Some of Australia’s offshore gas and oil platforms are near the end of their operational life. Decommissioning must proceed safely, and achieve good outcomes for the environment, community, and the economy. Different decommissioning approaches require careful consideration of scientific evidence, and technical and financial feasibility assessments. With 12,000 platforms worldwide, and many aging, this is a global issue.
The two main options for decommissioning are: to remove the structures for onshore disposal; or, to leave them in place, mostly intact, as artificial reefs or for other purposes. Full platform-removal is the default regulatory position of the Australian government; however, the Environment Protection (Sea Dumping) Act 1981 includes the possibility of authorised ‘abandonment in place.’
Full scientific evidence to support best-practice decommissioning under different scenarios is currently not available; therefore, some decisions must be made, and activities undertaken, without a full understanding of the consequences.
Worldwide, researchers work on the various aspects of decommissioning science, but a thorough global assessment of the state of knowledge, the information gaps, and the research needed to address these shortfalls, has been largely overlooked. This project addressed these problems.
Approach and findings
Offshore platform decommissioning concerns various stakeholder groups, and the scientific and other issues span many disciplines. This inherent complexity favoured a transdisciplinary ‘horizon-scanning’ research approach – the surveying of existing science, relevant reports, general literature and various media.
Concurrently, 35 experts from relevant fields, and from all geographic regions were consulted. Each expert was asked to list their most important questions regarding decommissioning that were, so far, inadequately addressed, as well as associated research topics.
Overall, the experts submitted 247 questions which were categorised according to similarity, into 5 disciplinary areas, 15 topics, and 38 sub-topics.
The project and experts consensually agreed on the following top ten research priorities for informing, planning and implementing best-outcome platform decommissioning.
- Assessment of contaminant impacts and acceptable limits, to reduce ecological harm.
- Risk and acceptability threshold definitions within policy and governance.
- Liability issue characterisation, including ongoing costs and responsibilities.
- Quantification of impacts to ecosystem services.
- Quantification of ecological connectivity.
- Assessments of marine life productivity.
- Determination of infrastructure reuse feasibilities.
- Identification of stakeholder views and values.
- Quantification of greenhouse gas emissions.
- Development of a transdisciplinary decommissioning decision-making process.
The list of research priorities compiled by the project is ‘an authoritative consensus plan’ and ‘roadmap’ for the essential science needed to support future decommissioning activities and achieve good outcomes. Significant investment will be needed to undertake this research.
Research results will better inform policy development and governance frameworks as well as provide industry and stakeholders with greater clarity around all aspects of offshore decommissioning. This will also be transferable to other offshore renewable energy infrastructure, in particular, wind turbines.
Given that all the identified research priorities have common application to all geographic regions, it would be advantageous for future research collaborations to share costs and roles. Cross-disciplinary teamwork will be ideal as priorities are also global, complex, cross-sector, interdependent, and transdisciplinary.
- Research pathway identified to support offshore energy infrastructure decommissioning.
- Innovative decision-making developed and utilised to prioritise current knowledge gaps and future research needs.
Blue Carbon Lab
Offshore decommissioning organisations
National Offshore Petroleum Safety and Environmental Management Authority
Oil and gas producers
Department of Climate Change, Energy, the Environment and Water
Marine research community
Journal article – Project 1.19
Offshore decommissioning horizon scan: research priorities to support decision-making activities for oil and gas infrastructure
Watson SM, McLean DL, Balcom BJ, Birchenough SNR, Brand AM, Camprasse ECM, Claisse JT, Coolen JWP, Cresswell T, Fokkema B, Gourvenec S, Henry L, Hewitt CL, Love MS, MacIntosh AE, Marnane M, McKinley E, Micallef S, Morgan D, Nicolette J, Ounanian K, Patterson J, Seath K, Selman AGL, Suthers IM, Todd VLG, Tung A, Macreadie P (2023). Offshore decommissioning horizon scan: Research priorities to support decision-making activities for oil and gas infrastructure. Science of The Total Environment. Vol 878.
Fact sheet – Project 1.19
Project 1.19 Information sheet
NESP Marine and Coastal Hub (2021). Scoping Study: Horizon scan of key science questions in the decommissioning of offshore oil and gas infrastructure. Project 1.19 Information sheet. Reef and Rainforest Research Centre, Cairns, Queensland.