The MIT model predicts how much a plume of CO2 will migrate from its injection well and the path it is likely to take due to underground slopes and groundwater flow.
"A lot of people have done studies at small scales," Szulczewski said. "If we're going to offset emissions, however, we're going to inject a lot of CO2 into the subsurface. This requires thinking at the basin scale."
"Despite the fact that our model applies at the basin scale, it is very simple. Using only pen and paper, you take geological parameters such as porosity, temperature and pressure to calculate storage capacity," Szulczewski said. "Other methods suffer from major shortcomings of accuracy, complexity or scale."
Juanes studies a phenomenon called capillary trapping, through which CO2, liquefied by the pressure of the Earth, is trapped as small blobs in the briny water (picture bubbles of oil in vinegar). The CO2 dispersed throughout the basin's structural pores eventually dissolves and reacts with reservoir rocks to precipitate out into harmless carbonate minerals.
CO2 has been sequestered in small pilot projects in Norway, Algeria and elsewhere. In 2004, 1,600 tons of CO2 were injected 1,500 meters into high-permeability brine-bearing sandstone of the Frio formation beneath the Gulf coast of Texas. Current proposals call for injecting billions of tons within the continental United States.
|Contact: Elizabeth Thomson|
Massachusetts Institute of Technology