Gorgon Stage Two Development Project

Gorgon Stage Two (GS2) development project is a proposed expansion of the Gorgon liquified natural gas (LNG) project, located approximately 130km off the north-west coast of Western Australia, at a water depth of around 200m to 1,300m.

Chevron holds a 47.3% stake in the Gorgon project, which includes the combined development of the Gorgon and nearby Jansz-Io fields. ExxonMobil and Shell hold a  25% stake each, while Osaka Gas (1.25%), Tokyo Gas (1%) and JERA (0.417%) hold the remaining.

GS2 is part of Chevron’s strategy to invest between $18bn and $20bn a year through 2020. The project will include the development of supplementary wells and subsea infrastructure for supporting the operations of the existing Gorgon and Jansz-Io fields. It will facilitate the expansion of the subsea gas network in order to maintain a long-term natural gas supply to the onshore Gorgon facility.

Chevron Australia and its joint venture participants agreed to go ahead with the Gorgon Stage Two development in April 2018, and plan to commence drilling works in 2019.

Gorgon Stage Two development details

The Gorgon natural gas facility expansion aims to modernise the project’s current subsea facilities to ensure sufficient production for future gas supply.

Three additional infill wells will be drilled and tied back the existing Gorgon M1 Manifold, while four wells will be tied back to a new Gorgon M4 Manifold, and four to a new Jansz Drill Centre 3 (DC-3) combined Manifold/PTS.

New infield control umbilicals will be installed at Gorgon M4 and Jansz DC-3 in addition to the installation of interconnecting flying leads to allow control of the facility.

Gorgon LNG project details

The Gorgon facility comprises an LNG plant with a capacity of 15.6 million tonnes per annum (Mtpa) and a domestic gas plant on Barrow Island in Western Australia. The $54bn project is one of the world’s biggest LNG projects and is the biggest single resource project in Australia’s history.

The offshore project has a capacity to supply 300 TJ of gas a day to Western Australia, which will be sufficient to generate electricity for 2.5 million households.

First gas production at the Gorgon project was achieved in March 2016, and transportation of domestic gas to the Western Australian market began in December 2016. Chevron commenced gas production from the second and third trains of the Gorgon LNG plant in October 2016 and March 2017 respectively.

Contractors involved

UK-based project lifecycle services provider TechnipFMC was awarded the contract for the subsea umbilicals installation of Gorgon stage two development.

Technip will be responsible for the project management and engineering, transportation, installation and pre-commissioning of umbilicals, flying leads, and manifolds, as well as manufacturing, transportation, installation and testing of rigid spools.

Baker Hughes (BHGE), a subsidiary of GE, is the supplier of subsea production equipment for the project under a 15-year Master Service Order (MSO) contract. It will also provide well completion equipment and services under a five-year contract.

Allseas was awarded the work package #1 of the Gorgon stage two, which includes the installation of production flowlines, mono-ethylene glycol (MEG) pipeline, utility pipelines, and pipeline end terminations.

The contractual scope also includes the supply of 18 anti-burial mattresses, four active pipe supports (APS) and 15 buckle initiator sleepers (BIS), as well as span correction and conducting flooding, cleaning, gauging and hydro-testing of all pipelines.

Chevron Australia has engaged Wood for providing master contractor services for the project.