Reliability-based Assessment of Interacting Integrity Threats to Energy Pipelines

高压大口径钢质管道被广泛认为是长距离输送大量石油和天然气的最安全、最经济的方式。输送管道行业对加拿大经济至关重要：2015年，它为加拿大国内生产总值贡献了115亿美元；2014年加拿大810亿美元的原油和天然气出口中，大部分是通过管道运输的，加拿大能源管道协会的成员提议在未来五年向加拿大管道项目投资总计500亿美元。加拿大庞大的石油和天然气输送管道网络的安全至关重要，并具有深远的社会政治影响。申请者研究计划的长期目标是开发新的知识、方法、模型、决策支持系统和高素质的人员，以确保加拿大石油和天然气管道网络的安全性、弹性和可持续性。当前建议的目标是为受到相互作用的完整性威胁的现有管道开发基于可靠性的服务适宜度(FFS)评估方法，该威胁被定义为对管道结构完整性的不利影响相互关联和相互作用的两个或两个以上威胁。具体而言，这项研究的目的是：1)了解管道在a)凹陷腐蚀；b)凹陷裂纹；c)腐蚀裂纹；d)腐蚀和除管道内压以外的外部载荷下的失效机理；2)建立准确、实用的管道在上述相互作用威胁下的服役适宜性评估方法和模型；3)开发评估管道在相互作用威胁下的系统可靠性的方法；以及4)校准载荷和阻力系数，以实现关于相互作用威胁的管道可靠性的FFS评估。这项研究将主要基于理论建模和广泛的数值研究，包括高保真有限元分析。拟议的研究计划将培训7名博士生、2名MESc学生和2名本科生，并涉及与加拿大主要管道运营商的密切合作。这项研究将为加拿大管道运营商提供急需的工具，以有效应对相互作用的完整性威胁，从而保护加拿大人享有的生命、环境和高生活水平。

High-pressure large-diameter steel transmission pipelines are widely recognized as the safest and most economical means to transport large quantities of oil and gas over long distances. The transmission pipeline industry is vital to the Canadian economy: it contributed $11.5 billion to Canada's gross domestic product in 2015; most of the $81 billion Canadian crude oil and natural gas exports in 2014 was transported by pipelines, and members of the Canadian Energy Pipeline Association are proposing to invest a total of $50 billion in Canadian pipeline projects over the next five years. The safety of the vast oil and gas transmission pipeline networks in Canada is of critical importance and has profound socio-political implications. The long-term objective of the applicant's research program is to develop new knowledge, methods, models, decision-support systems and highly qualified personnel that will ensure the safety, resilience and sustainability of the Canadian oil and gas pipeline networks. The objective of the current proposal is to develop reliability-based fitness-for-service (FFS) assessment methodologies for existing pipelines subjected to interacting integrity threats, defined as two or more threats whose adverse effects on the structural integrity of pipelines are interrelated and interacting. Specifically, the proposed research is aimed at 1) understanding the failure mechanisms of pipelines under the threats of a) dent-corrosion; b) dent-crack; c) crack-in-corrosion; d) corrosion and external loads other than the pipeline internal pressure; 2) develop accurate, practical fitness-for-service assessment methodologies and models for pipelines under the above-mentioned interacting threats; 3) develop methodologies to evaluate the system reliability of pipelines under interacting threats, and 4) calibrate load and resistance factors to achieve reliability-consistent FFS assessment of pipelines with respect to interacting threats. The research will be based primarily on theoretical modeling and extensive numerical investigations involving high-fidelity finite element analyses. The proposed research program will train seven PhD students, two MESc students and two undergraduate students, and involve close collaborations with major Canadian pipeline operators. The research will provide much-needed tools for Canadian pipeline operators to deal effectively with interacting integrity threats, thus protecting lives, environment and high standard of living enjoyed by Canadians.