Title : Evaluation of nanoparticle performance for enhanced oil recovery in harsh carbonate reservoirs: A mechanistic study with field-specific insights from Shadgan
Abstract:
While nanoparticle-enhanced oil recovery (nano-EOR) has shown promise in controlled laboratory settings, its application in extreme reservoir environments-characterized by high salinity, elevated temperature, and heterogeneous carbonate lithology-remains underexplored. This study presents a comprehensive mechanistic evaluation of five engineered nanoparticles (SiO₂, Al₂O₃, TiO₂, Fe₃O₄, and nano-clay) under conditions mimicking the harsh Shadgan field (75°C, 180,000 ppm salinity, 45 cP oil viscosity). We integrate advanced characterization techniques-including in situ zeta potential, temperature-dependent interfacial tension (IFT), and post-flooding SEM/EDS-with core-flooding experiments and a 1D advection–dispersion transport model to deconvolute governing mechanisms. Results reveal that SiO₂ outperforms other nanoparticles due to its sustained colloidal stability (zeta ≈ −42 mV), profound wettability shift (120° to 45°), and low retention (8.5% ± 1.2%), yielding the highest incremental recovery (9.2% ± 0.9% OOIP). In contrast, Fe₃O₄ exhibited severe aggregation and the highest retention (24.8% ± 3.5%), leading to negligible recovery improvement. A strong inverse correlation (r = −0.89) between retention and recovery underscores retention as a critical performance-limiting factor. We further propose a hybrid SiO₂–TiO₂ formulation to synergize IFT reduction and wettability alteration while mitigating retention. This work provides novel mechanistic insights into nanofluid behavior in harsh carbonate systems and delivers a robust, transport-informed selection criterion for field-scale pilot design.
Keywords: nanoparticles; enhanced oil recovery; high salinity; wettability alteration; retention; transport modeling; carbonate reservoirs; hybrid nanofluids
