This 5 Km 10'' heavy oil offshore pipeline operates in a high temperature working condition (80-90°) with 12.7mm wall thickness since 2013. Due to the limit space on the offshore platform and unknown pipeline fitting information, which leads the high risk of running ILI tools, so that this line never had any ILI since the operation time.

After the pipeline information survey in detail, the R&D Centre customized the eddy current ILI tool by designing the length to 470mm suitable for the short (non-standard) pig traps. In addition, this special eddy current ILI tool also equipped with the electronic hardware and the eddy sensors that can detect heavy pipe wall thickness. As a result, after one time run, the ILI tool received successfully and gained high quality data outcome, which solved the difficulty of “Unpiggable”.

This inspection revealed a total of over 1,000 unit of metal loss, with numerous defects exhibiting a depth exceeding 30%wt. Through analysis, patterns of defects under the operational conditions of the owner's target pipeline were identified. Tailored improvement recommendations were proposed, assisting the owner in overcoming a decade-long challenge of not conducting ILI. Furthermore, a comprehensive understanding of the internal corrosion conditions of this subsea pipeline was established, providing crucial data support for subsequent safe operations.