CEE Seminar: Hydro-chemo-mechanical Coupling in Fine-grained Soils and Sedimentary Rocks

Abstract: A recurrent theme in the use of the subsurface for water, energy or carbon mitigation is the importance of fine-grained (clay-rich) soils and sedimentary rocks. Fine-grained rocks are used as caprocks, host rocks and source rocks in a range of low-carbon energy technologies including carbon capture and storage and high-level radioactive waste storage. Fine-grained soils play an outsize role in agriculture and soil carbon storage. This importance of clay-rich media derives largely from their distinct hydrologic and mechanical properties (ultra-low permeability, swelling-shrinking and cracking). Here, we discuss existing data in the hydrologic and mechanical properties of fine-grained sedimentary rocks. We show that these properties are controlled by chemo-mechanical-chemical couplings at two key scales: a mesoscale defined by the assemblage of coarse grains and a nanoscale defined by the aggregation and swelling of clay nanoparticles. We present recent advances in modeling clay-rich media on these two length scales using computational fluid dynamics and molecular dynamics simulations.

Bio: Ian Bourg is an assistant professor in civil and environmental engineering at Princeton University. His group studies the properties of water at interfaces, with a particular emphasis on the impact of clay minerals on hydrology, mechanics and geochemistry of soils and sedimentary media. He obtained his doctorate in civil and environmental engineering from UC Berkeley in 2004 and served as a scientist at the Lawrence Berkeley National Laboratory until 2014 before joining the faculty at Princeton University.