Small scale severe slugging experiments with several risers

Severe slugging is a multiphase flow phenomenon that can occur in flowline-riser systems when conditions allow it. Its periodical fluctuations in pressure and mass flow can cause operational problems in downstream processing facilities, and should be avoided. The occurrence of severe slugging in parallel riser systems is of interest due to the increasing need of subsea flow splitting during hydrocarbon production. To investigate that issue, this work involves experiments done one a small-scale facility applying air and water to simulate a two-phase flow. Different geometries with dual risers are studied both symmetrical and non-symmetrical. Pressure and flow rates have been recorded and registered in combination with visual observations. This in order to produce flow regime maps, as well as looking at changes in period and pressure amplitude. Efforts were made towards stabilizing a severe slugging regime by using different sized risers. The results showed that adding a thinner riser had some success in stabilizing severe slugging in a non-symmetrical dual riser system. A symmetrical system did however not respond to this approach. The results give reason to recommend further research in the matter of dual risers. Improvements of the facility, or by moving on to a larger experimental loop, can allow for better flow control, added measurements of the actual phase split and potential stability options, such as the thinner riser tested in this study