Roman Makhnenko is an assistant professor in the Department of Civil and Environmental Engineering at the University of Illinois at Urbana-Champaign. Roman has a background in mechanics and applied mathematics and he obtained his MS (2009) and PhD (2013) degrees in geological and civil engineering from the University of Minnesota – Twin Cities. From 2013 to 2016, Dr. Makhnenko worked as a postdoctoral researcher and lecturer at the Swiss Federal Institute of Technology in Lausanne (EPFL, Switzerland) on the project related to assessment of geological storage of CO 2 . Currently, Roman is developing a rock mechanics program at Illinois that includes modern high- pressure/high-temperature rock testing facilities and new graduate and undergraduate courses on the topic. His group is working on the geomechanical testing and modeling for geo-energy projects such as CO 2 and H 2 storage and shallow geothermal systems.
Tight shale-like formations are often considered as barriers for fluid flow in geo-energy projects, such as CO 2 and H 2 storage or deep disposal of nuclear waste. The appropriate shale formations should have high clay content and dominant pore sizes on the order of nanometers. Their sealing capacity is determined by high non wetting fluid entry values, low permeability, high ductility, and it varies with physical, thermal, and chemical disturbances over time. The characterization of the hydro mechanical behavior of shales is involved even when saturated with just one fluid because of very long experimental times and high sensitivity to environmental factors such as temperature or pore fluid chemistry. The unsaturated poromechanical properties are even more difficult to be measured since the solid, pore, and fluid compressibility cannot be neglected and the degree of saturation should be controlled. In this study, the results of a comprehensive laboratory characterization of a few shale-like materials with different porosity, permeability, and dominant grain and pore sizes are discussed. The effect of mineral composition and presence of heterogeneities, including fractures, on sealing capacity of shales is investigated under varying effective mean stress, pore pressure, and temperature. The implications of using these shales as barriers for advective and channeled fluid flow, including CO 2 injection, are presented for the representative in-situ conditions.