起伏地形湿气管道清管策略分析与研究

Analysis and research on pigging strategy of associated gas pipeline in undulating terrain

某油田经三相分离器分离出的湿气(伴生气)通过管道运送至中央处理厂进行深度处理,通过模拟发现下游生产分离器不能处理清管过程中产生的积液。针对这一问题,对影响管内积液量的因素进行了分析,对4种不同的吹扫和清管方案进行了模拟,最后得到合理的清管方案:先保持稳定运行1 d,随后将输量从4500 m^3/h增加到6500 m^3/h,在下入清管器同时将管道出口压力提高到5 MPa,并将输量恢复到4500 m^3实施清管作业。该方案使管内积液量大幅降低,同时保证了吹扫和清管过程中出口段塞量小于生产分离的有效工作容积,为现场的清管作业提供了技术支撑。

The associated gas separated by a three-phase separator from an oilfield was transported to the central processing plant by pipeline for deep treatment.Through simulation,it was found that the downstream production separator could not deal with the accumulated liquid generated in pigging process.In view of this problem,the factors affecting the amount of liquid in the pipeline were analyzed,and four different purging and pigging schemes were simulated.Finally,a reasonable pigging scheme was obtained:keeping stable running for 1 d,then increasing the throughput from 4500 m^3/h to 6500 m^3/h for 1 d,setting down the pig and meanwhile increasing the outlet pressure to 5 MPa and restoring the throughput of 4500 m^3/h,and starting pigging.The scheme greatly reduces the amount of accumulated liquid in the pipeline,and ensures that the outlet slug is less than the effective working volume of the production separator in the process of purging and pigging,which provides technical support for the field pipeline pigging operation.