The interior of each main body portion has a deformation space to enable deformation capability. The cross-section of each main body portion is rectangular, and the edges of the inner and / or outer annular surfaces of each main body portion are provided with beveled surfaces. When two adjacent main body portions are stacked, the two beveled surfaces of the two main body portions that are close to each other are aligned and form an oil guide groove between them.

[0007] However, the packing described above still has the following drawbacks: the packing is composed of multiple separate parts, which makes it inconvenient to install and carry; gaps at the joints of the parts can easily cause poor sealing; and the hollow part is not sealed and cannot conduct pressure.

[0008] Patent application number CN201320301705.8 discloses a composite sealing packing for the polished rod of an oil well, comprising: an upper elastic body, a fiber rope, and a lower elastic body; the upper and lower elastic bodies of the composite sealing packing for the polished rod of the oil well are both elongated strip structures, and the cross-sections of the upper and lower elastic bodies are both rectangular structures with a semi-circular hole in the middle. The upper and lower elastic bodies cooperate to form a rectangular cross-section, and a fiber rope is provided in the middle circular hole. Several semi-circular through holes are evenly distributed on the sides of the upper and lower elastic bodies in a radial direction perpendicular to the semi-circular hole, and the upper and lower elastic bodies cooperate to form oil holes.

[0009] However, the aforementioned packings are mainly composite packings, which still have the following drawbacks: their internal structure is complex, making them difficult to process; although their lubrication is good, the packing deformation is insufficient, resulting in a less than ideal sealing effect.

[0010] Patent application CN201510067317.1 discloses a serrated packing sealing device, comprising a rubber body that is elongated and has a circular cross-section with serrated edges. Multiple nylon threads are embedded longitudinally and parallel within the rubber body. The packing of this invention is elongated and has a serrated cross-section. This device has been used in oil wells, and field tests have shown significant results, extending the packing's service life by three times, reducing polished rod wear by 30%, reducing worker workload, improving work efficiency, and ensuring the smooth progress of crude oil extraction. The packing of this invention is elongated and has a serrated cross-section. This device has been used in oil wells, and field tests in over 1000 pumping wells have shown significant results, extending the packing's service life by three times.

[0011] The aforementioned invention improves the shape of the packing and has a better performance. However, although the serrated edges of the packing can further seal after compression, the serrations wear down after a period of use, and the anti-leakage effect of the serrated edges will decrease. There is still room for further improvement in wellhead sealing packing.

[0012] In summary, although there are various types of packing currently available, most of them are hard core packings, and they generally suffer from unsatisfactory sealing strips and sealing effects, and still need improvement. Summary of the Invention

[0013] To address the shortcomings of current packing systems, this paper proposes a new oil well polished rod sealing strip and its sealing packing. This new strip offers improved compression and expansion properties, allowing the stacked sealing strips to achieve simultaneous axial and radial compression, more even stress distribution, and better overall integrity, resulting in superior sealing performance. This prevents oil leakage and seepage at the wellhead polished rod sealing box and avoids all related adverse consequences, thereby reducing production costs and the workload of daily management personnel.

[0014] The technical solution of this utility model is: an oil well polished rod sealing strip, wherein: the sealing strip body is a spiral strip-shaped body with closed ends and longitudinally reinforced ribs and a sealed cavity inside; the sealed cavity is filled with a pressure-bearing medium; the external structure of the sealing strip body, after being stacked, conforms to the internal structure of the polished rod sealing box to be installed.

[0015] Preferably, the pressure-bearing medium is hydraulic oil.

[0016] Preferably, the pressure-bearing medium is water.

[0017] Preferably, the pressure-bearing medium is air.

[0018] Preferably, the sealing strip body is made of nitrile rubber, the inner diameter of the sealed cavity is set between 5mm and 8mm, and the reinforcing rib is nylon thread.

[0019] Preferably, the sealing strip body is made of fluororubber; the inner diameter of the sealed cavity is set between 5mm and 8mm; and the reinforcing rib is nylon thread.

[0020] Preferably, the sealing strip body is made of polyurethane rubber; the inner diameter of the sealed cavity is set between 5mm and 8mm; and the reinforcing rib is nylon thread.

[0021] A sealing packing, wherein: a sealing strip body is provided, and the sealing packing after the sealing strip body is spirally stacked and coiled has a central hole smaller than the outer diameter of the smooth rod and its shape matches the internal structure of the smooth rod sealing box to be installed.

[0022] Preferably, the angle between the overlapping spiral lines formed between the spirally stacked and coiled sealing strip bodies and the radial parallel lines of the sealing packing is set between 25 and 35 degrees.

[0023] Preferably, the angle between the overlapping spiral lines formed between the sealing strip bodies and the radial parallel lines of the sealing packing is 30 degrees.

[0024] Compared with the prior art, the significant effect of this utility model is that the sealing strip in this utility model has a soft core structure with a pressure-bearing medium installed in a closed cavity, which gives it excellent compression and expansion performance. The sealing packing formed by stacking it can achieve simultaneous compression in the axial and radial directions.

[0025] This invention utilizes the incompressibility of liquids and gases to increase the overall expandability of the sealing packing, thereby enhancing the sealing effect. When the sealing packing is pressed downwards, the liquid or gas in the sealed cavity is also compressed, causing the sealed cavity to expand outwards as a whole, resulting in the sealing packing expanding inwards and outwards. This simultaneously achieves the compression of the wellhead polished rod sealing box and the polished rod, resulting in a significant sealing effect and ensuring that the wellhead sealing box is leak-proof. It effectively avoids oil leakage, seepage, and other adverse consequences at the wellhead polished rod sealing box, significantly reducing production costs and the daily management workload of employees.

[0026] The sealing packing formed by coiling the spiral-shaped sealing strip has excellent overall performance and is consistent with the internal structure of the polished rod sealing box into which it is installed. The sealing packing made from the coiled sealing strip has a simple structure, making installation and replacement in the wellhead polished rod sealing box convenient and quick, and the operation is simple and practical. When installing into the polished rod sealing box, it can be inserted simply from the top of the polished rod; when it is damaged and needs replacement, it can be simply pulled out of the polished rod sealing box, significantly reducing the workload of packing replacement and lowering the labor intensity and daily management workload for employees.

[0027] Compared to ordinary packing, which only expands at its uppermost end, resulting in insufficient radial expansion within the entire polished rod seal box and thus poor sealing, this invention addresses the issue of ordinary packing having a smaller compression deformation. Ordinary packing requires greater force to achieve a seal and has a shorter effective lifespan, necessitating frequent tightening. However, when ordinary packing is used in heavy oil production wells, applying excessive force to compress the packing within the polished rod seal box can easily lead to an overly tight fit between the packing and the polished rod, causing the polished rod to slowly descend. This slow descent can easily result in production accidents in the oil well.

[0028] The sealing strip in this invention has a soft core structure, making it easier to expand to both sides, thus achieving a better sealing effect with less force. When applied to heavy oil production wells, it prevents the polished rod from slowly descending, effectively avoiding production accidents and generating significant economic benefits. While ensuring safe production, it significantly reduces the daily maintenance workload and labor intensity for employees handling the polished rod sealing box.

[0029] Using this invention reduces the probability of wellhead oil leakage, thereby reducing environmental pollution and well control risks caused by wellhead oil leakage, while also reducing related costs, increasing well operating rates, and increasing economic benefits.

[0030] In conclusion, this utility model has significant practical effects and can bring good economic benefits, and has great application and promotion value. Attached Figure Description

[0031] The accompanying drawings are provided to further illustrate the present invention and form part of the specification. They are used together with the embodiments of the present invention to explain the present invention, but do not constitute a limitation thereof. In the drawings: Figure 1 This is a cross-sectional view of the sealing packing structure after the sealing strip is coiled and placed in the conical inner cavity of the smooth rod sealing box.

[0032] Figure 2 yes Figure 1 A schematic diagram of its external structure.

[0033] Figure 3 This is a schematic diagram of the external structure of the sealing packing after the sealing strip is coiled and placed in the cylindrical inner cavity of the smooth rod sealing box.

[0034] In the diagram: 1. Sealing strip body; 2. Overlapping spiral line; 3. Sealed cavity; 4. Packing center hole; 5. Reinforcing rib. Detailed Implementation

[0035] The accompanying drawings are for reference and illustration only and are not intended to limit the scope of protection of this utility model. The technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.

[0036] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model 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 of the present utility model and are not intended to limit the present utility model.

[0037] In the description of this utility model, it should be understood that the terms "length," "width," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," and "outer," etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing this utility model 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 this utility model. Furthermore, in the description of this utility model, "a plurality of" means two or more, unless otherwise explicitly specified.

[0038] See Figure 1 - Figure 3A sealing strip for oil well polished rods, wherein: the sealing strip body 1 is a spiral strip-shaped body with both ends closed and longitudinally reinforced with ribs 5 and a sealed cavity 3 inside; the sealed cavity 3 is filled with a pressurized medium; the external structure of the sealing strip body 1, after being stacked, conforms to the internal structure of the polished rod sealing box to be installed.

[0039] The sealing strip in this invention is not rigid but flexible, and is a flexible spiral strip formed by filling a pressurized medium into a sealed cavity 3 in the sealing strip body 1.

[0040] In this invention, the sealed cavity 3 is filled with a pressurized medium. Utilizing the incompressibility of the pressurized medium, the sealing strip body 1 automatically expands to both sides during the adjustment and pressing of the smooth rod sealing box, effectively sealing the gap between the sealing strip body 1 and the inner cavity of the smooth rod sealing box, as well as the gap between the sealing strip body 1 and the smooth rod.

[0041] The sealing strip in this invention can be manufactured according to the internal structure of the bare rod sealing box to be installed. That is, the external dimensions and shape of the sealing strip body 1 match the internal structure of the bare rod sealing box after being coiled. This ensures that the spiral strip's natural spiral shape matches the internal structure of the bare rod sealing box, forming a good seal.

[0042] The sealing strip body 1 of this utility model is reinforced with reinforcing ribs 5, which can further increase the overall strength of the sealing strip body 1.

[0043] Based on the above embodiment one, the present invention also has the following embodiments: a preferred embodiment: the pressure-bearing medium is hydraulic oil.

[0044] In a preferred embodiment, the pressure-bearing medium is water.

[0045] In a preferred embodiment, the pressure-bearing medium is air.

[0046] In a preferred embodiment: the sealing strip body 1 is made of nitrile rubber, the inner diameter of the sealed cavity 3 is set between 5mm and 8mm, and the reinforcing rib 5 is nylon thread.

[0047] In a preferred embodiment: the sealing strip body 1 is made of fluororubber; the inner diameter of the sealed cavity 3 is set between 5mm and 8mm; and the reinforcing rib 5 is nylon thread.

[0048] In a preferred embodiment: the sealing strip body 1 is made of polyurethane rubber; the inner diameter of the sealed cavity 3 is set between 5mm and 8mm; and the reinforcing rib 5 is nylon thread.

[0049] See Figure 2 and Figure 3Sealing packing: It is provided with a sealing strip body 1. The sealing packing center hole 4 of the sealing packing after the sealing strip body 1 is spirally stacked and coiled is smaller than the outer diameter of the smooth rod and its shape matches the internal structure of the smooth rod sealing box to be installed.

[0050] If the inner cavity of the inserted bare rod sealing box is a straight cylindrical cavity, the thickness of the outer wall of the sealing strip body 1 is consistent from top to bottom, except that it is cut at the inner sides of the top and bottom ends to conform to the horizontal end face. The spiral stacked and coiled shape is a straight cylindrical shape that matches the straight cylindrical inner cavity of the bare rod sealing box. See [link to documentation]. Figure 3 .

[0051] If the inner cavity of the inserted bare rod sealing box is conical, then use a sealing strip body 1 with a lower outer wall thickness smaller than the upper outer wall thickness, and adjust both ends to make the coiled shape conical. Figure 1 and Figure 2 The sealing packing shown is the structure and shape of the sealing strip body 1 after being spirally stacked and coiled in the smooth rod sealing box inserted into the conical inner cavity.

[0052] In a preferred embodiment, the angle between the overlapping spiral lines 2 formed between the spirally stacked and coiled sealing strip bodies 1 and the radial parallel line of the sealing packing is set between 25 and 35 degrees. This ensures that the sealing packing placed in the smooth rod sealing box has good pressure-bearing performance and outward expansion performance.

[0053] In a preferred embodiment, the angle between the overlapping spiral lines 2 formed between the sealing strip bodies 1 and the radial parallel lines of the sealing packing is 30 degrees. This results in better pressure-bearing performance and outward expansion performance.

[0054] The spiral structure of the sealing strip body 1, after coiling, results in a sealing packing with good overall performance and is consistent with the internal structure of the smooth rod sealing box into which it is installed. The sealing packing constructed using a spiral sealing strip has a simple structure, and its installation and replacement in the wellhead smooth rod sealing box are convenient and quick, making it simple and practical to operate.

[0055] When installing the sealing packing into the smooth rod sealing box, the sealing packing can be inserted from the top of the smooth rod; when the sealing packing is damaged and needs to be replaced, it can be pulled out from the smooth rod sealing box.

[0056] 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 sealing strip for the polished rod of an oil well, characterized in that, The sealing strip body is a spiral strip-shaped body with closed ends and longitudinal reinforcing ribs and a sealed cavity inside; the sealed cavity is filled with a pressurized medium; the external structure of the sealing strip body, after being stacked, matches the internal structure of the bare rod sealing box to be installed.

2. The oil well polished rod sealing strip as described in claim 1, characterized in that, The pressure-bearing medium is hydraulic oil.

3. The oil well polished rod sealing strip as described in claim 1, characterized in that, The pressure-bearing medium is water.

4. The oil well polished rod sealing strip as described in claim 1, characterized in that, The pressure-bearing medium is air.

5. The oil well polished rod sealing strip as described in claim 1, characterized in that, The sealing strip body is made of nitrile rubber, the inner diameter of the sealed cavity is set between 5mm and 8mm, and the reinforcing rib is made of nylon thread.

6. The oil well polished rod sealing strip as described in claim 1, characterized in that, The sealing strip body is made of fluororubber; the inner diameter of the sealed cavity is set between 5mm and 8mm; the reinforcing rib is nylon thread.

7. The oil well polished rod sealing strip as described in claim 1, characterized in that, The sealing strip body is made of polyurethane rubber; the inner diameter of the sealed cavity is set between 5mm and 8mm; the reinforcing rib is nylon thread.

8. Sealing packing, characterized in that, It is equipped with a sealing strip body. The sealing packing after the sealing strip body is spirally stacked and coiled has a central hole smaller than the outer diameter of the smooth rod and its shape matches the internal structure of the smooth rod sealing box to be installed.

9. The sealing packing as described in claim 8, characterized in that, The angle between the overlapping spiral lines formed between the spirally stacked and coiled sealing strip bodies and the radial parallel lines of the sealing packing is set between 25 and 35 degrees.

10. The sealing packing as claimed in claim 9, characterized in that, The angle between the overlapping spiral lines formed between the sealing strip bodies and the radial parallel lines of the sealing packing is 30 degrees.

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