考虑腐蚀缺陷的管道内检测周期优化方法

内检测是进行风险识别,保障油气管道安全运行的重要手段。为了平衡风险与成本,确定最优的腐蚀管道内检测周期,提出了基于成本的以失效概率阈值为决策变量的内检测周期优化方法。利用蒙特卡罗仿真技术计算了管道的可靠性和总成本率,以最低总成本率确定管道最优失效概率阈值,从而得出最优内检测周期。采用某天然气管道的实际数据对提出的方法进行了论证和敏感性分析,结果显示最优内检测周期随着缺陷初始深度和缺陷深度生长速率的增大而减小,缺陷初始深度变异系数和失效成本对最优内检测周期无显著影响。所提出方法可以在风险和成本之间寻求平衡,有效地确定腐蚀管道的最优内检测周期,能定量评价腐蚀缺陷相关参数对管道内检测周期的影响,具有一定的先进性。

Optimization Method of Pipeline Inspection Period Considering Corrosion Defects

Internal inspection is an important means to identify risks and ensure the safe operation of oil and gas pipelines.A cost-based optimization method with a failure probability threshold as a decisive variable is proposed to balance risk and cost,and determine the optimal internal inspection period.By Monte Carlo simulation,the authors first calculated the reliability and total cost rate of a pipeline,and estimated the optimal failure probability threshold at the lowest total cost rate to obtain the optimal internal inspection period.The method has been tested by the actual data of a natural gas pipeline.The results show that the optimal internal inspection period decreases with the increase of the initial defect depth and the growth rate of the defect depth;the variation coefficient of the initial defect depth and failure cost have no significant effects on the optimal internal inspection period.The method proposed can make a balance between risk and cost,effectively determine the optimal internal inspection period of corroded pipelines,and can quantitatively evaluate the influences of corrosion and defect parameters on the internal inspection period.The method is advanced to some extent.