A new model is developed to predict flow behaviors including flow pattern, pressure gradient and holdup for oil-water flow in horizontal and slightly inclined pipes. The model is based on the universal principle that a system stabilizes to its minimum total energy. The structural configurations observed in two-phase flow systems can be interpreted in terms of total energy minimization. Performance of the developed model is tested against several experimental data, and comparisons with existing models are presented. It is evident from the results and comparisons that the model estimates the pressure gradient and flow pattern very well. The model provides extensive information about oil-water flow characteristics. (C) 2010 Elsevier Ltd. All rights reserved.