Wheatstone project

Australia is endowed with vast, offshore natural gas reserves; as a result, it has attracted many global oil companies that are investing in huge projects. The Wheatstone project, located near Onslow in northwestern Australia, is one of those huge investment projects. The objective is to build infrastructure to liquefy natural gas for commercial purposes. Following several success stories in this sector over the past 30 years, VINCI Construction Grands Projet and Entrepose Contracting were asked to provide engineering, supply logistics, and construction services for two double-walled storage tanks for liquefied natural gas (LNG), each with a capacity of 150,000 cubic metres and two storage tanks for condensates, each with a capacity of 120,000 cubic metres.

BACKGROUND

Until the mid-1960s, the volume of natural gas in its gaseous state was the main obstacle to its transport and, therefore, to its development as a saleable commodity. In most cases, producing countries were very distant from consuming countries; as a result, for many years, the buying and selling of natural gas was a difficult business sector to develop. Today, liquefaction has led to the development of the LNG supply chain from exporting countries to importing countries.
Today, thanks to certain types of infrastructure, we can cool natural gas to a tempoerature of minus 161°C, thereby reducing its volume by a factor of 600. Liquefaction plays an important role in the global energy industry because there are vast reserves of natural gas around the world, and in its condensed state, it can easily be transported by sea across vast distances. This is the context in which the Wheatstone project was developed; its objective is to make Australia the world’s leading producer of LNG.

TECHNICAL OVERVIEW

Storage tanks work like a giant thermos. They consist of a filling system and a pumping system that conveys the LNG to a pressure relieve valve (PRV).
All gas pipes are thermally insulated to maintain the LNG at minus 161°C in an environment where the outside temperature can rise to more than 50°C. The structure includes other related systems and equipment (fire extinguishors, instrumentation, electrical power, maintenance crane, heating of the concrete footing, and more).
A storage tank has an inner tank, a sheet steel construction that also contains nickel (9%). The inner tank is insulated by a low-density (50 kilograms per cubic metre) perlite coat. Bottom insulation using cellular glass consists of low-density uninflammable materials. The inner tank’s metal shell (vapour barrier/liner) is a carbon alloy steel impermeable to gas designed to prevent gas leaks. The outer tank is made of prestressed concrete designed to support the entire structure and withstand earthquakes.
From a technical standpoint, the use of climbing formwork for the coating is an effective construction method but is highly complex, especially in the case of a storage tank measuring 88 metres in diameter and 37 metres high. As for the mechanical works, the Entrepose Contracting team carried out the roof-lifting operations perfectly; each roof was a huge dome measuring 5,700 square metres and weighing 850 tonnes. The lifting operations, which raised the roofs 35 metres above the ground, were performed in just two hours thanks to the use of two fans that created a slight upward pressure of 20 millibars.

In compliance with Australia’s very stringent regulations, we applied the zero accidents plus (ZAP) policy, for example, an in-vehicle monitoring system was placed in every vehicle to alert drivers, in real time, of unfastened seatbelts or speeding.

IMPACT

In the past 20 years, VINCI Construction Grands Projets and Entrepose Contracting have built more than 30 LNG storage tanks in 10 different countries. This latest achievement, therefore, is built on a wealth of expertise in this field.
These storage tanks in Australia are among the largest infrastructure in the country dedicated to the development of natural resources. This infrastructure should create at least 475 jobs in the region of Pilbara in Western Australia.
On this project, 75% of job recruits were from Australia, including 55% from Western Australia. The Aboriginal community was actively involved in the project. Indirect jobs associated with the LNG trade in Australia will also be created.
In a few years, Australia should surpass Qatar as the leading LNG producer in the world. Australia is where seven of the eleven current LNG-related construction projects in the world are located; in all, these seven projects will produce 61.8 million tonnes of LNG a year. By 2018, Australia’s production capacity should reach 86 million tonnes a year, while Qatar’s will remain stable at 77 million tonnes.

Project participants

Client
Chevron Australia Pty Ltd

Project management
Bechtel Australia

Key figures

Implementation dates
July 2013 to October 2016

LNG storage tanks
2 x 150,000 m3

Condensate storage tanks
2 x 120,000 m3

Testimonial

“One of the main challenges was to manage teams based in Paris, Perth, and Onslow and get them to communicate with one another, while also integrating a great many suppliers and subcontractors from all over the world, including Europe, the United States, China, Thailand, and other countries and our client whose head office is in Houston, Texas.”

Aurélien Delevoye, ASSISTANT PROJECT DIRECTOR

Find out more

www.chevronaustralia.com

www.chevron.com