Investigation on surfactant desorption isotherm to enhance oil spontaneous recovery in a low permeability core

Surfactant enhanced oil recovery depends on the interfacial tension (IFT) reduction and wettability alteration in the rock/oil/brine system. An adequate amount of surfactant within the system is vital during the application. The aforementioned problem becomes more sensitive in a low permeability formation when the adsorption is much higher than the desorption. This study, therefore, investigated the surfactant desorption isotherm using sodium dodecylbenzene sulfonate (SDBS) as a surfactant and tight Berea sandstone as adsorbent. The desorption of SDBS was found to follow a Langmuir type isotherm. Owing to the Langmuir characteristics, the desorption increased up to four folds by reducing the salinity of the process water from 3 wt.% to 1 wt.%. The study was extended in a spontaneous imbibition tests for oil recovery. The desorbed SDBS enables an increase in total oil recovery by 2%. The results were subsequent to a more favourable IFT and a mitigation in the narrow-pore blockage.