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Enhanced oil recovery (EOR) is a proven method to increase oil production from the brown fields. One of the efficient EOR methods is injecting surfactants to release the trapped oil. However, few unconsolidated behaviours were observed in both field and laboratory practice. In this study, a new framework was adapted to evaluate the continuous surfactant flooding (CSF) in Bentiu reservoir. The study aims to quantify the expected range of the oil production, recovery factor and residual oil saturation (Sor). The motivation came from the oil demand in Sudan and the insufficient cores. The framework adopted in the study includes numerical simulation modelling and proxy modelling. Thirty-six cores obtained from the field were revised and grouped into five main groups. The interfacial tension (IFT) data were obtained experimentally. The CSF sensitivity study was developed by combining different experimental design sets to generate the proxy model. The CSF numerical simulation results showed around 30% additional oil recovery compared to waterflooding and approximately oil production between (20–30) cm3. The generated proxy model extrapolated the results with concerning lower ranges of the input and showed an average P50 of oil production and recovery of 74% and 17 cm3, respectively. Overall, the performance of CSF remained beneficial in vast range of input. Moreover, the generated proxy model gave an insight on the complexity of the interrelationship between the input factors and the observants with a qualitative prospective factors. Yet, the results confirmed the applicability of CSF in core scale with an insight for field scale application. [ABSTRACT FROM AUTHOR]

Surfactant flooding is a proven Enhanced Oil Recovery (EOR) technique used for mobilizing residual oil trapped in the reservoir. The mechanism of surfactant injection into reservoirs for improving oil recovery factor is to alter the fluid/fluid interaction by reducing interfacial tension between oil and brine. Besides, they alter fluid/rock properties via wettability alteration of the porous medium. Surfactant flooding has been applied on several field pilot projects. This research mainly focuses on investigating the continuous surfactant flooding for Bentiu oil reservoir in Sudan. The main method used in this study is numerical analysis of compositional flow using STARS software provided by the Computer Modelling Group Company (CMG-STARS). The research also proposed new surfactant for the continuous flooding. Moreover, the surfactant ability to increase the recovery factor was studied and compared to the traditional water flooding recovery method. Furthermore, for accuracy purposes, the risk of surfactant adsorption in the typical heterogeneous field was studied. The surfactant adsorption was calculated from static batch adsorption test by the surface tension method. The simulation results showed that the newly proposed surfactant improved total oil recovery by ∼70%. The surfactant flooding showed lower water cut when compared to conventional water flooding. The improvement in the oil recovery and water cut was a good indication for the suitability of surfactant flood in the heterogeneous reservoir. [ABSTRACT FROM AUTHOR]