Brine-CO2 interfacial tensions (IFT) and contact angles (CA) with solid surface under geological carbon storage conditions directly impact the mobility and trapping of supercritical CO2 injected in subsurface geologic formations as part of Carbon Capture and Sequestration (CCS) technologies, an important approach to reducing anthropogenic CO2 emissions. However, published experimental data on these properties vary widely, and the fundamental basis of this variability remains unexplained. Molecular dynamics (MD) simulations have shown significant promise in elucidating IFT and CA at the nanoscale and have been able to predict trends with respect to changes in temperature and pressure. An important knowledge gap in CCS is the influence of organic residues naturally present in sedimentary rocks on brine-CO2-solid wetting and multiphase flow. Here, we carry out a series of MD simulations to probe IFTs in the presence of organic molecules. Using small organic molecules as proxies, we simulate a CO2 bubble in a water-filled 6.6 nm quartz nanopore with varying fluid pressures. We find that minor amounts of organic compounds significantly influence brine-CO2 wetting behavior.

Impact of small organic molecules on the wettability of quartz by brine versus CO2

255th National Meeting (2018)

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