CN220705652U - Casing threaded joint - Google Patents

Abstract

The utility model provides a threaded sleeve joint. The box nipple includes: an internally threaded joint; the external threaded joint is in threaded connection with the internal threaded joint, and a threaded part b and a first stress relief part a arranged on one side of the threaded part b are arranged between the external threaded joint and the internal threaded joint along the axial direction of the sleeve threaded joint; the external threaded connector is provided with a first external thread and a second external thread, the internal threaded connector is provided with a first internal thread and a second internal thread, the second external thread and the second internal thread are matched to form a threaded part b, a first stress reduction part a is arranged between the first external thread and the first internal thread, and the first stress reduction part a comprises a first groove arranged on the tooth top of the first internal thread. The technical scheme of the utility model can reduce stress concentration between the external threaded joint and the internal threaded joint, thereby having better fatigue resistance.

Description

Casing threaded joint

Technical Field

The utility model relates to the technical field of petroleum pipes, in particular to a sleeve threaded joint.

Background

In the application environment of the oil casing threaded joint, the oil casing threaded joint is required to bear cyclic stretching compression dynamic load due to frequent high-low temperature alternation of the marine casing and the land high-temperature oil-gas well, namely, the casing threaded joint has good connection strength performance and certain fatigue resistance.

At present, the existing standard API 5B sleeve joint comprises a pipe body and a coupling, wherein external threads are formed at the end part of the pipe body, internal threads are formed at the end part of the coupling, and the pipe body and the coupling are screwed together so as to realize threaded connection. Because the interference of the API sleeve joint is larger, and the end effect of the two ends of the pipe body and the coupling is added, the connection part between the pipe body and the coupling has larger stress concentration, and the standard API sleeve has no fatigue resistance.

Disclosure of Invention

The utility model mainly aims to provide a sleeve threaded joint, which can solve the problems that the existing sleeve threaded joint has larger stress concentration and further does not have fatigue resistance.

To achieve the above object, according to an aspect of the present utility model, there is provided a box thread joint comprising: an internally threaded joint; the external threaded joint is in threaded connection with the internal threaded joint, and a threaded part b and a first stress relief part a arranged on one side of the threaded part b are arranged between the external threaded joint and the internal threaded joint along the axial direction of the sleeve threaded joint; the external threaded connector is provided with a first external thread and a second external thread, the internal threaded connector is provided with a first internal thread and a second internal thread, the second external thread and the second internal thread are matched to form a threaded part b, a first stress reduction part a is arranged between the first external thread and the first internal thread, and the first stress reduction part a comprises a first groove arranged on the tooth top of the first internal thread.

Further, along the axial direction of the casing threaded joint, from the outer side to the inner side, the first stress relief portion a and the threaded portion b are sequentially arranged, the first internal thread comprises a plurality of first protrusions arranged at intervals, and first grooves are formed in tooth tops of the first protrusions.

Further, an included angle alpha 1 is formed between the connecting line of the buses of the plurality of first grooves and the axis of the first internal thread, and the included angle alpha 1 ranges from 3 degrees to 6 degrees.

Further, from the outside to the inside, the height dimensions of the plurality of first grooves gradually decrease, and the maximum height H2 in the plurality of first grooves has the following relationship with the profile height H1 of the first internal thread: H2/H1 is more than or equal to 0.5 and less than or equal to 0.9.

Further, the box thread joint further includes a second stress relief portion c provided between the pin thread joint and the box thread joint, and the first stress relief portion a, the thread portion b, and the second stress relief portion c are provided in this order from the outside to the inside in the axial direction of the box thread joint.

Further, a third external thread is further formed on the external thread connector, a third internal thread is further formed on the internal thread connector, and the second stress relief portion c comprises a second groove arranged on the tooth top of the third internal thread.

Further, the third internal thread comprises a plurality of second bulges arranged at intervals, the tooth tops of the second bulges are provided with second grooves, an included angle alpha 2 is formed between the connecting buses of the second grooves and the axis of the third internal thread, and the included angle alpha 2 ranges from 1 degree to 3 degrees.

Further, from the outside to the inside, the height dimensions of the plurality of second grooves gradually increase, and the maximum height H3 of the plurality of second grooves and the tooth form height H4 of the third internal thread have the following relationship: H3/H4 is more than or equal to 0.2 and less than or equal to 0.4.

Further, the second groove is triangular or trapezoidal.

Further, the first groove is triangular or trapezoidal.

By applying the technical scheme of the utility model, the first stress reducing part a is positioned at the large end or the small end of the threaded sleeve joint, and the interference between the external threaded joint and the internal threaded joint is larger when the threaded joint is in threaded connection, so that larger stress concentration exists at the large end and the small end of the threaded sleeve joint, and the stress concentration is further increased after the threaded sleeve joint bears tensile and compressive loads. Through setting up first stress reduction portion a, sleeve pipe screwed joint is after bearing tensile and compressive load, and first recess makes sleeve pipe screwed joint's major end or the screw thread rigidity of tip reduce, and too high stress distributes screw thread portion b to make the whole stress evenly distributed of joint, sleeve pipe screwed joint has good fatigue resistance. And the sleeve threaded joint disclosed by the utility model is simple in processing technology, and can be used as working conditions with high requirements on fatigue performance joints, such as marine drilling risers, surface layer sleeves, riser pipes, risers and the like. Compared with the existing sleeve threaded joint, the sleeve threaded joint has the advantages of being even in stress distribution, capable of reducing stress concentration, good in fatigue resistance, simple and convenient to process and the like.

Drawings

The accompanying drawings, which are included to provide a further understanding of the utility model and are incorporated in and constitute a part of this specification, illustrate embodiments of the utility model and together with the description serve to explain the utility model. Attached at

In the figure:

FIG. 1 shows a schematic structural view of a box thread joint according to an embodiment of the present utility model;

fig. 2 shows a schematic view of the internal thread joint of the box thread joint of fig. 1;

fig. 3 shows a schematic view of the structure of an external threaded joint of the box threaded joint of fig. 1;

fig. 4 shows an enlarged view of the female joint of fig. 2 at m;

fig. 5 shows an enlarged view of the female connector of fig. 2 at n;

fig. 6 shows an enlarged view at N1 of the internally threaded joint of fig. 4;

fig. 7 shows an enlarged view at N2 of the internally threaded joint of fig. 5.

Wherein the above figures include the following reference numerals:

1. an external threaded joint; 11. a first external thread; 12. a second external thread; 13. a third external thread; 2. an internally threaded joint; 21. a first internal thread; 22. a second internal thread; 23. a third internal thread; 3. a first groove; 4. and a second groove.

Detailed Description

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

The casing threaded joint is mainly used for low-stress threaded joints on casings and couplings in the petroleum industry, and belongs to the technical field of petroleum pipes. Of course, the sleeve threaded joint can also be used as a joint with high fatigue performance such as marine drilling risers, surface sleeves, riser pipes, risers and the like.

It should be noted that, in one prior art known to the inventor, chinese patent CN210888834U discloses a "fatigue-resistant tooth form of an oil casing threaded joint", which provides a fatigue-resistant tooth form of an oil casing threaded joint, including external thread teeth and internal thread teeth; after the external thread teeth and the internal thread teeth are matched, gaps are reserved between tooth tops and tooth bottoms of the external thread teeth and the internal thread teeth so as to form an anti-fatigue groove structure. However, the tooth form has a complex structure, low processing efficiency, difficult detection and no interchange with standard API sleeve joints.

Therefore, in order to solve the technical problems, the utility model provides the threaded sleeve joint which has a simple structure, is convenient to process and can reduce stress concentration.

Referring to fig. 1 to 5, the present utility model provides a box thread joint comprising: an internally threaded joint 2; an external threaded joint 1 which is in threaded connection with the internal threaded joint 2, and a threaded portion b and a first stress relief portion a provided on one side of the threaded portion b are provided between the external threaded joint 1 and the internal threaded joint 2 in the axial direction of the box threaded joint; the external threaded joint 1 is provided with a first external thread 11 and a second external thread 12, the internal threaded joint 2 is provided with a first internal thread 21 and a second internal thread 22, the second external thread 12 and the second internal thread 22 are in threaded fit to form a threaded part b, a first stress relief part a is arranged between the first external thread 11 and the first internal thread 21, and the first stress relief part a comprises a first groove 3 arranged on the tooth crest of the first internal thread 21.

The casing thread joint is formed by screwing a pipe body and a coupling, wherein an external thread joint is processed at the end part of the pipe body, an internal thread joint is processed at the end part of the coupling, the casing thread joint is improved by an API buttress thread, and a user can fasten the casing thread joint according to the API thread joint in use.

Through the above arrangement, the first stress relief portion a is located at the large end or the small end of the threaded sleeve joint, and because the interference between the external threaded joint 1 and the internal threaded joint 2 is large during threaded connection, the large end and the small end of the threaded sleeve joint have large stress concentration, and the stress concentration is further aggravated after bearing tensile and compressive loads. Through setting up first stress reduction portion a, sleeve pipe screwed joint is after bearing tensile and compressive load, and first recess 3 makes sleeve pipe screwed joint's the screw thread rigidity of big end or tip reduce, and too high stress distributes screw portion b to make joint overall stress evenly distributed, sleeve pipe screwed joint has good fatigue resistance. And the sleeve threaded joint disclosed by the utility model is simple in processing technology, and can be used as working conditions with high requirements on fatigue performance joints, such as marine drilling risers, surface layer sleeves, riser pipes, risers and the like. Compared with the existing sleeve threaded joint, the sleeve threaded joint has the advantages of being even in stress distribution, capable of reducing stress concentration, good in fatigue resistance, simple and convenient to process and the like.

As shown in fig. 1 to 5, in the embodiment of the present utility model, the first stress relief portion a and the threaded portion b are provided in this order from the outside to the inside in the axial direction of the box screw joint, and the first internal thread 21 includes a plurality of first protrusions provided at intervals, and each of the first protrusions has a first groove 3 provided at its tip.

Through the arrangement, the first grooves are formed in the tooth tops of the first protrusions, so that the first grooves 3 can play a role in stress reduction, stress between the internal thread connector and the external thread connector is uniformly distributed, and the sleeve thread connector has good fatigue resistance.

As shown in fig. 4, in the embodiment of the present utility model, an included angle α1 is formed between a line connecting the generatrixes of the plurality of first grooves 3 and the axis of the first internal thread 21, and the included angle α1 ranges from 3 ° to 6 °.

By the above arrangement, the first groove 3 can be ensured to function as a stress reducing effect and to facilitate processing.

As shown in fig. 6, in the embodiment of the present utility model, the height dimension of the plurality of first grooves 3 gradually decreases from the outside to the inside, and the maximum height H2 in the plurality of first grooves 3 has the following relationship with the thread height H1 of the first female screw 21: H2/H1 is more than or equal to 0.5 and less than or equal to 0.9.

By the above arrangement, the first groove 3 can be ensured to function as a stress reducing effect and to facilitate processing.

As shown in fig. 1 to 5, in the embodiment of the present utility model, the box thread joint further includes a second stress relief portion c provided between the pin thread joint 1 and the box thread joint 2, the first stress relief portion a, the thread portion b, and the second stress relief portion c being provided in this order from the outside to the inside in the axial direction of the box thread joint.

Through above-mentioned setting, through setting up first stress relief portion and second stress relief portion c, can play the effect that reduces the stress simultaneously in casing threaded joint's big end and tip to further avoid stress concentration, improve fatigue resistance.

As shown in fig. 1 to 5, in the embodiment of the present utility model, the external threaded joint 1 is further provided with a third external thread 13, the internal threaded joint 2 is further provided with a third internal thread 23, and the second stress relief portion c includes a second groove 4 provided at the crest of the third internal thread 23.

In the above technical scheme, the third internal thread 23 includes a plurality of second archs that the interval set up, and the second recess 4 has all been seted up to every bellied tooth top of second, and like this, a plurality of second recesses 4 homoenergetic plays the effect that reduces the stress to make the stress evenly distributed between internal thread joint and the external screw thread joint, sleeve pipe screwed joint has good fatigue resistance.

As shown in fig. 5, in the embodiment of the present utility model, an included angle α2 is formed between the connecting generatrix of the plurality of second grooves 4 and the axis of the third internal thread 23, and the included angle α2 ranges from 1 ° to 3 °.

By the above arrangement, the second groove 4 can be ensured to play a role of reducing stress, and processing is facilitated.

As shown in fig. 7, in the embodiment of the present utility model, the height dimension of the plurality of second grooves 4 is gradually increased from the outside to the inside, and the maximum height H3 of the plurality of second grooves 4 and the tooth form height H4 of the third female screw 23 have the following relationship: H3/H4 is more than or equal to 0.2 and less than or equal to 0.4.

The profile height H4 of the third female screw 23 is the same as the profile height H1 of the first female screw 21.

By the above arrangement, the second groove 4 can be ensured to play a role of reducing stress, and processing is facilitated.

As shown in the left-hand view of fig. 7, in one embodiment of the utility model, the second recess 4 is triangular.

As shown in the right-hand drawing of fig. 7, in one embodiment of the present utility model, the second groove 4 is trapezoidal.

As shown in the left-hand diagram of fig. 6, in an embodiment of the utility model, the first recess 3 is triangular.

As shown in the right-hand drawing of fig. 6, in the embodiment of the present utility model, the first groove 3 is trapezoidal.

In one application of the utility model, the external threaded joint adopts a phi 244.48 multiplied by 11.99mm specification sleeve, the steel grade is P110, the external diameter of the coupling is regulated by adopting an API standard, and the material performance meets the requirements of the API standard. The geometric parameters of the external thread joint and the internal thread joint are the same as those of the API standard buttress thread joint, and the difference is that: the first stress reducing part a is provided with a first groove 3, the second stress reducing part c is provided with a second groove 4, alpha 1 is 4.2 degrees, and alpha 2 is 1.5 degrees. The height relation between H2 and the thread tooth H1 is as follows: h2/h1=0.85. The height relation between H3 and the thread tooth H4 is as follows: h3/h4=0.3.

According to experiments, the stress concentration degree of the threaded sleeve joint is greatly reduced, the stress concentration coefficient is smaller than 2.0, the connection strength reaches 5313kN, the internal pressure air tightness reaches more than 65Mpa, the external pressure resistance reaches more than 37Mpa, the bending resistance reaches more than 20 degrees/30 m, and the requirement of 3 times of screwing-off and unhooking is met.

From the above description, it can be seen that the above-described embodiments of the present utility model achieve the following technical effects: through setting up first stress reduction portion a and second stress reduction portion c, sleeve pipe screwed joint is born tensile and compressive load after, and the screw thread rigidity of sleeve pipe screwed joint's big end and tip reduces, and too high stress distributes screw thread portion b to make the joint overall stress evenly distributed, sleeve pipe screwed joint has good fatigue resistance. And the sleeve threaded joint disclosed by the utility model is simple in processing technology, and can be used as working conditions with high requirements on fatigue performance joints, such as marine drilling risers, surface layer sleeves, riser pipes, risers and the like. Compared with the existing sleeve threaded joint, the sleeve threaded joint has the advantages of being even in stress distribution, capable of reducing stress concentration, good in fatigue resistance, simple and convenient to process and the like.

It will be apparent that the embodiments described above are merely some, but not all, embodiments of the utility model. All other embodiments, which can be made by those skilled in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular is also intended to include the plural unless the context clearly indicates otherwise, and furthermore, it is to be understood that the terms "comprises" and/or "comprising" when used in this specification are taken to specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof.

The above description is only of the preferred embodiments of the present utility model and is not intended to limit the present utility model, but various modifications and variations can be made to the present utility model by those skilled in the art. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present utility model should be included in the protection scope of the present utility model.

Claims (10)

1. A box nipple, comprising:

an internally threaded joint (2);

an external threaded joint (1) which is in threaded connection with the internal threaded joint (2), wherein a threaded part (b) and a first stress relief part (a) arranged on one side of the threaded part (b) are arranged between the external threaded joint (1) and the internal threaded joint (2) along the axial direction of the sleeve threaded joint;

be equipped with first external screw thread (11) and second external screw thread (12) on external screw thread joint (1), be equipped with first internal screw thread (21) and second internal screw thread (22) on internal screw thread joint (2), second external screw thread (12) with second internal screw thread (22) screw thread cooperation forms screw thread portion (b), first external screw thread (11) with have first stress relief portion (a) between first internal screw thread (21), first stress relief portion (a) are including setting up first recess (3) of the top of first internal screw thread (21).

2. A box nipple according to claim 1, characterized in that, in the axial direction of the box nipple, from the outside to the inside, the first stress relief portion (a) and the threaded portion (b) are provided in sequence, the first internal thread (21) comprises a plurality of first protrusions arranged at intervals, each of the first protrusions having the first groove (3) open up on the crest.

3. A box nipple according to claim 2, characterized in that the line of generatrices of the first grooves (3) has an angle α1 with the axis of the first internal thread (21), said angle α1 being in the range 3 ° to 6 °.

4. A box nipple according to claim 2, characterized in that the height dimension of the plurality of first grooves (3) gradually decreases from the outside to the inside, the maximum height H2 of the plurality of first grooves (3) having the following relationship with the profile height H1 of the first internal thread (21): H2/H1 is more than or equal to 0.5 and less than or equal to 0.9.

5. A box thread joint according to any one of claims 1 to 4, characterized in that the box thread joint further comprises a second stress relief portion (c) provided between the pin thread joint (1) and the box thread joint (2), the first stress relief portion (a), the thread portion (b) and the second stress relief portion (c) being provided in this order from the outside to the inside in the axial direction of the box thread joint.

6. A box nipple according to claim 5, characterized in that the pin nipple (1) is further provided with a third external thread (13), the box nipple (2) is further provided with a third internal thread (23), and the second stress relief portion (c) comprises a second groove (4) provided at the crest of the third internal thread (23).

7. A box nipple according to claim 6, characterized in that the third internal thread (23) comprises a plurality of second protrusions arranged at intervals, each of the tips of the second protrusions being provided with the second grooves (4), the connecting generatrix of the plurality of second grooves (4) having an angle α2 with the axis of the third internal thread (23), the angle α2 being in the range of 1 ° to 3 °.

8. A box nipple according to claim 6, characterized in that the height dimension of the plurality of second grooves (4) increases gradually from the outside to the inside, the maximum height H3 of the plurality of second grooves (4) having the following relationship with the profile height H4 of the third internal thread (23): H3/H4 is more than or equal to 0.2 and less than or equal to 0.4.

9. A box nipple according to claim 6, characterized in that the second groove (4) is triangular or trapezoidal.

10. A box thread joint according to any one of claims 1 to 4, characterized in that the first groove (3) is triangular or trapezoidal.