In-situ investigation of the impact of spreading on matrix-fracture interactions during three-phase flow in fractured porous media

摘要: Abstract This paper presents the results of a detailed experimental study performed to examine fluid flow in water-wet fractured sandstone rock. Using high-resolution X-ray micro computed tomography technique, we systematically investigate pore-scale displacement mechanisms and governing interactions between matrix fracture during gas injection. We perform two sets experiments using brine/Soltrol 170 (spreading oil)/nitrogen brine/decalin (nonspreading systems probe possible beneficial role spreading phenomena transferring oil from Gas injection after primary drainage was used generate wide range saturations pore arrangements with both systems. Direct visualization occupancies at different medium reveals significant that layers play maintaining hydraulic conductivity phase fracture. mainly takes place low remaining under condition where layer drainage, presence stable connected layers, is dominant mechanism. In case high saturations, it observed movement primarily governed by piston-like displacements as well ability access elements adjacent Under nonspreading condition, cannot maintain its connectivity due absence leading higher residual lower ultimate recovery.