Effect of CO2 injection on the poromechanical and multiphase flow characteristics of subsurface rock

Postdoctoral Fellow, Department of Petroleum and Geosystems Engineering, University of Texas at Austin

Geologic carbon storage has a great potential in reducing the atmospheric CO2 emission by permanently storing large volumes of carbon dioxide in reservoir formations sealed with tight rock. During CO2 injection, multi-physical processes occur, affecting the mechanical stresses, pore pressures, temperatures, and chemistry of the participating subsurface rocks and pore fluids. These processes are coupled, meaning that changes in each aspect do impact the others mutually. Thus, the interdependent factors need to be understood as a combined system, while it should also incorporate the time-dependent response, as CO2 is projected to be stored for thousands of years. Furthermore, to avoid CO2 leakage through the sealing layers, their poromechanical and hydraulic properties need to be thoroughly addressed.Experimental techniques are introduced to characterize the poroviscoelastic and hydraulic behavior, including two-phase flow, with CO2 treatment tests conducted under high-pressure conditions. Hydro-mechanical-chemical coupling constitutive model is adopted to address the chemo-poro-viscoelastic response of subsurface rock, with additional studies to explore the impact of the duration of CO2 injection. Ultra-low permeability of the sealing formations is accurately measured in a few month-long experiments and is coupled to the mechanical and pore network characteristics of the rock. In summary, this presentation provides a comprehensive experimental work aimed at characterizing the poromechanical and hydraulic response during CO2 injection, where the chemical effect is also investigated.

Kiseok Kim is a Postdoctoral Fellow in the Hildebrand Department of Petroleum and Geosystems Engineering at University of Texas at Austin. He achieved his Bachelors and Masters degree in Civil Engineering at Korea University, and obtained his Ph.D. degree in Civil Engineering from the University of Illinois at Urbana-Champaign. Dr. Kim’s research focuses on the impact of CO2 injection on the poromechanical and multiphase flow behaviors of subsurface rocks. Novel experimental methods, including Advanced Triaxial Compression System, Hydrostatic Compression Cell, and Core Flooding Device for multiphase flow injection are utilized, as well as microscale measurements using the Scanning Electron Microscope and Mercury Intrusion Porosimetry. His research is applied to various geo-energy projects, such as geothermal systems, enhanced oil recovery, and gas shale responses, and is aimed at gaining a better understanding of the multiphysical subsurface rock behavior at multiple scales.