Executive Summary

As the pipeline infrastructure grows and ages across Canada, abandonment and/or discontinuation of pipelines may increase as well. The process of abandonment/discontinuation needs to be properly handled and executed in order to minimize or eliminate any potential related issues. Communities’ stakeholders have raised concerns about the safety of the pipeline abandonment process and about the related long term effects, especially in agricultural areas. For pipelines abandoned in place, the issue of cleanliness is a crucial one and of major concern from environmental and economic standpoints. An abandoned pipeline will inevitably corrode and could lose structural integrity posing the risk of releasing any residual contaminants into the surrounding soil and groundwater. Therefore, assessing the effectiveness of cleaning technologies for pipelines and investigating residual contaminants and methods to detect them are crucial topics that need to be properly addressed.

This study covers the requirements of PTAC Pipeline Abandonment Research Steering Committee (PARSC): PARSC 004 – Cleaning Methods for Abandoned Pipeline and PARSC 005 – Standard Pipeline Products List and Detection of Residual Contamination in Abandoned Pipelines. The two main areas that this study covers are 1) the effectiveness of cleaning methods (mechanical and chemical methods) for pipeline abandonment; and 2) potential residual contaminants and methods to detect them. In addition, the study reviews federal and provincial regulations and standards that address the subject of abandonment/deactivation, and presents some of the current industry abandonment guidelines and programs.

The scope of this report is focused on oil and gas transmission pipelines in Canada. The main research methodologies were direct engagements with stakeholders and literature searches. The latter includes industry reports, conference and journal technical papers, government agencies publications, and other open sources.

From the engagement surveys, it was found that most of the pipeline operators do not have detailed guidelines for abandonment with the exception of few companies that are currently undergoing major abandonment/decommissioning projects. This is due to the fact that, to date, pipeline abandonment has not been commonly occurring in transmission pipeline companies.

Mechanical cleaning suppliers have their own recommendation or guidelines for pipeline abandonment and these are centered on proper pig selection. Upon request, suppliers readily provide pig selection criteria to operating companies interested in cleaning a pipe for the purposes of abandonment. The same is also true for chemical suppliers who would recommend different chemical cleaning products based on the history of the pipeline, commodity, and purpose of cleaning, among others. Moreover, the interview with the provincial and federal regulators confirmed that very few regulations exist regarding cleaning procedures for abandonment and no criteria exist on the acceptable levels of residual contaminants. The CSA standard Z662 was found to be used by different provinces and companies as minimum requirements that must be met.

In crude oil pipelines, the main contaminants are sludge deposits. Sludge deposits vary in composition from one line to another. In general, O is the most present element (37.1- 54.9 %) followed by Si (14.4 – 31.3 %) and then Fe (3.4 – 27.34 %). Other elements such as C and S also may exist, but to a lesser percentage. In gas pipelines, the main contaminants are black powder, NORMs, hydrocarbons, and PCBs. Checking the level of residues left in the pipeline after cleaning is essential to verify the effectiveness of the cleaning program. The identification of test methods for residual contaminant has provided direction for field testing that could be performed as well as a basis for establishing a list of contaminants that could be regulated. The existence of commercial field testing instruments will render on-site sampling and testing more feasible and cost effective.

Given that pipeline abandonment is a complex process with multiple factors to consider; it would be advisable to develop recommended guidelines for cleaning abandoned pipelines. The recommended guidelines, which can eventually be transitioned into a standard, would be extremely beneficial to the industry and pipeline operators, as well as the regulators and other stakeholders (e.g. land owners), as it will aim to standardize the process of pipeline abandonment. Meanwhile, more recommendations are discussed at the end of this study.


Pipeline abandonment refers to the permanent removal from service of a pipeline. Depending on a number of factors, sections of pipeline may be abandoned in place or removed.

CEPA, the National Energy Board (NEB), the Alberta Energy and Utilities Board (AEUB) and the Canadian Association of Petroleum Producers (CAPP) have collaborated on technical and environmental issues associated with pipeline abandonment, which issues were discussed in the documents referenced below. In 1996, the NEB published a review document titled “Pipeline Abandonment – A Discussion Paper on Technical and Environmental Issues”. In 2007, CEPA published a report titled “Pipeline Abandonment Assumptions” which discussed technical and environmental considerations for development of pipeline abandonment strategies. A comprehensive review was undertaken by the NEB as part of the Land Matters Consultation Initiative (LMCI) which involved four discussion papers on the different topic areas, 45 meetings and workshops in 25 communities across Canada, and written submissions from 13 parties. The final LMCI report, published in 2009 recommended that knowledge gaps on the physical issues of pipeline abandonment be addressed. Thus, Det Norske Veritas (DNV) was commissioned to conduct a literature review regarding the current understanding worldwide with respect to the physical and technical issues associated with onshore pipeline abandonment and use the results of the literature review to critically analyze and identify gaps in current knowledge, and make recommendations as to potential future research projects that could help to fill those gaps. DNV published this Scoping Study in November 2010.

CEPA and PTAC have established the Pipeline Abandonment Research Steering Committee (PARSC) as a framework for collaboration to guide and direct innovation and applied research, technology development, demonstration, and deployment in order to address knowledge gaps summarized in the DNV Scoping Study. Research findings from the PARSC projects will be shared on a broad scale throughout the pipeline industry, the oil and gas industry, as well as with regulators, government agencies, and other stakeholders.

Final Report

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