Carbon dioxide can be safely stored in porous sandstone of former oil fields
University of Leeds
November 28, 2007
EDITOR SUMMARY: New research suggests that carbon dioxide can be safely geosequestered in porous sandstone that formely contained oil. The findings may help scientists devise alternative mechanisms for fighting global warming.
University of Leeds research shows that porous sandstone, drained of oil by the energy giants, could provide a safe reservoir for carbon dioxide. The study found that sandstone reacts with injected fluids more quickly than had been predicted - such reactions are essential if the captured CO2 is not to leak back to the surface.
The study looked at data from the Miller oilfield in the North Sea, where BP had been pumping seawater into the oil reservoir to enhance the flow of oil. As oil was extracted, the water that was pumped out with it was analysed and this showed that minerals had grown and dissolved as the water travelled through the field.
This image depicts a 3-day average of actual sea surface temperatures (SSTs) for the Caribbean Sea and the Atlantic Ocean, from August 25-27, 2005. Image Credit: NASA/SVS.
Carbon-negative bioenergy to cut global warming could drive deforestation
A proposed mechanism for generating carbon-negative bioenergy -- an energy source that reduces atmospheric carbon dioxide levels -- could drive large-scale deforestation in the tropics and undermine efforts to conserve forests for carbon offsets says a biofuel expert. Laurens Rademakers, a natural resource management consultant and co-founder of bioenergy research group Biopact, says that the emerging concept of coupling bioenergy production with carbon capture and storage could trigger conversion of natural forests for energy crop feedstock plantations. These plantations would not only produce income from energy production but would generate carbon credits for sequestering atmospheric carbon dioxide.
Giant carbon sequestration project begins in Australia
The largest carbon burial experiment in the world got underway yesterday in Australia with the drilling of a 2100-meter (6825 meter) well in the Otway Basin. If there are no signs of leaks, researchers from the Canberra-based Cooperative Research Centre for Greenhouse Gas Technologies (CO2CRC) will begin injecting carbon dioxide into the well in July according to an article from the NewScientist.com news service.
The study gives a clear indication that carbon dioxide sequestered deep underground could also react quickly with ordinary rocks to become assimilated into the deep formation water.
The work was supervised by Bruce Yardley, Professor in the School of Earth and Environment at the University, who explained: "If CO2 is injected underground we hope that it will react with the water and minerals there in order to be stabilized. That way it spreads into its local environment rather than remaining as a giant gas bubble which might ultimately seep to the surface.
"It had been thought that reaction might take place over hundreds or thousands of years, but there's a clear implication in this study that if we inject carbon dioxide into rocks, these reactions will happen quite quickly making it far less likely to escape."
Although extracting CO2 from power stations and storing it underground has been suggested as a long-term measure for tackling climate change, it has not yet been put to work for this purpose on a large scale. "There is one storage project in place at Sleipner, in the Norwegian sector of the North Sea, and some oil companies have actually used CO2 sequestration as a means of pushing out more oil from existing oilfields," said Prof Yardley.
In the UK the Prime Minister has recently announced a major expansion of energy from renewable sources and the launch of a competition to build one of the world's first carbon capture and storage plants. (3) The Leeds study suggests the technique has long-term potential for safely storing this major by-product of our power stations, rather than allowing it to escape and further contribute to global warming.
The paper "Rapid fluid-rock interaction in oilfield reservoirs" by SJ Houston, BWD Yardley, PC Smalley and I Collins is published by the Geological Society of America in the December issue of Geology. A pdf copy of the paper is available on request.