Pipeline Ice Risk Assessment and Mitigation
Without an environmentally appropriate transportation solution, resources remain stranded. Advancement of safe, cost-effective and reliable pipeline infrastructure is another essential for field developments in ice environments. Pipeline Ice Risk Assessment and Mitigation (PIRAM) was a Joint Industry Program (JIP) led by C-CORE from 2007 to 2009. With a budget approaching $5 million, the program was funded by C-CORE, seven oil and gas companies and the Atlantic Innovation Fund (AIF) of Atlantic Canada Opportunities Agency (ACOA). The work was conducted in partnership with a number of research institutes, companies and consultants.
PIRAM developed methodologies to determine contact frequency and loads from gouging ice keels, established pipeline mechanical behavior in response to ice keel load events, and developed engineering models and procedures that could be implemented into industry best practices for mitigation of risk and protection of pipeline infrastructure from ice keel loading. PIRAM improved and expanded the first pipeline burial guidelines proposed by C-CORE in 2005. It also complements the work of other recent JIPs including DnV: IcePipe (Davies 2011) and tank tests and medium-scale field tests (Sancio 2011) performed at Canada's National Research Council Ice Research facility in St. John's, NL. The initial region of focus was the Beaufort Sea; however, the PIRAM models are applicable or adaptable to many ice-prone regions where export pipelines may eventually be required.
PIRAM's contact frequency model established the interaction frequency between ice features and the seabed or subsea infrastructure. The ice load model calculated the ice keel resistance for those interaction events. The pipeline protection model studied the interaction of ice features with pipeline systems. The models were integrated within a graphical user interface (GIS) framework to perform pipeline routing and burial analysis for protection against ice keel gouging, and a probabilistic pipeline burial analysis was incorporated that accounts for the influence of sub-gouge soil displacements. PIRAM significantly advanced pipeline routing and burial optimization approaches, resulting in documented substantial burial cost reductions. The program also identified the importance of multiple fingered keels. The ice keel tests completed were a first of their kind, complementing work that included the investigation of the potential of ice limits – shape, resistance and kinematics.