Drill pipe construction and method of manufacture

Abstract

This invention relates to a drill pipe structure and manufacturing method, belonging to the field of oil drilling technology. The drill pipe structure of this invention includes a drill pipe body, a female connector, and a male connector. The drill pipe body includes a first section and second sections respectively disposed at both ends of the first section. The female connector is disposed at one end of the drill pipe body; the male connector is disposed at the end of the drill pipe body away from the female connector. The first section contains a first hole that penetrates the first section axially. The second section contains a second hole that communicates with the first hole and penetrates the second section axially. The diameter of the first section is smaller than the diameter of the second section, and the diameter of the first hole is larger than the diameter of the second hole. The technical solution disclosed in this invention can improve the mechanical properties of the drill pipe structure, making it more stable and safer when subjected to tensile, compressive, and torsional loads, effectively preventing drill pipe structure cracking.

Description

Technical Field

[0001] This invention relates to the field of oil drilling technology, and particularly to a drill pipe structure and manufacturing method. Background Technology

[0002] Drill pipe is a critical drilling tool used in oil drilling operations, playing a vital role. With the increasing number of deep wells, ultra-deep wells, and horizontal wells with extended reach, the fatigue loads on drill pipes downhole, including bending, torsion, and impact, are also constantly increasing. This leads to fatigue cracks at critical sections, inducing pipe leakage and ultimately causing drill pipe fracture. Therefore, developing a large-diameter, high-torque drill pipe with ultra-high torsional resistance in its threaded joints and reduced drilling fluid impact loads is imperative. Summary of the Invention

[0003] This invention provides a drill pipe structure and manufacturing method that can improve the mechanical properties of the drill pipe structure, making it more stable and safer when subjected to tensile, compressive, and torsional loads, and effectively preventing drill pipe structure cracking.

[0004] In a first aspect, embodiments of the present invention provide a drill pipe structure, comprising:

[0005] The drill pipe body includes a first section and second sections respectively disposed at both ends of the first section;

[0006] A female connector is provided at one end of the drill pipe body; and

[0007] The male connector is located at the end of the drill pipe body furthest from the female connector;

[0008] The first rod segment has a first hole segment that penetrates the first rod segment in the axial direction; the second rod segment has a second hole segment that communicates with the first hole segment and penetrates the second rod segment in the axial direction; and the diameter of the first rod segment is smaller than the diameter of the second rod segment, while the diameter of the first hole segment is larger than the diameter of the second hole segment.

[0009] In one embodiment, the first segment is a cylindrical segment; the second segment is a frustum segment, and the diameter of the end of the second segment away from the first segment is greater than the diameter of the end of the first segment closer to the first segment.

[0010] In one embodiment, the first hole segment is a cylindrical hole segment; the second hole segment includes a transition section and a straight section, and the two ends of the transition section are respectively connected to the straight section and the first hole segment;

[0011] The transition section is a frustum-shaped hole section, and the diameter of the end of the transition section away from the first hole section is smaller than the diameter of the end of the transition section close to the first hole section; the straight section is a cylindrical hole section.

[0012] In one embodiment, the taper of the second rod segment is 21 mm / m, and the taper of the transition section is 21 mm / m or 20.8 mm / m.

[0013] In one embodiment, the female connector has a female connector hole that communicates with the second hole segment; wherein, the male connector is configured to be threadedly connected to the female connector hole, and the male connector has a male connector hole that communicates with the second hole segment.

[0014] In one embodiment, the female connector hole is a frustum-shaped hole, and the diameter of the end of the female connector hole near the second hole segment is smaller than the diameter of the end of the female connector hole away from the second hole segment; wherein, the male connector hole is a cylindrical hole, and the male connector is frustum-shaped to match the shape of the female connector hole.

[0015] Secondly, embodiments of the present invention provide a manufacturing method for processing the drill pipe structure as described above, the manufacturing method comprising:

[0016] The drill rod blank is thickened at both ends by multiple forming processes, and the thickened drill rod blank is heat-treated to obtain the drill rod body;

[0017] The male connector blank is processed by machining, and then the machined male connector blank is heat-treated to obtain the male connector.

[0018] The female connector blank is processed by machining, and the machined female connector blank is then heat-treated to obtain the female connector.

[0019] The male connector and the female connector are connected to both ends of the drill pipe body by friction welding to obtain the drill pipe structure.

[0020] In one embodiment, the two ends of the drill rod blank are thickened through multiple forming processes, and the thickened drill rod blank is heat-treated to obtain the drill rod body, comprising:

[0021] The thickened drill rod blank is subjected to quenching and tempering treatment, wherein the quenching temperature is 930℃ and the tempering temperature is 600℃.

[0022] In one embodiment, the male connector and the female connector are connected to both ends of the drill pipe body by friction welding to obtain the drill pipe structure, comprising:

[0023] The friction surfacing welding was performed at a speed of 900±5% rpm, a welding pressure of 1800±5% psi, a holding time of 11s, and a required compression of 0.75in±5%.

[0024] In one implementation, it further includes:

[0025] The welded area after friction surfacing is subjected to quenching and tempering treatment, with a quenching temperature of 900℃ and a tempering temperature of 650℃.

[0026] Compared with the prior art, the advantages of the embodiments of the present invention are that by making the diameter of the first rod segment smaller than the diameter of the second rod segment, the drill rod body forms an externally thickened structure that is thicker in the middle and thicker at both ends. By making the diameter of the first hole segment larger than the diameter of the second hole segment, the through hole inside the drill rod body forms an internally thickened structure that is thicker in the middle and thinner at both ends. Thus, the drill rod body has both internally and externally thickened structures, which improves the connection strength between the drill rod body and the male and female connectors, improves the mechanical properties of the drill rod structure, and makes it more stable and safe when subjected to tensile, compressive, and torsional loads, effectively preventing the drill rod structure from cracking. Attached Figure Description

[0027] The invention will now be described in more detail with reference to embodiments and the accompanying drawings.

[0028] Figure 1 This is a three-dimensional structural diagram of a drill pipe structure provided in an embodiment of the present invention;

[0029] Figure 2 yes Figure 1 A cross-sectional view of the drill pipe structure provided in the embodiment;

[0030] Figure 3 yes Figure 1 A schematic diagram of the male connector provided in the embodiment;

[0031] Figure 4 yes Figure 1 A schematic diagram of the female connector provided in the embodiment;

[0032] Figure 5 yes Figure 1 A schematic diagram of the mating of the male and female connectors provided in the Chinese embodiment;

[0033] Figure 6 yes Figure 1 Tensile stress diagram of the drill pipe body provided in the Chinese embodiment;

[0034] Figure 7 yes Figure 1 Torsional stress diagram of the drill pipe body provided in the Chinese embodiment;

[0035] Figure 8This is a tensile stress diagram of the drill pipe body provided by existing technology;

[0036] Figure 9 It is a torsional stress diagram of the drill pipe body provided by existing technology;

[0037] Figure 10 This is a simulation diagram of the pressure loss of a drill pipe structure provided in an embodiment of the present invention;

[0038] Figure 11 This is a simulation diagram of the pressure loss of a drill pipe structure provided in another embodiment of the present invention;

[0039] Figure 12 This is a simulation diagram of the pressure loss of a drill pipe structure provided in another embodiment of the present invention;

[0040] Figure 13 for Figures 10-11 A comparison chart of pressure loss;

[0041] Figure 14 A flowchart of a manufacturing method provided for yet another embodiment of the present invention.

[0042] Figure label:

[0043] 10. Drill pipe body; 110. First section; 120. Second section; 130. First hole section; 140. Second hole section; 1401. Transition section; 1402. Straight section;

[0044] 20. Female connector; 210. Female connector hole; 220. Internal thread;

[0045] 30. Male connector; 310. Male connector hole; 320. External thread. Detailed Implementation

[0046] The invention will now be further described with reference to the accompanying drawings.

[0047] Drill pipe is a key drilling tool used in oil drilling operations and plays a vital role in oil drilling. With the continuous increase in the number of deep wells, ultra-deep wells, and horizontal wells with extended reach, the fatigue loads such as bending, torsion, and impact that drill pipes bear downhole are also increasing. This leads to fatigue cracks at their critical sections, inducing pipe leakage and ultimately causing serious failures such as drill pipe fracture.

[0048] Due to structural reasons, the thickened transition zone of the existing API standard drill pipe has a large difference between the thickened inner diameter and the inner diameter of the pipe. The drilling fluid generates eddies at the diameter change point, which puts a large impact load on the inner wall of the pipe. Fatigue cracks are prone to occur at this point. The fatigue cracks continue to extend, eventually causing the pipe to leak and fail.

[0049] In some well locations, the build-up point is shallow, resulting in significant horizontal displacement. During the later stages of drilling, the torque on the drill pipe joint increases substantially, increasing the risk of thread fatigue cracks. Therefore, developing a large-diameter, high-torque drill pipe with ultra-high torsional resistance in the joint thread and reduced drilling fluid impact load is imperative.

[0050] Example 1

[0051] To address the aforementioned technical problems, this invention provides a drill pipe structure, including a drill pipe body 10, a female connector 20, and a male connector 30. The drill pipe body 10 includes a first segment 110 and second segments 120 respectively disposed at both ends of the first segment 110. The female connector 20 is disposed at one end of the drill pipe body 10. The male connector 30 is disposed at the end of the drill pipe body 10 away from the female connector 20. A first hole segment 130 is provided within the first segment 110, and the first hole segment 130 penetrates the first segment 110 in the axial direction. A second hole segment 140 is provided within the second segment 120, communicating with the first hole segment 130, and the second hole segment 140 penetrates the second segment 120 in the axial direction. The diameter of the first segment 110 is smaller than the diameter of the second segment 120, and the diameter of the first hole segment 130 is larger than the diameter of the second hole segment 140.

[0052] As can be seen from the above, by making the diameter of the first rod segment 110 smaller than the diameter of the second rod segment 120, the drill rod body 10 forms an externally thickened structure that is thicker in the middle and thicker at both ends. By utilizing the fact that the diameter of the first hole segment 130 is larger than the diameter of the second hole segment 140, the through hole inside the drill rod body 10 forms an internally thickened structure that is thicker in the middle and thinner at both ends. Thus, the drill rod body 10 has both internally and externally thickened structures, which improves the connection strength between the drill rod body 10 and the male connector 30 and the female connector 20, improves the mechanical properties of the drill rod structure, and makes it more stable and safer when subjected to tensile, compressive, and torsional loads, effectively preventing the drill rod structure from cracking.

[0053] It should be noted that the length of the drill pipe body 10 is 8.6m, the length of the second section 120 is 300mm, and the thickness of the end of the second drill pipe away from the first drill pipe is 17.2mm.

[0054] It should also be noted that the outer diameters of both the male connector 30 and the female connector 20 are larger than the outer diameter of the drill pipe body 10. During the drilling process, the male connector 30 and the female connector 20 will continuously come into contact with and rub against the well wall and casing, resulting in wear. In order to avoid drilling accidents such as drill pipe breakage and disengagement caused by joint wear, both the female connector 20 and the male connector 30 are equipped with anti-wear strips to improve wear resistance.

[0055] It should also be noted that the male connector 30, the female connector 20, and the drill pipe body 10 are coaxially arranged.

[0056] Example 2

[0057] like Figures 1-5 As shown, the drill pipe structure includes a drill pipe body 10, a female connector 20, and a male connector 30. The drill pipe body 10 includes a first section 110 and second sections 120 respectively disposed at both ends of the first section 110. The female connector 20 is disposed at one end of the drill pipe body 10. The male connector 30 is disposed at the end of the drill pipe body 10 away from the female connector 20. The first section 110 has a first hole section 130 that penetrates the first section 110 in the axial direction. The second section 120 has a second hole section 140 that communicates with the first hole section 130 and penetrates the second section 120 in the axial direction. The diameter of the first section 110 is smaller than the diameter of the second section 120, and the diameter of the first hole section 130 is larger than the diameter of the second hole section 140.

[0058] As can be seen from the above, by making the diameter of the first rod segment 110 smaller than the diameter of the second rod segment 120, the drill rod body 10 forms an externally thickened structure that is thicker in the middle and thicker at both ends. By utilizing the fact that the diameter of the first hole segment 130 is larger than the diameter of the second hole segment 140, the through hole inside the drill rod body 10 forms an internally thickened structure that is thicker in the middle and thinner at both ends. Thus, the drill rod body 10 has both internally and externally thickened structures, which improves the connection strength between the drill rod body 10 and the male connector 30 and the female connector 20, improves the mechanical properties of the drill rod structure, and makes it more stable and safer when subjected to tensile, compressive, and torsional loads, effectively preventing the drill rod structure from cracking.

[0059] It should be noted that the length of the drill pipe body 10 is 8.6m, the length of the second section 120 is 300mm, and the thickness of the end of the second drill pipe away from the first drill pipe is 17.2mm.

[0060] It should also be noted that the outer diameters of both the male connector 30 and the female connector 20 are larger than the outer diameter of the drill pipe body 10. During the drilling process, the male connector 30 and the female connector 20 will continuously come into contact with and rub against the well wall and casing, resulting in wear. In order to avoid drilling accidents such as drill pipe breakage and disengagement caused by joint wear, both the female connector 20 and the male connector 30 are equipped with anti-wear strips to improve wear resistance.

[0061] It should also be noted that the male connector 30, the female connector 20, and the drill pipe body 10 are coaxially arranged.

[0062] In some embodiments, the first segment 110 is a cylindrical segment; the second segment 120 is a frustum segment, and the diameter of the end of the second segment 120 away from the first segment 110 is greater than the diameter of the end of the first segment 110 close to the first segment 110.

[0063] By setting the second rod segment 120 as a frustum rod segment, and the diameter of the end of the second rod segment 120 away from the first rod segment 110 is greater than the diameter of the end of the first rod segment 110 close to the first rod segment 110, the thickness of the outer thickening is further increased, thereby further thickening both ends of the drill pipe body 10 and improving the mechanical properties of the entire drill pipe structure.

[0064] It should be noted that the diameter of the end of the second rod segment 120 closest to the first rod segment 110 is equal to the diameter of the first rod segment 110. This avoids the formation of a stepped structure, reduces stress, prevents stress concentration in the drill pipe during operation, and effectively prevents cracking of critical parts of the drill pipe.

[0065] In some embodiments, the first hole segment 130 is a cylindrical hole segment; the second hole segment 140 includes a transition section 1401 and a straight section 1402, the two ends of the transition section 1401 being connected to the straight section 1402 and the first hole segment 130 respectively; wherein, the transition section 1401 is a frustum hole segment, and the diameter of the end of the transition section 1401 away from the first hole segment 130 is smaller than the diameter of the end of the transition section 1401 close to the first hole segment 130; the straight section 1402 is a cylindrical hole segment.

[0066] By setting the transition section 1401 as a frustum-shaped bore section, and ensuring that the diameter of the end of the transition section 1401 furthest from the first bore section 130 is smaller than the diameter of the end of the transition section 1401 closest to the first bore section 130, the thickness of the inner thickening is further increased, thereby further thickening both ends of the drill pipe body 10 and improving the mechanical properties of the entire drill pipe structure. The transition section 1401 connects the straight section 1402 with the first bore section 130, allowing for a smooth transition between the two sections with different diameters. This avoids the drilling fluid generating eddies at the diameter change point due to the different diameters, which could cause significant impact loads on the inner wall of the drill pipe body 10, leading to fatigue cracks that propagate and ultimately cause drill pipe leakage failure.

[0067] It should be noted that the length of the transition section 1401 is 135mm.

[0068] It should also be noted that the diameter of the end of the transition section 1401 closest to the first hole section 130 is equal to the diameter of the first hole section 130, thereby avoiding the generation of eddies at the connection between the transition section 1401 and the first hole section 130 due to the difference in diameter.

[0069] In some embodiments, the taper of the second segment 120 is 21 mm / m, and the taper of the transition segment 1401 is 21 mm / m or 20.8 mm / m.

[0070] By limiting the taper of the second section 120, the excessive taper of the second section 120 is avoided, which would increase the size of the drill pipe body 10 and cause friction between the drill pipe body 10 and the well wall, affecting drilling operations. Conversely, the excessive taper of the second section 120 is also avoided, which would result in insufficient thickness at both ends of the drill pipe body 10, affecting its mechanical properties. Similarly, by limiting the taper of the transition section 1401, normal drilling fluid flow is ensured while providing a smooth connection, preventing the generation of eddies. This avoids both excessively large tapers in the transition section 1401 affecting drilling fluid flow and excessively small tapers in the transition section 1401, which would result in insufficient thickness at both ends of the drill pipe body 10, affecting its mechanical properties.

[0071] In some embodiments, the female connector 20 is provided with a female connector hole 210, which is connected to the second hole segment 140; wherein, the male connector 30 is configured to be threadedly connected to the female connector hole 210, and the male connector 30 is provided with a male connector hole 310 that is connected to the second hole segment 140.

[0072] By providing a male connector 30 that can be threaded into the female connector hole 210, a structural basis is provided for the connection between multiple drill pipe structures, allowing for increased length and facilitating drilling operations. Additionally, the male connector hole 310 provides a structural basis for the flow of drilling fluid within the drill pipe structure.

[0073] It should be noted that the diameter of the female connector hole 210 at the end near the drill rod body 10 is equal to the diameter of the straight section 1402; the diameter of the male connector hole 310 at the end near the drill rod body 10 is equal to the diameter of the straight section 1402.

[0074] It should also be noted that the female connector hole 210 is provided with an internal thread 220, and the male connector 30 is provided with an external thread 320.

[0075] In some embodiments, the female connector hole 210 is a frustum hole, and the diameter of the end of the female connector hole 210 near the second hole segment 140 is smaller than the diameter of the end of the female connector hole 210 away from the second hole segment 140; wherein, the male connector hole 310 is a cylindrical hole, and the male connector 30 is frustum shaped to match the shape of the female connector hole 210.

[0076] By setting the female connector hole 210 as a frustum and the male connector 30 as a frustum, they can match the shape of the female connector hole 210, enhancing the connection and torsional strength between the female connector 20 and the male connector 30. At the same time, compared with the traditional API standard drill pipe, the male connector 30 and female connector 20 in this invention have a smaller taper at the tapered thread connection, and the thread connection length of the male connector 30 and female connector 20 is increased to ensure enhanced thread connection strength. The reduced taper at the thread connection increases the diameter of the drill pipe body 10 and the male connector 30 and female connector 20 at the interface position. Under the premise that the maximum diameter of the drill pipe body 10 remains unchanged, the taper of the second hole section 140 is smaller, thereby reducing the circulating pressure loss, reducing the impact of fluid erosion on the drill pipe structure, and adapting to drilling operations under high pump pressure, large displacement, and high torque conditions.

[0077] Figure 6 The diagram shown is a tensile stress diagram of the drill pipe body 10 provided by the present invention. Figure 7 This is a torsional stress diagram of the drill pipe body 10 provided by the present invention. Figure 8 The diagram shown is a tensile stress diagram of the drill pipe body 10 provided by the prior art. Figure 9 The torsional stress diagram of the drill pipe body 10 provided by the prior art is obtained through... Figures 6-9 It can be seen that, whether under tension or torsion conditions, the equivalent stress of the drill pipe body 10 provided by the present invention is smaller than that of the drill pipe body 10 provided by the prior art under the same load conditions, and its mechanical properties are superior to those of the drill pipe body 10 in the prior art.

[0078] Figure 10 The figure shown is a simulation diagram of the pressure loss of the drill pipe structure provided by the present invention. The buckle type is WMT54 and the inner diameter of the water hole is 101.6mm. Figure 11 The simulation diagram of pressure loss of the drill pipe structure provided by the present invention uses NC50 as the snap-fit ​​type and the inner diameter of the water hole is 69.9mm; Figure 12 The simulation diagram of pressure loss of the drill pipe structure provided by the present invention uses NC50 as the snap-fit ​​type and the inner diameter of the water hole is 101.6mm; Figure 13 for Figures 10-11 The pressure loss comparison chart shows that the WMT54 buckle with a water inlet diameter of 101.6mm has the lowest pressure loss.

[0079] Among them, NC50 is the standard for oil well threaded connections. The thread type adopts a tapered thread form, that is, both the external thread 320 and the internal thread 210 are tapered; the thread length is 101.48mm, the pitch is 6.35mm, the thread angle is 60°, and the thread profile is a rounded rectangle.

[0080] WMT54 is a standard for oil well threaded connections. The thread type is a tapered thread, that is, both the external thread 320 and the internal thread 210 are tapered; the thread length is 107.95mm, the pitch is 7.257mm, the thread angle is 60°, and the thread profile is a rounded rectangle.

[0081] In summary, the drill pipe structure provided by this invention effectively reduces the stress concentration in the transition section 1401, improves the stress distribution, and increases the fatigue life of the thickened transition section 1401 by selecting parameters such as thread type, joint thread type, and water hole diameter; it also enhances the connection and torsional strength of the threaded joint, increases the inner diameter of the joint, reduces circulating pressure loss, and adapts to current drilling enhancement parameters (high pump pressure, large displacement, and high torque) in construction operations.

[0082] Example 3

[0083] like Figure 14 As shown, this embodiment of the invention provides a manufacturing method applied to processing the drill pipe structure as described in any embodiment, the manufacturing method comprising:

[0084] S101: The two ends of the drill rod blank are thickened by multiple forming processes, and the thickened drill rod blank is heat-treated to obtain the drill rod body 10.

[0085] It should be noted that the drill pipe blank can be a seamless steel pipe, which is thickened at both ends through three forming processes; the forming process includes, but is not limited to, turning.

[0086] In some embodiments, the two ends of the drill rod blank are thickened through multiple forming processes, and the thickened drill rod blank is heat-treated to obtain the drill rod body 10, comprising:

[0087] The thickened drill rod blank is subjected to quenching and tempering treatment, wherein the quenching temperature is 930℃ and the tempering temperature is 600℃.

[0088] It should be noted that heat treatment of the thickened drill rod blank through tempering can improve its strength, plasticity and toughness. The drill rod blank is first heated and quenched, then rapidly cooled to obtain hardness and brittleness, and then tempered at 600℃ to eliminate the internal stress and brittleness generated by quenching, thereby improving the toughness and plasticity of the material.

[0089] S102: The male connector 30 blank is processed by machining, and the machined male connector 30 blank is heat-treated to obtain the male connector 30.

[0090] It should be noted that the male connector 30 blank is processed by machining, including: precision turning of the stop, rough machining of the thread surface, cutting the thread length in 4 cuts, turning the radial direction twice, precision turning of the thread outer tapered surface, continuing to turn 3 times, leaving a thread allowance of 0.15mm on one side, precision turning twice, turning the inner end face, and turning the 55° tapered surface.

[0091] S103: The blank of the female connector 20 is processed by machining, and the machined blank of the female connector 20 is heat-treated to obtain the female connector 20.

[0092] It should be noted that the female connector 20 blank is processed by machining, including: precision turning of the stop, rough machining of the thread surface, cutting the thread length in 4 cuts, turning the radial direction twice, precision turning of the inner tapered surface of the thread, turning three more times, leaving a 0.15mm allowance on one side of the thread, precision turning twice, turning the inner end face, and turning the 55° tapered surface.

[0093] It should also be noted that the heat treatment of the machined male connector 30 billet and female connector 20 billet includes: quenching and tempering treatment of the machined male connector 30 billet and female connector 20 billet, wherein the quenching temperature is 930℃ and the tempering temperature is 600℃, and high-speed stirring is performed during quenching. The male connector 30 billet and female connector 20 billet are placed vertically and in a straight line, and the outer diameter interval of the connector tongs is greater than 50mm. The connector tongs are tools used in oil drilling operations for quickly threading, mainly used for threading and tightening drill string threads during tripping and casing operations. High-speed stirring during quenching can accelerate the cooling rate of the steel surface, prevent the formation of gas film, and enable the steel to reach the ideal hardness.

[0094] S104: The male connector 30 and the female connector 20 are connected to both ends of the drill pipe body 10 by friction welding to obtain the drill pipe structure.

[0095] In some embodiments, the male connector 30 and the female connector 20 are connected to both ends of the drill pipe body 10 by friction welding to obtain the drill pipe structure, which includes:

[0096] The friction surfacing welding was performed at a speed of 900±5% rpm, a welding pressure of 1800±5% psi, a holding time of 11s, and a required compression of 0.75in±5%.

[0097] In some embodiments, the method further includes: performing a tempering treatment on the welded area after friction surfacing, wherein the quenching temperature is 900°C and the tempering temperature is 650°C.

[0098] It should be noted that the surfaces of the drill pipe body 10, male connector 30, and female connector 20 to be welded should not have rust, oil stains, or other impurities before friction welding, so as to avoid affecting the welding effect.

[0099] It should also be noted that after the friction welding is completed, the parallelism deviation and angle of the drill pipe structure should be checked. The measurement results should meet the requirements of parallelism deviation and coaxiality, with a total reading of ≤0.9mm (0.036in) and angular deviation of ≤3mm / m (0.005in / in).

[0100] It should also be noted that using friction welding to connect the drill rod body 10, the male connector 30 and the female connector 20 can significantly improve processing efficiency and significantly reduce equipment investment costs. Furthermore, friction welding does not require high-temperature heating, which also reduces the impact of heating on the material's microstructure and properties.

[0101] It should also be noted that by processing the drill pipe body 10, male connector 30, and female connector 20 separately, and then connecting the drill pipe body 10, male connector 30, and female connector 20 by friction welding, the production efficiency is higher.

[0102] Although the invention has been described with reference to preferred embodiments, various modifications can be made and components can be replaced with equivalents without departing from the scope of the invention. In particular, the technical features mentioned in the various embodiments can be combined in any manner as long as there is no structural conflict. The invention is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A drill pipe structure, characterized in that, include: The drill pipe body includes a first section and second sections respectively disposed at both ends of the first section; A female connector is provided at one end of the drill pipe body; and The male connector is located at the end of the drill pipe body furthest from the female connector; The first rod segment has a first hole segment that penetrates the first rod segment in the axial direction; the second rod segment has a second hole segment that communicates with the first hole segment and penetrates the second rod segment in the axial direction; and the diameter of the first rod segment is smaller than the diameter of the second rod segment, while the diameter of the first hole segment is larger than the diameter of the second hole segment.

2. The drill pipe structure according to claim 1, characterized in that, The first segment is a cylindrical segment; the second segment is a frustum segment, and the diameter of the end of the second segment away from the first segment is greater than the diameter of the end of the first segment closer to the first segment.

3. The drill pipe structure according to claim 2, characterized in that, The first hole segment is a cylindrical hole segment; the second hole segment includes a transition section and a straight section, and the two ends of the transition section are respectively connected to the straight section and the first hole segment; The transition section is a frustum-shaped hole section, and the diameter of the end of the transition section away from the first hole section is smaller than the diameter of the end of the transition section close to the first hole section; the straight section is a cylindrical hole section.

4. The drill pipe structure according to claim 3, characterized in that, The taper of the second rod segment is 21 mm / m, and the taper of the transition section is 21 mm / m or 20.8 mm / m.

5. The drill pipe structure according to any one of claims 1-4, characterized in that, The female connector has a female connector hole that communicates with the second hole segment; the male connector is configured to be threadedly connected to the female connector hole, and the male connector has a male connector hole that communicates with the second hole segment.

6. The drill pipe structure according to claim 5, characterized in that, The female connector hole is a frustum-shaped hole, and the diameter of the end of the female connector hole closer to the second hole segment is smaller than the diameter of the end of the female connector hole farther from the second hole segment; wherein, the male connector hole is a cylindrical hole, and the male connector is frustum-shaped to match the shape of the female connector hole.

7. A manufacturing method, characterized in that, The manufacturing method, applied to the processing of drill pipe structures as described in any one of claims 1-6, comprises: The drill rod blank is thickened at both ends by multiple forming processes, and the thickened drill rod blank is heat-treated to obtain the drill rod body; The male connector blank is processed by machining, and then the machined male connector blank is heat-treated to obtain the male connector. The female connector blank is processed by machining, and the machined female connector blank is then heat-treated to obtain the female connector. The male connector and the female connector are connected to both ends of the drill pipe body by friction welding to obtain the drill pipe structure.

8. The manufacturing method according to claim 7, characterized in that, The drill rod blank is thickened at both ends through multiple forming processes, and then the thickened drill rod blank is heat-treated to obtain the drill rod body, comprising: The thickened drill rod blank is subjected to quenching and tempering treatment, wherein the quenching temperature is 930℃ and the tempering temperature is 600℃.

9. The manufacturing method according to claim 7, characterized in that, The drill pipe structure is obtained by connecting the male connector and the female connector to both ends of the drill pipe body through friction welding, comprising: The friction surfacing welding was performed at a speed of 900±5% rpm, a welding pressure of 1800±5% psi, a holding time of 11s, and a required compression of 0.75in±5%.

10. The manufacturing method according to claim 7, characterized in that, Also includes: The welded area after friction surfacing is subjected to quenching and tempering treatment, with a quenching temperature of 900℃ and a tempering temperature of 650℃.

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