Coupling Subsea Asset Risk Based Inspection to Logistic Optimization

The ultra-deep-water exploration and production of oil and gas require the installation of complex subsea assets such as flexible risers, flow lines, manifolds, well heads, etc. The structural integrity of these assets is monitored trough a costly repetitive inspection process involving a fleet of Remote Operated Vehicles (ROVs) and ROV supply vessels. The Risk Based Inspection (RBI) may be applied to partially mitigate some of these costs. However, there is still space for improvement coupling RBI to offshore logistic optimization. This paper presents a new methodology that minimizes the operating costs and the risk of failure of subsea assets involved in the O&G industry. A Discrete Event Simulation (DES) model is used to simulate the supply vessel fleet and inspection operations whereas an RBI model assess the risk of failure of the subsea assets. Variations of the interest variables is systematically performed to find the best solution. The results show a huge potential of reducing costs while maintaining the structural integrity of the equipment’s. In parallel, the model may give interesting insight on the optimal fleet size, chartering contract types, and on the best inspection strategy for a specific offshore field. The coupling of the RBI with logistic optimization seems promising to drastically improve the efficiency of the inspection and monitoring of O&G subsea assets in Brazil.