CA2706286C - A high-tightness threaded joint - Google Patents
A high-tightness threaded joint Download PDFInfo
- Publication number
- CA2706286C CA2706286C CA2706286A CA2706286A CA2706286C CA 2706286 C CA2706286 C CA 2706286C CA 2706286 A CA2706286 A CA 2706286A CA 2706286 A CA2706286 A CA 2706286A CA 2706286 C CA2706286 C CA 2706286C
- Authority
- CA
- Canada
- Prior art keywords
- thread
- internal
- external
- joint
- angle
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Fee Related
Links
- 238000007789 sealing Methods 0.000 claims abstract description 18
- 230000013011 mating Effects 0.000 abstract description 3
- 238000005299 abrasion Methods 0.000 abstract 1
- 230000006835 compression Effects 0.000 description 5
- 238000007906 compression Methods 0.000 description 5
- 238000000034 method Methods 0.000 description 3
- 238000005452 bending Methods 0.000 description 2
- 230000003993 interaction Effects 0.000 description 2
- 206010023230 Joint stiffness Diseases 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 230000000694 effects Effects 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16L—PIPES; JOINTS OR FITTINGS FOR PIPES; SUPPORTS FOR PIPES, CABLES OR PROTECTIVE TUBING; MEANS FOR THERMAL INSULATION IN GENERAL
- F16L15/00—Screw-threaded joints; Forms of screw-threads for such joints
- F16L15/001—Screw-threaded joints; Forms of screw-threads for such joints with conical threads
- F16L15/004—Screw-threaded joints; Forms of screw-threads for such joints with conical threads with axial sealings having at least one plastically deformable sealing surface
-
- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21B—EARTH OR ROCK DRILLING; OBTAINING OIL, GAS, WATER, SOLUBLE OR MELTABLE MATERIALS OR A SLURRY OF MINERALS FROM WELLS
- E21B17/00—Drilling rods or pipes; Flexible drill strings; Kellies; Drill collars; Sucker rods; Cables; Casings; Tubings
- E21B17/02—Couplings; joints
- E21B17/04—Couplings; joints between rod or the like and bit or between rod and rod or the like
- E21B17/042—Threaded
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Fluid Mechanics (AREA)
- Environmental & Geological Engineering (AREA)
- Physics & Mathematics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Earth Drilling (AREA)
- Mutual Connection Of Rods And Tubes (AREA)
Abstract
The invention relates to building oil and gas wells and can be used in casing strings and tubings. The inventive highly-tight screw joint comprises internal and external mating elements with conical surfaces.
The internal and external elements are provided with a thread. Said thread has supporting and embedded faces. A sealing unit is made in the form of a wedge on the side of a small diameter. The sealing unit is provided on the internal and external elements. The sealing unit consists of the parts of the internal and external elements. The internal and external elements of the sealing unit are formed by conical radial and conical stop faces. The conical radial face is made at an angle of 25°-35° to the normal to the thread axis.
The conical supporting surface is made at an angle of 10°-25° to the normal to thread axis. The design makes it possible to increase the reliability, the tightness and the strength of the joint, to ease the assembly and disassembly thereof, to improve the abrasion resistance of the joint and to extend the service life thereof.
The internal and external elements are provided with a thread. Said thread has supporting and embedded faces. A sealing unit is made in the form of a wedge on the side of a small diameter. The sealing unit is provided on the internal and external elements. The sealing unit consists of the parts of the internal and external elements. The internal and external elements of the sealing unit are formed by conical radial and conical stop faces. The conical radial face is made at an angle of 25°-35° to the normal to the thread axis.
The conical supporting surface is made at an angle of 10°-25° to the normal to thread axis. The design makes it possible to increase the reliability, the tightness and the strength of the joint, to ease the assembly and disassembly thereof, to improve the abrasion resistance of the joint and to extend the service life thereof.
Description
A High-Tightness Threaded Joint The invention pertains to the field of construction of building oil and gas wells and can be used for casings and tubing strings. A threaded joint for casings and tubing strings is high-tight and is designed for the use in wells characterized by high rate of shaft crookedness and/or severe operating conditions, such as high tension or compression loads, excessive internal and external pressures, and an environment with high concentrations of H2S and CO2.
Known is a technical solution protected by patent FR 1489013, priority 11.05.1965, describing a high-tightness threaded joint. In the known technical solution, the threaded joint has internal and external interfacing elements with tapered surfaces. The tapered surfaces of the elements have thread with a bearing face and inserted face. On the side of the smaller diameter of thread taper there is a sealing component made in the shape of a wedge and comprising parts of the internal element and external element.
However, a shortcoming of this threaded joint is that the sealing component is not sufficiently tight.
In addition, such design does not make it possible to achieve desired interference at low axial movements of the internal element, which lengthens the time between the first contact of sealing surfaces and achievement of the required interference. In addition, under severe operating conditions (high tension or compression loads, excessive internal and external pressures) there are flexural deformations that disrupt the contact of taper surfaces which results in unsealing of the threaded joint.
This technical solution is used as the closest analogue of the claimed technical solution.
In developing the invention, the objective was to design a high-tightness threaded joint that would make it possible to reassemble the threaded joint without damaging it, ensuring high tightness, improving behavior of the threaded joint in tension and bending, achieving guaranteed contact along the straight section of the thread bearing surface when screwing and unscrewing the joint, and increasing the resistance to compression loads.
The technical result being achieved is increased reliability and tightness of the joint, increased joint strength, simplified assembly-disassembly during operation, and increased wear resistance and life of the joint.
This technical result is achieved due to the fact that a high-tightness threaded joint has internal and external interfacing elements with tapered surfaces that have thread with bearing and inserted faces, and on the side of the smaller diameter of thread taper there is a sealing component made in the shape of a wedge and comprising parts of the internal and external elements. The sealing component internal and external parts are formed by a tapered radial surface and a tapered bearing surface, wherein the tapered =
Known is a technical solution protected by patent FR 1489013, priority 11.05.1965, describing a high-tightness threaded joint. In the known technical solution, the threaded joint has internal and external interfacing elements with tapered surfaces. The tapered surfaces of the elements have thread with a bearing face and inserted face. On the side of the smaller diameter of thread taper there is a sealing component made in the shape of a wedge and comprising parts of the internal element and external element.
However, a shortcoming of this threaded joint is that the sealing component is not sufficiently tight.
In addition, such design does not make it possible to achieve desired interference at low axial movements of the internal element, which lengthens the time between the first contact of sealing surfaces and achievement of the required interference. In addition, under severe operating conditions (high tension or compression loads, excessive internal and external pressures) there are flexural deformations that disrupt the contact of taper surfaces which results in unsealing of the threaded joint.
This technical solution is used as the closest analogue of the claimed technical solution.
In developing the invention, the objective was to design a high-tightness threaded joint that would make it possible to reassemble the threaded joint without damaging it, ensuring high tightness, improving behavior of the threaded joint in tension and bending, achieving guaranteed contact along the straight section of the thread bearing surface when screwing and unscrewing the joint, and increasing the resistance to compression loads.
The technical result being achieved is increased reliability and tightness of the joint, increased joint strength, simplified assembly-disassembly during operation, and increased wear resistance and life of the joint.
This technical result is achieved due to the fact that a high-tightness threaded joint has internal and external interfacing elements with tapered surfaces that have thread with bearing and inserted faces, and on the side of the smaller diameter of thread taper there is a sealing component made in the shape of a wedge and comprising parts of the internal and external elements. The sealing component internal and external parts are formed by a tapered radial surface and a tapered bearing surface, wherein the tapered =
2 radial surface is at a 250-350 angle to the normal to the thread axis, and the tapered bearing surface is at a 100-250 angle to the normal to the thread axis.
The table vividly demonstrates the effect of the angles on the threaded joint tightness, reliability and life. The table second column shows the pressure a pipe and joints must withstand while maintaining tightness. The third and fourth columns show stress readings taken when testing the joint; in the process, the joint itself had remained tight.
Average Contact Stresses Average Contact Stresses Hydrotesting Angle Combination in the Radial Seal After in the Radial Seal After Pressure, MPa Assembly, MPa Tension (0.801), MPa 250-100 793.7 690.2 300-150 64.5 1054.9 794.3 350-250 1158.5 865.1 These features are essential and interrelated, forming a stable set of essential features that is sufficient to achieve the stated technical result.
In the sealing component, the contact of the radial seal of the part of the internal element in the shape of a cone with the mating tapered surface of the part of an external element takes place with interference over a relatively small area. In this, high contact stresses occur which ensures high tightness.
The design makes it possible to reassemble the threaded joint without damaging the sealing surface, due to rapid achievement of the desired radial interference during the assembly process. In addition, such design of the sealing component makes it possible for the threaded joint to stay tight when exposed to substantial flexural loads. In this, the bearing surfaces protect the radial seal from excessive torque and compression.
To enhance the technical result, one can use a series of the following features.
In the high-tightness threaded joint, thread with a 1:16 taper is used.
The thread bearing face is at a 10-50 angle to the normal to the thread axis, and the inserted face is at a 70-250 angle. This angle of the thread bearing face ensures improved operation of the threaded joint in tension and bending, and the angle of the inserted face improves conditions for joint assembly when engaging the first several turns of the thread.
Along the bearing face straight section, the internal and external parts have different thread radii.
Such design makes it possible to improve threading the joint together, and increase its resistance to wear and compression loads.
Figure 1 shows a high-tightness threaded joint of casings with the internal and external elements.
The table vividly demonstrates the effect of the angles on the threaded joint tightness, reliability and life. The table second column shows the pressure a pipe and joints must withstand while maintaining tightness. The third and fourth columns show stress readings taken when testing the joint; in the process, the joint itself had remained tight.
Average Contact Stresses Average Contact Stresses Hydrotesting Angle Combination in the Radial Seal After in the Radial Seal After Pressure, MPa Assembly, MPa Tension (0.801), MPa 250-100 793.7 690.2 300-150 64.5 1054.9 794.3 350-250 1158.5 865.1 These features are essential and interrelated, forming a stable set of essential features that is sufficient to achieve the stated technical result.
In the sealing component, the contact of the radial seal of the part of the internal element in the shape of a cone with the mating tapered surface of the part of an external element takes place with interference over a relatively small area. In this, high contact stresses occur which ensures high tightness.
The design makes it possible to reassemble the threaded joint without damaging the sealing surface, due to rapid achievement of the desired radial interference during the assembly process. In addition, such design of the sealing component makes it possible for the threaded joint to stay tight when exposed to substantial flexural loads. In this, the bearing surfaces protect the radial seal from excessive torque and compression.
To enhance the technical result, one can use a series of the following features.
In the high-tightness threaded joint, thread with a 1:16 taper is used.
The thread bearing face is at a 10-50 angle to the normal to the thread axis, and the inserted face is at a 70-250 angle. This angle of the thread bearing face ensures improved operation of the threaded joint in tension and bending, and the angle of the inserted face improves conditions for joint assembly when engaging the first several turns of the thread.
Along the bearing face straight section, the internal and external parts have different thread radii.
Such design makes it possible to improve threading the joint together, and increase its resistance to wear and compression loads.
Figure 1 shows a high-tightness threaded joint of casings with the internal and external elements.
3 Figure 2 shows the thread profile of Section A in Fig. 1.
Figure 3 shows the sealing component corresponding to section E. in Fig. 1.
In the high-tightness threaded joint, thread (1) with a 1:16 taper is used.
The thread profile has a positive angle of 1 -5 along bearing face (2) and 70-250 along inserted face (3). The height of the thread profile of internal element (4) is lower than the height of the thread profile of external element (5). Sealing component (6) is on the side of the smaller diameter of thread taper, is made in the shape of a wedge and comprises parts of internal element (7) and external element (8). Parts of the internal and external elements are formed by tapered radial surfaces (9) and (10) and tapered bearing surfaces (11) and (12).
The radial seal is at a 250-350 angle to the normal to the thread axis, and the tapered seal is at a 100-250 angle to the normal to the thread axis.
The invention is explained using a specific example. It clearly demonstrates the possibility to achieve the above technical result. However, this is not the only possible example.
In the high-tightness threaded joint, thread with a 1:16 taper is used. The thread profile has a positive angle of 30 along the bearing face and 100 along the inserted face.
The height of the thread profile of the internal element is lower than the height of the thread profile of external element. The sealing component is on the side of the smaller diameter of thread taper, is made in the shape of a wedge and comprises parts of the internal element and the external element. Parts of the internal and external elements are formed by tapered radial and tapered bearing surfaces. The radial seal is at a 300 angle to the normal to the thread axis, and the tapered seal is at a 150 angle to the normal to the thread axis.
The high-tightness threaded joint works as follows.
When performing operations of screwing and unscrewing the threaded joint, the interaction of internal (4) and external (5) elements by means of thread (1) occurs first.
When screwing the joint, the surface of the external element is moving along the surface of the external element. Then, the tapered radial surface (7) and tapered bearing surface (8) of the internal element interact with the tapered radial surface (9) and tapered bearing surface (10) of the external element. Due to diametrical deformations of these surfaces, a "metal-to-metal" type sealing component is created.
When elements (4) and (5) move relative to each other, a forced contact of bearing surfaces (7) and (8) of the internal element and (9) and (10) of the external element occurs.
As a result, contact stresses develop on their surfaces. Magnitude of the stresses must be within the limits of elastic strains. All other conditions being equal, the level of contact stresses is determined by the size of contact areas of bearing surfaces (7), (8), (9) and (10).
The advantage of the claimed threaded joint compared to the known one is improved reliability of tightness, increased joint strength, facilitation of assembling-disassembling during operation, and increased wear resistance and life of the joint.
Figure 3 shows the sealing component corresponding to section E. in Fig. 1.
In the high-tightness threaded joint, thread (1) with a 1:16 taper is used.
The thread profile has a positive angle of 1 -5 along bearing face (2) and 70-250 along inserted face (3). The height of the thread profile of internal element (4) is lower than the height of the thread profile of external element (5). Sealing component (6) is on the side of the smaller diameter of thread taper, is made in the shape of a wedge and comprises parts of internal element (7) and external element (8). Parts of the internal and external elements are formed by tapered radial surfaces (9) and (10) and tapered bearing surfaces (11) and (12).
The radial seal is at a 250-350 angle to the normal to the thread axis, and the tapered seal is at a 100-250 angle to the normal to the thread axis.
The invention is explained using a specific example. It clearly demonstrates the possibility to achieve the above technical result. However, this is not the only possible example.
In the high-tightness threaded joint, thread with a 1:16 taper is used. The thread profile has a positive angle of 30 along the bearing face and 100 along the inserted face.
The height of the thread profile of the internal element is lower than the height of the thread profile of external element. The sealing component is on the side of the smaller diameter of thread taper, is made in the shape of a wedge and comprises parts of the internal element and the external element. Parts of the internal and external elements are formed by tapered radial and tapered bearing surfaces. The radial seal is at a 300 angle to the normal to the thread axis, and the tapered seal is at a 150 angle to the normal to the thread axis.
The high-tightness threaded joint works as follows.
When performing operations of screwing and unscrewing the threaded joint, the interaction of internal (4) and external (5) elements by means of thread (1) occurs first.
When screwing the joint, the surface of the external element is moving along the surface of the external element. Then, the tapered radial surface (7) and tapered bearing surface (8) of the internal element interact with the tapered radial surface (9) and tapered bearing surface (10) of the external element. Due to diametrical deformations of these surfaces, a "metal-to-metal" type sealing component is created.
When elements (4) and (5) move relative to each other, a forced contact of bearing surfaces (7) and (8) of the internal element and (9) and (10) of the external element occurs.
As a result, contact stresses develop on their surfaces. Magnitude of the stresses must be within the limits of elastic strains. All other conditions being equal, the level of contact stresses is determined by the size of contact areas of bearing surfaces (7), (8), (9) and (10).
The advantage of the claimed threaded joint compared to the known one is improved reliability of tightness, increased joint strength, facilitation of assembling-disassembling during operation, and increased wear resistance and life of the joint.
4 The invention is new and commercially practicable because, by using known processes used for making threaded pipe ends, it can be put into practice based on a new principle of interaction of mating surfaces that is different from the known designs.
Claims (4)
1. A high-tightness threaded joint that has an internal and external interfacing elements with tapered surfaces that have a thread with a bearing face and an inserted face, and a sealing component that is on a side of a smaller diameter of a thread taper, is made in the shape of a wedge and comprises parts of internal and external elements, distinct in that the internal and external parts of the sealing component are formed by tapered radial and tapered bearing surfaces, wherein the tapered radial surfaces are at a 25°-35° angle to the normal to a thread axis, and the tapered bearing surfaces are at a 10°-25°
angle to the normal to the thread axis.
angle to the normal to the thread axis.
2. A joint per claim 1, characterized in that thread with a 1:16 taper is used.
3. A joint per any one of claims 1, 2, characterized in that it uses thread with the bearing face at a 1°-5° angle to the normal to the thread axis and the inserted face at a 7°-25° angle.
4. A joint per claim 3, characterized in that the bearing face has a straight section, the internal and external parts having different thread radii along the straight section.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| RU2008102374 | 2008-01-25 | ||
| RU2008102374 | 2008-01-25 | ||
| PCT/RU2008/000237 WO2009093929A1 (en) | 2008-01-25 | 2008-04-18 | Highly-tight screw joint |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2706286A1 CA2706286A1 (en) | 2009-07-30 |
| CA2706286C true CA2706286C (en) | 2015-10-06 |
Family
ID=40901307
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA2706286A Expired - Fee Related CA2706286C (en) | 2008-01-25 | 2008-04-18 | A high-tightness threaded joint |
Country Status (4)
| Country | Link |
|---|---|
| CA (1) | CA2706286C (en) |
| DE (1) | DE112008003631T5 (en) |
| UA (1) | UA68624U (en) |
| WO (1) | WO2009093929A1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CA2721336A1 (en) * | 2008-04-30 | 2009-11-05 | Obshchestvo S Ogranichennoj Otvetstvennostyu "Tmk-Premium Servis" | Tight threaded joint for oil field pipes |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FR1489013A (en) | 1965-11-05 | 1967-07-21 | Vallourec | Assembly joint for metal pipes |
| IT1224745B (en) * | 1988-10-03 | 1990-10-18 | Dalmine Spa | METALLIC HERMETIC SEAL JOINT FOR PIPES |
| AR020495A1 (en) * | 1999-09-21 | 2002-05-15 | Siderca Sa Ind & Com | UNION THREADED HIGH RESISTANCE AND COMPRESSION UNION |
| RU2297512C2 (en) * | 2005-04-01 | 2007-04-20 | ОАО "Таганрогский металлургический завод" | Air-tight threaded oil-field pipe connection |
| RU66470U1 (en) * | 2005-09-08 | 2007-09-10 | Открытое акционерное общество "Северский трубный завод" | SEALED CONNECTION OF METAL PIPES WITH A DIAMETER 219-324 MM |
-
2008
- 2008-04-18 CA CA2706286A patent/CA2706286C/en not_active Expired - Fee Related
- 2008-04-18 WO PCT/RU2008/000237 patent/WO2009093929A1/en active Application Filing
- 2008-04-18 DE DE112008003631T patent/DE112008003631T5/en not_active Withdrawn
- 2008-04-18 UA UAU201005555U patent/UA68624U/en unknown
Also Published As
| Publication number | Publication date |
|---|---|
| DE112008003631T5 (en) | 2011-02-24 |
| WO2009093929A1 (en) | 2009-07-30 |
| CA2706286A1 (en) | 2009-07-30 |
| UA68624U (en) | 2012-04-10 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request |
Effective date: 20130418 |
|
| MKLA | Lapsed |
Effective date: 20220301 |
|
| MKLA | Lapsed |
Effective date: 20200831 |
|
| MKLA | Lapsed |
Effective date: 20200831 |