Chevron Australia has reached final investment decision (FID) on a $4-billion project to add compression to maintain gas flow from Jansz-Io fields in the Carnarvon basin off Western Australia.

Describing the development as a modification of the existing Gorgon development, Chevron said compression work will include construction and installation of a 27,000-tonne normally unattended floating field control station along with 6,500 tonnes of subsea compression infrastructure and a 135-km submarine power cable linked to the operations base on Barrow Island.

Construction and installation are expected to take 5 years to complete. Work will begin in second-half 2022.

Jansz-Io compression work follows the Gorgon Stage 2 project which is nearing completion of the installation phase to supply gas to the Gorgon LNG and domestic gas plants on Barrow Island from four new Jansz-Io and seven new Gorgon wells.

Chevron is operator of the Gorgon project with 47.333% interest. ExxonMobil and Shell each have 25%. Osaka Gas holds 1.25%, Tokyo Gas holds 1%, and JERA holds 0.417%.