Evaluation of modified cashew nutshell liquid as natural surfactants for chemical flooding in sandstone oil reservoirs

Abstract

Bio-based oilfield chemicals are gaining attention due to their availability, cost-effectiveness, and non-toxic nature. Surfactants facilitate recovery of residual oil by reducing the interfacial tension between two immiscible fluids. Cashew nutshell liquid (CNSL) extracted from Anacardium occidentale waste shells was modified using triethanolamine and evaluated as a natural alternative to traditional surfactants. Phase behavior analysis, interfacial tension, critical micelle concentration (CMC) measurements, and core flooding analysis were performed to ascertain the compatibility and recoverability of the cashew nutshell liquid derivatives on sandstone reservoirs. Interfacial tension was reduced from 10.46 to 1.66 mN/m at CMC of 1 g/L. Additional recovery factor and displacement efficiency of 12% OOIP and 32.5%, respectively, was achieved at laboratory temperature. The effect of temperature on residual oil recovery was determined by subjecting the oil displacement experiment to reservoir temperature of 80˚C, resulting in recovery factor and displacement efficiency of 9% OOIP and 25%, respectively.