As pipelines near the end of their operational lifecycle, decisions regarding how they will be abandoned are made. Operators make these decisions based on various considerations, of which include, but not limited to: contractual obligations, current and proposed land uses, cost, risks to human health and safety, ecology and environment, and valued/economic resources. Consultation with land owners and land managers must also play a central role in the decision-making process. Ultimately, decisions made by operators must be approved by the National Energy Board (NEB) (for interprovincial and international pipeline systems) or by provincial regulatory agencies (for intra-provincial pipeline systems).
A key decision that operators must make is where to remove abandoned pipeline from the ground and where to leave pipeline in the ground and abandon it in-place. In some cases, contractual obligations or proposed future land use will dictate the requirement for pipeline removal. However, in many cases this decision will be made based on weighing the relative risks associated with removal versus abandonment in-place, along with the feasibility and desirability of risk management measures required to mitigate risks associated with each. As stated in Canadian Energy Pipeline Association (CEPA 2007): A risk-based comprehensive site-specific assessment is needed to validate the chosen abandonment strategy for specific pipelines. In some cases, a combination of removal and abandonment in-place will be selected.
This guidance sets out a framework (referred to herein as the “Framework”) whereby operators can evaluate (on a site-specific basis) risks associated with the physical and technical hazards related to abandoning pipelines in-place and determine the need for risk management measures to mitigate these risks. Operators can then compare risks and the feasibility and desirability of appropriate risk management measures for abandonment in-place to those associated with pipeline removal to support the selection of either of these options. It should be noted that use of the Framework by persons or organizations beyond pipeline operators could be inhibited unless detailed background information is provided to understand the setting and hazards at any particular segment of a pipeline.
In addition, this guidance does not provide a framework whereby operators can evaluate risks associated with pipeline removal, although as discussed above these must be evaluated and compared to those associated with abandonment in-place prior to final selection of either option. As stated in Pipeline Abandonment Steering Committee (PASC 1996): Once the principal technique has been chosen, the owner/operator should assess on a site-specific basis whether an alternate approach should be followed for selected segments of line.
Consultation with land owners, land managers, and other stakeholders has also been addressed by this guidance, without specifying details. The primary objective of the Framework is to provide a consistent, transparent, and scientific basis by which decisions pertaining to the selection of abandonment options (and associated risk management measures to address physical and technical hazards) can be made and communicated.