Yamal LNG

The Yamal peninsual is located 400 kilometres north of the Arctic Circle in western Siberia in the Gulf of Ob. It is in this region, which is iced over nine months a year, that the Yamal LNG project is being carried out. Our mandate is to design, supply equipment, materials, and provisions, and build and equip four double-walled cryogenic tanks, each with a capacity of 160,000 cubic metres, to store liquefied natural gas (LNG). An innovative approach allowed us to reduce in half the number of foundation piles needed for this atypical ground, namely, permafrost. In less than a year and a half, the contract was signed, the team was mobilised, foundations were designed and built, and the civil engineering for the tank chambers was completed.

BACKGROUND

In May 2013, two VINCI Construction companies (VINCI Construction Grands Projets and Entrepose Contracting) were awarded a contract by JSC Yamal LNG to provide engineering, equipment and material supply, construction, and implementation of the cryogenic tanks, each with a capacity of 160,000 cubic metres. The two companies work together well, having achieved many similar projects, including, for example, the Wheatstone project in Australia.
The Yamal LNG project calls for the construction of a liquefied natural gas production station of a capacity of 16.5 million tonnes a year on the South Tambey gas field. According to estimates, the gas field contains 907,000 million cubic metres of natural gas, which is why this project is critically important.

TECHNICAL OVERVIEW

First and foremost, our effective engineering solution for the storage tank foundations was a decisive criterion in winning this contract. We put forward a solution that halved the number of piles required and reduced their required depth from 37 to 24 metres. This gave us a strong cost advantage as this solution helped achieve significant savings in materials. Our foundation solution for permafrost (frozen soil at depth) called for 950 piles per tank at a depth of 24 metres.
The second key point in this project was our capacity to carry out works in extreme weather conditions. Accordingly, the storage tanks were developed using sliding formwork. Thanks to this technique, we were able to pour concrete 24 hours a day, allowing us to work faster than if we had used climbing formwork. Im addition, drilling in permafrost was a delicate operation since any disruption to the natural equilibrium in the ground could have led to heating the ground and, later, jeopardising the stability of the foundations. To overcome this difficulty, we implemented a thermostabilisation solution as well as a system to offset thermal dilation. The storage tank was placed 2 metres above the ground; the ground itself was made up of a 2-metre layer of backfill above the permafrost. This approach prevented disruption of the permafrost’s thermal equilibrium. In addition, between each pile, we installed a 24-metre-long thermostabiliser that can keep the permafrost at temperatures below minus 5°C for a period of 50 years.

To prevent heating the soil, which would jeopardise the stability of the foundations, we recommended the use of “socks” to sheathe the piles and increase flexibility in the 2-metre layer of backfill that covers the permafrost. This new process earned us a 2015 VINCI Innovation Award in the processes and techniques category.

IMPACT

As our LNG-construction activity demonstrates, the Yamal LNG project is an integral part of our service offering and know-how. However, this was the first time that we had to work in such conditions, including permafrost and severe logistical challenges.
The Yamal peninsula is Russia’s leading site for hydrocarbon-related operations. This infrastructure is designed to open up access to the immense gas resources in Russia’s Arctic region by creating a new transport route by sea to Europe and Asia.
The project enables VINCI Construction Grands Projets to display its capacity to implement complex structures in extreme weather conditions (with temperatures as low as minus 40°C in winter). In fact, we’re one of the very few companies in the world today that can deliver this type of project.

Project participant

Client
JSC Yamal LNG

Key figures

Implementation dates
June 2013 to December 2017

Capacity per unit
160,000 m3

Number of storage tanks
4

Concrete per storage tank
17,500 m3

Testimonial

“Our ability to provide a compelling solution for storage tank foundations was decisive in winning this contract. Our ability to pour concrete effectively in extreme conditions worked in our favour.”

Hosni Bouzid, DIRECTOR LNG STORAGE TANKS