The Impact of Riser-induced Slugs on the Downstream Deoiling Efficiency

In Oil and gas productions, the severe slug is an undesired flow regime due to the negative impact on the production rate and facility safety. This study examines the severe riser-induced slugs’ influence on a typical separation process, consisting of a 3-phase gravity separator physically linked to a deoiling hydrocyclone. Four inflow scenarios are compared: Uncontrolled, open-loop, feasible, and infeasible closed-loop anti-slug control, respectively. Three PID controllers’ coefficients are kept constant for all the tests: The separator pressure, water level, and hydrocyclone pressure-drop-ratio (PDR) controllers. The simulation results show that the separation efficiency is significantly larger in the closed-loop configuration, probably due to the larger production rates which provide a preferable operation condition for the hydrocyclone. It is concluded that both slug elimination approaches improve the separation efficiency consistency, but that the closed-loop control provides the best overall separation performance.