My watch list
my.chemeurope.com  
Login  

Predicting the fate of underground carbon

25-11-2009: A team of researchers at the Massachusetts Institute of Technology has developed a new modeling methodology for determining the capacity and assessing the risks of leakage of potential underground carbon-dioxide reservoirs.

One strategy for mitigating greenhouse gases is to inject compressed carbon dioxide into natural aquifers made of permeable rock soaked with brackish salt water. Carbon dioxide is less viscous and less dense than the water, and, once injected, it rises to the top of the aquifer. The permeable rock usually lies underneath a dense, impermeable "cap rock," that traps the gas deep underground for long periods of time.

Cap rocks are often tilted, however, and as the carbon dioxide rises through the aquifer, it can slip out, eventually making its way back into the atmosphere. Engineers seek to avoid leakage by mapping potential reservoirs and using theoretical tools to predict carbon dioxide flow.

Now doctoral students Christopher MacMinn and Michael Szulczewski and Professor Ruben Juanes of the Massachusetts Institute of Technology have developed a new modeling methodology for determining the capacity of potential reservoirs and for assessing the risks of leakage.

The tool takes into account key aspects of the underlying physics to predict the shape and pattern of flow when carbon dioxide is injected into a deep underground aquifer.

"Our new modeling tool is analytical rather than numerical, which means it incorporates the three primary physical mechanisms by which carbon dioxide is trapped in briny substrate -- structural, capillary and dissolution trapping -- into a single, comprehensive mathematical expression that can be solved quickly," says MacMinn. "This makes it possible for us to alter key parameters, such as the aquifer permeability, the fluid viscosities or the tilt of the cap rock, and within seconds, predict how the plume of carbon dioxide will migrate through the subsurface."

Before, each parameter change in a numerical model added hours or days to the time it took a computer to model discrete sections of the substrate and pull all these together into a prediction of carbon dioxide behavior under those limited circumstances. Engineers would have needed to run dozens if not hundreds of these to incorporate all the likely parameter permutations, making this an infeasible means of assessment. The hope now is that engineers and geologists may be able to use this new modeling tool to quickly and inexpensively determine whether carbon dioxide would escape from a geological reservoir.

More about MIT
  • News

    Getting the salt out

    The boom in oil and gas produced through hydraulic fracturing, or fracking, is seen as a boon for meeting U.S. energy needs. But one byproduct of the process is millions of gallons of water that's much saltier than seawater, after leaching salts from rocks deep below the surface. Now resear ... more

    How to make a 'perfect' solar absorber

    The key to creating a material that would be ideal for converting solar energy to heat is tuning the material's spectrum of absorption just right: It should absorb virtually all wavelengths of light that reach Earth's surface from the sun — but not much of the rest of the spectrum, since th ... more

    Recycling old batteries into solar cells

    This could be a classic win-win solution: A system proposed by researchers at MIT recycles materials from discarded car batteries — a potential source of lead pollution — into new, long-lasting solar panels that provide emissions-free power. The system is described in a paper in the journal ... more

More about American Institute of Physics
  • News

    The future face of molecular electronics

    The emerging field of molecular electronics could take our definition of portable to the next level, enabling the construction of tiny circuits from molecular components. In these highly efficient devices, individual molecules would take on the roles currently played by comparatively-bulky ... more

    Predator-prey made simple

    A team of U.K. researchers has developed a way to dramatically reduce the complexity of modeling "bistable" systems which involve the interaction of two evolving species where one changes faster than the other ("slow-fast systems"). Described in The Journal of Chemical Physics, the work pav ... more

    Sensitive detection method may help impede illicit nuclear trafficking

    According to the International Atomic Energy Agency (IAEA) the greatest danger to nuclear security comes from terrorists acquiring sufficient quantities of plutonium or highly enriched uranium (HEU) to construct a crude nuclear explosive device. The IAEA also notes that most cases of illici ... more

Your browser is not current. Microsoft Internet Explorer 6.0 does not support some functions on Chemie.DE