Dynamic risk-based methodology for economic life assessment of aging subsea pipelines

Nowadays, numerous subsea pipelines reached their intended lifespan, necessitating the extension of their operational life to exploit the remaining oil and gas reservoirs. During the life extension phase, the economic viability of aging subsea pipelines becomes crucial. This paper presents a dynamic risk-based methodology for economic life assessment of aging subsea pipelines. The methodology integrates risk, cost, and profit factors to accurately estimate the economic life of pipeline. A Bayesian network (BN) model is constructed to assess the failure probabilities of subsea pipelines. Additionally, a maintenance model based on Bayesian influence diagram (BID) is developed to determine the maintenance cost while maintaining the pipeline failure risk at an acceptable level. The total cost of life extension is calculated by combining maintenance cost and pipeline failure cost. Ultimately, the economic life of pipeline is estimated based on the principle of maximizing profit throughout the pipeline's lifecycle. The methodology is demonstrated through a case study, and it can be a useful tool to guide the life management of aging subsea pipelines.