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Australian Energy Producers Journal Australian Energy Producers Journal Society
Journal of Australian Energy Producers
RESEARCH ARTICLE (Non peer reviewed)

A path to make well-informed decisions when considering the decommissioning of subsea pipelines

Andrey Chikin A *
+ Author Affiliations
- Author Affiliations

A Xodus Group, Perth, WA, Australia.




Andrey Chikin is a Senior Decommissioning Engineer at Xodus with a double degree in Subsea and Petroleum Engineering and 10 years of experience in the oil and gas industry. He has expertise in decommissioning, regulatory requirements in UKCS and Australia, equipment maintenance, and planning of oilfield services. Andrey has worked on various projects in Siberia, Offshore Vietnam, Qatar, and Australia. He has actively participated in multiple decommissioning projects at Xodus.

* Correspondence to: andrey.chikin@xodusgroup.com

Australian Energy Producers Journal 64 S472-S476 https://doi.org/10.1071/EP23118
Accepted: 1 March 2024  Published: 16 May 2024

© 2024 The Author(s) (or their employer(s)). Published by CSIRO Publishing on behalf of Australian Energy Producers.

Abstract

Australia’s law mandates the removal of infrastructure once not in use unless the Titleholder can demonstrate an equal or superior safety and environmental outcome. Around 100 infield and export pipelines in Australian waters, with an approximate total length of 5000 km, are nearing their end-of-life period. Three common decommissioning options are considered for subsea pipelines: complete removal, partial removal, or in-situ abandonment. Decommissioning these pipelines will cost an estimated US$13 billion, ~33% of the cumulative Australian offshore decommissioning liability, should the full removal option be selected. When decommissioning subsea pipelines, it is essential to consider that they have been exposed to hazardous fluids and aggressive environments. Careful assessments should determine the recyclability of recovered materials, decontamination, and the environmental risks associated with each decommissioning option. A holistic approach is needed to identify and quantify contaminants in subsea pipelines. In the early stages of decommissioning, planning, sampling, and laboratory testing are necessary to identify plastic coating types, degradation mechanisms, constituents released to the environment, types and mechanisms related to mercury/naturally occurring radioactive materials, and chemical stability. This paper aims to identify and present effective methods for addressing the impact of pipeline constituents on the Marine Environment Assessment while assessing potential decommissioning options and explains how tools can support decision-making. In summary, decommissioning subsea pipelines requires careful assessment and planning to ensure environmental and safety compliance. The paper provides a guide to understanding the process, highlighting the importance of quality assurance, risk assessment, and the selection of appropriate decommissioning options.

Keywords: contaminants evaluation, corrosion coating, decommissioning, degradation, environmental plan, mercury, NOPSEMA, NORMs, planning, polymer, subsea pipelines.

Biographies

EP23118_B1.gif

Andrey Chikin is a Senior Decommissioning Engineer at Xodus with a double degree in Subsea and Petroleum Engineering and 10 years of experience in the oil and gas industry. He has expertise in decommissioning, regulatory requirements in UKCS and Australia, equipment maintenance, and planning of oilfield services. Andrey has worked on various projects in Siberia, Offshore Vietnam, Qatar, and Australia. He has actively participated in multiple decommissioning projects at Xodus.

References

Bamford CH, Tipper CFH (1975) ‘Comprehensive Chemical Kinetics. Vol. 14.’ (Elsevier)

CODA (2021) A Baseline Assessment of Australia’s Offshore Oil and Gas Decommissioning Liability. Centre of Decommissioning Australia. Available at https://www.decommissioning.org.au/wp-content/uploads/2022/08/Offshore-Oil-and-Gas-Decommissioning-Liability.pdf

DISER (2022) ‘Guideline: Offshore petroleum decommissioning.’ (Department of Industry, Science, Energy and Resources, National Offshore Petroleum Titles Administrator) Available at https://www.nopta.gov.au/_documents/guidelines/Offshore-Petroleum-Decommissioning-guideline.pdf

Gissi F, Koppel D, Boyd A, Kho F, von Hellfeld R, Higgins S, Apte S, Cresswell T (2022) A review of the potential risks associated with mercury in subsea oil and gas pipelines in Australia. Environmental Chemistry 19, 210-227.
| Crossref | Google Scholar |

NOPSEMA (2014) The Regulator, Issue 3. Available at https://www.nopsema.gov.au/sites/default/files/documents/2021-04/A369617.pdf

NOPSEMA (2020) Guidence Note N-04750-GN1344 A339814, Environment plan content requirement. Available at https://www.nopsema.gov.au/sites/default/files/documents/2021-03/A339814.pdf