Seam Weld Assessment

Context is key in Seam Weld Assessment

Seam weld assessment is challenging and consequential for pipeline operators.

Seam weld assessments can be one of the most challenging factors in pipeline inspection. Imperfections within welds, repair work, and even tape wrap coatings can lead to misleading data from many inline inspection tools, leaving you open to missing critical associated metal loss. Assessments are confounded further by a lack of standard terminology across the industry. Depending on the technology used, “coincidental” metal loss in one inspection could be deemed “preferential” in another. While the industry works to better quantify these terms, you need clear information for actionable decisions.

The most effective seam weld analysis combines the right technology to capture ample data along with expert analysis to interpret it. With both factors working together, you get a more accurate picture of any metal loss to avoid unnecessary digs and shutdowns, while remaining confident you’re not missing any potential issues.

The industry has not yet settled on clear criteria for defining metal loss and deformities close to the seam. Today, these anomalies are classified as follows:

Coincidental: Pre-existing metal loss patterns that coexist with the placement of the long seam

Example of pre-existing metal loss patterns that coexist with the placement of the long seam.

Adjacent: Metal loss patterns that align near the seam, but do not cross it

Preferential: Metal loss patterns interacting within the seam due to physical characteristics of the seam

Example of metal loss patterns interacting within the seam.

Seam health is critical

As you’re aware, a pipeline offers 360 degrees of area for potential damage, both internally and externally. Complex corrosion, pinholes, and pits-in-pits can strike anywhere and cause operational problems. Thankfully, seam failures are not common, but when they happen, they are often significant. An inline inspection that does not capture key data about the seam may not be delivering full value for your operation.

Other axial MFL inline inspection technologies do an adequate job detecting the more obvious seams in Flash Welded and DSAW pipes. However, with the manufacturing process of ERW pipes it tends to result in seams flush to the body wall thickness, making it harder to detect with standard MFL tools and in some instances with the naked eye, when on site of an excavation. With seam detection limitation in ERW pipes, this essentially creates blind spots in the data. With Entegra UHR tools not only is the ERW seam detectable in the primary MFL sensors, but is also detected on a regular basis by both the internal sensors (ID/OD) and caliper sensors. 

In contrast, Ultra-High Resolution (UHR) ILI from ENTEGRA utilizes many more sensors, picking up on even fine ERW seams and detecting on-seam metal loss as small as 3mm in size.

The design of ENTEGRA’s Ultra-High Resolution ILI tool.
Inspections using other MFL tools fail to consistently detect and identify the long seam, delivering an incomplete analysis. UHR MFL tools from ENTEGRA have 2X the sensors and a much higher sampling frequency versus other MFL tools, for a more thorough and detailed view of the seam.

The value in data interpretation

Capturing comprehensive data from the seam is vital, but only an accurate interpretation makes that data useful. Automated data analysis methods, primarily using software and algorithms, can mistake harmless anomalies as potentially injurious, resulting in unnecessary shutdowns, digs and/or repairs.

ENTEGRA uses experienced, highly trained, human data analysts to make sense of seam weld assessment data gathered by our tools. We review not only the data captured by our ILI process, but your own records of repairs and past issues to provide a holistic picture of any threats facing your pipeline seam. This approach enables us to put the data into the proper context, so you can make informed decisions about your operations.

An excellent example is the case illustrated here, where inspection data indicated a possible issue along the seam of a 30” SSAW pipe. Automated data would often flag this kind of anomaly as potentially injurious, simply because of the amount of activity happening over the seam. Data analysts at ENTEGRA, however, interpreted the nuances in this data to determine the anomaly was not injurious, but the result of the reinforcement backing layer deteriorating on the interior diameter of the pipe. This in-depth analysis, only possible with experienced analysts, allowed the operator to avoid an unnecessary dig.

ENTEGRA Data Image of Long Seam data from MFL, Internal, and Caliper sensors, compared to a photo of the seam on the pipe.
UHR MFL sensors picked up an anomaly in this pipe that would commonly be flagged as potentially injurious in automated data analysis programs. Experienced data analysts at ENTEGRA determined the sensors were picking up a backing layer that posed no threat to the seam, so no repair was needed.

In another case, ENTEGRA analysts were able to distinguish preferential metal loss in fine detail, raising an important red flag for the operator. In contrast, the second image below would likely be interpreted by automatic data analysis as a threat to the seam strictly based on its placement. However, experienced analysts at ENTEGRA spotted a pattern that matched the exterior tape wrapping on the pipe, revealing coincidental loss that called for putting this pipe on the operator’s watchlist, but no need for immediate action.

ENTEGRA data of preferential versus coincidental metal loss along the seam.
In the top image, the sensitivity of UHR MFL from ENTEGRA picked up small but critical metal loss along a seam. In the bottom image, data analysts were able to interpret this metal loss as coincidental, recognizing the metal loss pattern indicated the anomaly groups’ origin was not inherent to the seam itself.

Gather more data, interpret it more effectively

Ensuring the integrity of pipeline seams requires gathering an abundance of data and analyzing it with real-world understanding that every pipeline has an array of variables to consider. ENTEGRA brings together both, with sophisticated UHR ILI tools that gather detailed data and highly trained analysts who can put that data into context, protecting your seams and your operations.