SEMINAR: On-bottom Stability of Offshore Pipelines

Conventional pipeline design assesses hydrodynamic stability of offshore pipelines without taking into account sediment transport occurring around the pipeline (e.g. DNV-RP-F109). There are growing concerns that such a design approach is flawed (Palmer 1996). It is evident that the seabed that supports the pipeline will become mobile well before the extreme design condition is reached during a storm event. Sediment transport (local scour) may lead to pipeline natural selfburial. Pipeline embedment gained through burial process has significant effect on pipeline stability due to the changes in lateral soil resistance and hydrodynamic loading. Field observations have shown that certain levels of embedment occurred to existing pipelines laid on the North West Shelf (NWS) of Western Australia It is speculated that the ignorance of sediment transport processes leads to increased costs associated with pipeline stabilization. There are insufficient knowledge and analytical tools available to address this problem. With a number of major projects in Australia being planned, the cost benefits of a research project on this issue will be significant.

This talk will present some of the relevant research work carried out at the University of Western Australia to the topic, especially a recent Joint Industrial Project (JIP) - STABLEpipe.