This paper presents a history match of the startup conditions measured for a buried offshore North Sea oil flowline. Wellhead and Platform-arrival temperatures, pressures, and flow rates were predicted as the production rate varied during startup. The simulation study was performed with the new workstation version of OLGA(R) (Version 1.4), a transient and steady-state multiphase-fluid-flow simulator. The OLGA simulator rigorously models the transient hydraulic and heat-transfer effects that occur during flowline startup. The effects of surface production devices, such as variable area chokes, were included in this study. Results from steady-state and transient runs are compared with field data. Good agreement was obtained between field and predicted values. This study also illustrates the importance of the phase behavior of the oil, fluid properties, and heat transfer on the simulation performance. Simulated steady-state results compared favorably with results predicted by PIPEPHASE(R), a steady-state multi-Phase-flow simulator.
