Transp Porous Med (2014) 102:71–90 DOI 10.1007/s11242-013-0262-7 Grain Shape Effects on Permeability, Formation Factor, and Capillary Pressure from Pore-Scale Modeling T. Torskaya · V. Shabro · C. Torres-Verdín · R. Salazar-Tio · A. Revil Received: 14 July 2013 / Accepted: 6 December 2013 / Published online: 20 December 2013 © Springer Science+Business Media Dordrecht 2013 Abstract We invoke pore-scale models to evaluate grain shape effects on petrophysical properties of three-dimensional (3D) images from micro-CT scans and consolidated grain packs. Four sets of grain-packs are constructed on the basis of a new sedimentary algo- rithm with the following shapes: exact angular grain shapes identified from micro-CT scans, ellipsoids fitted to angular grains, and spheres with volume and surface-to-volume ratio equal to original angular grains on a grain-by-grain basis. Subsequently, a geometry-based cementation algorithm implements pore space alteration due to diagenesis. Eight micro-CT scans and 144 grain-pack images with 500 × 500 × 500 voxels (the resolution units of 3D images) are analyzed in this study. Absolute permeability, formation factor, and cap- illary pressure are calculated for each 3D image using numerical methods and compared to available core measurements. Angular grain packs give rise to the best agreement with experimental measurements. Cement volume and its spatial distribution in the pore space significantly affect all calculated petrophysical properties. Available empirical permeability correlations for non-spherical grains underestimate permeability between 30 and 70 % for the analyzed samples. Kozeny–Carman’s predictions agree with modeled permeability for spherical grain packs but overestimate permeability for micro-CT images and non-spherical grain packs when volume-based radii are used to calculate the average grain size in a pack. T. Torskaya · V. Shabro · C. Torres-Verdín (B ) The University of Texas at Austin, Austin, TX, USA e-mail: cverdin@austin.utexas.edu T. Torskaya e-mail: taceto@utexas.edu R. Salazar-Tio Chevron Energy Technology Company, San Ramon, CA, USA A. Revil Department of Geophysics, Colorado School of Mines, Golden, CO, USA A. Revil ISTerre, UMR CNRS 5275, Université de Savoie, Le Bourget du Lac, France 123