Systemwide Optimal Control of Offshore Oil Production Networks with Time Dependent Constraints

Operating policies for oil production systems based purely on static behavior can incur excessive gas flaring and potentially violate environmental regulations, specially when the system undergoes transients in response to predictable and unanticipated events. On the other hand, optimal control strategies can reach an optimal steady state by accounting for the system dynamics, while handling the transients triggered by such events. This paper develops optimal control strategies for a representative class of offshore oil production systems that consist of a gas-lift injection system, subsea equipment, and surface processing units. The optimal control problems are solved with the collocation method, which discretizes time and uses polynomial interpolation to find a continuous-time solution. The collocation method results in a large, but sparse nonlinear programming problem which is solved with state-of-the-art algorithms for dynamic optimization. We show an application where the proposed method can be used to plan and schedule processing equipment maintenance.