Abstract 

 Due to the heterogeneity of carbonate rocks, some small pores partially undertaking fows are unresolved in X-ray CT images, therefore have been not appropriately considered in direct fow simulation. By the data fusion of two non-destructive measurements from X-ray CT imaging and nuclear magnetic resonance measurement, this study proposes the construction of ternary-phase domain including resolved apparent-pore, unresolved gray-pore, and resolved solid voxels. Gray-pore voxel containing the unresolved pore is characterized as a microporous structure with equivalent local hydraulic properties according to CT number and pore size distribution. From X-ray CT images of reservoir carbonate rocks from Abu Dhabi, ternary-phase domains are constructed consistently to fgure out local and overall fow behaviors despite the diferent image resolutions. Stokes–Brinkman fow simulation shows that although some apparent-pore volumes are disconnected from each other due to limited resolution, fuid fow can be passed by the gray-pore region. Additionally, a modifed hydraulic tortuosity model is proposed to evaluate the tortuosity of the ternary-phase domain because the conventional hydraulic tortuosity model for the binaryphase domain underestimates the tortuosity of the ternary-phase domain. 

Keywords 

 Unresolved pore · X-ray CT · NMR · Pore size distribution · Direct numerical simulation · Carbonate rock