Varanus Island Hub Operations
|Activity type||Operation of a facility|
|Submitted by||Santos WA Northwest Pty Ltd|
|Submission date||13 August, 2019|
|Status||Under assessment (with NOPSEMA)|
|Link to previously accepted EP|
Phone: 08 6218 7100
Santos WA Northwest Pty Ltd (Santos WA) is the operator of the John Brookes and Greater East Spar gas fields located in offshore Commonwealth waters on the North West Shelf of Western Australia. Production fluids (gas and condensate) from these fields are transported by subsea pipelines (the John Brookes Pipeline and East Spare Pipeline) to the Varanus Island (VI) oil and gas hub (VI Hub) located in State waters.
The scope of the Varanus Island Hub Operations (Commonwealth Waters) EP comprises all activities in the EP that are associated with the operation of the John Brookes wellhead platform, associated subsea wells and pipelines. The activities will occur in Petroleum Production Licences WA-29-L, WA-45-L and WA-13-L, approximately 127 km northwest of Karratha.
The John Brookes facility is located in approximately 45 m of water. Production commenced in 2005, and the facility consists of the following:
John Brookes WHP – a normally unmanned wellhead platform designed to accommodate a maximum of six production wells;
John Brookes pipeline – a 55-km-long, routed to the VI onshore processing facilities; and
John Brookes wells – four producing wells at the John Brookes WHP.
The John Brookes facility also provides infrastructure for the control of the Halyard and Spar-2 subsea wellheads. However, production from the Halyard and Spar wells is independent of the John Brookes facility, as Halyard well fluids are exported to VI via the 65km long East Spar pipeline. Rosella-1 is an open-water, temporarily abandoned exploration well located approximately 12 km southwest of the John Brookes facility. Rosella-1 was plugged and temporarily abandoned at the time of construction in October 2007.
Varanus Island operators provide 24/7 control of the WHP via telemetry and a distributed control system from a central control building on VI. WHP visits are required for inspection, maintenance, monitoring and repair (IMMR) activities, with crews travelling via helicopter or support vessel to the WHP to carry out inspection, maintenance, monitoring and repair; to replenish fuel or chemicals; and to carry out operational requirements, such as a restart after a trip.
Ongoing IMMR within the operational area may include such activities as:
Integrity Corrosion control
Plant and subsea infrastructure cleaning, repair and modifications;
Subsea pipeline and seafloor imaging surveys
Subsea Equipment and Infrastructure Installation, Cleaning, Repair and Modification
Marine growth removal;
Inline inspections of pipelines (pigging);
Installation of replacement equipment/parts;
Installation of additional secondary stabilisation;
Topsides cleaning of facilities (both maintenance and for suspension); and
Rigless well servicing or intervention.
This EP explicitly excludes offshore drilling and decommissioning activities, which will require separate EPs when or if required.