Page 3 of 4Global CCS development
But CCS is more than just an experimental technology and is now active in various guises at several flagship fields around the world, including Africa.
At one of Algeria’s biggest natural gas fields, In Salah, operator BP has a system to re-inject CO2 into deep wells, which significantly reduces overall GHG emissions. To avoid venting the gas into the atmosphere, BP and its partners, Sonatrach and Statoil, recruited engineers from JGC and KBR to design CO2 capture facilities, which then inject CO2 into a brine formation approximately one mile below the surface.
In Europe, Statoil has played a similarly pioneering role in the deployment of CCS technology in its home Norwegian market. The company has even produced a comprehensive ‘carbon road map’ – a detailed compendium of carbon dioxide sources, transport mechanisms and long-term storage initiatives. One of Statoil’s flagship CCS initiatives is at Western Europe’s only liquefied natural gas (LNG) plant, which takes its gas from the Snøhvit field in the Barents Sea.
The Snøhvit gas contains 5-6 per cent CO2 which freezes to solid matter (so-called CO2 ice) at a higher temperature than natural gas. It must therefore be removed before the gas is cooled into LNG.
Moreover, the carbon dioxide also has to be separated from the hydrocarbons at a sufficiently early stage in the process, so that the gas mixture does not freeze and block the heat exchangers in the processing plant. A separate pipeline transports the carbon dioxide from the Hammerfest LNG plant back to the Snøhvit field.
There, it is stored in a suitable geological layer of porous sandstone called the Tubåen formation. This structure lies 2,500 metres beneath the seabed and under the layers in Snøhvit containing gas. More than 700,000 tonnes of carbon dioxide are to be stored annually at the site.
A separate monitoring programme has also been established, which is being part-funded by the EU, to examine how the carbon dioxide behaves in the reservoir.
The carbon challenge
Africa has a fight on its hands rising to the challenge of carbon management but the technology to do it is maturing fast - Image credit to str8talkchronicle.com
