Study of Gellan for Polymer Flooding

This article reports the efficiency of polymer-gellan as an oil displacement agent in comparison with water and polyacrylamide (PAM), which is traditionally used in the oil industry. The terrigenous and carbonate rocks used as core materials were characterized by scanning electron microscope. The porosity and permeability of the core materials were also determined. Sol-gel transition of polysaccharide-gellan in the presence of various salts was studied. It was found that the effectiveness of salts to enhance gelation follows this order: CaCl2 approximate to MgCl2>KCl>NaCl. Influence of storage time and temperature on the viscosity of gellan was evaluated. Laboratory experiments on water flooding and polymer flooding methods were carried out on sand-packed model. Results of oil displacement experiments from sand-packed model and core samples were compared. It was shown that gellan and PAM show almost equal values of the oil displacement coefficient, which is 60-65%, while injection of water gives only 30-45%. Oil displacement process was visualized on cross sections of sand-packed model. Optimal concentration of gellan solution for oil displacement, which depends on absolute permeability of rock, was found.