射流清管器结构参数与清管积液运移特性

Structural parameters of bypass pig and movement characteristics of liquid loading in the process of pigging

明确清管器结构参数对射流清管器运行规律及射流效果的影响,对于保障管道流动安全、顺利完成清管作业尤为重要。对某实际天然气凝析液管道进行清管模拟,分析清管器旁通率、摩擦力等结构参数对其运动特性及清管段塞的影响,并研究凝析液和液态水在射流清管过程中运动规律的差异。结果表明:射流清管器平均速度随旁通率的增加呈线性下降趋势,旁通率增加可以显著降低清管段塞量,平缓气量波动;摩擦力对模拟结果具有重要影响,若模拟前清管器摩擦力计算偏小,将导致清管段塞的预测值大幅增加;液态水和天然气凝析液在射流清管过程中的运动特性差异较大,液态水的存在会一定程度上削弱射流清管效果。

To ensure pipeline flow safety and carry out pigging operation smoothly, it is of great significance to figure out the effects of structural parameters of bypass pig on its movement laws and cleaning effectiveness. In this paper, pigging simulation was carried out on an actual natural gas condensate pipeline. The effects of the structural parameters（e.g. bypass fraction and friction force） of bypass pig on its movement characteristics and pigging slug were analyzed. Besides, the difference of movement laws between the gas condensate and the liquid water in the process of bypass pigging was studied. It is shown that with the increase of bypass fraction, the average velocity of bypass pig decreases linearly, the pigging slug volume drops remarkably and gas rate fluctuation is flattened. The friction force has a great impact on the simulation results. And the predicted pigging slug will increase greatly if the friction force of the pig before the simulation is underestimated. The movement characteristics of liquid water and gas condensate in the process of bypass pigging differ a lot, and the existence of liquid water can to a certain extent, weaken the effectiveness of bypass pigging.