文昌油田群海底管线段塞流试验研究

Experimental Study on Slug Flow of Submarine Pipelines in Wenchang Oilfield

为消除严重段塞流对设备及油田生产的影响,以文昌油田群第二条输送线路为研究对象,建立模拟试验装置,对海底管道多相流的流动状态及参数变化等进行试验研究,分析了出现的各种流型特征。针对空气-白油(LP-14)-水多相流的流型图,研究了流型变化的机理,给出了严重段塞流发生的条件,并在此基础上分析了严重段塞流发生周期循环过程以及流动的周期长度、液塞长度、气液流出速度与入口气液流量的关系。研究结果表明:长液塞流出上升管时的速度会有一个突跃,对出口阀门以及捕集器等设备的冲击非常大;长液塞长度随着气相折算速度的增大而减小,随着液相折算速度的增大而增大;下倾角会加强严重段塞流,使段塞周期延长;在空气-水-油三相中,由于油的黏度和油气的强烈混合等因素导致油气水三相严重段塞流更加复杂;随着液相黏度的进一步提高,严重段塞流已经不易发生,若发生则其流量区域也明显减小;采用出口节流阀能有效控制严重段塞流的发生,但是1%的阀门开度会对出口节流阀性能造成巨大的影响,使其更加容易被破坏。研究结果可为进一步探索合理可行的消除严重段塞流的方法提供参考。

To eliminate the impact of severe slug flow on equipment and oilfield production,the second transportation line of Wenchang Oilfield Group is taken as the research object,and a simulation test device is established to study the flow state and parameter variation of multiphase flow in submarine pipeline.The various flow patterns observed are analyzed.For the flow pattern of air-white oil(LP-14)-water multiphase flow,the mechanism of flow pattern change is studied,and the conditions for the severe slug flow are given.Based on this,the severe slug flow cycle is analyzed.The effects of the length of the cycle,the length of the liquid plug,and the gas-liquid outflow rate on the inlet gas-liquid flow rate are also analyzed.The results show that there is a sudden jump in the velocity of the long liquid plug flowing out of the riser.And the impact on the outlet valve and the trap is very large.The length of the long liquid plug decreases as the gas phase conversion velocity increases,but increases with the liquid phase conversion velocity.The dip angle will strengthen the severe slug flow and prolong the slug cycle.In the air-water-oil three-phase,the severe air-water-oil three phase slug flow is more complicated due to oil viscosity and strong mixing of oil and gas.With the further increase of liquid viscosity,severe slug flow is not easy to occur,and its flow area is significantly reduced if it occurs.The use of outlet throttling can effectively control the severe slug flow.But a 1%valve opening has a substantial impact on the outlet throttle valve,making it more susceptible to damage.The study results can lay a foundation for further exploration of a reasonable and feasible method of eliminating severe slug flow.