Many pipelines are vulnerable to multiple threats and damage types such as internal and/or external corrosion, axial and/or circumferential cracking, laminations, gouging, dents, ovalities and wrinkles. These different types of damage may occur in isolation or can occur coincidental at the same location in the pipeline. Whilst two or more of these feature types may be coincident in the pipeline, the different feature types often require detection by different ILI technologies which are quite often run at different times and even by different ILI vendors.
It is important to identify where different types of features are coincident:
• Discrimination and sizing of certain feature types can be adversely affected and hence uncertainties may be higher at these locations.
• Evaluation of feature severity should account for the types of feature present and any interaction between features.
• To aid the excavation and repair planning processes.
It can be difficult and time consuming to identify the exact location where multiple features may be coincident with each other because this requires accurate alignment, accounting for positional tolerances, matching and overlay of data from ILI runs of different technologies and often from several years apart.
This paper describes an approach to identify where coincidental features occur within a pipeline by:
• Combining and overlaying multiple ILI technologies and data sets in a common interface.
• Allowing different proximity tolerances to be used to account for positional accuracy in the determination of coincident feature groups.
• Enabling the identification of the ILI reported features (e.g., cracks, internal and external corrosion, dents, mill faults including laminations, gouges etc.) that could be coincident and therefore may interact.
Case studies are used to illustrate the approach and to evaluate the results obtained.