Pore-scale contact angle measurements of CO2-brine-glass beads system using micro-focused X-ray computed tomography

Conventional methods for measuring contact angle are usually applied on smooth surfaces. Methods concerning contact angle determinations performed directly on pore surfaces of porous media have rarely been reported. This work approaches the pore-scale measurement of local contact angle in a CO2-brine-glass beads system, using micro-focused X-ray computed tomography (micro-CT). Both drainage and imbibition experiments with 0.1 ml/min injection rate were conducted at 40 degrees C and 8 MPa. The effectiveness of this pore-scale approach is confirmed by comparing the results with the results gathered from traditional sessile drop methodology. Observations indicate that the contact angle hysteresis phenomenon was not so obvious for intermediate-wet glass beads in the employed experimental setting. In real reservoir circumstances, the roughness and capillary variation caused significant deviations in contact angle distribution for both drainage and imbibition, even in rock cores consisting of a single-phase material.