Advanced NDT Techniques to Incorporate in Oil & Gas Industry

Advanced NDT Techniques to Incorporate in Oil & Gas Industry

First of all the most important reason to go for advanced techniques is the ease of inspection, reliability of data in real-time, and maintaining asset integrity backed upon high-quality data and corrosion mapping to eliminate unpredictable variables in the equipment. When it comes to inspection in petrochemical industries there are various methods.

All of the methods have a few advantages over one another but we have to select a method best suited for our application. The  various advanced NDT methods used are; 

PAUT

PAUT can be visualized as Ultrasonic testing with a multitude of probes. The advantage of using PAUT is that we can achieve real-time wave manipulation like changing the incident angle and focal length hence the rays can be swept across the material thereby covering the object. Due to this, it is the most widely used advanced NDT method for flaw detection and corrosion mapping.

Automated UT

AUT is a technique generally used in piping and pipeline inspection. In this technique, a metal brace is placed on the outer periphery of the pipe and a bug (housing of transducers and receivers) is allowed to move on the brace and the results can be accessed on a screen or software. The main advantage of AUT over manual UT is just that time of the inspection is reduced and repeated inspection is easy and hence the process can be optimized for better results.

TOFD

TOFD is a type of NDT inspection which is most reliable in the pre-service inspection of welds and for accurate assessment of joints for safety and integrity of assets but TOFD alone is not recommended as it has limitation regarding the coverage of the surface. Hence TOFD is generally recommended with PAUT for best inspection.

LRUT

LRUT is generally used to check for corrosion, erosion, pitting in the pipes. The biggest advantage of this method is that meters of pipes can be tested form a single location. In LRUT sound is transmitted along the length of the pipes and returning echoes indicated corrosion, erosion, pitting, etc.

AET

AET is an NDT method where a load I applied to the object to be tested. Sensors are placed on the surface of the object, if there are any defects or discontinuities the generated stress waves in the material and our sensors pick it up, these signals can be interpreted for sizing and defect identification.

ART

ART is a testing process in which acoustic sound is emitted in the material as the velocity of sound in the material is known the resonance condition is found out for the defect and identification is done.

MFL

MFL inspection method uses permanent magnets or electromagnets to magnetize the part up to the saturation point and changes in the magnetic field are recorded. If there are any discontinuities the magnetic field leaks and then this leakage is analyzed to determine the location and nature of the defect both near the surface and far away.  

A Combination of PAUT and TOFD instead of manual NDT for shell and roof plates for storage tanks, if the company is cost constraints than only PAUT can also be an option. While for bottom plates we can recommend you to use MFL as it is possible to be applied over coating up to 6mm thick.

If you read carefully the API 650 it makes a precise differentiation between LFET and MFL, recognizing the MFL like the right technology to inspect Bottom Tanks.

ANDT is committed to providing Total Quality Assurance and ensuring inspections meet deadlines, standards, and are carried out safely and efficiently. While the schedule of maintenance is coordinated in such a way that minimum disruption in business occurs while providing an optimum level of inspection within minimum possible time.