Investigation into the Oil Recovery Process Using an Organic Alkali-Amino Acid-Based Surfactant System

The development of combinatory flooding has evolved over the years to utilize the synergies that come into play upon combining more than one chemical agent in a chemical flooding process. This study focuses on investigating the synergies that exist in combining monoethanolamine (ETA) and sodium cocoyl alaninate (SCA) as an alkali-surfactant (AS) formulation for the enhanced oil recovery process. A conventional formulation made of sodium carbonate (Na2CO3) and sodium dodecyl sulfate (SDS) was used for a comparative purpose. The proposed formulation proved to be compatible with the prepared hard brine. The ETA-SCA combination proved superior to Na2CO3-SDS in interfacial tension (IFT) reduction and wettability alteration. Addition of ETA to SCA synergistically reduced IFT to a low value of 4.73 × 10-2 mN/m at a surfactant concentration lower than the critical micelle concentration (CMC). ETA also played a synergistic role in improving the wetting power of SCA on quartz surface. The formulation also showed a high emulsifying ability owing to its superior IFT reduction capability. Static adsorption studies showed SCA to exhibit Langmuir-type adsorption behavior similar to SDS. The adsorption of SCA onto a sand surface was favorable, but ETA proved to reduce adsorption of SCA effectively at 0.3 wt %. The ETA-SCA and Na2CO3-SDS systems achieved additional oil recoveries of 31 and 25% original oil in place (OOIP) over conventional core flooding, respectively. The proposed AS formulation, therefore, showed better recovery potential in addition to its environmentally friendly nature.