Alkaline-Surfactant Flooding in Niger-Delta: An Experimental Approach

Oil and gas production in Nigeria, recently advanced into secondary method of recovery of hydrocarbon aiming at tertiary recovery methods known as Enhanced Oil Recovery. It is of great importance to start the preparation for this phase now. Alkaline-Surfactant flooding is a tertiary recovery method used to produce extra oil from mature fields where oil is trapped due to capillary forces. These alkali are added to mostly reactive crude; they react with the naphthenic acid in the crude oil which forms a crude soap through the process of saponification, but most times, this crude soap are not sufficient, so surfactant are further injected to optimize its concentration in order to effectively reduce the interfacial tension between oil and formation water. Three conventional alkalis (NaOH, Na₂CO₃ and KOH) and two synthetic surfactant (Xero Detergent and Sodium Dodecyl Sulphate) were used as Enhanced Oil Recovery agent for a sand pack flood test in the laboratory. The comparative result showed that the Na₂CO₃ at 1%w/v concentration was better, though the KOH at 2%w/v concentration gave the best result marginally. It was also observed that the XD at 0.1%w/v concentration gave a result that can be compared to that of 1%v/v concentration SDS. Which shows that XD can be used as a substitute for SDS with low cost and availability been added advantage. Additional oil recovery after waterflooding for NaOH, Na₂CO₃, KOH, XD and SDS are 13.3%, 18.2%, 17.5%, 11.5% and 15.2% respectively.