Conical array ultrasonic testing (UT) for pipe inspections

Abstract

Systems and methods for conical array ultrasonic testing for pipe inspections are presented. In one embodiment, a method for defect inspection includes inserting an ultrasound sensor into a solid structure. The ultrasound sensor includes a conical transducer having a plurality of ultrasound transmitters. The method also includes detecting flaws in a solid structure by ultrasound signals emitted by the ultrasound sensor. An outer surface of the conical transducer is configured to face a segment of the solid structure that is being inspected.

Description

[0001] CONICAL ARRAY ULTRASONIC TESTING (UT) FOR PIPE INSPECTIONS

[0002] CROSS-REFERENCE TO RELATED APPLICATION

[0003] This application claims the benefit ofU.S. Provisional Application No. 63 / 679,025, filed August 2, 2024, the entire disclosure of which is hereby incorporated by reference.

[0004] BACKGROUND

[0005] Steel catenary risers (SCR) connect a deepwater floating or fixed oil production platform with the bottom of the sea. SCR risers are used to transfer fluids like oil, gas, and injection water. A SCR riser can be made of heavy wall steel pipe. Typical wall thickness varies between 0.75" and 2", but other thicknesses are also possible. Fatigue cracks in an SCR generally occur at girth welds that connect the pipe joints.

[0006] Conventional fatigue design philosophy for dynamic risers uses a stress-life (S-N) approach combined with a fatigue safety factor to assess the performance of nominally defect-free pipe girth welds. For deepwater oil and gas applications, pipe girth welds are also routinely inspected during fabrication prior to installation using external automated ultrasonic testing (AUT), which requires a system qualification (or validation) program for each specific project. A fracture mechanics approach, commonly referred to as an Engineering Critical Assessment (ECA), can be used to conservatively calculate circumferential girth weld flaw sizes (internal, external, and embedded) that will not grow to an unsafe size during the design life of the asset. Weld repair criteria (or to put it another way, flaw or defect acceptance criteria) are then developed for identifying and removing flaws during fabncation, by adjusting the ECA results down by the qualified AUT undersizing.

[0007] There is growing demand in the offshore industry to develop a reliable technology for in-service inspection of girth weld flaws (defects) in deepwater risers, to be able to safely manage integrity through asset's full life cycle. Deepwater production risers and export lines are generally considered un-inspectable by current commercially available technology for the detection of circumferential cracks.

[0008] Accurate, easy to deploy and industry accepted In-Line-Inspection (ILI) tools for in-service girth weld inspection on deepwater risers and flowlines are not currently commercially available for small diameter pipes. The development of such technology is particularly challenging for small diameter, heavy wall pipes that are used for deepwater developments, e.g. risers and flowlines with internal diameters (IDs) in the 4 to 8" range and wall thicknesses (WT) up to 2". These inspections could be located several miles away from the host platform. For example, high pressure high temperature flowlines subject to thermal buckling, and previously inspected assets with known girth weld corrosion. Given the planning required for any offshore ILI campaign and the costs associated with shutting the production, performing an ILI of the entire subsea system for corrosion detection and girth weld cracking in a single campaign is considered the best approach.

[0009] In-service girth weld crack detection technology needs to be accurate, reliable, repeatable, and able to differentiate between internal, external, and embedded flaws. Most welds in risers are narrow gap welds (see Figure 1). Another type of weld, the V-groove butt weld, is sometimes also found in a riser (see Figure 2). Some risers have a Corrosion Resistant Alloy (CRA) cladding on the interwall. This extra layer considerably affects ultrasonic inspection.

[0010] Accordingly, improved techniques and methods to obtain more precise and more reliable estimates of the cracks in the pipes are still needed.

[0011] SUMMARY

[0012] This summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This summary is not intended to identity' key features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter.

[0013] Briefly, embodiments of the present technology are directed to the inspection of pipes and risers for defects (e.g., cracks). Preferably, an ILI tool should have comparable crack detection capabilities to the AUT systems used during fabrication. However, this is challenging, particularly for small diameter pipes, because all the UT sensors and components need to fit in the small space available. Another requirement is that an inspection causes the least amount of disruption to operations. In other words, a minimally invasive inspection is desirable. This creates the potential for an advantageous trade-off between detection capabilities and ease of deployment. An easy to deploy and minimally invasive inspection tool allows for more regular repeat inspections, e.g. as part of in-service inspection plans (ISIP), thus alleviating the need for the in-service inspection tool to be as high performing (i.e. detect as small flaws) as the external AUT systems that are deployed in a controlled environment during fabrication.

[0014] In different embodiments, both tethered (i.e. deployed via wireline) and free- swimming ILI tool may be used for girth weld crack detection. For example, an internal pipe inspection tool could be fitted with a mechanical UT scanner that scans along a girth weld. This enables UT techniques such as Time of Flight Diffraction (ToFD), Phased Array, and Full Matrix Capture. However, in some embodiments a free-swimming (i.e. untethered) ILI tool for girth weld crack detection that can scan at speeds of up to Im / s may be preferred over a tethered tool.

[0015] In some embodiments, novel ILI tools for girth weld crack detection provide can address subsea production by acquiring valid and reliable inspection data to properly assess the actual condition of critical assets in support of estimating remaining fatigue lives, extending the design life of a system, and providing integrity management through an asset's full life cycle. Furthermore, application of probabilistic fracture mechanics methods could also be used to model the findings from repeat in-service inspections and to support reliability-based inspection planning.

[0016] In some embodiments, the inventive technology may be referred to as Advanced Crack Reflection Ultrasonic Imaging Technology (ACRUIT). The UT transducer array may be constructed in the form of conical phased array UT transducers arranged circumferentially girth weld crack detection using ILI Tools. The conical outer surface of the UT transducer array enables ultrasound scanning along a girth weld by improved targeting of the test area by the ultrasound emitted by the UT transducer array. For example, the angle of the conical outer surface may be selected such that the defects at the test area will have a larger orthogonal projection against the conical surface. Other approaches in selecting the angle of the conical surface to improve sensitivity of the testing, for example improving the strength of the return ultrasound signal through one or more reflections within the walls of the inspected structure that includes the defects. This concept allows to package the inventive sensor arrays as a free-swimming ILI tool, while maintaining or improving the small form factor and industry state-of-the art navigational capabilities. In different embodiments, the UT transducers may be piezoelectric ultrasound transducers, as further explained below with reference to FIG. 5. In one embodiment, the conical array has many elements used for UT beam shaping using Phased Array technology . The small width of the elements allows a high-resolution circumferential scan.

[0017] In one embodiment, a method for defect inspection, the method includes inserting an ultrasound sensor into a solid structure. The ultrasound sensor includes a conical transducer having a plurality of ultrasound transmitters. The method also includes detecting flaws in the solid structure by ultrasound signals emitted by the ultrasound sensor, where an outer surface of the conical transducer is configured to face a segment of the solid structure that is being inspected.

[0018] In one aspect, the method also includes acoustically coupling the ultrasound sensor with the solid structure by an ultrasound couplant configured between the ultrasound sensor and the solid structure.

[0019] In one aspect, the conical transducer is a first conical transducer and the plurality of ultrasound transmitters are a first plurality of the ultrasound transmitters. The method further includes inserting a second conical transducer into the solid structure, the second conical transducer having a second plurality of ultrasound transmitters, wherein an outer surface of the second conical transducer is configured to face the segment of the solid structure that is being inspected.

[0020] In one aspect, the first conical transducer and the second conical transducer have same conical angles.

[0021] In one aspect, the first conical transducer and the second conical transducer have different conical angles.

[0022] In one aspect, the first conical transducer is configured to operate as a transmitter of ultrasound signals and the second conical transducer is configured to operate as a receiver of ultrasound signals. The first conical transducer is configured to face the segment of the solid structure that is being inspected at a first angle and the second conical transducer is configured to face the segment of the solid structure that is being inspected at a second angle. The first angle and the second angle are same.

[0023] In one aspect, the first conical transducer is configured to operate as a transmitter of ultrasound signals and the second conical transducer is configured to operate as a receiver of ultrasound signals. The first conical transducer is configured to face the segment of the solid structure that is being inspected at a first angle and the second conical transducer is configured to face the segment of the solid structure that is being inspected at a second angle; and wherein the first angle and the second angle are different.

[0024] In one aspect, the plurality of ultrasound transmitters are configured proximate to the outer surface of the conical transducer.

[0025] In one aspect, the method also includes transmitting ultrasound signals and receiving ultrasound signals by the plurality of ultrasound transmitters.

[0026] In one aspect, the method also includes receiving the ultrasound signals by a plurality of ultrasound receivers.

[0027] In one aspect, the method also includes operating the plurality of ultrasound transmitters as a phased array ultrasound sensor.

[0028] In one aspect, the solid structure is a riser or a pipe having an internal diameter (ID) within a 4 inch to 8 inch range and a wall thicknesses (WT) up to 2 inch.

[0029] In one embodiment, an inline inspection system for defect inspection includes an ultrasound sensor configured for detecting cracks in a solid structure by ultrasound signals. The ultrasound sensor includes a conical transducer having a plurality of ultrasound transmitters, where an outer conical surface of the conical transducer is oriented to face a segment of the solid structure that is being inspected.

[0030] In one aspect, the system also includes an ultrasound couplant configured between the ultrasound sensor and the solid structure.

[0031] In one aspect, the plurality of ultrasound transmitters are configured proximate to the outer surface of the conical transducer.

[0032] In one aspect, the plurality of ultrasound transmitters are configured for both transmitting and receiving the ultrasound signals.

[0033] In one aspect, the plurality of ultrasound transmitters include a phased array ultrasound sensor.

[0034] In one aspect, the conical transducer is a first conical transducer and the plurality of ultrasound transmitters are a first plurality of the ultrasound transmitters. The system further includes a second conical transducer having a second plurality of ultrasound transmitters, where an outer surface of the second conical transducer is configured to face the segment of the solid structure that is being inspected.

[0035] In one aspect, the first conical transducer and the second conical transducer have same conical angles. In one aspect, the first conical transducer and the second conical transducer have different conical angles.

[0036] In one aspect, the first conical transducer and the second conical transducer have different diameters.

[0037] In one aspect, the solid structure is a riser or a pipe having an internal diameter (ID) within a 4 inch to 8 inch range and a wall thicknesses (WT) up to 2 inch.

[0038] In one aspect, a first diameter and a first length of the first conical transducer and a second diameter and a second length of the second conical transducer are proportional to the wall thickness.

[0039] In one aspect, the first conical transducer is offset from the second conical transducer.

[0040] In one aspect, the first conical transducer and the second conical transducer are mated together.

[0041] In one aspect, the first conical transducer is configured for transmitting ultrasound signals, and the second conical transducer is configured for receiving ultrasound signals.

[0042] In one aspect, the system also includes a third conical transducer having a third pl urali ty of ultrasound transmitters, and a fourth conical transducer having a fourth plurality of ultrasound transmitters.

[0043] DESCRIPTION OF THE DRAWINGS

[0044] The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same become better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, where:

[0045] FIGURE 1 is an image of defects in a solid structure according to prior art;

[0046] FIGURE 2 is a cross-sectional schematics view of defects in a solid structure according to prior art;

[0047] FIGURES 3A and 3B are plan and side views of a sample of inspected structure according to prior art;

[0048] FIGURE 4 shows a sample welded structure according to prior art;

[0049] FIGURE 5 is a schematic view of crack detection in accordance with prior art; FIGURES 6A-6D illustrate conical ultrasound sensors in accordance with embodiments of the present technolog)';

[0050] FIGURES 7-8 illustrate comer trap technique for ultrasound testing in accordance with embodiments of the present technology;

[0051] FIGURE 9 illustrates round trip tandem technique for ultrasound testing in accordance with embodiments of the present technology;

[0052] FIGURE 10 illustrates angle beam technique ultrasound for ultrasound testing in accordance with embodiments of the present technology;

[0053] FIGURE 11 illustrates a time of flight diffraction (TofD) technique for ultrasound testing in accordance with embodiments of the present technology;

[0054] FIGURE 12 illustrates ultrasound path for ultrasound testing in accordance with embodiments of the present technolog)'; and

[0055] FIGURE 13 illustrates A-scan and B-scan obtained in a sample testing in accordance with embodiments of the present technology.

[0056] DETAILED DESCRIPTION

[0057] While illustrative embodiments have been illustrated and described, it will be appreciated that various changes can be made therein without departing from the spirit and scope of the invention.

[0058] FIG. 1 is an image of defects in a solid structure according to prior art. The illustrated solid structure 1 may be a pipe, a raiser, or other metal (e.g., steel) structure. The base material of the structure is denoted with numeral 20, and the weld is denoted with numeral 22. Several defects are illustrated as external defect 24-1 (i.e., external to the weld), embedded defect 24-2 and 24-3, and internal defect 24-4, collectively defects or flaws 24.

[0059] FIG. 2 is a cross-sectional schematics view of defects in a solid structure according to prior art. The illustrated structure 1 is made of base material (e.g., steel) 20 having a thickness 20 and a coating (e.g., polymer) 30. The weld 22 includes one or more defects 24 that should be identified as closely as possible for the structure to have its integrity assessed or to be repaired. An example defect 24 is characterized by its height H and a distance D from the weld root. As explained above, identifying precise location and size of the defect 24 remain a challenge in the industry. FIGS. 3A and 3B are plan and side views, respectively, of a sample of inspected structure according to prior art. The sample structure 1 is shown with the coating 30 removed. The dimensions are shown for illustration only, and in different embodiments the dimension of different elements of the structure 1 may be different. For example, the structure 1 suitable for testing the inventive technology may be characterized by approximately 4" inside diameter (ID) pipe with WT up to 2". In general, smaller IDs represent more challenging scenarios for defect detection, because there is less space available for the ILI tool inside the pipe.

[0060] FIG. 4 is a sample of welded structure according to prior art. The dimensions are shown as examples, and other dimensions are also possible. In many embodiments, the defects are located within the weld 22 or in its vicinity. In practice, an ILI tool requires accurate positioning of the UT sensors inside the pipe with respect to the weld for proper determination of the location and size of the defects 24. However, such accurate positioning of the UT sensors may be difficult with the conventional technologies.

[0061] FIG. 5 is a schematic view of crack detection in accordance with prior art. Some conventional technologies generate ultrasonic waves by a piezoelectric transducer or an electromagnetic acoustic transducer (EMAT) into a solid material 6 (e.g., a metal plate). The piezoelectric transducer includes a vibrating crystal 2 and a couplant 4 (e.g., gel or fluid) that transfers vibrations onto the solid material 6 (e.g., a steel plate). In another conventional technology, the EMAT 15 produces vibrations in the solid material 6. The EMAT 15 includes a permanent magnet 10 coupled with a coil 12. When the alternating current (AC) flows in the coil 12, magnetic field of the permanent magnet 10 interacts with magnetic field created by the AC current in the coil 12 to generate eddy currents in the solid material 6. The energy of these eddy currents are transferred to the crystal lattice of the solid material, producing an ultrasonic wave. When the ultrasonic waves reach a crack 24, a reflected ultrasonic wave is generated. These reflected waves can be detected by a receiver that is also an EMAT. At the receiving EMAT (not shown), the interaction of the reflected ultrasonic waves with the magnetic field of the receiving EMAT induces electrical currents in the receiving EMAT coil circuit. These induced currents can be measured, and further analyzed to characterize the crack 24. Figure 5 schematically illustrates the so- called Lorentz force type EMAT. However, the description generally applies to magnetostriction type of EMATs as well. FIGs. 6A-6D illustrate conical ultrasound sensors in accordance with embodiments of the present technology. In each drawing, the conical ultrasound sensor 1500 includes conical transducers 150, each operating as a phased array transducer having a plurality of ultrasound transmitters (e.g., EMAT transmitters) 15 configured close to the outer surface of the conical transducers 150. In different embodiments, the ultrasound sensor 1500 may include just one or a plurality of the conical transducers 150 that are inserted into a solid structure to be inspected (i. e. , a pipe), where the outer surface of the conical transducer 150 is oriented to face the segment of the structure that is being inspected for defects. In operation, different phases of the ultrasound transmitters 15 can be controlled by a controller 160 (e.g., a digital computer, an analog controller, a digital controller, etc.) such that the conical transducer 150 operates as a phase array. In some embodiments, the ultrasound transmitters 15 can also operate as the ultrasound receivers 15. In other embodiments, the conical ultrasound sensor 1500 may include dedicated ultrasound transmitters 15 and dedicated ultrasound receivers 15.

[0062] In FIG. 6A, the ultrasound transmitters 15 of the conical transducer 150 are carried by a conical housing 17 that is characterized by an angle a. In operation, a preferred direction of an ultrasound ray 19 (i.e., the direction of maximum power of the ultrasound field) is denoted with an angle p, that is, perpendicular to the surface of conical housing 17. Thus, angles a and are related as a + P = 90°. In the embodiment illustrated in FIG. 6A, all the conical transducers 150 have the same angle a, but in different embodiments different conical transducers 150 may have different angles a. For example, FIG. 6B illustrates conical transducers 150 having the angles ai and 0.2. In operation, the transmitting conical transducer characterized 150 by angle ai transmits an ultrasound ray 19 toward the defect 24. Reflected ultrasound ray is received by the receiving conical transducer 150 characterized by angle ai. For certain geometries and locations of the defect 24, a choice of angles ai and a 2 may improve strength of the signal received by receiving conical transducer 150. As explained with respect to FIGS. 7-12 below, the angle a of the conical housing 17 can be selected such that the target area of the inspected structure (e.g., a weld) is exposed to and faces the ultrasound transmitters 15 such that the ultrasound ray 19 reaches the target in shorter time, at an angle that is suitable for detecting the reflected ultrasound ray, where the defects are not obstructed from the ultrasound transmitters 15, etc. FIG. 6C illustrates conical transducers 150 having the angles ai and a2. Furthermore, the conical transducers 150 may be separated by a distance X in operation, and may be characterized by different diameters Di and D2, and different array widths Wi and W2. Distance X diameters Di and D2, and array width (Wl and / or W2) are function of the pipe wall thickness, pipe diameter as well as type of weld to be inspected. In some embodiments, a first diameter and a first length of the first conical transducer and a second diameter and a second length of the second conical transducer are proportional to the wall thickness. For example, the diameter and length of a given conical transducer may be proportionally increased when operating on thicker pipes or risers.

[0063] In operation, the conical transducers 150 may operate as a transmitter / receiver pair, or each may operate in both transmitting and receiving mode. By a proper choice of angles a, diameters D, and distance X, detection for certain geometries and locations of the defect 24 may be improved.

[0064] FIG. 6D illustrates conical transducers 150 having angles ai, 012, as, and 4. Illustrated conical transducers may be characterized by different mutual distances (including mating with each other as illustrated in FIG. 6A), and different diameters D. Again, the illustrated conical ultrasound sensor 1500 exhibits a preferred sensitivity7of the defect detection depending on the angle a, distances X, and diameters D of the conical transducers 150.

[0065] FIGS. 7-8 illustrate comer trap technique for ultrasound testing in accordance with embodiments of the present technology. Such technique may be especially useful for external defects (flaws) 24 that extend to the outer surface (FIG. 7) and internal defects (flaws) 24 that extend to the inner surface (FIG. 8) of the piping or other test specimen. In some embodiments, the reflection amplitude is the strongest, and therefore easier to detect and record, when the beam angle a.2 is approximately 45°. Without being bound to theory, it is believed that the comer trap technique works well for relatively small crack heights, e.g., for the crack heights are 4 mm or less. To improve detection of the defects, the conical transducer 150 is oriented to face the defect 24. The conical transducer 150 may be acoustically coupled with the base material 20 through the couplant 4. For simplicity and clarity of drawings, the couplant 4 is not explicitly shown in the subsequent drawings.

[0066] FIG. 9 illustrates round trip tandem technique for ultrasound testing in accordance with embodiments of the present technology. The comer trap technique may have limited crack height sizing capabilities and sizing crack heights greater than 4 mm may be difficult. This shortcoming may be resolved through the round trip tandem technique, described below. In operation, the round trip tandem technique picks up reflections from the mid part of the pipe wall (e.g., from a defect 24). The figure shows a transmitting conical transducer 150-T placed inside the pipe 20, with a second conical transducer 150-R added to receive the ultrasound reflections from the defect 24, where the ultrasound reflections would otherwise not return to the transmitting conical transducer 150-T. Therefore, angles of the conical transducers 150-T and 150-R are carefully dimensioned to assure proper return of the reflected signal to the receiving conical transducer 150-R. In different embodiments, angles of the conical transducers 150-T and 150-R may be the same or different. Furthermore, the precision of the measurements may be improved by echo dynamics, which makes it possible to improve crack height sizing.

[0067] FIG. 10 illustrates angle beam technique ultrasound path for ultrasound testing in accordance with embodiments of the present technology. The angle beam technique uses an ultrasound beam 19 with an angle that incidents generally perpendicularly on the preparation surface of the weld 22 (see FIG. 4). This approach may result in a strong specular reflection that returns to the conical transducer 150, therefore being particularly suitable for defects that are oriented along the weld preparation surface. Crack height may be determined by measuring the reflection amplitude as a function of axial position of the conical transducer 150.

[0068] FIG. 11 illustrates a time of flight diffraction (TofD) technique for ultrasound testing in accordance with embodiments of the present technology. The TofD techniques relies on a combination of a conical transducer transmitter 150-T that emits the ultrasound and a conical transducer receiver 150-R in accordance with embodiments of the present technology. The so-called lateral wave limits the detection and detectable size of relatively shallow defects 24 that extend toward the pipe surface closest to the conical transducers 150-T and 150-R. For practical in-line inspections of the pipes, this means that ToFD technique has limitations when detecting internal surface (ID) defects 24.

[0069] Without being bound to theory, the inventors have found that different defect detection approaches illustrated in FIGs. 7-11 may be preferred for different types of defects as illustrated in Table 1 below. However, Table 1 should not be understood in an exclusionary way. That is, different measurement techniques may in principle be applicable to any type of defects.

[0070] TABLE 1

[0071] FIG. 12 illustrates ultrasound path 19 for ultrasound testing in accordance with embodiments of the present technology . Such ultrasound path 19 provides an example of a calculated beam direction and shape. In some embodiments, the reflections of the ultrasound path 19 toward the defect 24 (and back to the conical transmitter / receiver 150) can be used to optimize detection of the defects. The root crack flaw appears close to the point where the ultrasound hits the root, which is also at the water-to-steel interface.

[0072] FIG. 13 illustrates A-scan and B-scan obtained in sample testing in accordance with embodiments of the present technology. The upper graph shows a B-scan, and the lower graph shows an A-scan. The B-scan is measured over 90° of a sample fabricated weld defect. The A-scan shown below the B-scan is the measurement that corresponds to the vertical line in the B-scan. The reflection of the lack of fusion defect is clearly visible, around 60 ps in the A-scan measured over 0.5 skip. The noise-like signal between 37 ps and 47 ps are caused by reflections at the water to steel surface. Typically, these reflections have a low amplitude because of the angle of incidence. The above B-scan can be used to measure the length of the defect. In the illustrated case, the result is 20 mm, which is close to the reported truth data of 19 mm. The root crack flaw appears close to the point where the ultrasound hits the root, which is also at the water to steel interface.

[0073] It is to be understood that the presently disclosed and / or claimed inventive concept(s) is not limited in its application to the details of construction and the arrangement of the components or steps or methodologies set forth in the following description. The presently disclosed and / or claimed inventive concept(s) is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

[0074] Unless otherwise defined herein, technical terms used in connection with the presently disclosed and / or claimed inventive concept(s) shall have the meanings that are commonly understood by those of ordinary skill in the art. Further, unless otherwise required by context, singular terms shall include pluralities and plural terms shall include the singular.

[0075] All patents, published patent applications, and non-patent publications mentioned in the specification are indicative of the level of skill of those skilled in the art to which the presently disclosed and / or claimed inventive concept(s) pertains. All patents, published patent applications, and non-patent publications referenced in any portion of this application are herein expressly incorporated by reference in their entirety to the same extent as if each individual patent or publication was specifically and individually indicated to be incorporated by reference.

[0076] All of the articles and / or methods disclosed herein can be made and executed without undue experimentation in light of the present disclosure. While the articles and methods of the presently disclosed and / or claimed inventive concept(s) have been described in terms of preferred embodiments, it will be apparent to those skilled in the art that variations may be applied to the articles and / or methods and in the steps or in the sequence of steps of the method described herein without departing from the concept, spirit, and scope of the presently disclosed and / or claimed inventive concept(s).

[0077] As utilized in accordance with the present disclosure, the following terms, unless otherwise indicated, shall be understood to have the following meanings.

[0078] The use of the word "a" or "an" when used in conjunction with the term "comprising" may mean "one", but it is also consistent with the meaning of "one or more", "at least one", and "one or more than one". The use of the term "or" is used to mean "and / or" unless explicitly indicated to refer to alternatives only if the alternatives are mutually exclusive, although the disclosure supports a definition that refers to only alternatives "and / or". Throughout this application, the term "about" is used to indicate that a value includes the inherent variation of error for the quantifying device, the method being employed to determine the value, or the variation that exists among the study subjects. For example, but not by way of limitation, when the term "about" is utilized, the designation value may vary by plus or minus twelve percent, or eleven percent, or ten percent, or nine percent, or eight percent, or seven percent, or six percent, or five percent, or four percent, or three percent, or two percent, or one percent. The use of the term "at least one" will be understood to include one as well as any quantity more than one, including but not limited to, 2, 3, 4, 5, 10, 15, 20, 30, 40, 50, 100, etc. The term "at least one" may extend up to 100 or 1000 or more, depending on the term to which it is attached; in addition, the quantities of 100 / 1000 are not to be considered limiting, as lower or higher limits may also produce satisfactory results. In addition, the use of the term "at least one of X, Y, and Z" will be understood to include X alone, Y alone, and Z alone, as well as any combination of X, Y, and Z. The use of ordinal number terminology (i.e., "first", "second", "third", "fourth", etc.) is solely for the purpose of differentiating between two or more items and is not meant to imply any sequence or order or importance to one item over another or any order of addition, for example.

[0079] As used herein, the words "comprising" (and any form of comprising, such as "comprise" and "comprises"), "having" (and any form of having, such as "have" and "has"), "including" (and any form of including, such as "includes" and "include") or "containing" (and any form of containing, such as "contains" and "contain") are inclusive or open-ended and do not exclude additional, unrecited elements or method steps. The term "or combinations thereof' as used herein refers to all permutations and combinations of the listed items preceding the term. For example, "A, B, C, or combinations thereof' is intended to include at least one of: A, B, C, AB, AC, BC, or ABC and, if order is important in a particular context, also BA, CA, CB, CBA, BCA, ACB, BAC, or CAB. Continuing with this example, expressly included are combinations that contain repeats of one or more item or term, such as BB, AAA, AB, BBC, AAABCCCC, CBBAAA, CABABB, and so forth. The skilled artisan will understand that typically there is no limit on the number of items or terms in any combination, unless otherwise apparent from the context.

[0080] In the context of this disclosure, the terms "about," "approximately," "generally" and similar mean + / - 5% of the stated value. From the foregoing, it will be appreciated that specific embodiments of the technology have been described herein for purposes of illustration, but that various modifications may be made without deviating from the disclosure. Moreover, while various advantages and features associated with certain embodiments have been described above in the context of those embodiments, other embodiments may also exhibit such advantages and / or features, and not all embodiments need necessarily exhibit such advantages and / or features to fall within the scope of the technology. Accordingly, the disclosure can encompass other embodiments not expressly shown or described herein.

Claims

CLAIMSWhat is claimed is:

1. A method for defect inspection, the method comprising: inserting an ultrasound sensor into a solid structure, the ultrasound sensor comprising a conical transducer having a plurality of ultrasound transmitters; and detecting flaws in the solid structure by ultrasound signals emitted by the ultrasound sensor, wherein an outer surface of the conical transducer is configured to face a segment of the solid structure that is being inspected.

2. The method of claim 1, further comprising acoustically coupling the ultrasound sensor with the solid structure by an ultrasound couplant configured between the ultrasound sensor and the solid structure.

3. The method of claim 1, wherein the conical transducer is a first conical transducer and the plurality of ultrasound transmitters are a first plurality of the ultrasound transmitters, the method further comprising inserting a second conical transducer into the solid structure, the second conical transducer having a second plurality of ultrasound transmitters, wherein an outer surface of the second conical transducer is configured to face the segment of the solid structure that is being inspected.

4. The method of claim 3, wherein the first conical transducer and the second conical transducer have same conical angles.

5. The method of claim 3, wherein the first conical transducer and the second conical transducer have different conical angles.

6. The method of claim 3, wherein the first conical transducer is configured to operate as a transmitter of ultrasound signals and the second conical transducer is configured to operate as a receiver of ultrasound signals; wherein the first conical transducer is configured to face the segment of the solid structure that is being inspected at a first angle and the second conical transducer is configured to face the segment of the solid structure that is being inspected at a second angle; and wherein the first angle and the second angle are same.

7. The method of claim 3, wherein the first conical transducer is configured to operate as a transmitter of ultrasound signals and the second conical transducer is configured to operate as a receiver of ultrasound signals; wherein the first conical transducer is configured to face the segment of the solid structure that is being inspected at a first angle and the second conical transducer is configured to face the segment of the solid structure that is being inspected at a second angle; and wherein the first angle and the second angle are different.

8. The method of claim 1, wherein the plurality of ultrasound transmitters are configured proximate to the outer surface of the conical transducer.

9. The method of claim 1, further comprising transmitting ultrasound signals and receiving ultrasound signals by the plurality of ultrasound transmitters.

10. The method of claim 1 , further comprising receiving the ultrasound signals by a plurality of ultrasound receivers.

11. The method of claim 1, further comprising operating the plurality of ultrasound transmitters as a phased array ultrasound sensor.

12. The method of claim 1 , wherein the solid structure is a riser or a pipe having an internal diameter (ID) within a 4 inch to 8 inch range and a wall thicknesses (WT) up to 2 inch.

13. An inline inspection system for defect inspection, the system comprising: an ultrasound sensor configured for detecting cracks in a solid structure by ultrasound signals, the ultrasound sensor comprising a conical transducer having a plurality of ultrasound transmitters, wherein an outer conical surface of the conical transducer is oriented to face a segment of the solid structure that is being inspected.

14. The system of claim 13, further comprising an ultrasound couplant configured between the ultrasound sensor and the solid structure.

15. The system of claim 13, wherein the plurality of ultrasound transmitters are configured proximate to the outer surface of the conical transducer.

16. The system of claim 13, wherein the plurality of ultrasound transmitters are configured for both transmitting and receiving the ultrasound signals.

17. The system of claim 13, wherein the plurality of ultrasound transmitters comprise a phased array ultrasound sensor.

18. The system of claim 13, wherein the conical transducer is a first conical transducer and the plurality of ultrasound transmitters are a first plurality of the ultrasound transmitters, the system further comprising a second conical transducer having a second plurality of ultrasound transmitters, wherein an outer surface of the second conical transducer is configured to face the segment of the solid structure that is being inspected.

19. The system of claim 18, wherein the first conical transducer and the second conical transducer have same conical angles.

20. The system of claim 18, wherein the first conical transducer and the second conical transducer have different conical angles.

21. The system of claim 18, wherein the first conical transducer and the second conical transducer have different diameters.

22. The system of claim 18, wherein the solid structure is a riser or a pipe having an internal diameter (ID) within a 4 inch to 8 inch range and a wall thicknesses (WT) up to 2 inch.

23. The system of claim 18, wherein a first diameter and a first length of the first conical transducer and a second diameter and a second length of the second conical transducer are proportional to the wall thickness.

24. The system of claim 18, wherein the first conical transducer is offset from the second conical transducer.

25. The system of claim 18, wherein the first conical transducer and the second conical transducer are mated together.

26. The system of claim 18, wherein the first conical transducer is configured for transmitting ultrasound signals, and wherein the second conical transducer is configured for receiving ultrasound signals.

27. The system of claim 18, further comprising a third conical transducer having a third plurality of ultrasound transmitters, and a fourth conical transducer having a fourth plurality of ultrasound transmitters.

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