Schematic of visual real-rock cell (a) different parts of cell, (b) side-view, (c) bottom-view of (a). The parts include (1) stainless steel shield, (2) lower Plexiglass plate, (3) stainless steel lines, (4) opaque silicon rubber O-ring, (5) carbonate rock, (6) transparent PVC sealing rubber, (7) upper Plexiglass plate, (8) stainless steel shield, (9) inlet valve, (10) bolts, (11) outlet valve, (12) nuts. (d) The created fracture inside the rock sample. The fracture aperture is shown with some arrows.