Nanomodel visualization of fluid injections in tight formations

摘要: The transport and phase change of a complex fluid mixture under nanoconfinement is fundamental importance in nanoscience, limits the recovery efficiency from tight oil reservoirs (<10%). Herein, through experiments supporting theory we characterize nanoconfined mixture. Our nanofluidic platform, nanomodel, replicates shale terms mean pore size (∼100 nm), permeability (∼μD) porosity (∼10%). We screen conditions for most promising EOR strategies, directly quantifying their pore-scale underlying mechanisms. find that immiscible gas (N2) flooding presents prohibitively large capillary pressure threshold (∼2 MPa). Miscible (CO2) eliminates this leading to film-wise stable displacement with high efficiency. Strong forces present barriers as well opportunities strategies unique nanoporous by transitioning miscible an condition locally within reservoir. These results quantify mechanisms applicable fluids, direct implications unconventional media more broadly.