RISK MANAGEMENT FOR LATERAL CHANNEL MOVEMENT AT PIPELINE WATER CROSSINGS

摘要

Pembina Pipeline Corporation (Pembina) owns and operates close to 10,000 km of crude, natural gas liquids (NGL), and natural gas pipelines across North America, with the majority of assets in western Alberta and eastern British Columbia. The Pembina pipeline network includes over 1,600 river and stream crossings, most of which are subject to varying degrees of vertical and/or lateral erosion. 1,260 crossings were in Alberta at the onset of the study. Identifying potential lateral erosion hazards is a critical component of geohazard management program for pipeline integrity. In 2012, Pembina initiated a three-phase program to proactively address lateral-stability issues at river and stream crossings in Alberta: phase one identified and short-listed crossings that have potential lateral channel-shifting problems; phase two assessed which short-listed crossings have insufficient cover depth to accommodate the potential channel-shifting activities and ranked these crossings as high risk of exposure; and phase three will develop plans for repair and/or replacement of the high-risk crossings. Through this program, Pembina explores the significance of lateral erosion and encroachment at pipeline water crossings of various vintages, with regards to pipeline integrity. This paper provides discussion as to how crossing geohazard risks are identified, with particular emphasis on stream bank erosion, and how this fits into Pembina's overall risk management program. As well, selected case studies are provided.