Application of Surfactant-based enhanced oil recovery in carbonate Reservoirs: A critical review of the opportunities and challenges

The oil production from carbonate formations is low because of complicated compositions, formation hetero-geneity, oil-wet/mixed wet conditions, etc. Primary recovery depends on the reservoir's natural resources for production and is often supplemented by secondary recovery methods such as water flooding or immiscible gas injection to generate an artificial drive and complement reservoir energy. Tertiary recovery strategies should be used to mobilize residual oil saturation and increase oil recoveries from these reservoirs using various chemical flooding and chemical agent systems. Polymer flooding, surfactant flooding, alkali flooding, and combinations of these flooding methods are different types of Chemical flooding EOR (C-EOR) technology. Surfactant flooding procedures have been regarded as reliable EOR methods for field utilization because they minimize interfacial tensions and modify reservoir rock wetting characteristics, reduced capillary forces and thus promote oil re-covery. This paper provides a review of field projects and large-scale operations of surfactant flooding in car-bonate reservoirs. The fundamental processes of various chemical systems, as well as the interactions of various compounds with reservoir rocks and fluids, have been examined. After a sequence of assessment steps, the required surfactant flooding for a range of specific reservoir conditions is determined. The properties of a sur-factant such as formulation and characteristics of reservoirs such as temperature, salinity, pH, rock permeability, formation type, wettability and other considerations are discussed. Moreover, since carbonate reservoirs are distinguished with a considerable heterogeneity, high temperature, and high salinity conditions, surfactant and polymer choosing for these kind of reservoirs is a difficult process that requires experimental test to obtain the best quantity and composition of chemicals. Field project design and technical insights can be used to generate innovative strategies that will have a direct effect on the international oil supply in the immediate future.