Extraction of RBP from filtered Wall Thickness (WT) inspection data (illustration: NDT Global)

When conducting ongoing pipeline integrity management programs, it is vital for operators to have access to as much information regarding potential corrosive activity on their pipeline as possible. The data provided from river-bottom profiles (RBP) offers a more in-depth look at anomalies in a pipeline that occurred because of corrosion.

An ultrasonic inline inspection (ILI) reliably detects and sizes corrosion anomalies in pipelines. The recorded ultrasonic technology (UT) inspection data provides a solid basis for a RBP, as this data directly extracts into a RBP. RBPs, i.e. the plot of remaining wall thickness versus distance, provides a detailed description of the actual shape of a corrosion anomaly (see image), at an axial resolution down to 0.75 mm. In contrast, magnetic flux leakage (MFL) data does not typically offer such detailed data, nor the same data accuracy.

Following an inspection run, NDT Global’s experienced data analysis team analyzes the recorded inspection data to detect, classify and size anomalies. For metal loss anomalies, this sizing procedure determines:

• The peak depth of the anomaly present.
• Minimum remaining wall thickness.
• Total length of the anomaly.

Corrosion that goes unchecked leads to potentially calamitous impacts on an operator's integrity management program, which underlines the integral role that accurate data – such as the data provided by high-resolution ultrasonic ILI tools – plays in a proactive pipeline management program. The proliferation of RBP comparisons increases the accessibility of accurate data regarding the presence and location of corrosion. Knowing the presence of corrosion in their pipelines, as well as the growth rate of such defects, enables pipeline operators to proactively and intelligently plan their maintenance, operate their pipelines and manage costs, all of which greatly aid long-term planning and safety.

Tags: NDT Global