In 2025, Ørsted and Baker Hughes collaborated to perform a technically demanding in-line inspection of a 302 km subsea pipeline, building on a previous 2017 inspection.
As part of its green energy transition strategy, Ørsted is evaluating the pipeline’s suitability for future CO₂ service. An increase in production in Spring 2025 presented an ideal opportunity to gather the ILI data needed to assess the feasibility of CO₂ re-qualification.
To maximise the value of the inspection, Ørsted expanded the scope to include XYZ mapping alongside MFL technology. This was to enable both anomaly detection and spatial analysis of pipeline geometry, which would demonstrate the effectiveness of its pipeline management system to Ørsted’s stakeholders.
The inspection presented two major challenges. First, the extremely low flow rate of approximately 0.2 m/s required the MFL tool to operate continuously for over 400 hours, demanding exceptional battery life, tool reliability, and data storage capacity. Second, the pipeline contained a subsea wye piece, a complex geometric feature that posed a significant risk of tool entrapment. Ørsted and Baker Hughes undertook detailed engineering analysis and risk mitigation planning to ensure safe tool passage.
The MFL tool was tasked with identifying a wide range of anomalies, including metal loss, dents, ovalities, girth weld anomalies, bends, and other ID reductions. These findings were compared against 2017 inspection data to assess asset condition over time. XYZ mapping enabled detection of local out-of-straightness, providing insight into potential ground movement or third-party interference, critical for long-term integrity management.
This paper presents the technical strategies, planning methodologies, and collaborative practices that enabled the inspection’s successful completion. It also shares key lessons learned and discusses implications for future long-duration and geometrically complex pipeline inspections. The case study offers valuable insights for pipeline operators, integrity engineers, regulators, and ILI vendors operating in similarly constrained environments.