Abstract:

During the exploitation of offshore oil，it is easy to form severe slugging in the riser system at a low gas-liquid velocity.The magnitude of the pressure fluctuation can be significantly high，causing dramatic change of flow rate and leading to other damages.In this paper，the characteristics of slug velocity during the four stages of severe slugging in the pipeline-riser system were studied.It was found that the slug head rose in the riser at a constant velocity in the slug formation stage.At the same time，the direction of slug tail movement was opposite to the flow direction，and the tail velocity kept constant when flowing through the inclined pipe.In the process of blowout，the liquid velocity in the pipeline-riser system increased and reached a maximum value when the slug tail reached the top of the pipeline-riser.At this moment，the instantaneous flow rate was much larger than that in the slug production stage.