Subsea pipelines network represents a key component of oil and gas offshore operations, thus determining the integrity status for each pipeline to ensure a safe, reliable and cost-effective operation is crucial. It is always difficult to regularly check pipelines of tremendous length and large diameter, which are frequently laid in places that are not easily accessible. This paper presents a risk assessment model developed as part of a holistic study conducted to evaluate the condition of subsea pipelines. A systematic semi-quantitative risk-based model was developed to identify, analyze and evaluate risk associated with each subsea pipeline. The risk calculation combines the Probability of Failure (PoF) and the Consequence of Failure (CoF). The PoF calculations considered different factors, which believed to have direct impact on the likelihood of pipelines failure including: internal corrosion, hydrogen induced cracking (HIC) susceptibility and mechanical integrity. The CoF calculations factor safety, environment, economic and reputation impact. In overall, the study determined the risk level of each pipelines and provided measures and recommendations to lower the total risk.
Key words: Corrosion, risk, subsea, offshore pipeline, Probability of Failure (PoF), Consequence of Failure (CoF), Inline Inspection (ILI).