Risk control of plugging operation without shutting down pipelines based on bow-tie model

In order to guarantee safety operation and meet process risk control requirements of special operations for pipeline maintenance and repair, it is necessary to study process risk control measures for holing and plugging operations without shutting down pipelines. In this paper, the principle and technological process of holing and plugging without shutting down pipelines were analyzed with the pipe replacement and line change of Zhuangxi external transmission pipeline of the Twelfth Oil Production Plant of Changqing Oilfield as an example. Afterwards, based on fault tree analysis, the reasons for fire and explosion of holing and plugging with nonstop transmission were discussed and the risk factors in the operation process were confirmed. And accident development process was shown using the event tree method. Then, the fire and explosion bow-tie model of holing and plugging with nonstop transmission was established. Fnally, the fire and explosion control measures for holing and plugging with nonstop transmission were put forward, i.e., fire and explosion suppression, emergency repair with fixtures, emergency shutdown of upstream valves, evacuation and medical care. It is demonstrated by the practical application that this model plays a guiding role in the safe operation of holing and plugging without shutting down pipelines and is practically significant to ensure the operation safety of holing and plugging in oil and gas pipelines.