By utilizing complementary combined technologies, data sets for corrosion, deformation, geometry, pipe grade, cracking and interacting features can be combined during analysis – increasing the probability of the identifying, detecting and sizing capabilities.
A 24”, 50-kilometer-long natural gas distribution pipeline in Canada required an inline inspection (ILI). The operator had primary concerns about stress corrosion cracking (SCC), internal and external corrosion, deformation, and hard spots. Additionally, record verification was not possible because the line had recently changed ownership, raising concern about cleanliness and geometric deformations.
Given the multitude of potential anomalies and unknown cleanliness, a combined solution was determined to be most suitable. The custom solution consisted of a progressive cleaning campaign followed by ILI technologies for the detection of corrosion, cracking and geometric anomalies.
The progressive cleaning campaign involved numerous single- and multi-body cleaning tools, including a heavy-duty cleaning tool complete with a magnetizer typically found on magnetic flux leakage (MFL) technology. Additionally, a pipeline data logger was utilized to collect critical operational data, which helped to gauge the effectiveness of the cleaning program. The initial cleaning runs produced approximately 200 liters of debris per run. More than twenty cleaning runs were performed in total, until the amount of debris was reduced to a level suitable for an ILI. The pipeline’s cleanliness was confirmed with a high-resolution caliper ILI tool equipped with both mechanical deflection measurement technology and hall sensor lift-off measurement capability – ideal for the measurement of geometry defects and debris deposits in the pipeline.
Once the progressive cleaning campaign had been concluded and the geometry confirmed suitable for an ILI, a combination tool equipped with high-resolution axial MFL detection, pipe grade sensing technology and dual magnetization was run through the line in order to:
- Assess general circumferentially-orientated corrosion
- Determine the pipe grade of each joint
- Detect hard spots
Additionally, a circumferential MFL tool was run immediately after the combination tool in order to:
- Augment the axial MFL tool’s assessment of general corrosion
- Provide an assessment of any axially-orientated corrosion
- Augment the data collected by the following EMAT inspection
Finally, to complete the ILI, a high-resolution EMAT crack detection inspection was performed in order to:
- Determine areas with coating disbondment
- Detect and accurately size crack anomalies
- Conclude and assess the presence of SCC, with support of the Crack Management Framework
Through this successful project, the operator received the information necessary to complete missing records, fulfill regulatory requirements, and ensure safe and reliable operation of the pipeline. Additional benefits of the combined solution include:
Robust Data Collection: Thanks to the complementary combined technologies, the data sets for corrosion, deformation, geometry, pipe grade, cracking and interacting features could be combined during analysis – increasing the probability of identifying, detecting and sizing capabilities.
Efficient Integrity Management: The combined solution provided the operator with complete and concise information on the integrity of the pipeline, resulting in reduced uncertainty and minimized disruptions for activities such as validation digs. Ultimately, the operator was able to ensure optimal throughput while saving valuable time and avoiding unnecessary costs.