Improving Recovery Through Surfactant Desorption on An Oil Wet LimestoneReservoir

The current paper investigates on reducing surfactant adsorption after its application onto limestone surface by Ethelene Oxide (EO) conjugated with Sodium Dodecyl Sulphonate (SDS) to improve oil recovery. SDS has been treated with EO as a nonionic surfactant with low critical micelle concentration to increase its hydrophilic nature that leads to desorb itself from oil wet surfaces like limestone reservoirs after altering wettability. Although, surfactant has a great impact on Oil recovery, adsorption makes them ineffective. It’s been a great concern for petroleum industry during enhanced oil recovery operations. This study focuses on finding a mechanism to reduce SDS adsorption on an oil wet limestone core sample and altering its wettability through EO at different concentrations. Critical Micelle Concentration (CMC) of SDS was found at 500 ppm by conductivity test was chosen to reduce interfacial tension between oil and brine composition. Due to surface charge variation SDS was observed to adsorb onto limestone surface through core analysis. It has been flooded after water under core flooding operations, which shows near to field observations. For reducing this effect, EO was introduced with different concentrations to alter the hydrophilic properties of SDS. Being limestone oil wet surface, which leads SDS to adsorb onto its surface. Since, SDS would adhere onto the inner layers of core lead to alter wettability by recovering crude. The recovery of crude from a limestone core has been carried in two ways. Firstly, SDS was treated to get adsorb onto the core surface and secondly desorption of SDS by enhancing its hydrophilic nature through EO. By its application, the recovery of oil has been improved by reduction in adsorption of SDS successfully have been reported.