Santos, Verena Filgueiras Borges dos; Santos, Adriana Vieira dos; Rodrigues, Pâmela Dias; Santos, Flávia Cristina Cerqueira dos; Simonelli, George; Santos, Luiz Carlos Lobato dos
Resumo:
The decline in oil production from mature fields and the increasing global energy demand reinforce the need for advanced technologies for Enhanced Oil Recovery (EOR). Microemulsions containing plant-based surfactants show promising potential for mobilizing residual oil in reservoirs due to their ability to reduce interfacial tension and alter interfacial properties, thereby enhancing recovery efficiency.
Objective
This study aimed to formulate and characterize microemulsion systems based on plant-derived surfactants for EOR applications, evaluating their physicochemical properties and potential for reducing interfacial tension under simulated reservoir conditions.
Methods
Three microemulsion formulations were prepared ex situ, using a surfactant derived from coconut oil, a co-surfactant (isopropyl alcohol), pine oil as the oil phase, and distilled water as the aqueous phase. The formulations MEOPI1 (more aqueous), MEOPI2 (intermediate), and MEOPI3 (more oily) were characterized in terms of viscosity, density, refractive index, electrical conductivity, pH, and interfacial tension at 60 °C, a representative temperature of oil reservoirs.
Results
The formulations demonstrated broad stability, isotropic characteristics, and translucency. Key findings include:
Interfacial tension: Significant reduction compared to pure water (66.18 mN/m at 60 °C). MEOPI1 had the lowest value (22.9 mN/m), while MEOPI3 reached 23.8 mN/m, demonstrating efficiency in oil mobilization.
Dynamic viscosity: MEOPI3, with a higher proportion of the oil phase, exhibited the highest viscosity (1.647 cP), suitable for improving sweep efficiency in reservoirs.
Electrical conductivity: Decreased from 2,371 µS/cm (MEOPI1) to 144 µS/cm (MEOPI3), reflecting the composition's influence on the microemulsion structure.
Refractive index: Ranged from 1.366 (MEOPI1) to 1.425 (MEOPI3), indicating greater interaction with oil in the more oily formulations.
Conclusion
The results confirm the potential of microemulsions formulated with plant-based surfactants for EOR applications. MEOPI3 emerged as the most efficient formulation due to its higher affinity for hydrophobic contaminants, higher dynamic viscosity, and lower interfacial tension. This approach offers significant environmental advantages compared to commercial surfactants and represents an effective and sustainable solution for enhancing oil recovery in challenging reservoirs.
