title: Impact of wettability on pore-scale characteristics of residual nonaqueous phase liquids.
abstract: The objective of this paper was to investigate the impact of wettability of porous media on pore-scale characteristics of residual nonaqueous phase liquids (NAPLs). Synchrotron X-ray microtomography was used to obtain high-resolution three-dimensional images of fractionally wet sand systems with mean grain size of 250 microm. Pore-scale characteristics of NAPL blobs such as volume, lengths, interfacial areas, and sphericity index were computed using three-dimensional image processing algorithms. Four systems comprised of 100, 50, 25, and 0% NAPL-wet mass fractions containing the residual NAPL were imaged and analyzed. Findings indicate that spatial variation in wettability of porous media surfaces has a significant impact on pore-scale characteristics of residual NAPL blobs in saturated porous media systems. As the porous media comprises more water-wet surfaces, residual NAPL blobs increase in size and length due to the entrapment at large pore bodies. NAPL-water interfacial areas tend to increase as the NAPL-wet surface fractions increase in the systems. Overall residual NAPL saturations are less in fractionally wet systems and increase as the systems become more NAPL-wet or water-wet.
authors: Department of Civil and Environmental Engineering, Southern University and A&M College Baton Rouge, Louisiana 70813, USA. riyadh@engr.subr.edu
authors: Riyadh I
authors: RI
authors: Al-Raoush
mesh_terms: D000465:Algorithms; D004784:Environmental Monitoring / Q000379:methods*; D004785:Environmental Pollutants / Q000032:analysis*; D007091:Image Processing, Computer-Assisted; D015233:Models, Statistical; D010316:Particle Size; D016062:Porosity; D017356:Synchrotrons; D014056:Tomography, X-Ray / Q000379:methods; D014867:Water / Q000737:chemistry; D017155:Wettability
chemical_list: D004785:Environmental Pollutants; D014867:Water