Pig and dig for your integrity program: Are you sure you are doing enough? The argument for having a second set of eyes analyze your ILI data.

 

Introduction


shutterstock_144108217So, what keeps you up at night? If you have pipelines to operate or manage, then you probably have an in-line inspection (ILI) program. The process most operators follow for their ILI program is to run the tool, get the results from the vendor and then respond to the features called out on the Excel spreadsheet. This common process generally gives good results, and the program is even more robust if the operator has defined specific response criteria for the ILI vendor to use.

But how many operators take the time to look at details in the data using the vendor-supplied software? If you have been sleeping well, you might be surprised to find that your inspection data may be trying to tell you something – but only if you take the time to look!

 

ARE YOU DOING ENOUGH?

Even with the best intentions it is difficult to define a response criteria that includes all scenarios and interaction criteria. Most operators say they have done a pretty good job and trust the tool vendors analyst to identify and classify all actionable anomalies. While this would be the perfect scenario, it is not the one that usually plays out. It may be ideal to think that the response criteria are “pretty good” and that the ILI analyst is very good, but it is probably a mistake to bet the safety and integrity of your pipeline system on that assumption.

It’s prudent to develop an expectation that you have a second set of eyes review the detailed data, looking to confirm that there are no features or “signals” in the data that warrant additional investigation. This can be done in-house, or you can use an outside firm to facilitate this “enhanced ILI” review. It takes a trained eye, so a level 2 certified analyst or above should perform the analysis.

What should they look for? An analyst’s trained eye would look for unusual features, signals or interactions. Some areas of interest are:

  • Areas of speed excursion/signal degradation
  • Pipe in cased crossings
  • Small pipe joints or mitered bends
  • Dents that interact with either the long seam or a girth weld
  • Long areas of general corrosion
  • Corrosion around a girth weld (due to shrink sleeves or poor field applied coating). This can run longitudinally or it can actually run circumferentially.
  • Unusual metal loss features
  • Corrosion in or across a long seam or girth weld
  • Specific “signatures” like MIC or AC-induced corrosion
  • Indications of selective seam corrosion

The analyst can refine the data analysis if you have tool performance data, based on digs or, even better, a unity plot. While the tool performance data is helpful, it is not required to complete a beneficial review of the ILI data by the second set of eyes.

 

ANOTHER BENEFIT OF a second set of eyes

A second benefit of having an analyst look at the detailed data is to compare the visible features within the ILI data to the data provided by GIS. This comparison allows a true-up of the GIS system with the ability to add (or subtract) information to match the ILI data. Some of the items that can be found include:

  • Casings
  • Valves, fittings
  • Mitered bends
  • Small pipe pups
  • Discrepancy in expected wall thickness

While the GIS systems are improving every day, it is helpful to have a true-up process built in to validate and correct the information with data from the ILI vendor.

 

Conclusion: Check With an Expert

Managing the integrity of a pipeline is not really about what you found and responded to using ILI results. The true integrity of the pipe is based on how confident you were about the features that remain in the pipe that you decided not to respond to.

To gain confidence that you have done your due diligence, you must have a process in place that requires a second trained person to review the detailed data the vendor provides. The ILI tool provides you with a wealth of information, but you have to be willing to look.

 G2 Integrated Solutions can help you develop an enhanced ILI review, or our trained analysts can perform it for you. 

If you want to ask an expert a question about your pipeline integrity program today, please contact us.

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