Reliability-based Assessment of Interacting Integrity Threats to Energy Pipelines

高压大直径钢输送管道被广泛认为是长距离输送大量油气的最安全、最经济的方式。输油管行业对加拿大经济至关重要：2015年，该行业为加拿大国内生产总值（gdp）贡献了115亿美元；2014年，加拿大价值810亿美元的原油和天然气出口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内向加拿大管道项目投资总额为500亿美元。加拿大庞大的石油和天然气输送管网的安全至关重要，具有深远的社会政治影响。申请人研究项目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才，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。当前提案的目标是为受到相互作用完整性威胁的现有管道开发基于可靠性的适用性（FFS）评估方法，这些威胁的定义是对管道结构完整性的不利影响相互关联和相互作用的两种或多种威胁。具体而言，提出的研究旨在1)了解管道在凹痕腐蚀威胁下的失效机制；b) dent-crack;c) crack-in-corrosion;D)腐蚀和管道内部压力以外的外部载荷；2)为上述相互作用威胁下的管道开发准确、实用的适用性评估方法和模型；3)开发方法来评估相互作用威胁下管道的系统可靠性；4)校准负载和阻力因素，以实现管道在相互作用威胁下的可靠性一致的FFS评估。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。拟议的研究项目将培养7名博士生、2名MESc学生和2名本科生，并与加拿大主要管道运营商密切合作。该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.