Ph.D. Thesis Defense Announcement

CO2 MINERALIZATION IN BASALTIC ROCKS

By Zhao Xia

Advisor: Dr. J. Carlos Santamarina (CEE)

Committee Members:

Dr. Haiying Huang (CEE) | Dr. Susan E. Burns (CEE)

Dr. D. Nicolas Espinoza (PGE, UT Austin) | Dr. Costas Tsouris (ORNL/CEE)

Date and Time: June 6, 2024. 8:30 AM EST

Location: Mason 2119 | Zoom: https://gatech.zoom.us/j/99933613428

ABSTRACT
Carbon geological storage by mineralization presents a promising strategy for
climate change mitigation due to its long-term stability and substantial storage
potential. The injection of CO2-saturated water triggers sequential mineral
dissolution and precipitation fronts that progressively alter rock porosity and
permeability, and modify flow pathways in a self-homogenizing mineralization
process. Eventually these coupled processes affect the injection performance,
storage capacity and reservoir stability. This study explores the intricate interplay
among mineralogy, pore structure, fluid chemistry, and the impacts of dissolutionprecipitation
on coupled fluid transport. First, we establish causal connections between basalt genesis and the ensuing pore structures, and investigate the impact
of pore structure on connectivity, permeability and accessible pore-matrix surface
area of basaltic rocks. We then identify the key minerals governing overall rock
dissolution and quantify the reactivity and CO2 mineral trapping capacity of both
basalt and basaltic sediments. Next, we study the fluid-rock interactions during
diffusive and advective transport. Sequential tomographic images and
complementary reactive-transport modeling allow us to elucidate the evolution of
fracture-matrix interaction in the near and far-field of the injection well. Different
injection strategies are assessed using a high-temperature and high-pressure
reactive flow-through device to formulate optimized injection protocols tailored to
diverse field conditions, aiming to enhance field-scale CO2 mineralization. Finally,
we explore the local controls on mineral precipitation using Marangoni flow to
mitigate near-wellbore salt accumulation during undersaturated CO2 injection. The
findings of this study support the improved assessment of mineral trapping
efficiency and reservoir storage capacity, and provide valuable insights for fluid
selection during injection with implications for site identification for carbon
geological storage.