Intelligent pigging is the inspection of a pipeline from the interior of the pipe using an inline inspection tool/vehicle that deploys a Non-destructive Examination (NDE) technique to inspect the pipewall condition. This inspection vehicle is suitably configured to carry sensors, electronics and contain data recording facilities. It is constructed in segments to negotiate the pipeline bends and curvatures and is capable of passing through main line valves. Currently two NDE techniques are commonly used in the detection & characterisation of defects (primarily metal loss) in the pipeline: Magnetic Flux leakage and ultrasonics. Both the techniques have their limitations and advantages and high resolution tools based on either of the techniques are commercially available.

The pre-inspection requirement includes a thorough cleaning of pipe wall internal surface by using special cleaning pigs sot hat interpretable data is generated during the inspection. This paper aims at presenting an overview of the entire methodology including the basic principles, typical components/construction of an inspection vehicle, pre-inspection/during inspection requirements, inspection procedures, post inspection data evaluation, comparison of two techniques and limitations/benefits of application of this NDE technology.