Abstract

Geological storage of CO₂ (GCS), also referred to as carbon sequestration, is a critical component for decreasing anthropogenic CO₂ atmospheric emissions. Stored CO₂ will exist as a supercritical phase, most likely in deep, saline, sedimentary reservoirs. Research at the Center for Frontiers of Subsurface Energy Security (CFSES), a Department of Energy, Energy Frontier Research Center, provides insights into the storage process. The integration of pore-scale experiments, molecular dynamics simulations, and study of natural analogue sites has enabled understanding of the efficacy of capillary, solubility, and dissolution trapping of CO₂ for GCS. Molecular dynamics simulations provide insight on relative wetting of supercritical CO₂ and brine hydrophilic and hydrophobic basal surfaces of kaolinite. Column experiments of successive supercritical CO₂/brine flooding with high-resolution X-ray computed tomography imaging show a greater than 10% difference of residual trapping of CO₂ in hydrophobic media compared to hydrophilic media that trapped only 2% of the CO₂. Simulation results suggest that injecting a slug of nanoparticle dispersion into the storage reservoir before starting CO₂ injection could increase the overall efficiency of large-scale storage. We estimate that approximately 22% ± 17% of the initial CO₂ emplaced into the Bravo Dome field site of New Mexico has dissolved into the underlying brine. The rate of CO₂ dissolution may be considered limited over geological timescales. Field observations at the Little Grand Wash fault in Utah suggest that calcite precipitation results in shifts in preferential flow paths of the upward migrating CO₂-saturated-brine. Results of hybrid pore-scale and pore network modeling based on Little Grand Wash fault observations demonstrate that inclusion of realistic pore configurations, flow and transport physics, and geochemistry are needed to enhance our fundamental mechanistic explanations of how calcite precipitation alters flow paths by pore plugging to match the Little Grand Wash fault observations.

Department(s)

Civil, Architectural and Environmental Engineering

Comments

This material is based upon work supported as part of the Center for Frontiers of Subsurface Energy Security, an Energy Frontier Research Center funded by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under Award Number DE-SC0001114.

Keywords and Phrases

Calcite; Dissolution; Experiments; Faulting; Forestry; Groundwater flow; Hydrophilicity; Hydrophobicity; Kaolinite; Molecular dynamics; Physics; Calcite precipitation; Geological Timescales; High-resolution X-ray computed tomographies; Hydrophilic and hydrophobic; Molecular dynamics simulations; Nano-particle dispersions; Pore-network modeling; Sedimentary reservoirs; Carbon dioxide

International Standard Serial Number (ISSN)

1932-7447

Document Type

Article - Journal

Document Version

Final Version

File Type

text

Language(s)

English

Rights

© 2014 American Chemical Society (ACS), All rights reserved.

Share

 
COinS