This paper presents the methodology for developing and applying a risk based inspection (RBI) strategy for 14 steel jacket structures located in Bass Strait, Australia. The platforms range in age from 10 to 30 years and are situated in water depths between 46 and 96 metres. The RBI methodology was developed to improve the prediction of the structures' condition and provide a consistent basis for continued improvement in the future. This methodology produces targeted inspection work-scopes for each platform that, coupled with the implementation of appropriate inspection techniques, ensure that the integrity of the platforms can be managed with greater confidence and at lower cost.
For more than 30 years Esso Australia Ltd., with 50:50 joint venturer BHP, has been producing oil and gas from Bass Strait, an area off the South East Coast of Australia with one of the harshest environments in the world. Since early 1969 Bass Strait has been Australia's premier oil and gas production area, transforming Australia's oil supply situation from one of almost complete dependency on imports to one of substantial self-sufficiency. With 14 steel jacket structures, the underwater inspection, repair and maintenance activities have consumed a significant proportion of the overall operating budget. In the mid 1990's Esso decided to improve the effectiveness and efficiency of inspection by implementing a risk-based approach. The problem faced was to develop a practical risk-based inspection planning strategy capable of maintaining effective safeguards against structural deterioration at a minimal cost. In 1997 Esso contracted QCL lntemational to assist in developing and tailoring such a strategy to the Bass Strait fields and to apply this risk-based approach to the jacket structures.
