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
  • E21B17/20—Flexible or articulated drilling pipes, e.g. flexible or articulated rods, pipes or cables
• • 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
  • F16L11/00—Hoses, i.e. flexible pipes

Definitions

• the subject disclosure generally relates to methods and apparatus for moving a rod or pipe through a cylinder. Some embodiments relate to the field of coiled tubing and coiled tubing applications in hydrocarbon wells. The subject disclosure also relates to increasing the reach of coiled tubing by delaying the onset of buckling, although it is not limited thereto.
• Coiled tubing refers to metal piping, used for interventions in oil and gas wells and sometimes as production tubing in depleted gas wells, which comes spooled on a large reel. Coiled tubing operations typically involve at least three primary components.
• the coiled tubing itself is disposed on a reel and must, therefore, be dispensed onto and off of the reel during an operation.
• the tubing extends from the reel to an injector.
• the injector moves the tubing into and out of the wellbore.
• a tubing guide or gooseneck Between the injector and the reel is a tubing guide or gooseneck.
• the gooseneck is typically attached or affixed to the injector and guides and supports the coiled tubing from the reel into the injector.
• the tubing guide is attached to the injector at the point where the tubing enters. As the tubing wraps and unwraps on the reel, it moves from one side of the reel to the other (side to side).
• Residual bend exists in every coiled tubing string.
• a coiled-tubing string is plastically deformed (bent) as it is spooled on a reel.
• the tubing is unspooled (bent) from the reel and bent on the gooseneck before entering into the injector and the wellbore.
• Residual bending is one of the technical challenges for coiled tubing operations and originates from the spool of the coiled tubing on the reel.
• the reel is manufactured in a diameter as large as possible to decrease the residual bending incurred on the coiled tubing, the maximum diameter of many reels is limited to several meters due to storage and transportation restrictions.
• Coiled tubing is susceptible to a condition known as helical buckling of the tubing which leads to lockup. Residual bending of the coiled tubing increases the susceptibility of the coiled tubing to helical buckling and lockup. As the coiled tubing goes through the injector head, it passes through a straightener; but the tubing retains some residual bending strain. That strain gives the tubing a helical form when deployed in a wellbore and can cause it to wind axially along the wall of the wellbore like a long, stretched spring.
• the subject disclosure relates to methods of delaying the onset of buckling in an elongated structure having an outer surface traversing a tubular path having an inner surface.
• the method comprises adapting at least one of the outer surface of the elongated structure and the inner surface of the tubular path to increase a coefficient of friction between the outer surface of the elongated structure and the inner surface of the tubular path in a first direction, while maintaining or decreasing a coefficient of friction between the outer surface of the elongated structure and the inner surface of the tubular path in a second direction; and inserting said elongated structure into the tubular path.
• the subject disclosure relates to an apparatus wound about a reel and for use in a tubular path.
• the apparatus comprises a hollow pipe wound about the reel to form a coiled tubing, said pipe when unwound from the reel having a length of at least 1000 feet, an outer diameter of between .75 inches and 5.0 inches, and adapted to have at least one of (i) an anisotropic bending stiffness, and (ii) an outer surface adapted to increase a coefficient of friction between the outer surface and an inner surface of the tubular path in a first direction while maintaining or decreasing a coefficient of friction between the outer surface of and the inner surface of the tubular path in a second direction.
• FIG.l is a graph of axial load as a function of measured depth for a coiled tubing
• FIG. 2 is a graph of axial load as function of measured depth for a coiled tubing which is approaching a locked up state
• FIG. 3 illustrates a coiled tubing with a patterned surface
• FIG. 4 illustrates a modified inner surface of a casing
• FIGS. 5A and 5B illustrate cross-sections of a coiled tubing having an anisotropic cross- section
• FIG. 6 illustrates one topology for creating anistropic stiffness in a coiled tubing
• FIG. 7 illustrates another topology for creating anistropic stiffness in a coiled tubing
• FIGS. 8A and 8B illustrate cross-sections of a strip of varied cross-sectional diameter that may be manufactured into a coiled tubing having anisotropic bending stiffness
• FIGS. 8C and 8D depict a strip that is respectively wound and welded to form a tube
• FIG. 8E depicts a partially cut-away tube formed resulting from the winding and welding of FIGS. 8C and 8D.
• the tubing is stored as a continuous length of pipe wound on a spool.
• the coiled tubing can range from at least one thousand feet long to 15,000 feet long or even greater length.
• the pipe or tube is straightened prior to being translated along the borehole or wellbore (the two being used interchangeably herein) either via gravity or via an injector pushing from a surface. Regardless, the end of the coiled tubing being translated into the borehole is load-free. For an extended reach horizontal wellbore, an axial compressive load will build up along the length of the coiled tubing due to frictional interactions between the coiled tubing and the borehole wall.
• FIG. 1 A typical example of axial load for a pipe as a function of measured depth is plotted in FIG. 1.
• the wellbore in which the pipe having the load depicted in FIG. 1 has a 4000 foot vertical section, a 600 foot transition section (bend) which angles away from the vertical (at a rate of about 15° per 100 feet), and then a horizontal section that remains generally horizontal until the end of the wellbore.
• the first 3200 feet of the tube is in tension (load greater than zero), and the remainder is in compression (load less than zero).
• a first buckling mode is referred to as "sinusoidal buckling".
• the tubing snakes along the bottom of the borehole with curvature in alternating senses. This is considered to be a fairly benign buckling mode, in that neither the internal stresses nor the frictional loads increase significantly.
• the coiled tubing will buckle in a second buckling mode referred to as “helical buckling”. This mode involves the tubing spiraling or wrapping along the borehole (wellbore) wall.
• this helical buckling occurs at a predictable axial load and wavelength.
• the normal force exerted by the borehole wall on the tubing increases very quickly and this buckling may have quite severe consequences.
• helical buckling causes a proportional increase in frictional loading, which in turn creates an increase in axial compressive load.
• the axial compressive load increases very quickly to a level such that the tubing can no longer be pushed into the hole. This condition is termed "lock-up".
• FIG. 2 depicts a plot of axial load as a function of measured depth for an example coiled tubing which is at or almost at a locked up state in the wellbore described before with respect to FIG. 1 (4000 feet vertical section, followed by a transition section of 600 feet, followed by a horizontal section).
• FIG. 2 it is seen that the tubing extends over 9000 feet into the wellbore and it can be deduced from the slope of the curve that the tubing at the transition from the 600 foot transition section to the horizontal section is buckling. As seen in FIG. 2, almost the entire length of tubing is under compression.
• the onset of buckling of a tubing can be delayed by providing the tubing with certain frictional attributes.
• embodiments of the subject disclosure relate to providing the coiled tubing and/or a casing in a wellbore with a modified surface(s) that increase(s) the lateral friction coefficient between the tubing and the casing while maintaining a low axial friction coefficient therebetween.
• the surface of a coiled tubing string is modified from a standard smooth cylindrical form that yields an isotropic frictional resistance in order to increase the frictional resistance to lateral motion while maintaining the low frictional resistance to axial motion.
• FIG. 3 depicts one manner of achieving this anisotropic frictional resistance.
• tube 10 is provided with an outer surface 12 that is patterned such that there are axial "rails" 14 that run along the length of the tube.
• FIG. 3 depicts the rails being triangular in cross- section and drawn as macroscopic features (on the millimeter level). However, much smaller length scales are also contemplated, in non-limiting examples, micron or nanometer scale. In addition, differently shaped cross-sections could be used.
• These rails 14 allow the tubing 10 to slide easily in the axial direction, but will provide enhanced resistance to lateral sliding motion. This enhanced resistance to lateral sliding motion will serve to delay the onset of buckling. It will be appreciated that in one embodiment, the rails 14 are not longitudinally continuous.
• the rails 14 on the outer surface 12 of tube 10 are integral with the tube 10 itself.
• the rails 14 are provided on a thin sleeve provided around and affixed to the outer surface 12 of the tube 10. The thin sleeve may completely cover the outer surface 12 or may provide a partial patterned cover affixed to the outer surface 12.
• independently provided rails 14 are attached to the outer surface 12 of the tube.
• the rails 14 are adapted to permit the tubing 10 to slide easily in the axial direction, but to provide enhanced resistance to lateral sliding motion.
• the surface of the wellbore casing is modified to increase the lateral frictional resistance.
• a wellbore casing 50 is provided with an inner surface 52 that is patterned with axial "rails" 54 that run along the length of the wellbore casing.
• These rails 54 allow a standard smooth cylindrical tubing (not shown) to move in an axial direction with low frictional resistance while providing increased frictional resistance to lateral motion.
• the rails are depicted as being triangular in cross-section and drawn as macroscopic features, but much smaller length scales are contemplated. In addition, differently-shaped cross-sections could be used.
• the rails 54 on the inner surface 52 of casing 50 are integral with the casing 50 itself.
• the rails 54 are provided with a thin sleeve provided around and affixed to the inner surface 52 of the casing 50. The thin sleeve may completely cover the inner surface 52 or may provide a partial patterned cover affixed to the inner surface 52.
• independently provided rails 54 are attached to the inner surface 52 of the casing.
• the rails 54 are adapted to permit a tube to slide easily in the casing 50 in an axial direction, but to provide enhanced resistance to lateral sliding motion.
• both the tubing 10 and casing surface 50 could be modified in a complementary fashion in order to further enhance the resistance to lateral sliding motion.
• the tubing 10 shown in FIG.3 were placed inside the casing 50 shown in FIG. 4, the resulting combination would display a large resistance to lateral sliding motion.
• the onset of helical buckling may be delayed through modification of the bending stiffness of a tubing cross-section. More particularly, onset of buckling may be delayed through the use of tubing having anisotropic bending stiffness.
• Bending stiffness may be made anisotropic by appropriate design of the cross-section of the tubing.
• the cross-section of the tubing may be designed to be nonsymmetrical (i.e., anisotropic), thereby permitting the tubing to bend more easily about one axis versus another.
• Helical buckling of an isotropic tube or cylindrical assembly occurs at a predictable level of axial compressive level and at a predictable wavelength or "natural wavelength".
• a delay occurs in the development of helical buckling, thus allowing further reach of a cylindrical assembly such as a tubing string.
• Embodiments of the subject disclosure comprise methods for providing a coiled tubing string that delays the onset of helical buckling.
• a tube 110 has an anisotropic cross-section 110a at one location as seen in FIG. 5 A.
• An anisotropic cross-section will have different bending stiffness when bending in different directions.
• the cross-section 110a of tube 110 depicted in FIG. 5A will bend more easily about axis 2-2 than 1- 1.
• the cross-section of tube 110 is shown with a circular outer surface 112 and an oval inner surface 114.
• the orientation of the anisotropy can vary along the length of tube.
• FIG. 5B illustrates a cross-section 110b taken further along the length of tube 110 of Fig. 5A with a different orientation.
• FIG. 5B depicts an orientation which is a 90° rotation of the orientation in FIG. 5A.
• Spatial implementation may take a variety of forms, in non-limiting examples, these include varying smoothly, having a characteristic wavelength, random orientation or "jumps" in orientation. Any and all combinations of these spatial variations are contemplated and may suppress the onset of helical buckling.
• the spatial variation can be tailored to a particular coiled tubing dimension and borehole diameter range so as to maximally delay the onset of helical buckling.
• FIG. 6 a cross-section of tube 120 is shown where the outer wall surface 122 is non-concentric with the inner wall surface 124 of tube 120, thereby providing tube 120 with an anisotropic cross-section.
• FIG. 7 a cross-section of tube 130 is shown where the inner wall surface 134 is centrally located, but the outer wall 132 of tube 130 is oval in shape, thereby providing tube 130 with an anisotropic cross-section.
• the coiled tubing string will be under a state of torsion. This will tend to cause helical buckle in which the spiral wraps in one sense.
• a spatial distribution of the anisotropy which spirals in an opposite sense to this torsion sense may delay the onset of helical buckling.
• manufacturing of coiled tubing generally involves making a longitudinal weld along a uniform flat strip.
• the uniform flat strips are welded together with a bias weld to prepare the final flat strip.
• the final flat strip is then rolled and a longitudinal weld is manufactured making a tube of uniform outer diameter and inner diameter except for transition zones at bias weld where there may be a change from one uniform inner diameter to another uniform inner diameter.
• the manufacture of the coiled tubing with anisotropic bending stiffness may involve the rolling of a strip having a non-uniform wall thickness (e.g., such as seen in FIG. 8A) into a tube having a uniform outer diameter and performing a longitudinal seam weld.
• the manufacture of the coiled tubing with anisotropic bending stiffness may involve the rolling of a strip having a non-uniform wall thickness (e.g., such as seen in FIG. 8A) into a tube having a uniform inner surface diameter and performing a longitudinal seam weld. In both cases, the resulting tube will have an anistropic bending stiffness.
• the manufacture of the coiled tubing with anisotropic bending stiffness may involve rolling a strip of material whose cross-sections change along the length of the strip and performing a longitudinal seam weld.
• the cross-section at a location by way of example only one foot away, might have transitioned to having the thickness being largest at the ends and smallest at the middle as seen in FIG. 8B. Effectively, looking lengthwise, the strip would appear to have a helical pattern to its thickness.
• the manufacture of the coiled tubing with anisotropic bending stiffness may involve coiling a strip at an angle as depicted in FIG. 8C, and welding the strip as depicted in FIG. 8D along a helix resultingly formed at adjacent edges of the strip to provide a tube as depicted in FIG. 8E.
• the resulting tube may be coiled as desired.
• the weld itself may introduce the anisotropy to the tube, or the strip might have a varied thickness that introduces anisotropy.
• the pipe diameter is between 0.75 inches and 5 inches in outer diameter) and is spooled on a reel (as seen in FIG. 8D), and the pipe length when unspooled is at least one thousand feet long.
• the pipe has either an anisotropic bending stiffness, or an outer surface adapted to increase a coefficient of friction between its outer surface and an inner surface of a tubular path into which it is to be inserted in a first direction while maintaining or decreasing a coefficient of friction between its outer surface and the inner surface of the tubular path in a second direction.
• Non-limiting examples include optic cables, wireline cables, and slickline cables which may be inserted into various cylindrical assemblies, in non-limiting examples, coiled tubing or a wellbore.
• Non-oilfield applications include the use of embodiments of the subject disclosure in the medical field, non-limiting examples, include applications of stents and other medical devices.
• tubular path may be an uncased wellbore (borehole).
• a hollow structure pipe
• any elongated structure typically having a length at least 1000 times its width
• an elongated solid structure may be unwound and inserted into a tubular path. Accordingly, such modifications are intended to be included within the scope of this disclosure as defined in the following claims.

Landscapes

• Engineering & Computer Science (AREA)
• Geology (AREA)
• Life Sciences & Earth Sciences (AREA)
• Mining & Mineral Resources (AREA)
• Mechanical Engineering (AREA)
• General Life Sciences & Earth Sciences (AREA)
• Fluid Mechanics (AREA)
• Environmental & Geological Engineering (AREA)
• Physics & Mathematics (AREA)
• Geochemistry & Mineralogy (AREA)
• General Engineering & Computer Science (AREA)
• Rigid Pipes And Flexible Pipes (AREA)
• Shaping Of Tube Ends By Bending Or Straightening (AREA)
• Physical Or Chemical Processes And Apparatus (AREA)
• Earth Drilling (AREA)

Priority Applications (4)

Applications Claiming Priority (6)

Publications (1)

Family

ID=47752247

Family Applications (1)

Country Status (6)

Families Citing this family (3)

Citations (4)

Family Cites Families (15)

• 2012
  • 2012-06-05 US US13/488,957 patent/US20130056225A1/en not_active Abandoned
  • 2012-06-15 RU RU2014112714/03A patent/RU2605104C2/ru not_active IP Right Cessation
  • 2012-06-15 MX MX2014002388A patent/MX2014002388A/es not_active Application Discontinuation
  • 2012-06-15 EP EP12828805.7A patent/EP2734701A4/en not_active Withdrawn
  • 2012-06-15 BR BR112014004938A patent/BR112014004938A2/pt not_active IP Right Cessation
  • 2012-06-15 WO PCT/US2012/042571 patent/WO2013032560A1/en active Application Filing

Patent Citations (4)

Non-Patent Citations (1)

Also Published As

Similar Documents

Legal Events