We propose a generalized workflow for mineralogy investigation of unconventional reservoirs using multi-scale imaging and pore-scale analyses. This workflow can be used for the integral evaluation of these resources. It includes X-ray computed tomography to image fracture networks, identify areas of interest, and serve as a frame of reference for obtaining high-resolution images. On the other hand, it is also possible to carry out the integration of high resolution 2D images of mapping by SEM and QEMSCAN. into micro-CT data for the upscaling of the computed petrophysical properties. Digital rock physics, an important step for the integral evaluation of unconventional reservoirs, involves imaging and analysis of unconventional samples such as tight sandstones, carbonates, and shales, to determine the impact of clay minerals, and diagenetic processes on the computed petrophysical properties, such as porosity and pore space topology (e.g., pore size distribution, connectivity, and pore shapes), absolute and relative permeability, capillary pressure, and fracture network topology. In this paper, we introduce the underlying concepts and procedures. Additionally, we present a case study comparing shales from La Luna and Eagle Ford formations to demonstrate the workflow and its applicability.