Preparing for first export: the QCLNG Project

Overview of the QCLNG site with the Pipeline Delivery Station in the foreground.

Overview of the QCLNG site with the Pipeline Delivery Station in the foreground.

This year promises to be a landmark for Australia’s export LNG industry, particularly for BG Group’s $US20.5 billion Queensland Curtis LNG Project, which remains on schedule for first LNG in the 2014 fourth calendar quarter.

The LNG processing plant and export terminal at Curtis Island will have an initial production capacity of 8.5 MMt/a of LNG from two trains, with provision for a third train. First LNG is expected from the project in the final calendar quarter of 2014, with the second LNG train expected to come online about six months later. BG Group plans to produce up to 210,000 barrels of oil equivalent per day (boe/d) net from the first two trains.

The project also involved expansion of gas production in the Surat Basin of southern Queensland, and construction of a 540 km underground pipeline network.

The CSG supply to feed the project is being sourced from the Surat Basin tenements involving 6,000 wells over more than 4,500 sq km of tenements by 2030, including an initial 2,000 wells by the end of 2014.

The project has the potential for expansion up to 12 MMt/a of LNG, subject to additional gas reserves.

First gas achieved

In December 2013, BG Group successfully reached a key milestone in the development of the Queensland Curtis LNG (QCLNG) Project, with first gas transported from the Surat Basin to Curtis Island where the liquefaction terminal is located.

Delivery of first gas to the island marked the successful completion of a two-year task to lay more than 46,000 lengths of one-metre diameter steel pipe over 540 km – the longest large-diameter buried pipeline in Australia.

The arrival of gas enables commissioning to begin on the first of two LNG production trains being developed by the Group as part of the integrated QCLNG Project.

Commenting on the milestone, BG Group Chief Executive Chris Finlayson says “To have first gas on Curtis Island in a little over three years from project sanction is an immense achievement. It is a testament to the expertise and dedication of everyone working on this vast and complex mega-project.

“Delivering this key milestone demonstrates the advanced stage of development at the world’s first CSG-to-LNG project. We are now entering the final construction and commissioning phases.”

BG Group’s Australian business, QGC, is the operator and holds majority ownership of the QCLNG Project, with Chinese state-owned oil and gas producer CNOOC and Japan’s Tokyo Gas holding minority stakes.

In particular, BG Group holds around 74 per cent interest in the upstream resource and related infrastructure, 100 per cent of the project’s common facilities on Curtis Island (including LNG storage tanks and jetty), and the 540 km natural gas pipeline network linking the gas fields to Curtis Island.

CNOOC holds a 50 per cent equity interest in Train 1 and up to 25 per cent interest in certain upstream tenements held by BG Group in the Surat and Bowen basins. CNOOC also holds the option to participate up to 25 per cent in one of the potential expansion trains at QCLNG.

Japan’s Tokyo Gas holds a 2.5 per cent interest in the second train and a 1.25 per cent interest in certain upstream tenements held by BG Group in the Surat Basin.

In the pipeline

The 42 inch, 540 km underground steel pipeline for the QCLNG Project is made up of a 200 km gas collection header and a 340 km export pipeline. The gas collection header starts near Dalby and follows a northern route to near Wandoan.

The pipeline design features include:

  • AS2885 Part 1, 2, 4 and 5 – the Australian Standard for the design and construction of petroleum pipelines.
  • DN1050 mm API 5L PSL2 manufactured using UOE process wall thicknesses of 14.1 mm, 18 mm and 23.5 mm.
  • Pipeline using 0.8 design factor for 14.1 mm wall thickness:18 mm used for road crossings and high consequence areas, 23.5 mm used for horizontal directional drillings (HDD) and the Narrows Crossing.
  • Designed for clean, dry natural gas.
  • Coated with 800–1,000 microns of dual layer fusion-bonded epoxy.
  • Internally lined with 85 microns of epoxy flow liner.
  • Induction bends used for horizontal bends >40 degrees.
  • Pipe joint coating system SPC 2888 – applied by PIH.
  • Five laterals and eight mainline valves including the Receipt Station near Wandoan and the Delivery Station on Curtis Island.
  • Electric cathodic protection system to help prevent corrosion.

Crossing at The Narrows

The QCLNG Pipeline Project has set records for Australian pipeline construction, including the longest twin pipe-pull in the country, when the 2.3 km Narrows channel in Gladstone Harbour was crossed in early 2013.

The Narrows project involved four other sections on the mainland, including conventional construction, HDD under a creek section, and a cofferdam through marshlands, as well as conventional construction on Curtis Island.

The pipe has a wall thickness of 23.5 mm, and has a heavy concrete weight-coating with a density of 3,044 kg/m3, which is used to maintain the submerged stability of the pipeline.

QCLNG pipeline network

  • 46,200 individual 12 m lengths, each of four tonnes;
  • 1,100 crossings of creeks, roads, access tracks, railway lines and third-party utilities and passing through 580 fences;
  • Workforce of more than 1,700 at peak construction for a total of 12 million working hours;
  • Project vehicles travelled more than 44 million km;
  • Buried with between 0.75 m and 1.5 m of cover, depending on terrain and land use, with cover of more than 1.5 m at creek, road and railway crossings;
  • FBE coating and cathodic protection to prevent corrosion;
  • Remotely activated valves at least every 90 km for shutdowns;
  • Operation constantly monitored from QGC’s Chinchilla operations centre; and,
  • Regular inspections from air and on ground.
Enter your details to subscribe to the free fortnightly Gas Today e-newsletter

Thank you for signing up for the Gas Today Online Update.