Direct connection type screwed joint

Abstract

The utility model provides a direct connection type screwed joint. The direct connection type threaded connector comprises an inner threaded connector. Along the axis, the external thread connector is sequentially provided with a first outer circular bead, a first outer sealing face, a first thread, a first groove, a first inner sealing face and a first inner circular bead from the outer side to the inner side, and the internal thread connector is sequentially provided with a second outer circular bead, a second outer sealing face, a second groove, a second thread, a second inner sealing face and a second inner circular bead from the outer side to the inner side. The first outer sealing surface is in sealing fit with the second outer sealing surface, the first inner sealing surface is in sealing fit with the second inner sealing surface, the first outer circular bead is in contact with the second outer circular bead, and the first inner circular bead is in clearance fit with the second inner circular bead. According to the technical scheme, the direct-connection type threaded connector has excellent external pressure resistance sealing performance and compression resistance performance, can be used for complex well conditions with small well holes, large annular gaps and strict requirements for external pressure resistance performance and compression resistance performance, and can reduce the stress level of the nose end.

Description

Technical Field

[0001] The utility model relates to the technical field of oil and gas exploitation, and particularly to a direct-connection type threaded joint. Background Technique

[0002] Compared with the coupling type casing threaded joint, since the direct-connection type threaded joint is flush inside and outside, the probability of pipe string encountering resistance when running in hole in some oil and gas wells such as horizontal wells and deviated wells is smaller; moreover, the outer diameter of the direct-connection type threaded joint is much smaller than that of the coupling type casing threaded joint, so that the direct-connection type threaded joint can increase the annular clearance of the wellbore and facilitate the subsequent downhole operations.

[0003] Chinese Patent CN105604499 discloses an invention patent named "A Direct-connection Type Double Shoulder Threaded Joint". This patented technology adopts a two-stage thread design method, and the sealing structure and shoulder part are both designed in the middle. This patented technology has certain sealing performance and high connection strength. However, since there is no sealing structure designed at the male and female pipe ends in this technology, internal and external fluids are likely to enter the thread part, resulting in a reduction in external pressure resistance performance, and at the same time causing corrosion of the threads, and the internal and external sealing performance cannot reach 100% of the pipe body.

[0004] Chinese Patent CN207278202 discloses a patent named "Direct-connection Type Casing Threaded Joint". This patented technology is designed with a special internal sealing structure and external sealing structure, and has excellent internal and external sealing performance and compression resistance performance. However, due to the need for interference contact of both the internal shoulder and the external shoulder during make-up and connection, its make-up torque is very high, which is inconvenient for on-site operation in the oilfield. Moreover, it requires very high machining accuracy for the threaded joint, otherwise there may be only one end shoulder in contact or one of the shoulders with interference contact at both ends is overstressed and yields.

[0005] Chinese Patent CN211422548 discloses an invention patent named "Direct-connection Type Casing Threaded Joint". This patented technology is designed with a special internal sealing structure and external sealing structure, and has excellent internal and external sealing performance and compression resistance performance. A complex transition surface is designed between the external sealing surface and the external shoulder of its internal threaded joint, and at the same time, a complex transition surface is designed between the internal sealing surface and the internal shoulder of its external threaded joint, resulting in low machining efficiency; secondly, there is no groove structure design between the sealing surface and the thread, resulting in a relatively high stress level at the nose end. Content of the Utility Model

[0006] The main object of the utility model is to provide a direct-connection type threaded joint. This direct-connection type threaded joint not only has excellent external pressure resistance sealing performance and compression resistance performance, can be used in complex well conditions with small wellbores, large annular clearances required, and strict requirements for external pressure performance and compression resistance performance, but also can reduce the stress level at the nose end.

[0007] To achieve the above object, the present utility model provides a direct connection type threaded joint. The direct connection type threaded joint has an axis, and the direct connection type threaded joint includes: an internal threaded joint; an external threaded joint, at least a part of the external threaded joint extends into the internal threaded joint. Along the axis, the external threaded joint is successively provided with a first external shoulder, a first external sealing surface, a first thread, a first groove, a first internal sealing surface, and a first internal shoulder from the outside to the inside. The internal threaded joint is successively provided with a second external shoulder, a second external sealing surface, a second groove, a second thread, a second internal sealing surface, and a second internal shoulder from the outside to the inside; the external threaded joint and the internal threaded joint are connected by the first thread and the second thread, and the first external sealing surface and the second external sealing surface are in sealing fit, the first internal sealing surface and the second internal sealing surface are in sealing fit. When the first external shoulder and the second external shoulder contact, the first internal shoulder and the second internal shoulder are in clearance fit.

[0008] Further, there is a distance L between the midpoint of the first external sealing surface and the first external shoulder 10 , the distance L 10 and the length L of the second external sealing surface 20 satisfy the relationship: L 10 / L 20 = 0.3 to 1.2; and / or, the length L of the first external sealing surface 11 and the length L of the second external sealing surface 20 satisfy the relationship: L 11 / L 20 = 0.15 to 1.

[0009] Further, there is a distance L between the midpoint of the second internal sealing surface and the second internal shoulder 22 , the distance L 22 and the length L of the first internal sealing surface 12 satisfy the relationship: L 22 / L 12 = 0.3 to 1.2; and / or, the length L of the second internal sealing surface 21 and the length L of the first internal sealing surface 12 satisfy the relationship: L 21 / L 12 = 0.15 to 1.

[0010] Further, the first external shoulder is inclined with respect to the axis. Along the axis, in the direction from the outside to the inside, the distance between the first external shoulder and the axis gradually increases; the second external shoulder is inclined with respect to the axis. Along the axis, in the direction from the outside to the inside, the distance between the second external shoulder and the axis gradually increases, and the first external shoulder and the second external shoulder are in interference fit.

[0011] Further, there is an angle α1 between the first outer shoulder and the cross-section of the external thread joint, and the range of the angle α1 is: 0° ≤ α1 ≤ 15°. There is an angle β1 between the second outer shoulder and the cross-section of the internal thread joint, and the range of the angle β1 is: 0° ≤ β1 ≤ 15°, and it satisfies: 0° ≤ α1 - β1 ≤ 1°.

[0012] Further, the first outer sealing surface is inclined with respect to the axis. Along the axis, in the direction from the outside to the inside, the distance between the first outer sealing surface and the axis gradually decreases; the second outer sealing surface is inclined with respect to the axis. Along the axis, in the direction from the outside to the inside, the distance between the second outer sealing surface and the axis gradually decreases, and the first outer sealing surface and the second outer sealing surface are in interference fit.

[0013] Further, there is an angle α2 between the first outer sealing surface and the axis, and the range of the angle α2 is: 3.50° ≤ α2 ≤ 9.90°. There is an angle β2 between the second outer sealing surface and the axis, and the range of the angle β2 is: 3.50° ≤ β2 ≤ 9.90°, and it satisfies: 0° ≤ α2 - β2 ≤ 1.5°.

[0014] Further, a first connecting surface is also provided on the external thread joint. The first connecting surface is connected between the first outer sealing surface and the first outer shoulder. The first connecting surface is arranged at an angle with the first outer sealing surface, and the first connecting surface is lower than or flush with one end of the first outer sealing surface facing the first outer shoulder; or, along the axis, the first outer sealing surface extends from the first outer shoulder to the first thread.

[0015] Further, the first inner sealing surface is inclined with respect to the axis. Along the axis, in the direction from the outside to the inside, the distance between the first inner sealing surface and the axis gradually decreases; the second inner sealing surface is inclined with respect to the axis. Along the axis, in the direction from the outside to the inside, the distance between the second inner sealing surface and the axis gradually decreases, and the first inner sealing surface and the second inner sealing surface are in interference fit.

[0016] Further, there is an angle α3 between the first inner sealing surface and the axis, and the range of the angle α3 is: 3.50° ≤ α3 ≤ 9.90°. There is an angle β3 between the second inner sealing surface and the axis, and the range of the angle β3 is: 3.50° ≤ β3 ≤ 9.90°, and it satisfies: 0° ≤ β3 - α3 ≤ 1.5°.

[0017] Further, a second connecting surface is also provided on the internal thread joint. The second connecting surface is connected between the second inner sealing surface and the second inner shoulder. The second connecting surface is arranged at an angle with the second inner sealing surface, and the second connecting surface is lower than or flush with one end of the second inner sealing surface facing the second inner shoulder; or, along the axis, from the outside to the inside, the second inner sealing surface extends from the second thread to the second inner shoulder.

[0018] Further, the first inner shoulder is inclined with respect to the axis, and along the axis, in the direction from the outside to the inside, the distance between the first inner shoulder and the axis gradually increases; the second inner shoulder is inclined with respect to the axis, and along the axis, in the direction from the outside to the inside, the distance between the second inner shoulder and the axis gradually increases; there is an angle α4 between the first inner shoulder and the cross-section of the external thread joint, and the range of the angle α4 is: 0° ≤ α4 ≤ 15°, and there is an angle β4 between the second inner shoulder and the cross-section of the internal thread joint, and the range of the angle β4 is: 0° ≤ β4 ≤ 15°.

[0019] Further, the length L of the second inner sealing surface 21 ranges from: 2 mm ≤ L 21 ≤ 5 mm; and / or, the length L of the first outer sealing surface 11 ranges from: 2 mm ≤ L 11 ≤ 5 mm.

[0020] Applying the technical solution of the present utility model, on the one hand, an inner sealing portion is formed by the first inner sealing surface and the second inner sealing surface in sealing fit, an outer sealing portion is formed by the first outer sealing surface and the second outer sealing surface in sealing fit, and the first thread and the second thread are connected to form a threaded portion. By adopting an independent inner sealing portion, the direct-connected threaded joint has excellent internal pressure sealing performance. At the same time, by adopting an independent outer sealing portion, the direct-connected threaded joint has excellent external sealing performance. Moreover, the inner sealing portion and the outer sealing portion are respectively located on both sides of the threaded portion, which can prevent external media from entering the threaded part and causing stress corrosion. The internal and external double seals enable the internal and external sealing performance of the direct-connected threaded joint to reach 100% of the pipe body. On the other hand, when the user uses it, the internal threaded joint and the external threaded joint are screwed together according to the specified make-up torque, and the first outer shoulder and the second outer shoulder come into contact, while there is a gap between the first inner shoulder and the second inner shoulder. The gap between the first inner shoulder and the second inner shoulder can provide a certain amount of compression space in the axial direction of the direct-connected threaded joint. When the direct-connected threaded joint bears a large compression load, contact occurs between the first outer shoulder and the second outer shoulder as well as between the first inner shoulder and the second inner shoulder, enabling the compression performance of the direct-connected threaded joint to reach 100% of the joint connection strength. This not only greatly facilitates the use in the oilfield site but also can avoid the problem of excessive yield due to the low machining accuracy of the direct-connected threaded joint resulting in excessive stress on one of the shoulders. On the further hand, by providing a second groove between the second outer sealing surface and the second thread, not only can the axial stiffness of the second nose end of the internal threaded joint be reduced, but also the stress release effect can be achieved. By providing a first groove between the first thread and the first inner sealing surface, not only can the axial stiffness of the first nose end of the external threaded joint be reduced, but also the stress release effect can be achieved. Thereby, the anti-compression performance of the direct-connected threaded joint can be further improved. In this way, not only can the stress level at the nose end be reduced, but also the complex transition surfaces between the outer seal and the outer shoulder as well as between the inner sealing surface and the inner shoulder can be avoided to reduce the machining difficulty, thereby improving the machining efficiency. In summary, the direct-connected threaded joint of the present utility model not only has excellent external pressure sealing performance and anti-compression performance and can be used in complex well conditions with small wellbores, large annulus clearances required, and strict requirements for external pressure performance and anti-compression performance, but also can reduce the stress level at the nose end and improve the machining efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The specification drawings forming a part of this application are used to provide a further understanding of the present utility model. The schematic embodiments of the present utility model and their descriptions are used to explain the present utility model and do not constitute an improper limitation to the present utility model. In the drawings:

[0022] Figure 1 The structural schematic diagram of the embodiment of the direct-connected threaded joint of the present utility model is shown;

[0023] Figure 2 Shows Figure 1 The structural schematic diagram of the external thread joint of the direct connection type thread joint;

[0024] Figure 3 Shows Figure 1 The structural schematic diagram of the internal thread joint of the direct connection type thread joint;

[0025] Figure 4 Shows Figure 2 The partial enlarged view at A1 of the external thread joint;

[0026] Figure 5 Shows Figure 2 The partial enlarged view at C1 of the external thread joint (provided with the first groove);

[0027] Figure 6 Shows Figure 3 The partial enlarged view at A2 of the internal thread joint (provided with the second groove);

[0028] Figure 7 Shows Figure 3 The partial enlarged view at C2 of the internal thread joint;

[0029] Figure 8 Shows Figure 3 The partial enlarged view at A2 of the internal thread joint (not provided with the second groove);

[0030] Figure 9 Shows Figure 2 The partial enlarged view at C1 of the external thread joint (not provided with the first groove);

[0031] Figure 10 Shows Figure 2 The partial enlarged view at A1 of the external thread joint (not provided with the first connection surface);

[0032] Figure 11 Shows Figure 3 The partial enlarged view at C2 of the internal thread joint (not provided with the second connection surface).

[0033] Among them, the above-mentioned drawings include the following reference numerals:

[0034] 1. External thread joint; 2. Internal thread joint; 10. First external shoulder; 11. First connection surface; 12. First external sealing surface; 13. First groove; 14. First internal sealing surface; 15. First internal shoulder; 16. First nose end; 17. First thread; 20. Second external shoulder; 21. Second external sealing surface; 22. Second groove; 23. Second internal sealing surface; 24. Second connection surface; 25. Second internal shoulder; 26. Second nose end; 27. Second thread. Specific embodiments

[0035] It should be noted that, without conflict, the embodiments in the present application and the features in the embodiments may be combined with each other. The present utility model will be described in detail below with reference to the drawings and in conjunction with the embodiments.

[0036] It should be noted that the direct-connection type threaded joint in the embodiment of the present utility model is a tubular connecting element in the technical field of oil pipes, and can be a direct-connection type casing threaded joint or a direct-connection type tubing threaded joint.

[0037] As Figures 1 to 11 shown, the embodiment of the present utility model provides a direct-connection type threaded joint. The direct-connection type threaded joint has an axis L, and the direct-connection type threaded joint includes an internal threaded joint 2 and an external threaded joint 1. Among them, at least a part of the external threaded joint 1 extends into the internal threaded joint 2. Along the axis L, the external threaded joint 1 is sequentially provided with a first outer shoulder 10, a first outer sealing surface 12, a first thread 17, a first groove 13, a first inner sealing surface 14 and a first inner shoulder 15 from the outside to the inside, and the internal threaded joint 2 is sequentially provided with a second outer shoulder 20, a second outer sealing surface 21, a second groove 22, a second thread 27, a second inner sealing surface 23 and a second inner shoulder 25 from the outside to the inside; the external threaded joint 1 and the internal threaded joint 2 are connected by the first thread 17 and the second thread 27, and the first outer sealing surface 12 and the second outer sealing surface 21 are in sealing fit, and the first inner sealing surface 14 and the second inner sealing surface 23 are in sealing fit. When the first outer shoulder 10 and the second outer shoulder 20 are in contact, the first inner shoulder 15 and the second inner shoulder 25 are in clearance fit.

[0038] In the above technical solution, on the one hand, the first inner sealing surface 14 and the second inner sealing surface 23 that are hermetically fitted form an inner sealing portion, the first outer sealing surface 12 and the second outer sealing surface 21 that are hermetically fitted form an outer sealing portion, and the first thread 17 and the second thread 27 are connected to form a threaded portion. By adopting an independent inner sealing portion, the direct-connection type threaded joint has excellent internal pressure sealing performance. At the same time, by adopting an independent outer sealing portion, the direct-connection type threaded joint has excellent external sealing performance. Moreover, the inner sealing portion and the outer sealing portion are respectively located on both sides of the threaded portion, which can prevent external media from entering the threaded part and causing stress corrosion. The internal and external double seals enable the internal and external sealing performance of the direct-connection type threaded joint to reach 100% of the pipe body. On the other hand, when the user screws the internal threaded joint 2 and the external threaded joint 1 together according to the specified make-up torque during use, the first outer shoulder 10 and the second outer shoulder 20 come into contact, while there is a gap between the first inner shoulder 15 and the second inner shoulder 25. The gap between the first inner shoulder 15 and the second inner shoulder 25 can provide a certain amount of compression space in the axial direction of the direct-connection type threaded joint. When the direct-connection type threaded joint bears a large compression load, both the first outer shoulder 10 and the second outer shoulder 20 and the first inner shoulder 15 and the second inner shoulder 25 come into contact, enabling the compression performance of the direct-connection type threaded joint to reach 100% of the joint connection strength. This not only greatly facilitates the use in the oilfield site but also can avoid the problem that one shoulder experiences excessive yield due to the low machining accuracy of the direct-connection type threaded joint. Furthermore, by providing a second groove 22 between the second outer sealing surface 21 and the second thread 27, not only can the axial stiffness of the second nose end 26 of the internal threaded joint 2 be reduced, but also the stress can be released. By providing a first groove 13 between the first thread 17 and the first inner sealing surface 14, not only can the axial stiffness of the first nose end 16 of the external threaded joint 1 be reduced, but also the stress can be released. Thus, the anti-compression performance of the direct-connection type threaded joint can be further improved. In this way, not only can the stress level at the nose end be reduced, but also the complex transition surfaces between the outer seal and the outer shoulder and between the inner sealing surface and the inner shoulder can be avoided to reduce the machining difficulty, thereby improving the machining efficiency. In summary, the direct-connection type threaded joint of the present invention not only has excellent external pressure sealing performance and anti-compression performance and can be used in complex well conditions with a small wellbore, a large required annulus clearance, and strict requirements for external pressure performance and anti-compression performance, but also can reduce the stress level at the nose end and improve the machining efficiency.

[0039] Furthermore, a first groove 13 is provided between the first thread 17 and the first inner sealing surface 14, which not only facilitates tool withdrawal during machining but also has the function of storing excess thread compound. A second groove 22 is provided between the second outer sealing surface 21 and the second thread 27, which not only facilitates tool withdrawal during machining but also has the function of storing excess thread compound.

[0040] It should be noted that in the embodiments of the present utility model, from the outside to the inside refers to the direction from the pipe body of the external thread joint 1 to the pipe end, that is, the direction from the pipe end of the internal thread joint 2 to the pipe body, which means Figure 1 from the left side to the right side in

[0041] As Figure 9 shown, in one embodiment, the first inner sealing surface 14 and the first thread 17 may not be provided with the first groove 13 either.

[0042] As Figure 8 shown, in one embodiment, the second outer sealing surface 21 and the second thread 27 may not be provided with the second groove 22 either.

[0043] It should be noted that as Figure 6 shown, the first nose end 16 refers to the pipe end of the external thread joint 1, and the second nose end 26 refers to the pipe end of the internal thread joint 2.

[0044] It should be noted that the direct-connection type thread joint in the embodiments of the present utility model is formed by screwing and combining the external thread joint 1 and the internal thread joint 2. The external thread joint 1 is processed on the outer surface of the pipe, and the internal thread joint 2 is processed on the inner surface of the pipe.

[0045] As Figure 4 and Figure 6 shown, in the embodiments of the present utility model, there is a distance L between the midpoint of the first outer sealing surface 12 and the first outer shoulder 10 10 , and the distance L 10 and the length L of the second outer sealing surface 21 20 satisfy the relationship: L 10 / L 20 = 0.3 to 1.2; and / or, the length L of the first outer sealing surface 12 11 and the length L of the second outer sealing surface 21 20 satisfy the relationship: L 11 / L 20 = 0.15 to 1.

[0046] The above parameter settings can improve the stiffness of the outer sealing part, so that the first outer sealing surface 12 and the second outer sealing surface 21 can maintain stable and tight contact fit, thereby enabling the direct-connection type thread joint to have excellent outer sealing performance; at the same time, combined with the setting of the first outer shoulder 10, the direct-connection type thread joint can have excellent compression resistance.

[0047] Specifically, in the embodiments of the present utility model, the smaller the above L 10 / L 20 value, the closer the first outer sealing surface 12 is to the pipe end of the internal thread joint 2, which will cause the first outer sealing surface 12 to be affected by the diameter expansion of the pipe end of the internal thread joint 2, thereby affecting the sealing performance; L10 / L 20 The larger the value, the more inclined the contact state between the first outer sealing surface 12 and the second outer sealing surface 21 is to separate under the action of external pressure, thus affecting the sealing performance. Therefore, L 10 / L 20 The preferred value range of the value is 0.5 ≤ L 10 / L 20 ≤ 0.9.

[0048] Specifically, in the embodiments of the present invention, the above L 11 / L 20 If the value is too small, the outer sealing contact length will be too short, resulting in too high an outer sealing contact pressure, and further causing the phenomenon of sticking of the sealing surface; L 11 / L 20 If the value is too large, the outer sealing contact length will be too large, resulting in too low an outer sealing contact pressure, and further causing the sealing effect to deteriorate. Therefore, L 11 / L 20 The range is preferably 0.2 ≤ L 11 / L 20 ≤ 0.5.

[0049] As Figure 5 and Figure 7 shown, in the embodiments of the present invention, there is a distance L 22 between the midpoint of the second inner sealing surface 23 and the second inner shoulder 25, and the distance L 22 and the length L 12 of the first inner sealing surface 14 satisfy the relationship: L 22 / L 12 = 0.3 to 1.2; and / or, the length L 21 of the second inner sealing surface 23 and the length L 12 of the first inner sealing surface 14 satisfy the relationship: L 21 / L 12 = 0.15 to 1.

[0050] The above parameter settings can improve the stiffness of the inner sealing part, so that the second inner sealing surface 23 and the first inner sealing surface 14 can maintain stable and close contact fit, thereby enabling the direct-connection type threaded joint to have excellent inner sealing performance; at the same time, combined with the setting of the second inner shoulder 25, the direct-connection type threaded joint can have excellent compression resistance.

[0051] Specifically, in the embodiments of the present invention, the above L 22 / L 12The smaller the value is, the closer the second inner sealing surface 23 is to the second inner shoulder 25. Then, the sealing effect between the second inner sealing surface 23 and the first inner sealing surface 14 will be affected by the force acting near the second inner shoulder 25 and also by the necking of the pipe end of the external thread joint 1, thus affecting the inner sealing performance; L 22 / L 12 The larger the value is, under the action of internal pressure, the contact state between the first inner sealing surface 14 of the external thread joint 1 and the second inner sealing surface 23 of the internal thread joint 2 tends to separate, thus affecting the inner sealing performance. Therefore, L 22 / L 12 The range of L 22 / L 12 is preferably 0.5 ≤ L

[0052] Specifically, in the embodiment of the present invention, for the above L 21 / L 12 the smaller the value is, the shorter the inner sealing contact length will be, resulting in an excessive inner sealing contact pressure, and further leading to the phenomenon of galling on the sealing surface; while for L 21 / L 12 the larger the value is, the longer the inner sealing contact length will be, resulting in a too low inner sealing contact pressure, and further leading to a poor sealing effect. Therefore, the range of L 21 / L 12 is preferably 0.2 ≤ L 21 / L 12 ≤ 0.5.

[0053] It should be noted that in the embodiment of the present invention, on the axis of the direct-connection type thread joint, the distances from the midpoint of the first outer sealing surface 12 to both ends of the first outer sealing surface 12 are equal, and the distance between the midpoint of the first outer sealing surface 12 and the first outer shoulder 10 refers to the distance between the intersection point of the first outer shoulder 10 and the first connection surface 11 and the midpoint of the first outer sealing surface 12 in the above axial direction; the midpoint of the second inner sealing surface 23 and the distance between the midpoint of the second inner sealing surface 23 and the second inner shoulder 25 are set in the same way, which will not be elaborated here.

[0054] It should be noted that in the embodiment of the present invention, the length L 11 the length L 20 the length L 21 and the length L 12 all refer to the length of the corresponding sealing surface on the axis of the direct-connection type thread joint.

[0055] Such as Figure 4 and Figure 6As shown in the figure, in the embodiment of the present utility model, the first outer shoulder 10 is inclined with respect to the axis L, and along the axis L, in the direction from the outside to the inside, the distance between the first outer shoulder 10 and the axis L gradually increases; the second outer shoulder 20 is inclined with respect to the axis L, and along the axis L, in the direction from the outside to the inside, the distance between the second outer shoulder 20 and the axis L gradually increases, and the first outer shoulder 10 and the second outer shoulder 20 are in interference fit. In this way, it can play a role in screwing connection positioning and anti-compression.

[0056] In one embodiment, the first outer shoulder 10 and the second outer shoulder 20 are in contact fit, which plays a role in screwing connection positioning and anti-compression.

[0057] As Figure 4 and Figure 6 shown in the figure, in the embodiment of the present utility model, there is an angle α1 between the first outer shoulder 10 and the cross-section of the external thread joint 1, and the range of the angle α1 is: 0° ≤ α1 ≤ 15°, there is an angle β1 between the second outer shoulder 20 and the cross-section of the internal thread joint 2, and the range of the angle β1 is: 0° ≤ β1 ≤ 15°, and it satisfies: 0° ≤ α1 - β1 ≤ 1°.

[0058] By setting the above parameters, it is possible to compensate for the influence that the interference amount between the first outer shoulder 10 and the second outer shoulder 20 is uneven on the entire contact surface due to the diameter expansion of the internal thread joint 2 from the inside to the outside. Thus, after the first outer shoulder 10 and the second outer shoulder 20 are in interference contact, the first outer shoulder 10 and the second outer shoulder 20 can be uniformly stressed, and further, the direct connection type threaded joint has good compression performance, and at the same time, it is beneficial to the good contact between the second outer sealing surface 21 and the first outer sealing surface 12.

[0059] As Figure 4 and Figure 6 shown in the figure, in the embodiment of the present utility model, the first outer sealing surface 12 is inclined with respect to the axis L, and along the axis L, in the direction from the outside to the inside, the distance between the first outer sealing surface 12 and the axis L gradually decreases; the second outer sealing surface 21 is inclined with respect to the axis L, and along the axis L, in the direction from the outside to the inside, the distance between the second outer sealing surface 21 and the axis L gradually decreases, and the first outer sealing surface 12 and the second outer sealing surface 21 are in interference fit. In this way, a sealing effect can be produced.

[0060] As Figure 4 and Figure 6 shown in the figure, in the embodiment of the present utility model, there is an angle α2 between the first outer sealing surface 12 and the axis L, and the range of the angle α2 is: 3.50° ≤ α2 ≤ 9.90°, there is an angle β2 between the second outer sealing surface 21 and the axis L, and the range of the angle β2 is: 3.50° ≤ β2 ≤ 9.90°, and it satisfies: 0° ≤ α2 - β2 ≤ 1.5°.

[0061] By setting the above parameters, the influence of the reduced sealing contact pressure on the side of the pipe end of the internal thread joint 2 caused by the pipe end expansion of the internal thread joint 2 and the external pressure can be compensated, so as to achieve a uniform distribution of the sealing contact pressure and realize a stable sealing effect. In this way, the direct-connected thread joint can have an excellent sealing distribution state and good anti-galling performance of the sealing surface.

[0062] As Figure 4 shown, in the embodiment of the present utility model, the external thread joint 1 is further provided with a first connection surface 11, the first connection surface 11 is connected between the first external sealing surface 12 and the first external shoulder 10, the first connection surface 11 and the first external sealing surface 12 are arranged at an angle, and the first connection surface 11 is lower than or flush with one end of the first external sealing surface 12 facing the first external shoulder 10. In this way, it is possible to avoid reducing the thickness of the first external shoulder 10 in the radial direction of the direct-connected thread joint, thereby avoiding affecting the sealing effect.

[0063] As Figure 10 shown, in one embodiment, along the axis L, the first external sealing surface 12 extends from the first external shoulder 10 to the first thread 17.

[0064] As Figure 5 and Figure 7 shown, in the embodiment of the present utility model, the first internal sealing surface 14 is inclined with respect to the axis L. Along the axis L, in the direction from the outside to the inside, the distance between the first internal sealing surface 14 and the axis L gradually decreases; the second internal sealing surface 23 is inclined with respect to the axis L. Along the axis L, in the direction from the outside to the inside, the distance between the second internal sealing surface 23 and the axis L gradually decreases, and the first internal sealing surface 14 and the second internal sealing surface 23 are in interference fit. In this way, a sealing effect can be produced.

[0065] As Figure 5 and Figure 7 shown, in the embodiment of the present utility model, the first internal sealing surface 14 and the axis L have an angle α3, and the range of the angle α3 is: 3.50° ≤ α3 ≤ 9.90°. The second internal sealing surface 23 and the axis L have an angle β3, and the range of the angle β3 is: 3.50° ≤ β3 ≤ 9.90°, and it satisfies: 0° ≤ β3 - α3 ≤ 1.5°.

[0066] By setting the above parameters, the influence of the reduced sealing contact pressure on the side of the pipe end of the external thread joint 1 caused by the pipe end reduction of the external thread joint 1 and the internal pressure can be compensated, so as to achieve a uniform distribution of the sealing contact pressure and realize a stable sealing effect. Furthermore, the direct-connected thread joint can have an excellent sealing distribution state and good anti-galling performance of the sealing surface.

[0067] As Figure 7As shown, in the embodiment of the present utility model, a second connection surface 24 is further provided on the internal thread joint 2. The second connection surface 24 is connected between the second internal sealing surface 23 and the second internal shoulder 25. The second connection surface 24 is arranged at an angle with the second internal sealing surface 23, and the second connection surface 24 is lower than or flush with one end of the second internal sealing surface 23 facing the second internal shoulder 25. In this way, it is possible to avoid reducing the thickness of the second internal shoulder 25 in the radial direction of the direct-connection type thread joint, thereby avoiding affecting the sealing effect.

[0068] As Figure 11 shown, in one embodiment, along the axis L, from the outside to the inside, the second internal sealing surface 23 extends from the second thread 27 to the second internal shoulder 25.

[0069] As Figure 5 shown, in the embodiment of the present utility model, the first internal shoulder 15 is inclined relative to the axis L. Along the axis L, in the direction from the outside to the inside, the distance between the first internal shoulder 15 and the axis L gradually increases; the second internal shoulder 25 is inclined relative to the axis L. Along the axis L, in the direction from the outside to the inside, the distance between the second internal shoulder 25 and the axis L gradually increases; there is an angle α4 between the first internal shoulder 15 and the cross-section of the external thread joint 1, and the range of the angle α4 is: 0° ≤ α4 ≤ 15°. There is an angle β4 between the second internal shoulder 25 and the cross-section of the internal thread joint 2, and the range of the angle β4 is: 0° ≤ β4 ≤ 15°.

[0070] Through the above settings, when the direct-connection type thread joint bears a large compressive load, contact will occur between the first internal shoulder 15 and the second internal shoulder 25, that is, the first internal shoulder 15 and the second internal shoulder 25 are in contact and cooperate. The setting of the above parameters can make the compression performance of the direct-connection type thread joint reach 100% of the joint connection strength.

[0071] Preferably, in the embodiment of the present utility model, there is a gap between the first internal shoulder 15 and the second internal shoulder 25. When the direct-connection type thread joint bears a large compressive load, contact will occur between the first internal shoulder 15 and the second internal shoulder 25 to achieve a further anti-over-twisting effect.

[0072] In one embodiment, the first internal shoulder 15 and the second internal shoulder 25 can also be in contact and cooperate.

[0073] Preferably, in the embodiment of the present utility model, the length L 21 of the second internal sealing surface 23 ranges from: 2 mm ≤ L 21 ≤ 5 mm. In this way, a relatively optimal sealing contact pressure and sealing contact length can be achieved comprehensively.

[0074] Preferably, in the embodiment of the present utility model, the length L 11The range of L is: 2mm ≤ L 11 ≤ 5mm. In this way, a relatively optimal comprehensive sealing contact pressure and sealing contact length can be achieved.

[0075] It should be noted that the direct-connected threaded joint of the present utility model has excellent external pressure sealing performance, internal pressure sealing performance and compression performance under various combined loads; this direct-connected threaded joint is particularly suitable for complex well conditions with demanding external pressure requirements and relatively high anti-compression requirements.

[0076] Compared with the prior art, the present patented technology has significant progress, specifically manifested in: 1. The use of an inner sealing part and an outer sealing part to achieve independent internal and external double sealing, making the sealing more reliable; 2. Based on the finite element analysis of different operating conditions, by adopting the sealing surface structure parameters of this design, the sealing integrity and sealing robustness of the threaded joint are greatly improved; 3. Further limitation of the angle relationship of the outer sealing surface, the angle relationship of the inner sealing surface, and the angle relationship of the shoulder surfaces (the first outer shoulder 10 and the second outer shoulder 20; the first inner shoulder 15 and the second inner shoulder 25) compensates for the influence caused by uneven pressure at the contact part, achieving a robust sealing effect and good compression performance. 4. A second groove 22 is machined between the second outer sealing surface 21 and the second thread 27, which is convenient for tool withdrawal during machining, and at the same time has the functions of storing excess thread compound, releasing stress, and reducing the axial stiffness of the nose end of the internal threaded joint 2, which can further improve the anti-compression performance of this direct-connected threaded joint. 5. A first groove 13 is provided between the first thread 17 and the first inner sealing surface 14, which serves to withdraw the tool during machining, store excess thread compound, release stress, and reduce the stress level of the nose end of the external threaded joint 1.

[0077] An embodiment of the present utility model adopts a direct-connected casing with a specification of φ206.38mm × 17.25mm and a steel grade of 140V. The geometric parameters of the threaded joint are: L 10 / L 20 = 0.6, L 11 / L 20 = 0.35, L 22 / L 12 = 0.7, L 21 / L 12 = 0.35, α1 = 8.5°, β1 = 8°, α2 = 7.1°, β2 = 6.7°, α3 = 6.7°, β3 = 7.1°, α4 = 8°, β4 = 8.5°, L 21 = 4mm, L 11= 4 mm. The connection strength of this direct-connected threaded joint reaches 6641 kN, the compression strength reaches 6641 kN, the internal pressure sealing performance reaches 65 Mpa, the external pressure performance reaches 37 Mpa, the bending resistance reaches 20° / 30 m, and it meets the requirement of no sticking during 3 make-and-break operations. This casing threaded joint has excellent internal pressure sealing performance, external pressure sealing performance and compression performance.

[0078] Another embodiment of the present invention uses a direct-connected tubing with a specification of 108×9 mm and a steel grade of P110. The geometric parameters of the threaded joint are: L 10 / L 20 = 0.65, L 11 / L 20 = 0.3, L22 / L12 = 0.75, L 21 / L 12 = 0.3, α1 = 8.5°, β1 = 8°, α2 = 7.1°, β2 = 6.7°, α3 = 6.7°, β3 = 7.1°, α4 = 8°, β4 = 8.5°, L 21 = 3.50 mm, L 11 = 3.5 mm. The connection strength of this direct-connected tubing threaded joint reaches 1168 kN, the compression strength reaches 1168 kN, the internal pressure sealing performance reaches 111 Mpa, the external pressure sealing performance reaches 116 Mpa, the bending resistance reaches 46° / 30 m, and it meets the requirement of no sticking during 10 make-and-break operations. This tubing threaded joint has excellent internal pressure sealing performance, external pressure sealing performance and compression performance.

[0079] From the above description, it can be seen that the above embodiments of the present utility model achieve the following technical effects: On the one hand, the first inner sealing surface and the second inner sealing surface that are hermetically fitted form an inner sealing portion, the first outer sealing surface and the second outer sealing surface that are hermetically fitted form an outer sealing portion, and the first thread and the second thread are connected to form a threaded portion. By adopting an independent inner sealing portion, the direct-connected threaded joint has excellent internal pressure sealing performance. At the same time, by adopting an independent outer sealing portion, the direct-connected threaded joint has excellent external sealing performance. Moreover, the inner sealing portion and the outer sealing portion are respectively located on both sides of the threaded portion, which can prevent external media from entering the threaded part and causing stress corrosion. The double internal and external seals enable the internal and external sealing performance of the direct-connected threaded joint to reach 100% of the pipe body. On the other hand, when the user screws the internal threaded joint and the external threaded joint together according to the specified make-up torque during use, the first outer shoulder and the second outer shoulder come into contact, while there is a gap between the first inner shoulder and the second inner shoulder. The gap between the first inner shoulder and the second inner shoulder can provide a certain amount of compression space in the axial direction of the direct-connected threaded joint. When the direct-connected threaded joint bears a large compression load, contact occurs between the first outer shoulder and the second outer shoulder as well as between the first inner shoulder and the second inner shoulder, enabling the compression performance of the direct-connected threaded joint to reach 100% of the joint connection strength. This not only greatly facilitates the use in the oilfield field but also can avoid the problem of excessive yield due to the low machining accuracy of the direct-connected threaded joint causing one of the shoulders to be stressed. On the further hand, by providing a second groove between the second outer sealing surface and the second thread, not only can the axial stiffness of the second nose end of the internal threaded joint be reduced, but also the stress release function can be achieved. By providing a first groove between the first thread and the first inner sealing surface, not only can the axial stiffness of the first nose end of the external threaded joint be reduced, but also the stress release function can be achieved. Thereby, the compression resistance performance of the direct-connected threaded joint can be further improved. In this way, not only can the stress level at the nose end be reduced, but also the complex transition surfaces between the external seal and the outer shoulder as well as between the inner sealing surface and the inner shoulder can be avoided to reduce the machining difficulty, thereby improving the machining efficiency. In summary, the direct-connected threaded joint of the present utility model not only has excellent external pressure sealing performance and compression resistance performance, can be used in complex well conditions with a small borehole, a large annular clearance requirement, and strict requirements for external pressure performance and compression resistance performance, but also can reduce the stress level at the nose end and improve the machining efficiency.

[0080] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. For those skilled in the art, the present utility model can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A direct-connection threaded joint, characterized in that: The straight-through threaded joint has an axis (L), and the straight-through threaded joint comprises: Internal thread connector (2); An external threaded joint (1), at least a portion of the external threaded joint (1) extends into the internal threaded joint (2), and along the axis (L), the external threaded joint (1) is provided with a first external shoulder (10), a first external sealing surface (12), a first thread (17), a first groove (13), a first internal sealing surface (14) and a first internal shoulder (15) in sequence from the outside to the inside, and the internal threaded joint (2) is provided with a second external shoulder (20), a second external sealing surface (21), a second groove (22), a second thread (27), a second internal sealing surface (23) and a second internal shoulder (25) in sequence from the outside to the inside; The external thread joint (1) and the internal thread joint (2) are connected via the first thread (17) and the second thread (27), and the first external sealing surface (12) and the second external sealing surface (21) are sealed together, the first internal sealing surface (14) and the second internal sealing surface (23) are sealed together, and when the first external shoulder (10) and the second external shoulder (20) are in contact, the first internal shoulder (15) and the second internal shoulder (25) are clearance-fitted together.

2. The direct-connection threaded joint according to claim 1, characterized in that: There is a distance L between the midpoint of the first outer sealing surface (12) and the first outer shoulder (10). 10 , the distance L 10 The length L of the second outer sealing surface (21) 20 Satisfaction relationship: L 10 / L 20 =0.3~1.2; and / or, The length L of the first outer sealing surface (12) 11 The length L of the second outer sealing surface (21) 20 Satisfaction relationship: L 11 / L 20 0.15 to 1.

3. The direct-connection threaded joint according to claim 1, characterized in that: There is a distance L between the midpoint of the second inner sealing surface (23) and the second inner shoulder (25). 22 , the distance L 22 The length L of the first inner sealing surface (14) 12 Satisfaction relationship: L 22 / L 12 =0.3~1.2; and / or, The length L of the second inner sealing surface (23) 21 The length L of the first inner sealing surface (14) 12 Satisfaction relationship: L 21 / L 12 0.15 to 1.

4. The straight-connection threaded joint according to any one of claims 1 to 3, characterized in that: The first outer shoulder (10) is arranged obliquely relative to the axis (L), and along the axis (L), from the outer side to the inner side, the distance between the first outer shoulder (10) and the axis (L) gradually increases; The second outer shoulder (20) is inclined relative to the axis (L), and along the axis (L), from the outer side to the inner side, the distance between the second outer shoulder (20) and the axis (L) gradually increases, and the first outer shoulder (10) and the second outer shoulder (20) are interference fit.

5. The direct-connection threaded joint according to claim 4, characterized in that: An angle α1 is formed between the first external shoulder (10) and the cross section of the external threaded joint (1), and the range of the angle α1 is: 0°≤α1≤15°; an angle β1 is formed between the second external shoulder (20) and the cross section of the internal threaded joint (2), and the range of the angle β1 is: 0°≤β1≤15°, and the condition is satisfied: 0°≤α1-β1≤1°.

6. The straight-connection threaded joint according to any one of claims 1 to 3, characterized in that: The first outer sealing surface (12) is arranged to be inclined relative to the axis (L), and along the axis (L), from the outer side to the inner side, the distance between the first outer sealing surface (12) and the axis (L) gradually decreases; The second outer sealing surface (21) is arranged to be inclined relative to the axis (L); along the axis (L), in the direction from the outer side to the inner side, the distance between the second outer sealing surface (21) and the axis (L) gradually decreases; the first outer sealing surface (12) and the second outer sealing surface (21) are interference fit.

7. The direct-connection threaded joint according to claim 6, characterized in that: An angle α2 is formed between the first outer sealing surface (12) and the axis (L), and the range of the angle α2 is: 3.50°≤α2≤9.90°; an angle β2 is formed between the second outer sealing surface (21) and the axis (L), and the range of the angle β2 is: 3.50°≤β2≤9.90°, and the condition is satisfied: 0°≤α2-β2≤1.5°.

8. The direct-connection threaded joint according to claim 6, characterized in that: The external threaded joint (1) is further provided with a first connecting surface (11), the first connecting surface (11) being connected between the first external sealing surface (12) and the first external shoulder (10), the first connecting surface (11) being arranged at an angle to the first external sealing surface (12), and the first connecting surface (11) being lower than or flush with an end of the first external sealing surface (12) facing the first external shoulder (10); or, Along the axis (L), the first outer sealing surface (12) extends from the first outer shoulder (10) to the first thread (17).

9. The straight-connection threaded joint according to any one of claims 1 to 3, characterized in that: The first inner sealing surface (14) is arranged to be inclined relative to the axis (L), and along the axis (L), from the outer side to the inner side, the distance between the first inner sealing surface (14) and the axis (L) gradually decreases; The second inner sealing surface (23) is arranged to be inclined relative to the axis (L); along the axis (L), in the direction from the outer side to the inner side, the distance between the second inner sealing surface (23) and the axis (L) gradually decreases; the first inner sealing surface (14) and the second inner sealing surface (23) are interference fit.

10. The direct-connection threaded joint according to claim 9, characterized in that: An angle α3 is formed between the first inner sealing surface (14) and the axis (L), and the range of the angle α3 is: 3.50°≤α3≤9.90°; an angle β3 is formed between the second inner sealing surface (23) and the axis (L), and the range of the angle β3 is: 3.50°≤β3≤9.90°, and the condition is satisfied: 0°≤β3-α3≤1.5°.

11. The direct-connection threaded joint according to claim 9, characterized in that: The internal thread joint (2) is further provided with a second connection surface (24), the second connection surface (24) being connected between the second inner sealing surface (23) and the second inner shoulder (25), the second connection surface (24) being arranged at an angle with the second inner sealing surface (23), and the second connection surface (24) being lower than or flush with an end of the second inner sealing surface (23) facing the second inner shoulder (25); or, Along the axis (L), from the outer side to the inner side, the second inner sealing surface (23) extends from the second thread (27) to the second inner shoulder (25).

12. The straight-connection threaded joint according to any one of claims 1 to 3, characterized in that: The first inner shoulder (15) is arranged obliquely relative to the axis (L), and along the axis (L), from the outer side to the inner side, the distance between the first inner shoulder (15) and the axis (L) gradually increases; The second inner shoulder (25) is arranged obliquely relative to the axis (L), and along the axis (L), from the outer side to the inner side, the distance between the second inner shoulder (25) and the axis (L) gradually increases; An angle α4 is formed between the first inner shoulder (15) and the cross section of the external threaded joint (1), and the range of the angle α4 is: 0°≤α4≤15°; an angle β4 is formed between the second inner shoulder (25) and the cross section of the internal threaded joint (2), and the range of the angle β4 is: 0°≤β4≤15°.

13. The straight-connection threaded joint according to any one of claims 1 to 3, characterized in that: The length L of the second inner sealing surface (23) 21 The range is: 2mm≤L 21 ≤5mm; and / or, The length L of the first outer sealing surface (12) 11 The range is: 2mm≤L 11 ≤5mm.

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