Visualization of water and surfactant floods in oil-saturated porous media

The flow of water and 1% surfactant solution displacing oil through homogeneous and non-homogeneous porous media have been studied experimentally. The results are shown by taking the photographs of unstable interface at regular interval of time. These photographs suggest that the spreading of the moving interface in lateral direction is more for 1% surfactant solution displacing oil than for water displacing oil and also the interface is more stable for surfactant flooding in the bed. The wavelengths of viscous fingers measured from the experiments are found to be in good agreement with the theoretical predictions for homogeneous bed. The percentage oil recovery at breakthrough is improved considerably with the use of surfactant solution. Effect of flow rate on recovery and breakthrough time has also been studied. Finally, the effect of non-homogeneous packing on the growth of fingers has been studied by creating non-homogeneous medium in an otherwise homogeneous porous medium.