Four North American pipeline operators and a pipeline inspection company have been working together on a research project assessing the feasibility of using an electromagnetic non-contacting strain measurement tool capable of being deployed during ILI inspection to measure axial strain in pipelines. The axial strain sensor is the TSC StressProbe. It is an electromagnetic technique which makes use of the fact that when a steel structure is loaded, its electromagnetic properties change. Monitoring the changes in magnetic properties allows one to measure changes in strain. The use of in-line inspection high resolution inertial survey tool data in the determination of bending strain in operating pipelines is well developed and understood. The missing component in determining the total strain in the pipeline is to understand the component of axial strain that the pipeline is experiencing without the need to expose the pipeline for the installation of surficial pipe monitoring (primarily strain gauges) or destructive testing (such as cut-outs). Many current methods of stress/strain measurement including the installation of strain gauges only allows for the determination of change in strain going forward from the date of install; whereas, the StressProbe responds to total strain at the time of inspection. This paper will present the technology implementation, inspection feasibility and discuss preliminary results from case studies in determining the ability of the in-line inspection axial strain measurement to correlate with known changes in strain in pipelines being influenced by ground movements.

Pipeline watercourse crossings are designed according to the best available industry/technical standards at the time of construction. Older pipeline systems were typically installed without the benefit of modern hydrotechnical engineering practices with little or no allowance for ongoing fluvial processes. The level of protection at specific crossings can deteriorate such that a relatively small flood (i.e. 1:10 year) can pose a significant integrity threat. The hazards associated with maintaining an existing crossing may not be acceptable for the continued safe operation of a pipeline; therefore, a pipe replacement may be required. The designing, planning, permitting, funding, contracting and construction of any pipe replacement option can require considerable time to implement. In most watercourses in Canada and the United States this means that the pipeline at risk, but not in an emergency situation, will likely go through at least one spring freshet and/or other seasonal peak flow event(s) prior to implementation of the pipe replacement project. Four examples of short term risk control measures are discussed for river crossings in and around central and northern British Columbia, Canada.

Ground movements such as landslides, subsidence, and settlement can pose serious threats to the integrity of pipelines. The consequences of a ground movement event can vary greatly. Certain types of ground movements are slow-moving and can be monitored and mitigated before a catastrophic failure. Other forms of ground movements can be difficult to predict. The most effective approach could be hazard avoidance, proactive means to reduce strain demand on pipelines, and/or building sufficiently robust pipeline segments that have a high tolerance to the strain demand. This paper provides an overview of a Joint Industry Project (JIP) aimed at developing a best-practice document on managing ground movement hazards. The hazards being focused on are landslides and ground settlement, including mine subsidence. This document attempts to address nearly all major elements necessary for the management of such hazards. The most unique feature of the JIP is that the scope included the hazard management approach often practiced by geotechnical engineers and the fitness-for-service assessment of pipelines often performed by pipeline integrity engineers. The document developed in the JIP provides a technical background of various existing and emerging technologies. The recommendations were developed based on a solid fundamental understanding of these technologies and a wide array of actual field experiences. In addition to the various elements involved in the management of ground movement hazards, the JIP addresses some common misconceptions about the adequacy of codes and standards, including: • The adequacy of design requirements in ASME B31.4 and B31.8 with respect to ground movement hazards, • The adequacy of linepipe standards such as API 5L and welding standards such as API 1104 for producing strain-resistant pipelines, • The proper interpretation of the longitudinal strain design limit of 2% strain in ASME B31.4 and B31.8, and • The effectiveness of hydrostatic testing in “weeding out” low strain tolerance girth welds.

Inline Inspection Internal Measurement Unit (ILI IMU) data analysis is a well understood but often under-utilized technology for detecting, defining, assessing and monitoring soil to pipeline interactions. The technology has been successfully used to detect landslide interactions since 1996 [1]. Operators can be provided with a vendor analysis (initial bending strain or run to run movements) and/or processed raw data for either internal or third-party raw data Analysis [2]. Vendor Analysis typically identifies major soil/pipeline interactions but primarily reports dig related settlements [3] and static construction related features. Raw data analysis is typically used to define interactions and provide detailed pipe shapes and deformations within targeted pipeline segments. An approach for determining ILI IMU analysis/data requirements for individual ILI run segments for any size of pipeline system is presented. Guidelines for analysis are provided for Operators to optimize efforts based on the hazards encountered in individual pipelines or pipeline systems. The process includes feature screening, integrity/geotechnical specialist review and risk control/mitigation measures, if required. To facilitate the feature screening process, a classification system for ILI IMU features is presented based on their type, activity and source modified from the system presented in [3].