Surfactants for Enhanced Oil Recovery: Progress and Innovations over the Past Decade

Abstract

Surfactant-based strategies have emerged as key approaches for enhancing oil recovery (EOR), particularly in mature reservoirs where conventional production methods leave a substantial fraction of oil unrecovered. This review provides a comprehensive and critical assessment of advances reported from 2014 through August 1, 2026, focusing on the physicochemical mechanisms governing oil mobilization, interfacial control, and emulsion behavior under reservoir-relevant conditions. A structured literature survey retrieved 613 records from the Scopus and Web of Science databases, yielding 493 unique records after database merging and duplicate removal; 64 studies were selected after thematic screening for detailed discussion. Complementary sources identified through targeted manual searching and citation tracking were also incorporated into the review. This analysis reveals that recent progress has been driven not only by interfacial tension (IFT) reduction and wettability alteration but also by improved control of adsorption, transport phenomena, and fluid behavior in porous media. Beyond conventional surfactant systems, this review highlights the increasing role of hybrid and advanced formulations, including polymer–surfactant systems, nanoparticle-assisted approaches, biobased surfactants, and microemulsion-driven processes, which have expanded the applicability of EOR under harsh conditions such as high salinity and elevated temperatures. Particular emphasis is given to the interplay between formulation design and reservoir characteristics, demonstrating that performance is strongly governed by fluid–rock interactions, retention phenomena, and system stability. In addition to consolidating recent advances, this work critically discusses persistent limitations, including surfactant loss, chemical instability, economic constraints, and the challenges associated with scaling laboratory results to field applications. The analysis further underscores the growing importance of predictive modeling, formulation optimization, and sustainability-driven strategies in guiding future developments. Overall, the current literature indicates that progress in surfactant-based EOR will depend on the integration of tailored formulations, hybrid systems, and mechanistic understanding capable of addressing the complexity of real reservoir environments.