A New Discrete Slug-Flow Controller for Production Pipeline Risers

In this paper we propose a new discrete slug-flow control to stabilize severe slugging oscillations in submarine oil-risers. Since the practical objetive is to stabilize the flow keeping the surface choke with a minimum pressure drop, the idea of pressure set-point looses significance. One could say that the control problem is well solved if the pressures and flow-rates do not oscillate while the surface choke is kept opened well above the opening which characterizes the beginning of the limit cycle. The idea is to develop a control strategy which supres the oscillation while keeping the choke opening operating around a desired opening value. If the oscillations are suppressed the resultant pressures will be a consequence of the input mass flow-rate, fluid characteristics and the system geometry. Simulation results were obtained for a case study using a comercial software in order to validate the proposed control system.