An online Flow Assurance Simulator (FAS) has been developed for the Åsgard subsea compression (ÅSC) system, which boost the production from the Mikkel-Midgard gas condensate fields. The production is tied back to the Åsgard B platform. The FAS, which is configured in Watch FlowManager™, provides information of the operational process and multiphase flow conditions through the wells and templates, subsea compression station, import/export flowlines and topside separation system.
The flowline model in the FAS has been tuned against existing field data on pressure drop and liquid accumulation. At low flow rates, liquid surge wave instabilities in the flowlines occur. In the present paper, it is shown that the tuned flow model capture these surge waves. The model predicts that the water surge comes from the riser, while the condensate surge comes from the flowline. Details of the predictions of surge build up and release are given.
The FAS is a production operation and planning tool mainly used by Åsgard operational support for liquid management and hydrate control. To demonstrate the FAS performance during a real-time operation, a comparison between the FAS and the field measurements during a restart after a system turnaround is presented. It is shown that the Åsgard FAS captures the transient behaviour quite well.