Effect of unconventional surfactant on wettability alteration for enhanced heavy- oil recovery in sandstone reservoirs

With depletion of global light oil reserves and the challenges associated of developing new wells have led to a shift in focus towards heavy crude oil as a vital component of future global energy mix. Heavy crude oil reserves are abundant and their development is crucial to meeting the increasing energy demands. The wetting condition of a crude oil/brine/rock system plays a significant role in determining transport properties and oil recovery. Research has shown that some local materials possess similar characteristics as the conventional materials. This study investigates the potentials of locally formulated non-edible surfactant in altering rock wettability and improving recovery during chemical flooding of core plugs obtained from Niger delta formation. The surfactant was screened for critical micelles concentration and aqueous compatibility and its performance in wettability alteration and oil recovery was evaluated using a conventional surfactant as a reference. Results indicates that the locally formulated agents effectively reduced the interfacial tension (IFT), altered the wettability condition from slightly oil-wet to more water-wet, resulting to increased oil recovery. The performance of locally formulated EOR (Enhanced Oil Recovery) agent (SLE) was compared with conventional surfactant (SDS) experimentally by chemical flooding, yielding a recovery of 22.5% of original oil in place (OOIP) for SLE and 24.7% of original oil in place (OOIP) for the conventional Sodium Dodecyl Sulfate, indicating a percentage difference of 8.9%. The findings suggest that SLE is a promising candidate for enhanced heavy crude oil recovery applications in sandstone reservoirs, offering a viable alternative to conventional surfactants.