Frechet分布的海底油气管道腐蚀预测

应用Frechet极值分布建立管道最大腐蚀深度预测模型,然后用马尔科夫链蒙特卡罗(MCMC)方法估计预测模型的参数值,通过模型预测出可能的最大腐蚀深度,并结合钢质管道管体腐蚀损伤评价方法和马尔科夫链模型对管壁腐蚀的最大概率状态进行分析和预测,实现对海底油气管道腐蚀现状和运行情况的科学评价和预测。结果表明:管道腐蚀进入状态3以后,腐蚀速率加快,在管道运行到第10年时,就需要更换新管。该组合模型能够很好地预测油气管道的最大腐蚀深度和腐蚀状况,从而为合理确定管道的检测、维护、维修和更换周期提供科学的依据。

Corrosion Forecast of Offshore Oil and Gas Pipelines Based on Frechet Distribution

Frechet extreme distribution was used to establish for the maximum depth of corrosion pit,the values of parameters in the forecast model were estimated using Markov chain Monte Carlo (MCMC) method.By combining with the evaluation method of corrosion damage of steel pipelines and Markov chain model,forecasted maximum corrosion depths of pipelines,the maximum probability state of pipeline wall corrosion was analyzed and forecasted,so that the scientific evaluation and forecast on corrosion status and operation condition of offshore oil and gas pipelines could be realized.The results show that the corrosion rate will be accelerated when the pipeline enters the third state,when the pipeline runs to the tenth years,it will need to be replaced with a new tube.The combination model can well forecast the maximum depth of corrosion pit and the corrosion situation of offshore oil and gas pipelines,and provide a scientific basis for maintenance,repair and detection of the offshore pipelines.