Experimental investigation of impact of low salinity surfactant flooding for enhance oil recovery: Niger Delta field application

Oil reserves in the Niger Delta have been gradually decreasing due to the increased production. New large field discoveries are scarce, thus there is need to improve on the production from existing reserves. Low salinity surfactant flooding (LSSF) is a potential enhanced oil recovery process to increase oil production in the Niger Delta oil fields. In this study, sodium dodecyl sulphate and ethanol were used as surfactant to study the significance of the surfactants on oil recovery. Sand packs were used as formation sample in the laboratory. This was soaked with oil of 24.36° API and specific gravity of 0.9436. Low salinity water was used as a displacing fluid in the secondary recovery mechanism. However, sodium dodecyl sulphate and ethanol (78% vol.) was introduced into the sand packs. The sodium dodecyl sulphate reduced the interfacial tension as obtained using tensiometer machine. Ethanol was used in the second case as surfactant. The result of the work shows that sodium dodecyl sulphate had oil recovery of 16.1, 16.9, 19.0 and 19.3% respectively at different surfactant concentrations 0.2, 0.3, 0.35and 0.38% wt. respectively; while ethanol (78% vol.) had oil recovery of 1.5%. The study noted that sodium dodecyl sulphate is a good surfactant for enhanced oil recovery for crude oil with the specified API gravity. In addition, interfacial tension reduction and change in rock wettability were the working mechanisms for the sodium dodecyl sulphate to increases oil recovery from reservoirs. The work showed that sodium dodecyl sulphate maintained low interfacial tension through the flood process.