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Nganhurra Operations Cessation

Activity type Decommissioning, dismantling or removing a facility
Activity subtypes Any other petroleum-related activity
Submitted by Woodside Energy Ltd
Submission date 20 December, 2019
Subtype Revision
Decision date
RMS ID 5095
Status Cancelled
Link to previously accepted EP
Daniel Clery
Phone: +61 8 9348 4000
Location map (click to enlarge)
Location map - Activity: Nganhurra Operations Cessation (refer to description)

Please Note: Following further stakeholder consultation Woodside has elected to withdraw the EP under assessment (RMS ID 5095) and submit a new revision (Revision 6). The revised EP involves a more comprehensive evaluation of the impacts and risks associated with repurposing the RTM into an Integrated Artificial Reef, as well as further consideration of the practicability of onshore disposal. Information on the new assessment is available at the following link: Nganhurra Cessation of Operations Revision

Woodside Energy Ltd (Woodside) operates the Enfield field within Production Licence Area WA-28-L. In 2018 the Nganhurra floating production, storage and offtake facility (FPSO) was utilised to flush, isolate and preserve the riser turret mooring (RTM) and the subsea infrastructure, before the FPSO was disconnected and removed from the Enfield field.

Woodside proposes to undertake the following activities in preparation for future decommissioning activities:
• inspection, monitoring and maintenance of the RTM while it remains on station
• removal of the RTM from WA-28-L following disconnection of mooring lines
• implementation of an inspection regime during preservation period until all wells are abandoned and subsea infrastructure is decommissioned (which will be subject to a future, separate Environment Plan)
• well intervention.

The RTM removal is planned to be completed between Q4 2020 and end April 2021 and is estimated to take 30 days (with potential for a cumulative 90 days when accounting for potential IMMR activities and limiting operations to periods of suitable weather conditions i.e. within cyclone season). Well intervention activities may commence from 2021, depending on vessel/MODU availability. Well intervention is estimated to take about 10-20 days per well. If undertaken as a campaign, the cumulative duration is expected to be 18 months (including mobilisation and demobilisation), and may be performed over multiple campaigns.

The Petroleum Activities Program is located in Commonwealth waters in the Exmouth Sub-basin. It is located approximately 38 km north of the North West Cape of Western Australia about 2 km to the east of the Enfield reservoir. The water depth across WA-28-L varies from 200 m in the east to over 2000 m to the west. Water depth is approximately 400 - 600 m. The Petroleum Activities Program does not overlap with any established or proposed marine protected areas. The closest nearshore sensitive habitats to the Petroleum Activities Program is the Commonwealth boundary of the Ningaloo Reef Australian Marine Park approximately 16 km to the south, the Gascoyne Australian Marine Park approximately 18 km to the west, and the Muiron Islands Marine Management and Conservation Area approximately 31 km to the south-east.

Other Details
Locations North West
Commonwealth waters adjacent to Western Australia
Titles (or other instruments) WA-28-L
Current Documents (Under assessment)
EP Document

Location map