Experimental Study of CO2-Brine Two-Phase Flow in Sandstone Rock

Abstract The experimental study of carbon dioxide injection is primarily associated with CO2 geological storage in deep aquifers. The application of this technology requires detailed laboratory investigation of CO2 interaction mechanisms with formation rocks and fluids under reservoir conditions. The effectiveness of field-scale operations depends heavily on accurate core analysis that simulates simultaneous reservoir fluid flow. This study addresses the physicochemical behavior of CO2 and brine flow in siderite-containing sandstone rocks using laboratory techniques. Relative permeability measurements for brine and CO2 were conducted using X-ray radiography and low-field nuclear magnetic resonance (NMR) relaxometry. X-ray radiography enabled quantification of end effects and accurate relative permeability measurement in drainage and imbibition modes, while NMR relaxometry provided detailed fluid distribution across pores of varying sizes. Furthermore, this work investigates CO2 diffusion in porous media, combining experimental measurements under ambient conditions with pore-network modeling under reservoir conditions. The integrated use of these methods offers a robust characterization approach for two-phase flow in porous media, enhancing the reliability of reservoir simulations for CO2 storage in saline aquifers.