Plenty of scope for offshore carbon storage

26.01.2012
The Norwegian sector of the North Sea could accommodate as much as 70 billion tonnes of carbon dioxide, according to a storage atlas for this greenhouse gas produced by the NPD.
  • Astri Sivertsen and Emile Ashley (photo)

Eva Halland

Storage.
Eva Halland at the NPD has led the work to confirm secure geological formations which can hold carbon dioxide volumes equal to Norway’s total emissions for 20 years.

 

The new publication represents the first overall presentation of where and how much carbon dioxide could be stored beneath the seabed off Norway.

Ole Borten Moe, the Norwegian minister of petroleum and energy, characterised the NPD’s work as “groundbreaking” when receiving a copy of the atlas on 13 December.

Mr Moe noted that Norwegian specialists have great expertise on carbon storage, partly because it has been under way on Sleipner East and Snøhvit since 1996 and 2008 respectively.

The atlas provides an overview of relevant areas in the Norwegian North Sea. It maps 21 geological formations and assesses their storage capacity and resistance to leaks.

An important condition has also been that such storage should have no negative impact on oil and gas operations, either now or in the future.

“Its thoroughness and our unique experience mean that the atlas is likely to attract attention far beyond Norway,” said Mr Moe.


Aquifers

The NPD has investigated subsurface formations filled with brine, known as aquifers, as well as oil and fields either already shut down or due to be abandoned by 2030-50.

Reservoirs where petroleum recovery could be improved through the injection of carbon dioxide have also been assessed.

The potential storage formations are evaluated against various criteria and ranked by their maturity for being used to hold the greenhouse gas.

In order to assess the storage efficiency of the formations, moreover, the NPD has conducted reservoir simulations for a number of the relevant areas.

The geological structures regarded as most secure and efficient could hold 1.1 gigatonnes of carbon dioxide, corresponding to annual Norwegian emissions for 20 years.

“We’ve felt that the mapped areas had a big potential, and that’s now been confirmed,” says Eva Halland, project manager for the atlas.

Knowledge of reservoir properties, cap rocks, migration routes, capacity and monitoring methods has been crucial in determining whether potential stores are suited to carbon storage over long periods, she explains.

Work on analysing reservoirs began two years ago, and the atlas is based on data from seismic surveys along with well and production information yielded by North Sea oil operations.

The project team has compared and reinterpreted data held by the NPD for up to 40 years. Governments in other countries lack such large volumes of information with a similar level of detail, Ms Halland observes.

Norway is also the only country in the world which currently stores carbon dioxide beneath the seabed, she adds, and says the country has a lot of storage sites.

Assuming that international regulations permit, it could thereby be interesting for other countries to store their carbon emissions on the NCS in the future.

Offering such storage may accordingly represent a new business opportunities for the petroleum industry.

 

The pyramid shows how the carbon stores are distributed in terms of maturity and storage capacity


The pyramid shows how the carbon stores are distributed in terms of maturity and storage capacity. One gigatonne (Gt) = one billion tonnes.

 

A conceptual sketch showing the various storage formations, and how sand has been deposited.

A conceptual sketch showing the various storage formations, and how sand has been deposited.

 

Understanding

Work on the atlas has provided a better understanding of continental shelf areas close to the Norwegian coast, says Ms Halland.

It has also given more information on the Utsira and Skade formations, the largest mapped aquifer in the North Sea. About 650 kilometres long, it could hold some 16 billion tonnes of carbon dioxide.

“There’s a big potential in these formations, but more detailed studies will be required,” Ms Halland notes. That work is now under way.

Since the goal is that the atlas will eventually cover the whole NCS, the NPD will be continuing its mapping work during 2012.

The atlas will be used in connection with invitations to apply and consideration of applications for storing carbon dioxide.

Five areas were nominated this autumn as suitable for future storage from the planned full-scale carbon capture plant at the Mongstad industrial complex north of Bergen.

Regulations for carbon transport and storage on the NCS are currently under development.


Bound copy

Read more about the atlas, which is in English, here >>

It can be downloaded free of charge, and a bound copy can also be ordered at a price of NOK 1 000.