X-rays and Tricycles

Our research looks at supercritical CO2 and saltwater flow processes in sandstone rock cores- this helps us to understand and design geologic CO2 sequestration projects. Geologic CO2 sequestration is a climate change mitigation strategy; the idea is that we can limit carbon emissions to the atmosphere by capturing and isolating carbon dioxide (CO2) from the smoke stacks of fossil fuel power plants, and pump the CO2 underground instead of letting it out into the atmosphere. This would allow us to continue to use fossil fuels for energy (for example, coal) without contributing to climate change.

My research looks specifically at how supercritical CO2 (i.e. a superdense CO2 fluid, at high pressure [1200 PSI] and moderate temperature [40 degrees C]) moves through the pore space of sandstone. We are trying to determine if CO2 can be safely and efficiently trapped inside the pores of the rocks by capillary forces. In order to "see" inside our rock cores, we use x-ray computed microtomography. And, in order to get high flux, high quality x-rays, we need to travel to a particle accelerator and conduct our experiments at a beamline.

We only get three opportunities a year to do beamtime experiments- which makes these experiments high stress and high consequence. This round, we got 88 hours of beamtime- 88 hours of continuous supercritical experiments.

Check out some of our work on CO2 sequestration:

Herring, A.L., A.P. Sheppard, L. Andersson, and D. Wildenschild, 2015. Impact of Wettability Alteration on Three Dimensional Nonwetting Phase Trapping and Transport, Submitted, Geophysical Research Letters.

Kimbrel, E.J., A.L. Herring, R.T. Armstrong, I. Lunati, B.K. Bay, and D. Wildenschild, 2015.  On the Optimization of Capillary Trapping during Geologic CO2 Sequestration. Under revision - Intl. J. of Greenhouse Gas Control.

Herring, A.L., L. Andersson, S. Schlüter, A.P. Sheppard, and D. Wildenschild, 2015. Efficiently Engineering Pore-Scale Processes: The Role of Force Dominance and Topology during Nonwetting Phase Trapping in Porous Media, Advances in Water Resources, 79, 91–102 (2015), doi: http://dx.doi.org/10.1016/j.advwatres.2015.02.005

Herring, A.L., L. Andersson, D. Newell, J.W. Carey, and D. Wildenschild, 2014. Pore-scale observations of supercritical CO2 drainage in Bentheimer sandstone by synchrotron x-ray imaging. Intl. J. of Greenhouse Gas Control, 25 (2014) 93–101.

Herring, A.L., E.J. Harper, L. Andersson, A.P. Sheppard, B.K. Bay, and D. Wildenschild, 2013. Effect of Fluid Topology on Residual Nonwetting Phase Trapping: Implications for CO2 Sequestration. Advances in Water Resources, http://dx.doi.org/10.1016/j.advwatres.2013.09.015.