The effects of a novel Bio-based surfactant derived from the Acacia concinna plant on chemical enhanced oil recovery in the presence of various salts and a synthesized HSPAM polymer

Abstract

In this investigation, a unique idea of using a green surfactant derived from Acacia concinna (AC) plant and a hydrophobically modified copolymer consistingof acrylamide and styrene (HSPAM) for chemical enhanced oil recovery (CEOR) was studied. Firstly, the characteristics of AC green surfactant were comprehensively examined using different standard analyses, such as thermogravimetric analysis (TGA), nuclear magnetic resonance (NMR) spectroscopy, and Fourier-transform infrared spectroscopy (FTIR) techniques. The thermal stability test of the AC green surfactant demonstrated an acceptable 1.93% weight loss at the 80 °C (reservoir temperature). Additionally, 1H NMR and FT-IR investigations proved the structure of the saponin compound as the surfactant agent. Then, the compatibility tests revealed no precipitation at various concentrations of different salts. The efficiency of the AC green surfactant and HSPAM was examined with three different salts, including K2SO4, MgSO4, and NaCl, as three common salts present in the formation brine (FB) with salinities up to 97,000 ppm. Different experiments, including contact angle and interfacial tension (IFT) measurements, zeta potential measurements, emulsion and core flooding experiments were conducted and the efficiency of these materials for CEOR purposes was examined. The IFT results revealed that 1000 ppm is the critical micelle concentration (CMC) of AC green surfactant in deionized water (DIW). Based on the measured IFT and contact angle values, the most effective salt was K2SO4, followed by NaCl, and MgSO4. The addition of 2000 ppm of HSPAM polymer as the optimum concentration of HSPAM was very efficient in improving the performance of AC green surfactant and producing a higher quality of Winsor type III emulsion. The maximum oil recovery factor of 71.17% was achieved when 1000 ppm of AC green surfactant was injected as the tertiary recovery, and the value was further increased to 77.92% when 2000 ppm of HSPAM and 1000 ppm of AC green surfactant were injected as the tertiary recovery.