Predicting the fate of underground carbon

Nov 23, 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. They will present their findings at the 62nd Annual Meeting of the American Physical Society's (APS) Division of will take place from November 22-24 at the Minneapolis Convention Center.

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 would escape from a geological reservoir.

More information: The presentation "Post-Injection Migration of CO2 in Saline Aquifers subject to Groundwater Flow, Aquifer Slope, and Capillary Trapping" by Christopher MacMinn, Michael Szulczewski, and Ruben Juanes of the Massachusetts Institute of Technology is at 11:48 a.m. on Monday, November 23, 2009.

Source: American Institute of Physics

Explore further: New microscope collects dynamic images of the molecules that animate life

add to favorites email to friend print save as pdf

Related Stories

Trapping Greenhouse Gases (Without Leaks)

Nov 19, 2008

Of all the possible ways of reducing future greenhouse gas emissions, one of the most immediately feasible is carbon dioxide "sequestration," which involves compressing the gas into a liquid and piping it deep underground ...

Storing CO2 below ground may prevent polluting above

Feb 07, 2007

A new analysis led by an MIT scientist describes a mechanism for capturing carbon dioxide emissions from a power plant and injecting the gas into the ground, where it would be trapped naturally as tiny bubbles and safely ...

Safe storage of greenhouse-gas carbon dioxide

Nov 17, 2008

To prevent global warming, researchers and policymakers are exploring a variety of options to significantly cut the amount of carbon dioxide that reaches the atmosphere. One possible approach involves capturing greenhouse ...

Carbon capture has a sparkling future

Apr 01, 2009

( -- New research shows that for millions of years carbon dioxide has been stored safely and naturally in underground water in gas fields saturated with the greenhouse gas. The findings - published ...

Recommended for you

Cooling with molecules

Oct 22, 2014

An international team of scientists have become the first ever researchers to successfully reach temperatures below minus 272.15 degrees Celsius – only just above absolute zero – using magnetic molecules. ...

User comments : 0