Experimental assessment of a lysine derivative surfactant for enhanced oil recovery in carbonate rocks: Mechanistic and core displacement analysis

Enhanced oil recovery (EOR) from carbonate reservoirs is of great challenge due to the complex geology that originated from high rock heterogeneity and viscous fingering phenomenon during a displacement process. One of the highly applicable EOR approaches is the utilization of surfactant especially for the aims of foam generation, wettability alteration, emulsion stability and well stimulation in petroleum industry. The dominant mechanisms of surfactant for increasing oil production are wettability alteration of reservoir rock and interfacial tension (IFT) reduction of oil-water system resulting in higher sweep efficiency by diminishing the adverse capillary forces existing in the porous media and easier flow of the residual oil toward the producing wells. In the present study, (S) 2-amino-6-dodecanamidohexanoic acid as an amino acid-based surfactant, is proposed in order to evaluate an EOR application. Firstly, the pH, density and viscosity of the surfactant solutions were measured regarding the impact of salt concentration. Afterwards, IFT and wettability tests were conducted by means of pendent drop and sessile drop methods, respectively. The impact of salt concentration was also examined on the IFT behavior. Moreover, the recovery potential of the proposed amino acid-based surfactant via core displacement test was compared with a traditional brine injection process. Consequently, it is found out that increasing salt concentration has an increasing effect on both 1FT trend and the values of critical micelle concentration. Additionally, change in carbonate rock wettability from oil-wet to neutral-wet was also observed. Finally, it is proved that surfactant flooding can improve the oil recovery factor more than the time at which water injection is used. (C) 2017 Elsevier B.V. All rights reserved.