Improving hard spot detection, characterisation and prioritisation

Pipeline hard spots: created due to localised quenching of steel during the manufacturing process. A potential threat to pipeline integrity, hard spots can become brittle and crack with time and under certain conditions. As such, operators with an environment conducive to the development of these cracks are very interested in detecting and addressing the threat before they contribute to a failure event.

A major US pipeline operator recently suspected hard spots with potential for cracking on a section of one of its 30 in. pipelines. The operator needed the ability to not only locate the hard spots, but to detect cracking initiated within the hard spots themselves. This level of characterisation would provide the operator with a means to prioritise, allowing the operator to address the most critical hard spots first.

As part of the commitment to safe and reliable operation, the operator requested support from global pipeline solutions provider T.D. Williamson (TDW) – to provide improved detection and characterisation of its hard spot integrity threats. The technology selected was the Multiple Dataset Platform (MDS) with SpirALL® Magnetic Flux Leakage (SMFL). MDS utilises multiple technologies, on the same tool, to overcome the limitations of individual inspection technologies. The platform includes Deformation, High Field Axial Magnetic Flux Leakage (MFL), Patented SpirALL® MFL, Low Field Axial MFL, and XYZ Mapping.

Each technology on the platform provides a unique assessment of an integrity threat. In this case, the Low-Field MFL provides primary detection of hard spots, High Field MFL confirms, and SpirALL® MFL identifies any crack-like defects within the hard spots. In addition, the data collected by the MDS platform is captured, synchronised, and analysed in a single software, providing a unique comprehensive assessment where one, two, or even three technologies may not be sufficient to detect, characterise, size, and prioritise given integrity threats.

The MDS inspection analysis confirmed the operator’s suspicion: cracking within hard spots. Due to the advanced characterisation offered through the overlapping inspection data, the operator was able to prioritise the hard spots and address as needed.

The MDS platform, engineered by TDW, has been used to detect integrity threats such as hook cracks, lack-of-fusion, selective seam weld corrosion, mechanical damage, and axially-extended metal loss. As a result of this innovative technology, pipeline operators are looking to the potential of MDS to help solve detection and characterisation challenges with a variety of additional integrity threats.

Adapted from press release by Hannah Priestley-Eaton

Read the article online at: https://www.worldpipelines.com/business-news/05092014/improving-hard-spot-detection-characterisation-and-prioritisation/