[HSC07-P06] Derivation of contact angle for evaluation of caprock’s sealing performance
Keywords:Geological CO2 storage, Contact angle, Sealing performance, Threshold pressure, Caprock
The target samples are five kinds of minerals (quartz, albite, chlorite, calcite, and gypsum) and two types of rocks (malrite and mudstone). These samples were available for breakthrough experiments of supercritical CO2 at 10 MPa and 40°C. Then, θ was calculated using measured Pcth. Results showed that our method enabled to derive θ in a reproducible fashion. However, some samples led to cosθ > 1, in which the θ cannot be defined. Such an inconsistency is caused by the high sensitivity of σ to θ. Therefore, we should examine more accurate data of σ, hereafter. In either case, we can estimate the magnitude relationship of each sample’s θ from calculated cosθ. The study revealed that silicate minerals such as quartz, albite and chlorite, and rocks mainly composed of clay minerals such as marlite and mudstones had a wetting surface (i.e., low θ). In contrast, both calcite as a carbonate mineral and gypsum as a sulfate mineral showed a relatively non-wetting surface (i.e., high θ).