The Most Innovative NDT Techniques in Oil and Gas

Innovations in NDT technologies are helping oil and gas producers in all production phases— upstream, midstream, and downstream—more efficiently inspect critical assets with a greater probability of detecting volumetric flaws and defects. Whether planning additional infrastructure to handle new reserves, repairing corroding piping and storage, or inspecting existing infrastructure, the latest innovative NDT techniques in oil and gas deliver improved inspection accuracy and efficiency. Three of the most effective techniques focus on long seam welds, pipe corrosion, and hydrogen-induced cracking.

Long Seam Weld Inspections

The oil and gas industry is transitioning from radiographic weld inspections to ultrasound (UT) inspections. Radiographic testing (RT), when done correctly, provides high-quality images. However, utilizing RT tools and techniques also brings a host of challenges to the table.

• Equipment setup and inspection may interfere with works in progress or other on-site activities.
• Typically requires access to both inside and outside of the welded joint.
• Qualified personnel are required to correctly interpret radiographic images.
• There are inherent health hazards in X-ray and gamma radiation.

Innovative NDT ultrasound techniques that combine phased array (PA) and time-of-flight-diffraction (TOFD) are better suited to the cylindrical geometry of long seam weld inspections. In comparison to RT, UT instruments facilitate faster setup, reduce inspection time, have none of the health risks associated with radiation, and ensure the full volume of a weld is covered.  

To further improve the efficiency and accuracy of long seam weld inspections, PA and TOFD techniques are simultaneously applied with the aid of a crawler controlling the inspection process. The two-sided phased array configuration probes for surface-breaking and planar flaws. The TOFD technique identifies embedded flaws and provides accurate through-wall sizing performance. Rugged construction and low-profile component design facilitate inspections in harsh conditions and low-clearance environments. Modular construction allows quick configuration changes for axial and circumferential inspections.  

With constrained resources and budgets, producers are challenged to keep up with weld inspection demands, pre-service or in-service. Ease of setup and configuration, inspection speed enabled by mechanical controls, and greater accuracy of combined PA and TOFD techniques enable providers to manage long-seam weld inspections with greater efficiency.

Dissimilar Metal Weld Inspections: Different metallurgical properties, grain alignments, acoustic characteristics, geometries, bring an added challenge accurately detecting flaws in DM welds. Flaws can be hard to detect. Learn how the latest innovations in portable phased array techniques enable technicians to perform DM weld inspections with greater efficiency and probability of detection.

Corrosion Detection

The cost of corrosion in the US oil and gas industry was estimated by NACE international to be well over $1.3 billion. An entire industry segment is dedicated to corrosion prevention and remediation methods. With vast and complex oil and gas infrastructures, however, corrosion is inevitable. Accurate detection and diagnosis are critical in determining the appropriate methods to mitigate or eliminate the problem and its potential consequences.  

Innovation in UT phased array technologies—scanners, software, and visualization—greatly improve the probability of detection and image details. Two-axis scanners and real-time visualization of the process ensure the entire area of interest is covered. Improved signal-to-noise ratio (SNR) provides better lateral resolution relative to surface scan speed.

Software and advanced analytic algorithms incorporated in hand-held instruments further enhance the efficiency and accuracy of inspections. Streamlined setup of focal laws for 2D matrix arrays and definitions of 2D matrix probes, wedges, beam steering, beam skewing, and focusing depth reduce inspection time. Displays show the area being mapped and detailed statistical information associated with the map, while areas of interest can be automatically isolated and analyzed. Inspection reports include detailed 3D color images to illustrate the extent of the corrosion and condition of assets.

Portability, positional accuracy, and powerful performance for detailed data analysis and visualization give inspectors confidence that corrosion mapping inspections are completed thoroughly.

High-Temperature Hydrogen Attack  (HTHA) Detection

UT Phased Array technologies are also useful for detecting damage caused by hydrogen diffusion in metals like steel, titanium, and vanadium. High temperatures associated with refining processes increase the likelihood of hydrogen embrittlement or high-temperature hydrogen attack. These reduce the tensile strength and ductility of metals and ultimately result in hydrogen-induced cracking (HIC).

Because of their small size in the early stages of HTHA, voids can be difficult to detect. However, a range of innovative NDT techniques using ultrasound technology can now be used to proactively detect hydrogen-induced cracking and avoid serious consequences.

• TOFD for initial screening of base material and welded regions. Increased grain noise and clustering in A-Scan signals indicate early-stage HTHA.

• TOFD Ultra Low Angle (TULA) for initial screening of thicker base material. Increased back-scattering and clustering in A-Scan signals indicate HTHA.

• Standard PA UT for secondary inspection. Selected focusing, using 32 or 64 active elements, detects clusters of voids and micro-fissures.

• Total Focusing Method (TFM) for secondary inspection. Defect confirmation uses strong “total focusing” capability.

The latest UT instruments work with a wide range of application-specific probes to support these recommended inspection techniques and ensure efficient detection and accurate characterization of HTHA damage.

NDT Techniques for Oil and Gas: Innovations in Efficiency and Accuracy

Long-seam welds, corrosion, and HTHA inspections are performed more efficiently and with greater accuracy as a result of innovative NDT techniques in oil and gas using UT technologies. Portable instruments facilitate rapid setup. Application-specific scanners provide greater resolution. Powerful analytic algorithms increase the probability of detection. Real-time 3D maps display detailed characteristics of volumetric flaws and defects. Oil and gas producers challenged with a backlog of inspection requirements are wise to investigate the latest NDT techniques that enable lean and efficient inspection processes.

Zetec is a global leader in nondestructive testing (NDT) solutions for the critical inspection needs of the oil and gas industry. We are a single source for high-performance solutions in both eddy current and ultrasonic technologies that help clients ensure asset integrity. Contact us today to learn how Zetec delivers innovative solutions that enable efficient and accurate inspections.