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
  • 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
  • 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
  • F16L15/06—Screw-threaded joints; Forms of screw-threads for such joints characterised by the shape of the screw-thread

Definitions

• the claimed invention refers to sealed threaded casing pipes joints and can be applied for joining of the casing string elements used in construction and operation of gas and oil wells.
• Gas and oil well casings are operated under complicated conditions in aggressive media and under sufficient multidirectional mechanical loads. Due to the abovementioned the major requirements to the casing are its durability at multiple makes-up and breaks-out and within long operation, and preservation of high sealability under high mechanical loads.
• the threaded casing pipes joint described in the document (1) has a following shortage: poor make-up features - complicated inspection of the given interference and torque values during make-up process.
• the difficulty with appropriate interference value set up results in not shouldered or over torqued state of the joint.
• the joint which is not shouldered loses its sealability sufficiently.
• the intercontacting surfaces might get injured, which results in decrease of the joint durability at its multiple makes and breaks;
• the given joint doesn't ensure flushness of the casing string which prevents from free of jamming passing of the underground equipment down the hole during the process of construction and operation of the well, and results in flow disturbance of the machining medium passing inside the string which creates high pressure local zones.
• the given engineering solution (1) is taken as a nearest analogue of the claimed invention.
• the claimed invention is targeted at creation of the threaded casing pipes joint with high sealabiiity features, improved make-up specifications and flushness providing simplicity of its manufacture, operation and possibility to make-up the given joint with other joints with buttress trapezoidal tapered threads like Buttress, OTTM, OTTG, VARM without crossovers.
• Sealed threaded casing pipes joint consists of the male and female elements with the trapezoidal tapered threads with 1 :16 taper performed correspondingly on the external and internal surfaces of its ends.
• Load flank inclination angle of the thread profile of the male and female elements is 2 - 4° to the thread axes normal line
• lead-in flank inclination angle of the thread profile is 9 - 1 1° to the thread axes normal line.
• the joint is performed with inner sealing unit, made by intercontacting bearing end surfaces produced on the male and female elements and located perpendicularly to the thread axis line.
• the bearing end length of the male element is 6,9 - 100,3 mm.
• FIG. 1 shows made-up threaded casing pipes joint and thread profile.
• Figure 2 shows made-up threaded casing pipes joint and inner sealing unit.
• Sealed threaded casing pipes joint consists of the male (2) and female (1) elements with the trapezoidal tapered threads (3) performed correspondingly on the external and internal surfaces of its ends.
• the trapezoidal tapered threads (3) on the male (2) and female (1) elements are performed with 1 :16 taper. Performance of the threads (3) with 1 : 16 taper provides for high level of locking mating engagement in a shouldered state and for possibility of optimal taking by the joint of bending and tensile loads affecting it during its operation.
• Lead-in flank (6) inclination angle of the thread (3) profile of the male (2) and female (1) elements is 2 - 4° to the thread axes normal line
• load flank (7) inclination angle of the thread (3) profile is 9 - 1 1° to the thread axes normal line.
• the thread axes normal line is a determination of a line perpendicular to the thread axis line.
• Performance of the lead-in flank (6) inclination angle of the thread (3) profile equal to 9-1 1° to the thread axes normal line stabilizes the location of the male (2) element relative to the female (1) element at the beginning of make-up process, which prevents the joint from jamming and from appearance of damaging (galling) on the thread (3) surfaces and provides for possibility of multiple makes and breaks of the joint preserving its high sealability properties.
• Performance of the load flank (7) inclination angle of the thread (3) profile equal to 2-4° to the thread axes normal line prevents from thread (3) disengagement under sufficient tensile load (sealability loss) affecting the joint under the weight of the string run in wells.
• Another version of the claimed invention performance is characterized by performance of the lead-in flank (6) inclination angle of the thread (3) profile of the male (2) and female (1) elements equal to 23-25° to the thread axes normal line and performance of the thread profile load flank (7) that can vary from -3 to -5° to the thread axes normal line.
• the thread (3) profile load flank (7) negative inclination angle (-3 to -5°) prevents from disengagement of the male (2) and female (1) elements thread turns under considerable tensile loads. Besides that decrease of the preload value is achieved comparing to constructions of threads with positive load flank inclination angle, which provides for high durability of the joint and improved operational features under high loads.
• Performance of the lead-in flank (6) inclination angle of the thread (3) profile equal to 23-25° to the thread axes normal line makes the joint make-up process easier and increases its durability at multiple makes and breaks.
• the joint is designed with an inner sealing unit (4), formed by intercontacting bearing end surfaces (5).
• the mentioned bearing end surfaces (5) of the male (2) and female (1) elements are located perpendicularly to the thread axis line.
• Presence of the sealing unit (4) of the joint helps to increase its sealability due to bearing end surfaces (5) intercontacting with considerable contact stresses provide for plastic strains appearance on the surfaces (5) and produce a "metal- to-metal" sealing during make-up process, and consequently - high sealability of the joint under multidirectional loads.
• Trapezoidal tapered threads (3) are characterized by absence of the gap on the male (2) and female (1) elements thread profile crests (8) (thread profile is designed equally high).
• the bearing end (L) length of the male (2) element is 6,9 - 100,3 mm.
• the bearing end (L) length is therein a distance from the bearing end face
• male (2) element bearing end length (L) is chosen from the range depending on the gap width ( ⁇ 1) on the thread profile (3) lead-in flank
• the female (1) element Upon demand of GOSTs acting in this pertinent art, the female (1) element shall always be produced of the material with stronger grade than the male (2) element. Therefore all calculations for possible deformations of the bearing end surfaces (5) are made for the male element (2).
• buttress trapezoidal tapered threads (3) have structural gap ( ⁇ 1) on the thread lead-in flanks (6), necessary for easy, free of jamming makeup of this type of threads.
• the gap on the thread lead-in flanks (6) taken out and the lead-in flanks (6) undertake the compression, preventing the male element (2) bearing end surface (5) deformation moving from the area of plastic strain to the area of elastic strain.
• the larger is the gap ( ⁇ 1) on the thread (3) lead-in flanks (6), the larger bearing end length (L) will be required for preventing the male element (2) bearing end surface (5) deformation moving to the area of elastic strain.
• male element (2) bearing end with length (L) less than 6,9 mm will result in male element (2) surface (5) deformation moving from the area of plastic strain to the area of elastic strain, in irreversible male element (2) surface (5) damage, in appearance of galling, which will cause decrease of the joint wear resistance and its sealability decrease.
• the claimed joint consisting of the male and female elements is produced with trapezoidal tapered threads with 1 :16 taper.
• the thread profile load flank inclination angle is 3° to the thread axis normal line and the thread profile lead-in flank inclination angle is 10° to the thread axis normal line.
• the thread lead is 5,08 mm with the thread passage diameter 245 mm and wall thickness 8,94 mm.
• the male element bearing end length is chosen from the range depending on the gap width on the thread profile lead-in flank and on the male element yield point (see table 1 ).
• the claimed joint consisting of the male and female elements is produced with trapezoidal tapered threads (3) with 1 : 16 taper.
• the thread profile load flank inclination angle is -4° to the thread axis normal line and the thread profile lead-in flank inclination angle is 24° to the thread axis normal line.
• the thread lead is 5,08 mm with the thread passage diameter 245 mm and wall thickness 8,94 mm.
• the joint is designed with an inner sealing unit formed by intercontacting bearing end surfaces located perpendicularly to the thread axes line.
• the male element bearing end length is chosen from the range depending on the gap width on the thread profile lead-in flank and on the male element yield point in the same manner as the example 1 (see table 1).

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• Engineering & Computer Science (AREA)
• Life Sciences & Earth Sciences (AREA)
• Geology (AREA)
• Mining & Mineral Resources (AREA)
• Mechanical Engineering (AREA)
• Physics & Mathematics (AREA)
• Environmental & Geological Engineering (AREA)
• Fluid Mechanics (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Geochemistry & Mineralogy (AREA)
• Earth Drilling (AREA)
• Mutual Connection Of Rods And Tubes (AREA)

Priority Applications (1)

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Publications (2)

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Cited By (2)

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• 2012
  • 2012-12-13 RU RU2012153851/06A patent/RU2504710C1/ru active
• 2013
  • 2013-12-03 WO PCT/RU2013/001085 patent/WO2014092605A2/en active Application Filing
  • 2013-12-03 EA EA201500518A patent/EA031821B1/ru active IP Right Revival

Non-Patent Citations (1)

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