LAUSR

The use of CO2 as a fracturing fluid for reservoir stimulation to enhance oil and gas recovery in low-permeability formations is widespread. However, during the CO2 injection process, the low viscosity of supercritical CO2 (SC-CO2) at high temperature and pressure conditions usually causes serious fluid loss in porous media, thus restricting its efficient utilization. In this work, the dynamic filtration control properties of nanoparticle-enhanced dry SC-CO2 foams in porous media were explored, and the effects of nanoparticle and surfactant concentration, foam quality, pressure drop, temperature, and permeability were systematically studied. The results showed that the SC-CO2/liquid interfacial viscoelasticity modulus and the corresponding foam viscosity were improved by the adsorption of silica nanoparticles at the SC-CO2/liquid interface. At high foam quality (⩾90%), the nanoparticles reduced the amount of coarse bubbles and prevented bubble disproportionation, both of which helped to maintain a higher ...