1. A method of modeling one or more reservoirs using one or more well logs, each for a well at a location and each including one or more Relative amount of Small Size Range of the Size Spectrum of Clastic Particles (RSSRSS) values versus depth, the method including: for one or more well logs: identifying one or more facies units based on RSSRSS values; determining a thickness of one or more facies units; and determining a facies type of one or more facies units; categorizing one or more facies units; and connecting one or more facies units to create a reservoir model.