Events

Speaker:
Anna Herring, PhD, ARC DECRA Postdoctoral Fellow, Australian National University

Title:
Evolution of Bentheimer Sandstone Wettability During Cyclic scCO2-Brine Injections

Abstract:
Geologic sequestration in sedimentary formations has been identified as a potential technology to prevent climate-change-inducing carbon dioxide (CO2) from being emitted to the atmosphere. Achieving safe and effective storage underground requires accurate understanding and predictions of supercritical CO2 (scCO2) behavior in subsurface rock formations, including quantifying how much scCO2 is trapped within pore spaces by capillarity (vs. how much remains mobile), and constraining the occurrence of physio-chemical reactions between scCO2 and the mineral matrix. Experiments where multiple cycles of scCO2 and brine are injected into rock samples have produced conflicting results regarding the consistency of trapping as cycles progress, likely due to differences in experimental conditions and setups. We present a new set of experiments, replicating the conditions of a previous study, but with a new experimental design, apparatus and timeline. We confirm previous results that demonstrated shifts in injection pressure and scCO2 trapping behavior over multiple injection cycles, and we conduct additional analyses to discern the fluid-fluid macroscopic contact angle, interface mean and Gaussian curvatures, scCO2 interfacial area, and topology of trapped scCO2 ganglia. The results indicate that this system undergoes a transition to a “patchy” mixed-wet state, and we observe that this wettability alteration renders scCO2 more stable in the rock pore space, increasing capillary trapping over four injection cycles.

Bio:

Dr. Herring completed her PhD in Environmental Engineering from Oregon State University in 2015, and since then has been a post-doc and Australian Research Council DECRA fellow in the Department of Applied Maths at the Australian National University. She focuses on microscale physics in fluid-porous media systems and topological analysis of 3D imaged data, with applications in CO2 storage and CO2 utilization. She has recently returned to the USA, where she currently maintains a role as a visiting research fellow to the ANU.

Location:
Zoom

Contact:
Tracey Wilson