Flooding Simulation of Hilly Pipeline Commissioning Process

The “pipeline flooding process”, refer to filling the empty pipe with water or oil when basic facilities’ construction of a pipeline has been completed, is very important for pipeline commissioning. The pipeline flooding process becomes more complicated for the long-slope pipe segments of a hilly pipeline because of air entrapped in fluid. The accumulated air in the fluid which is called air pocket can cause significant damage on pump equipments. The existence of air pocket can also provide difficulties for tracking the fluid front and the interface between oil and water because of the effect of air pocket on the velocity profile of fluid. To avoid such difficulties, the only method is to efficiently discharge the accumulated air. Consequently, the location and the volume of air pocket need to be accurately predicted. In this study, a comprehensive two-fluid model was developed for this prediction using the fundamentals of mass balance and momentum transfer in multiphase flow. By taking into account the effect of air pocket, the location and velocity of flooding front, the pressure at each point in the flooding segment can also be calculated. Therefore, the prediction accuracy of this model can be estimated by comparison with the recorded pressure distribution of SCADA. The model was applied for a specific pipeline in China. In comparison with the SCADA data, an adequate prediction from this model was provided.