基于TVR的腐蚀油气管道失效概率及安全寿命研究

为避免因腐蚀导致油气管道失效，针对因管道特性和腐蚀尺寸的不确定性使得管道剩余强度成为概率模型的特点，建立了腐蚀管道强度损失随机模型；借助可靠性理论，通过分析管道腐蚀进程的时变性特点，将管道系统由损伤积累和抗力衰减导致的剩余强度随机化；提出基于穿越率的腐蚀油气管道失效评定及安全寿命预测方法。研究结果表明:腐蚀速率和运行压力对管道失效概率及安全寿命影响显著,管道尺寸影响适中，而相关系数和拉伸强度影响较小；若腐蚀速率Va=0.2 mm/a，VL=10 mm/a或局部腐蚀缺陷半径达到管道壁厚的0.5倍时，建议作为重点风险段监测并检修。所建方法是对腐蚀油气管道运营监控和风险评估的有益补充。

Research on failure probability and safe life of corroded oil and gas pipelines based on TVR

In order to avoid the failure of oil and gas pipelines caused by the corrosion, aiming at the characteristic that the uncertainties in pipeline characteristics and corrosion size actuate the residual strength of pipeline to be a probabilistic model, a stochastic model on the strength loss of corroded pipeline was established. Based on the reliability theory, the residual strength of the pipeline system caused by the damage accumulation and resistance attenuation was randomized through analyzing the time varying characteristics of the corrosion process of pipeline. The methods of failure assessment and safe life prediction for the corroded oil and gas pipeline based on the passage rate were proposed. The results showed that the corrosion rate and operating pressure had significant effect on the failure probability and safe life of pipeline, and the effect of pipeline size was moderate, while the effect of correlation coefficient and tensile strength were less. If the corrosion rate Va=0.2 mm/year, VL=10 mm/year or the radius of local corrosion defect reached 0.5d, it was recommended to monitor and repair as the key risk section. The method is a useful supplement to the operation monitoring and risk assessment of corroded oil and gas pipelines.