某山区油气管道废弃处置设计与实践

Design and practice of disposal of abandoned oil and gas pipelines in a mountainous area

目前国内油气管道废弃处置技术主要针对普通管道,对于大落差、地形起伏大的山区管道尚未见有关文献报道。以某山区油气并行管道为例,结合管道敷设特点及其周围环境,对比分析了全部拆除、全部注浆与分段处置方案的优缺点,优选工程量较小、施工成本适中、处置针对性强的分段处置方案作为最终实施方案并开展现场处置。结果表明:原油管道清洗的重点在于防止下坡段管道产生不满流,可通过低点注入清洗剂、严格控制清洗列车前后压差予以避免;油气管道拆除需综合考虑地形地貌、交通条件、施工技术、环境保护等因素,重点防止管道切割时应力释放伤人、残留油气燃爆、残留物污染环境;管道注惰性气体封存的分段隔离间距应在相关规定基础上适当减小;管道注浆封存时应结合实际具体提出浆液流动性、填充度、固化时间、结石强度等指标,同时严格控制浆液前端清管器运行速度,以确保注浆质量。

At present,the domestic disposal technology of abandoned oil and gas pipelines is mainly aimed at ordinary pipelines.For oil and gas pipelines in mountainous areas with large drops or large topographic undulations,the abandonment disposal technology has not been reported.Taking the parallel oil pipeline and gas pipeline in a mountainous area as an example,combined with the characteristics of pipelines laying and surrounding environment,the advantages and disadvantages of the schemes of all dismantling,all grouting and segmental disposal were compared and analyzed.The segmental disposal scheme with small amount of work,moderate construction cost and highly targeted disposal was selected as the final implementation scheme,and on-site disposal was carried out.The results show that the difficulty of the crude oil pipeline cleaning is to prevent the slack flow in the downhill section,and this can be avoided by injecting cleaning agent at low point and controlling the differential pressure between front and rear of the cleaning train.The dismantlement of the oil and gas pipelines should take into account such factors as landform,traffic condition,construction technology and environmental protection,and it's important to prevent stress release causing injury,residual oil and gas burning or explosion and residual pollution to the environment in pipeline cutting operation.For the isolation distance of oil and gas pipelines with injected inert gas in mountainous area should be reduced appropriately on the basis of relevant regulation.During the grouting of oil and gas pipelines in mountainous area,the indexes such as slurry fluidity,filling degree,solidifying time and stone strength should be put forward in combination with the actual conditions,and the running speed of the pig in front of slurry should be strictly controlled.