Gorgon-Gasprojekt

Approximate location of some of the Greater Gorgon gas fields in relation to Barrow Island and the adjacent coastline of Western Australia

The Gorgon gas project is a proposed petroleum project in Western Australia, involving the development of the Greater Gorgon gas fields, subsea gas-gathering infrastructure, and the construction of a liquefied natural gas (LNG) plant on Barrow Island.

Location

'Greater Gorgon' refers to a grouping of several gas fields, including Gorgon, Chrysaor/Dionysus, Jansz, Io, West Tryal Rocks and Spar. They are situated within the Barrow sub-basin (part of the Carnarvon Basin), also known as the North West Shelf. The Gorgon field is centred about Vorlage:Convert off the north-west coast of Western Australia, where the water depth is approximately Vorlage:Convert, although other fields forming part of the Greater Gorgon group lie in deeper water to the north-east. Jansz-Io, which covers an area of about Vorlage:Convert, is in a location where the water depth is Vorlage:Convert.

Barrow Island is situated off the Pilbara coast, Vorlage:Convert north-north-east of Onslow and Vorlage:Convert west of Karratha. The largest of a group of islands which include the Montebello and Lowendal Islands, it is approximately Vorlage:Convert long and Vorlage:Convert wide and covers an area of Vorlage:Convert.

Gas from the Gorgon gas fields will be delivered (via subsea pipelines) to the west coast of Barrow Island, then via an underground pipeline system to the east coast of the island, where it will tie in to gas treatment and liquefaction facilities.

History

More than 200 exploration wells have been drilled in the Barrow sub-basin over the past 35 years, including West Tryal Rocks in 1972, and Spar in 1976 - both discovered by West Australian Petroleum (WAPET) which had been a pioneering company in the development of the Western Australian petroleum industry. WAPET was the operator on behalf of various joint ventures comprising Chevron, Texaco,Shell and Ampolex. In 2000, Chevron became the operator of all WAPET's petroleum assets.

WAPET discovered Gorgon in 1980, and its size was confirmed with the drilling of the Gorgon 1 well in 1981. Later discoveries included Chrysaor (1994) and Dionysus (1996). The super giant Jansz-Io accumulation, discovered in January 2000, contains an estimated 566 billion cubic meters of recoverable reserves.

In September 2007, the Gorgon gas project received preliminary approved from the West Australian government, and by the Federal Minister for the Environment in the following month. The project received final approval from the state government on 11 August 2009.

Project scope

Chevron plans to extract gas from the Gorgon gas field, and the Jansz–Io gas fields (operated by Mobil Australia Resources Company), using up to 30 subsea wells. Subsea gathering systems and subsea pipelines will be installed to deliver gas to a gas treatment plant at Barrow Island, comprising 3 liquefied natural gas (LNG) trains, each capable of producing a nominal capacity of five million tonnes per annum (MTPA). The plant will also produce condensate and domestic gas.

Carbon dioxide (CO₂), which occurs naturally in the feed-gas, will be separated during the production process. The separated CO₂ will then be injectedinto deep formations below Barrow Island. The LNG and condensate will be loaded from a dedicated jetty then transported by dedicated LNG carriers to international markets. In a later pahse of the project, gas for domestic use will be exported by a pipeline from Barrow Island to domestic transmission networks on the mainland.

If the project proceeds, it will become Australia's third LNG development.

Project companies

Development of the Gorgon Project is being pursued by the Australian subsidiaries of three international energy companies. Chevron Australia is the operator and project proponent, on behalf of the the Gorgon Joint Venture partners:

• Chevron Australia (a subsidiary of Chevron) (50%)
• Shell Development Australia (a subsidiary of Royal Dutch Shell) (25%)
• Mobil Australia Resources (a subsidiary of Exxon Mobil) (25%)

Gas sales

LNG export agreements

Numerous agreements have been reached between the joint venturers and customers in China, India, Japan and South Korea. PetroChina has agreed with Shell to buy 1 million tonne of LNG per annum.Osaka Gas will buy 1.5 million tonnes of liquefied natural gas per annum and Korea's GS Caltex will buy 0.25  million tonnes of liquefied natural gas per annum from Chevron.

An agreement was signed with Petronet LNG to supply 1.5 million tonnes of LNG per annum for 20 years to the Kochi LNG Terminal, for A$25 billion.

A significant milestone was reached in August 2009 with the signing of a sales and purchase agreement (SPA) between ExxonMobil and PetroChina. The contract is the largest individual export deal in Australia's history, and provides for the supply of 2.25 MTPA of LNG for 20 years, and is valued at AU$50bn.

Domestic gas

Under the terms of a schedule forming part of the Barrow Island Act, the joint venturers are required to reserve gas sufficient to deliver 2000 petajoules of gas to the mainland, for consumption in the domestic market. The current project scope, as submitted for the environmental approval process, does not include a domestic gas plant on Barrow Island nor an export pipeline to the mainland, although Chevron's documents refer to these facilities as being anticipated at some stage in the future.

Controversy

The proposed project has attracted criticism from conservation groups in relation to the potential impact upon Barrow Island, which is a Class A nature reserve. It is home to the flat-backed turtle (a threatened species) and numerous other animals.

External links

• Gorgon Project website
• Barrow Island Act (2003)