Woodside Energy Limited
Woodside Browse Project: Cyclone Moorings, Site Selection and Engineering Study
ICON Engineering Pty Ltd, in collaboration with Beagle Bay Marine Pty Ltd, carried out the Browse Cyclone Mooring Study for Woodside Energy Limited. The initial proposal was titled “Site Selection and Engineering of Cyclone Moorings”.
It was intended to cater for a range of dredgers, barges, and associated support vessels that would be utilized for marine civil works at James Price Point, a significant component of Woodside’s planned Browse LNG Project.
An image of 2008's Cyclone Billy
James Price Point is in the western Kimberley, the most cyclone-prone region in the southern hemisphere. It is completely exposed, and a tight schedule calls for at least part of the marine spread to remain on site throughout the cyclone season.
Comprehensive Cyclone Risk Analysis
The aims and emphasis of the Study changed somewhat during the negotiation phase, and indeed throughout the implementation of the project. Site selection remained the pivotal element, to provide for the safe and rapid demobilisation and remobilisation of vessels and crews. With respect to the engineering, detailed mooring design has been replaced by a comparative mooring load study, undertaken by DHI Water and Environment Pty Ltd. Much time has also been spent on assessing potential personnel shelters, carrying out a comprehensive risk analysis, investigating the complex approvals process, and determining how best to work with and benefit the neighbouring Indigenous communities.
Three potential cyclone mooring sites have been short-listed: Beagle Bay just north of James Price Point; and Powerful Island and Boonook Bay further north in the Buccaneer Archipelago. Roebuck Bay is also a potential site, but only for vessels less than 35 m in length. Beagle Bay is the closest site and has the advantage of existing infrastructure, including an airstrip and road access. However, it is the least sheltered location. Powerful Island is better protected, and Boonook Bay better still. However, these sites are perhaps too far from James Price Point for slow moving vessels such as tug / barge combinations. The mooring load study indicates that while Beagle Bay is less than ideal, this site could still be viable if appropriately designed moorings are installed. Faster moving vessels would potentially be safer in the Buccaneer Archipelago.
Severe Risks Were Identified
A Hazard Identification workshop was conducted after the risk analysis had been drafted. The workshop covered cyclone contingency procedures, vessel routes, cyclone tracking and intensity, anecdotal examples of cyclone survival, specific vessel vulnerability, mooring types, personnel evacuation, vessel manning, weather forecasting, and mooring procedures. A number of severe risks were identified, many associated with barging materials from Dampier to James Price Point. Risk reduction recommendations have been made. Partly as a result of this work Woodside has deemed Dampier unsuitable as a supply port.
Tracking the path of a Browse Basin cyclone
Discussions with the Western Australian Department of Transport (DOT) exposed a number of shortcomings in their cyclone mooring allocation policy. The ruling allocating one mooring to one specified vessel is inappropriate for a large scale marine operation. More troubling is the written policy eliminating native title claim areas from DOT jurisdiction. The Department of Regional Development and Lands has since exempted the DOT from their own ruling. However, the needs and rights of the Traditional Owners have not been addressed. Nor have their potential claims under the Aboriginal Heritage Management Plan. It is likely that the Department of State Development will have to be called upon to resolve these issues.
Overall, it has been demonstrated that there are solutions to the cyclone mooring problem. Potential sites have been identified. Ultimately, the safety of vessels and crews will depend upon good cyclone mooring design, and the strict implementation of a carefully considered cyclone contingency plan.