The use of in-line inspection tools is today a standard procedure regarding the maintenance of high pressure pipelines. Inspection tools utilizing ultrasound technology have been successfully used for close to 20 years now and have proven themselves regarding their reliability, measurement accuracy and robustness of the data collected. Over the years the capabilities of this class of tools have been extended and today a large variety of special tool configurations are available to address the multitude of inspection requirements the pipeline industry has.
This paper will provide an overview of some of these special configurations of high resolution ultrasonic tools that have been development based on customer needs. Examples will be shown from a variety of case studies, describing the added value that the use of these tools provides.
The effect of increased resolution and measurement accuracy will be discussed and its effect on integrity assessment.
The examples covered include combination tools for metal loss and crack inspection, multi-technology tools for the inspection of gas pipelines, special configurations for the use in a high wax content environment, and finally the inspection for pitting and small localized corrosion features.