基于失效数据的油气管道定量风险评价方法

油气管道风险评价作为当前的热点问题,逐渐由定性评价向定量评价过渡。为了减少油气管道定量风险评价过程中主观因素的影响,建立了基于管道失效历史数据的油气管道定量风险评价模型,通过分析美国管道与危险品安全管理局(PHMSA)等数据库的管道分类失效数据,确定了油气管道的基本失效概率与修正因子的指标体系,再根据各个指标量化的难易程度将修正因子分为定量、半定量及定性3种类型,其中前两类指标可以量化或量化分级,仅后一类指标依赖于专家的经验判断,大大降低了风险评价的主观依赖性。进一步构建了油气管道风险评价矩阵,用失效概率量化失效可能性,用后果评分量化失效后果的严重程度。最后,将该油气管道定量风险评价方法应用于某输气管线,并绘制"红橙黄蓝"4色管线风险分布图,识别出该管线的高风险管段。结论认为:(1)基于管道失效历史数据的风险评价方法能够客观地量化管道的失效概率,准确进行风险分级,有利于实施风险分级管控策略;(2)建议建立全行业或全国范围的管道失效数据库,以期为基于历史数据的定量风险评价乃至制订风险管控措施提供依据。

A quantitative risk assessment method for oil and gas pipelines based on failure data

The risk assessment of oil and gas pipeline, one of the current hotspot issues, has gradually evolved from qualitative evaluation to quantitative evaluation. In order to reduce the effects of subjective factors in the process of quantitative risk assessment of oil and gas pipeline, we established a quantitative risk assessment model of oil and gas pipeline based on the historical data of pipeline failure. The index system of basic failure probability and modification factors for oil and gas pipeline was determined by analyzing the failure data of different types of pipelines in the database, such as Pipeline and Hazardous Materials Safety Administration (PHMSA). The modification factors are divided into three groups (i.e., quantitative index, semi-quantitative index and qualitative index) according to the degrees of difficulty in quantifying the modification factors. The first two groups of them can be quantified or quantitatively classified, and only the last one depends on the experience of experts. Thus, the subjective dependence of risk assessment is reduced greatly. Then, the risk evaluation matrix of oil and gas pipeline was constructed, the likelihood of pipeline failure was quantified by using the failure probability, and the severity of the failure consequence was quantified by means of the consequence score. Finally, this quantitative risk assessment method was applied to one gas pipeline system, and a four-color (red, orange, yellow and blue) risk distribution map was plotted to identify the high risk pipe segments. It is included that the risk assessment method based on the historical data of pipeline failures can quantify the failure probability of the pipeline objectively, and classify the risk accurately, which is conducive to the implementation of classification based risk control strategy. It is recommended to create the pipeline failure database in the whole industry or all over the country, so as to provide a basis for the quantitative risk evaluation based on historical data and even for the formulation of risk control measures.