On of the most important problems of water-flow control and water flooding is heterogeneity of porous media. This problem causes water to canalize through high permeable zones and low permeable zones remain intact A possible method for decreasing this unwanted phenomenon is bioplugging of high permeable zones. In this study the efficiency of microbial treatment for improvement of water flooding of Persian gulf in a heterogeneous micromodel with 2 layers of low and high permeable zones was visualized using 2 sets of experiments. The first one was water flooding and the other was microbial treatment with a mixed culture of microorganisms that followed by water flooding. Results of visualization and image analysis studies showed that water canalizing through high permeable layer in the first experiment decreased considerably via bioplugging of this layer and the oil recovery enhanced considerably.