Experimental studies of supercritical CO2 dissolution and its influence on drainage and imbibition using pore-scale micromodels
EMSL Project ID
48255
Abstract
The characteristics of two-phase flow of supercritical CO2 (scCO2) injected into deep saline aquifers and brine (e.g., relative permeability and residual saturation) and scCO2 dissolution are of great importance to CO2 injectivity, storage efficiency, and storage security in geological CO2 storage. Previous core- and pore-scale flood experiments showed that scCO2-water drainage and imbibition and scCO2 dissolution interplay with each other, under the significant impact of sub-core and pore-scale heterogeneity. Various causes of the "lumped" effect of dissolution on drainage and imbibition were inferred from comparative experiments. However, pore-scale study is the only way to provide direct evidences to pore-scale processes and interactions between dissolution and displacement. We propose here to use the advanced facility at the Environmental Molecular Sciences Laboratory (EMSL) to fabricate two-dimensional pore-scale micromodels and to conduct four different sets of experiments in these micromodels. The main objective is to study (equilibrium, non-equilibrium, and convection-enhanced) scCO2 dissolution and its influence on displacement during drainage and imbibition in homogeneous, heterogeneous, and layered micromodels. Injected scCO2 will be fluorescein-dyed to improve the imaging analysis of free-phase scCO2-water configurations, while injected water or water initially occupying the micromodels before drainage will be mixed with bromocresol green (a pH indicator) to measure spatially-varying concentration of dissolved CO2 in water. Specifically, we will (1) investigate the scCO2 dissolution and its effect on drainage and imbibition by imaging the dissolution process and by comparing the displacement (including two-phase relative permeability and saturation) with dissolution to that without dissolution, (2) investigate the dissolution of residual scCO2 and creation of new water flow paths for enhanced CO2 dissolution in both homogeneous and heterogeneous micromodels (relative to dissolution trapping at the tail of a CO2 plume), and (3) image the flow-dissolution-convection process and investigate the triggering and evolution of convective fingers and convection-enhanced dissolution using a layered micromodel. Results from these proposed micromodel studies will help elucidate CO2 trapping and dissolution mechanisms at pore scale, and explain the scCO2-water displacement behavior at sub-core and core scale, even at basin scale. The success of these studies can also deepen our fundamental understanding of two-phase flow in porous media in other fields, such as oil recovery and contamination remediation.
Project Details
Project type
Exploratory Research
Start Date
2014-02-17
End Date
2015-03-31
Status
Closed
Released Data Link
Team
Principal Investigator
Related Publications
Chang C, Q Zhou, M Oostrom, T Kneafsey, and HS Mehta. 2017. "Pore-scale Supercritical CO2 Dissolution and Mass Transfer under Drainage Conditions." Advances in Water Resources 100:14-25. doi:10.1016/j.advwatres.2016.12.003
Chang C., Q. Zhou, T.J. Kneafsey, M. Oostrom, and Y. Ju. 2019. "Coupled supercritical CO2 dissolution and water flow in pore-scale micromodels." Advances in Water Resources 123. PNNL-SA-152825. doi:10.1016/j.advwatres.2018.11.004
Chang C, Q Zhou, TJ Kneafsey, M Oostrom, TW Wietsma, and Q Yu. 2016. "Pore-Scale Supercritical CO2 Dissolution and Mass Transfer under Imbibition Conditions." Advances in Water Resources 92:142-158. doi:10.1016/j.advwatres.2016.03.015
Chang C., T.J. Kneafsey, Q. Zhou, M. Oostrom, and Y. Ju. 2019. "Scaling the impacts of pore-scale characteristics on unstable supercritical CO2-water drainage using a complete capillary number." International Journal of Greenhouse Gas Control 86. PNNL-SA-152826. doi:10.1016/j.ijggc.2019.04.010
NCGC seminar at Lawrence Berkeley National Laboratory