M Rücker1, W-B Bartels2, G Garfi3, M Shams3, T Bultreys4, M Boone5, S Pieterse6, G C Maitland7, S Krevor3, V Cnudde8, H Mahani6, S Berg9, A Georgiadis10, P F Luckham7. 1. Chemical Engineering, Imperial College London, SW7 2AZ, UK; Shell Global Solutions International B.V., 2288 GS Rijswijk, Netherlands. Electronic address: m.rucker15@imperial.ac.uk. 2. Shell Global Solutions International B.V., 2288 GS Rijswijk, Netherlands; Earth Sciences Department, Utrecht University, 3584 CD Utrecht, Netherlands. 3. Earth Science and Engineering, Imperial College London, SW7 2AZ, UK. 4. Chemical Engineering, Imperial College London, SW7 2AZ, UK; UGCT-PProGRess, Ghent University, Krijgslaan 281 S8, 9000 Ghent, Belgium. 5. TESCAN XRE, Bollenbergen 2B Bus 1, 9052 Gent, Belgium. 6. Shell Global Solutions International B.V., 2288 GS Rijswijk, Netherlands. 7. Chemical Engineering, Imperial College London, SW7 2AZ, UK. 8. UGCT-PProGRess, Ghent University, Krijgslaan 281 S8, 9000 Ghent, Belgium; Earth Sciences Department, Utrecht University, 3584 CD Utrecht, Netherlands. 9. Chemical Engineering, Imperial College London, SW7 2AZ, UK; Shell Global Solutions International B.V., 2288 GS Rijswijk, Netherlands; Earth Science and Engineering, Imperial College London, SW7 2AZ, UK. 10. Chemical Engineering, Imperial College London, SW7 2AZ, UK; Shell Global Solutions International B.V., 2288 GS Rijswijk, Netherlands.
Abstract
HYPOTHESIS: The wetting behaviour is a key property of a porous medium that controls hydraulic conductivity in multiphase flow. While many porous materials, such as hydrocarbon reservoir rocks, are initially wetted by the aqueous phase, surface active components within the non-wetting phase can alter the wetting state of the solid. Close to the saturation endpoints wetting phase fluid films of nanometre thickness impact the wetting alteration process. The properties of these films depend on the chemical characteristics of the system. Here we demonstrate that surface texture can be equally important and introduce a novel workflow to characterize the wetting state of a porous medium. EXPERIMENTS: We investigated the formation of fluid films along a rock surface imaged with atomic force microscopy using ζ-potential measurements and a computational model for drainage. The results were compared to spontaneous imbibition test to link sub-pore-scale and core-scale wetting characteristics of the rock. FINDINGS: The results show a dependency between surface coverage by oil, which controls the wetting alteration, and the macroscopic wetting response. The surface-area coverage is dependent on the capillary pressure applied during primary drainage. Close to the saturation endpoint, where the change in saturation was minor, the oil-solid contact changed more than 80%.
HYPOTHESIS: The wetting behaviour is a key property of a porous medium that controls hydraulic conductivity in multiphase flow. While many porous materials, such as hydrocarbon reservoir rocks, are initially wetted by the aqueous phase, surface active components within the non-wetting phase can alter the wetting state of the solid. Close to the saturation endpoints wetting phase fluid films of nanometre thickness impact the wetting alteration process. The properties of these films depend on the chemical characteristics of the system. Here we demonstrate that surface texture can be equally important and introduce a novel workflow to characterize the wetting state of a porous medium. EXPERIMENTS: We investigated the formation of fluid films along a rock surface imaged with atomic force microscopy using ζ-potential measurements and a computational model for drainage. The results were compared to spontaneous imbibition test to link sub-pore-scale and core-scale wetting characteristics of the rock. FINDINGS: The results show a dependency between surface coverage by oil, which controls the wetting alteration, and the macroscopic wetting response. The surface-area coverage is dependent on the capillary pressure applied during primary drainage. Close to the saturation endpoint, where the change in saturation was minor, the oil-solid contact changed more than 80%.