Transp Porous Med (2015) 110:157–169 DOI 10.1007/s11242-015-0563-0 A Sensitivity Study of the Effect of Image Resolution on Predicted Petrophysical Properties Nayef Alyafei 1 · Ali Qaseminejad Raeini 1 · Adriana Paluszny 1 · Martin J. Blunt 1 Received: 3 June 2014 / Accepted: 6 August 2015 / Published online: 1 September 2015 © Springer Science+Business Media Dordrecht 2015 Abstract Micro-CT scanning is a nondestructive technique that can provide three- dimensional images of rock pore structure at a resolution of a few microns. We compute petrophysical properties on three-dimensional images of benchmark rocks: two sandstones (Berea and Doddington) and two limestones (Estaillades and Ketton). We take scans at a voxel size of approximately 2.7 μm and with 1024 3 voxels for both sandstone and lime- stone rocks. We numerically upscale the images to image sizes of 512 3 , 256 3 and 128 3 , representing voxel sizes of around 5.4, 10.8, and 21.6 μm respectively, covering the same domains with coarser resolution. We calculate porosity and permeability on these images by using direct simulation and by extracting geometrical equivalent networks. We find that the predicted porosity is fairly insensitive to resolution for sandstones studied with the selected range of resolutions but sensitive for limestones with lower porosity for larger voxel sizes. For the permeability predictions, we do not observe a clear trend in permeability as a func- tion of voxel size; however, sandstones, roughly, have comparable permeability regardless of the voxel size. On the other hand, for limestones, we generally see a decreasing trend in permeability as a function of upscaled voxel size. Keywords Pore-scale modeling · Image resolution · Petrophysics · Micro-CT · Upscaling 1 Introduction Advances in three-dimensional digital imaging have allowed direct visualization of the pore space of many rocks (Dunsmuir et al. 1991; Lindquist and Venkatarangan 1999; Thovert et al. 2001; Wildenschild et al. 2002, 2005; Wildenschild and Sheppard 2013). Pore-scale imaging and modeling has received enormous attention in recent years, since it offers the promise to predict flow and transport properties using three-dimensional images of the pore space (see, B Nayef Alyafei nmalyafei@gmail.com; nayef.alyafei@qatar.tamu.edu 1 Department of Earth Science and Engineering, Imperial College London, London SW7 2AZ, UK 123