Variation of CO2-Brine Contact Angles on Natural Rocks of Different Compositions

Contact angles were measured for CO<sub>2</sub>-brine interactions on 20 different rocks that represent the properties of various CO<sub>2</sub> storage depositional environments to characterize wettability during geologic carbon storage. Three phases (gaseous, liquid, and supercritical) considered investigate effect pressure temperature. Bubbles studied in two groups larger smaller than 500 μm, latter being more relevant pore scale. Variation was observed among contact angle measurements, even while controlling sample preparation cleanliness. The variations could mainly be attributed natural heterogeneity, as shown by an increased range values smallest bubbles studied. Despite these variations, analysis 1139 measurements samples under 3 experimental conditions showed 92.8% below 40°, meaning primarily strongly-to-moderately water-wet with average 22°. 10% supercritical between 40° 60°. This constitutes 5% 4% liquid gaseous conditions, respectively. Therefore, wetting or CO<sub>2</sub></span><span>.