Confidence needed to turn ageing oil and gas infrastructure into reefs

A review of Western Australian stakeholders has found that many are in favour of decommissioned oil and gas platforms being left to serve as artificial reefs as long as there is evidence to support the social, economic and environmental benefits.

The report was delivered by the independent Western Australian Marine Science Institution and jointly commissioned by the state government, fisheries, oil and gas, community, research, and regulatory sectors in response to the Blueprint for Marine Science 2050 report which identified better knowledge about the effects of decommissioning offshore infrastructure as a priority.

Over the next 10-20 years an increasing number of offshore oil and gas facilities around Australia will cease producing hydrocarbons and will require decommissioning. 

The process of decommissioning offshore oil and gas infrastructure is extremely expensive at a project level, and will become a major cost to the industry as a whole. Given the cost, safety issues and potential environmental risks associated with complete removal, there is interest, particularly from the oil and gas industry, in exploring other options.


Expected operational life of selected WA oil & gas projects. (Source: The Blueprint for Marine Science Report 2050. Pg 47 Estimates taken from Company Annual Reports)(Shaw et al 2018)


More than 120 stakeholders and association representatives from across sectors of the community from Perth, Exmouth, Karratha, Dampier, Port Sampson and Canberra were consulted. The group identified more than 900 issues, opportunities and concerns, which were developed into 30 questions that could be addressed through scientific research.

The priority science questions included:

  • What are the direct environmental impacts on fish species including from contamination, noise, habitat removal and cumulative ecological effects?
  • What is the timeframe for breakdown (corrosion) of the various standard components of oil and gas infrastructure?
  • What are the main contaminants following decommissioning, will they be released into the environment, and what are the toxicity issues?
  • Can the contaminants resulting from decommissioning be completely removed e.g. from sludge, scale, sands and drill cuttings?
  • Does oil and gas infrastructure (including pipelines) increase productivity of key fish species and biodiversity generally?

The consultation also identified a number of policy issues that are not science related such as managing navigation risks, who ultimately retains liability for infrastructure left in the ocean, the sharing of financial benefits from leaving infrastructure in situ and managing resource allocation of any new fisheries or environmental resources created.

A range of issues were raised in regard to improved communication with stakeholders about existing knowledge. The project also identified that a number of stakeholders were not satisfied with the current approaches to consultation regarding development operations, decommissioning activities, or policy discussion.

Lead author Dr Jenny Shaw said that while there is knowledge about the effects of decommissioning that can be drawn from the North Sea and the Gulf of Mexico, those surveyed believed it could not confidently be relied upon in Australian conditions.

“This was particularly true for issues around fisheries and environmental impacts given the uniqueness of Australian marine ecosystems,” Dr Shaw said. “The size and scale of the science questions that need to be addressed to resolve the uncertainties around decommissioning confirms that a strategic program of science projects that are unique to Australia’s offshore environment need to be developed to support company, regulator and community decisions on this subject.”

Although the information in the report was deemed to be relevant to oil and gas provinces across Australia, Western Australian stakeholder views were not assumed to be the same as those from other regions.


Shaw J.L., Seares P., Newman S.J. (2018) Decommissioning offshore infrastructure: a review of stakeholder views and science priorities. WAMSI, Perth, Western Australia. Pp 74. (