Patent Publication Number: US-2003233880-A1

Title: Ultrasonic tubular inspection apparatus having fluid interface and system and method incorporating same

Description:
FIELD OF THE INVENTION  
       [0001] The present technique relates generally to tubular inspection systems and, more particularly, to ultrasonic tubular inspection techniques for various tubular goods, such as oil country tubular goods (OCTG). The present technique provides a system and method for ultrasonically testing a tubular good through a fluid interface between the tubular good and ultrasonic transducers, which are movable along the tubular good.  
       BACKGROUND OF THE INVENTION  
       [0002] Tubular goods are used in a variety of industrial applications, which may be particularly sensitive to internal defects. For example, a particular tubular good may have internal-external thickness variations, hairline fractures, seams, and various other longitudinally-oriented, transversely-oriented, and obliquely-oriented defects, which may be undetectable by alternative inspection techniques. These defects may arise during the initial manufacturing process, the subsequent processing or transportation, or they may occur as service-induced defects. In many industrial applications, the foregoing defects may lead to environmental damage, bodily injury, equipment damage and downtime, and loss of the associated product, such as hydrocarbon reserves.  
       [0003] Ultrasonic testing has been found to be particularly useful in detecting the foregoing defects, and in certain instances, ultrasonic testing provides the only detection mechanism for such defects. A variety of ultrasonic testing systems currently exist for testing tubular goods following manufacture and other processing stages. Each of these ultrasonic testing systems performs an ultrasonic examination in a helical scanning pattern about the surface of the tubular good. In fluid immersion systems, the tubular good is moved rotationally and longitudinally through a fluid bath, where a number of ultrasonic transducers reside. Although the fluid medium provides relatively low signal degradation from the ultrasonic transducers, these fluid immersion systems are cumbersome and difficult to use in pinpointing defects due to the size and momentum of the tubular goods. In rotating head systems, an assembly of ultrasonic transducers is rotated at high speeds about a tubular good, which is moved longitudinally through the rotating head assembly. Again, the size and momentum of the tubular good complicates the pinpointing of defects within the tubular good.  
       [0004] In other systems, the ultrasonic transducers are mounted in a contoured solid material, such as polystyrene or Lucite, which is moved along the rotating tubular good. In a different application, the ultrasonic transducers may be mounted in a rubber or polystyrene wheel. Both of these systems have a relatively lower sensitivity due to the use of an additional solid interface between the tubular good and the ultrasonic transducers. Moreover, the solids may have defects, such as scratches, which further reduce the ultrasonic sensitivity. These solid-interface systems also have other drawbacks, such as the inability to focus the ultrasonic beams, the relatively narrow inspection width of the rubber wheel system, and the consumability of the polystyrene shoe system.  
       [0005] Accordingly, a technique is needed for ultrasonically testing a tubular good using a movable ultrasonic test assembly having a fluid interface.  
       SUMMARY OF THE INVENTION  
       [0006] The present technique provides a system and method for ultrasonically testing a tubular good through a fluid medium using a movable ultrasonic test assembly. The movable ultrasonic test assembly has a fluid chamber, which is open to an outer surface of the tubular good. Ultrasonic transducers are mountable in the movable ultrasonic test assembly, such that ultrasound waves are transmittable through fluid between the tubular and the ultrasonic transducers. The movable ultrasonic test assembly also may have a removable interface structure, which serves as a replaceable wear surface for movably supporting the ultrasonic test assembly on the outer surface of the tubular. A variety of positioning and control system also may be provided to perform an ultrasonic test of the tubular. For example, the positioning and control system may have drive assemblies for rotating the tubular and moving the ultrasonic test assembly along the tubular. 
     
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
     [0007] Exemplary embodiments will hereafter be described with reference to the accompanying drawings, wherein like reference numerals denote like elements, and:  
     [0008]FIG. 1 is a diagram of an exemplary ultrasonic test system of the present technique;  
     [0009]FIG. 2 is a perspective view of an exemplary ultrasonic test assembly of the system illustrated by FIG. 1;  
     [0010]FIG. 3 is a side view of an exemplary ultrasonic transducer unit for the ultrasonic test assembly illustrated by FIG. 2;  
     [0011]FIG. 4 is top view of the ultrasonic test assembly illustrating a plurality of differently oriented receptacles for the ultrasonic transducer unit illustrated by FIG. 3;  
     [0012]FIG. 5 is an end view of the ultrasonic test assembly top-mounted to a tubular illustrating transverse ultrasonic testing in opposite directions around the circumference of the tubular good;  
     [0013]FIG. 6 is a side view of the ultrasonic test assembly top-mounted to the tubular good illustrating longitudinal ultrasonic testing in opposite directions along the longitudinal axis of the tubular good; and  
     [0014]FIGS. 7 and 8 are side and bottom views of the ultrasonic test assembly illustrating a removable contact member disposed on an interface structure of the ultrasonic test assembly. 
    
    
     DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS  
     [0015] As described in detail below, the present technique provides a system and method for ultrasonically testing a tubular good using a movable ultrasonic test assembly having a fluid interface between the tubular good and ultrasonic transducers. The fluid interface provides relatively strong signal transmission to the tubular good, while the movability of the ultrasonic test assembly avoids the cumbersome movement of large tubular goods. Accordingly, the movability of the ultrasonic test assembly allows rapid return of the ultrasonic transducers to a potential flaw, rather than requiring movement of the tubular good back to the flaw. The ultrasonic transducers may be disposed in a variety of normal-flaw-detection, transverse-flaw-detection, longitudinal-flaw-detection, and oblique-flaw-detection orientations in one or multiple directions, such as left/right and clockwise/counterclockwise directions. Moreover, the ultrasonic transducers may have curved lenses, such as spherical or cylindrical lenses, to focus the ultrasound (e.g., more collimated ultrasound) for better detection of defects and less signal degradation due to the curved surface of the tubular good. The movable ultrasonic test assembly of the present technique also has a removable contact member, which makes the assembly a non-consumable item that endures repeated use by replacing the removable contact member after a degree of wear.  
     [0016]FIG. 1 is a diagram illustrating an exemplary ultrasonic test system  10  having an ultrasonic test assembly  12  of the present technique. As illustrated, the ultrasonic test assembly  12  is movably coupled to a tubular good  14 , which may comprise oilfield casing, tubing, drill pipe, line pipe, or a variety of other oilfield or other industrial tubular goods. The ultrasonic test system  10  also comprises an ultrasonic test control system  16 , which is communicatively coupled to a fluid supply system  18  and a positioning system  20 . The fluid supply system  18  feeds a desired fluid, such as water, to the ultrasonic test assembly  12  to maintain a fluid interface between ultrasonic transducers and a top surface of the tubular good  14 . The positioning system  20  is communicatively coupled to an axial drive assembly  22  for the ultrasonic test assembly  12 , such that the ultrasonic test assembly  12  is longitudinally movable along the tubular good  14  during an ultrasonic test sequence. The positioning system  20  is also communicatively coupled to a rotational drive assembly  24 , which rotates the tubular good  14  during the ultrasonic test sequence. Alternatively, the ultrasonic test assembly  12  may have a longitudinal and rotational drive assembly, which allows movement of the test unit  12  along and around tubular good  14  to minimize movement of the bulky tubular good  14  during ultrasonic testing. In operation, the ultrasonic test control system  16  may execute a helical test routine  26  to move the ultrasonic test assembly  12  and rotate the tubular good  14 , such that ultrasonic transducers in the unit  12  traverse the tubular good  14  in a helical test pattern. The ultrasonic test control system  16  also may comprise an ultrasound analysis routine  28  for evaluating ultrasound reflections and identifying defects in the tubular good  14 . The ultrasonic test system  10  also may comprise a variety of other hardware and software within the scope of the present technique.  
     [0017]FIG. 2 is a perspective view of an exemplary embodiment of the ultrasonic test assembly  12  top-mounted to the tubular good  14 . As illustrated, the ultrasonic test assembly  12  has a fluid chamber  30  disposed between a mount interface  32  and a pair of transducer mount panels  34  and  36 . The illustrated fluid chamber  30  is open at a top opening  38  between the transducer mount panels  34  and  36  and is fillable via a fluid inlet  40 . However, the fluid chamber  30  may comprise any suitable fluid retention structure and filling mechanism. For example, the fluid chamber  30  may comprise a pressurized fluid chamber to allow positioning of the ultrasonic test assembly  12  at any position around the tubular good  14 . The mount interface  32  is substantially sealable against a top surface  42  of the tubular good  14 , such that fluid is substantially retained within the fluid chamber  30  in fluid contact with the top surface  42  and ultrasonic transducers disposed within the transducer mount panels  34  and  36 . As illustrated, the transducer mount panels  34  and  36  have ultrasonic transducer units  44 - 84  disposed in transducer mount receptacles, which may be in transverse, longitudinal, perpendicular, or oblique testing orientations in one or more directions relative to the tubular good  14 .  
     [0018] Each of the ultrasonic transducer units  44 - 84  also may comprise a variety of ultrasonic transducer elements, lenses, and circuitry to transmit a desired ultrasonic beam and interpret an ultrasonic echo reflected back from a defect. For example, the ultrasonic transducer units  44 - 84  may comprise a piezoelectric element and a lens, such as a flat, cylindrical, or spherical lens. The curved lenses accommodate the curved surface of the tubular good  14  to minimize the loss of incident sound energy on the curved surface of the tubular good  14 . In operation, the cylindrical lens focuses sound energy to a line and the spherical lens focuses sound energy to a spot. FIG. 3 is a side view of an exemplary line-focused ultrasonic transducer unit  86 , which has a cylindrical lens  88  and an internal piezoelectric element  90  for transmitting and receiving ultrasounds. Accordingly, the ultrasonic test assembly  12  of the present technique may use spot-focused or line-focused ultrasonic transducer units to provide more accurate detection of internal defects.  
     [0019] The ultrasonic test assembly  12  also may position the ultrasonic transducer units  44 - 84  in a variety of detection orientations and directions. FIG. 4 is a top view of the ultrasonic test assembly  12  having a plurality of transducer mount receptacles  91  disposed in the transducer mount panels  34  and  36 . As illustrated, the transducer mount receptacles  91  are disposed in perpendicular angles, longitudinally-oriented angles, transversely-oriented angles, and obliquely-oriented angles to detect perpendicular defects, transverse defects, longitudinal defects, and oblique defects, respectively. The foregoing defects are detected by positioning the ultrasonic transducer units  44 - 84  at an incident angle in the fluid within the fluid chamber  30 , such that the ultrasonic transducer units  44 - 84  generate a shear wave mode in the tubular good  14  at, for example, an angle of approximately 45 degrees. For transverse flaw detection, an exemplary incident angle is approximately 17 degrees. The incident angles for longitudinal and oblique flaw detection varies depending on the curve of the tubular good  14 . The transducer mount receptacles  91  are also staggered to provide for a complete coverage of the tubular good  14  during the ultrasonic inspection. In this exemplary embodiment, the transducer mount receptacles  91  may be configured for a 30 percent overlap of the mounted ultrasonic transducer units  44 - 84 .  
     [0020] In the illustrated embodiment of FIG. 4, the transducer mount receptacles  91  comprise a normal-detection receptacle  92 , transverse-detection receptacles  94  and  96 , and longitudinal-detection receptacles  98  and  100 . The normal-detection receptacle  92  is oriented normal to the curved surface of the tubular good  14  to direct sound waves perpendicularly into the tubular good  14 . These normally-directed sound waves detect wall thickness variations in the tubular good  14 . The transverse-detection receptacles  94  and  96  are angled along the axis of the tubular good  14  to direct sound waves from a mounted ultrasonic transducer unit longitudinally along the tubular good  14 . These longitudinally directed sound waves detect transverse flaws within the tubular good  14 . As noted above, the transverse-detection receptacles  94  and  96  are disposed at an incident angle of 17 degrees. The transverse-detection receptacles  94  and  96  also may be disposed in different directions, such as leftward and rightward directions, relative to the tubular good  14 .  
     [0021] The longitudinal-detection receptacles  98  and  100  are angled circumferentially about the tubular good  14  to direct sound waves from a mounted ultrasonic transducer unit around the circumference of the tubular good  14 . These circumferentially or transversely directed sound waves detect longitudinal flaws within the tubular good  14 . Again, the longitudinal-detection receptacles  98  and  100  may be disposed in different directions, such as clockwise and counterclockwise directions, relative to the tubular good  14 . For example, the off-center positioning of the transducer mount panels  34  and  36  may facilitate multi-directional ultrasonic testing in the various testing orientations. The foregoing multi-directional positioning is discussed in further detail below with reference to FIGS. 5 and 6.  
     [0022] If oblique-flaw detection is desired, then a variety of oblique-detection receptacles may be disposed within the ultrasonic test assembly  12 . The transducer mount receptacles  91  illustrated by FIG. 4 comprise oblique-detection receptacles  102 - 116  and  118 - 132 , which are disposed in transducer mount panels  34  and  36 , respectively. The oblique-detection receptacles  102 ,  104 ,  106 , and  108  are obliquely-oriented for detection of oblique-flaws at exemplary angles of 12, 22.5, 45, and 67 degrees in a leftward clockwise direction relative to the tubular good  14 . In this same example, the oblique-detection receptacles  110 ,  112 ,  114 , and  116  are obliquely-oriented for detection of oblique-flaws at exemplary angles of 12, 22.5, 45, and 67 degrees in a rightward clockwise direction relative to the tubular good  14 . The oblique-detection receptacles  118 ,  120 ,  122 , and  124  are obliquely-oriented for detection of oblique-flaws at exemplary angles of 12, 22.5, 45, and 67 degrees in a leftward counterclockwise direction relative to the tubular good  14 . The oblique-detection receptacles  126 ,  128 ,  130 , and  132  are obliquely-oriented for detection of oblique-flaws at exemplary angles of 12, 22.5, 45, and 67 degrees in a rightward counterclockwise direction relative to the tubular good  14 . Again, an incident angle is selected to generate an exemplary  45  degree shear wave in the tubular good  14  for each of the foregoing oblique-detection receptacles.  
     [0023]FIGS. 5 and 6 illustrate sound wave transmission through the tubular good  14  between inner and outer surfaces  133  and  135  in multiple directions oriented to detect transverse and longitudinal flaws, respectively. FIG. 5 is an end view of the ultrasonic test assembly  12  top-mounted to the tubular good  14  illustrating the operation of transversely-oriented ultrasonic transducer units  134  and  136 , which are disposed in the transducer mount panels  34  and  36 , respectively. As illustrated, the transversely-oriented ultrasonic transducer units  134  and  136  transmit ultrasounds  138  and  140  through fluid in the fluid chamber  30  at the appropriate incident angle, into the tubular good  14  at an angle of approximately 45 degrees, and around the circumference of the tubular good  14  in clockwise and counterclockwise directions, respectively. Again, the ultrasounds  138  and  140  may be spot-focused or line-focused by using spherical or cylindrical lenses, respectively. Moreover, the direct fluid interface between the ultrasonic transducer units  134  and  136  and the tubular good  14  provides greater sensitivity and less signal degradation than a solid interface. If a longitudinal flaw exists in the tubular good  14 , then the respective ultrasound  138  or  140  reflects back to the respective ultrasonic transducer unit  134  or  136 . The respective ultrasonic transducer unit  134  or  136  then converts the reflected sound (or echo) into electrical energy, which is used to identify the longitudinal flaw to the ultrasonic test control system  16  illustrated by FIG. 2.  
     [0024]FIG. 6 is a side view of the ultrasonic test assembly  12  top-mounted to the tubular good  14  illustrating the operation of longitudinally-oriented ultrasonic transducer units  142  and  144 , which are disposed in the transducer mount panels  34  and  36 . As illustrated, the longitudinally-oriented ultrasonic transducer units  142  and  144  transmit ultrasounds  146  and  148  through fluid in the fluid chamber  30  at the appropriate incident angle, into the tubular good  14  at an angle of 45 degrees, and longitudinally along the tubular good  14  in rightward and leftward directions, respectively. As discussed above, the present technique improves the sensitivity and reduces signal degradation of the ultrasonic transducer units  142  and  144  by using a direct fluid interface and curved lenses for the transmission of ultrasounds  138  and  140 . If a transverse flaw exists in the tubular good  14  in either the leftward or rightward direction, then the respective ultrasound  146  or  148  reflects back to the respective ultrasonic transducer unit  142  or  144 . The respective ultrasonic transducer unit  142  or  144  then converts the reflected sound (or echo) into electrical energy, which is used to identify the transverse flaw to the ultrasonic test control system  16  illustrated by FIG. 2.  
     [0025] In addition to the fluid interface and curved lenses of the ultrasonic test assembly  12 , the present technique may have a removable seal or gasket for interfacing with the top surface  42  of the tubular good  14 . FIGS. 7 and 8 are end and bottom views of the ultrasonic test assembly  12  illustrating an exemplary removable contact member  150 , which may comprise any suitable material for movably contacting the tubular good  14 . For example, the removable contact member  150  may comprise a low friction or self-lubricating material, such as UHMW, Teflon, or any other suitable long-chain polymer. In operation, the removable contact member  150  slides along the surface of the tubular good  14  and substantially retains fluid within the fluid chamber  30  of the ultrasonic test assembly  12 . The removable contact member  150  may survive a relatively large number of ultrasonic tests, such as 200 tests, depending on the surface conditions of the tubular good  14 , the thickness and substance of the removable contact member  150 , and various other testing conditions. At any time, the removable contact member  150  may be replaced with another removable contact member  150  to refurbish the ultrasonic test assembly  12  or to accommodate a different ultrasonic test, a different tubular good, or any other testing conditions. The removable contact member  150  also allows the ultrasonic test assembly  12  to be formed from any desired material, because the removable contact member  150  interfaces and wears along the tubular good  14  rather than the ultrasonic test assembly  12 . For example, the ultrasonic test assembly  12  may comprise aluminum, nylon, nylatride, Delrin, or any other rigid material.  
     [0026] While the invention may be susceptible to various modifications and alternative forms, specific embodiments have been shown by way of example in the drawings and will be described in detail herein. However, it should be understood that the invention is not intended to be limited to the particular forms disclosed. Rather, the invention is to cover all modifications, equivalents and alternatives falling within the spirit and scope of the invention as defined by the following appended claims.