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Advanced NDT Techniques to Incorporate in Oil & Gas Industry

Advanced NDT Techniques to Incorporate in Oil & Gas Industry

The primary reason to choose advanced techniques is the ease of inspection, the reliability of real-time data, and the ability to maintain asset integrity through high-quality data and corrosion mapping, which helps eliminate unpredictable variables in equipment. In the petrochemical industry, multiple inspection methods are available.

Each method has its own advantages, and the best approach must be selected based on the specific application. Some of the advanced NDT methods commonly used include:

PAUT

Phased Array Ultrasonic Testing (PAUT) can be seen as an enhanced form of Ultrasonic Testing that utilizes multiple probes. The key advantage of PAUT is its ability to manipulate the ultrasonic waves in real-time, such as adjusting the incident angle and focal length. This allows the sound waves to be directed across the material, ensuring comprehensive coverage of the object. Due to this flexibility, PAUT is one of the most widely used advanced NDT methods for detecting flaws and performing corrosion mapping.

Automated UT

Automated Ultrasonic Testing (AUT) is commonly used for inspecting pipingand pipelines. In this technique, a metal brace is placed around the outer circumference of the pipe, and a "bug" (housing the transducers and receivers) moves along the brace while performing the inspection. The results are displayed on a screen or software for analysis.

The main advantage of AUT over manual UT is the reduction in inspection time. It also allows for easy repetition of inspections, making the process more efficient and optimized for better results.

TOFD

Time of Flight Diffraction (TOFD) is a highly reliable NDT method, particularly for pre-service inspection of welds and for accurately assessing the safety and integrity of joints. However, TOFD alone has limitations in terms of surface coverage. For optimal inspection results, it is generally recommended to use TOFD in conjunction with PhasedArray Ultrasonic Testing (PAUT).

LRUT

Long Range Ultrasonic Testing (LRUT) is primarily used to detect corrosion, erosion, and pitting in pipes. The main advantage of this method is its ability to test several meters of pipe from a single location. In LRUT, sound waves are transmitted along the length of the pipe, and returning echoes help identify issues like corrosion, erosion, or pitting.

AET

Acoustic Emission Testing (AET) is an NDT method in which a load is applied to the object being tested. Sensors are placed on the surface of the object, and if there are any defects or discontinuities, stress waves are generated within the material. These waves are detected by the sensors, and the signals are analyzed to identify and size the defects.

ART

Acoustic Resonance Testing (ART) is a testing method in which acoustic sound waves are emitted into the material. Since the velocity of sound in the material is known, the resonance condition can be determined for the defect. This helps in identifying and assessing the defect.

MFL

Magnetic Flux Leakage (MFL) is an inspection method that uses permanent magnets or electromagnets to magnetize the part up to its saturation point. Any changes in the magnetic field are recorded. If there are discontinuities, the magnetic field leaks, and this leakage is analyzed to determine the location and nature of the defect, both near the surface and deeper within the material.

A combination of Phased Array Ultrasonic Testing (PAUT) and Time of Flight Diffraction (TOFD) is recommended over manual NDT for inspecting shell and roof plates of storage tanks. If the company faces cost constraints, PAUT alone can also be an option. For bottom plates, MFL is recommended, as it can be applied over coatings up to 6mm thick.

Upon reviewing API 650, it is clear that the standard differentiates between Low Frequency Eddy Current Testing (LFET) and MFL, recognizing MFL as the preferred technology for inspecting tank bottoms.

ANDT is dedicated to providing Total Quality Assurance by ensuring inspections meet deadlines, adhere to standards, and are conducted safely and efficiently. Maintenance schedules are coordinated to minimize disruption to business operations while providing the highest level of inspection within the shortest possible time.