T73 Carbon and Hydrogen Storage in Geologic Systems

Monday, 16 October 2023
8:00 AM - 12:00 PM
310 / 311

DAWSONITE TRAPPING: AN OVERLOOKED TEMPORARY BUT EFFECTIVE MECHANISM FOR GEOLOGIC CARBON STORAGE?

Paper number: T73-3
Program: Technical Sessions
Time: 8:20 AM – 8:35 AM

Authors

Abstract

Mineral trapping is recognized as the most secure carbon capture and storage (CCS) mechanism to ensure the long-term retention of carbon dioxide following its injection into permeable porous geologic formations. This process can immobilize CO2 as carbonate minerals, typically as calcite, dolomite, ankerite, and siderite. Under some natural conditions, however, dawsonite (NaAl(OH)2CO3) is also stabilized, sometimes attaining significant volume fractions (VF) over 0.2 in some sedimentary formations that may originally have been rich in sodic feldspars.

In this study, we used a dawsonite-rich (~10%) CO2 gas reservoir in the Hailar basin in northern China as a natural analogue of a CO2 storage site, along with 2D reactive transport modelling, to demonstrate that a large amount of dawsonite can be generated in sandstone formations, provided sufficient Na-rich feldspar and CO2 gas are available. Modelling results show that dawsonite mineral trapping is thermodynamically favoured in the Hailar basin. While precipitated dawsonite can be preserved only in a hydrodynamically-closed system in the long term under high CO2 fugacity and high Na activities in solution, short-term trapping of CO2 in dawsonite (on the order of 10 kyr) is possible and lowers CO2 pressure, which mitigates the risk of CO2 premature leakage to the ground surface or overlying drinking water aquifers. The progressive dissipation of the gas phase CO2 over time is therefore in part controlled by the re-dissolution of dawsonite. Consideration of reservoirs or saline aquifers favourable for dawsonite formation, significantly increases the number of potential CCS sites globally. Alternating water-and-gas injection regimens could further enhance the precipitation of dawsonite in Na-rich aquifers.

Geological Society of America Abstracts with Programs. Vol. 55, No. 6

doi: 10.1130/abs/2023AM-388901

© Copyright 2023 The Geological Society of America (GSA), all rights reserved. Permission is hereby granted to the author(s) of this abstract to reproduce and distribute it freely, for noncommercial purposes. Permission is hereby granted to any individual scientist to download a single copy of this electronic file and reproduce up to 20 paper copies for noncommercial purposes advancing science and education, including classroom use, providing all reproductions include the complete content shown here, including the author information. All other forms of reproduction and/or transmittal are prohibited without written permission from GSA Copyright Permissions.