WO2020183860A1 - ねじ継手 - Google Patents
ねじ継手 Download PDFInfo
- Publication number
- WO2020183860A1 WO2020183860A1 PCT/JP2019/050408 JP2019050408W WO2020183860A1 WO 2020183860 A1 WO2020183860 A1 WO 2020183860A1 JP 2019050408 W JP2019050408 W JP 2019050408W WO 2020183860 A1 WO2020183860 A1 WO 2020183860A1
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- screw
- degrees
- seal
- taper
- less
- Prior art date
Links
- 238000003780 insertion Methods 0.000 claims abstract description 34
- 230000037431 insertion Effects 0.000 claims abstract description 34
- 230000002093 peripheral effect Effects 0.000 claims description 17
- 230000008878 coupling Effects 0.000 claims description 5
- 238000010168 coupling process Methods 0.000 claims description 5
- 238000005859 coupling reaction Methods 0.000 claims description 5
- 239000002184 metal Substances 0.000 claims description 5
- 238000007789 sealing Methods 0.000 abstract description 9
- 230000006835 compression Effects 0.000 abstract description 6
- 238000007906 compression Methods 0.000 abstract description 6
- 229910000831 Steel Inorganic materials 0.000 description 7
- 239000010959 steel Substances 0.000 description 7
- 238000012360 testing method Methods 0.000 description 7
- 206010010904 Convulsion Diseases 0.000 description 6
- 238000004519 manufacturing process Methods 0.000 description 5
- 238000013461 design Methods 0.000 description 4
- 239000003921 oil Substances 0.000 description 4
- 239000003129 oil well Substances 0.000 description 4
- 238000012545 processing Methods 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 2
- 238000011161 development Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 238000002474 experimental method Methods 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000001154 acute effect Effects 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 238000009412 basement excavation Methods 0.000 description 1
- 238000005452 bending Methods 0.000 description 1
- 238000007796 conventional method Methods 0.000 description 1
- 239000010779 crude oil Substances 0.000 description 1
- 238000005553 drilling Methods 0.000 description 1
- 230000008030 elimination Effects 0.000 description 1
- 238000003379 elimination reaction Methods 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000002343 natural gas well Substances 0.000 description 1
- 239000003208 petroleum Substances 0.000 description 1
- 239000002436 steel type Substances 0.000 description 1
Images
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
-
- 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
-
- 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
-
- 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
- F16L15/04—Screw-threaded joints; Forms of screw-threads for such joints with additional sealings
-
- 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
- F16L15/06—Screw-threaded joints; Forms of screw-threads for such joints characterised by the shape of the screw-thread
Definitions
- the present invention relates to threaded joints, and more specifically, oil well pipes including tubing and casings generally used for exploration and production of oil wells and gas wells, that is, OCTG (oil country tubular goods), riser pipes, line pipes and the like.
- the present invention relates to a threaded joint having excellent compression resistance and sealing property, which is suitable for use in connecting steel pipes.
- Threaded joints are widely used to connect steel pipes used in oil production equipment such as oil country tubular goods.
- API American Petroleum Institute
- the above premium joint usually has a taper screw, a seal portion (metal touch seal portion), and a torque shoulder portion at the pipe end portions of the pipes connected to each other.
- These are the elements that make up each of a pin, which is a male-shaped portion provided in one tube, and a box, which is a female-shaped portion provided in the other tube and screwed or fitted to the male-shaped portion.
- These elements are designed so that male and female elements of the same name face each other when tightening a joint (meaning a threaded joint, the same applies hereinafter).
- the seal portion secures the seal property by metal contact between the box and the pin in the region of the seal portion.
- the pin seal portion provided on the pin usually has a convex pipe shaft cross-sectional shape
- the box seal portion provided on the box has a tapered pipe shaft cross-sectional shape.
- the torque shoulder portion is a shoulder surface that acts as a stopper during tightening of the joint.
- Patent Document 1 describes an example of the prior art of the tube axial interference taper screw.
- the subject of the invention described in Patent Document 1 is that, in consideration of the processing tolerance in actual production, contact is always made at the time of screw connection on both the load surface and the insertion surface regardless of the processing result within the tolerance. To make it happen.
- the invention described in Patent Document 1 defines the relationship between the load surface flank angle, the insertion surface flank angle, the gap generated on the screw top surface and the screw bottom surface, and the pipe axial clearance assumed from the machining tolerance. The equation is presented, and it is explained that by following this equation, contact can always occur at the time of screw connection on both the load surface and the insertion surface.
- Patent Document 1 prevents contact on the screw top surface and the screw bottom surface when the taper screw is tightened, and always guarantees contact on both the load surface and the insertion surface. is there.
- the amount of tightening required to realize contact is not taken into consideration, and the position in the pipe axial direction at the time of completion of tightening is greatly affected by the degree of dimensional variation during processing. Since the stop position in the pipe axial direction when tightening the screw has a great influence on the contact state of the seal portion, if the contact state is too small due to the dimensional variation of the taper screw, the sealing property becomes insufficient, and conversely, the contact is excessive. If it becomes a state, there is a concern that seizure may occur.
- an object of the present invention is to provide a threaded joint having excellent compressibility and sealing properties.
- the present inventors diligently studied to solve the above problems and obtained the following findings.
- the dimensional variation causes insufficient sealing property and seizure because the dimensional variation has a great influence on the contact state of the seal portion (hereinafter, also referred to as the seal interference amount). Therefore, it is important to design the taper screw and the seal portion that can suppress the influence of the dimensional variation on the amount of seal interference.
- a tapered screw composed of substantially trapezoidal threads by increasing the difference between the width of the thread top and the width of the thread bottom, the gap in the pipe axis direction changes with respect to the amount of rotation when the taper screw is tightened. The amount can be increased.
- the gist of the present invention completed based on the above findings is as follows.
- the male threaded portion comes into contact with the female threaded portion on both the insertion surface and the load surface with a gap left between the female threaded portion on both the screw top surface and the thread bottom surface due to the threaded coupling of the tapered screw.
- the outer peripheral surface of the nose portion has a pin seal portion having a convex tube shaft cross-sectional shape.
- the inner peripheral surface of the seal hole has a box seal portion having a tapered tube shaft cross-sectional shape in which a seal portion is formed by metal contact with the pin seal portion in the radial direction of the pipe by the screw connection.
- the flank angle of the insertion surface of the taper screw is 30 degrees or more and 50 degrees or less, and the load surface flank angle of the taper screw is -10 degrees or more and less than 0 degrees.
- the screw taper which is the amount of change in diameter per unit length in the pipe axis direction in the taper screw, is 1/10 or more and 1/4 or less.
- the seal taper angle of the box seal portion is 3 degrees or more and 10 degrees or less. Threaded joint.
- the shape, angle, and dimensions of the tapered screw and the seal portion specified in the present application mean the state before tightening the tapered screw (that is, the state in which no load is applied).
- the threaded joint 1 is a premium joint that connects an oil well pipe by a pin 2 and a box 3.
- the threaded joint 1 may be of an integral type in which steel pipes are directly connected to each other by a pin 2 and a box 3 as shown in FIG. 1, or steel pipes having pins 2 as shown in FIG. 2 are connected to each other. It may be a coupling type connected via a coupling having a box 3. Note that FIGS. 1 and 2 show only a cross section on one side of the tube axis X.
- the threaded joint 1 may be applied to a connection of a steel pipe other than an oil well pipe.
- the pin 2 is formed at the end of the pipe and has a male screw portion 4a of the taper screw 4 and an outer peripheral surface 5 of the nose portion located on the pipe end side of the male screw portion 4a.
- the box 3 has a female threaded portion 4b of the tapered screw 4 and an inner peripheral surface 6 of the seal hole facing the outer peripheral surface 5 of the nose portion.
- the male screw portion 4a is loaded with the insertion surface 9 in a state where a gap is left between the female screw portion 4b on both the screw top surface 7 and the screw bottom surface 8 due to the screw connection of the taper screw 4. It is configured to come into contact with the female threaded portion 4b on both sides of the surface 10. That is, the tapered screw 4 leaves a gap between the screw top surface 7 of the male screw portion 4a and the screw bottom surface 8'of the female screw portion 4b due to the screw connection, and the screw bottom surface 8 of the male screw portion 4a and the screw of the female screw portion 4b.
- the insertion surface 9 of the male threaded portion 4a and the insertion surface 9'of the female threaded portion 4b come into contact with each other, and the load surface 10 of the male threaded portion 4a and the female threaded portion 4b It is configured so that the load surface 10'is in contact with each other.
- the above-mentioned “gap” means a gap sufficient to cause tightening on both the insertion surface 9, 9'and the load surface 10, 10'when the tightening of the taper screw 4 is completed.
- the taper screw 4 achieves a strong connection by coming into contact with both the insertion surface 9, 9'and the load surface 10, 10'.
- the angle of a sharp angle formed by the insertion surface 9 as a straight line perpendicular to the tube axis X in the cross section including the tube axis X is defined as the insertion surface flank angle ⁇ , and the reference numerals of the insertion surface flank angle ⁇ are shown in FIG.
- the case where the insertion surface 9 is inclined toward the lateral side of the pipe axis X (hereinafter, also simply referred to as the radial outer side) toward the load surface 10 is positive.
- the angle of a sharp angle formed by the load surface 10 as a straight line perpendicular to the tube axis X in the pipe axis cross section is defined as the load surface flank angle ⁇ , and the sign of the load surface flank angle ⁇ is such that the load surface 10 is directed outward in the radial direction.
- the case of tilting toward the insertion surface 9 is positive (the sign of the load surface flank angle ⁇ shown in FIG. 3 is negative).
- the flank angle ⁇ of the insertion surface needs to be 30 degrees or more in order to secure the width difference between the thread top and the thread bottom.
- the flank angle ⁇ of the insertion surface is set to 30 degrees or more, the gap in the pipe axis direction (that is, the direction along the tube axis X) with respect to the amount of rotation when the taper screw 4 is tightened (that is, the insertion surfaces 9, 9'and The amount of change in the load surface (gap at the load surfaces 10 and 10') can be increased, and thus the influence of the dimensional variation (variation in the gap in the pipe axial direction) on the stop position in the pipe axial direction can be suppressed.
- the load surface flank angle ⁇ is preferably ⁇ 10 degrees or more and -3 degrees or less.
- the screw taper which is the amount of change in diameter per unit length in the pipe axis direction on the reference surface S that coincides with the screw bottom surface 8 of the male screw portion 4a, needs to be 1/10 or more.
- the taper screw 4 is tightened with a small amount of tightening, so that it is possible to suppress the influence on the pipe axial stop position at the time of completion of tightening due to dimensional variation.
- the screw taper must be 1/4 or less.
- the outer peripheral surface 5 of the nose portion has a pin seal portion 11a having a pipe shaft cross-sectional shape (that is, a shape in the pipe shaft cross section) that is curved in a convex shape.
- the cross-sectional shape of the pipe shaft of the pin seal portion 11a is not limited to the one that is curved in a convex shape, and may be a convex shape.
- the inner peripheral surface 6 of the seal hole forms a seal portion 11 that seals the fluid by metal contact with the pin seal portion 11a in the pipe radial direction (that is, the radial direction of the pipe axis X) by the screw connection of the taper screw 4.
- It has a box seal portion 11b having a tapered tube shaft cross-sectional shape. That is, the pin seal portion 11a and the box seal portion 11b form a seal portion 11 having a radial seal structure.
- the box seal portion 11b is a tapered surface having a truncated conical shape.
- the acute angle formed by the box seal portion 11b with a straight line parallel to the tube axis X in the cross section of the tube axis is defined as the seal taper angle ⁇ .
- the seal taper angle ⁇ needs to be 10 degrees or less in order to reduce the influence of the stop position in the pipe axial direction on the contact state (seal interference amount) of the seal portion 11 when the taper screw 4 is screwed.
- the seal taper angle ⁇ needs to be set to 3 degrees or more.
- seal taper angle ⁇ is less than 3 degrees, a large step is likely to be formed at the boundary between the seal portion and the screw portion, and in that case, it cannot be said that the design itself is established. This is because seizure easily occurs when the pin comes into contact with the stepped portion during screw connection.
- the screw height T is the distance between the intersection of the straight line perpendicular to the pipe axis X and the reference surface S in the cross section of the pipe shaft and the intersection of the straight line and the screw top surface 7.
- the screw height T is less than 0.04 inch, there is a concern that the contact surface cannot be sufficiently secured and the tapered screw 4 is excessively plastically deformed due to the axial force, and the function as a joint is lost.
- the screw height T exceeds 0.10 inch, there is a concern that the cross-sectional area of the dangerous cross section becomes small and the tensile strength of the joint cannot be sufficiently secured.
- the ratio T / W of the width W of the thread bottom portion and the screw height T in the male thread portion 4a is preferably 0.2 or more and 1.0 or less.
- the width W of the thread bottom includes a straight line including the intersection of a straight line including the load surface 10 and a straight line including the reference surface S in the pipe axis cross section and perpendicular to the pipe axis X, and the insertion surface 9. It is the distance from the straight line including the intersection of the including straight line and the straight line including the reference plane S and perpendicular to the tube axis X. If the T / W is less than 0.2, there is a concern that a sufficient contact surface cannot be secured. If the T / W exceeds 1.0, there is a concern that the cross-sectional area of the dangerous cross section cannot be sufficiently secured.
- the screw joint 1 has an insertion surface flank angle ⁇ of 30 degrees or more and 50 degrees or less, a load surface flank angle ⁇ of -10 degrees or more and less than 0 degrees, and a screw taper of 1/10 or more 1 Excellent compression resistance and sealing property can be exhibited by satisfying the condition that the seal taper angle ⁇ is 3 degrees or more and 10 degrees or less.
- the width W of the thread bottom of the male thread can be calculated from the insertion surface flank angle ⁇ and the load surface flank angle ⁇ , and the ratio T / W of the thread bottom width W and the thread height T is 0.38 to 0. It became .47.
- the joint efficiency was designed to be 75% at all levels, and in the airtightness test, a load of 75% was applied to both tension and compression for 95% VME.
- the influence of the dimensional variation on the seal interference amount could be suppressed to a level where there was no problem, and the test result was passed.
- seizure or leakage occurs in a comparative example that does not satisfy the above conditions (particularly, the insertion surface flank angle is 30 degrees or more, the screw taper is 1/10 or more, and the seal taper angle is 10 degrees or less).
- the test result was unsuccessful.
- seizure occurs during the tightening tightening test under the condition that the stop position in the pipe axis direction is large and the seal interference amount is excessive, and conversely, the stop position in the pipe axis direction is large and minus and the seal interference amount is too small. Under these conditions, a leak occurred during the airtightness test.
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- 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)
- Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
- Earth Drilling (AREA)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2020518819A JPWO2020183860A1 (ja) | 2019-03-14 | 2019-12-23 | ねじ継手 |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
JP2019-047480 | 2019-03-14 | ||
JP2019047480 | 2019-03-14 |
Publications (1)
Publication Number | Publication Date |
---|---|
WO2020183860A1 true WO2020183860A1 (ja) | 2020-09-17 |
Family
ID=72427242
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
PCT/JP2019/050408 WO2020183860A1 (ja) | 2019-03-14 | 2019-12-23 | ねじ継手 |
Country Status (4)
Country | Link |
---|---|
JP (1) | JPWO2020183860A1 (es) |
CN (2) | CN111692439A (es) |
AR (1) | AR118313A1 (es) |
WO (1) | WO2020183860A1 (es) |
Families Citing this family (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020183860A1 (ja) * | 2019-03-14 | 2020-09-17 | Jfeスチール株式会社 | ねじ継手 |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09119564A (ja) * | 1994-11-22 | 1997-05-06 | Sumitomo Metal Ind Ltd | 油井管用ねじ継手 |
JP2008516155A (ja) * | 2004-08-27 | 2008-05-15 | 住友金属工業株式会社 | 鋼管用ねじ継手 |
WO2018052140A1 (ja) * | 2016-09-16 | 2018-03-22 | 新日鐵住金株式会社 | ねじ継手 |
Family Cites Families (1)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
WO2020183860A1 (ja) * | 2019-03-14 | 2020-09-17 | Jfeスチール株式会社 | ねじ継手 |
-
2019
- 2019-12-23 WO PCT/JP2019/050408 patent/WO2020183860A1/ja active Application Filing
- 2019-12-23 JP JP2020518819A patent/JPWO2020183860A1/ja active Pending
-
2020
- 2020-03-09 CN CN202010157302.5A patent/CN111692439A/zh active Pending
- 2020-03-09 CN CN202020281700.3U patent/CN212377489U/zh not_active Expired - Fee Related
- 2020-03-11 AR ARP200100663A patent/AR118313A1/es unknown
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
JPH09119564A (ja) * | 1994-11-22 | 1997-05-06 | Sumitomo Metal Ind Ltd | 油井管用ねじ継手 |
JP2008516155A (ja) * | 2004-08-27 | 2008-05-15 | 住友金属工業株式会社 | 鋼管用ねじ継手 |
WO2018052140A1 (ja) * | 2016-09-16 | 2018-03-22 | 新日鐵住金株式会社 | ねじ継手 |
Also Published As
Publication number | Publication date |
---|---|
JPWO2020183860A1 (ja) | 2021-03-18 |
CN111692439A (zh) | 2020-09-22 |
AR118313A1 (es) | 2021-09-29 |
CN212377489U (zh) | 2021-01-19 |
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