The most commonly used secondary oil recovery technique is waterflooding. Macroscopic (or ammon) rock-pore characteristics such as pomity, permeability and irreducible water saturation and fluid properties such as viscosity have ken shown by pious investigators to influence the results of waterflooding and consequently ultimate oil recovery. The objectives of this study are to consider the influence of microscopic (or uncommon) rock-pore characteristics such as wetability, tortuosity, mercury intrusion volume, pore surface am, specific surface area, average pore diameter, median pomthmat diameter, pore length, apparent (skeletal) density and mercury recovery efficiency on residual oil saturation and oil recovery mlilzed in linear-core waterfloods. The mults were statistically analyzed to determine the quantitative relations between the various properties, and empirical equations were developed for predicting waterflood performance. The characteristics were analyzed and modeled at both breakthrough and floodout.