WIT Press

Two-phase Flow Transient Simulation Of Severe Slugging In Pipeline-risers Systems


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G. Hernández, M. Asuaje, F. Kenyery, A. Tremante, O. Aguillón & A. Vidal


Pipeline-risers systems are frequently encountered in the petroleum industry, especially in the offshore platforms. Single-phase flow does not involve significant troubles in the operations through these arrangements. However, during multiphase flow, flooding of the separation facilities could be expected due to the generation of severe slugs at the bottom of the riser. The size and frequency of the slugs are functions of the accumulation and displacement of liquid at the base of the riser and can be controlled with an adequate model. An improved transient model is presented to simulate severe slugging phenomenon in pipeline-risers systems. Gas penetration is described thoroughly since the first bubble penetrates into the riser until it reaches the top of it. The model presents improvements in the characteristics method applications including a correction for the gas density deviation caused by the nonfixed space-time resolution during the gas penetration. The results were compared with experimental data and previous models showing better accuracy. The model can be used to design new pipeline riser-systems or to adjust the operation of existing systems to prevent the occurrence of severe slug flow. Keywords: two-phase flow, pipeline-risers systems, transient model, severe slugging. 1 Introduction Severe Slugging process is well known for disturbing operations in pipelinerisers systems due to the production of long liquid slugs in a short period of time, causing flooding of the separation facilities downstream. It occurs when the liquid and gas superficial velocities are relatively low to maintain stratified flow in the pipeline. Once the liquid intends to climb through the riser, the gravity


two-phase flow, pipeline-risers systems, transient model, severe slugging.