Integrated Model Based Control of Topside Process and Production Wells

Abstract

In offshore production systems for oil and gas, the wells are usually controlled manually, while the topside process is controlled using a decentralized control system. It is clear that this control structure may not be economically optimal. In the work of this thesis, one decentralized and two MPC based control systems were designed, integrating the control of the production wells and the topside process of an offshore production system. The performance of the controllers was tested in a simulation study with three different disturbance scenarios, defined in collaboration with Hydro. The simulations were also carried out using a manual control scheme, enabling a performance comparison between the designed controllers and the control conventions of today. The automatic controllers showed a significant increase in oil throughput over the manual control scheme, while performing quite similarly when compared to each other. It is however expected that the MPCs will outperform the decentralized control system in a case with a larger number of wells than was used in the simulations of this thesis. The potential of achieving additionally smoothened topside outflow rates by applying a supervisory MPC for topside setpoint manipulation was also demonstrated.