Subsea production facilities may be "over-designed" if the worst-case "Design" conditions are included in the Flow Assurance analysis as the most onerous cases usually have low frequency of occurrence. With new frontier developments and challenging project economics, over design is no longer acceptable as the "default solution". Risk-based flow assurance design employs a probabilistic analysis approach which allows for avoidance of over-design by quantifying key uncertainties and identifying major flow assurance risks through Monte Carlo simulations. Possible applications of risk-based decision making in flow assurance analyses include the sizing of flowlines, thermal insulation and surge capacity (slug catcher sizing), the determination of hydrate blockage formation likelihood, the definition of hydrate management strategy, the quantifying of hydrate inhibitor dosage requirement, and the optimisation of network systems.
In this paper, the application of probabilistic approach in the optimisation of flowline insulation requirement using a Risk Management and Optimisation (RMO) tool is discussed.
For a new phase of the B-field development (called "Phase 2" in this paper), new wells will be tied back to a new B-Manifold, and the fluids transported via a new insulated rigid CRA subsea flowline to an existing crossover manifold (A-XOM) where it is commingled with production fluids from the A-field. Combined production is transported via two existing Phase 1 flowlines to an offshore gas processing platform (GPP). Gas from the platform is subsequently sent to an onshore plant. A simplified field layout is provided in Figure 1.