Synergistic effect of dual hydrogen-donor deep eutectic solvent for performance improvement of fracturing-oil expulsion fluids

Abstract

Petroleum remains the main source of energy consumption over the past decade. The development of rich unconventional oil reservoirs is a huge challenge. Clean fracturing fluids (CFFs) have gained considerable attention for the unconventional reservoir development, owing to their integrated capabilities of fracturing and oil expulsion. Performance of CFFs is a vital factor in enhancing oil recovery. In this work, a ternary deep eutectic solvent (DES) with dual hydrogen donors (HBDs) was developed as a novel and green medium for improving CFF performance. With the hydrogen-bonding interactions, the ternary DES enable a robust micelle network, thereby strengthening the rheological property, temperature resistance and drag reduction performance of CFFs. The salt resistance performance was improved due to the ion–dipole interaction between HBDs and salt cations, decreasing the interactions between salt cations and surfactants. The DES also increase the imbibition efficiency from 30.7 % in 98 h to 43.7 % in 62 h. Besides, the gel breaking performance and reusability of gel-breaking fluid were enhanced in the presence of DES. The ternary DES showed more effective reinforcement for CFF properties as compared with binary DES, due to the synergistic effect of dual HBDs. This work will provide a promising alternative for intensifying CFF performance.