Abstract: S-sharped riser, one of the main structures in deep-water gathering system, runs frequently into typical severe slug flow at small liquid and gas rates, which show a great destroy on downstream devices.In this work, the classification and flow characteristic of severe slug flow are studied.The result shows that:①Like in the L-shaped riser, the severe slug flow in S-shaped riser displays strict periodicity, and the formation process covers five stages, namely, liquid slug formation in down limb, liquid slug formation in up limb, liquid production, gas blowout stage and liquid fallback.②The cycle and liquid slug length of typical severe slug flow decrease with the increased gas and liquid rates.③The composition of fluid mixture doesn't make much difference on the performance of severe slug flow.④The hazard of severe slug flow goes up with the diameter or/and height of the riser; Once the severe slug flow occurs to the deep-water oil & gas large diameter gathering system, the overwhelming damage could take place.⑤The cycle of severe slug flow rise with the operating pressure of separator, which could cause a more serious consequences.

Key words: deep-water, gathering system, S-shaped riser, periodicity, liquid holdup

摘要： 对深海油气集输主要形式之一的S形立管出现的严重段塞流进行了分类和流动特性的分析,得到关键参数对该系统的影响情况,主要形成如下结论:①S形立管典型严重段塞流同L形立管一样具有严格的周期性,其形成过程可分为5个阶段,即下肢液塞形成、上肢液塞形成、液塞溢流、液塞喷发和液塞回流;②随着输量增大,严重段塞流的周期和液塞长度均减小,周期规整性有所减弱;③油气组成在较小范围内变动,对典型严重段塞流的影响不大;④增大管径或立管高度增大了严重段塞流的危险程度,大管径的深海集输管线一旦发生严重段塞流,将产生严重的后果;⑤随着分离器压力的增大,段塞周期增大,发生严重段塞流的后果越严重。

关键词: 深海, 油气集输, S形立管, 周期性, 持液率