Decommissioning offshore oil and gas infrastructure: liability or opportunity?
In the waters around Australia there are dozens of oil and gas platforms and an estimated 3,500 kilometres of pipeline that are now coming to the end of their lifespan.
Decisions taken in the coming years will determine whether this infrastructure becomes an environmental liability or an opportunity for innovation.
There are a range of decommissioning options under consideration. At some sites, structures may be best left in place. At others, there is potential for removal, relocation, or repurposing – for renewables, carbon capture and storage, or even aquaculture.
Each option brings a different set of risks that need to be assessed. A 2018 review by the Department of Industry, Science, Energy and Resources stated that decommissioning activities “must be done in a safe and environmentally responsible way.”
Solutions that minimise risk
Using a range of tools and capabilities, CSIRO can help identify methods of decommissioning that minimise risk to the environment and cost to industry, while simultaneously maximising opportunities for productive use.
It is often assumed that the complete removal of offshore infrastructure is the best option for the environment. That’s not always the case. When an engineered structure has been part of the marine environment for an extended length of time, it has almost certainly become home to a diverse range of marine life.
Assessing how important these habitats are, and mapping out the ecosystems that exist within them, will be a vitally important piece of work that needs to be undertaken before decommissioning can begin.
The importance of connectivity
Dr Jess Melbourne-Thomas, a transdisciplinary researcher and knowledge broker with CSIRO Oceans and Atmosphere, is helping to coordinate research in this space and to connect with stakeholders. She notes that CSIRO has the capability to survey, assess and model the importance of these habitats in terms of their contribution to biodiversity, how they might support (or deter) species of particular conservation value, or how they might contribute to fisheries productivity. CSIRO also has unique tools and expertise to understand and model how different sites are connected.
“We can use connectivity models to assess the degree to which these sites might act as a network of habitats for different species, or whether they could be stepping stones – either for invasive marine species or for species that might be ‘on the move’, seeking out new habitats due to climate driven ocean warming.”
Minimising impacts from contaminants
A second area of research where CSIRO can deliver trusted advice is contaminants and containment science. As oil and gas is extracted from beneath the ocean floor, contaminants become concentrated in the pipeline. The risk of those contaminants escaping into the wider environment varies depending on whether infrastructure is removed, repurposed, or relocated. The underlying geology of each basin also has a significant impact.
CSIRO Principal Research Scientist Dr Sharon Hook, an environmental toxicology expert, has extensive experience working with the oil and gas industry. Dr Hook was lead author in the oil spill monitoring handbook which has now been adopted as Australia’s national plan for a maritime emergency, and she brings with her a depth of knowledge that translates well to decommissioning work.
“There are any number of questions we need to find answers to, many of which relate to long term issues,” says Dr Hook. “For example, drilling muds have changed substantially in the last 50 years and are much less toxic than the ones that were initially used. If we were to disturb sediment as old rigs are moved, or if the sites are opened for other uses such as fishing, will the contaminants that have accumulated create a significant health risk for marine organisms or for humans? These are really important things to know.”
Expanding blue economy opportunities
Every option for decommissioning carries its own risks, and further work needs to be carried out to understand how these can be mitigated. But it’s also important to remember that the decommissioning process offers enormous opportunities.
“When it comes to repurposing infrastructure, there’s an emerging body of research around the offshore blue economy and integrated renewable energy generation and offshore aquaculture that is very exciting,” says Dr Melbourne-Thomas.
“The potential to repurpose offshore structures to become part of a productive system is definitely there. There has also been some work done to look at towing parts of infrastructure closer to shore so they can act as artificial reefs for recreational fishers – the kind of example where CSIRO’s risk assessment capabilities would be essential.”
The ability to work at scale
Much of the work around decommissioning Australia’s oil and gas infrastructure is in its early stages, and the issue is going to remain a relevant and pressing challenge over the next few decades.
With both breadth and depth of research expertise, and a well-established history of working with stakeholders in the oil and gas industries, CSIRO is well placed to play a key role in the process.
“CSIRO excels at this kind of large-scale work,” says Dr Hook. “We have a large number of interdisciplinary scientists who are accustomed to working on complex projects in teams with people who have different specialities and skill sets. We can engage with big projects, spanning long timeframes and large geographical areas – we have specialists in temperate ecosystems and tropical ecosystems, on the East Coast and on the West Coast. The fact we have capability across so many different elements and the capacity to integrate them within the organisation translates to meaningful work and the delivery of effective science.”