WOODSIDE has accelerated planning for a proposed development of the giant Scarborough gas field off the Western Australian coast.
In announcing the company’s latest Quarterly report, Woodside CEO Peter Coleman said the company has accelerated target ready for start-up to 2023 for the upstream component of the Scarborough development and 2024 for the downstream to maximise the market opportunity.
“We have also increased the design capacity of the proposed Pluto Train 2, to four to five million tonnes per annum,” Mr Coleman said.
Fast-tracking is also occurring with agreements to potentially toll Browse gas though the North West Shelf facilities on the Burrup Peninsula.
“Subsequent to the quarter alignment has been reached between the North West Shelf participants on non- binding key commercial terms and pricing for processing third-party gas through NWS infrastructure.
“A preliminary tolling agreement is expected between the NWS Project participants and Browse Joint Venture in Q3 2018,” Mr Coleman said.
Woodside is proposing to develop the Scarborough resource with 12 subsea, high-rate gas wells tied back to a semi-submersible platform moored in 900 m of water. The ~20,000 t topsides has processing facilities for gas dehydration and compression to transport the gas through a ~400 km pipeline to the Woodside operated Pluto LNG facility.
The Scarborough resource has been fully appraised and the reservoir consists of excellent quality sands which support recoverable volumes in excess of 0.5 Tcf per well. The Scarborough gas reservoir is relatively shallow at only 900 – 1,000 m below the mudline. The lean reservoir gas is classified as ‘sweet’ with no detectable H2S and only trace levels of CO2.
A phased development drilling program is proposed, with seven wells available at ready for start-up (RFSU). Given the shallow depth below the mudline and anticipated strong aquifer support, a combination of horizontal and high angle wells have been designed with maximum well lengths
of ~2,500 m. The well and completion designs align with Woodside’s extensive development experience offshore north-western Australia.
The proposed carbon steel trunkline will be ~400 km long, significantly shorter than recently constructed offshore gas pipelines in the region. Woodside’s ongoing subsea development programs in the North West Shelf and Exmouth area provide contemporary analogues for cost and execution schedule estimates. The seabed transition zone from the deep water to the North West Shelf is well known to Woodside after previous successful projects in the area. In preparation for future expansion, Pluto LNG constructed a shore crossing for a second trunkline.
In March Woodside completed the acquisition of ExxonMobil’s interest in the Scarborough gas field, providing the company with an additional 50% interest in WA-1-R (which contains the majority of the Scarborough gas field), and now holds a 75% interest in WA-1-R and a 50% interest in WA-61-R, WA-62-R and WA-63-R. These retention leases cover the Scarborough, Thebe and Jupiter gas fields, which are estimated to contain gross (100%) contingent resources (2C) of 9.2 Tcf of dry gas. Woodside will operate all of these retention leases.