Mechanisms for kerogen wettability transition from water-wet to CO2-wet: Implications for CO2 sequestration

• As CO 2 pressure increases, kerogen wettability shifts from H O-wet to -wet. crowding near surface at high pressures leads the -wet state. Carbon skeleton favors , resulting in a film formed O-kerogen interface. Geological sequestration (GCS) is an essential building block of global strategy alleviate greenhouse gas emissions and mitigate climate change. Injecting into shale formations can not only reduce carbon but also enhance oil recovery (EOR). Rock great importance storage as it determines efficiency structural residual trapping plays crucial role -EOR. In this work, molecular dynamics (MD) simulations are adopted investigate -H systems under various pressures. vacuum or low pressures, weakly water-wet thanks hydrogen bonding between O kerogen. -wet, because more molecules accumulate interface distinct thin emerges. Density functional theory (DFT) calculations reveal that O-containing groups preferably adsorb over through bonding, which responsible for tendency contrast, exhibits stronger affinity leading formation on surface. The close gives rise This study provides, first time, fundamental mechanism transition work indicates mature likely be during GCS, unfavorable capillary favorable