The next Postgraduate Open Day will be held on Friday 22 November, 2013. Find out more and register online.
Activities within the school which may be of wider interest.
One of a number of options available to mitigate the effects of man made CO2 on climate is the burial of emissions from power stations and other industrial sources. But how safe and how efficient is burial? The design and long-term viability of a CO2 storage critically depends on how and where the CO2 is stored.
Naturally-occurring carbon dioxide can be trapped in two ways. The gas can dissolve in underground water - like bottled sparkling water. It can also react with minerals in rock to form new carbonate minerals, essentially locking away the carbon dioxide underground.
Previous research in this area used computer models to simulate the injection of carbon dioxide into underground reservoirs in gas or oil fields to work out where the gas is likely to be stored. Some models predict that the carbon dioxide would react with rock minerals to form new carbonate minerals, while others suggest that the gas dissolves into the water. Real studies to support either of these predictions have, until now, been missing.
To find out exactly how the carbon dioxide is stored in natural gas fields, the researchers uniquely combined two specialised techniques. They measured the ratios of the stable isotopes of carbon dioxide and noble gases like helium and neon in nine gas fields in North America, China and Europe. These gas fields were naturally filled with carbon dioxide thousands or millions of years ago.
They found that underground water is the major carbon dioxide sink in these gas fields and has been for millions of years.
Dr Stuart Gilfillan, the lead researcher who completed the project at the University of Edinburgh said: "We've turned the old technique of using computer models on its head and looked at natural carbon dioxide gas fields which have trapped carbon dioxide for a very long time."
"By combining two techniques, we've been able to identify exactly where the carbon dioxide is being stored for the first time. We already know that oil and gas have been stored safely in oil and gas fields over millions of years. Our study clearly shows that the carbon dioxide has been stored naturally and safely in underground water in these fields." This suggests that models of long-term storage of CO2 waste in similar geological systems need to factor in the potential mobility of CO2 dissolved in water.Nature 2nd April 2009 Letter p. 614; News & Views p. 583
The cover shows Chaffin Ranch CO2 geyser, Utah, which began erupting when a water-well was drilled into a saturated aquifer in the 1930s; the 2-cm jubilee clip, centre right, gives the scale.See Also:
This article was published on Oct 22, 2013