CN210888837U - Oil casing threaded joint - Google Patents

Abstract

The utility model provides an oil casing threaded joint, which comprises a male end and a female end, wherein the male end and the female end are connected through threads; the male end comprises an outer nose end, the outer nose end is arranged at the end part of the male end, the female end comprises an inner nose end, and the inner nose end is arranged at the inner side of the female end; wherein, outer nose and outer nose cooperation form joint nose structure, and joint nose structure includes notch portion to improve the sealed contact pressure distribution of joint nose structure. The technical scheme of the utility model the problem that the screwed joint strength among the prior art is low, anti compound load ability is poor, sealing stability is poor has been solved effectively.

Description

Oil casing threaded joint

Technical Field

The utility model relates to a piecing devices technical field particularly, relates to an oil casing screwed joint.

Background

With the continuous development of exploration drilling technology, deep wells, ultra-deep wells and high-temperature and high-pressure wells are more and more, which requires that oil casing threaded joints have good structural integrity and sealing integrity, and more importantly, the robustness of sealing performance, namely, the excellent sealing robustness can be maintained under various complex and severe working conditions such as stretching, compression, internal pressure, external pressure, bending and the like and accidental external factors; meanwhile, the oil and gas field is generally in a severe natural environment, which requires that the oil casing threaded joint has good downhole operation performance and is convenient for downhole operation; meanwhile, the sealing surface can avoid accidental external force damage as much as possible in the processes of transporting, assembling and disassembling the threaded joint protective sleeve.

The standard API threaded oil casing has the problems of low connection strength of a threaded joint, poor composite load resistance, no air tightness and the like due to the design defects of the standard API threaded oil casing, cannot be qualified in harsh well conditions, and is mainly used for well conditions with low working condition requirements such as shallow wells, low-pressure wells and the like.

Chinese patent CN203925329 discloses an airtight oil casing joint, the technical thread of the patent is a trapezoidal structure, the tooth top and the tooth bottom are parallel to a thread bus, the end of an external thread joint is designed with a first positioning shoulder and a first sealing surface, an internal thread joint is designed with a second positioning shoulder and a second sealing surface which are corresponding, the first sealing surface and the second sealing surface are conical surfaces with an inclination angle of β, wherein tan β is 0.1-1.8, the more traditional structure has better processing and detection performance and excellent sealing performance, but the sealing structure is easy to be accidentally damaged during transportation or other operations, and the sealing structure is close to the positioning shoulder, the sealing performance is seriously affected by the stress state of the positioning shoulder, the stability of the sealing performance is not high, and meanwhile, in order to achieve 100% compression performance, the oil casing joint usually needs to adopt a pipe end necking process, and the production and processing cost is high.

Chinese patent CN2575286 discloses a utility model patent named "oil, sleeve pipe screwed joint", this patent technology screw thread is the partial trapezium structure of modified, and seal structure has adopted the outer seal face to be the cylinder, and the inner seal face is the structure of sphere, and this seal structure can remain stable sealing performance under oil jacket pipe stress state, but production and processing and detection difficulty, the easy unexpected damage of seal structure moreover.

Chinese patent CN202946041 discloses a practical novel technology named as "airtight zigzag threaded joint structure for oil well pipes", which adopts a zigzag tooth-shaped structure, where the tooth tops and the tooth bottoms of the parallel thread buses have high thread connection strength, and the influence of external load on sealing performance is reduced, and a sealing structure and a positioning shoulder form a wedge-shaped structure to maintain sealing stability, and the included angles between the inner and outer sealing surfaces and the vertical line are β 1 and β 2, respectively, β 1 is β 2-75-105 °, and the threaded joint has good connection strength and sealing performance, but the sealing structure is easily damaged accidentally during transportation or other operations, and the sealing structure is close to the positioning shoulder, and the sealing performance is seriously affected by the stress state of the positioning shoulder, and the sealing performance is not high in stability, and meanwhile, in order to achieve 100% compression performance, the threaded joint for oil well pipes often needs to adopt a pipe end necking process, and has high production and processing costs.

SUMMERY OF THE UTILITY MODEL

A primary object of the present invention is to provide a nipple for oil casing to solve the problems of low connection strength, poor anti-composite load capacity, and poor sealing stability of nipples in the prior art.

In order to achieve the purpose, the utility model provides an oil casing threaded joint, which comprises a male end and a female end, wherein the male end and the female end are connected through threads; the male end comprises an outer nose end, the outer nose end is arranged at the end part of the male end, the female end comprises an inner nose end, and the inner nose end is arranged at the inner side of the female end; wherein, outer nose and outer nose cooperation form joint nose structure, and joint nose structure includes notch portion to improve the sealed contact pressure distribution of joint nose structure.

Further, the joint nose structure further includes a sealing portion and a shoulder portion, the notch portion being disposed between the sealing portion and the shoulder portion.

Further, the outer nose end includes: the nose shoulder is arranged at the end part of the outer nose; the outer conical surface is connected with the nose end shoulder and is positioned on the outer surface of the outer nose end; the outer sealing conical surface is connected with the outer conical surface, and the outer sealing conical surface and the outer conical surface are arranged at an angle; the outer cylindrical surface is connected with the outer sealing conical surface and is positioned on one side far away from the outer conical surface; the nose shoulder and the outer conical surface form a negative angle structure, and the included angle between the outer conical surface and the axis of the outer nose is larger than the included angle between the outer sealing conical surface and the axis of the outer nose.

Further, the inner nose end includes: the positioning shoulder is matched with the nose shoulder; the inner cylindrical surface is arranged opposite to the outer conical surface; the inner sealing conical surface corresponds to the outer sealing conical surface; wherein, the outer conical surface and the inner cylindrical surface are matched to form a notch hole part.

Furthermore, an outer sealing cambered surface is arranged between the outer sealing conical surface and the outer cylindrical surface, and the outer sealing cambered surface and the outer sealing conical surface form an outer sealing structure; an inner sealing cambered surface is arranged on one side, away from the inner cylindrical surface, of the inner sealing conical surface, a transition cambered surface is arranged between the inner cylindrical surface and the inner sealing conical surface, and the inner sealing cambered surface, the inner sealing conical surface and the transition cambered surface form an inner sealing structure; the outer seal structure and the inner seal structure cooperate to form a seal.

Further, interior nose still includes the storage face, stores the face and is connected and be in the one side of keeping away from the interior sealed conical surface in the interior sealed cambered surface, stores face, interior sealed cambered surface and outer cylinder face cooperation back formation screw thread fat hold up tank.

Furthermore, the included angle between the outer sealing conical surface and the axis of the outer nose end is theta 1 which is more than or equal to 4 degrees and less than or equal to theta 1 which is more than or equal to 18 degrees; the included angle between the outer conical surface and the axis of the outer nose end is theta 2, and theta 2 is more than or equal to 5 degrees and less than or equal to 20 degrees; wherein θ 1 is less than θ 2.

Furthermore, the included angle between the shoulder at the nose end and the vertical plane of the axis of the pipe body is theta 3, theta 3 is more than or equal to 10 degrees and less than or equal to 20 degrees, the included angle between the internal thread sealing surface and the axis of the pipe body is theta 4, theta 4 is more than or equal to 4 degrees and less than or equal to 18 degrees, the included angle between the positioning shoulder and the axis of the pipe body is theta 5, and theta 5 is more than or equal to 10 degrees and less than or equal to 20 degrees.

Furthermore, the radius of the outer sealing cambered surface is R1, R1 is more than or equal to 15mm and less than or equal to 25mm, the radius of the inner sealing cambered surface is R4, R4 is more than or equal to 5mm and less than or equal to 10mm, the radius of the transition cambered surface is R5, and R5 is more than or equal to 5mm and less than or equal to 10 mm.

Furthermore, the nose length of the outer nose is L, and when the pipe body where the oil casing threaded joint is located is a casing pipe, L is more than or equal to 15mm and less than or equal to 20 mm; when the pipe body where the oil casing threaded joint is located is an oil pipe, L is more than or equal to 10mm and less than or equal to 15 mm.

Use the technical scheme of the utility model, the setting of notch portion can improve the sealed contact pressure distribution that connects the nose structure in the joint nose structure, and then improves screwed joint's joint strength, strengthens screwed joint's anti compound load ability, and the setting of notch portion can vacuole formation between screwed joint simultaneously, can make screwed joint have stronger gas tightness ability after cooperation sealing and circular bead portion, and then improves whole oil jacket pipe performance. The technical scheme of the utility model the problem that the screwed joint strength among the prior art is low, anti compound load ability is poor, sealing stability is poor has been solved effectively.

Drawings

The accompanying drawings, which form a part of the present application, are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the invention and not to limit the invention. In the drawings:

fig. 1 shows a schematic structural view of an embodiment of the invention after the male and female terminals are mated;

FIG. 2 shows an enlarged view of the structure of the joint nose at A in FIG. 1;

fig. 3 shows a schematic structural view of the male end of the present invention;

FIG. 4 shows an enlarged view of the outer nose at B in FIG. 3;

fig. 5 shows a schematic structural view of the female terminal of the present invention;

fig. 6 shows an enlarged view of the outer nose end at C in fig. 5.

Wherein the figures include the following reference numerals:

10. a male end; 11. an outer nose end; 111. a nose shoulder; 112. an outer conical surface; 113. an outer sealing conical surface; 114. an outer cylindrical surface; 12. a male end tube body; 20. a female end; 21. an inner nose end; 211. positioning the shoulder; 212. an inner cylindrical surface; 213. an inner sealing conical surface; 214. storing the noodles; 22. a female end pipe body; 30. a notch hole portion; 40. a sealing part; 50. a shoulder portion; 60. a thread grease storage tank.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail below with reference to the accompanying drawings in conjunction with embodiments.

It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the disclosure. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs.

Spatially relative terms, such as "above … …," "above … …," "above … …," "above," and the like, may be used herein for ease of description to describe one device or feature's spatial relationship to another device or feature as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if a device in the figures is turned over, devices described as "above" or "on" other devices or configurations would then be oriented "below" or "under" the other devices or configurations. Thus, the exemplary term "above … …" can include both an orientation of "above … …" and "below … …". The device may be otherwise variously oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.

Exemplary embodiments according to the present application will now be described in more detail with reference to the accompanying drawings. These exemplary embodiments may, however, be embodied in many different forms and should not be construed as limited to only the embodiments set forth herein. It is to be understood that these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the concept of the exemplary embodiments to those skilled in the art, in the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same devices are denoted by the same reference numerals, and thus the description thereof will be omitted.

As shown in fig. 1 to 6, the oil casing threaded joint according to the present embodiment includes a male end 10 and a female end 20, and the male end 10 and the female end 20 are connected by a thread. The male end 10 comprises an outer nose end 11, the outer nose end 11 being arranged at the end of the male end 10, the female end 20 comprising an inner nose end 21, the inner nose end 21 being arranged inside the female end 20. Wherein, outer nose end 11 and outer nose end 11 cooperate and form the joint nose end structure, and the joint nose end structure includes notch portion 30 to improve the sealed contact pressure distribution of joint nose end structure.

By using the technical scheme of the embodiment, the arrangement of the notch part 30 in the joint nose end structure can improve the sealing contact pressure distribution of the joint nose end structure, so that the connection strength of the threaded joint is improved, the composite load resistance of the threaded joint is enhanced, meanwhile, the arrangement of the notch part 30 can form a cavity between the threaded joint, and the threaded joint can have stronger gas sealing performance after being matched with the sealing part 40 and the shoulder part 50, so that the performance of the whole oil casing is improved. The technical scheme of this embodiment has solved the problem that the screwed joint strength among the prior art is low, anti compound load ability is poor, sealing stability is poor effectively.

It is noted that the male end 10 includes an outer nose 11 and a male end tube 12, and the female end 20 includes an inner nose 21 and a female end tube 22.

As shown in fig. 1 to 6, in the present embodiment, the joint nose structure further includes a sealing portion 40 and a shoulder portion 50, and the notch portion 30 is provided between the sealing portion 40 and the shoulder portion 50. The above structure can be better fitted to the notch portion 30 to ensure improved performance of the notch portion 30.

As shown in fig. 1 to 6, in the solution of the present embodiment, the external nose 11 includes a nose shoulder 111, an external tapered surface 112, an external sealing tapered surface 113 and an external cylindrical surface 114. A nose shoulder 111 is provided at the end of the outer nose 11. An outer tapered surface 112 connects with the nose shoulder 111 and is on the outer surface of the outer nose 11. The outer sealing conical surface 113 is connected with the outer conical surface 112, and the outer sealing conical surface 113 and the outer conical surface 112 are arranged at an angle. The outer cylindrical surface 114 is connected to the outer conical surface 113 and is located on a side away from the outer conical surface 112. The nose shoulder 111 and the outer conical surface 112 form a negative angle structure, and an included angle between the outer conical surface 112 and the axis of the outer nose 11 is larger than an included angle between the outer sealing conical surface 113 and the axis of the outer nose 11. Inner nose 21 includes a locating shoulder 211, an inner cylindrical surface 212, and an inner sealing cone 213. The locating shoulder 211 mates with the nose shoulder 111. The inner cylindrical surface 212 is disposed opposite the outer tapered surface 112. The inner sealing taper surface 213 corresponds to the outer sealing taper surface 113. Wherein the outer tapered surface 112 cooperates with the inner cylindrical surface 212 to form the slot portion 30. The above structure can form the sealing portion 40, the notch portion 30 and the shoulder portion 50 after the outer nose end 11 and the inner nose end 21 are engaged with each other, and the negative angle structure formed by the nose end shoulder 111 and the outer tapered surface 112 can improve the stability and the sealing performance of the threaded joint.

As shown in fig. 1 to 6, in the technical solution of the present embodiment, an outer sealing arc surface is disposed between the outer sealing conical surface 113 and the outer cylindrical surface 114, and the outer sealing arc surface and the outer sealing conical surface 113 form an outer sealing structure. An inner sealing arc surface is arranged on one side, away from the inner cylindrical surface 212, of the inner sealing conical surface 213, a transition arc surface is arranged between the inner cylindrical surface 212 and the inner sealing conical surface 213, and the inner sealing arc surface, the inner sealing conical surface 213 and the transition arc surface form an inner sealing structure. The outer seal structure and the inner seal structure cooperate to form a seal 40. In the structure, the outer sealing structure formed by the outer sealing cambered surface and the outer sealing conical surface 113 can gradually enhance the sealing property in the screwing process of the threaded joint, and finally the effect of complete sealing is achieved. The outer sealing curved surface and the outer sealing tapered surface 113 cooperate together to form an outer sealing structure having a high sealing contact pressure and a large sealing contact length. The inner sealing arc surface, the inner sealing conical surface 213 and the transition arc surface form an inner sealing structure, and also have a higher sealing contact pressure and a larger sealing contact length.

As shown in fig. 1 to 6, in the solution of this embodiment, the inner nose 21 further includes a storage surface 214, the storage surface 214 is connected to the inner sealing arc surface and is located at a side away from the inner sealing conical surface 213, and the storage surface 214, the inner sealing arc surface and the outer cylindrical surface 114 form the thread grease storage groove 60 after being matched. The arrangement of the thread grease storage groove 60 in the structure can store redundant thread grease at a thread part after the joint is screwed, and the influence of the pressure of the thread grease on the joint is reduced.

As shown in fig. 1 to 6, in the technical solution of the present embodiment, an included angle θ 1 between the outer sealing conical surface 113 and the axis of the outer nose end 11 is 4 ° to 18 °. The included angle between the outer conical surface 112 and the axial line of the outer nose end 11 is theta 2, and theta 2 is more than or equal to 5 degrees and less than or equal to 20 degrees. Wherein θ 1 is less than θ 2. The above structure can optimize the performance of the outer sealing tapered surface 113.

As shown in fig. 1 to 6, in the technical solution of the present embodiment, an included angle between the nose shoulder 111 and the vertical plane of the axis of the pipe body is θ 3 and 10 ° or more and 20 ° or less, an included angle between the internal thread sealing surface and the axis of the pipe body is θ 4 and 4 ° or more and 18 ° or less, and an included angle between the positioning shoulder 211 and the axis of the pipe body is θ 5 and 10 ° or more and θ 5 or less and 20 °. The structure can optimize the performance of the threaded joint and has better sealing effect.

As shown in fig. 1 to 6, in the technical solution of this embodiment, the radius of the outer sealing arc surface is R1, and R1 is greater than or equal to 15mm and less than or equal to 25mm, the radius of the inner sealing arc surface is R4, and R4 is greater than or equal to 5mm and less than or equal to 10mm, the radius of the transition arc surface is R5, and R5 is greater than or equal to 5mm and less than or equal to 10 mm. The structure can ensure the sealing strength and reduce the phenomenon of stress concentration.

As shown in fig. 1 to 6, in the technical solution of this embodiment, the nose length of the outer nose 11 is L, and when the pipe body where the oil casing threaded joint is located is a casing, L is greater than or equal to 15mm and less than or equal to 20 mm. When the pipe body where the oil casing threaded joint is located is an oil pipe, L is more than or equal to 10mm and less than or equal to 15 mm. Above-mentioned structure can make the body select for use the specification according to actual need to be suitable for the operation under the different work condition.

The specific embodiment is as follows:

1. the pipe body of the first embodiment of the design adopts a 139.7 × 12.7 mm-sized sleeve, the steel grade is 125V, the API standard is adopted to specify the outer diameter of a coupling, and the material performance meets the API standard requirements, the geometric parameters of the external thread joint are that the screw pitch P is 5 threads/inch, the tooth crest and the tooth bottom of the screw thread are parallel to a screw thread bus, the thread taper is 1:16, the sealing arc surface R1 is 20mm, theta 1 is 8 degrees, theta 2 is 12 degrees, the transition fillet R2 is 8mm, the transition fillet R3 is 0.6mm, theta 3 is 15 degrees, L is 15.5mm, the sealing arc surface R4 is 8mm, theta 4 is 8 degrees, R5 is 8mm, R6 is 0.5mm, theta 5 is 15 degrees, the connection strength of the sleeve thread joint reaches 4368kN, the compression strength reaches 4368kN, the air tightness reaches more than 137MPa, the external pressure resistance reaches more than 143MPa, the bending resistance reaches more than 30 MPa, and the sealing performance does not meet the requirements on the operation stability of the thread joint.

2. The pipe body of the second embodiment of the design adopts an oil pipe with 88.9 × 9.52.52 mm specification, the steel grade is P110, the API standard is adopted to specify the outer diameter of a coupling, and the material performance meets the API standard requirements, the geometric parameters of the external thread joint are that the screw pitch P is 7 threads/inch, the tooth crest and the tooth bottom of the screw thread are parallel to a thread generatrix, the thread taper is 1:16, R1 is 15mm, theta 1 is 5 degrees, theta 2 is 9 degrees, the transition fillet R2 is 6mm, the transition fillet R3 is 0.6mm, theta 3 is 15 degrees, L is 12.5mm, the sealing arc surface R4 is 6mm, theta 4 is 5 degrees, R5 is 6mm, R6 is 0.5mm, theta 5 is 15 degrees, the connection strength of the casing thread joint reaches 1800kN, the compression strength reaches 1800kN, the air tightness reaches 142MPa or more, the external pressure resistance reaches 145MPa, the buckling resistance reaches 145MPa or more, the bending resistance reaches 30 meters, and the sealing performance does not meet the requirements on the operation of the casing thread joint.

Compared with the prior art, the utility model discloses the technique has showing the progress, and the concrete presentation is in:

1. the optimized sealing surface structure and the optimized sealing surface position are adopted, so that the sealing integrity and the sealing robustness of the threaded joint are greatly improved, and meanwhile, the probability of accidental damage of the sealing surface structure in the processes of pipe transportation, thread protection sleeve assembly and disassembly and oil casing downhole operation is greatly reduced;

2. after the threaded connector is screwed up, 50 parts close to the shoulder part optimize a reasonable slotted hole structure, so that the distribution of sealing contact pressure of the sealing surface part is greatly optimized;

3. the shoulder part with a negative angle of 50 positions is adopted, so that the threaded joint has good compression resistance, torsion resistance and upper buckling positioning performance;

4. adopt the utility model discloses the oil casing screwed joint of technique is under the condition that need not throat or slight throat technology, and its comprehensive properties obtains greatly improving.

From the above description, it can be seen that the above-mentioned embodiments of the present invention achieve the following technical effects: use the technical scheme of the utility model, the setting of notch portion 30 can improve the sealed contact pressure distribution that connects the nose structure in the joint nose structure, and then improves screwed joint's joint strength, strengthens screwed joint's anti compound load ability, and the setting of notch portion 30 can vacuole formation between screwed joint simultaneously, can make screwed joint have stronger gas tightness ability after cooperation sealing 40 and circular bead portion 50, and then improves whole oil jacket pipe performance. The technical scheme of the utility model the problem that the screwed joint strength among the prior art is low, anti compound load ability is poor, sealing stability is poor has been solved effectively.

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 according to the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of stated features, steps, operations, devices, components, and/or combinations thereof, unless the context clearly indicates otherwise.

It should be noted that the terms "first," "second," and the like in the description and claims of this application and in the drawings described above are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the data so used is interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those illustrated or otherwise described herein. Furthermore, the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover a non-exclusive inclusion, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims (10)

1. A threaded joint for oil casings, comprising a male end (10) and a female end (20), the male end (10) and the female end (20) being connected by a thread;

the male end (10) comprises an outer nose end (11), the outer nose end (11) is arranged at the end of the male end (10), the female end (20) comprises an inner nose end (21), and the inner nose end (21) is arranged at the inner side of the female end (20);

wherein the outer nose end (11) and the outer nose end (11) cooperate to form a joint nose end structure comprising a notch portion (30) to improve a sealing contact pressure distribution of the joint nose end structure.

2. A threaded oil casing joint according to claim 1, characterized in that the joint nose structure further comprises a seal portion (40) and a shoulder portion (50), the notch portion (30) being provided between the seal portion (40) and the shoulder portion (50).

3. A threaded joint according to claim 2, characterized in that said external nose (11) comprises:

a nose shoulder (111), the nose shoulder (111) being disposed at an end of the outer nose (11);

an outer conical surface (112), said outer conical surface (112) being connected to said nose shoulder (111) and being located on the outer surface of said outer nose (11);

the outer sealing conical surface (113), the outer sealing conical surface (113) is connected with the outer conical surface (112), and the outer sealing conical surface (113) and the outer conical surface (112) are arranged at an angle;

an outer cylindrical surface (114), wherein the outer cylindrical surface (114) is connected with the outer sealing conical surface (113) and is positioned on one side far away from the outer conical surface (112);

the nose shoulder (111) and the outer conical surface (112) form a negative angle structure, and the included angle between the outer conical surface (112) and the axis of the outer nose end (11) is larger than the included angle between the outer sealing conical surface (113) and the axis of the outer nose end (11).

4. A threaded joint according to claim 3, characterized in that said inner nose (21) comprises:

a locating shoulder (211), said locating shoulder (211) fitting with said nose shoulder (111);

an inner cylindrical surface (212), the inner cylindrical surface (212) being disposed opposite the outer conical surface (112);

an inner sealing taper surface (213), the inner sealing taper surface (213) corresponding to the outer sealing taper surface (113);

wherein the outer tapered surface (112) cooperates with the inner cylindrical surface (212) to form the slot portion (30).

5. The oil casing threaded joint according to claim 4, characterized in that an outer sealing cambered surface is provided between the outer sealing conical surface (113) and the outer cylindrical surface (114), and the outer sealing cambered surface and the outer sealing conical surface (113) form an outer sealing structure;

an inner sealing arc surface is arranged on one side, away from the inner cylindrical surface (212), of the inner sealing conical surface (213), a transition arc surface is arranged between the inner cylindrical surface (212) and the inner sealing conical surface (213), and the inner sealing arc surface, the inner sealing conical surface (213) and the transition arc surface form an inner sealing structure;

the outer seal structure and the inner seal structure cooperate to form the seal (40).

6. A threaded oil casing joint according to claim 5, characterized in that the nose (21) further comprises a storage surface (214), the storage surface (214) being connected to the inner sealing cambered surface and being located on the side away from the inner sealing conical surface (213), the storage surface (214), inner sealing cambered surface and the outer cylindrical surface (114) cooperating to form a thread grease storage groove (60).

7. A threaded oil casing joint according to claim 3, characterized in that the angle θ 1 between the external sealing cone (113) and the axis of the external nose (11) is 4 ° ≦ θ 1 ≦ 18 °;

the included angle between the outer conical surface (112) and the axis of the outer nose end (11) is theta 2, and theta 2 is more than or equal to 5 degrees and less than or equal to 20 degrees;

wherein θ 1 is less than θ 2.

8. A threaded joint according to claim 4, wherein the angle θ 3 is between the nose shoulder (111) and the perpendicular to the axis of the tubular body at an angle of 10 ° to 20 °, the angle θ 4 is between the sealing surface of the female thread and the axis of the tubular body at an angle of 4 ° to 18 °, the angle θ 5 is between the positioning shoulder (211) and the axis of the tubular body at an angle of 10 °

≤θ5≤20°。

9. A threaded joint according to claim 5, characterized in that the radius of the external sealing arc is R1 and 15mm R1 and 25mm, the radius of the internal sealing arc is R4 and 5mm R4 and 10mm, the radius of the transition arc is R5 and 5mm R5 and 10 mm.

10. The oil casing threaded joint according to claim 1, wherein the nose length of the outer nose (11) is L, and when the pipe body where the oil casing threaded joint is located is a casing, L is greater than or equal to 15mm and less than or equal to 20 mm; when the pipe body where the oil casing threaded joint is located is an oil pipe, L is more than or equal to 10mm and less than or equal to 15 mm.

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