Evaluation of a new green synthesized surfactant from linseeds - chemical EOR implications from sandstone petroleum reservoirs

Abstract

Surfactants are materials with different applications in industries. The development of surfactants and the reduction in their associated harmful effects are among the most crucial matters that must be taken into account to increase their efficiency. Surfactants are widely employed in chemical enhanced oil recovery, yet sometimes these materials are not environmentally friendly and economically affordable. Hence, the natural surfactants were introduced to address this issue. However, they show poor efficiency in the main mechanisms of oil recovery enhancement, including wettability alteration and interfacial tension reduction. Herein, a new anionic surfactant was synthesized from the natural base material (linseeds) revealing high efficiency in chemical enhanced oil recovery. In addition, esterification and sulfonation methods were applied to conduct the synthesis process. Following the conduction of the synthesis process, the synthesized surfactant was characterized by the use of Fourier transform infrared spectroscopy (FTIR), hydrogen nuclear magnetic resonance (HNMR), and thermogravimetric analysis (TGA) to ensure the accuracy of the synthesis process and the appropriate thermal stability. The solution properties of the surfactant synthesized from linseeds, abbreviated as PELS, were analyzed through pH and the electrical conductivity at different concentrations. It must be regarded that micellar behavior is an essential parameter for each surfactant normally analyzed with surface tension (ST) and interfacial tension (IFT) respectively expressing 96% (28.97 to 0.99) and 59% (74.5 to 28) optimization. The fact that all of these experiments indicate the value of 1500 ppm as the critical micelles concentration must be taken into consideration. The wettability alteration was analyzed through a contact angle experiment on the sandstone surface showing a 58% optimization once the contact angle reduced to 54.5° in the water-wet zone. Owing to the presence of salt in the reservoir condition, NaCl was utilized as a sample to analyze the ion effect on the PELS performance. Meanwhile, it demonstrated good compatibility, especially in IFT reduction, reducing the IFT value from 0.99 in CMC point to 0.26 mn/m in the presence of NaCl ions. Several other surfactant properties, such as foamability, emulsion stability, and salt compatibility were analyzed for chemical enhanced oil recovery purposes. The adsorption of surfactant molecules on the rock surface reduces the surfactant efficiency and is of significant importance. This issue was evaluated and the pertinent results were compared with common models of isotherm absorption. Ultimately, the results of core flooding experiments using sandstone sample illustrated a 7.9% increase in the recovery factor and the required relative permeability charts were plotted via JBN method.