Study On The Prediction And Flow Characteristics Of Severe Slugging In Pipeline-Catenary Riser System Of Deep-sea Oilfield

The pipeline-catenary riser gathering has gradually become the main gathering and transportation process of deep-sea oil and gas field production,Severe slugging severely restricts the gathering and transportation process and normal production.Such severe and unstable flow will cause the pipeline to oscillate violently,making the pipeline prone to fatigue fracture and causing the separator to overflow.In severe cases,the pump will undergo severe cavitation and the back pressure will rise to cause production stoppages or dead wells.It is particularly important to conduct in-depth research on severe slugging.Taking the Tupi deep-sea oilfield in Brazil as the research background,the numerical simulation method was adopted to solve the problem of inducing factors and uncertain timing of serious slugging in the deep-sea pipeline-catenary riser oil and gas transmission system.From the point of view of production parameters and structural parameters,the OLGA software was used to simulate the severe slugging flow.The results show that the amount of gas liquid transport,water content,and gas-liquid ratio in the production parameters all have a great influence on severe slugging flow.The impact of the results is different;the diameter of the pipe in the structural parameters and the angle of the pipeline have a greater influence on the severe slugging flow,while the thickness of the insulation has little effect on severe slugging.According to the numerical simulation results,the flow pattern of the fluid in the pipeline-catenary riser is given.The flow patterns of the severe slugging flow in the initial stage of the oilfield production are obtained by taking the flow rate and gas-liquid ratio as influencing factors.Theoretical research methods were used to establish a purely mechanical dynamic model for predicting severe slugging cycles based on momentum conservation equations,mass conservation equations,and gas state equations.The Brill,Schmidt and Tiller experiments and field data were used to verify the model.The results show that the mathematical model can not only accurately predict the cycle of serious slug flow patterns in the pipeline-catenary riser system,but also A good explanation of how the traditional severe slugging prevention and control methods can exert an inhibitory effect.This paper studies the inducing factors,timing of generation and flow patterns of severe slugging in the pipeline-catenary riser oil-gas mixture transportation system,and plays an important role in theoretical research and prevention of severe slugging flow patterns.The prevention and treatment of severe slugging in the production process provides theoretical guidance and has certain engineering application value.