The objective of this study is to lead to a greater understanding of the potential causes or scenarios that would lead to the exposure of abandoned buried pipelines.
The study will include four components all related to developing a greater understanding of the potential for exposure of abandoned pipelines.
- Analysis of exposure data of TransCanada, Enbridge, Kinder Morgan and possibly other pipeline operators in order to mine the data and identify typical scenarios that have led to exposure.
This workflow will analyse exposure databases from operating pipelines to compile frequency statistics and infer from this analysis the most likely scenarios and or geotechnical hazards that have led to pipeline exposure.
- A scoping study to estimate the longevity in an abandonment situation of buoyancy control measures used to manage Canadian onshore pipelines, and identify possible mitigation measures.
The potential loss of buoyancy control measures in situations where buoyancy control is required may lead to pipeline exposure. Therefore it is important to understand the expected longevity of typical buoyancy control measures and circumstances that could lead to their degradation and failure. This component of the study will include a literature review to identify information that is already available, a conceptual analysis of degradation and failure modes of buoyancy control measures, an estimate of longevity with a discussion of factor that may affect the outcome, and recommendations for future studies which may include laboratory work, if necessary, to generate missing information about materials longevity and or degradation processes.
- A scoping study about abandonment under water bodies and sensitive ecological areas such as wetlands. The study would also investigate low impact pipe removal methods.
Existing approaches to abandoning pipelines under water bodies may include abandonment in place, cutting and capping the pipe at each side of the water body, and, in some cases, removal of all or some of the pipe in anticipation of stream bed scour or lateral river channel migration. Filling the pipe with cement could be used in anticipation of the loss of buoyancy control. This scoping study will review, summarize and provide a conceptual analysis of available options.
Removal of the underwater section of the pipeline could result in significant disturbance to the water body. However, potential techniques that could remove sections of buried pipeline while causing little to no surface disturbance would be very attractive, particularly for watercourse crossings. This component of the study will propose a scope for a future engineering study to investigate and comment on the feasibility of potential techniques to remove sections of buried pipeline without causing significant surface disturbance in the context of pipelines buried under water bodies or sensitive ecological areas.
- Scoping of a field study to take measurements of frost heave exposure potential in abandoned pipelines.
PARSC published in 2014 the report entitled “Frost Heave Effects on Pipeline Exposure Rates”. Section 7.2.1 of this report described a suggested field research strategy. It was proposed to establish field monitoring stations over abandoned pipelines across Canada to monitor depth of cover and soil temperature over a three-year period. This component of the study will develop a scope for the proposed field research strategy.