Australian oil and gas firm Woodside has awarded Boskalis a contract for seabed intervention and shore crossing for the proposed pipeline at the Scarborough field, one of the most remote of the Carnarvon Basin gas resources offshore W. Australia.

Woodside’s preferred concept for the development of the 7.3 Tcf (2C 100%) Scarborough gas resource is through new offshore facilities connected by an approximately 430 km export pipeline to the Burrup Peninsula with onshore processing at the expanded Pluto LNG facility. Woodside is the operator of the project with a 75 percent stake.

Under the contract awarded to Boskalis,  the Dutch marine and dredging contractor will be responsible for preparatory activities related to offshore deepwater excavation, pipeline crossings, nearshore, and shore crossing works for the export trunkline which connects Scarborough to onshore processing infrastructure.

The actual execution of the in-field work depends on a positive final investment decision being taken on the project by the Scarborough partners.
Boskalis will deploy specialist excavation and rock placement equipment for the complex scope, presenting a substantial local employment component. The scope also includes the supply of rock material.

Boskalis said that the contract potentially carried a value of 145 euros million if all options were called. Woodside is targeting a final investment decision in 2020 and ready for start-up (RFSU) in 2023.

The seabed intervention and shore crossing works are scheduled to start in March 2021 with an expected completion mid-2022, Boskalis said.

Boskalis said it would deploy a trailing suction hopper dredger, a backhoe dredger, a dynamically positioned fallpipe vessel and rock installation vessel, survey vessels and an offshore construction vessel for the project.

The Scarborough gas field is situated approximately 375 kilometers offshore the Burrup Peninsula in northwest Australia. The proposed export pipeline will transport natural gas between the Scarborough Floating Production Unit and the onshore processing plant.

Public comment sought

The Australian offshore safety regulator NOPSEMA has recently invited public comments for Woodside’s proposed Scarborough development.

The oil and gas company is proposing to develop the field hrough the construction of a number of subsea, high-rate gas wells, tied back to a semi-submersible floating production unit moored in approximately 900 meters of water close to the Scarborough field.

Woodside’s proposed Scarborough development targets the commercialization of the Scarborough and North Scarborough gas fields. There are also Thebe and Jupiter gas fields nearby, but, according to Woodside, they provide opportunities for future tieback to Scarborough infrastructure.

The offshore facilities, to be newly built, are proposed to be connected to the mainland through an approximately 430 km trunkline (also refers to as the export pipeline) to an onshore facility.

Woodside has already found a buyer for a portion of natural gas to be produced from the Scarborough field. The company in November 2018 entered into a long-term gas sale and purchase agreement (GSPA) with W. Australia-based Perdaman for the supply of pipeline gas for a term of 20 years.

The first drilling phase is targeted in 2020 followed by the installation of the trunkline in 2022, FPU installation in 2023 and phase 2 drilling (potentially including Thebe and Jupiter) in 2025. Decommissioning is expected to begin in 2055.

Public comments can be submitted until 30 August 2019 via NOPSEMA’s online form.