Case Study: Characterizing Puddle Welds Across 70 Miles of Pipeline

Puddle welds (metal deposition) used to be a common form of pipeline repair in the United States so that, today, it’s not unusual to encounter lines with tens of thousands of these anomalies — each one posing a nuisance to pipeline operators. Since puddle welds are made using a deposition of metal, standard MFL ILI inspection has difficulty distinguishing them. In automated analyses, the shoulder of a puddle weld generates a “dip” in the magnetic flux, leaving puddle welds classified as corrosion which can lead to unnecessary repair digs. Or, quite often, the opposite can happen: Puddle welds may mask injurious metal loss, leaving potential problem areas undetected.

With a higher number and density of sensors, ENTEGRA^® Ultra-High Resolution ILI technology more accurately characterizes puddle welds and other interacting corrosion. Combined with the expertise of our skilled data analysis team, ENTEGRA is able to properly classify puddle welds and reduce headaches for pipeline operators.

For one pipeline operator in Texas, the results of our analysis eliminated missed calls and unnecessary digs, ultimately delivering superior value and peace of mind for the customer. Here’s how it worked.

Capturing more data in a single ILI run

In this case, the customer requested an inspection of 70 miles of a liquid line, made up of lap-welded pipe. A previous ILI run had proved less than informative. The analysis from this initial vendor was unable to distinguish between thousands of puddle welds and areas of significant metal loss.

ENTEGRA conducted a new ILI utilizing our 8” MFL/CAL/IMU combo tool. In a single run, conducted over the course of two days, the ENTEGRA team was able to gather all necessary data to begin analysis of the full length of the line.

Thorough analysis, expert interpretation

The analysis process at ENTEGRA uses both robust automated analytic tools and detailed data interpretation conducted by our team of highly trained Level 3 analysts. We use both types of analysis because there are many anomalies that simply can’t be fully understood with automated algorithms. The process of characterizing a large number of puddle welds can be long and painstaking, but it’s necessary to provide the most actionable information to the operator.

As the analysis process continued, ENTEGRA provided weekly reports to the customer with QA, allowing for ongoing pipeline remediation. This way, the customer did not need to wait for a final report in order to begin protecting their operations.

Actionable findings

The complete analysis revealed a complex combination of repairs and anomalies that could not have been understood without the right combination of technology and expert interpretation. Across this 70-mile pipeline, ENTEGRA detected, identified and characterized more than:

• 4,500 dents
• 441,000 metal loss anomalies
• 36,500 puddle welds

With an accurate understanding of the various repairs, anomalies and metal losses in the line, the operator could prioritize areas of focus and remediation, and reduce worries about unexpected downtime. Through dozens of miles of pipe, the ENTEGRA team went the distance to help this operator run with more efficiency and confidence.