Amphoteric and cationic surfactants for enhancing oil recovery from carbonate oil reservoirs

In recent decades, chemical surfactants have significantly been utilized in enhanced oil recovery (EOR) process and researchers still have a distinctive look to applications of these chemicals. In this study, Hexadecyl-tetra Methyl Ammonium Bromide (henceforth; HTMAB) and Hexadecyl-Amino-Benzene Sulfonic Acid (henceforth; HABSA) were used as surfactants to derive relative permeability curves for carbonate rocks. To this end, the contact angles for different concentrations of the two surfactants in solutions were measured in the bulk volume of kerosene using a VIT-6000 apparatus. Additionally, the unsteady state core flooding process (JBN method) in three steps (water injection, surfactant HTMAB injection and surfactant HABSA injection) was performed to analyze the relative permeability measurements and finally oil recovery was evaluated at different conditions. According to the results of this study, HTMAB has the maximum oil recovery factor of 63.50% in comparison with the other scenarios assessed in this work. Hence, it is concluded that in carbonate rocks, HTMAB is more effective than HABSA as it has better efficiency to modify the wettability toward water-wet. Furthermore, for HTMAB flooding, it is indicated that relative permeability curves intersection depicts the water saturation of 0.67 and according to the outcomes; the end-point of water is less than oil in relative permeability curve. Therefore, it can be concluded that HTMAB is more impressive than HABSA in wettability variation of these sorts of rocks.