Optimisation of the Flow Assurance Strategy for a HPHT Subsea Tieback

There was a desire to optimise the minimum acceptable flow rate for an existing HPHT gas-condensate tieback and to reduce the volume of hydrate inhibitor that is used during start-ups or restarts. Transient multiphase flow simulations were benchmarked against current operating data and were then re-run for the proposed future operating state to demonstrate that the system could be maintained outside the hydrate region for steady state and shut-in conditions. Compositional tracking simulations were performed to optimise the required inhibitor injection requirement (rate and duration) for restarts.