Curbelo, Fabiola Dias da SilvaGarnica, Alfredo Ismael CurbeloDantas, T. N. CastroBarros Neto, Eduardo Lins de2021-11-222021-11-222017-07-18CURBELO, F. D. S. ; GARNICA, A. I. C. ; DANTAS, T. N. C. ; BARROS NETO, E. L.. SYNERGISM STUDY OF MIXTURES OF IONIC AND NONIONIC SURFACTANTS IN ENHANCED OIL RECOVERY ADSORPTION. BRAZILIAN JOURNAL OF PETROLEUM AND GAS, v. 11, p. 91-97, 2017. Disponível em: http://www.portalabpg.org.br/bjpg/index.php/bjpg/article/view/567. Acesso em: 24 jun. 2021. http://dx.doi.org/10.5419/bjpg2017-0008.1982-0593https://repositorio.ufrn.br/handle/123456789/44970Adsorption of surfactants from aqueous solutions in porous media is fundamental in enhanced oil recovery (EOR) because surfactant loss reduces the effectiveness of the chemical solution injected, making the process economically unfeasible. This paper analyzes surfactants’ synergistic effects in adsorption and enhanced oil recovery. This study used nonionic (nonylphenol 20 ethylene oxide – R200) and anionic surfactants (saponified coconut oil – OCS and base soap - SB) with the two mixtures studied (R200/OCS and R200/SB). The mixture R200/SB, due to its higher viscosity because of the presence of SB, saturated the ionic surfactant (SB) faster, reaching a higher oil recovery (70.0%). The addition of SB surfactant in the R200 solution led to an increase in oil recovery (70.0%) when compared to R200 alone (64.5%)SurfactantSynergismAdsorptionCritical micelle concentrationEnhanced oil recoveryarticle10.5419/bjpg2017-0008