A model for predicting failure of oil pipelines

Oil and gas pipelines transport millions of dollars of goods everyday worldwide. Even though they are the safest way to transport petroleum products, pipelines do still fail generating hazardous consequences and irreparable environmental damages. Many models have been developed in the last decade to predict pipeline failures and conditions. However, most of these models were limited to one failure type, such as corrosion failure, or relied mainly on expert opinion analysis. The objective of this paper is to develop a model that predicts the failure cause of oil pipelines based on factors other than corrosion. Two models are developed to help decision makers predict failure occurrence. Regression analysis and artificial neural networks (ANNs) models were developed based on historical data of pipeline accidents. The two models were able to satisfactory predict pipeline failures due to mechanical, operational, corrosion, third party and natural hazards with an average validity of 90% for the regression model and 92% for the ANN model. The developed models assist decision makers and pipeline operators to predict the expected failure cause(s) and to take the necessary actions to avoid them.     

Condition-based maintenance decision support system for oil and gas pipelines

The 2013 report card of America's infrastructure has scored the condition of oil and gas pipelines as D+ which means that such pipelines are in a relatively poor condition. More than 10,000 failures have been recorded in the US. These failures have resulted in environmental, health and property damages. Therefore, there is a definite need to give more attention to the maintenance of oil and gas pipelines. This paper develops a comprehensive model for the maintenance planning of oil and gas pipelines. The model selects rehabilitation/repair alternatives for oil and gas pipelines based on their condition during their service life. These alternatives are then used to calculate the cash flow throughout the service life of these infrastructures. The model, which uses Monte Carlo simulation and fuzzy approach to address the uncertainties in the estimation of the maintenance operation costs and the economic parameters, calculates the Equivalent Uniform Annual Worth of the identified alternatives. The optimum maintenance programmes consist of the alternatives that have the lowest life cycle cost of oil and gas pipelines. The model is expected to support pipeline operators in the maintenance decision-making process of oil and gas pipelines.     

Probabilistic Neural Network for Reliability Assessment of Oil and Gas Pipelines

A fuzzy artificial neural network (ANN)–based approach is proposed for reliability assessment of oil and gas pipelines. The proposed ANN model is trained with field observation data collected using magnetic flux leakage (MFL) tools to characterize the actual condition of aging pipelines vulnerable to metal loss corrosion. The objective of this paper is to develop a simulation-based probabilistic neural network model to estimate the probability of failure of aging pipelines vulnerable to corrosion. The approach is to transform a simulation-based probabilistic analysis framework to estimate the pipeline reliability into an adaptable connectionist representation, using supervised training to initialize the weights so that the adaptable neural network predicts the probability of failure for oil and gas pipelines. This ANN model uses eight pipe parameters as input variables. The output variable is the probability of failure. The proposed method is generic, and it can be applied to several decision problems related with the maintenance of aging engineering systems.     

基于KPCA-FA-ELM 模型的管道剩余寿命预测

针对管道剩余寿命的预测问题,提出了一种基于KPCA-FA-ELM组合模型的预测方法,对腐蚀管道剩余寿命预测模型的构建方法以及预测模型的性能验证方法进行研究。以我国某油田的回注水管道和油气集输管道为例,对本次研究所提出的管道剩余寿命预测方法进行验证。研究表明：本次研究所提出的KPCA-FA-ELM模型在进行油田注水管道剩余寿命预测过程中,其最小相对误差为0.38%,最大相对误差为6.1%,平均相对误差为2.35%,均方根误差为0.207,希尔不等系数为0.011,在进行油气集输管道剩余寿命预测过程中,其评价指标均小于其他模型,因此,该种模型的性能优于其他常见预测模型。     

埋地燃气管道失效风险的时间效应预警模型

埋地燃气管道失效风险预警在制定防控预案保障管道安全运行中占据重要地位,为提高多因素影响下埋地燃气管道的失效风险预警水平,提出埋地燃气管道失效风险的时间效应预警模型。该模型将管道失效风险的时间效应纳入失效预警体系构建中,采用灰色系统理论分析埋地燃气管道失效影响因素的时间效应,开发多因素影响下的综合失效概率时间效应预测模型并应用失效概率转换函数将估计失效概率转换为年失效概率,实现燃气管道失效风险级别与预警等级的快速判定。作为实例将该模型应用于常州市埋地燃气管道的失效风险预警,结果证明该模型高效可靠。     

埋地燃气钢管腐蚀检测及防腐对策

阐述了埋地燃气钢管防腐的重要意义,通过对某管道燃气公司埋地燃气钢管腐蚀检测,分析了产生腐蚀的原因,提出了减缓腐蚀的方法与对策,对该公司的外加电流深井阳极阴极保护法的防腐实践进行总结与探讨.     

里地燃气钢管腐蚀检测及防腐对策

阐述了埋地燃气钢管防腐的重要意义,通过对某管道燃气公司埋地燃气钢管腐蚀检测,分析了产生腐蚀的原因,提出了减缓腐蚀的方法与对策,对该公司的外加电流深井阳极阴极保护法的防腐实践进行总结与探讨。     

管线穿越山区河流的防护措施

长距离输油气管道和光缆等管线属于长线路工程，必然地会穿越一些山区河流，而且多为挖沟浅埋铺设，洪水和泥石流可能会造成管线外露和弯曲折断等严重后果。根据忠武输气管道工程的一些实例，分析山区河流可能对管线带来的危害或潜在危害，探讨安全合理的穿河段防护工程措施。     

遥测技术在上海天然气主干网杂散电流干扰控制中的应用

燃气管网的运行过程中,除流量、压力等对实时性要求高的参数外,还有管道的防腐层状态、管道腐蚀防护等参数,虽然这些参数对于实时性要求相对较低,但对于管道安全运行同样起到关键作用。尤其是管道的腐蚀防护相关参数,如:管地电位、管道防腐层漏点等,通过这些参数,我们可判别管道是否处于本质安全的状态。文章主要介绍了遥测技术在监控主干网部分管段的管地电位和地铁、高压输电线路、电气化铁路、磁悬浮等杂散电流干扰管段上的应用。     

北斗卫星微位移监测系统在油气管道地质灾害监测预警中的应用

油气管道铺设线路所经区域地形条件复杂,受到地质灾害的影响较大,为了避免地质灾害对管道造成破坏,提高油气管道运输的安全性,采用北斗卫星微位移监测模块对管道桩号为JG7410的滑坡地质灾害点进行实时监测。该点处管道穿坡而过,边坡完整性和植被覆盖遭到破坏,存在滑坡风险。我们将监测站布设于管道上方切坡处,基准站布设于距离监测站1km处,监测数据通过基准站进行校正、解算处理后,精度可达毫米级。此外,研究将获取的位移数据与降雨数据进行对比,结果表明:该滑坡体的沉降量与沉降速率主要受降雨因素影响,且沉降速率的加速与汛期有关。这说明北斗微位移监测模块在滑坡位移监测过程中应用前景很好,在很大程度上可以避免重大滑坡事故的发生,保证了油气管道完整性和安全性。     

Simulation-based deterioration patterns of water pipelines

Water pipelines deteriorate overtime due to several distressing factors. To keep water pipelines in good condition, municipalities need to use reliable and credible deterioration models and inspection plans to better manage their rehabilitation and maintenance. Thus, this paper presents the development of deterioration models and patterns of water pipelines. The deterioration models consider different water pipe sizes and materials as well as different surrounding environmental conditions which affect their deterioration rates. As a prerequisite to the development of such deterioration models, a condition assessment model for water pipelines was first developed. Questionnaires were distributed among experts to determine the weights of the factors affecting water pipeline conditions using the fuzzy analytic network process. Monte-Carlo simulation was used to account for the large uncertainties of the calculated weights in the development of the condition assessment model. The validation of the model, which was performed using historical data, yielded an average validity percentage of 93.59%. The developed models are expected to help municipalities and decision makers to accurately plan for future water pipelines maintenance and rehabilitation activities based on their different deterioration patterns. It takes into consideration both the uncertainties at the initial stage and those accumulated during the calculation process.     

基于RF-GOA-RVM的海底管道腐蚀速率预测

针对油气管道腐蚀预测模型参数确定困难及预测精度不高等问题,提出一种基于RF-GOA-RVM的腐蚀速率预测新方法。运用随机森林（RF）筛选海底管道腐蚀影响因素,确定腐蚀主要因素;用蝗虫算法（GOA）优化相关向量机（RVM）参数,预测管道腐蚀速率。仿真实验表明：与粒子群算法-相关向量机（PSO-RVM）和RVM相比,RF-GOA-RVM模型稳定性更好,预测精度更高,可为海底管道腐蚀失效预测提供决策依据。     

回填软土中管道上浮力测试及计算方法

管道已成为中国油气等流体输送的重要方式,在沿海软土地区中浅埋管道上浮事故屡有发生,严重威胁着能源生命线工程的安全。研发了一套回填软土中浅埋管道上浮力测试的装置及方法,针对常用输气管道开展了足尺模型试验,获得了不同扰动程度软土中的管-土相互作用及管道上浮力,揭示了回填软土中管道的上浮机理。基于多批次不同扰动程度软土中管道上浮力的测试结果,提出了与回填软土不排水剪强度相关的管道上浮力计算方法。     

杭州市埋地燃气钢管腐蚀与防护完整性管理

介绍管道完整性管理的工作内容和流程,结合杭州市燃气管道完整性管理现状和存在的问题,对埋地燃气钢质管道腐蚀与防护的完整性管理进行探讨。     

天然气输气管线的动静态混合模型研究

为保证长输管线末端用户的用气,必须了解管线的运行工况,沿程各点的压力、温度。分析了天然气长输管线系统的实际运行规律,建立了带压气站的长输管线静、动态混合数学模型,并对其进行求解,得出了长输管线的一般运行规律。     

Probabilistic characterisation of metal-loss corrosion growth on underground pipelines based on geometric Brownian motion process

This article describes a geometric Brownian motion process-based model to characterise the growth rate of the depth of corrosion defects on underground steel pipelines based on inspection data subjected to measurement uncertainties. To account for the uncertainties from different sources, the hierarchical Bayesian method is used to formulate the growth model, and the Markov Chain Monte Carlo simulation techniques are used to numerically evaluate the probabilistic characteristics of the model parameters. The growth model considers the bias and random scattering error associated with the in-line inspection (ILI) tool as well as the correlations between the random scattering errors associated with different ILI tools. The application of the growth model is illustrated through an example involving real ILI data collected from an in-service pipeline in Canada. The results indicate that the model in general can predict the growth of corrosion defects reasonably well. The proposed model can be used to facilitate the development and application of reliability-based pipeline corrosion management.     

交流电流衰减法（PCM）在埋地钢质管道防腐检测中的应斥

随着城市的建设和发展,埋地管线的种类和数量迅速增多,相应地也出现了涉及地下管线安全运行的各种腐蚀问题。因此开展埋地管道防腐层的非开挖检测非常必要。本文简要介绍了埋地管道非开挖检测常用的方法,然后具体围绕交流电流衰减法（PCM）的工作原理、检测前的准备展开讨论,并且以北京某地区的天然气埋地管道非开挖检测工作为例,介绍一则应用交流电流衰减法（PCM）进行埋地管道防腐层检测的工程实例,根据检测数据和管中电流随测量距离的变化曲线进行分析,确定了破损点的位置,并进行了开挖验证,将评价结果和开挖检测结果做了比较。之后指出了应用该法的局限性并提出相关建议。最后对未来的检测方法进行了展望。     

电瓷产品落铁缺陷原因分析及其对策

落铁缺陷严重影响电瓷产品的外观质量,分析认为落铁缺陷是煤气管道和高压风管道内的铁屑和积尘引起的。采取增加煤气过滤器,更换煤气管道,定期清理管道等措施后,取得了较好的效果,使落铁瓷件控制在1%以下。     

Multi-objective maintenance strategy for in-service corroding pipelines using genetic algorithms

Abstract

The multi-objective optimisation technique utilising genetic algorithms is employed to develop the optimal maintenance strategy for corroding oil and gas pipelines. The objective functions of the optimisation are the maximum annual conditional probabilities of small leak and burst, respectively, of all the pipe joints included in the pipeline segment over a predefined time horizon, and the total present-value cost of corrosion repair. The allowable annual probabilities of small leak and burst, and the annual repair budget are treated as constraints in the optimisation. The proposed optimal maintenance strategy is illustrated using a natural gas pipeline segment consisting of 90 corroding pipe joints. The analysis results indicate that a diverse set of solutions are included in the obtained Pareto front, which allow the decision-maker to select the maintenance plan achieving the desired tradeoff between the reliability and cost. The approach presented in this study can be incorporated in the practical optimal maintenance planning of corroding pipelines subjected to safety and resource constraints.     

考虑随机腐蚀作用的埋地管线地震反应分析

利用齐次马尔可夫过程模拟埋地管线腐蚀的发生,并利用线性腐蚀模型模拟埋地管线腐蚀的发展,将线性腐蚀模型中腐蚀速率考虑为确定性参数,推导给出了管线面积腐蚀率随服役时间变化的概率密度函数,并获得了管线截面面积随服役时间变化的均值和方差。在此基础上,根据弹性地基梁模型,将管线周围土体位移正交展开为余弦级数的形式,获得了地震作用下腐蚀管线位移反应和应力反应的解析表达式。对腐蚀管线地震反应进行线性展开,采用随机摄动理论推导给出了腐蚀管线在地震激励下位移和应力反应的均值和标准差。利用上述分析模型对一根200 m长的埋地管线进行了实例分析,结果表明建议模型可以反映管线面积随服役时间的变化规律,并能反映腐蚀管线在地震作用下位移反应和应力反应的基本概率特征。