We analyze correlations between velocity, permeability, and porosity in three tight sand reservoirs. Flow zone indicator and effective specific surface area methods are introduced to analyze the relations between these properties. Correlations between velocity, permeability, and porosity of clean tight sands are shown to be well characterized after binning the data into zones with distinct effective specific surface or flow zones. Introduction Reservoir characterization, an important tool for analyzing production potential of a prospective zone, is challenging in unconventional reservoirs, due to limited understanding of the petrophysical characteristics and the governing factors of flow through these formations. In this paper, we analyze the petrophysical properties and correlations between velocity, permeability, and porosity behavior in tight gas sands.