As the global energy sector advances Carbon Capture, Transportation, and Storage (CCT&S) initiatives, repurposing existing gas pipelines for CO? transport offers a cost-effective and sustainable solution. This study presents a comprehensive feasibility and qualification assessment for converting a 30" x 220 km offshore gas export pipeline in Malaysia to transport dense-phase CO? from CCS hubs in Peninsular Malaysia to offshore depleted reservoirs.

The evaluation spans four key technical areas:

Fracture Toughness Qualification Due to missing manufacturing certificates, a statistical analysis of 5,000 data points from similar pipes was used to infer Charpy V-Notch (CVN) values. Results showed higher-than-standard toughness, except for a 5 km section (KP4–KP9), which requires replacement due to lower resistance under specific conditions. Corrosion Assessment Using OLGA simulations, corrosion rates were predicted based on CO? composition and operating conditions. No water dropout was observed under normal or blowdown scenarios, indicating minimal corrosion risk. Depressurization Impact Analysis The study assessed rapid depressurization effects on temperature, phase behavior, and solid formation risks. Simulations confirmed that a 6–7 day blowdown is feasible without breaching the pipeline’s minimum design temperature of 0°C. Dropped Object and Frequency Analysis A risk assessment using DNV-RP-F107 methodology evaluated threats from dropped and dragged anchors. Results showed that the risk of failure remains within acceptable industry limits, supporting the pipeline’s continued use.

The integrated findings demonstrate that, with appropriate material qualification, corrosion management, operational controls, and external risk mitigation, the existing export gas pipeline can be a viable approach to repurposed for CO? transportation. This work provides a robust technical framework and practical insights for similar repurposing projects, advancing the deployment of CCS infrastructure in Southeast Asia and beyond.