North West Shelf Project

Representing an investment of A$27 billion, the North West Shelf Venture facilities constitute Australia's largest oil and gas resource development and currently account for more than 40 per cent of Australia's oil and gas production.

The North West Shelf Venture supplies oil and gas to Australian and international markets from huge gas and condensate fields in the Carnarvon Basin on Australia's northwest continental shelf.

With an international reputation for the safe and reliable delivery of LNG to customers in the Asia Pacific region, the Venture has delivered more than 2,400 LNG cargoes since 1989 and also produces condensate and oil for the international energy markets.

For almost 25 years the Venture has been Western Australia's largest producer of domestic gas, and currently provides about 65 per cent of total State production. The Venture also produces LPG for the world market and for Western Australia.

In 2009 the North West Shelf Venture will celebrate 25 years of safe and reliable domestic gas supply to Western Australia, and 20 years of LNG supply to North Asia.

Onshore facilites

Karratha Gas Plant

The Venture's facilities include the Karratha Gas Plant, one of the most advanced integrated gas production systems in the world, where LNG, domestic gas, condensate and LPG is produced.

Located 1,260km north of Perth, Western Australia and covering approximately 200 hectares, the Karratha Gas Plant facilities include five LNG processing trains (including two which also process domestic gas), five condensate stabilisation units, two LPG fractionation units as well as storage and loading facilities for LNG, LPG and condensate.

LNG plant

Built in 1984, the Karratha Gas Plant has an annual LNG production capacity of 16.3 million tonnes and includes five LNG processing trains, four heavily insulated storage tanks each with a gross capacity of 65,000m3 and a dedicated LNG jetty with two loading berths. Trains 1, 2 and 3 each have a production capacity of 2.5mtpa while Trains 4 and 5 can produce up to 4.4 million tonnes annually.

Key elements of each LNG train include the sulphinol units, which remove carbon dioxide from the gas; dehydration units for the removal of water; a mercury removal unit; a scrub column, which removes the heavier gases; a liquefaction unit, which reduces the temperature of the gas from minus 35ºC to minus 130ºC; and two end flash vessels, where a reduction to atmospheric pressure leads to further cooling, achieving the cold temperature boiling point for methane of minus 161ºC. At this point, the gas condenses to a liquid at 1/600th of its gaseous volume and is stored before being piped to the LNG jetty for offloading onto purpose-built LNG carriers for transport to Japan, China and South Korea.

Domestic gas plant

One of the largest of its type in the southern hemisphere, the domestic gas plant consists of two parallel processing trains which together are capable of producing over 600 terajoules or 10,000 tonnes of domestic gas per day.

Natural gas is piped from offshore reserves at the North Rankin A, Goodwyn A and Angel platforms and the Cossack Pioneer FPSO through the Karratha trunkline where it is processed onshore into gas suitable for domestic sale.

Gas is delivered via the 1,500km Dampier to Bunbury Natural Gas Pipeline which was completed in 1984 and transports gas to major industry users and more densely populated areas in Perth and Western Australia's south-west.

The North West Shelf Venture currently provides about 65% of Western Australia's total gas production.

Condensate plant

Condensate is a very light crude oil which condenses from natural gas when it encounters normal atmospheric conditions. It is sold on the spot market, mainly to oil refineries in Australia and overseas, and is used as a feedstock for chemical plants and in the manufacture of automotive and aviation fuels.

The Venture's condensate facilities include five stabiliser plants with a combined capacity of 130,000 barrels per day, four floating-roof storage tanks and six condensate loading and circulating pumps, condensate loading lines and loading arms. A sixth stabiliser train is currently under construction, and is expected to commence operation in the first half of 2009.

LPG plant

The LPG facilities consist of three fractionation trains, chilling facilities, two storage tanks and a ship-loading jetty for LPG and condensate.

Most of the LPG produced goes into a 52,000m3 propane storage tank and a 65,000m3 butane storage tank for eventual refrigerated export.

LPG consists of propane and butane gas and is commonly used for heating, cooking and automotive fuel. Some LPGs are used in the domestic gas supply and some are used on-site as a refrigerant gas in the liquefaction process.

Offshore facilities

The Venture's offshore production facilities include the North Rankin A, Goodwyn A and Angel platforms, and the oil producing Cossack Pioneer floating, production, storage and offloading (FPSO) facility. Hydrocarbons from the offshore platforms are

transported to the Karratha Gas Plant for processing via two subsea pipelines, otherwise known as trunklines. North Rankin A platform

The massive North Rankin A platform is one of the largest capacity gas production platforms in the world and serves as the central hub of the Venture's offshore gas production system.

Located 135km north-west of Karratha, North Rankin A stands in 125m of water at a total height of 215m and combines drilling, production, utilities and accommodation facilities.

North Rankin A produces gas and condensate from the North Rankin and Perseus fields and has a daily production capacity of up to 51,000 tonnes of gas and 5,800 tonnes of condensate. A trunkline system transports dry gas and condensate from North Rankin A to the Karratha Gas Plant for processing.

In March 2008 the North West Shelf Venture approved funding for the North Rankin Redevelopment Project which will access additional recoverable reserves by recovering remaining low pressure gas from the North Rankin and Perseus gas fields, and extend the field life to around 2041.

The project involves the installation of a second platform - North Rankin B - which will be connected by a 100 metre bridge to the existing North Rankin A platform. North Rankin B is scheduled for progressive start-up in 2013 and on completion, both platforms will be operated as a single integrated facility known as the North Rankin hub. The redevelopment scope also includes the necessary tie-ins and refurbishment of the North Rankin A platform.

Goodwyn A platform

The Goodwyn A platform is connected to the condensate-rich Goodwyn gas field located 23km south west of the North Rankin A platform and about 135km north west of Karratha.

The platform stands over 291 metres tall in a water depth of 131 metres and combines drilling, production, re-injection, utilities and accommodation facilities, It has a daily production capacity of up to 34,500 tonnes of gas and 18,000 tonnes of condensate.

Dry gas and condensate produced from the Goodwyn area reservoirs and Echo/Yodel and Perseus satellite field reservoirs are exported to the nearby North Rankin A platform by an interfield pipeline, before being transported to the Karratha Gas Plant for processing. In 2007 production began from the Perseus and Searipple wells via the Perseus-over-Goodwyn pipeline which connects these wells to the Goodwyn A platform.

Angel platform

The Angel platform - the Venture's newest offshore gas production facility - is located about 120km north west of Karratha.

The remotely operated platform is tied in to the first trunkline at the North Rankin A platform via a 50km subsea pipeline and is designed to allow for the tie-back of other discoveries in the area.

Angel stands in about 80 metres of water and is supplied by three subsea production wells. Its unique design enables it to be safely and securely powered and remotely controlled from North Rankin A via a subsea cable.

Hydrocarbons are produced through one 'dry export' processing unit with a daily capacity of up to 800 million standard cubic feet of gas and up to 50,000 barrels of condensate, and are processed onshore at the Karratha Gas Plant.

Cossack Pioneer FPSO

Located 34km east of the North Rankin A platform, the Cossack Pioneer floating production storage and offloading facility and is moored to a riser turret between the Wanaea and Cossack oil fields.

Connected by flexible flowlines to subsea wells on the Cossack, Wanaea, Lambert and Hermes fields, which have produced 395 million barrels of oil since production began in 1995, the Cossack Pioneer has a daily production capacity of up to 150,000 barrels of oil, 4,000 tonnes of gas and a storage capacity of 1.15 million barrels of oil.

Crude oil is offloaded from the vessel via a flexible line to bulk tankers moored astern, while a pipeline exports LPG-rich gas from the Cossack-Wanaea fields to the North Rankin A platform, before being transferred to the Karratha Gas Plant for processing.

In December 2008 the CWLH joint venture approved funding for the North West Shelf Oil Redevelopment project which involves the replacement of the Cossack Pioneer FPSO in 2010, and the refurbishment of associated subsea infrastructure. The project will support ongoing safe and reliable production from the Cossack, Wanaea, Lambert and Hermes fields beyond 2020.