Carbon Sequestration in Unconventional Reservoirs:
Petrophysical, Geomechanical and Geochemical Considerations
In the face of the challenges presented by the acceleration of global warming, carbon capture and storage (CCS) may provide a vital option to reduce the emissions of anthropogenic greenhouse gases and to mitigate climate change. To operate on a global scale, however, CCS would require thousands of geologic repositories that could accommodate a few billion tons of carbon dioxide (CO2) per year. In order to reach such capacity, various types of geologic reservoirs should be considered, including unconventional reservoirs such as volcanic rocks, fractured formations and moderate permeability aquifers. My research focuses on understanding petrophysical, geomenchanical and geochemical properties of such reservoirs using borehole geophysical methods collected in a variety of geologic settings, e.g. extrusive continental flood basalt (Columbia River Plateau), igneous intrusion (the Palisades Sill) and fractured aquifers in the Newark Rift Basin.
Borehole geophysics provides a set of effective techniques for formation characterization at an intermediate scale, filling the gap between large-scale surface surveys and core-scale analysis. In my research I utilize advanced borehole logging methods, such as borehole imaging, full wave sonic, and spectral geochemical logging, to improve base-line characterization techniques and explore their potential for CO2 sequestration monitoring. Among primary objectives are estimating formation porosity and permeability, and assessing caprock integrity under injection conditions; characterizing fracture distribution and their hydraulic properties; evaluating in-situ stress regime, formation geomechanical properties, and induced seismicity risks; understanding formation anisotropy; and detecting in-situ geochemical and mineral changes. Overall, my research contributes to better understanding of structural and petrophysical properties of unconventional reservoirs, and improves geophysical characterization techniques for igneous rocks and fractured formations.