Environmental considerations for pipeline abandonment

摘要

Since the 1920s, over 400,000 km of petroleum pipelines have been installed in Alberta. Pipeline abandonment isnan increasingly relevant issue as the pipeline network ages. The full or partial abandonment of pipeline systems isnnecessitated by factors such as wind or water erosion issues, pipeline integrity issues, changes in source supply andncustomer demand, urban development encroachment and regulatory requirements.nPipeline abandonment-in-place is generally the preferred option based on the technical condition and environmentalnsustainability of the pipeline; however, in some cases pipeline removal or partial removal cannot be avoided. In all cases,nthe planning process for abandonment includes technical evaluation, risk assessment, environmental assessment,nlandowner consultation, and/or evaluation of future land use. Abandonment plans must also include environmentalnprotection measures to be implemented during the removal of any pipeline segment and consideration of the postabandonmentnimplications of any pipeline left in place. These measures include topsoil conservation, erosion/sedimentncontrol and reclamation.nThis article discusses environmental protection measures for pipeline abandonment, using issues faced duringnabandonment of one of the oldest natural gas pipelines in Alberta as a case study. Challenges faced during this projectnincluded gathering of appropriate historical information including leak history and maintenance records, removal of allnabove-ground facilities, accommodations for future land use plans including road development, and measures taken tonminimise the risk of the abandoned pipeline becoming a water conduit. In addition, the article will discuss the extensivenplanning and construction effort required to undertake pipeline abandonment at several fish-bearing watercoursencrossings, where pipeline exposures during high-water events necessitated pipeline removal. A primary objective in thenplanning and the removal of the abandoned pipeline was minimal disturbance of the land.