成品油管道基于内检测的适用性评价与维修决策

目的建立成品油管道基于内检测的适用性评价及维修决策方法。方法针对某成品油管道内检测数据中的管道缺陷,进行缺陷尺寸特征与环焊缝关系等统计分析。考虑缺陷形态对管道安全运行的影响,结合国内外相关标准,制定成品油管道缺陷维修判定准则。结合缺陷强度评价、腐蚀速率计算以及剩余寿命预测,确定缺陷维修计划和再检测周期。结果该管道内外腐蚀较突出,管道外部腐蚀缺陷分布相对较为均匀,而内部腐蚀缺陷分布较为集中。通过腐蚀缺陷点与最近环焊缝距离分析,发现疑似焊缝处防腐层补口失效3处。经评价分析,该管道建议无立即修复缺陷,所有93处腐蚀类金属损失缺陷计划响应时间都在5年内。通过管道适用性评价、腐蚀缺陷剩余寿命预测,确定管道再检测时间间隔为5年。结论采用ASME B31G、分段腐蚀速率预测等方法实施管道完整性评价,并以此确定缺陷维修响应等级和时间具有较好的实施效果。当现场开展开挖修复工作后,应根据开挖测量结果修正管道缺陷维修计划。

The Fitness-for-service Assessment and Maintenance Decision-making of a Refined Oil Pipeline

A method for applicability evaluation and maintenance decision-making based on in-line inspection for refined oil pipelines is established. According to the pipeline defects in the inspection data of a product oil pipeline, statistical analysis of the relationship between the defect size characteristics and the girth weld is carried out. Considering factors such as the influence of combined defects and girth welds, and the characteristics of defects, the criteria for determining the defect maintenance of refined oil pipelines are formulated. Combined with defect residual strength evaluation, residual life prediction and comprehensive factor analysis, the defect maintenance decision is determined, and the next pipeline inspection time proposal is proposed. According to the statistics on the characteristics of pipeline defects, it is found that the internal and external corrosion of the pipeline is relatively prominent; the external corrosion defects of the pipeline are relatively uniform, while the internal corrosion defects are more concentrated. The analysis on the relationship between corrosion defects and girth welds reveals that there are three suspected welds with anti-corrosion coatings for the failure of the repair, and further excavation and verification shall be conducted. After evaluation and analysis, it is recommended that the pipeline does not need an immediate repair of the defects, and the planned response time for all 93 corrosive metal loss defects is within 5 years; considering the integrity of the pipeline, combined with the remaining life prediction results, the next inspection interval of 5a is suggested. The method of ASME B31G, segmented corrosion rate prediction and other methods are adopted to carry out pipeline applicability evaluation, and a better defect repair response level and repair time are determined with this. Furthermore, taking into account the complexity of the pipeline service environment and the limitation of detection accuracy, the defect repair plan should be revised based on the actual pipeline operation and the results of the excavation verification.