Laboratory evaluation of red onion skin extract and its derivative as biomass-based enhanced oil recovery agents

Abstract

The use of natural alternatives as oilfield chemicals is gradually gaining attention among researchers due to their eco-friendly nature. The aim of this study was to determine the efficiency of red onion skin extract (ROSE) at recovering residual oil using the mechanism of surfactant flooding in sandstone reservoirs at reservoir conditions and compare its effectiveness in its pristine and modified state. ROSE was obtained by solvent extraction of the waste biomass (red onion skin) using acetone. The extract was chemically modified using glutaraldehyde. Phase behavior analysis in the presence of divalent ions at high temperatures (80 ˚C) and sandstone core flooding were performed to determine the fluid compatibility and displacement efficiency. Results show high compatibility and solubility of pristine (unmodified) and modified ROSE in soft and hard brine. Core flooding analysis showed a higher recovery of 32.1% and 36.5% original oil in place (OOIP) for 0.3 wt.% modified ROSE as compared to a recovery factor of 31.8% and 35.0 % OOIP for 0.5% unmodified ROSE in soft and hard brine respectively. It further reveals an increase in additional recovery at surfactant concentration in hard brine above critical micelle concentration (CMC). Results of statistical significance test showed that modified ROSE exhibited superior performance and a higher recovery relative to unmodified ROSE especially in hard brine. This is a novel work as red onion skin extract was derivatized with glutaraldehyde and successfully recovered additional residual oil under hard brine and reservoir temperature making them potential surface-active agents for chemical enhanced oil recovery.