山区高落差管道带压封堵施工工艺

Construction Process of Pipeline Hot Tapping and Plugging in Large-fall Mountainous Area

长输油气管道输送和运营维护过程中,经常会遇到需要更改走向或者管道出现问题需要更换等情况,此时就需要进行带压封堵作业。结合西南成品油北盘江跨越段油管道改线工程,对山区高落差管道带压封堵施工工艺进行分析,针对处于线路的最低点的跨越段管道内静压远远超出常规施工压力,以及停输时间有限的难点,采用"阶梯式"降压的方法,即设置四个封堵点,先进行两个外侧封堵点的单封单堵,后进行中间两个封堵点的双封双堵,将高静压施工变为常规压力施工,最终改线工程顺利完成,为类似工程提供借鉴。

In the process of oil/gas transportation,operation and maintenance of long- distance pipeline,it is often encountered that the pipeline needs relocating or replacing.In these cases,the work of hot tapping and plugging is required.Combined with the Beipan River pipeline crossing section relocation project,the construction process of pipeline hot tapping and plugging in large- fall mountainous area is analyzed in this paper.The pipeline crossing section is located in the lowest position of the pipeline,its internalpressure is far beyond the conventionalpipeline construction pressure,and another problem is the limited shutdown time.So the method of ＂reducing pressure step by step＂ is adopted,which sets up four plugging points,i.e.firstly,hot tapping and plugging at two outsides points in the section,then at two inside points.Thus,the pipeline relocation construction under high pressure is turned into under conventional pressure and is successfully realized.