Title : Development of surface-functionalized tailored polymer blend for enhanced oil recovery for non-producing reservoirs
Abstract:
Maximizing hydrocarbon recovery from mature reservoirs demands advanced Enhanced Oil Recovery (EOR) technologies to meet global energy requirements. This study reports the chemo-selective synthesis of a novel polymer blend (PB) composed of acetylated guar gum (aGG) and native guar gum (GG). FTIR analysis confirmed the formation of ester groups (1733 cm⁻¹) and the polymer combination (3467-3600 cm⁻¹). Among four blend ratios, the aGG 4:1 GG composition was identified as the most stable with the lowest crystallinity, based on electrode potential and Gibbs free energy calculations. Rheological analyses revealed desirable pseudoplastic and viscoelastic behaviour critical for enhancing sweep efficiency. The optimal PB exhibited sweep efficiency of 3.37 mm² s⁻¹, low interfacial tension (IFT) of 27.0 dyne cm⁻², and an injection pressure of 2700 Pa. Contact angle measurements confirmed the most effective wettability alteration, reducing the angle to 61.1°, followed by aGG (74.2°) and GG (82.3°), indicating water-wet characteristics. Floatation and two-phase separation tests verified wettability reversal, with PB-treated carbonate rocks rapidly settling in the aqueous phase. Emulsification studies demonstrated that PB produced small, densely packed oil–water droplets, whereas aGG yielded moderately larger droplets and GG formed fewer, larger ones, reflecting lower efficiency. Oil Reservoir Simulating Bioreactor (ORSB) trials validated PB performance, achieving the highest incremental oil recovery of 8.31 % OOIP (total recovery enhanced from 47.6 % to 55.9 %), surpassing aGG (3.59 %) and GG (2.98 %). These results establish PB as a novel, cost-effective, and eco-friendly biopolymer capable of outperforming existing synthetic polymers in EOR.
