Case Studies

Putting theory into practice

A special configuration of ultrasonic ILI tools with optimized sensor carrier design for the highest accuracy crack and corrosion inspection respectively.

The Challenge

A 40" pipeline over 400 km (250 miles), that is integral to its operator’s services, required in-depth inline inspections (ILI). As part of the operator’s ongoing integrity management program, it conducts cyclical crack and corrosion inspections. Due to an existing relationship and trust in its data accuracy, the customer utilized NDT Global’s new highest resolution ultrasonic crack and metal loss inspections services. This pipeline operates at high capacity and has minimum throughput requirements to meet, even during inspection, which presented a challenge for an ILI.

In order to protect the environment, the operator must explore and leverage advances in technology to provide better quality pipeline integrity information. NDT Global completed tests to evaluate if doubling the axial and circumferential resolution would lead to more reliable corrosion and crack feature identifications respectively. The operator delivered a spool of pipe to the testing yard at NDT Global where pull tests were performed at these higher-resolutions. The test pipe included a range of small pitting corrosions with diameters in the lower range of the tool performance specifications.

NDT Global demonstrated the Evo Series UMp 1.0 inspection tool’s capability to detect and size challenging small pitting corrosions, down to 5 mm (0.2 in) in diameter. Also, to combat the threat posed by cracks or crack-like anomalies, NDT Global illustrated the sizing capabilities and specifications of its ultrasonic crack inspection tool with highest resolution. Pipeline integrity must be safeguarded while transporting crude oil at almost maximum throughput. Normal transmission speed is approximately 2 m/s (4.47 mph). During short windows of scheduled maintenance, speed can be reduced, but no lower than 0.9 m/s (2 mph). This is not an issue with older technologies or even standard ultrasonic technology (UT) but it is a challenge for the extremely high resolutions that the operator was seeking.

The Solution

To ensure the operator’s exacting resolution requirements were achieved, NDT Global separately utilized its UT crack and corrosion tools that both deliver the highest resolution measurements available. Both tools deployed special configurations with optimized sensor carrier designs to deliver higher accuracy. NDT Global conducted in-house testing to determine which technology would be the best application for this test run.

The higher resolution crack inspection tools have an increased number of sensors, which present greater and more accurate data for analysis. Given its length and the integral role this pipeline plays in the operator’s program, the increased redundancy in sensors provides added assurance of first run success and highest data quality, offering the operator greater insights into the status of its key asset.

For this operator, the challenge was not just to achieve the industry’s leading resolution, it was to conduct the highest possible resolution run at a speed greater than 0.9 m/s (2 mph). A further requirement was to complete the inspection during a scheduled maintenance window when the flow rate would be reduced for a short period of time.

By working closely with the pipeline operator and completing successful tool enhancement test runs, the NDT Global project team showed the flexibility and project management skills required to complete these inspections during the available window.

The Results

  • No trade-off between resolution and speed. The operator wanted to achieve the highest-resolution crack and corrosion inspections available today without having to reduce its transmission speed. This was achieved with an actual tool speed of between 1.1 m/s and 1.2 m/s (2.46 and 2.68 mph).
  • A new solution successfully delivered. Normal transmission speed is over 2 m/s (4.47 mph) and there was just one window available where transmission speed would be reduced with enough time to complete the run. NDT Global worked with the operator to create a functional project plan. This plan depended on the availability of new customized tools. This positive result was achieved due to a) the quality of internal testing by NDT Global as part of its new product development and b) the company’s determination to keep its commitment to the operator.
  • Lowering long term operational costs with future proof data. Collecting this high-resolution data ensures future run comparisons will deliver the required integrity information. In 5, 10 or 15 years’ time, following a future inspection, they will need to know if a feature already existed and how it changed. If only lower-resolution data was collected, future feature comparisons may be inconclusive.
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