CN116927674A - Special threaded joint of high-air-tightness and anti-fatigue vibration oil pipe - Google Patents
Special threaded joint of high-air-tightness and anti-fatigue vibration oil pipe Download PDFInfo
- Publication number
- CN116927674A CN116927674A CN202210326547.5A CN202210326547A CN116927674A CN 116927674 A CN116927674 A CN 116927674A CN 202210326547 A CN202210326547 A CN 202210326547A CN 116927674 A CN116927674 A CN 116927674A
- Authority
- CN
- China
- Prior art keywords
- external thread
- internal thread
- thread
- sealing
- tooth
- 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.)
- Pending
Links
- 230000002929 anti-fatigue Effects 0.000 title description 5
- 238000007789 sealing Methods 0.000 claims abstract description 162
- 238000010168 coupling process Methods 0.000 claims abstract description 49
- 238000005859 coupling reaction Methods 0.000 claims abstract description 49
- 230000008878 coupling Effects 0.000 claims abstract description 47
- 230000007704 transition Effects 0.000 claims abstract description 24
- 239000002184 metal Substances 0.000 claims description 22
- 229910052751 metal Inorganic materials 0.000 claims description 22
- 230000009467 reduction Effects 0.000 claims description 9
- 238000003860 storage Methods 0.000 claims description 5
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims description 4
- 229910052802 copper Inorganic materials 0.000 claims description 4
- 239000010949 copper Substances 0.000 claims description 4
- 108700041286 delta Proteins 0.000 claims description 4
- 238000007747 plating Methods 0.000 claims description 4
- 210000003781 tooth socket Anatomy 0.000 claims description 3
- 238000005452 bending Methods 0.000 abstract description 18
- 239000002131 composite material Substances 0.000 abstract description 5
- 239000003208 petroleum Substances 0.000 abstract description 3
- 238000000034 method Methods 0.000 description 16
- 230000008569 process Effects 0.000 description 16
- 238000012360 testing method Methods 0.000 description 16
- 238000007906 compression Methods 0.000 description 13
- 230000006835 compression Effects 0.000 description 13
- 238000009661 fatigue test Methods 0.000 description 8
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 8
- 239000004519 grease Substances 0.000 description 6
- 238000012545 processing Methods 0.000 description 6
- 230000000694 effects Effects 0.000 description 5
- 239000007789 gas Substances 0.000 description 5
- 239000003345 natural gas Substances 0.000 description 4
- 230000007797 corrosion Effects 0.000 description 3
- 238000005260 corrosion Methods 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
- 238000011161 development Methods 0.000 description 3
- 238000010586 diagram Methods 0.000 description 3
- 238000004519 manufacturing process Methods 0.000 description 3
- 239000002343 natural gas well Substances 0.000 description 3
- 238000004458 analytical method Methods 0.000 description 2
- 239000011324 bead Substances 0.000 description 2
- 238000005516 engineering process Methods 0.000 description 2
- 229910000831 Steel Inorganic materials 0.000 description 1
- 102220498074 Transmembrane 4 L6 family member 20_N80Q_mutation Human genes 0.000 description 1
- 230000001133 acceleration Effects 0.000 description 1
- 230000006978 adaptation Effects 0.000 description 1
- 238000004026 adhesive bonding Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 230000000977 initiatory effect Effects 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 239000000463 material Substances 0.000 description 1
- 239000010959 steel Substances 0.000 description 1
- 238000006467 substitution reaction Methods 0.000 description 1
Classifications
-
- 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
-
- 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
- E21B17/08—Casing 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
- F16L15/001—Screw-threaded joints; Forms of screw-threads for such joints with conical threads
-
- 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
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Life Sciences & Earth Sciences (AREA)
- Geology (AREA)
- Mining & Mineral Resources (AREA)
- Physics & Mathematics (AREA)
- Environmental & Geological Engineering (AREA)
- Fluid Mechanics (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Non-Disconnectible Joints And Screw-Threaded Joints (AREA)
Abstract
The invention belongs to the technical field of petroleum exploitation pipes, and particularly relates to a special threaded joint of an oil pipe with high air tightness and fatigue vibration resistance, which comprises a coupling and a pipe body matched with the coupling, wherein the coupling is sequentially provided with an internal thread, an internal thread relief groove, an internal thread main sealing spherical surface, an internal thread sealing guide conical surface, an internal thread auxiliary sealing conical surface, a negative angle torque shoulder and a coupling middle hole along the axial direction, and the pipe body is sequentially provided with an external thread, an external thread transition surface, an external thread main sealing conical surface, an external thread sealing guide conical surface, an external thread auxiliary sealing conical surface, a pipe body torque-resisting end surface, a pipe end inner flat cylindrical surface and a pipe end inner flat conical surface along the axial direction. The sealing structure of the threaded joint adopts a double-stage bimetal interference sealing structure, and ensures the safety and reliability of the sealing performance of the threaded joint under the composite loads of stretching/compressing, bending, internal pressure/external pressure, impact, fatigue vibration and the like.
Description
Technical Field
The invention belongs to the technical field of petroleum exploitation pipes, and particularly relates to a special threaded joint of an oil pipe with high air tightness and fatigue vibration resistance.
Background
In recent years, along with the acceleration of natural gas production and consumption speed, the development force of unconventional natural gas such as shale gas is increased in China, and the conversion from conventional natural gas to unconventional natural gas is started to be realized. The unconventional natural gas well has high exploitation difficulty and complex process, and in the production process, the production yield and pressure of the gas well are changed, the size of the pipe column is inconsistent, the bending deformation of the oil pipe and the like can cause the vibration of the oil pipe column, the stress born by the pipe column is increased, and the stress concentration is aggravated, so that the fatigue damage of the oil pipe column is aggravated, and the oil pipe column falls into the well. Therefore, the combination property of the oil pipe threaded connection joint is required to be higher, and the oil pipe threaded connection joint is required to have excellent compression property, tensile strength, sealing property, bending property, sticking resistance, high temperature resistance, torque resistance, fatigue vibration resistance and the like.
Currently, the joint used for oil casings is usually an API threaded joint, which is a standard joint manufactured according to API (american petroleum institute) standards, and the thread shape is a round thread or buttress thread. The bearing surface angle and the guide surface angle of the round thread are both 30 degrees. The buttress thread bearing face angle is 3 degrees and the guide face angle is 10 degrees. The thread form has the advantages of mature technology, convenient processing and good interchangeability. The disadvantage is that under tensile load, a large radial component force is generated on the bearing surface, especially the circular thread is more serious, and the radial component force has adverse effect on the connection quality of the joint; in addition, the screw thread has the connecting function and the sealing function, but gaps exist between the engagement of the screw threads, so that the sealing performance is unreliable. It is due to the above drawbacks that API threaded joints are prone to failure.
Disclosure of Invention
Aiming at the problems, the invention aims to provide the special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance, which has excellent joint comprehensive performance, high compression resistance, high connection strength, high sealing, high bending resistance, high sticking buckle, high torque resistance, end surface corrosion resistance, fatigue vibration resistance, simple structure, easy processing, smooth screwing-on, accurate positioning and the like, and can solve the problems of reliability and sealing structural integrity of threaded connection required by unconventional natural gas well development.
The technical scheme of the invention is as follows: the utility model provides a high air tightness performance and anti fatigue vibration oil pipe special screwed joint, includes the coupling, with coupling matched with body, the coupling is equipped with internal thread, internal thread clearance groove, internal thread main seal sphere, internal thread seal guide cone, internal thread pair seal cone, negative angle moment of torsion circular bead, coupling mesopore in proper order along the axis direction, the body is equipped with external thread, external thread transitional surface, external thread main seal cone, external thread seal guide cone, external thread pair seal cone, body antitorque moment terminal surface, pipe end internal plane cylindrical surface and pipe end internal plane conical surface in proper order along the axis direction, coupling and body threaded connection back, internal thread main seal sphere and external thread main seal cone cooperation form main seal structure, internal thread seal guide cone and external thread seal guide cone cooperation form seal guide structure, internal thread pair seal cone and external thread pair seal cone cooperation form pair seal structure, anti moment of torsion circular bead and body antitorque moment terminal surface metal interference contact, internal thread tooth top and external thread tooth bottom metal contact, internal thread tooth bottom interference profile and external thread seal surface, external thread clearance groove thread guide surface and external thread seal groove thread bearing surface and external thread clearance groove metal contact.
The internal thread tooth type is a coupling buttress thread and comprises a tooth top, a tooth bottom, a guide surface, a bearing surface, an internal thread tooth height H, an internal thread tooth groove A1 and an internal thread tooth thickness A2, wherein the tooth top and the tooth bottom are parallel to the central axis of the coupling; the guide surfaces are double-angle combined guide surfaces, the angle gamma 1 of the first guide surface is 10 degrees to 13 degrees, the angle gamma 2 of the second guide surface is 30 degrees to 40 degrees, and the height H of the second guide surface is 1/3-1/2 of the tooth height H of the internal thread; the negative angle theta 1 of the internal thread bearing surface is 1-3 degrees; the range of the tooth height H of the internal thread is 1.0mm-1.2mm; the difference between the tooth space A1 of the internal thread and the tooth thickness A2 of the internal thread is 0.05mm-0.15mm.
The external thread tooth form is in a buttress shape and comprises a tooth top, a tooth bottom, a guide surface, a bearing surface, an external thread tooth height H1, an external thread tooth groove C2 and an external thread tooth thickness C1, wherein the tooth top and the tooth bottom are parallel to the central axis of the pipe body; the angle gamma 3 of the external thread guide surface is 10 degrees to 13 degrees; the negative angle theta 2 of the external thread bearing surface is 1-3 degrees; the tooth height H1 of the external thread is in the range of 0.9mm-1.1mm; the difference between the external thread tooth groove C2 and the external thread tooth thickness C1 is 0.05m-0.15mm.
The internal thread and the external thread are small taper conical threads, the taper is 1:18, 6 threads per inch are formed, phosphating or copper plating treatment is carried out on the surface of the internal thread, and the interference contact range of the top of the internal thread and the bottom metal of the external thread is 0.05mm-0.15mm.
The radius range of the main sealing sphere of the internal thread is 50mm-70mm, and the length range is 3.5mm-4mm; the angle range of the internal thread sealing guide conical surface is 2-4 degrees, and the length range is 3-4 mm; the angle range of the internal thread pair sealing conical surface is 14-17 degrees, and the length range is 2.7-3.2 mm; the angle range of the main sealing conical surface of the external thread is 9-12 degrees, and the length is 5.3-5.8mm; the angle range of the external thread sealing guide surface is 2-5 degrees, and the length is 2.5-3.5mm; the angle range of the external thread pair sealing conical surface is 11-14 degrees, and the length is 2.3-2.8 mm; after the internal thread is in threaded connection with the external thread, the main sealing spherical surface of the internal thread is in metal interference contact with the main sealing conical surface of the external thread, the interference length L1 is 2mm-4mm, and the interference delta 1 is 0.3mm-0.6mm; the internal thread pair sealing conical surface is in metal interference contact with the external thread pair sealing conical surface, the interference length L2 is in the range of 0mm-3mm, and the interference delta 2 is in the range of 0mm-0.6mm.
The anti-torque shoulder of the coupling and the anti-torque end face of the pipe body are both negative angles, the shoulder bearing angle phi 1 and the end face negative angle phi 2 are the same in degrees and are in the range of 13 degrees to 15 degrees, the anti-torque end face of the pipe body and the negative sealing conical surface of the external thread are in arc transition, the radius of the arc is 0.5mm to 1mm, and the main sealing conical surface of the external thread and the transitional surface of the external thread are in arc transition; the anti-torque shoulder of the coupling and the sealing conical surface of the internal thread pair are in arc transition, the radius of the arc is 0.5mm-1mm, and the main sealing spherical surface of the internal thread and the tool retracting groove of the internal thread are in arc transition.
The end part of the pipe body is subjected to diameter reduction treatment, the diameter reduction length is 10mm-15mm, the wall thickness is 0.5mm-0.7mm, the length of the inner flat cylindrical surface of the pipe end of the pipe body is 10mm-15mm, and the conical cone angle alpha of the inner flat conical surface of the pipe end is 5-10 degrees.
The invention has the technical effects that: 1. the coupling torque-resistant shoulder and the pipe body torque-resistant end face of the threaded joint are both negative angles, so that the accuracy of the make-up positioning is ensured, and meanwhile, the coupling torque-resistant shoulder and the pipe body torque-resistant end face are in metal interference contact with each other to have an auxiliary sealing effect; 2. the sealing structure of the threaded joint adopts a double-stage bimetal interference sealing structure, the main sealing spherical surface of the internal thread and the main sealing conical surface of the external thread are matched to form a main sealing structure, the auxiliary sealing conical surface of the internal thread and the auxiliary sealing conical surface of the external thread are matched to form an auxiliary sealing structure, the torque-resistant shoulder of the coupling is in metal interference contact with the torque-resistant end surface of the pipe body, the tooth tip of the internal thread is in metal interference contact with the tooth bottom of the external thread, and the sufficient sealing interference length and contact pressure can ensure the safety and reliability of the sealing performance of the threaded joint under the composite loads of stretching/compression, bending, internal pressure/external pressure, impact, fatigue vibration and the like; the main sealing structure is far away from the torque shoulder, the influence of the torque shoulder on the sealing is greatly reduced, the tensile and continuous compression resistance capacity is enhanced, and meanwhile, the influence of end face corrosion on the sealing can be reduced; the auxiliary sealing structure is close to the torque shoulder, so that stress concentration at the position of the shoulder can be greatly reduced, and an auxiliary sealing effect can be achieved; a sealing guide structure is arranged, and the main sealing structure is protected from being damaged when the main sealing structure is buckled; the position of the main sealing structure is close to the screw thread, so that the damage of the pipe body sealing structure in the detection, transportation, field operation and pipe column service process is avoided; 3. the thread tooth top and the tooth bottom of the threaded joint are parallel to the axis of the pipe body, and the automatic deviation adjusting function is realized when the threaded joint is fastened, so that the on-site fastening is easy; the internal thread and the external thread are small taper conical threads, so that the length of the complete thread can be increased compared with other large taper threads, and meanwhile, the bearing surfaces of the internal thread and the external thread are both in negative angles, so that the connection strength of the threads is greatly enhanced; 4. the internal thread tooth bottom and the external thread tooth top of the threaded joint are separated, so that the flow of redundant thread grease in the threads is facilitated, and the internal pressure of the thread grease in the screwing process is reduced; the internal thread adopts the adaptation of the combined guide surface and the external thread guide surface, which is beneficial to increasing the internal clearance of the thread and greatly improving the anti-galling performance, and has the characteristics of easy threading, convenient field operation and the like; 5. the tool retracting groove is arranged at the tail end of the coupling internal thread of the threaded joint, so that a multi-tooth tool processing technology is convenient to use, and the processing efficiency is improved; the transition surface of the internal thread tool retracting groove and the external thread forms an oil storage groove, and has the function of storing redundant thread grease; 6. according to the threaded joint, the pipe end is subjected to diameter reduction treatment, so that the thickness of the pipe end face is increased, the ovality of the pipe end is reduced, and the stretching resistance and the compression performance of the joint can be improved; 7. the sealing structure adopted by the threaded joint and the threaded structure are matched, so that the joint has good connection strength and sealing integrity when bearing composite loads such as stretching, compression, bending, internal pressure, external pressure, high temperature and the like, and can meet the severe requirements of unconventional gas wells such as high-temperature high-pressure deep gas wells and the like on the joint.
Further description will be made below with reference to the accompanying drawings.
Drawings
FIG. 1 is a schematic view of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the invention.
Fig. 2 is a schematic diagram of a coupling structure of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the invention.
Fig. 3 is a schematic diagram of a pipe body structure of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the invention.
Fig. 4 is an enlarged partial schematic view of a collar seal portion of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the present invention.
Fig. 5 is an enlarged schematic view of a part of a sealing portion of a body of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the present invention.
Fig. 6 is an enlarged schematic view of a seal fit of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the present invention.
Fig. 7 is a diagram showing the internal thread profile of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the present invention.
Fig. 8 is an external thread profile of a special threaded joint for an oil pipe with high air tightness and fatigue vibration resistance according to an embodiment of the present invention.
FIG. 9 is a stress chart of the seal and shoulder at each load point in the high temperature A series test of a special threaded joint for a high gas tightness and fatigue vibration resistant tubing in accordance with an embodiment of the present invention.
Fig. 10 is a graph showing the contact pressure and contact length test of the main seal of the special threaded joint of the oil pipe with high air tightness and fatigue vibration resistance at each load point in the high-temperature a series test according to the embodiment of the invention.
FIG. 11 is a graph showing the contact area test of the main seal of a special threaded joint for a high-gas-tightness and anti-fatigue vibration oil pipe at each load point in a high-temperature A series test according to an embodiment of the present invention.
FIG. 12 is a chart showing the test of the alternating strain loading history of a special threaded joint for a high-airtight and anti-fatigue vibration oil pipe in a resonance bending fatigue test according to an embodiment of the present invention.
Reference numerals: the pipe comprises A1-coupling, A2-pipe body, a 3-internal thread, a 4-internal thread relief groove, a 5-internal thread main sealing sphere, a 6-internal thread sealing guiding cone, a 7-internal thread auxiliary sealing cone, an 8-negative angle torque shoulder, a 9-coupling middle hole, a 10-external thread, a 11-external thread transition surface, a 12-external thread main sealing cone, a 13-external thread sealing guiding cone, a 14-external thread auxiliary sealing cone, a 15-pipe body torque-resisting end surface, a 16-pipe end inner flat cylindrical surface, a 17-pipe end inner flat conical surface, a 18-oil storage groove, an H-internal thread tooth height, an A1-internal thread tooth socket, an A2-internal thread tooth thickness, a gamma 1-first guiding surface angle, a gamma 2-second guiding surface angle, an H-second guiding surface height, a gamma 1-internal thread bearing surface negative angle, an H1-external thread tooth height, a C2-external thread tooth socket, a C1-external thread tooth thickness, a gamma 3-external thread guiding surface angle, a theta 2-external thread bearing surface negative angle, an L1-interference fit interference length, an L2-internal interference fit, an L-internal sealing cone angle, a delta sealing cone angle, a phi-clearance angle, a phi-delta sealing surface, a phi-2-clearance seal angle, a phi-delta sealing surface, and a phi-clearance angle, and a phi-delta sealing surface.
Detailed Description
Example 1
As shown in fig. 1-3, the special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance comprises a coupling 1 and a pipe body 2 matched with the coupling 1, wherein the coupling 1 is sequentially provided with an internal thread 3, an internal thread relief groove 4, an internal thread main sealing spherical surface 5, an internal thread sealing guiding conical surface 6, an internal thread auxiliary sealing conical surface 7, a negative angle torque shoulder 8 and a coupling middle hole 9 along the axial direction, the pipe body 2 is sequentially provided with an external thread 10, an external thread transition surface 11, an external thread main sealing conical surface 12, an external thread sealing guiding conical surface 13, an external thread auxiliary sealing conical surface 14, a pipe body anti-torque end face 15, a pipe end inner flat cylindrical surface 16 and a pipe end inner flat surface 17 along the axial direction, after the coupling 1 and the pipe body 2 are in threaded connection, the internal thread main sealing spherical surface 5 and the external thread main sealing conical surface 12 are matched to form a main sealing structure, the internal thread sealing guiding conical surface 6 and the external thread sealing guiding conical surface 13 are matched to form an auxiliary sealing structure, the internal thread auxiliary sealing conical surface 7 and the external thread auxiliary sealing conical surface 14 are matched to form an auxiliary sealing structure, the interference fit surface 8 is in contact with the pipe body anti-torque end face 10, the pipe end face 3 is separated from the external thread top face 10, and the pipe body anti-torque end face 10 is in contact with the external thread sealing conical surface 10, and the pipe end face 3 is in contact with the external thread end face 10, and the anti-torque end face is in contact with the external thread groove 3.
In the practical use process, the sealing structure of the threaded joint adopts a double-stage bimetal interference sealing structure, the main sealing spherical surface 5 of the internal thread and the main sealing conical surface 12 of the external thread are matched to form a main sealing structure, the auxiliary sealing conical surface 7 of the internal thread and the auxiliary sealing conical surface 14 of the external thread are matched to form an auxiliary sealing structure, the torque-resisting shoulder 8 of the coupling is in metal interference contact with the torque-resisting end surface 15 of the pipe body, the tooth crest of the internal thread 3 is in metal interference contact with the tooth bottom of the external thread 10, and the sufficient sealing interference length and the contact pressure can ensure the safety and reliability of the sealing performance of the threaded joint under the composite loads of stretching/compression, bending, internal pressure/external pressure, impact, fatigue vibration and the like; the main sealing structure is far away from the torque shoulder, so that the influence of the torque shoulder on sealing is greatly reduced, and the tensile and continuous compression resistance is enhanced; the auxiliary sealing structure is close to the negative-angle torque shoulder 8, so that the stress concentration at the position of the shoulder can be greatly reduced, and the auxiliary sealing effect can be realized; the internal thread sealing guide conical surface 6 and the external thread sealing guide conical surface 13 are matched to form a sealing guide structure, and the sealing guide structure is arranged to protect the main sealing structure from being damaged during screwing; the position of the main sealing structure is close to the screw thread, so that the damage of the pipe body sealing structure in the detection, transportation, field operation and pipe column service process is avoided.
Example 2
Preferably, in this embodiment, as shown in fig. 4, 6 and 7, the internal thread 3 is preferably a coupling buttress thread, including a tooth top, a tooth bottom, a guide surface, a bearing surface, an internal thread tooth height H, an internal thread tooth slot A1 and an internal thread tooth thickness A2, where the tooth top and the tooth bottom are parallel to the central axis of the coupling 1; the guide surfaces are double-angle combined guide surfaces, the angle gamma 1 of the first guide surface is 10 degrees to 13 degrees, the angle gamma 2 of the second guide surface is 30 degrees to 40 degrees, and the height H of the second guide surface is 1/3-1/2 of the tooth height H of the internal thread; the negative angle theta 1 of the internal thread bearing surface is 1-3 degrees; the range of the tooth height H of the internal thread is 1.0mm-1.2mm; the difference between the tooth space A1 of the internal thread and the tooth thickness A2 of the internal thread is 0.05mm-0.15mm.
In the actual use process, the internal thread 3 tooth form of the threaded joint is a coupling buttress thread, and the tooth top and the tooth bottom are parallel to the central axis of the coupling 1; the guide surface is a double-angle combined guide surface, the thread tooth top and the tooth bottom are parallel to the axis of the coupling 1, an automatic deviation adjusting function is realized when the coupling is buckled, the coupling is easy to buckle on site, the internal thread adopts the combined guide surface to be matched with the external thread guide surface, the internal clearance of the thread is increased, the anti-buckling performance is greatly improved, meanwhile, the coupling has the characteristics of easy buckling, convenient site operation and the like, and meanwhile, the internal thread bearing surface adopts a negative angle, and the connection strength of the thread is greatly enhanced.
Example 3
Preferably, in this embodiment, as shown in fig. 5, 6 and 8, the external thread 10 is preferably in a buttress shape, and includes a tooth top, a tooth bottom, a guiding surface, a bearing surface, an external thread tooth height H1, an external thread tooth slot C2 and an external thread tooth thickness C1, where the tooth top and the tooth bottom are parallel to the central axis of the pipe body 2; the angle gamma 3 of the external thread guide surface is 10 degrees to 13 degrees; the negative angle theta 2 of the external thread bearing surface is 1-3 degrees; the tooth height H1 of the external thread is in the range of 0.9mm-1.1mm; the difference between the external thread tooth groove C2 and the external thread tooth thickness C1 is 0.05m-0.15mm.
In the practical use process, the external thread 10 of the threaded joint is a buttress thread, the tooth top and the tooth bottom are parallel to the central axis of the pipe body 2, the tooth top and the tooth bottom of the thread are parallel to the axis of the pipe body, the automatic deviation adjusting function is realized during the screwing, the on-site screwing is easy, and meanwhile, the bearing surface of the external thread adopts a negative angle, so that the connection strength of the thread is greatly enhanced.
Example 4
Preferably, in this embodiment, on the basis of embodiment 1, 2 or 3, the female thread 3 and the male thread 10 are preferably small taper conical threads, the taper is 1:18, 6 teeth per inch, the surface of the female thread 3 is subjected to phosphating or copper plating, and the interference contact range of the tooth crest of the female thread 3 and the bottom metal of the male thread 10 is 0.05mm-0.15mm.
In the actual use process, the internal thread and the external thread are both small taper conical threads, compared with other large taper threads, the length of the complete thread can be increased, and meanwhile, the bearing surfaces of the internal thread and the external thread are both in negative angles, so that the connection strength of the threads is greatly enhanced; the surface of the internal thread 3 is subjected to phosphating or copper plating treatment, so that the anti-galling performance of the thread and the sealing surface can be improved. Before the thread connection, the internal thread and the external thread are coated with thread grease, so that the anti-thread gluing performance and the sealing performance of the thread surface can be further improved; after the threads are connected, the metal interference contact range of the tooth tops of the internal threads 3 and the tooth bottoms of the external threads 10 is 0.05mm-0.15mm, and the tooth bottoms of the internal threads 3 and the tooth tops of the external threads 10 are mutually separated, so that the flow of redundant thread grease in the threads is facilitated, and the internal pressure of the thread grease in the screwing process is reduced; the inner thread guide surface and the outer thread guide surface are mutually separated, and the inner thread tooth form the first sealing structure of the invention.
Example 5
Preferably, on the basis of embodiment 1, 2 or 4, in this embodiment, preferably, the radius range of the internal thread main sealing sphere 5 is 50mm-70mm, and the length range is 3.5mm-4mm; the angle range of the internal thread sealing guide conical surface 6 is 2-4 degrees, and the length range is 3-4 mm; the angle range of the internal thread pair sealing conical surface 7 is 14-17 degrees, and the length range is 2.7-3.2 mm; the angle range of the main sealing conical surface 12 of the external thread is 9-12 degrees, and the length is 5.3-5.8mm; the angle range of the external thread sealing guide surface 13 is 2 degrees to 5 degrees, and the length is 2.5 mm to 3.5mm; the angle range of the external thread pair sealing conical surface 14 is 11-14 degrees, and the length is 2.3-2.8 mm; after the internal thread 3 is in threaded connection with the external thread 10, the internal thread main sealing spherical surface 5 is in metal interference contact with the external thread main sealing conical surface 12, the interference length L1 is 2mm-4mm, and the interference delta 1 is 0.3mm-0.6mm; the internal thread pair sealing conical surface 7 is in metal interference contact with the external thread pair sealing conical surface 14, the interference length L2 is 0mm-3mm, and the interference delta 2 is 0mm-0.6mm.
In the actual use process, after the internal thread 3 of the threaded joint is in threaded connection with the external thread 10, the main sealing spherical surface 5 of the internal thread is in metal interference contact with the main sealing conical surface 12 of the external thread, the interference length L1 is 2mm-4mm, and the interference delta 1 is 0.3mm-0.6mm; the internal thread pair sealing conical surface 7 is in metal interference contact with the external thread pair sealing conical surface 14, the interference length L2 is 0mm-3mm, the interference delta 2 is 0mm-0.6mm, and the sufficient sealing interference length and the contact pressure can ensure the safety and reliability of the sealing performance of the threaded joint under the composite loads of stretching/compression, bending, internal pressure/external pressure, impact, fatigue vibration and the like; the main sealing structure is close to the screw thread and far away from the torque shoulder, is a second seal of the joint structure, can avoid damage to the pipe body sealing structure in the detection, transportation, field operation and pipe column service processes, reduces the influence of torque shoulder and end face corrosion on the seal, and enhances the tensile and continuous compression resistance; the auxiliary sealing structure is close to the torque shoulder and is the third sealing of the joint structure, so that the stress concentration at the shoulder position can be greatly reduced, and the auxiliary sealing function can be realized.
Example 6
Preferably, on the basis of embodiment 1 or 2 or 3 or 4 or 5, in this embodiment, preferably, the length of the internal thread relief groove 4 is 5.08mm-10.16mm, and the depth is 1mm-2mm, and the internal thread relief groove 4 cooperates with the external thread transition surface 11 to form the oil storage groove 18, and the taper angle beta of the external thread transition surface 11 ranges from 25 ° to 30 °.
In the actual use process, the length of the internal thread tool withdrawal groove 4 is 5.08-10.16 mm, the depth is 1-2 mm, the processing efficiency can be improved by using multi-tooth tool threads for processing, and in addition, after the internal thread tool withdrawal groove 4 is buckled, the internal thread tool withdrawal groove 4 is matched with the external thread transition surface 11 to form an oil storage groove 18, so that the function of storing redundant thread fat is realized; the cone angle beta of the external thread transition surface 11 ranges from 25 degrees to 30 degrees, and the machining interference of the external thread 10 can be avoided.
Example 7
Preferably, in this embodiment, on the basis of embodiment 1 or 2 or 3 or 4 or 5 or 6, preferably, the torque-resisting shoulder 8 of the coupling and the torque-resisting end face 15 of the pipe body are both negative angles, the shoulder load angle phi 1 and the end face load angle phi 2 are the same, the ranges are 13 ° to 15 °, the torque-resisting end face 15 of the pipe body and the negative sealing conical surface 14 of the external thread adopt arc transition, the radius of the arc is 0.5mm to 1mm, and the main sealing conical surface 12 of the external thread and the transition surface 11 of the external thread adopt arc transition; the anti-torque shoulder 8 of the coupling and the sealing conical surface 7 of the internal thread pair are in arc transition, the radius of the arc is 0.5mm-1mm, and the main sealing spherical surface 5 of the internal thread and the tool retracting groove 4 of the internal thread are in arc transition.
In the actual use process, the torque-resistant shoulder 8 of the coupling and the torque-resistant end face 15 of the pipe body are both in negative angles, the shoulder bearing angle phi 1 and the end face bearing angle phi 2 are the same in degrees and are in the range of 13 degrees to 15 degrees, the structure can ensure the position precision of the make-up and the compression resistance of the joint, and meanwhile, the torque-resistant shoulder 8 of the coupling and the torque-resistant end face 15 of the pipe body are in metal interference contact after the make-up, so that the fourth seal of the coupling can play a role in auxiliary sealing.
Example 8
Preferably, on the basis of embodiment 1 or 2 or 3 or 4 or 5 or 6 or 7, in this embodiment, preferably, the end of the pipe body 2 is subjected to diameter reduction treatment, the diameter reduction length is in the range of 10mm-15mm, the wall thickness is in the range of 0.5mm-0.7mm, the length of the flat cylindrical surface 16 in the pipe end of the pipe body 2 is in the range of 10mm-15mm, and the conical taper angle alpha of the flat conical surface 17 in the pipe end is 5 ° -10 °.
In the actual use process, the end part of the pipe body 2 is subjected to diameter reduction treatment, the diameter reduction length is in the range of 10mm-15mm, the wall thickness is in the range of 0.5mm-0.7mm, the process can increase the thickness of the end face of the pipe body, reduce the ovality of the pipe end, and improve the stretching resistance and the compression resistance of the joint.
Example 9
The structure of the special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance is adopted in the embodiment, and the special threaded oil pipe with the air tightness of N80Q with the material steel grade of phi 88.9 multiplied by 7.34mm is taken as an example, and the sealing performance and the fatigue vibration resistance of the special threaded joint are verified through a high-temperature A series test and a resonance bending fatigue test.
1 high temperature A series test load establishment
The test load of the high-temperature A system is shown in table 1, and the test load is calculated according to the API 5C 5-2017 standard and is calculated by 88.9mm of nominal outer diameter, 7.34mm of nominal wall thickness and 655MPa of measured minimum yield strength.
TABLE 1 high temperature A series test load experiment parameter table
2. Finite element analysis for high temperature A series test
The seal and shoulder stress of the special threaded joint at each load point in the high temperature A series test are shown in fig. 9, the seal contact pressure and contact length of each load point are shown in fig. 10, and the seal contact area of each load point is shown in fig. 11. The finite element analysis result shows that the contact length of the special threaded joint is 2-3mm under the conditions of 10 e-21 e load point high temperature stretching/compression and internal pressure load, the contact pressure is 250-750MPa, the special threaded joint is in a curve with high two sides and low middle, the minimum sealing contact area is more than 7 times of the maximum test internal pressure, and the special threaded joint has good sealing property.
3. Load build-up for resonant bending fatigue test
The resonant bending fatigue test load is shown in table 2.
Table 2 load parameter table for resonant bending fatigue test
4. Resonance bending fatigue test
The loading frequency of the resonance bending fatigue test is 20-30 HZ, the test sample alternating strain loading process is shown in figure 12, and the test result is shown in table 3. As can be seen from Table 3, the special threaded joint has no crack initiation and no leakage when subjected to resonance bending fatigue for 1000 ten thousand times under the conditions of internal pressure of 60MPa and bending degree of 20 degrees/30 m, and the threaded joint has good fatigue vibration resistance.
TABLE 3 results of resonant bending fatigue test
In conclusion, the special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance has good tightness and fatigue vibration resistance, and can solve the problem that the development of an unconventional natural gas well requires the reliability and the sealing structural integrity of threaded connection.
The present invention is not limited to the above-mentioned embodiments, and any changes or substitutions that can be easily understood by those skilled in the art within the technical scope of the present invention are intended to be included in the scope of the present invention.
Claims (7)
1. A special screwed joint of oil pipe with high air tightness and fatigue vibration resistance is characterized in that: the coupling comprises a coupling (1) and a pipe body (2) matched with the coupling (1), wherein an internal thread (3), an internal thread recession (4), an internal thread main sealing spherical surface (5), an internal thread sealing guiding conical surface (6), an internal thread auxiliary sealing conical surface (7), a negative angle torque shoulder (8) and a coupling middle hole (9) are sequentially arranged on the coupling (1) along the axial direction, the pipe body (2) is sequentially provided with an external thread (10), an external thread transition surface (11), an external thread main sealing conical surface (12), an external thread sealing guiding conical surface (13), an external thread auxiliary sealing conical surface (14), a pipe body torque-resistant end surface (15), a pipe end internal flat cylindrical surface (16) and a pipe end internal flat surface (17), after the coupling (1) and the pipe body (2) are in threaded connection, the internal thread main sealing spherical surface (5) and the external thread main sealing conical surface (12) are matched to form a main sealing structure, the internal thread sealing guiding conical surface (6) and the external thread sealing guiding conical surface (13) are matched to form a sealing guiding structure, the internal thread auxiliary sealing conical surface (7) and the external thread auxiliary sealing conical surface (14) are matched with the external thread main sealing conical surface (8) to form an interference torque-resistant end surface (15), the tooth top of the internal thread (3) is in interference contact with the tooth bottom metal of the external thread (10), the tooth bottom of the internal thread (3) is separated from the tooth top of the external thread (10), the guide surface of the internal thread (3) is separated from the guide surface of the external thread (10), the bearing surface of the internal thread (3) is in metal contact with the bearing surface of the external thread (10), and the internal thread tool withdrawal groove (4) and the external thread transition surface (11) form an oil storage groove (18).
2. The special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance according to claim 1, wherein the special threaded joint is characterized in that: the internal thread (3) is a coupling buttress thread and comprises a tooth top, a tooth bottom, a guide surface, a bearing surface, an internal thread tooth height (H), an internal thread tooth groove (A1) and an internal thread tooth thickness (A2), wherein the tooth top and the tooth bottom are parallel to the central axis of the coupling (1); the guide surfaces are double-angle combined guide surfaces, the angle (gamma 1) of the first guide surface is 10 degrees to 13 degrees, the angle (gamma 2) of the second guide surface is 30 degrees to 40 degrees, and the height (H) of the second guide surface is 1/3-1/2 of the tooth height H of the internal thread; the negative angle (theta 1) of the internal thread bearing surface is 1-3 degrees; the internal thread tooth height (H) ranges from 1.0mm to 1.2mm; the difference between the tooth groove (A1) of the internal thread and the tooth thickness (A2) of the internal thread is 0.05mm-0.15mm.
3. The special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance according to claim 1, wherein the special threaded joint is characterized in that: the external thread (10) is in a buttress shape and comprises a tooth top, a tooth bottom, a guide surface, a bearing surface, an external thread tooth height (H1), an external thread tooth socket (C2) and an external thread tooth thickness (C1), wherein the tooth top and the tooth bottom are parallel to the central axis of the pipe body (2); the angle (gamma 3) of the external thread guide surface is 10 degrees to 13 degrees; the negative angle (theta 2) of the external thread bearing surface is 1-3 degrees; the tooth height (H1) of the external thread is in the range of 0.9mm-1.1mm; the difference between the tooth groove (C2) of the external thread and the tooth thickness (C1) of the external thread is 0.05m-0.15mm.
4. The special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance according to claim 1, wherein the special threaded joint is characterized in that: the internal thread (3) and the external thread (10) are small taper conical threads, the taper is 1:18, 6 teeth per inch are formed, phosphating or copper plating treatment is carried out on the surface of the internal thread (3), and the interference contact range of the tooth tops of the internal thread (3) and the tooth bottoms of the external thread (10) is 0.05mm-0.15mm.
5. The special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance according to claim 1, wherein the special threaded joint is characterized in that: the radius range of the internal thread main sealing spherical surface (5) is 50mm-70mm, and the length range is 3.5mm-4mm; the angle range of the internal thread sealing guide conical surface (6) is 2-4 degrees, and the length range is 3-4 mm; the angle range of the internal thread pair sealing conical surface (7) is 14-17 degrees, and the length range is 2.7-3.2 mm; the angle range of the main sealing conical surface (12) of the external thread is 9-12 degrees, and the length is 5.3-5.8mm; the angle range of the external thread sealing guide surface (13) is 2-5 degrees, and the length is 2.5-3.5mm; the angle range of the external thread pair sealing conical surface (14) is 11-14 degrees, and the length is 2.3-2.8 mm; after the internal thread (3) is in threaded connection with the external thread (10), the internal thread main sealing spherical surface (5) is in metal interference contact with the external thread main sealing conical surface (12), the interference length (L1) is 2mm-4mm, and the interference magnitude (delta 1) is 0.3mm-0.6mm; the internal thread pair sealing conical surface (7) is in metal interference contact with the external thread pair sealing conical surface (14), the interference length (L2) ranges from 0mm to 3mm, and the interference magnitude (delta 2) ranges from 0mm to 0.6mm.
6. The special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance according to claim 1, wherein the special threaded joint is characterized in that: the coupling torque-resistant shoulder (8) and the pipe body torque-resistant end face (15) are both negative angles, the shoulder bearing angle (phi 1) and the end face negative angle (phi 2) have the same degrees and are in the range of 13 degrees to 15 degrees, the pipe body torque-resistant end face (15) and the external thread negative sealing conical surface (14) are in arc transition, the arc radius is 0.5mm to 1mm, and the external thread main sealing conical surface (12) and the external thread transition surface (11) are in arc transition; the anti-torque shoulder (8) of the coupling and the sealing conical surface (7) of the internal thread pair are in arc transition, the radius of the arc is 0.5mm-1mm, and the main sealing spherical surface (5) of the internal thread and the tool withdrawal groove (4) of the internal thread are in arc transition.
7. The special threaded joint for the oil pipe with high air tightness and fatigue vibration resistance according to claim 1, wherein the special threaded joint is characterized in that: the end part of the pipe body (2) is subjected to diameter reduction treatment, the diameter reduction length is in the range of 10mm-15mm, the wall thickness is in the range of 0.5mm-0.7mm, the length of a flat cylindrical surface (16) in the pipe end of the pipe body (2) is in the range of 10mm-15mm, and the cone angle (alpha) of a flat conical surface (17) in the pipe end is 5-10 degrees.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210326547.5A CN116927674A (en) | 2022-03-30 | 2022-03-30 | Special threaded joint of high-air-tightness and anti-fatigue vibration oil pipe |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202210326547.5A CN116927674A (en) | 2022-03-30 | 2022-03-30 | Special threaded joint of high-air-tightness and anti-fatigue vibration oil pipe |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CN116927674A true CN116927674A (en) | 2023-10-24 |
Family
ID=88391023
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202210326547.5A Pending CN116927674A (en) | 2022-03-30 | 2022-03-30 | Special threaded joint of high-air-tightness and anti-fatigue vibration oil pipe |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN116927674A (en) |
-
2022
- 2022-03-30 CN CN202210326547.5A patent/CN116927674A/en active Pending
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US8678448B2 (en) | Threaded connection | |
| AU2010321285B2 (en) | Threaded connection | |
| JP4535064B2 (en) | Threaded joints for steel pipes | |
| EP0104720B1 (en) | Tubular connection | |
| US9057464B2 (en) | Threaded pipe connector | |
| JP4111386B2 (en) | Fatigue resistant screw elements for threaded pipe joints | |
| CA2678604C (en) | A tight threaded joint of oil field pipes | |
| CN201377293Y (en) | Screwed nipple for air-seal oil pipe | |
| CN103527110A (en) | Multistage sealing anti-sticky buckle type thread for titanium alloy oil casing | |
| CN103628827A (en) | Anti-bonding three-stage end surface metal sealing threaded connector for titanium alloy pipe | |
| JP2705505B2 (en) | Threaded fittings for oil country tubular goods | |
| WO2016113790A1 (en) | Threaded pipe joint | |
| CN116927674A (en) | Special threaded joint of high-air-tightness and anti-fatigue vibration oil pipe | |
| CN217558270U (en) | Oil pipe threaded joint for unconventional natural gas well | |
| CN110529055A (en) | A kind of high antitorque air-tight oil casing nipple | |
| CN113048297B (en) | Threaded joint for pipe | |
| CN116927676A (en) | High anti moment of torsion of oil casing, high metal self sealss screwed joint structure | |
| CN113279704A (en) | Oil casing joint and oil casing assembly | |
| CN108301786B (en) | Special thread-locking joint | |
| CN114320175B (en) | Quick screwing-up threaded joint for anti-sticking | |
| CN108952595B (en) | Air-tight seal threaded joint | |
| CN221442513U (en) | Direct-connection type large-pitch special threaded connection structure | |
| CN219932091U (en) | High-performance oil casing pipe with inner and outer multistage metal sealing structure | |
| CN221169467U (en) | Threaded joint with high sealing performance | |
| CN211397489U (en) | High-strength buckle-changing quick drilling tool joint |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination |