Woodside gets go-ahead for Enfield subsea decommissioning

Australia’s National Offshore Petroleum Safety and Environmental Management Authority (NOPSEMA) has accepted Woodside Energy’s proposal for the decommissioning of subsea infrastructure at the Enfield field.

Courtesy of NOPSEMA

The proposed plan includes the removal of infrastructure above the mudline including manifolds, flowlines, umbilicals, mooring chains, and spools, and leaving in-situ 10 anchors, each including a section of mooring chain which is completely buried below the seabed.

The company also proposes contingency partial leave in-situ of manifold suction piles if determined not ALARP and acceptable to fully remove as well as inspection, monitoring, maintenance and repair (IMMR) activities, as required, until decommissioning activities are completed.

The activities are scheduled to take place between 2022 and 2024 and will take up to 12 months cumulatively, occurring during one or multiple campaigns.

The decommissioning campaign will be located in Commonwealth waters in the Exmouth Sub-basin, approximately 38 kilometres north of the North West Cape of Western Australia in water depths of approximately 400 – 600 metres.

Woodside, which operates the Enfield field within Production Licence Area WA-28-L, submitted the environmental plan on 6 January 2022.

Last month, the company contracted DOF Subsea Australia for subsea XTrees retrieval and offshore support services at the Enfield field.

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DOF Subsea will deploy its 2010-built multipurpose vessel, Skandi Hercules, to recover 18 subsea XTrees, 18 flowbases and associated spool sections, one wellhead severance and retrieve up to 18 temporary guide bases at the field.

Meanwhile, the energy giant recently received key approvals for the execution of its operated Scarborough project located offshore Western Australia.

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