A drill pipe threaded joint
By setting a groove area and a smooth surface area on the sealing bevel of the drill pipe threaded joint, the sealing reliability problem caused by metal debris and grease is solved, and effective sealing and assembly accuracy are achieved under high pressure conditions.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- SHANGHAI HILONG DRILL PIPE CO LTD
- Filing Date
- 2026-04-17
- Publication Date
- 2026-07-31
AI Technical Summary
During use, existing drill pipe threaded joints cannot effectively contain and release metal debris, excess grease, and trapped air, resulting in reduced sealing reliability, especially prone to leakage under high temperature and high pressure conditions downhole.
A grooved area and a smooth area are provided on the sealing bevel of the drill pipe threaded joint. The grooved area is used to accommodate metal shavings and excess grease, while the smooth area is used to maintain the seal. The groove is spirally arranged along the sealing bevel and gradually narrows. The angle between the sidewall of the groove and the bottom surface is 80° to 85°. The ratio of groove depth to width is 0.1 to 1. The area of the grooved area accounts for 10% to 50%, and the projected length of the smooth area is 20% to 70%.
It effectively contains and guides metal shavings and grease, improves sealing reliability, ensures precise assembly torque, enhances sealing performance, prevents wear and leakage, and improves anti-loosening effect.
Smart Images
Figure CN122061689B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of drilling tools, and in particular to a drill pipe threaded joint. Background Technology
[0002] Drill pipe threaded joints play a crucial role in oil and gas extraction, geological exploration, and other engineering fields, transmitting torque and tensile / compressive loads and maintaining drill string sealing. During on-site assembly and actual use of drill pipe joints, repeated engagement and friction of the threaded pair, as well as unavoidable installation errors, often result in metal debris being generated at the thread crest, root, and sealing cone surface. Meanwhile, to ensure lubrication of the threaded pair and prevent seizing, special thread grease is usually applied during assembly. However, thread grease can easily accumulate locally during tightening and may trap air, creating tiny gaps that are difficult to expel.
[0003] If these metal debris, excess grease, and trapped air cannot be effectively contained and channeled, they will directly affect the integrity of the metal-to-metal contact sealing surface. On the one hand, hard debris may embed in the sealing surface, causing scratches or point-like leakage channels; on the other hand, grease and air may form a non-uniform medium layer under high-pressure conditions, reducing the uniformity of contact stress distribution and weakening the actual specific pressure of the sealing strip. This can lead to leakage of drilling fluid or high-pressure gas at the joint under high-temperature and high-pressure conditions downhole, resulting in reduced sealing reliability.
[0004] Therefore, there is a need for a drill pipe threaded joint structure that can effectively accommodate and properly channel metal shavings, excess grease, and trapped air generated during assembly and use, thereby improving sealing reliability. Summary of the Invention
[0005] The purpose of this invention is to provide a drill pipe threaded joint that solves the technical problem of low joint sealing reliability caused by metal debris, grease and air in the prior art.
[0006] In a first aspect, embodiments of the present invention provide a drill pipe threaded connector, comprising: a male connector and a female connector, the male connector comprising a threaded base section, an external thread section, a receiving cavity surface, a sealing bevel surface, and a cylindrical surface extending sequentially; the female connector comprising a threaded boring section, an internal thread section, a receiving cavity surface, a sealing bevel surface, and a cylindrical surface extending sequentially; the external thread and the internal thread engage with each other; the receiving cavity surface of the male connector does not contact the receiving cavity surface of the female connector and forms a receiving cavity; the sealing bevel surface of the male connector contacts the sealing bevel surface of the female connector. There is a gap between the cylindrical surface of the male connector and the cylindrical surface of the female connector; the sealing slope of the male connector or the sealing slope of the female connector includes a groove area and a smooth area along the axial direction, the groove area is located on the side of the sealing slope near the receiving cavity surface, the smooth area is located on the side of the sealing slope near the cylindrical surface, the groove area includes a plurality of grooves, the area of the plurality of grooves accounts for 10% to 50% of the area of the groove area, and the axial projection length of the smooth area is 20% to 70% of the axial projection length of the sealing slope.
[0007] Furthermore, the groove is spirally arranged along the sealing slope, and the spiral direction of the groove is the same as the spiral direction of the thread.
[0008] Furthermore, the groove gradually narrows along the direction in which its spiral diameter decreases.
[0009] Furthermore, the groove is discontinuous in its helical direction.
[0010] Furthermore, the included angle between the sidewall and the bottom surface of the groove is 80°~85°.
[0011] Furthermore, the hardness of the sidewalls and bottom surface of the groove is greater than the hardness of the other parts of the sealing slope excluding the groove.
[0012] Furthermore, the groove is subjected to laser hardening.
[0013] Furthermore, the ratio of the depth to the width of the groove ranges from 0.1 to 1.
[0014] Furthermore, the roughness of the sealing bevel, excluding the groove, is less than 1.6 μm.
[0015] Furthermore, the roughness of the smooth area is less than the roughness of the other parts of the groove area excluding the groove.
[0016] The embodiments of the present invention have at least the following technical effects:
[0017] This invention provides a drill pipe threaded connector with a cavity between the threaded section and the sealing bevel for accommodating grease, air, and metal debris. During high-pressure operation, to prevent metal debris from damaging the sealing bevel and reducing sealing reliability, a groove is provided on a portion of the sealing bevel near the cavity surface to actively collect and accommodate metal debris, reducing the possibility of friction between the sealing bevels. This groove design also facilitates the collection of excess grease and air from the cavity during assembly, resulting in more precise torque during assembly. The area of the groove accounts for 10% to 50% of the total area of the groove region, and the axial projection length of the smooth surface area is 20% to 70% of the axial projection length of the sealing bevel. This design ensures both the collection of metal debris and the accommodation of grease and air while maintaining a tight seal, thus improving overall sealing reliability. Attached Figure Description
[0018] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.
[0019] Figure 1 This is a schematic cross-sectional view of a drill pipe threaded joint provided in an embodiment of the present invention;
[0020] Figure 2 This is a schematic diagram of the first type of external sealing inclined surface structure provided in an embodiment of the present invention;
[0021] Figure 3 This is a schematic diagram of the second type of external sealing inclined surface structure provided in an embodiment of the present invention;
[0022] Figure 4 This is a schematic cross-sectional view of the groove provided in an embodiment of the present invention.
[0023] Icons: 1-Male connector; 2-Female connector; 3-Receiving cavity; 11-Outer main shoulder surface; 12-Thread base section; 13-External thread section; 14-Outer receiving cavity surface; 15-Outer sealing bevel; 16-Outer cylindrical surface; 17-Outer end face; 21-Inner main shoulder surface; 22-Thread boring section; 23-Internal thread section; 24-Inner receiving cavity surface; 25-Inner sealing bevel; 26-Inner cylindrical surface; 27-Inner end face; 151-Groove area; 152-Smooth surface area; 1511-Groove; 15111-Groove sidewall; 15112-Groove bottom surface. Detailed Implementation
[0024] The technical solution of the present invention will be clearly and completely described below with reference to the embodiments. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.
[0025] It will be understood by those skilled in the art that, unless otherwise defined, all terms used herein (including technical and scientific terms) have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. It should also be understood that terms such as those defined in general dictionaries should be understood to have the same meaning as in the context of the prior art, and should not be interpreted in an idealized or overly formal sense unless specifically defined as herein.
[0026] Those skilled in the art will understand that, unless specifically stated otherwise, the singular forms “a,” “an,” “the,” and “the” used herein may also include the plural forms. It should be further understood that the term “comprising” as used in this specification means the presence of the stated features, integers, steps, operations, elements, and / or components, but does not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and / or combinations thereof. The term “and / or” as used herein includes all or any units and all combinations of one or more associated listed items.
[0027] For the first aspect, please refer to Figure 1 and Figure 2 This invention provides a drill pipe threaded connector, comprising a male connector 1 and a female connector 2. The male connector 1 includes an outer main shoulder surface 11 and an outer end face 17 perpendicular to the axial direction, and a threaded base section 12, an external thread section 13, an outer receiving cavity surface 14, an outer sealing inclined surface 15, and an outer cylindrical surface 16 extending axially between the outer main shoulder surface 11 and the outer end face 17. The female connector 2 includes an inner main shoulder surface 21 and an inner end face 27 perpendicular to the axial direction, and a threaded base section 12, an external thread section 13, an outer receiving cavity surface 14, an outer sealing inclined surface 15, and an outer cylindrical surface 16 extending axially between the inner main shoulder surface 21 and the inner end face 27. The structure includes an axially extending threaded boring section 22, an internal thread section 23, an inner cavity surface 24, an inner sealing slope 25, and an inner cylindrical surface 26. The external thread and the internal thread are interlocked. The outer cavity surface 14 does not contact the inner cavity surface 24 and forms a cavity 3. The cavity 3 is used to contain grease, air, and metal debris. The outer sealing slope 15 contacts the inner sealing slope 25 to provide a seal. There is a gap between the outer cylindrical surface 16 and the inner cylindrical surface 26, and there is a gap between the outer end face 17 and the inner end face 27.
[0028] Figure 2The outer sealing slope 15 of the male connector 1 includes a groove area 151 and a smooth area 152. The groove area 151 is located on the side of the outer sealing slope 15 near the outer receiving cavity surface 14, and the smooth area 152 is located on the side of the sealing slope near the outer cylindrical surface 16. The groove area 151 includes a plurality of grooves 1511, the area of which accounts for 10% to 50% of the area of the groove area 151. The axial projection length L1 of the smooth area 152 is 20% to 70% of the axial projection length L2 of the outer sealing slope 15.
[0029] Because metal debris is generated during the assembly and use of the joint, this debris may damage the sealing performance of the sealing bevel during subsequent high-pressure use. Therefore, a groove 1511 is actively provided on the sealing bevel to facilitate the collection of metal debris. Compared to debris being trapped between the sealing bevels, the presence of a groove allows the metal debris to enter, reducing friction between the sealing bevels. Furthermore, this design of the groove 1511 also facilitates the collection and containment of excess grease and air in the cavity during assembly, resulting in more precise torque during assembly. The area of the groove 1511 is defined as 10% to 50% of the area of the groove region 151, and the smooth surface region 152 is defined as 20% to 70% of the axial projection length of the outer sealing bevel. This design ensures both the collection of metal debris and the containment of grease and air while maintaining sealing performance, thus improving overall sealing reliability.
[0030] It is conceivable that a groove could be provided only on the inner sealing bevel 25 of the female connector 2. The inner sealing bevel 25 is also divided into a grooved area and a smooth area. The grooved area of the inner sealing bevel 25 is close to the inner cavity surface 24, and the smooth area of the inner sealing bevel 25 is close to the inner cylindrical surface 26. The groove on the inner sealing bevel 25 occupies 10% to 50% of the grooved area, and the smooth area of the inner sealing bevel 25 occupies 20% to 70% of the axial projection length of the inner sealing bevel 25. This can also serve the purpose of collecting metal debris and containing grease and air while ensuring sealing. By providing a groove only on one of the outer sealing bevel 15 or the inner sealing bevel 25, the sealing bevel with the groove will be in close contact with the groove, better ensuring that metal debris entering the groove will not escape, thus increasing the reliability of the seal.
[0031] Optionally, the groove is spirally arranged along the sealing slope, and the spiral direction of the groove is the same as the spiral direction of the thread. In this embodiment, the groove 1511 is provided on the outer sealing slope 15 for illustration. The groove 1511 is spirally arranged along the outer sealing slope 15, and the spiral direction of the groove 1511 should be the same as the spiral direction of the external thread. During the tightening process, the groove 1511 will also actively guide and accommodate metal debris and grease, resulting in better performance.
[0032] Optionally, continuing with groove 1511 as an example, groove 1511 gradually narrows in the direction where the spiral diameter decreases. This gradually narrowing groove 1511 better restricts the movement of metal debris. Please continue to refer to... Figure 3 The groove 1511 can also be discontinuous in the spiral direction. This spiral but discontinuous groove 1511 can play an active drainage role and also increase the contact area between the two sealing slopes, thereby enhancing the sealing performance.
[0033] Optionally, the included angle between the sidewall of the groove and the bottom surface of the groove is 80°~85°. In this embodiment, groove 1511 is used as an example for explanation; please refer to the following. Figure 4 The included angle A between the groove sidewall 15111 and the groove bottom surface 15112 of the groove 1511 is 80°~85°, which makes it difficult for metal debris to escape after entering the groove 1511, preventing the two sealing inclined surfaces from being worn by metal debris. In addition, if the joint has a slight tendency to rotate in the opposite direction under vibration load, the viscous grease or metal debris in the groove 1511 will generate greater resistance, forming a self-locking effect, which can increase the anti-loosening effect of the drill pipe.
[0034] Optionally, taking groove 1511 as an example, after laser hardening of groove 1511, the hardness of the groove sidewall 15111 and the groove bottom surface 15112 is greater than that of the other parts of the outer sealing inclined surface 15 excluding the groove. This increases the hardness of groove 1511 and can prevent fatigue cracks caused by alternating loads and high pressure after groove 1511 becomes a new stress concentration point, thus preventing joint breakage.
[0035] Optionally, the ratio of the depth to the width of the groove ranges from 0.1 to 1. In this embodiment, the ratio of the depth to the width of the groove 1511 ranges from 0.1 to 1 to balance the capacity and the overall stress of the sealing surface. If the ratio is too large, it may weaken the overall strength of the sealing surface.
[0036] Optionally, the roughness Ra of the sealing bevel, excluding the groove, is ≤1.6μm. In this embodiment, whether the groove 1511 is provided on the outer sealing bevel 15 or the groove is provided on the inner sealing bevel 25, the roughness Ra of the entire sealing bevel, excluding the groove, is ≤1.6μm, which can increase the sealing performance of the sealing bevel.
[0037] Optionally, the roughness of the smooth area is less than the roughness of the other parts of the groove area. In this embodiment, taking the outer sealing bevel 15 as an example, if the roughness of the smooth area 152 of the outer sealing bevel 15 is less than the roughness of the groove area 151 of the outer sealing bevel 15, then metal impurities, grease, and air are less likely to leak, and the sealing performance of the joint is better.
[0038] Those skilled in the art will understand that the steps, measures, and schemes in the various operations, methods, and processes discussed in this invention can be alternated, modified, combined, or deleted. Furthermore, other steps, measures, and schemes in the various operations, methods, and processes discussed in this invention can also be alternated, modified, rearranged, decomposed, combined, or deleted. Furthermore, steps, measures, and schemes in the prior art that are similar to those disclosed in this invention can also be alternated, modified, rearranged, decomposed, combined, or deleted.
[0039] In the description of this invention, it should be understood that the terms "center", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this 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. Therefore, they should not be construed as limitations on this invention.
[0040] The terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this invention, unless otherwise stated, "a plurality of" means two or more.
[0041] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.
[0042] In the description of this specification, specific features, structures, materials, or characteristics may be combined in any suitable manner in one or more embodiments or examples.
[0043] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.
Claims
1. A drill pipe threaded joint, characterized in that, include: The device includes a male connector and a female connector. The male connector includes a threaded base section, an external thread section, a receiving cavity surface, a sealing bevel surface, and a cylindrical surface that extend sequentially. The female connector includes a threaded boring section, an internal thread section, a receiving cavity surface, a sealing bevel surface, and a cylindrical surface that extend sequentially. The external thread and the internal thread engage with each other. The receiving cavity surface of the male connector does not contact the receiving cavity surface of the female connector and forms a receiving cavity. The sealing bevel surface of the male connector contacts the sealing bevel surface of the female connector. There is a gap between the cylindrical surface of the male connector and the cylindrical surface of the female connector. The sealing bevel of the male connector or the sealing bevel of the female connector includes a groove area and a smooth area along the axial direction. The groove area is located on the side of the sealing bevel closer to the receiving cavity surface, and the smooth area is located on the side of the sealing bevel closer to the cylindrical surface. The groove area includes a plurality of grooves, the area of which accounts for 10% to 50% of the area of the groove area. The axial projection length of the smooth area is 20% to 70% of the axial projection length of the sealing bevel.
2. The drill pipe threaded joint according to claim 1, characterized in that, The groove is spirally arranged along the sealing slope, and the spiral direction of the groove is the same as the spiral direction of the thread.
3. The drill pipe threaded joint according to claim 2, characterized in that, The groove gradually narrows along the direction in which its spiral diameter decreases.
4. The drill pipe threaded joint according to claim 2, characterized in that, The groove is discontinuous in its helical direction.
5. The drill pipe threaded joint according to claim 2, characterized in that, The angle between the sidewall and the bottom surface of the groove is 80°~85°.
6. The drill pipe threaded joint according to claim 5, characterized in that, The hardness of the sidewalls and bottom surface of the groove is greater than the hardness of the other parts of the sealing slope excluding the groove.
7. The drill pipe threaded joint according to claim 6, characterized in that, The groove is subjected to laser hardening.
8. The drill pipe threaded joint according to claim 1, characterized in that, The ratio of the depth to the width of the groove ranges from 0.1 to 1.
9. The drill pipe threaded joint according to claim 1, characterized in that, The roughness of the sealing bevel, excluding the groove, is less than 1.6 μm.
10. The drill pipe threaded joint according to claim 1, characterized in that, The roughness of the smooth area is less than the roughness of the other parts of the grooved area, excluding the groove itself.