Extraction, characterization and evaluation of saponin-based natural surfactant for enhanced oil recovery

Abstract

To minimize environmental impact and costs, natural surfactants are suggested as an ecologically sustainable replacement for synthetic surfactants. The aim of this work is to evaluate the efficiency of low-cost saponin-based natural surfactant (SBNS) from Vernonia amygdalina ( VA ) leaves for enhanced oil recovery (EOR). Furthermore, the study investigated the IFT behaviour of SBNS at oil-water interface and the emulsion behaviour and oil displacement efficiency of SBNS. The SBNS was obtained via ultrasonic extraction of dried VA leaves in a water bath, centrifuging the obtained liquid mixture and freeze drying to evaporate to dryness. Thereafter, Fourier-transform infrared spectroscopy (FTIR) and high-performance liquid chromatography were used to characterize the extracted SBNS. Moreover, tensiometer (Easy-Dyne KRUSS) was used to study the interfacial tension (IFT) behaviour of the SBNS at oil-water interface. Also, the SBNS ability to form stable emulsion in the presence of crude oil was determined. Finally, oil displacement by SBNS solution was investigated under simulated reservoir conditions (3000 psi and 100 °C) with high-pressure high-temperature (Fars EOR) core flooding equipment. The performance of SBNS was compared to commercial non-ionic surfactant 4-octylphenol polyethoxylated (TX-100). Experimental result indicated that the SBNS reduced the IFT at oil-water interface. The natural surfactant lowered the IFT of the oil-water interface from 18.0 to 0.97 mN/m. Moreover, emulsions formed with SBNS showed good stability characterized by a decrease in the median drop diameter with an increase in SBNS concentration. Finally, oil displacement test shows that oil recovery of TX-100 and SBNS increased by 9% and 15% original-oil-in-place (OOIP), respectively. Hence, SBNS is recommended as an appropriate substitute for conventional surfactant due to its inexpensive raw material, lower toxicity, and higher efficiency.

An Overview of Natural Surfactant Application for Enhanced Oil Recovery

“…Future studies on natural surfactant should focus on modeling their flow and transport behavior in porous media and scaling up natural surfactant application for field studies. Cumulative oil recovery of surfactant flooding [36].…”

“…The surfactant lowered the IFT from 28 mN/m to 3 mN/m and generated stable foams. Imuetinyan et al [36] evaluated the performance of natural surfactant extracted from Vernonia Amygdalina at oil-water interface. The natural surfactant lowered the IFT at oil-brine interface from 18 mN/m to 0.97 mN/m in the presence of NaCl brine.…”

“…0.4 wt.% of the surfactant generated from palm kernel oil yielded 24.3% incremental oil recovery, respectively. Imuetinyan et [36] recorded 15% incremental oil recovery from core flooding procedure of saponinbased natural surfactant performed at high-pressure high-temperature condition. The SBNS performed better than conventional Triton X-100 under the same condition as depicted in Figure 3.…”

Review on Potential Application of Saponin-Based Natural Surfactants for Green Chemical Enhanced Oil Recovery: Perspectives and Progresses

“…Saponins are biodegradable, non-toxic, triterpene, or steroidal glycosides (lipophiles) distributed abundantly in plants with essential structural diversity due to the presence of other functional groups such as hydroxy, carboxyl, acetate group, and esteric bond. ,,− Saponins have excellent thermal stability, salt tolerance, and hardness tolerance. They also possess excellent emulsification, solubilization, and foaming properties, which makes them suitable for many industrial applications ,− (Figure ). Saponins have diverse applicationsthey are applied as additives in beverages, cosmetics, confectioneries, and pharmaceutical products. ,,− Since the pioneering work of Rignano and Lionetti in 2009 to extract saponin from the Chilean soap bark tree ( Quillaja saponaria Molina ), there have been considerable studies in the extraction of saponins for EOR applications from various sources .…”

Evaluating the Potential of Zwitterionic Surfactants for Enhanced Oil Recovery: Effect of Headgroups and Unsaturation

“…Surfactant flooding, a chemical EOR method, is one of the most widely used methods for recovering additional oil from reservoirs. − Surfactants are amphiphilic and surface-active compounds with a hydrophilic head and hydrophobic tail. − They are used for reducing interfacial tension (IFT) of the fluid–liquid interface and altering the wettability of the rock–fluid interface to a wetting condition suitable for oil recovery. − Altering the wettability of the porous media to the aqueous-wetting condition causes an increase in the relative permeability of oil. − Meanwhile, by reducing the IFT, the capillary number N c is increased as depicted in eq , which consequently lowers the residual oil saturation and enhances the displacement efficiency. − N normalc = μ × v σcosθ where N c is the capillary number, μ represents the viscosity, v represents the velocity, σ represents the interfacial tension, and θ is the contact angle.…”